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Measurement, spatial spillover and influencing factors of agricultural carbon emissions efficiency in China
WU Haoyue, HUANG Hanjiao, HE Yu, CHEN Wenkuan
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Effects of tillage and straw returning method on the distribution of carbon and nitrogen in soil aggregates
ZHANG Yuming, HU Chunsheng, CHEN Suying, WANG Yuying, LI Xiaoxin, DONG Wenxu, LIU Xiuping, PEI Lin, ZHANG Hui
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Relationship between policy incentives, ecological cognition, and organic fertilizer application by farmers: Based on a moderated mediation model
SANG Xiance, LUO Xiaofeng, HUANG Yanzhong, TANG Lin
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Spatio-temporal evolution of carbon stocks in the Yellow River Basin based on InVEST and CA-Markov models
YANG Jie, XIE Baopeng, ZHANG Degang
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Effects of straw returning and fertilization on soil bacterial and fungal community structures and diversities in rice-wheat rotation soil
ZHANG Hanlin, BAI Naling, ZHENG Xianqing, LI Shuangxi, ZHANG Juanqin, ZHANG Haiyun, ZHOU Sheng, SUN Huifeng, LYU Weiguang
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2012 Vol. 20, No. 12
Display Method:
2012, 20(12): 1563-1570.
doi: 10.3724/SP.J.1011.2012.01563
Abstract:
This study was a systematic review focusing on vernacular landscapes in different academic realms. It explored ways for effectively building artificial ecosystems with low resources. The research analyzed the development core around two objects of agro-farmland landscapes and rural landscapes. Next, the paper made horizontal comparisons of the differences in aesthetics, sociology, cultural geography, landscape ecology, architecture and landscape architecture disciplines on the object, purpose, method and content of vernacular landscapes. Subsequently, the two major characteristics of previous studies were summarized. The first of these characteristics was that external factors dominated research focused changes of vernacular landscape according to longitudinal observation. The second was that multi-disciplinary interactions played promoting role according to horizontal observation. From the above two characteristics, it was concluded that the man's subjectivity was embodied in the experiences and wisdoms reflected in life. It was also as a result of productions and ecosystems in terms of efficient uses of local resources. There was also the incarnation of the different scales of rural settlement landscapes, farmland landscapes and integral humanism ecosystem. These presented in different material space forms and combinations with typical characteristics and patterns. These experiences and wisdoms deserved serious inheritance and development. Therefore the inherent problem of local landscape research was building efficient artificial ecosystems with low resources. As a result, the concept of vernacular landscape was a rural complex ecosystem fully adapted to specific regional natural and humanistic environments. It reflected the special relationships among humans and lands with long-term effects. At the end, it put forward the outlook of future research as deepened basic theories and nature of problems, which diversified exploration and paradigm convergence of disciplines.
This study was a systematic review focusing on vernacular landscapes in different academic realms. It explored ways for effectively building artificial ecosystems with low resources. The research analyzed the development core around two objects of agro-farmland landscapes and rural landscapes. Next, the paper made horizontal comparisons of the differences in aesthetics, sociology, cultural geography, landscape ecology, architecture and landscape architecture disciplines on the object, purpose, method and content of vernacular landscapes. Subsequently, the two major characteristics of previous studies were summarized. The first of these characteristics was that external factors dominated research focused changes of vernacular landscape according to longitudinal observation. The second was that multi-disciplinary interactions played promoting role according to horizontal observation. From the above two characteristics, it was concluded that the man's subjectivity was embodied in the experiences and wisdoms reflected in life. It was also as a result of productions and ecosystems in terms of efficient uses of local resources. There was also the incarnation of the different scales of rural settlement landscapes, farmland landscapes and integral humanism ecosystem. These presented in different material space forms and combinations with typical characteristics and patterns. These experiences and wisdoms deserved serious inheritance and development. Therefore the inherent problem of local landscape research was building efficient artificial ecosystems with low resources. As a result, the concept of vernacular landscape was a rural complex ecosystem fully adapted to specific regional natural and humanistic environments. It reflected the special relationships among humans and lands with long-term effects. At the end, it put forward the outlook of future research as deepened basic theories and nature of problems, which diversified exploration and paradigm convergence of disciplines.
2012, 20(12): 1571-1578.
doi: 10.3724/SP.J.1011.2012.01571
Abstract:
Due to uneven fertilization, organic matter decomposition and complex community structure, soil nitrogen distribution was highly heterogeneous in intercropped farmlands. Consequently, intercropped crop growth was simultaneously influenced by inter-specific competition and heterogeneous nitrogen. However, there has existed limited knowledge on the relationship between inter-specific competition and heterogeneous nitrogen for crop growth. In the study, the intercropping of maize and potato, an overyielding system in the world, was choose as study objective; the crops were planted in large pots with control-released nitrogen fertilizer, applied either homogeneously or heterogeneously, with or without shoot competition. Plant biomass was measured and then relative interaction index (RII), root foraging precision (RFP) and land equivalent ratio (LER) calculated. The calculations explored the characteristics of the responsiveness of the two crops to heterogeneous nitrogen and shoot competition. The study showed that LER was greater under heterogeneous than under homogeneous nitrogen condition. This was probably due to higher RFP of the two crops under shoot competition. Under shoot competition, however, potato biomass was lower in heterogeneous nitrogen treatment. This was the contrast for maize, whereas without competition, growth of both crops was enhanced by heterogeneous nitrogen treatment. These variations in growth were consistent with those in functional traits including root shoot ratio (RSR), root leaf ratio (RLR), leaf mass fraction (LMF) and root mass fraction (RMF). Consistent with the variations in growth under homogeneous nitrogen treatment, heterogeneous nitrogen treatment increased maize RII and decreased that of potato. Thus while potato had competitive advantage under homogeneous nitrogen treatment, maize had competitive advantage under heterogeneous nitrogen treatment. These results suggested that heterogeneous nitrogen treatment enhanced crop growth and changed relative competitive ability of intercropped crops. Also shoot competition affected characteristics of root foraging of crops. Our study therefore demonstrated that interactions, which affected crop performance, occurred between shoot competition and homogeneous nitrogen treatment. This finding enriched existing knowledge on nitrogen use characteristic which enhanced understanding of complex crop growth performance in intercropped systems.
Due to uneven fertilization, organic matter decomposition and complex community structure, soil nitrogen distribution was highly heterogeneous in intercropped farmlands. Consequently, intercropped crop growth was simultaneously influenced by inter-specific competition and heterogeneous nitrogen. However, there has existed limited knowledge on the relationship between inter-specific competition and heterogeneous nitrogen for crop growth. In the study, the intercropping of maize and potato, an overyielding system in the world, was choose as study objective; the crops were planted in large pots with control-released nitrogen fertilizer, applied either homogeneously or heterogeneously, with or without shoot competition. Plant biomass was measured and then relative interaction index (RII), root foraging precision (RFP) and land equivalent ratio (LER) calculated. The calculations explored the characteristics of the responsiveness of the two crops to heterogeneous nitrogen and shoot competition. The study showed that LER was greater under heterogeneous than under homogeneous nitrogen condition. This was probably due to higher RFP of the two crops under shoot competition. Under shoot competition, however, potato biomass was lower in heterogeneous nitrogen treatment. This was the contrast for maize, whereas without competition, growth of both crops was enhanced by heterogeneous nitrogen treatment. These variations in growth were consistent with those in functional traits including root shoot ratio (RSR), root leaf ratio (RLR), leaf mass fraction (LMF) and root mass fraction (RMF). Consistent with the variations in growth under homogeneous nitrogen treatment, heterogeneous nitrogen treatment increased maize RII and decreased that of potato. Thus while potato had competitive advantage under homogeneous nitrogen treatment, maize had competitive advantage under heterogeneous nitrogen treatment. These results suggested that heterogeneous nitrogen treatment enhanced crop growth and changed relative competitive ability of intercropped crops. Also shoot competition affected characteristics of root foraging of crops. Our study therefore demonstrated that interactions, which affected crop performance, occurred between shoot competition and homogeneous nitrogen treatment. This finding enriched existing knowledge on nitrogen use characteristic which enhanced understanding of complex crop growth performance in intercropped systems.
2012, 20(12): 1579-1585.
doi: 10.3724/SP.J.1011.2012.01579
Abstract:
Soil light fraction is a critical soil quality improvement factor as it regulates soil fertility and minimizes negative environmental impacts. An experiment was established at Southwest University Farm (30°26′N, 106°26′E) in Chongqing. The farm belongs to the Key Field Station for Purple Soil Eco-Environment Monitoring of the Ministry of Agriculture, China. The 0~30 cm soil of the farm under rice/rape rotation system was sampled. The experiment aimed to quantify short-term dynamics of light fraction organic carbon (LFOC) and nitrogen (LFN) during rape growing season. Light fraction was extracted by NaI at a density of 1.8 g·cm-3. The results showed that soil light fraction content in the 0~30 cm soil was 2.95%~5.51% during rape growing season, with an average value of 4.38%. The ranges of LFOC and LFN were 1.44~3.72 g·kg-1 and 0.08~0.17 g·kg-1, with average values of 2.79 g·kg-1 and 0.14 g·kg-1, respectively. Dry weight of LFOC showed distinct seasonal variations, with maxima occurring in mid-growing season, followed by late-growing season. Minimal dry weight of LFOC appeared at the start of the growing season. However, no significant seasonal variations (P > 0.05) were noted in LFN contents in the same period. The observed seasonal variation trend for LFN was similar to that of LFOC. The ratio of LFOC to SOC determined by content (LFOC/SOC) was 9.21%~24.47%, with marked seasonal variations (P< 0.05). This variation trend was similar to that of LFOC. There was no marked seasonal variation in the ratio of LFN to TN (LFN/TN), with a range of 4.55%~12.58% and average of 9.63%. This was higher than those for other areas, suggesting that organic nitrogen in purple paddy soils of Southwest China more easily mineralized with stronger N supply than in other areas. Average C/N ratio of light fraction organic matter was 20.66, with a range of 18.52~25.04. This was higher than that of the total soil (11.66), indicating that bio-availability of light fraction organic matter was higher than soil organic matter. Correlation analysis showed that both LFOC and LFN were positively correlated with root biomass, root carbon and nitrogen (P< 0.01 or P < 0.05). This indicated that root was the main regulator of seasonal dynamics of LFOC and LFN content. Also regression analysis showed that root biomass, root carbon and nitrogen content accounted for 40%~60% of soil LFOC and LFN content. Therefore plant root was concluded to be the key control factor of seasonal variations of LFOC and LFN in the study area.
Soil light fraction is a critical soil quality improvement factor as it regulates soil fertility and minimizes negative environmental impacts. An experiment was established at Southwest University Farm (30°26′N, 106°26′E) in Chongqing. The farm belongs to the Key Field Station for Purple Soil Eco-Environment Monitoring of the Ministry of Agriculture, China. The 0~30 cm soil of the farm under rice/rape rotation system was sampled. The experiment aimed to quantify short-term dynamics of light fraction organic carbon (LFOC) and nitrogen (LFN) during rape growing season. Light fraction was extracted by NaI at a density of 1.8 g·cm-3. The results showed that soil light fraction content in the 0~30 cm soil was 2.95%~5.51% during rape growing season, with an average value of 4.38%. The ranges of LFOC and LFN were 1.44~3.72 g·kg-1 and 0.08~0.17 g·kg-1, with average values of 2.79 g·kg-1 and 0.14 g·kg-1, respectively. Dry weight of LFOC showed distinct seasonal variations, with maxima occurring in mid-growing season, followed by late-growing season. Minimal dry weight of LFOC appeared at the start of the growing season. However, no significant seasonal variations (P > 0.05) were noted in LFN contents in the same period. The observed seasonal variation trend for LFN was similar to that of LFOC. The ratio of LFOC to SOC determined by content (LFOC/SOC) was 9.21%~24.47%, with marked seasonal variations (P< 0.05). This variation trend was similar to that of LFOC. There was no marked seasonal variation in the ratio of LFN to TN (LFN/TN), with a range of 4.55%~12.58% and average of 9.63%. This was higher than those for other areas, suggesting that organic nitrogen in purple paddy soils of Southwest China more easily mineralized with stronger N supply than in other areas. Average C/N ratio of light fraction organic matter was 20.66, with a range of 18.52~25.04. This was higher than that of the total soil (11.66), indicating that bio-availability of light fraction organic matter was higher than soil organic matter. Correlation analysis showed that both LFOC and LFN were positively correlated with root biomass, root carbon and nitrogen (P< 0.01 or P < 0.05). This indicated that root was the main regulator of seasonal dynamics of LFOC and LFN content. Also regression analysis showed that root biomass, root carbon and nitrogen content accounted for 40%~60% of soil LFOC and LFN content. Therefore plant root was concluded to be the key control factor of seasonal variations of LFOC and LFN in the study area.
2012, 20(12): 1586-1593.
doi: 10.3724/SP.J.1011.2012.01586
Abstract:
Plant community structure and composition have been noted to be sensitive to climate change and N deposition in the semiarid grassland of northern China. Despite this fact, little research has been conducted on the response of microbial community in this semi-arid grassland region. The aim of this study was to assess the variations in soil microbial C utilization potential under future scenarios of changes in precipitation and N deposition in the semiarid grassland of northern China. C utilization potential of soil microbial community was determined at community-based physiological profiles in a 3-year field experiment. To simulate changes in precipitation and N deposition in the area under the future scenario, increased precipitation and N treatments were performed in a experiment field in the semiarid grassland at Inner Mongolia. Based on the study, N application and increased precipitation changed the soil environment that in turn significantly influenced soil microbial C utilization. While increased precipitation increased soil moisture and soil organic matter, N application or N application combined with increased precipitation increased soil dissolved inorganic N and decreased soil pH in the semiarid grassland of the study area. Neither sole application of N nor increased precipitation influenced soil microbial C utilization potential. Positive interactions between increased precipitation and N application enhanced microbial C utilization potential, which implied that microbial C utilization potential was somewhat inactive until N and water were available in sufficient amounts. The response of soil microbial community to increased precipitation and N application confirmed the hypothesis that combined increase in precipitation and N application influenced microbial communities in semiarid grasslands. This enhanced microbial C utilization potential with possible acceleration of the C cycle due to future increases in precipitation and N deposition in the semiarid grassland of North China. Correlations between soil microbial C utilization potential and soil/plant factors suggested that soils, microbes and plants reacted with simultaneously increase in precipitation and N application.
Plant community structure and composition have been noted to be sensitive to climate change and N deposition in the semiarid grassland of northern China. Despite this fact, little research has been conducted on the response of microbial community in this semi-arid grassland region. The aim of this study was to assess the variations in soil microbial C utilization potential under future scenarios of changes in precipitation and N deposition in the semiarid grassland of northern China. C utilization potential of soil microbial community was determined at community-based physiological profiles in a 3-year field experiment. To simulate changes in precipitation and N deposition in the area under the future scenario, increased precipitation and N treatments were performed in a experiment field in the semiarid grassland at Inner Mongolia. Based on the study, N application and increased precipitation changed the soil environment that in turn significantly influenced soil microbial C utilization. While increased precipitation increased soil moisture and soil organic matter, N application or N application combined with increased precipitation increased soil dissolved inorganic N and decreased soil pH in the semiarid grassland of the study area. Neither sole application of N nor increased precipitation influenced soil microbial C utilization potential. Positive interactions between increased precipitation and N application enhanced microbial C utilization potential, which implied that microbial C utilization potential was somewhat inactive until N and water were available in sufficient amounts. The response of soil microbial community to increased precipitation and N application confirmed the hypothesis that combined increase in precipitation and N application influenced microbial communities in semiarid grasslands. This enhanced microbial C utilization potential with possible acceleration of the C cycle due to future increases in precipitation and N deposition in the semiarid grassland of North China. Correlations between soil microbial C utilization potential and soil/plant factors suggested that soils, microbes and plants reacted with simultaneously increase in precipitation and N application.
2012, 20(12): 1594-1598.
doi: 10.3724/SP.J.1011.2012.01594
Abstract:
A field experiment was conducted in Wuqiao Experimental Station of China Agricultural University in 2011. Four nitrogen (N) application patterns were compared: N application rate of 90 kg·hm-2 before sowing (NAT I); N application rate of 190 kg·hm-2 with 150 kg·hm-2 before sowing and 40 kg·hm-2 at jointing (NAT II); N application rate of 250 kg·hm-2 with 90 kg·hm-2 before sowing and 160 kg·hm-2 at jointing (NAT III); and N application rate of 300 kg·hm-2 with 50 kg·hm-2 before sowing, 150 kg·hm-2 at jointing and 100 kg·hm-2 at silking (NAT IV). The objective of the study was to throw in-depth light on how the mechanisms of N application at silking stage in addition to basal and jointing N fertilization increase summer maize yield. Yield and grain-filling rates of summer maize were also analyzed. The results showed that N application at silking stage in addition to basal and jointing N fertilization (NAT IV) reduced the number of dead leaves. Leaf senesces rates were 0.01~0.02 leaf·d-1, 0.01~0.05 leaf·d-1, 0.02~0.04 leaf·d-1, respectively, less than those of N treatments without silking N fertilization at 11~20 d, 21~30 d, 31~40 d after silking. Ear leaf SPAD peak value was somewhat higher in NAT IV than that of other treatments, and the reduction of SPAD at middle and later filling stage was delayed. Furthermore, peak of NAT IV filling rate improved by 8.5% over that of NAT Ⅲ and with simultaneous increase in grain volume. Maize grain N uptake after silking significantly improved in NAT IV (grain nitrogen absorption peak in NAT IV was 1.65, 1.45 and 1.31 times than those of NAT Ⅰ, NATⅡ and NAT Ⅲ, respectively). N harvest index was 2.5%~13.3% greater in NAT IV than in the other treatments. Compared to kernel per ear, grain weight was more affected by N application at silking stage. Both ear traits and yield formation were improved under NAT IV, and yield increased by 200 kg·hm-2, 300 kg·hm-2 and 400 kg·hm-2, respectively compared with NAT I, II, III. It was concluded that silking fertilization in summer maize delayed decreasing of photosynthetic area after silking. This provided more grain filling source that in turn improved grain weight and yield.
A field experiment was conducted in Wuqiao Experimental Station of China Agricultural University in 2011. Four nitrogen (N) application patterns were compared: N application rate of 90 kg·hm-2 before sowing (NAT I); N application rate of 190 kg·hm-2 with 150 kg·hm-2 before sowing and 40 kg·hm-2 at jointing (NAT II); N application rate of 250 kg·hm-2 with 90 kg·hm-2 before sowing and 160 kg·hm-2 at jointing (NAT III); and N application rate of 300 kg·hm-2 with 50 kg·hm-2 before sowing, 150 kg·hm-2 at jointing and 100 kg·hm-2 at silking (NAT IV). The objective of the study was to throw in-depth light on how the mechanisms of N application at silking stage in addition to basal and jointing N fertilization increase summer maize yield. Yield and grain-filling rates of summer maize were also analyzed. The results showed that N application at silking stage in addition to basal and jointing N fertilization (NAT IV) reduced the number of dead leaves. Leaf senesces rates were 0.01~0.02 leaf·d-1, 0.01~0.05 leaf·d-1, 0.02~0.04 leaf·d-1, respectively, less than those of N treatments without silking N fertilization at 11~20 d, 21~30 d, 31~40 d after silking. Ear leaf SPAD peak value was somewhat higher in NAT IV than that of other treatments, and the reduction of SPAD at middle and later filling stage was delayed. Furthermore, peak of NAT IV filling rate improved by 8.5% over that of NAT Ⅲ and with simultaneous increase in grain volume. Maize grain N uptake after silking significantly improved in NAT IV (grain nitrogen absorption peak in NAT IV was 1.65, 1.45 and 1.31 times than those of NAT Ⅰ, NATⅡ and NAT Ⅲ, respectively). N harvest index was 2.5%~13.3% greater in NAT IV than in the other treatments. Compared to kernel per ear, grain weight was more affected by N application at silking stage. Both ear traits and yield formation were improved under NAT IV, and yield increased by 200 kg·hm-2, 300 kg·hm-2 and 400 kg·hm-2, respectively compared with NAT I, II, III. It was concluded that silking fertilization in summer maize delayed decreasing of photosynthetic area after silking. This provided more grain filling source that in turn improved grain weight and yield.
Soil respiration and its influencing factors in rice-rape rotation fields during rape growing season
2012, 20(12): 1599-1605.
doi: 10.3724/SP.J.1011.2012.01599
Abstract:
Soil is a major biosphere for carbon (C) reserve, containing globally twice C as much as the atmosphere and three times as much as vegetation. After photosynthesis, soil respiration remains the second largest carbon flux in the ecosystem, accounting for 60%~90% of total ecosystem respiration. Small changes in soil respiration across large areas have been reported to produce significant effects on CO2 atmospheric concentrations. This has led to potential positive feedbacks between increasing temperature and enhanced soil respiration that in turn accelerate global warming. Therefore, soil respiration has become a critical research field in global carbon cycle. Soil respiration in specific ecosystems has been characterized in terms of magnitude, and temporal and spatial variability. Detail on soil respiration and the controlling factors have been critical for constraining ecosystem C budget and understanding soil response to global climate change. In this paper a rice-rape rotation field in Southwest China was used to study the spatial and temporal variations in soil respiration during rape growth season in November 2009 through April 2010. Soil respiration rates were measured on monthly basis using the closed chamber technique and three measurement positions (on-plant, inter-plants and inter-rows) selected. The results showed that diurnal patterns of soil respiration followed uni-humped curves. Maximum soil respiration rates appeared at 15:00 and minimum at 7:00. Soil respiration rates showed significant seasonal changes: initially declined and then increased during the experimental period. The order of daily average soil respiration rates was March 27, 2010 (293.25 mg·m-2·h-1) > April 17, 2010 (275.22 mg·m-2·h-1) > February 28, 2010 (186.25 mg·m-2·h-1) > January 28, 2010 (164.44 mg·m-2·h-1) > November 22, 2009 (140.25 mg·m-2·h-1) > December 20, 2009 (102.07 mg·m-2·h-1). There were significant spatial variations in soil respiration patterns at the plant scale. Higher soil respiration rates tended to occur near rape plants during growth season. On-plant soil respiration rates were highest (336.71 mg·m-2·h-1), followed by inter-plant (248.48 mg·m-2·h-1) and then inter-row (141.77 mg·m-2·h-1). Soil respiration was calculated as the sum of root and microbial respiration. The contribution of each group required thorough understanding in order to evaluate the implications of environmental changes for soil carbon cycling and sequestration. In this study, direct microbial respiration rates were observed in inter-row plots without roots. Therefore root respiration was the difference between soil respiration rates of planted and unplanted soils. Average contribution of root respiration to soil respiration was 51.03%, with a range of 25.78%~72.61%. Soil respiration rate was affected by several environmental factors. It was exponentially correlated with soil temperature, linearly correlated with root biomass, and positively correlated with soil microbial biomass carbon. Soil respiration was also readily affected by oxidized carbon and particulate organic carbon.
Soil is a major biosphere for carbon (C) reserve, containing globally twice C as much as the atmosphere and three times as much as vegetation. After photosynthesis, soil respiration remains the second largest carbon flux in the ecosystem, accounting for 60%~90% of total ecosystem respiration. Small changes in soil respiration across large areas have been reported to produce significant effects on CO2 atmospheric concentrations. This has led to potential positive feedbacks between increasing temperature and enhanced soil respiration that in turn accelerate global warming. Therefore, soil respiration has become a critical research field in global carbon cycle. Soil respiration in specific ecosystems has been characterized in terms of magnitude, and temporal and spatial variability. Detail on soil respiration and the controlling factors have been critical for constraining ecosystem C budget and understanding soil response to global climate change. In this paper a rice-rape rotation field in Southwest China was used to study the spatial and temporal variations in soil respiration during rape growth season in November 2009 through April 2010. Soil respiration rates were measured on monthly basis using the closed chamber technique and three measurement positions (on-plant, inter-plants and inter-rows) selected. The results showed that diurnal patterns of soil respiration followed uni-humped curves. Maximum soil respiration rates appeared at 15:00 and minimum at 7:00. Soil respiration rates showed significant seasonal changes: initially declined and then increased during the experimental period. The order of daily average soil respiration rates was March 27, 2010 (293.25 mg·m-2·h-1) > April 17, 2010 (275.22 mg·m-2·h-1) > February 28, 2010 (186.25 mg·m-2·h-1) > January 28, 2010 (164.44 mg·m-2·h-1) > November 22, 2009 (140.25 mg·m-2·h-1) > December 20, 2009 (102.07 mg·m-2·h-1). There were significant spatial variations in soil respiration patterns at the plant scale. Higher soil respiration rates tended to occur near rape plants during growth season. On-plant soil respiration rates were highest (336.71 mg·m-2·h-1), followed by inter-plant (248.48 mg·m-2·h-1) and then inter-row (141.77 mg·m-2·h-1). Soil respiration was calculated as the sum of root and microbial respiration. The contribution of each group required thorough understanding in order to evaluate the implications of environmental changes for soil carbon cycling and sequestration. In this study, direct microbial respiration rates were observed in inter-row plots without roots. Therefore root respiration was the difference between soil respiration rates of planted and unplanted soils. Average contribution of root respiration to soil respiration was 51.03%, with a range of 25.78%~72.61%. Soil respiration rate was affected by several environmental factors. It was exponentially correlated with soil temperature, linearly correlated with root biomass, and positively correlated with soil microbial biomass carbon. Soil respiration was also readily affected by oxidized carbon and particulate organic carbon.
2012, 20(12): 1606-1613.
doi: 10.3724/SP.J.1011.2012.01606
Abstract:
The super hybrid rice “Liangyoupeijiu” was used as the test material in comparison with “Shanyou 63” and “9311”. The comparison studied the changes in the activities of key enzymes involved in nitrogen metabolism, included NR (nitrate reductase), GS (glutamine synthetase), GPT (glutamic-pyruvie transaminase), GOT (glutamic-oxalacetic transaminase), GDH (glutamate dehydrogenase) and protease, in rice flag-leaves at the late developmental stage. The kinetics of NR, GS and GPT, contents of soluble proteins and free amino acids, and panicle traits were also investigated at the same time. The study was to build better understanding into the changes in the activities and dynamics of enzymes related with nitrogen metabolism in super hybrid rice, its parents and control variety at the late developmental stage. The study further explored the inherent mechanisms of these changes and provided scientific basis for regulating nitrogen metabolism in hybrid rice at the late developmental stage. The results showed that one week after blooming was the high-value duration of the activities of enzymes related with nitrogen metabolism in flag-leaves of the three rice varieties. After one week, the enzymes activities entered into the sharp-fall phase. The NR, GS, GPT and GDH activities and speaks activities among the varieties were significantly different. One week after blooming, higher activities of GS and GDH in “Liangyoupeijiu” rice variety were noted. Then 7~14 days after blooming, NR and GS activities in “Shanyou 63” rice were significantly higher than those of “9311” and “Liangyoupeijiu”. Also GS and GDH activities and peak activities in “Shanyou 63” were higher and occurred at much later dates than those in the other two varieties at late grain-filling stage. At flowering and initial grain-filling stages, “9311” had higher trans-aminase and catalytic activities with nitrogen metabolism starting earlier than in the other varieties. The changes in GDH and GOT activities at late developmental stage suggested that oxidative deamination was the main vivo process. The relation between activities and catalytic activity of NR and GS were nonlinear at late developmental stage. Catalytic activity of GPT was lowest at 14 days after anthesis. As three kinds of enzymes at the late grain-filling stage still had higher catalytic activity combined with changes in soluble proteins and ATPase activity in flag-leaves, it was proposed that the contents of protein enzymes were the main factors affecting enzyme activity and nitrogen metabolism at the late developmental stage. The energy state of flag-leaves was an important limiting factor to the availability of physiological activity. The inter-specific hybrid rice (“Shanyou 63”) had the advantage of high physiological activity in the leaf and grain-filling stages than the sub-specific hybrid rice (“Liangyoupeijiu”). This was the main sources of changes in key enzyme activities, grain-filling rates and panicle traits.
The super hybrid rice “Liangyoupeijiu” was used as the test material in comparison with “Shanyou 63” and “9311”. The comparison studied the changes in the activities of key enzymes involved in nitrogen metabolism, included NR (nitrate reductase), GS (glutamine synthetase), GPT (glutamic-pyruvie transaminase), GOT (glutamic-oxalacetic transaminase), GDH (glutamate dehydrogenase) and protease, in rice flag-leaves at the late developmental stage. The kinetics of NR, GS and GPT, contents of soluble proteins and free amino acids, and panicle traits were also investigated at the same time. The study was to build better understanding into the changes in the activities and dynamics of enzymes related with nitrogen metabolism in super hybrid rice, its parents and control variety at the late developmental stage. The study further explored the inherent mechanisms of these changes and provided scientific basis for regulating nitrogen metabolism in hybrid rice at the late developmental stage. The results showed that one week after blooming was the high-value duration of the activities of enzymes related with nitrogen metabolism in flag-leaves of the three rice varieties. After one week, the enzymes activities entered into the sharp-fall phase. The NR, GS, GPT and GDH activities and speaks activities among the varieties were significantly different. One week after blooming, higher activities of GS and GDH in “Liangyoupeijiu” rice variety were noted. Then 7~14 days after blooming, NR and GS activities in “Shanyou 63” rice were significantly higher than those of “9311” and “Liangyoupeijiu”. Also GS and GDH activities and peak activities in “Shanyou 63” were higher and occurred at much later dates than those in the other two varieties at late grain-filling stage. At flowering and initial grain-filling stages, “9311” had higher trans-aminase and catalytic activities with nitrogen metabolism starting earlier than in the other varieties. The changes in GDH and GOT activities at late developmental stage suggested that oxidative deamination was the main vivo process. The relation between activities and catalytic activity of NR and GS were nonlinear at late developmental stage. Catalytic activity of GPT was lowest at 14 days after anthesis. As three kinds of enzymes at the late grain-filling stage still had higher catalytic activity combined with changes in soluble proteins and ATPase activity in flag-leaves, it was proposed that the contents of protein enzymes were the main factors affecting enzyme activity and nitrogen metabolism at the late developmental stage. The energy state of flag-leaves was an important limiting factor to the availability of physiological activity. The inter-specific hybrid rice (“Shanyou 63”) had the advantage of high physiological activity in the leaf and grain-filling stages than the sub-specific hybrid rice (“Liangyoupeijiu”). This was the main sources of changes in key enzyme activities, grain-filling rates and panicle traits.
CHEN Dong-Mei,
WU Wen-Xiang,
WANG Hai-Bin,
HUANG Jin-Wen,
CHEN Lan-Lan,
YOU Chui-Huai,
WU Lin-Kun,
ZHANG Zhong-Yi,
LIN Wen-Xiong
2012, 20(12): 1614-1620.
doi: 10.3724/SP.J.1011.2012.01614
Abstract:
Different concentrations (T1: 40 μg·mL-1; T2: 120 μg·mL-1; CK: 0 μg·mL-1) of tobacco-cultivated soil extracts were used to pot-soils to determine the effects of continuous tobacco cropping on tobacco growth and bacterial community diversity in rhizosphere soils. The results indicated that soil extracts significantly inhibited tobacco growth, dwarfed tobacco plant, reduced tobacco leaf area and photosynthesis, and destroyed protective enzymes in tobacco plants. MDA enhancement in tobacco plants was noted. Tobacco MDA in T2 was 2.44 times higher than that in CK. Tobacco growth inhibition was significantly enhanced with increasing concentration of soil extracts. Analysis of T-RFs suggested that 17 plylums and 24 classes rhizospheric bacteria existed in CK soils, 14 plylums and 21 classes in T1 soils and 10 plylums and 17 classes in T2 soils. A similar trend was also noted for Margalef index. The results suggested that bacterial community diversity dropped significantly with increasing concentration of soil extracts. Microbial/plant-growth analysis showed that a large proportion of T-RFs derived from soils treated with soil extracts had negative correlations with tobacco growth, and with most T-RFs identified as pathogens. However, a large proportion of T-RFs derived from CK showed positive correlation with tobacco growth, and with several corresponding T-RFs bacteria were involved in soil nutrient recycling. In conclusion thus, tobacco-cultivated soil extracts inhibited tobacco growth, destroyed soil micro-system balance, and reduced bacterial community diversity. The results suggested that soil autotoxic allelochemical accumulation was a major limiting factor in continuous tobacco cropping.
Different concentrations (T1: 40 μg·mL-1; T2: 120 μg·mL-1; CK: 0 μg·mL-1) of tobacco-cultivated soil extracts were used to pot-soils to determine the effects of continuous tobacco cropping on tobacco growth and bacterial community diversity in rhizosphere soils. The results indicated that soil extracts significantly inhibited tobacco growth, dwarfed tobacco plant, reduced tobacco leaf area and photosynthesis, and destroyed protective enzymes in tobacco plants. MDA enhancement in tobacco plants was noted. Tobacco MDA in T2 was 2.44 times higher than that in CK. Tobacco growth inhibition was significantly enhanced with increasing concentration of soil extracts. Analysis of T-RFs suggested that 17 plylums and 24 classes rhizospheric bacteria existed in CK soils, 14 plylums and 21 classes in T1 soils and 10 plylums and 17 classes in T2 soils. A similar trend was also noted for Margalef index. The results suggested that bacterial community diversity dropped significantly with increasing concentration of soil extracts. Microbial/plant-growth analysis showed that a large proportion of T-RFs derived from soils treated with soil extracts had negative correlations with tobacco growth, and with most T-RFs identified as pathogens. However, a large proportion of T-RFs derived from CK showed positive correlation with tobacco growth, and with several corresponding T-RFs bacteria were involved in soil nutrient recycling. In conclusion thus, tobacco-cultivated soil extracts inhibited tobacco growth, destroyed soil micro-system balance, and reduced bacterial community diversity. The results suggested that soil autotoxic allelochemical accumulation was a major limiting factor in continuous tobacco cropping.
2012, 20(12): 1621-1625.
doi: 10.3724/SP.J.1011.2012.01621
Abstract:
Plutella xylostella is one of the main pests that affect vegetable commodity output. Current treatment by chemical pesticide spray has been considered the effective control of P. xylostella. This treatment has also developed the insecticide resistance, increased pesticide residue risks and threatened pollution-free vegetable production. In the present study, the effects of abio-chemical conditions such as temperature, soil moisture, water-logging and soil cover on P. xylostella pupae eclosion were investigated. The study aimed to elucidate agro-measure control effects, especially those of paddy/dryland rotation and soil plowing, on P. xylostella. The results showed that the rate of pupa emergence exceeded 73% at 26~30 ℃, which declined to 46.67% at 34 ℃. When treated at 4 ℃ and then grown at room temperature, the rate of pupae emergence dropped significantly. The longer the 4 ℃ pretreatment, the lower was the rate of pupae emergence. However, the emergency rate recovered to normal levels after long time of growth at room temperature. When soil moisture was 10% and 20%，the emergence rate was respectively 12.5% and 6.2% of that under normal moisture condition. No pupa emergence was observed within 6 d at soil moisture of 30%. When treated with water-logging for 12 h and 24 h and then returned to surface soil, the rate of emergence of P. xylostella pupae dropped respectively by 25.0% and 50.0% and emergency was delayed too. No pupa emergence was observed under extended treatment time of 36 h. Soil covering also had noticeable effects on P. xylostella pupa emergence. The emergence of pupae was delayed by 2 d when covered at 1 cm depth soil. Pupa did not successfully emerge when soil cover was 1.5 cm deep. The above results suggested that timely irrigation, paddy/dryland rotation and soil plowing were critical control factors of P. xylostella pupae in vegetable fields.
Plutella xylostella is one of the main pests that affect vegetable commodity output. Current treatment by chemical pesticide spray has been considered the effective control of P. xylostella. This treatment has also developed the insecticide resistance, increased pesticide residue risks and threatened pollution-free vegetable production. In the present study, the effects of abio-chemical conditions such as temperature, soil moisture, water-logging and soil cover on P. xylostella pupae eclosion were investigated. The study aimed to elucidate agro-measure control effects, especially those of paddy/dryland rotation and soil plowing, on P. xylostella. The results showed that the rate of pupa emergence exceeded 73% at 26~30 ℃, which declined to 46.67% at 34 ℃. When treated at 4 ℃ and then grown at room temperature, the rate of pupae emergence dropped significantly. The longer the 4 ℃ pretreatment, the lower was the rate of pupae emergence. However, the emergency rate recovered to normal levels after long time of growth at room temperature. When soil moisture was 10% and 20%，the emergence rate was respectively 12.5% and 6.2% of that under normal moisture condition. No pupa emergence was observed within 6 d at soil moisture of 30%. When treated with water-logging for 12 h and 24 h and then returned to surface soil, the rate of emergence of P. xylostella pupae dropped respectively by 25.0% and 50.0% and emergency was delayed too. No pupa emergence was observed under extended treatment time of 36 h. Soil covering also had noticeable effects on P. xylostella pupa emergence. The emergence of pupae was delayed by 2 d when covered at 1 cm depth soil. Pupa did not successfully emerge when soil cover was 1.5 cm deep. The above results suggested that timely irrigation, paddy/dryland rotation and soil plowing were critical control factors of P. xylostella pupae in vegetable fields.
2012, 20(12): 1626-1630.
doi: 10.3724/SP.J.1011.2012.01626
Abstract:
To clarify the effects of UV-B radiation on the biological characteristics of different color morphs of pea aphid [Acyrthosiphon pisum (Harris)], new-born nymphs of two colors (red and green) pea aphid morph were irradiated with 40 W UV-B lamp for 30 min per day for 5 days. The morphs were bred in an artificial bioclimatic chamber under strict temperature conditions of 16 ℃, 20 ℃ and 24 ℃, and in two alfalfa (“Gannong 3” and “Gannong 5”) cultivars. Development duration, mass difference and mean relative growth rate per day (MRGR) of the different color pea aphids were measured. The results suggested that UV-radiation less affected growth duration, mass difference and MRGR of red and green color pea aphid morphs in “Gannong 3” (P > 0.05) at 16 ℃. At 20 ℃, development duration of red color morphs in “Gannong 3” delayed and MRGR dropped (P < 0.05), but mass difference of red color morphs in “Gannong 3” was insignificant (P > 0.05) under UV-B radiation. At 24 ℃, development duration of green color morphs in “Gannong 3” delayed, and mass difference and MRGR of green color morphs in “Gannong 3” dropped (P < 0.05) under UV-B radiation. While at 16 ℃, UV-B radiation delayed development duration and reduced mass difference and MRGR of red color morphs in “Gannong 5” (P < 0.05), it delayed development duration and reduced mass difference and MRGR of green color morphs in “Gannong 5” (P < 0.05) at 20 ℃ and 24 ℃. The findings suggested that red and green color pea aphid morphs responded differently to UV-B radiation, which responses were relative to temperature and alfalfa variety.
To clarify the effects of UV-B radiation on the biological characteristics of different color morphs of pea aphid [Acyrthosiphon pisum (Harris)], new-born nymphs of two colors (red and green) pea aphid morph were irradiated with 40 W UV-B lamp for 30 min per day for 5 days. The morphs were bred in an artificial bioclimatic chamber under strict temperature conditions of 16 ℃, 20 ℃ and 24 ℃, and in two alfalfa (“Gannong 3” and “Gannong 5”) cultivars. Development duration, mass difference and mean relative growth rate per day (MRGR) of the different color pea aphids were measured. The results suggested that UV-radiation less affected growth duration, mass difference and MRGR of red and green color pea aphid morphs in “Gannong 3” (P > 0.05) at 16 ℃. At 20 ℃, development duration of red color morphs in “Gannong 3” delayed and MRGR dropped (P < 0.05), but mass difference of red color morphs in “Gannong 3” was insignificant (P > 0.05) under UV-B radiation. At 24 ℃, development duration of green color morphs in “Gannong 3” delayed, and mass difference and MRGR of green color morphs in “Gannong 3” dropped (P < 0.05) under UV-B radiation. While at 16 ℃, UV-B radiation delayed development duration and reduced mass difference and MRGR of red color morphs in “Gannong 5” (P < 0.05), it delayed development duration and reduced mass difference and MRGR of green color morphs in “Gannong 5” (P < 0.05) at 20 ℃ and 24 ℃. The findings suggested that red and green color pea aphid morphs responded differently to UV-B radiation, which responses were relative to temperature and alfalfa variety.
2012, 20(12): 1631-1635.
doi: 10.3724/SP.J.1011.2012.01631
Abstract:
The effects of temperature, host vegetables and initial inoculation density of root-knot nematode (Meloidogyne incognita) on root-knot nematode driven vegetable symptoms were investigated under greenhouse conditions. The results showed that the optimum temperature for root-knot nematode incidence from May to September was 22.17~27.61 ℃, with obvious symptom detection in cucumber plants after three days. When temperature was 15.38~18.67 ℃ during January to April and October to December, obvious symptom detection in cucumber plants was after 15 days. Symptom appearance time was delayed and disease incidence inhibited. 15 different host plants were infected by the second-stage juveniles of M. incognita. Symptoms appeared in 10 days for watermelon, melon, bitter-gourd, cucumber, pumpkin, squash and green grocery. There were 5 days later for tomato, cowpea, eggplant cabbage and celery. Symptom appearance time in leek and welsh onion was the longest, without becoming obvious after 30 days. The infection ability of M. incognita varied significantly among the six vegetables (cucumber, tomato, eggplant, green grocery, leek and pepper). The numbers of second-stage M. incognita juveniles in rhizosphere soil and adult females and egg-masses in cucumber and tomato roots were more than those in eggplant, green grocery, leek and pepper. With initial inoculation density enhancement of second-stage juveniles, obvious symptoms appeared earlier in tomatoes with a more severe disease index. When inoculation density of second-stage M. incognita juveniles was 80·100 g-1(soil), obvious symptoms appeared in tomatoes after four days. At second-stage M. incognita juvenile inoculation rate of 160·100 g-1(soil), it exceed saturation density thereby suppressing disease rate and index.
The effects of temperature, host vegetables and initial inoculation density of root-knot nematode (Meloidogyne incognita) on root-knot nematode driven vegetable symptoms were investigated under greenhouse conditions. The results showed that the optimum temperature for root-knot nematode incidence from May to September was 22.17~27.61 ℃, with obvious symptom detection in cucumber plants after three days. When temperature was 15.38~18.67 ℃ during January to April and October to December, obvious symptom detection in cucumber plants was after 15 days. Symptom appearance time was delayed and disease incidence inhibited. 15 different host plants were infected by the second-stage juveniles of M. incognita. Symptoms appeared in 10 days for watermelon, melon, bitter-gourd, cucumber, pumpkin, squash and green grocery. There were 5 days later for tomato, cowpea, eggplant cabbage and celery. Symptom appearance time in leek and welsh onion was the longest, without becoming obvious after 30 days. The infection ability of M. incognita varied significantly among the six vegetables (cucumber, tomato, eggplant, green grocery, leek and pepper). The numbers of second-stage M. incognita juveniles in rhizosphere soil and adult females and egg-masses in cucumber and tomato roots were more than those in eggplant, green grocery, leek and pepper. With initial inoculation density enhancement of second-stage juveniles, obvious symptoms appeared earlier in tomatoes with a more severe disease index. When inoculation density of second-stage M. incognita juveniles was 80·100 g-1(soil), obvious symptoms appeared in tomatoes after four days. At second-stage M. incognita juvenile inoculation rate of 160·100 g-1(soil), it exceed saturation density thereby suppressing disease rate and index.
2012, 20(12): 1636-1642.
doi: 10.3724/SP.J.1011.2012.01636
Abstract:
Chlorpyrifos [(O,O-diethyl-O-3,5,6-trichloro-2-pyridinyl) phosphorothioate] is a broad spectrum of moderately toxic organophosphorus pesticide used as insecticide on a large variety of crops including fruits, vegetables, cotton, corn and wheat. With especially the recent elimination of five highly toxic organophosphorus pesticides, chlorpyrifos has been widely used in China. Consequently, large quantities of wastewater containing chlorpyrifos have been generated from pesticide industry and lot more chlorpyrifos scattered in the depths of soils and waters in the fields. Moreover, various reports have noted that chlorpyrifos have had visible toxicity in mammalians. Therefore the high degree of persistence of chlorpyrifos in the environment and the toxic effects on humans had necessitated removal. Biodegradation has received increasing attention as an efficient and cheap biotechnological approach to cleaning up polluted environments. Several chemicals have been successfully removed from soil and aquatic environments using degrading microbes. Similarly, biodegradation has been the major mechanism for removing chlorpyrifos residues, especially for treatments of discharged wastewater from the processes of chlorpyrifos production. Previous successes in isolating Bacillus cereus strain from chlorpyrifos degradation have augmented scarce literatures on this strain of chlorpyrifos biodegradation. In order to enhance degradation efficiency, B. cereus HY-1 strain was immobilized with sodium alginate using the syringe titration method. Also biodegradation characteristics of chlorpyrifos by immobilized B. cereus strain were further investigated. While the optimal reaction time was obtained, the effects of the various parameters (e.g., amounts of immobilized biomass, pH and chlorpyrifos initial concentration) of biodegradation were studied. The results showed that chlorpyrifos were readily degraded by sodium alginate immobilized B.cereus. The appropriate concentration of sodium alginate was 2.5% (w/v), with an average particle diameter of 3 mm. The appropriate incubation time was 60 h, with maximum degradation rate of 100 mg·L-1 chlorpyrifos. No significant increase was noted in chlorpyrifos degradation rate with increasing reaction time. Chlorpyrifos degradation efficiency was highest when immobilized biomass was 160 g·L-1. Under ensured degradation efficiency condition, immobilized bacteria amount dropped, which also reduced production costs. Immobilized strains were broadly adaptable to a wide range of pH, with more conducive alkaline conditions for chlorpyrifos degradation. Compared with high initial chlorpyrifos concentrations, degradation rates at low initial chlorpyrifos concentrations (80 mg·L-1 and 100 mg·L-1) were higher. Chlorpyrifos degradation rate reached 90% at 100 mg·L-1. But with increasing concentration, chlorpyrifos degradation rate declined. This showed that immobilized bacteria tolerance to chlorpyrifos concentration was within a certain limit. Immobilized bacteria were reusable in chlorpyrifos degradation processes. With repeated use (4 times) of immobilized bacteria, though immobilized bacteria disintegrated, the degradation rate at 100 mg·L-1 of chlorpyrifos was up to 47%. Therefore immobilized strains showed high application values in removing chlorpyrifos residue with wide environmental adaptability ranges.
Chlorpyrifos [(O,O-diethyl-O-3,5,6-trichloro-2-pyridinyl) phosphorothioate] is a broad spectrum of moderately toxic organophosphorus pesticide used as insecticide on a large variety of crops including fruits, vegetables, cotton, corn and wheat. With especially the recent elimination of five highly toxic organophosphorus pesticides, chlorpyrifos has been widely used in China. Consequently, large quantities of wastewater containing chlorpyrifos have been generated from pesticide industry and lot more chlorpyrifos scattered in the depths of soils and waters in the fields. Moreover, various reports have noted that chlorpyrifos have had visible toxicity in mammalians. Therefore the high degree of persistence of chlorpyrifos in the environment and the toxic effects on humans had necessitated removal. Biodegradation has received increasing attention as an efficient and cheap biotechnological approach to cleaning up polluted environments. Several chemicals have been successfully removed from soil and aquatic environments using degrading microbes. Similarly, biodegradation has been the major mechanism for removing chlorpyrifos residues, especially for treatments of discharged wastewater from the processes of chlorpyrifos production. Previous successes in isolating Bacillus cereus strain from chlorpyrifos degradation have augmented scarce literatures on this strain of chlorpyrifos biodegradation. In order to enhance degradation efficiency, B. cereus HY-1 strain was immobilized with sodium alginate using the syringe titration method. Also biodegradation characteristics of chlorpyrifos by immobilized B. cereus strain were further investigated. While the optimal reaction time was obtained, the effects of the various parameters (e.g., amounts of immobilized biomass, pH and chlorpyrifos initial concentration) of biodegradation were studied. The results showed that chlorpyrifos were readily degraded by sodium alginate immobilized B.cereus. The appropriate concentration of sodium alginate was 2.5% (w/v), with an average particle diameter of 3 mm. The appropriate incubation time was 60 h, with maximum degradation rate of 100 mg·L-1 chlorpyrifos. No significant increase was noted in chlorpyrifos degradation rate with increasing reaction time. Chlorpyrifos degradation efficiency was highest when immobilized biomass was 160 g·L-1. Under ensured degradation efficiency condition, immobilized bacteria amount dropped, which also reduced production costs. Immobilized strains were broadly adaptable to a wide range of pH, with more conducive alkaline conditions for chlorpyrifos degradation. Compared with high initial chlorpyrifos concentrations, degradation rates at low initial chlorpyrifos concentrations (80 mg·L-1 and 100 mg·L-1) were higher. Chlorpyrifos degradation rate reached 90% at 100 mg·L-1. But with increasing concentration, chlorpyrifos degradation rate declined. This showed that immobilized bacteria tolerance to chlorpyrifos concentration was within a certain limit. Immobilized bacteria were reusable in chlorpyrifos degradation processes. With repeated use (4 times) of immobilized bacteria, though immobilized bacteria disintegrated, the degradation rate at 100 mg·L-1 of chlorpyrifos was up to 47%. Therefore immobilized strains showed high application values in removing chlorpyrifos residue with wide environmental adaptability ranges.
2012, 20(12): 1643-1649.
doi: 10.3724/SP.J.1011.2012.01643
Abstract:
As an innovative farming system, integrated “plant-fish” farming has since 2010 developed rapidly in the lowland areas of North Zhejiang Province. This region generally lies in very low altitudes. To optimize integrated aquatic vegetable cultivation in “plant-fish” farming systems, a comparative experiment was carried out in two farms. The growth, quality and food security of Nelumbo nucifera and Trapa acornis in different integrated aquaculture farming systems were analyzed. The results showed that the growth and development, commodity feature and quality of N. nucifera improved in integrated “plant-fish” farming systems. Compared with monocropping system of N. nucifera (control), “plant-fish” integrated farming systems increased N. nucifera leaf length, leaf width and petiole length by 1.2%~38.2%, 8.6%~30.9% and 10.1%~33.2%, respectively. Similarly, N. nucifera commodity features improved under integrated “plant-fish” farming systems. Total tuber weight and maximum tuber node weight of N. nucifera in “plant-fish” integrated farming systems increased by 19.0%~77.8% and 22.0%~77.5%, respectively, compared with the control. N. nucifera nutritional quality also improved. N. nucifera contents of starch, protein and total amino acids in “N. nucifera-Pelteobagrus fulvidraco and Misgurnus anguillicaudatus” farming system increased by 34.0%, 47.3% and 48.7%, respectively, compared with the control. Also those in “N. nucifera-Carassius auratus and P. fulvidraco” system were respectively 23.3%, 5.4% and 11.3% higher than those in the control. In “N. nucifera-Ophicephalus argus” system, N. nucifera starch content was 31.1% higher than that in the control. However, the contents of protein and total amino acids decreased respectively by 20.4% and 5.3% over the control. The results also showed that in “T. acornis-Trionyx sinensis” system, growth, development and commodity features of T. acornis increased significantly. T. acornis leaf and phyllome size was larger than that of the control (monocropped T. acornis in fishpond). Also T. acornis fruit fresh weight was 6.2% higher than the control, but contents of rough protein and total amino acids were 16.0% and 17.0% lower than the control. Under “T. acornis-O. argus” farming system, T. acornis growth and development were lower than those of the control. However, commodity features and nutritional quality were higher, with rough protein and total amino acids contents 3.8% and 2.7% higher than the control. In terms of food security, no significant difference in pesticide residue and heavy metal toxicity in N. nucifera and T. acornis products between integrated “plant-fish” farming and monocroppong systems was noted.
As an innovative farming system, integrated “plant-fish” farming has since 2010 developed rapidly in the lowland areas of North Zhejiang Province. This region generally lies in very low altitudes. To optimize integrated aquatic vegetable cultivation in “plant-fish” farming systems, a comparative experiment was carried out in two farms. The growth, quality and food security of Nelumbo nucifera and Trapa acornis in different integrated aquaculture farming systems were analyzed. The results showed that the growth and development, commodity feature and quality of N. nucifera improved in integrated “plant-fish” farming systems. Compared with monocropping system of N. nucifera (control), “plant-fish” integrated farming systems increased N. nucifera leaf length, leaf width and petiole length by 1.2%~38.2%, 8.6%~30.9% and 10.1%~33.2%, respectively. Similarly, N. nucifera commodity features improved under integrated “plant-fish” farming systems. Total tuber weight and maximum tuber node weight of N. nucifera in “plant-fish” integrated farming systems increased by 19.0%~77.8% and 22.0%~77.5%, respectively, compared with the control. N. nucifera nutritional quality also improved. N. nucifera contents of starch, protein and total amino acids in “N. nucifera-Pelteobagrus fulvidraco and Misgurnus anguillicaudatus” farming system increased by 34.0%, 47.3% and 48.7%, respectively, compared with the control. Also those in “N. nucifera-Carassius auratus and P. fulvidraco” system were respectively 23.3%, 5.4% and 11.3% higher than those in the control. In “N. nucifera-Ophicephalus argus” system, N. nucifera starch content was 31.1% higher than that in the control. However, the contents of protein and total amino acids decreased respectively by 20.4% and 5.3% over the control. The results also showed that in “T. acornis-Trionyx sinensis” system, growth, development and commodity features of T. acornis increased significantly. T. acornis leaf and phyllome size was larger than that of the control (monocropped T. acornis in fishpond). Also T. acornis fruit fresh weight was 6.2% higher than the control, but contents of rough protein and total amino acids were 16.0% and 17.0% lower than the control. Under “T. acornis-O. argus” farming system, T. acornis growth and development were lower than those of the control. However, commodity features and nutritional quality were higher, with rough protein and total amino acids contents 3.8% and 2.7% higher than the control. In terms of food security, no significant difference in pesticide residue and heavy metal toxicity in N. nucifera and T. acornis products between integrated “plant-fish” farming and monocroppong systems was noted.
2012, 20(12): 1650-1656.
doi: 10.3724/SP.J.1011.2012.01650
Abstract:
There are three reasons for the increasing demand of crop models that build plants on the basis of architectural principles and organogenetic processes. The first of these reasons is that realistic concepts of developing new crops need to be guided by such models. The second is that there is an increasing interest in crop phenotypic plasticity based on variable architecture and morphology. The third reason is that engineering of mechanized cropping systems requires information on crop architecture. Functional-structural plant models (FSPM) are the best bridge to connect the function and structure of plant growth and development, which are the tendency of future plant models. FSPM is a digital tool for crop growth regulation and variety design. With regard to studies on cotton cultivation in China, an explanatory model of cotton growth and development (COTGROW) was developed and modified based on the processes of the GOSSYM cotton model. The COTGROW model included meteorological, soil and other environmental conditions and management practices modules. The objective of this study was to construct a virtual growth model of cotton with eco-physiological processes. Field experiments with different densities of cotton cultivar "NuCoTN 33B" were conducted for 2008-2010 in Anyang (36°07?N, 114°22?E) of Henan Province, China. The experiment included five planting densities (plants·m-2): 1.5, 3.3, 5.1, 6.9 and 8.7. Plants were sown on 18 April in 2008 (Exp. 2008), 26 April in 2009 (Exp. 2009) and 29 April (Exp. 2010). Each treatment had three replications in a randomized complete block design. Five plants were collected for each replication at the sampling dates. The soil was a sandy clay-loam, previously managed as meadow land. The plots were irrigated and fertilized to avoid nutrient and water limitations to plant growth. Weeds were removed by hand to avoid herbicide effects on the plant growth. No plant disease, pest or stress symptoms were observed. Detailed observations were made on the dimensions and biomass of above-ground plant organs for each phytomer throughout the seasons. Growth stage-specific target files (a description of plant part weight and dimension based on plant topological structure) were established from the measured data. The relationship between biomass and morphology of the above-ground cotton plant parts was analyzed and used to establish a cotton simulation model for above-ground parts. This algorithm improved the development and morphogenesis modules in COTGROW. A preliminary model calibration was carried out using the experimental data for 2008 and 2009, and the model was validated using independent experimental data for 2010. The results showed that the simulated values agreed well with the measured ones. Correlation coefficient (R) and root mean squared error (RMSE) between the measured and simulated values of morphological parameters were determined. The determined R for plant height, main stem node number, fruiting branch number, fruiting branch node number, internode length, internode diameter, leaf blade length, leaf blade width, petiole length, petiole diameter, boll length and boll diameter were 0.99, 0.99, 0.99, 0.92, 0.95, 0.93, 0.75, 0.71, 0.81, 0.62, 0.98 and 0.98, respectively. The corresponding determined RMSE for the above parameters were 3.85 cm, 0.64, 0.52, 0.66, 1.00 cm, 0.15 cm, 1.58 cm, 2.39 cm, 2.54 cm, 0.05 cm, 0.13 cm and 0.10 cm, respectively. The results indicated that the model achieved a good performance in simulating the growth processes of the above-ground parts of cotton plant. It was further possible to build a visual plant model from the above model.
There are three reasons for the increasing demand of crop models that build plants on the basis of architectural principles and organogenetic processes. The first of these reasons is that realistic concepts of developing new crops need to be guided by such models. The second is that there is an increasing interest in crop phenotypic plasticity based on variable architecture and morphology. The third reason is that engineering of mechanized cropping systems requires information on crop architecture. Functional-structural plant models (FSPM) are the best bridge to connect the function and structure of plant growth and development, which are the tendency of future plant models. FSPM is a digital tool for crop growth regulation and variety design. With regard to studies on cotton cultivation in China, an explanatory model of cotton growth and development (COTGROW) was developed and modified based on the processes of the GOSSYM cotton model. The COTGROW model included meteorological, soil and other environmental conditions and management practices modules. The objective of this study was to construct a virtual growth model of cotton with eco-physiological processes. Field experiments with different densities of cotton cultivar "NuCoTN 33B" were conducted for 2008-2010 in Anyang (36°07?N, 114°22?E) of Henan Province, China. The experiment included five planting densities (plants·m-2): 1.5, 3.3, 5.1, 6.9 and 8.7. Plants were sown on 18 April in 2008 (Exp. 2008), 26 April in 2009 (Exp. 2009) and 29 April (Exp. 2010). Each treatment had three replications in a randomized complete block design. Five plants were collected for each replication at the sampling dates. The soil was a sandy clay-loam, previously managed as meadow land. The plots were irrigated and fertilized to avoid nutrient and water limitations to plant growth. Weeds were removed by hand to avoid herbicide effects on the plant growth. No plant disease, pest or stress symptoms were observed. Detailed observations were made on the dimensions and biomass of above-ground plant organs for each phytomer throughout the seasons. Growth stage-specific target files (a description of plant part weight and dimension based on plant topological structure) were established from the measured data. The relationship between biomass and morphology of the above-ground cotton plant parts was analyzed and used to establish a cotton simulation model for above-ground parts. This algorithm improved the development and morphogenesis modules in COTGROW. A preliminary model calibration was carried out using the experimental data for 2008 and 2009, and the model was validated using independent experimental data for 2010. The results showed that the simulated values agreed well with the measured ones. Correlation coefficient (R) and root mean squared error (RMSE) between the measured and simulated values of morphological parameters were determined. The determined R for plant height, main stem node number, fruiting branch number, fruiting branch node number, internode length, internode diameter, leaf blade length, leaf blade width, petiole length, petiole diameter, boll length and boll diameter were 0.99, 0.99, 0.99, 0.92, 0.95, 0.93, 0.75, 0.71, 0.81, 0.62, 0.98 and 0.98, respectively. The corresponding determined RMSE for the above parameters were 3.85 cm, 0.64, 0.52, 0.66, 1.00 cm, 0.15 cm, 1.58 cm, 2.39 cm, 2.54 cm, 0.05 cm, 0.13 cm and 0.10 cm, respectively. The results indicated that the model achieved a good performance in simulating the growth processes of the above-ground parts of cotton plant. It was further possible to build a visual plant model from the above model.
2012, 20(12): 1657-1663.
doi: 10.3724/SP.J.1011.2012.01657
Abstract:
Multiple cropping index (MCI), which is an index for characterizing cropping systems, reflects the degree of arable land available for use at a certain period. It is a significant index for evaluating food production and security and making decisions on agricultural development plans. This is especially useful for China, a country with a large population and smell per-capita arable land. There are two methods (statistical method and remote sensing-based method) for extracting MCI. The second method usually uses Normalized Difference Vegetation Index (NDVI) as source data. NDVI time series for the year can describe the dynamic process of vegetation. For crop, these processes include seeding, jointing, tasseling, harvesting, and so on. Generally, the peak of NDVI time series curves corresponds with tasseling and the lowest point corresponds with harvesting or seeding. Croplands with one crop per year have only one peak and croplands with two crops per year have two peaks. As MCI value matches with the number of peaks of NDVI time series, MCI is extractible from NDVI time series data. In relation to traditional statistical methods, a method based on NDVI time series does not only reflect spatial distribution of MCI, but also easily converge to rapidly provide results. Due to cloud contamination, however, NDVI time series from remote sensing data contain a lot of noise. NDVI data must be preprocessed to remove or reduce noise before extracting for MCI. In this study, the SPLINE interpolation method was used to produce cloud free time series of NDVI to avoid pseudo peaks and accurately extracts MCI from NDVI time series, although not without some limitations. Bohai Rim, an important production base in China, was used as the case-study area in this study. NDVI time series derived from MODIS data were used to extract MCI. MCI for 2000-2009 was extracted and temporal and spatial changes over the Bohai Rim were analyzed. The results showed that croplands in the Bohai Rim with two crops per year mainly occurred in the south of the Great Wall. Other regions of the Bohai Rim were dominated by croplands with one crop per year. The highest MCI was in Shandong Province, where the 10-year mean of MCI was 140.40%. MCI was lowest in Liaoning Province, where natural conditions such as heat were not conducive for producing two crops per year. The 10-year means of MCI for Hebei Province, Tianjin City and Beijing City were 129.65%, 109.52% and 106.13%, respectively. The 10-year mean of MCI for the entire Bohai Rim study area was 117.14%. MCI was also different for different topographic conditions. The mean MCI values for plain, mesa, hill and mountain regions were 154.78%, 117.18%, 109.99% and 103.52%, respectively. In the Bohai Rim, there were obvious inter-annual variations in MCI but with no obvious trends. The maximum MCI was in 2000, while the minimum was in 2009. Inter-annual variation in MCI was mainly influenced by crop rotation and net income from croplands. The existence of mixed pixels affected the accuracy of the extracted MCI based on remote sensing data.
Multiple cropping index (MCI), which is an index for characterizing cropping systems, reflects the degree of arable land available for use at a certain period. It is a significant index for evaluating food production and security and making decisions on agricultural development plans. This is especially useful for China, a country with a large population and smell per-capita arable land. There are two methods (statistical method and remote sensing-based method) for extracting MCI. The second method usually uses Normalized Difference Vegetation Index (NDVI) as source data. NDVI time series for the year can describe the dynamic process of vegetation. For crop, these processes include seeding, jointing, tasseling, harvesting, and so on. Generally, the peak of NDVI time series curves corresponds with tasseling and the lowest point corresponds with harvesting or seeding. Croplands with one crop per year have only one peak and croplands with two crops per year have two peaks. As MCI value matches with the number of peaks of NDVI time series, MCI is extractible from NDVI time series data. In relation to traditional statistical methods, a method based on NDVI time series does not only reflect spatial distribution of MCI, but also easily converge to rapidly provide results. Due to cloud contamination, however, NDVI time series from remote sensing data contain a lot of noise. NDVI data must be preprocessed to remove or reduce noise before extracting for MCI. In this study, the SPLINE interpolation method was used to produce cloud free time series of NDVI to avoid pseudo peaks and accurately extracts MCI from NDVI time series, although not without some limitations. Bohai Rim, an important production base in China, was used as the case-study area in this study. NDVI time series derived from MODIS data were used to extract MCI. MCI for 2000-2009 was extracted and temporal and spatial changes over the Bohai Rim were analyzed. The results showed that croplands in the Bohai Rim with two crops per year mainly occurred in the south of the Great Wall. Other regions of the Bohai Rim were dominated by croplands with one crop per year. The highest MCI was in Shandong Province, where the 10-year mean of MCI was 140.40%. MCI was lowest in Liaoning Province, where natural conditions such as heat were not conducive for producing two crops per year. The 10-year means of MCI for Hebei Province, Tianjin City and Beijing City were 129.65%, 109.52% and 106.13%, respectively. The 10-year mean of MCI for the entire Bohai Rim study area was 117.14%. MCI was also different for different topographic conditions. The mean MCI values for plain, mesa, hill and mountain regions were 154.78%, 117.18%, 109.99% and 103.52%, respectively. In the Bohai Rim, there were obvious inter-annual variations in MCI but with no obvious trends. The maximum MCI was in 2000, while the minimum was in 2009. Inter-annual variation in MCI was mainly influenced by crop rotation and net income from croplands. The existence of mixed pixels affected the accuracy of the extracted MCI based on remote sensing data.
2012, 20(12): 1664-1672.
doi: 10.3724/SP.J.1011.2012.01664
Abstract:
Subsurface pipe drainage system is an efficient engineering approach to improve saline-alkali lands. It runs by controlling water tables to certain levels while leaching salt by rain-fed or irrigated water. Subsurface pipe drainage system changes the velocity, quantity and direction of soil water and salt movement. This induces soil salt redistribution and variations in soil features. This paper firstly summarized the technological development of subsurface pipe drainage system, discussed the conditions (natural and ecological) of application and the key engineering parameters. Based on literature analysis, the mechanism and response of agro-ecosystems to subsurface pipe drainage system regarding improving saline-alkali lands were then presented. Numerous research on the mechanism of subsurface pipe drainage systems had mainly focused on: 1) changes in circulation principles of precipitation, surface water, soil water and groundwater, especially the relationship between agriculture and water table level, irrigation system, waterlogging. 2) The features of soil water and salt migration under controlled and fixed water table drainage. Under controlled drainage conditions, soil salt varied with drainage frequency and intensity at supportable soil water content. Under fixed water table drainage conditions, the depth of subsurface pipe and the spacing between side-by-side pipes regulated drainage water and salt movements. 3) Simulated and modeled soil water and salt migration features. These researches focused on the theoretical innovation, key parameters determination, validation and suitability. Also research on agro-ecosystem response had mainly focused on: 1) soil features in ago-ecosystems; 2) adaptable crop planting, including physiological and ecological responses of crop growth, quality and yield to subsurface pipe drainage system; and on 3) agro-ecosystem structure and functional responses, including tillage system, land use and ecosystem services promotion. Finally, this paper put forward two strategies of future research on subsurface pipe drainage systems and applications.
Subsurface pipe drainage system is an efficient engineering approach to improve saline-alkali lands. It runs by controlling water tables to certain levels while leaching salt by rain-fed or irrigated water. Subsurface pipe drainage system changes the velocity, quantity and direction of soil water and salt movement. This induces soil salt redistribution and variations in soil features. This paper firstly summarized the technological development of subsurface pipe drainage system, discussed the conditions (natural and ecological) of application and the key engineering parameters. Based on literature analysis, the mechanism and response of agro-ecosystems to subsurface pipe drainage system regarding improving saline-alkali lands were then presented. Numerous research on the mechanism of subsurface pipe drainage systems had mainly focused on: 1) changes in circulation principles of precipitation, surface water, soil water and groundwater, especially the relationship between agriculture and water table level, irrigation system, waterlogging. 2) The features of soil water and salt migration under controlled and fixed water table drainage. Under controlled drainage conditions, soil salt varied with drainage frequency and intensity at supportable soil water content. Under fixed water table drainage conditions, the depth of subsurface pipe and the spacing between side-by-side pipes regulated drainage water and salt movements. 3) Simulated and modeled soil water and salt migration features. These researches focused on the theoretical innovation, key parameters determination, validation and suitability. Also research on agro-ecosystem response had mainly focused on: 1) soil features in ago-ecosystems; 2) adaptable crop planting, including physiological and ecological responses of crop growth, quality and yield to subsurface pipe drainage system; and on 3) agro-ecosystem structure and functional responses, including tillage system, land use and ecosystem services promotion. Finally, this paper put forward two strategies of future research on subsurface pipe drainage systems and applications.
2012, 20(12): 1673-1679.
doi: 10.3724/SP.J.1011.2012.01673
Abstract:
About 8.6×105 hm2 saline/alkaline lands exist in the coastal areas of Hebei Province. Soil salinity in the coastal areas of Hebei Province has mainly been caused by shallow groundwater table and highly saline groundwater. Remedial solutions to soil salinity/alkalinity were by deepening water tables in the region. Subsurface pipe drainage system has proved effective in deepening water tables in the coastal areas of Hebei Province. To research into the effects of subsurface pipe drainage system on soil salinity/alkalinity in the coastal areas of Hebei Province, regions suitable for application of subsurface pipe drainage system were delineated. The research analyzed the limiting conditions of subsurface pipe drainage system application. The superposition and other analyses were executed in ArcGIS environment. The aim of subsurface pipe drainage system was to reduce soil salinity/alkalinity and increase the fertility of saline/alkaline lands. As the coastal areas of Hebei Province is an important grain production region, it is critical to study the effects of subsurface pipe drainage system on optimizing land output. In the paper, the summer maize-winter wheat, foxtail millet-winter wheat and monoculture cotton cropping systems were analyzed. Haixing County, a county with typical saline/alkali soils, was selected as the study area to calculate the changes in ecological services value (ESV) caused by the use of subsurface pipe drainage system. The results were as follows: 1) the region suitable for the application of subsurface pipe drainage system was 3.90×105 hm2. In the 3.90×105 hm2, the areas of original arable lands, ditches and wastelands were 3.21 ×105 hm2, 5.14×104 hm2 and 1.76×104 hm2, respectively. So the new arable land area after subsurface pipe drainage system application was 6.90×104 hm2. (2) Based on arable land area after subsurface pipe drainage system application and real cultivation area ratios of different crops, yield of summer maize-winter wheat increased by 4.82×108 kg, yield of foxtail millet-winter wheat increased by 1.29×108 kg and yield of monoculture cotton increased by 3.67×108 kg. (3) In Haixing County, ESV increased by 3.90×109 Yuan·a 1 after application of subsurface pipe drainage system. On average, ESV increased by 4.06×104 Yuan·hm-2·a-1.
About 8.6×105 hm2 saline/alkaline lands exist in the coastal areas of Hebei Province. Soil salinity in the coastal areas of Hebei Province has mainly been caused by shallow groundwater table and highly saline groundwater. Remedial solutions to soil salinity/alkalinity were by deepening water tables in the region. Subsurface pipe drainage system has proved effective in deepening water tables in the coastal areas of Hebei Province. To research into the effects of subsurface pipe drainage system on soil salinity/alkalinity in the coastal areas of Hebei Province, regions suitable for application of subsurface pipe drainage system were delineated. The research analyzed the limiting conditions of subsurface pipe drainage system application. The superposition and other analyses were executed in ArcGIS environment. The aim of subsurface pipe drainage system was to reduce soil salinity/alkalinity and increase the fertility of saline/alkaline lands. As the coastal areas of Hebei Province is an important grain production region, it is critical to study the effects of subsurface pipe drainage system on optimizing land output. In the paper, the summer maize-winter wheat, foxtail millet-winter wheat and monoculture cotton cropping systems were analyzed. Haixing County, a county with typical saline/alkali soils, was selected as the study area to calculate the changes in ecological services value (ESV) caused by the use of subsurface pipe drainage system. The results were as follows: 1) the region suitable for the application of subsurface pipe drainage system was 3.90×105 hm2. In the 3.90×105 hm2, the areas of original arable lands, ditches and wastelands were 3.21 ×105 hm2, 5.14×104 hm2 and 1.76×104 hm2, respectively. So the new arable land area after subsurface pipe drainage system application was 6.90×104 hm2. (2) Based on arable land area after subsurface pipe drainage system application and real cultivation area ratios of different crops, yield of summer maize-winter wheat increased by 4.82×108 kg, yield of foxtail millet-winter wheat increased by 1.29×108 kg and yield of monoculture cotton increased by 3.67×108 kg. (3) In Haixing County, ESV increased by 3.90×109 Yuan·a 1 after application of subsurface pipe drainage system. On average, ESV increased by 4.06×104 Yuan·hm-2·a-1.
2012, 20(12): 1680-1686.
doi: 10.3724/SP.J.1011.2012.01680
Abstract:
Coastal saline-alkali soils form a critical component of the abundant saline soils in China. Shallow groundwater, highly saline soils and strong seasonal changes in soil water and salt are the main characteristics of saline coastal plains in East Hebei Province. Given these characteristics, salt stress, drought and water logging have been the main limiting factors to crop production in this area. This study summarized the principles and implementation of various farmland eco-engineering methods to overcome these limiting factors. It studied the improvements in saline soils via eco-engineering using sensitivity analysis of three kinds of stresses in local common crops in Nandagang. The results of the field experiment showed that yields of cotton and maize were respectively 2.23~3.98 t·hm-2 and 4.6~6.7 t·hm-2, which were close to the average level for local farmlands. Total wheat-corn yield at harvest was 9.6~10.8 t·hm-2 and the yield of wheat-millet reached 9.1~11.9 t·hm -2. Farmland eco-engineering significantly increased the suitability land for cropping and multiple crop rotation systems. However, single eco-engineering technology showed some limitations, for example, iced salt-water irrigation increased soil salinity and underground pipe system reduced soil nutrient content and effectiveness. Eco-engineered farmlands were systematic and circulative so that it enhanced redistribution of soil water, reduced soil salt content and prevented salt/water stress. However, there was still the need for more functional technologies to adjust crop to environment for optimal yield. Eco-engineering aimed at producing high crop yields and balanced soil salt content. For that purpose, underground pipe systems replaced the open-ditch systems as the basis of drainage and eco-engineering. Furthermore, eco-engineering was gradually becoming abundant, systematic in the saline-alkaline farmlands of East Hebei Province.
Coastal saline-alkali soils form a critical component of the abundant saline soils in China. Shallow groundwater, highly saline soils and strong seasonal changes in soil water and salt are the main characteristics of saline coastal plains in East Hebei Province. Given these characteristics, salt stress, drought and water logging have been the main limiting factors to crop production in this area. This study summarized the principles and implementation of various farmland eco-engineering methods to overcome these limiting factors. It studied the improvements in saline soils via eco-engineering using sensitivity analysis of three kinds of stresses in local common crops in Nandagang. The results of the field experiment showed that yields of cotton and maize were respectively 2.23~3.98 t·hm-2 and 4.6~6.7 t·hm-2, which were close to the average level for local farmlands. Total wheat-corn yield at harvest was 9.6~10.8 t·hm-2 and the yield of wheat-millet reached 9.1~11.9 t·hm -2. Farmland eco-engineering significantly increased the suitability land for cropping and multiple crop rotation systems. However, single eco-engineering technology showed some limitations, for example, iced salt-water irrigation increased soil salinity and underground pipe system reduced soil nutrient content and effectiveness. Eco-engineered farmlands were systematic and circulative so that it enhanced redistribution of soil water, reduced soil salt content and prevented salt/water stress. However, there was still the need for more functional technologies to adjust crop to environment for optimal yield. Eco-engineering aimed at producing high crop yields and balanced soil salt content. For that purpose, underground pipe systems replaced the open-ditch systems as the basis of drainage and eco-engineering. Furthermore, eco-engineering was gradually becoming abundant, systematic in the saline-alkaline farmlands of East Hebei Province.
2012, 20(12): 1687-1692.
doi: 10.3724/SP.J.1011.2012.01687
Abstract:
Agricultural subsurface drainage is an important measure for preventing waterlogging disaster, reducing soil salinity and promoting crop growth in coastal saline areas. This study was conducted in the coastal saline area of Cangzhou City, Hebei Province. The DRAINMOD model was used to simulate the changes of groundwater depths under subsurface drainage system (drain depth was 1.2 m deep and drain spacing 30 m) for the period from June to September of 2011. Groundwater depth changes under subsurface drainage system with different controlled drainage schemes were also predicted. The DRAINMOD model parameters included soil property data, climatological data, crop data and drainage system parameters. The parameters were collected either in laboratory or field observations. Based on the simulation results, the coefficient of efficiency of the model was 0.67, with a relative error of 6.15%, which showed that the DRAINMOD model simulation was reasonably favorable. The study showed that agro-subsurface drainage systems obviously reduced the occurrence of waterlogging. Water table depths were controlled to below 60 cm in 2 days by the subsurface drainage system. Also groundwater table depths were controlled to below 60 cm in 15 days in filed without subsurface drainage system. Four drainage schemes (natural drainage, controlling groundwater depth to 50 cm, 80 cm and 100 cm) were designed and the simulations indicated that it was appropriate to control water table depths to below 80 cm at low cost and no waterlogging. In conclusion, the DRAINMOD model proved to perform well for the hydrology of agro-surface drainage systems and was therefore a useful tool for designing drainage and water management systems. Thus the DRAINMOD model was as well usable in simulating future groundwater table depths in saline coastal areas. It then provided better solutions for subsurface drainage system optimization and water management selection.
Agricultural subsurface drainage is an important measure for preventing waterlogging disaster, reducing soil salinity and promoting crop growth in coastal saline areas. This study was conducted in the coastal saline area of Cangzhou City, Hebei Province. The DRAINMOD model was used to simulate the changes of groundwater depths under subsurface drainage system (drain depth was 1.2 m deep and drain spacing 30 m) for the period from June to September of 2011. Groundwater depth changes under subsurface drainage system with different controlled drainage schemes were also predicted. The DRAINMOD model parameters included soil property data, climatological data, crop data and drainage system parameters. The parameters were collected either in laboratory or field observations. Based on the simulation results, the coefficient of efficiency of the model was 0.67, with a relative error of 6.15%, which showed that the DRAINMOD model simulation was reasonably favorable. The study showed that agro-subsurface drainage systems obviously reduced the occurrence of waterlogging. Water table depths were controlled to below 60 cm in 2 days by the subsurface drainage system. Also groundwater table depths were controlled to below 60 cm in 15 days in filed without subsurface drainage system. Four drainage schemes (natural drainage, controlling groundwater depth to 50 cm, 80 cm and 100 cm) were designed and the simulations indicated that it was appropriate to control water table depths to below 80 cm at low cost and no waterlogging. In conclusion, the DRAINMOD model proved to perform well for the hydrology of agro-surface drainage systems and was therefore a useful tool for designing drainage and water management systems. Thus the DRAINMOD model was as well usable in simulating future groundwater table depths in saline coastal areas. It then provided better solutions for subsurface drainage system optimization and water management selection.
2012, 20(12): 1693-1699.
doi: 10.3724/SP.J.1011.2012.01693
Abstract:
To explore the application of subsurface pipe drainage technology in saline-alkali coastal areas of Hebei Province, key parameters of the drainage method (pipe depth and spacing) were tested in a farm field experiment in Nandagang, Hebei Province. Five treatments considered in the study included open-ditch drainage treatment (CK1, CK2) and 4 subsurface pipe drainage treatments (T1, T2, T3 and T4) with respectively 1.0 m/20 m, 1.2 m/30 m, 1.4 m/40 m and 1.6 m/50 m pipe depth/spacing. Groundwater depth, soil salinity, subsurface pipe optimal parameters and movement mechanisms of water and salt (e.g., salt ion component changes) were analyzed in the one-year experiment. The conclusions of the experiment were as follows: (1) Subsurface pipe drainage technology effectively controlled groundwater level, enhanced salt leaching by precipitation, lowered groundwater level and thereby prevented salt accumulation in surface soils. Subsurface pipe drainage technology was therefore suitable for application in saline-alkali coastal areas of Hebei Province with shallow groundwater levels. (2) In comparison to open-ditch drainage treatment, subsurface pipe drainage had better capacity to prevent water-logging disasters and reduced by 70% water-logging hazards during the rainy season. (3) Subsurface drainage technology significantly reduced salt content in arable soil layers (0~20 cm) by an average of 1.1‰ or even up to 1.8‰ during salt sensitive periods under cotton cultivation. (4) Considering the average decline and restoration rates of groundwater level and the economic cost of laying underground pipes, T2 treatment (with buried pipe depth of 1.2 m and spacing of 30 m) was the most optimal scheme for saline-alkali coastal areas of Hebei Province. (5) The migration rates of salt ions along with soil water movement were different in different soil types. Chloride ion migration rate was the fastest, followed by that of calcium ion.
To explore the application of subsurface pipe drainage technology in saline-alkali coastal areas of Hebei Province, key parameters of the drainage method (pipe depth and spacing) were tested in a farm field experiment in Nandagang, Hebei Province. Five treatments considered in the study included open-ditch drainage treatment (CK1, CK2) and 4 subsurface pipe drainage treatments (T1, T2, T3 and T4) with respectively 1.0 m/20 m, 1.2 m/30 m, 1.4 m/40 m and 1.6 m/50 m pipe depth/spacing. Groundwater depth, soil salinity, subsurface pipe optimal parameters and movement mechanisms of water and salt (e.g., salt ion component changes) were analyzed in the one-year experiment. The conclusions of the experiment were as follows: (1) Subsurface pipe drainage technology effectively controlled groundwater level, enhanced salt leaching by precipitation, lowered groundwater level and thereby prevented salt accumulation in surface soils. Subsurface pipe drainage technology was therefore suitable for application in saline-alkali coastal areas of Hebei Province with shallow groundwater levels. (2) In comparison to open-ditch drainage treatment, subsurface pipe drainage had better capacity to prevent water-logging disasters and reduced by 70% water-logging hazards during the rainy season. (3) Subsurface drainage technology significantly reduced salt content in arable soil layers (0~20 cm) by an average of 1.1‰ or even up to 1.8‰ during salt sensitive periods under cotton cultivation. (4) Considering the average decline and restoration rates of groundwater level and the economic cost of laying underground pipes, T2 treatment (with buried pipe depth of 1.2 m and spacing of 30 m) was the most optimal scheme for saline-alkali coastal areas of Hebei Province. (5) The migration rates of salt ions along with soil water movement were different in different soil types. Chloride ion migration rate was the fastest, followed by that of calcium ion.
WANG Wen-Hui,
LIU Hui-Tao,
MA Feng-Jiao,
HAN Li-Pu,
LIU Peng,
XU Li,
TAN Li-Mei,
YU Shu-Hui,
LIU Jin-Tong
2012, 20(12): 1700-1705.
doi: 10.3724/SP.J.1011.2012.01700
Abstract:
Soil salinity is a major environmental problem in China. In recent years, several related organizations and researchers sought to reduce soil salinity/alkalinity. For example, the subsurface pipe drainage system is a physical method used to reduce soil salinity and alkalinity in the coastal saline regions of Hebei Province. It was then critical to determine the degree to which soil salinity/alkalinity was reduced under this physical method. The distribution and diversity of halophyte communities in coastal saline regions have been impacted by soil salinity. As halophyte communities presented regional differences, they constituted a possible useful indicator for determining the degree of soil salinity. Thus this research on halophyte resources, community types, characteristics and distribution not only supplemented and improved evaluation methods of soil salinity reduction techniques, but also provided a guiding sense to soil salinity/alkalinity as a way of improving local land/ecological environmental management. This paper used the subsurface pipe drainage system region in Huanghua City, Hebei Province, where there had existed chronic soil salinity. In August 2012, a 5-point sampling method was used to investigate halophytic vegetations under 4 different habitats in the study area. The habitats included wasteland with subsurface drainage system, summer fallow land with subsurface drainage system, wasteland without subsurface drainage system and summer fallow land without subsurface drainage system. Then a hierarchical cluster analysis based on key values of the plant population and several diversity indices (e.g., Shannon-Wiener index, Pielou index, and Simpson index) were used to analyze vegetation community type and composition in the area. The study also analyzed the differences in vegetation community characteristics and distributions among the 4 different habitats. The results of the study were that in the 20 sampling plots, a total of 19 species existed. The 19 species belonged to 8 families and 17 genera, and the vegetation was classified into 5 communities. Through analysis of the differences in vegetation community characteristics and distributions among the 4 different habitats, it was concluded that community composition of both wasteland and fallow land changed from usual euhalophyte to pseudohalophyte and then to non-halophyte vegetation after application of subsurface pipe drainage system. The Shannon-Wiener index and Pielou index of wasteland and summer fallow-land vegetation with subsurface pipe drainage system were higher than those without subsurface pipe drainage system. The study therefore showed that habitats with subsurface pipe drainage system had higher species diversity index and community evenness than those without subsurface pipe drainage system. The results indicated that the use of subsurface pipe drainage system was an effective method in reducing soil salinity and improving biological diversity. It was recommended to continue research and application of subsurface pipe drainage system to improve the fertility of saline/alkaline lands.
Soil salinity is a major environmental problem in China. In recent years, several related organizations and researchers sought to reduce soil salinity/alkalinity. For example, the subsurface pipe drainage system is a physical method used to reduce soil salinity and alkalinity in the coastal saline regions of Hebei Province. It was then critical to determine the degree to which soil salinity/alkalinity was reduced under this physical method. The distribution and diversity of halophyte communities in coastal saline regions have been impacted by soil salinity. As halophyte communities presented regional differences, they constituted a possible useful indicator for determining the degree of soil salinity. Thus this research on halophyte resources, community types, characteristics and distribution not only supplemented and improved evaluation methods of soil salinity reduction techniques, but also provided a guiding sense to soil salinity/alkalinity as a way of improving local land/ecological environmental management. This paper used the subsurface pipe drainage system region in Huanghua City, Hebei Province, where there had existed chronic soil salinity. In August 2012, a 5-point sampling method was used to investigate halophytic vegetations under 4 different habitats in the study area. The habitats included wasteland with subsurface drainage system, summer fallow land with subsurface drainage system, wasteland without subsurface drainage system and summer fallow land without subsurface drainage system. Then a hierarchical cluster analysis based on key values of the plant population and several diversity indices (e.g., Shannon-Wiener index, Pielou index, and Simpson index) were used to analyze vegetation community type and composition in the area. The study also analyzed the differences in vegetation community characteristics and distributions among the 4 different habitats. The results of the study were that in the 20 sampling plots, a total of 19 species existed. The 19 species belonged to 8 families and 17 genera, and the vegetation was classified into 5 communities. Through analysis of the differences in vegetation community characteristics and distributions among the 4 different habitats, it was concluded that community composition of both wasteland and fallow land changed from usual euhalophyte to pseudohalophyte and then to non-halophyte vegetation after application of subsurface pipe drainage system. The Shannon-Wiener index and Pielou index of wasteland and summer fallow-land vegetation with subsurface pipe drainage system were higher than those without subsurface pipe drainage system. The study therefore showed that habitats with subsurface pipe drainage system had higher species diversity index and community evenness than those without subsurface pipe drainage system. The results indicated that the use of subsurface pipe drainage system was an effective method in reducing soil salinity and improving biological diversity. It was recommended to continue research and application of subsurface pipe drainage system to improve the fertility of saline/alkaline lands.
2012, 20(12): 1706-1712.
doi: 10.3724/SP.J.1011.2012.01706
Abstract:
Because oat is highly nutritious and resistant to drought, barren and saline conditions, it is extensively cultivated around world. However, there is less oat cultivation in low-latitude coastal saline areas. Therefore the absorption of soil salt ions and the potential for improvement of saline-alkali soils via oat cultivation has been rarely researched. To investigate the characteristics of straw salt accumulation and the potential for improving saline-alkali soils via oat cultivation in coastal Hebei Province, the single factor randomized block design experiments of two factors (variety and soil salinity) was analyzed for oat biomass, straw ion concentration and accumulation, and straw-soil ion concentration ratio. The results showed that variety "Bayou1" oat biomass was 2.9 t·hm-2 at flowering-filling stage, which increased to 3.8 t·hm -2 at maturity. When "Bayou1" oat harvest was delayed for 20 days, biomass yield decreased to 2.5 t·hm -2. "Baiyan2" oat biomass was 3.1 t·hm -2 in low saline soils (containing 1.0 g·kg -1 salt), which was significantly greater than in medium (1.7 t·hm-2) and high (0.4 t·hm-2) saline soils (containing 2.0 g·kg-1 and 3.0 g·kg-1 salt, re-spectively). Under the medium salinity conditions, "Bayou1" biomass (3.8 t·hm-2) was significantly higher than "Baiyan2" (3.1 t·hm-2) and "Huazao2" (2.2 t·hm -2) biomass. Na+ and K+concentrations in "Bayou1" straw from flowering to maturity stage significantly increased, while Mg2+, Ca2+ and Cl decreased. When oat harvest was delayed, straw ion concentration (with the excepting of Ca2+) significantly dropped. Na+, Mg2+, Ca2+ and Cl in "Baiyan2" straw significantly increased with increasing soil salinity, whild K+ significantly decreased. There were significant differences in Na+, K+ and Mg2+ concentrations among the three oat varieties, but no notable differences in Ca2+ and Cl . Cl concentration was highest in the oat straws, followed by K++Na+, Mg2+, Ca2+, Na+, K+, Mg2+and Cl accumulations in "Bayou1" straw were highest at maturity, which significantly dropped under delayed harvest. Na+, K+, Mg2+, Ca2+ and Cl accumulations in "Baiyan2" dropped with soil salinity increasing. With the exception of Ca2+, there were significant differences in straws Na+, K+, Mg2+ and Cl accumulations among the three oat varieties. For "Bayou1" straw-soil ion concentration ratio, Na++K+ was highest (with ratio of 46~63), followed by Cl (30~46), Mg2+ (24~30) and Ca2+ (3~15). With the exception of Mg2+ and Ca2+, the ratios dropped significantly when oat harvests were delayed. With soil salinity increasing, Na++K+ and Cl ratios of oat-straw to soil significantly dropped, Ca2+ ratio changed unsignificantly. There were significant differences in straw-soil ion ratios among the oat varieties. The oat had the potential for improving saline-alkali soils in theory, but harvest time and soil salinity significantly affected oat biomass, ion concentration and accumulation. Furtherly, the influences of application of subsurface drainage system on topsoil salt balance and the effect of drought on oat salt accumulation during the oat growth season needed further research.
Because oat is highly nutritious and resistant to drought, barren and saline conditions, it is extensively cultivated around world. However, there is less oat cultivation in low-latitude coastal saline areas. Therefore the absorption of soil salt ions and the potential for improvement of saline-alkali soils via oat cultivation has been rarely researched. To investigate the characteristics of straw salt accumulation and the potential for improving saline-alkali soils via oat cultivation in coastal Hebei Province, the single factor randomized block design experiments of two factors (variety and soil salinity) was analyzed for oat biomass, straw ion concentration and accumulation, and straw-soil ion concentration ratio. The results showed that variety "Bayou1" oat biomass was 2.9 t·hm-2 at flowering-filling stage, which increased to 3.8 t·hm -2 at maturity. When "Bayou1" oat harvest was delayed for 20 days, biomass yield decreased to 2.5 t·hm -2. "Baiyan2" oat biomass was 3.1 t·hm -2 in low saline soils (containing 1.0 g·kg -1 salt), which was significantly greater than in medium (1.7 t·hm-2) and high (0.4 t·hm-2) saline soils (containing 2.0 g·kg-1 and 3.0 g·kg-1 salt, re-spectively). Under the medium salinity conditions, "Bayou1" biomass (3.8 t·hm-2) was significantly higher than "Baiyan2" (3.1 t·hm-2) and "Huazao2" (2.2 t·hm -2) biomass. Na+ and K+concentrations in "Bayou1" straw from flowering to maturity stage significantly increased, while Mg2+, Ca2+ and Cl decreased. When oat harvest was delayed, straw ion concentration (with the excepting of Ca2+) significantly dropped. Na+, Mg2+, Ca2+ and Cl in "Baiyan2" straw significantly increased with increasing soil salinity, whild K+ significantly decreased. There were significant differences in Na+, K+ and Mg2+ concentrations among the three oat varieties, but no notable differences in Ca2+ and Cl . Cl concentration was highest in the oat straws, followed by K++Na+, Mg2+, Ca2+, Na+, K+, Mg2+and Cl accumulations in "Bayou1" straw were highest at maturity, which significantly dropped under delayed harvest. Na+, K+, Mg2+, Ca2+ and Cl accumulations in "Baiyan2" dropped with soil salinity increasing. With the exception of Ca2+, there were significant differences in straws Na+, K+, Mg2+ and Cl accumulations among the three oat varieties. For "Bayou1" straw-soil ion concentration ratio, Na++K+ was highest (with ratio of 46~63), followed by Cl (30~46), Mg2+ (24~30) and Ca2+ (3~15). With the exception of Mg2+ and Ca2+, the ratios dropped significantly when oat harvests were delayed. With soil salinity increasing, Na++K+ and Cl ratios of oat-straw to soil significantly dropped, Ca2+ ratio changed unsignificantly. There were significant differences in straw-soil ion ratios among the oat varieties. The oat had the potential for improving saline-alkali soils in theory, but harvest time and soil salinity significantly affected oat biomass, ion concentration and accumulation. Furtherly, the influences of application of subsurface drainage system on topsoil salt balance and the effect of drought on oat salt accumulation during the oat growth season needed further research.
Editor-in-chief：LIU Changming
Competent Authorities：Chinese Academy of Sciences
Sponsored by：Institute of Genetics and Developmental Biology, Chinese Academy of Sciences; China Ecological Economics Society
Organizer：Center for Agricultural Resources Research, Institute of Genetics and Developmental Biology, Chinese Academy of Sciences
ISSN 2096-6237
CN 13-1432/S
- Chinese core periodicals
- Core Chinese Sci-Tech Periodicals
- China's Top Science and Technology Periodicals
- Covered by Chinese Science Citation Database (CSCD)
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