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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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2016 Vol. 24, No. 3
Display Method:
2016, 24(3): 265-273.
Abstract:
Interspecific relationship is an important biological basis for high-yield and efficient utilization of resources in intercropping systems. It can reveal the effects of interspecific relationships on the yield of intercropping systems, providing the theoretical and guiding basis for optimizing intercropping agriculture. To this end, a pot experiment was set up to investigate the effects of root interaction and planting density on grain yield, interspecific competition and complementarity of barley-pea intercropping system. In the experiment, two kinds of species interactions were set, only aboveground interaction (whole root partition of two intercropped crops) and aboveground and belowground interaction (without root partition between two intercropped crops), in combination with two planting densities of barley (15 plantspot-1 and 20 plantspot-1). The study was designed to provide the theoretical basis for raising yield management technique under intercropping based on interspecific relationship optimization. The study showed that: 1) compared with the corresponding monoculture system, average dry matter accumulation of intercropping systems increased by 3.6%–11.3%. The contribution rate of belowground interaction was 53.9%–63.5%. For the intercropping system with belowground and aboveground interactions, increased planting density of barley enhanced dry matter accumulation of the system by 12.5%–14.4%. But, for the intercropping system only with aboveground interaction, it increased by 3.3%–6.7%. Similarly, barley-pea intercropping total grain yield was 8.6%–33.8% higher than the average grain yield of the corresponding monocultures. The contribution rate of the existing belowground interaction was 2.4%–16.2%. With increasing planting density of barley, the intercropping system existing both belowground and aboveground interactions increased total grain yield by 7.0%–10.9%; while the intercropping system existing only aboveground interaction only increased by 1.2%–2.6%. This suggested that belowground interaction was critical for close planting in intercropping systems. 2) Compared with corresponding monoculture treatments, intercropping increased harvest indexes (i.e., HI) of barley and pea by 8.7%–21.0% and 3.3%–31.7%, respectively. The harvest index of intercropped barley increased with increasing planting density of barley while that of intercropped pea decreased. The trend of the decline was more obvious under whole root partition. 3) Belowground interaction without root partition increased land equivalent ratio (LER), but high planting density of barley decreased LER in barley-pea intercropping system. This suggested that belowground root interaction was the main force behind the advantages of intercropping. 4) The belowground interaction significantly increased the competitiveness (by up to 40.1%–89.1%) of barley to pea during the period of co-growth. The average competitiveness increased by 11.0%–49.9% with increasing barley planting density. 5) A quadratic relationship existed between total grain yield of barley-pea intercropping system and the average competitiveness of barley to pea during the whole period of co-growth. High grain yields of both crops were obtained when competitiveness was 0.13–0.33. Our results showed that appropriately improving the competitiveness of barley and pea intercropping system (especially at barley grain-filling stage) by increasing the planting density of barley (25 plantpot-1) increased total grain yield of the intercropping system.
Interspecific relationship is an important biological basis for high-yield and efficient utilization of resources in intercropping systems. It can reveal the effects of interspecific relationships on the yield of intercropping systems, providing the theoretical and guiding basis for optimizing intercropping agriculture. To this end, a pot experiment was set up to investigate the effects of root interaction and planting density on grain yield, interspecific competition and complementarity of barley-pea intercropping system. In the experiment, two kinds of species interactions were set, only aboveground interaction (whole root partition of two intercropped crops) and aboveground and belowground interaction (without root partition between two intercropped crops), in combination with two planting densities of barley (15 plantspot-1 and 20 plantspot-1). The study was designed to provide the theoretical basis for raising yield management technique under intercropping based on interspecific relationship optimization. The study showed that: 1) compared with the corresponding monoculture system, average dry matter accumulation of intercropping systems increased by 3.6%–11.3%. The contribution rate of belowground interaction was 53.9%–63.5%. For the intercropping system with belowground and aboveground interactions, increased planting density of barley enhanced dry matter accumulation of the system by 12.5%–14.4%. But, for the intercropping system only with aboveground interaction, it increased by 3.3%–6.7%. Similarly, barley-pea intercropping total grain yield was 8.6%–33.8% higher than the average grain yield of the corresponding monocultures. The contribution rate of the existing belowground interaction was 2.4%–16.2%. With increasing planting density of barley, the intercropping system existing both belowground and aboveground interactions increased total grain yield by 7.0%–10.9%; while the intercropping system existing only aboveground interaction only increased by 1.2%–2.6%. This suggested that belowground interaction was critical for close planting in intercropping systems. 2) Compared with corresponding monoculture treatments, intercropping increased harvest indexes (i.e., HI) of barley and pea by 8.7%–21.0% and 3.3%–31.7%, respectively. The harvest index of intercropped barley increased with increasing planting density of barley while that of intercropped pea decreased. The trend of the decline was more obvious under whole root partition. 3) Belowground interaction without root partition increased land equivalent ratio (LER), but high planting density of barley decreased LER in barley-pea intercropping system. This suggested that belowground root interaction was the main force behind the advantages of intercropping. 4) The belowground interaction significantly increased the competitiveness (by up to 40.1%–89.1%) of barley to pea during the period of co-growth. The average competitiveness increased by 11.0%–49.9% with increasing barley planting density. 5) A quadratic relationship existed between total grain yield of barley-pea intercropping system and the average competitiveness of barley to pea during the whole period of co-growth. High grain yields of both crops were obtained when competitiveness was 0.13–0.33. Our results showed that appropriately improving the competitiveness of barley and pea intercropping system (especially at barley grain-filling stage) by increasing the planting density of barley (25 plantpot-1) increased total grain yield of the intercropping system.
2016, 24(3): 274-283.
Abstract:
With globe climate changing, the intensifying uncertainty of precipitation induced inconsistency of irrigation schedule in different years and at different growth stages of crops. Therefore, conventional irrigation schedule fails to guide irrigation activities precisely. It becomes increasingly important for irrigation management and sustainable development of agriculture to explore changes of agricultural irrigation requirement against the background of frequently extreme meteorology events. In this paper, meteorological data of the recent 63 years (from 1951 to 2013) and soil data in Xinxiang City of northern Henan, as well as crop growth parameters were used to establish the model of drought irrigation index according to the relationships among precipitation, irrigation, evapotranspiration (ETC) and available soil water. In the model, drought irrigation index (DII) was [1, 1]. Once DII was less than 0, irrigation was necessary. On the basis of winter wheat-summer maize planting schedule in the study area, the model was used to calculate multi-year DIIs for the recent 63 years. Consequently, annual irrigation times potentially meeting the agricultural requirement were obtained based on DIIs from 1951 to 2013. Three representative growing seasons of winter wheat and summer maize were selected as wet (19851986 for winter wheat, 2003 for summer maize), normal (20042005 for winter wheat, 1993 for summer maize) and dry (19831984 for winter wheat, 2009 for summer maize) growing seasons. Water requirement of two crops in different growing seasons were calculated, and DIIs in there representative growing seasons of winter wheat and summer maize were calculated too under the conditions with and without irrigation. The results showed that required annual irrigation times ranged from 2 to 7 with an average of 5.1 in recently 63 years in norther Henan Province. ETC of winter wheat and summer maize in wet, normal, dry growing seasons were 489.4 mm, 551.4 mm, 481.7 mm and 466.1 mm, 477.8 mm, 529.3 mm, respectively. Under the condition without irrigation, the winter wheat and summer maize suffered varying degrees of drought in typical growing seasons. Winter wheat respectively needed 2, 3, and 4 times irrigation, while summer maize respectively needed 1, 2 and 3 times irrigation in wet, normal and dry actual representative growing seasons. Even if in wet growth seasons of summer maize, irrigation also required during periods with high ETC but no timely rainfall. DII could guide irrigation well according to the relationship among meteorology, available soil water and crop growth information. It was practicable to decide irrigation time with DII. With climate changing from 2003 to 2013, the frequency of irrigation times fluctuated more remarkable, and interannual drought stress took place more frequently than the past 63 years. Scientific and reasonable irrigation managements should be worked out in order to reduce the influence of drought stress on crop growth.
With globe climate changing, the intensifying uncertainty of precipitation induced inconsistency of irrigation schedule in different years and at different growth stages of crops. Therefore, conventional irrigation schedule fails to guide irrigation activities precisely. It becomes increasingly important for irrigation management and sustainable development of agriculture to explore changes of agricultural irrigation requirement against the background of frequently extreme meteorology events. In this paper, meteorological data of the recent 63 years (from 1951 to 2013) and soil data in Xinxiang City of northern Henan, as well as crop growth parameters were used to establish the model of drought irrigation index according to the relationships among precipitation, irrigation, evapotranspiration (ETC) and available soil water. In the model, drought irrigation index (DII) was [1, 1]. Once DII was less than 0, irrigation was necessary. On the basis of winter wheat-summer maize planting schedule in the study area, the model was used to calculate multi-year DIIs for the recent 63 years. Consequently, annual irrigation times potentially meeting the agricultural requirement were obtained based on DIIs from 1951 to 2013. Three representative growing seasons of winter wheat and summer maize were selected as wet (19851986 for winter wheat, 2003 for summer maize), normal (20042005 for winter wheat, 1993 for summer maize) and dry (19831984 for winter wheat, 2009 for summer maize) growing seasons. Water requirement of two crops in different growing seasons were calculated, and DIIs in there representative growing seasons of winter wheat and summer maize were calculated too under the conditions with and without irrigation. The results showed that required annual irrigation times ranged from 2 to 7 with an average of 5.1 in recently 63 years in norther Henan Province. ETC of winter wheat and summer maize in wet, normal, dry growing seasons were 489.4 mm, 551.4 mm, 481.7 mm and 466.1 mm, 477.8 mm, 529.3 mm, respectively. Under the condition without irrigation, the winter wheat and summer maize suffered varying degrees of drought in typical growing seasons. Winter wheat respectively needed 2, 3, and 4 times irrigation, while summer maize respectively needed 1, 2 and 3 times irrigation in wet, normal and dry actual representative growing seasons. Even if in wet growth seasons of summer maize, irrigation also required during periods with high ETC but no timely rainfall. DII could guide irrigation well according to the relationship among meteorology, available soil water and crop growth information. It was practicable to decide irrigation time with DII. With climate changing from 2003 to 2013, the frequency of irrigation times fluctuated more remarkable, and interannual drought stress took place more frequently than the past 63 years. Scientific and reasonable irrigation managements should be worked out in order to reduce the influence of drought stress on crop growth.
JIN Baihui,
YANG Lingyu,
XU Yulong,
ZHANG Yijie,
WEI Zhengmeng,
KANG Hongkuan,
HOU Yongming,
ZHU Shusheng,
ZHU Youyong,
HE Xiahong
2016, 24(3): 284-292.
Abstract:
Continuous cropping obstacle is a key limit factor of Panax notoginseng cultivation. The reason for continuous cropping obstacles, such as changes of soil microorganisms have not been clearly, especially under natural conditions. To evaluate the impact of P. notoginseng planting on soil microbial communities and continuous cropping obstacle mechanisms, the soil nutrients and soil microorganism community structure were investigated in different fields after different years of P. notoginseng harvested in three towns (Ganhe, A’meng and Panlong) in Wenshan City, Yunnan Province. In each town, 7 fields were selected as soil sampling sites. Seven fields were planted other corps rather than P. notoginseng, six of which were at 1 to 6 years after P. notoginseng harvested, the other one which never planted P. notoginseng was set as the control (CK). Biolog-ECO method was used to analyse the average well color development (AWCD) and diversity of microbial community to explore microbial community dynamics. The results showed that AWCD of soil microorganisms was not regularly changed with increasing years after P. notoginseng harvested. After cultivated for 96 hours, activity of soil microorganisms reached the highest level. Cluster analysis of utilization of 6 groups (31 kinds) of carbon resources showed that in three towns, carbon resources utilization of soils at 1 and 6 years after P. notoginseng harvested were classed in one group, indicting the same characteristics of carbon resources utilization. No obvious regularity was observed for other years. The use of carbohydrates, polymeric substances, carboxylic acid and phenols by soil microorganisms in 1 and 6 years after P. notoginseng harvested were 25.97%55.59% and 53.14%65.68% more than those of CK. Soil nitrogen, phosphorus, potassium and organic matter contents increased at 2 years, decreased at 4 and 5 years after P. notoginseng harvested. Soil nitrogen, phosphorus, potassium and organic matter contents in three towns, as well as Shannon-Wiener index, evenness index and Simposon’s index of soil microorganisms in A’meng and Panlong Towns at 1 to 6 years after P. notoginseng harvested were not significantly different compared with that of CK. The results suggested that rotation with other crops at least for 6 years was indispensable to avoid continuous cropping obstacles of P. notoginseng.
Continuous cropping obstacle is a key limit factor of Panax notoginseng cultivation. The reason for continuous cropping obstacles, such as changes of soil microorganisms have not been clearly, especially under natural conditions. To evaluate the impact of P. notoginseng planting on soil microbial communities and continuous cropping obstacle mechanisms, the soil nutrients and soil microorganism community structure were investigated in different fields after different years of P. notoginseng harvested in three towns (Ganhe, A’meng and Panlong) in Wenshan City, Yunnan Province. In each town, 7 fields were selected as soil sampling sites. Seven fields were planted other corps rather than P. notoginseng, six of which were at 1 to 6 years after P. notoginseng harvested, the other one which never planted P. notoginseng was set as the control (CK). Biolog-ECO method was used to analyse the average well color development (AWCD) and diversity of microbial community to explore microbial community dynamics. The results showed that AWCD of soil microorganisms was not regularly changed with increasing years after P. notoginseng harvested. After cultivated for 96 hours, activity of soil microorganisms reached the highest level. Cluster analysis of utilization of 6 groups (31 kinds) of carbon resources showed that in three towns, carbon resources utilization of soils at 1 and 6 years after P. notoginseng harvested were classed in one group, indicting the same characteristics of carbon resources utilization. No obvious regularity was observed for other years. The use of carbohydrates, polymeric substances, carboxylic acid and phenols by soil microorganisms in 1 and 6 years after P. notoginseng harvested were 25.97%55.59% and 53.14%65.68% more than those of CK. Soil nitrogen, phosphorus, potassium and organic matter contents increased at 2 years, decreased at 4 and 5 years after P. notoginseng harvested. Soil nitrogen, phosphorus, potassium and organic matter contents in three towns, as well as Shannon-Wiener index, evenness index and Simposon’s index of soil microorganisms in A’meng and Panlong Towns at 1 to 6 years after P. notoginseng harvested were not significantly different compared with that of CK. The results suggested that rotation with other crops at least for 6 years was indispensable to avoid continuous cropping obstacles of P. notoginseng.
2016, 24(3): 293-305.
Abstract:
Using crop and soil data from agro-meteorological observational stations together with meteorological data from meteorological stations, the study evaluated the adaptability of APSIM-Wheat (Agricultural Production Systems sIMulator- Wheat) model in winter wheat planting zones in Southwest China (SWC). Then, the model was used to calculate the potential and rainfed yields of winter wheat from 1961 to 2010 in SWC. The relative contribution rates of the changes in main climatic factors during crop growing season to the changes in simulated potential and rainfed yields of winter wheat were determined with the stepwise regression method. The study results showed that APSIM-Wheat model performed well in simulating phenology, above-ground biomass and yield of five representative winter wheat varieties in SWC. Root Mean Square Error (RMSE) between simulated and observed wheat phenology were less than 7.0 d for all the varieties. Normalized Root Mean Square Error (NRMSE) between simulated and observed above-ground biomass and yield were lower than 25% and 21%, respectively, for all the varieties. Total solar radiation during wheat growing season decreased significantly at 36% of the study stations centered in the northern, southeastern and mid-southern SWC. The effective accumulative temperature of not less than 0 ℃ during wheat growing season increased significantly at 68% of the study stations centered in the western SWC, while average diurnal temperature range during wheat growing season decreased significantly at 30% of study stations centered in the mid-southern SWC (P < 0.05). Total precipitation during wheat growing season decreased at most of study stations centered in the southern and southeastern SWC from 1961 to 2010. As a result, simulated potential yield of winter wheat also showed a significant decline at 65% of study stations, especially in the mid-southern and northern SWC. Simulated yield of rainfed wheat showed a significant decline at 25% of study stations, especially in the northern SWC. The contribution rates of the decrease of solar radiation and diurnal temperature range, the increase of temperature during wheat growing season were 45%, 2% and 36%, respectively, to the reduction in simulated potential yield, and 36%, 39% and 8%, respectively, to the reduction in simulated yield of rainfed wheat. The contribution rate of decreasing precipitation during wheat growing season was 7% to the reduction in simulated yield of rainfed wheat. In general, solar radiation and temperature had the most obvious effects on simulated yield variations of winter wheat in SWC from 1961 to 2010. The decrease in solar radiation and precipitation, and the increase in temperature during winter wheat growing season led to a decline in both simulated potential and rainfed yields at most of study stations in SWC, while the decreased diurnal temperature range had both negative and positive effects on potential and rainfed yields, respectively. Quantifying the impacts of light, temperature and precipitation on wheat production using APSIM model provided a sound foundation for taking countermeasures for adapting to climate change and improving wheat yield in Southwest China.
Using crop and soil data from agro-meteorological observational stations together with meteorological data from meteorological stations, the study evaluated the adaptability of APSIM-Wheat (Agricultural Production Systems sIMulator- Wheat) model in winter wheat planting zones in Southwest China (SWC). Then, the model was used to calculate the potential and rainfed yields of winter wheat from 1961 to 2010 in SWC. The relative contribution rates of the changes in main climatic factors during crop growing season to the changes in simulated potential and rainfed yields of winter wheat were determined with the stepwise regression method. The study results showed that APSIM-Wheat model performed well in simulating phenology, above-ground biomass and yield of five representative winter wheat varieties in SWC. Root Mean Square Error (RMSE) between simulated and observed wheat phenology were less than 7.0 d for all the varieties. Normalized Root Mean Square Error (NRMSE) between simulated and observed above-ground biomass and yield were lower than 25% and 21%, respectively, for all the varieties. Total solar radiation during wheat growing season decreased significantly at 36% of the study stations centered in the northern, southeastern and mid-southern SWC. The effective accumulative temperature of not less than 0 ℃ during wheat growing season increased significantly at 68% of the study stations centered in the western SWC, while average diurnal temperature range during wheat growing season decreased significantly at 30% of study stations centered in the mid-southern SWC (P < 0.05). Total precipitation during wheat growing season decreased at most of study stations centered in the southern and southeastern SWC from 1961 to 2010. As a result, simulated potential yield of winter wheat also showed a significant decline at 65% of study stations, especially in the mid-southern and northern SWC. Simulated yield of rainfed wheat showed a significant decline at 25% of study stations, especially in the northern SWC. The contribution rates of the decrease of solar radiation and diurnal temperature range, the increase of temperature during wheat growing season were 45%, 2% and 36%, respectively, to the reduction in simulated potential yield, and 36%, 39% and 8%, respectively, to the reduction in simulated yield of rainfed wheat. The contribution rate of decreasing precipitation during wheat growing season was 7% to the reduction in simulated yield of rainfed wheat. In general, solar radiation and temperature had the most obvious effects on simulated yield variations of winter wheat in SWC from 1961 to 2010. The decrease in solar radiation and precipitation, and the increase in temperature during winter wheat growing season led to a decline in both simulated potential and rainfed yields at most of study stations in SWC, while the decreased diurnal temperature range had both negative and positive effects on potential and rainfed yields, respectively. Quantifying the impacts of light, temperature and precipitation on wheat production using APSIM model provided a sound foundation for taking countermeasures for adapting to climate change and improving wheat yield in Southwest China.
2016, 24(3): 306-315.
Abstract:
Under global climate warming and drying, temperatures have increased to varying degrees around the world. Global warming has caused significant changes in agro-ecological environments, of which maize yield and quality have been found to be heavily influenced by meteorological factors. Therefore the analysis of the suitability degree to climate change of maize during growth period could provide an important guide for increasing agricultural production. Basis on a climatic suitability degree model for optimal maize production, daily meteorological data for 19562010 from eight meteorological stations in four cities in West Liaoning Province were analyzed. The analysis included the spatial and temporal distribution characteristics of climate suitability degree during the whole growth period and each individual growth stage of maize using spatial interpolation, Empirical Orthogonal Function (EOF) analysis and wavelet transformation analysis. The results showed that: 1) The suitability degrees of precipitation, sunshine and integrated climate followed a declining trend during the maize growth period from 1956 to 2010. The suitability degree of integrated climate dropped at sowing, emergence and maturity stages but rose at flowering stage. 2) The suitability degrees of both temperature and sunshine during the whole growth period of maize and the suitability degree of integrated climate during sowing and maturity stages tracked an increasing trend from south to north, from west to east, from west to southeast and northeast, and from northeast to southwest in West Liaoning Province. However, the suitability degrees of temperature and sunshine at emergence stage were in contrast to that of sowing, with a general declining trend from northwest to southeast and northeast. The suitability degrees of precipitation, integrated climate during the whole growth period of maize and integrated climate during flowering followed a “low-high-low-high” zonal distribution from north to south. The constraint factors during sowing, emergence and flowering were precipitation, sunshine and sunshine. 3) EOF analysis showed that the percentage anomaly of suitability degree of integrated climate during the whole growth period of maize in West Liaoning Province generally slightly declined in space from southwest to northeast. Wavelet transformation analysis suggested the time coefficient of first feature vectors of integrated climate suitability degree at 3 scales of oscillation period ― 1430 years, 814 years and 37 years.
Under global climate warming and drying, temperatures have increased to varying degrees around the world. Global warming has caused significant changes in agro-ecological environments, of which maize yield and quality have been found to be heavily influenced by meteorological factors. Therefore the analysis of the suitability degree to climate change of maize during growth period could provide an important guide for increasing agricultural production. Basis on a climatic suitability degree model for optimal maize production, daily meteorological data for 19562010 from eight meteorological stations in four cities in West Liaoning Province were analyzed. The analysis included the spatial and temporal distribution characteristics of climate suitability degree during the whole growth period and each individual growth stage of maize using spatial interpolation, Empirical Orthogonal Function (EOF) analysis and wavelet transformation analysis. The results showed that: 1) The suitability degrees of precipitation, sunshine and integrated climate followed a declining trend during the maize growth period from 1956 to 2010. The suitability degree of integrated climate dropped at sowing, emergence and maturity stages but rose at flowering stage. 2) The suitability degrees of both temperature and sunshine during the whole growth period of maize and the suitability degree of integrated climate during sowing and maturity stages tracked an increasing trend from south to north, from west to east, from west to southeast and northeast, and from northeast to southwest in West Liaoning Province. However, the suitability degrees of temperature and sunshine at emergence stage were in contrast to that of sowing, with a general declining trend from northwest to southeast and northeast. The suitability degrees of precipitation, integrated climate during the whole growth period of maize and integrated climate during flowering followed a “low-high-low-high” zonal distribution from north to south. The constraint factors during sowing, emergence and flowering were precipitation, sunshine and sunshine. 3) EOF analysis showed that the percentage anomaly of suitability degree of integrated climate during the whole growth period of maize in West Liaoning Province generally slightly declined in space from southwest to northeast. Wavelet transformation analysis suggested the time coefficient of first feature vectors of integrated climate suitability degree at 3 scales of oscillation period ― 1430 years, 814 years and 37 years.
2016, 24(3): 316-324.
Abstract:
Soil erosion is one of the most serious ecological problems in the world, and the terrain is an important factor influencing the soil erosion. Some scholars applied the relevant ideas and theories of landscape ecology and the algorithm of partial factors in Universal Soil Loss Equation (USLE), and brought forward the soil loss evaluation index (SLsw index) for soil erosion measurement at different scales. The SLsw index can reflect to a certain extent the process of soil loss and erosion, avoid the common problems of physical model, and provide us research ideas and methods in the study of land use and soil loss and erosion on different scales. But it was too simple to study the topography, so this study was to modify the topographic factor (G) in SLsw, and then obtained soil erosion evaluation index with correction factor G (SLsw_G). This study chose the Loess Hilly Gully Region of Ansai watershed as the research area, and used GIS technology to calculate the SLsw_G based on the data of Ansai catchment DEM data, daily rainfall data of hydrological observation station, soil sampling data and land use data. The measured sediment transport volume in Ansai watershed was used to verify the modified index. And then the soil erosion intensity and its temporal and spatial variation characteristics of Ansai watershed were analyzed. The results showed that the soil erosion distribution was basically the same before and after the amendment of SL index. The soil erosion was higher in southeast region of Ansai watershed, while it was lower in the northwest region. Due to the influence of human factors, soil conservation measures were relatively weak in the southeastern part of the Ansai watershed. Meanwhile, there were more light soil clay and silt, and the clay and silt had obvious bond when they were wet, so it was easy to be washed away in the course of raining. According to the data of soil sampling analysis, the content of soil clay and silt were higher in the southeast, so it was easy to cause the soil erosion in the southeastern part of the Ansai watershed. According to the T test, the SLsw and SLsw_G has the variance homogeneity before and after the amendment, and P=0.037<0.05. Compared with the measured sediment transport volume, the correlation between the modified index and the measured volume was greater than the correlation between the original index and the measured volume. It can be concluded that the modified index can better explain the regional soil erosion of the study area.
Soil erosion is one of the most serious ecological problems in the world, and the terrain is an important factor influencing the soil erosion. Some scholars applied the relevant ideas and theories of landscape ecology and the algorithm of partial factors in Universal Soil Loss Equation (USLE), and brought forward the soil loss evaluation index (SLsw index) for soil erosion measurement at different scales. The SLsw index can reflect to a certain extent the process of soil loss and erosion, avoid the common problems of physical model, and provide us research ideas and methods in the study of land use and soil loss and erosion on different scales. But it was too simple to study the topography, so this study was to modify the topographic factor (G) in SLsw, and then obtained soil erosion evaluation index with correction factor G (SLsw_G). This study chose the Loess Hilly Gully Region of Ansai watershed as the research area, and used GIS technology to calculate the SLsw_G based on the data of Ansai catchment DEM data, daily rainfall data of hydrological observation station, soil sampling data and land use data. The measured sediment transport volume in Ansai watershed was used to verify the modified index. And then the soil erosion intensity and its temporal and spatial variation characteristics of Ansai watershed were analyzed. The results showed that the soil erosion distribution was basically the same before and after the amendment of SL index. The soil erosion was higher in southeast region of Ansai watershed, while it was lower in the northwest region. Due to the influence of human factors, soil conservation measures were relatively weak in the southeastern part of the Ansai watershed. Meanwhile, there were more light soil clay and silt, and the clay and silt had obvious bond when they were wet, so it was easy to be washed away in the course of raining. According to the data of soil sampling analysis, the content of soil clay and silt were higher in the southeast, so it was easy to cause the soil erosion in the southeastern part of the Ansai watershed. According to the T test, the SLsw and SLsw_G has the variance homogeneity before and after the amendment, and P=0.037<0.05. Compared with the measured sediment transport volume, the correlation between the modified index and the measured volume was greater than the correlation between the original index and the measured volume. It can be concluded that the modified index can better explain the regional soil erosion of the study area.
2016, 24(3): 325-334.
Abstract:
Cultivated lands are among the most fundamental resources for the existence and development of mankind. Scientific analysis of the spatial distribution patterns and evolutionary characteristics of cultivated lands is highly useful in the protection and resource optimization of cultivated lands. Working on such research project, this paper extracted cultivated land data from the 2005, 2009 and 2013 land use data of the Longquanyi District of Chengdu, China, and calculated the kernel density, concentration index of cultivated land and conducted spatial autocorrelation analysis by using GIS platform. The results suggested that: 1) the evolution of cultivated lands in 2005–2013 in the study area was driven by aggregation. Spatially, cultivated land densities in the northwestern and northern regions were higher than those in the southern and central regions. Regions with higher cultivated land density apparently expanded from northwest to southwest, while regions with lower cultivated land density sporadically expanded from urban to rural area. 2) For distribution of cultivated lands, feature land density in the north was generally higher than that in the south. The distribution of cultivated lands was relatively concentrated, with more concentrated years in terms of the time series, but with more significant variation in the spatial differentiations among the regions. 3) There was a significant spatial autocorrelation for global distribution, with strengthening heterogeneity for local distribution of cultivated lands in the study area. Spatial units with higher proportion of cultivated lands was concentrated in the northern and northwestern regions and reduced westwards from year to year. The units with lower proportions of cultivated lands were more distributed at built-up areas and suburbs surrounding the urban centers, with two stages of expansion and contraction. Because of urban expansion and rural land consolidation in 2005–2013, there were hot spots and cold spots in different localities of the distributed cultivated lands. This study provided the theoretical methods and references for determining the dynamic evolution of regional cultivated lands and developing relevant policies for protection and resource optimization of cultivated lands.
Cultivated lands are among the most fundamental resources for the existence and development of mankind. Scientific analysis of the spatial distribution patterns and evolutionary characteristics of cultivated lands is highly useful in the protection and resource optimization of cultivated lands. Working on such research project, this paper extracted cultivated land data from the 2005, 2009 and 2013 land use data of the Longquanyi District of Chengdu, China, and calculated the kernel density, concentration index of cultivated land and conducted spatial autocorrelation analysis by using GIS platform. The results suggested that: 1) the evolution of cultivated lands in 2005–2013 in the study area was driven by aggregation. Spatially, cultivated land densities in the northwestern and northern regions were higher than those in the southern and central regions. Regions with higher cultivated land density apparently expanded from northwest to southwest, while regions with lower cultivated land density sporadically expanded from urban to rural area. 2) For distribution of cultivated lands, feature land density in the north was generally higher than that in the south. The distribution of cultivated lands was relatively concentrated, with more concentrated years in terms of the time series, but with more significant variation in the spatial differentiations among the regions. 3) There was a significant spatial autocorrelation for global distribution, with strengthening heterogeneity for local distribution of cultivated lands in the study area. Spatial units with higher proportion of cultivated lands was concentrated in the northern and northwestern regions and reduced westwards from year to year. The units with lower proportions of cultivated lands were more distributed at built-up areas and suburbs surrounding the urban centers, with two stages of expansion and contraction. Because of urban expansion and rural land consolidation in 2005–2013, there were hot spots and cold spots in different localities of the distributed cultivated lands. This study provided the theoretical methods and references for determining the dynamic evolution of regional cultivated lands and developing relevant policies for protection and resource optimization of cultivated lands.
2016, 24(3): 335-344.
Abstract:
Farmland transfer, supported by both the national and local governments, has largely promoted the transformation of agricultural management and modernization. Specifically, the increasing scope and scale of farmland transfer dramatically changed the industrial structure and input-output of agriculture. Thus farmland transfer has a significant effect on the agro-ecosystem. To assess eco-environmental effects of the transformation of the mode of agricultural management due to farmland transfer, this study analyzed three aspects of farmland transfer ― production efficiency, environmental impact and overall sustainability of agro-ecosystems. This was done in a case study of Rongchang County in Chongqing, China. To do that, the input-output of ordinary farmers and agricultural contractors, which respectively represented the agricultural management patterns before and after farmland transfer, was analyzed. The emergy evaluation method used proved to be effective in analyzing the efficiency and sustainability of ecosystems. Emergy evaluation method overcame the weakness of traditional methods of energy analysis as it integrated different forms of energy into a common physical basis known as solar emergy. This method took multiple important factors into consideration (e.g., natural resources, labor and ecosystem services), generally neglected in other similar methods. The results showed that the input for purchasing resources decreased by 70.48% while emergy output increased by 2.15% after farmland transfer. Thus emergy yield ratio (EYR) changed from 0.01 before farmland transfer to 0.04 after that, which represented an increase of 300.00%. This increase was mainly due to agricultural machinery input rather than labor force input, which lowered the overall input and increased the efficiency of production. For a single input item, when its’ renewability factor was less than that of the ecosystem, decreasing input reduced the environmental loading ratio (ELR); for the item, whose renewability factor was higher than that of the ecosystem and vice versa. The decline in labor force together with the increase in pesticide and fertilizer use increased the environmental load of an ecosystem. Thus ELR changed from 0.12 to 0.65, which was a rise of 441.67% after farmland transfer. Emergy sustainability index (ESI) changed from 0.08 to 0.06, a decline of 25.00%. This indicated that the moderate increase in farmland for a household significantly reduced the cost of agricultural production and increased the market competitiveness of agricultural products. However, in modern agriculture, the drive for increased output and added values of agricultural products had substantially increased the use of pesticides and fertilizers. This has in turn intensified the potential risks of agro-ecosystems. In summary, an intensive agricultural development mode should be carefully selected and adopted in order to achieve the goals of sustainable agro-ecosystems. Therefore national policies should pay more attention to the selection of agricultural modes during the process of farmland transfer and scaling farmland cultivation.
Farmland transfer, supported by both the national and local governments, has largely promoted the transformation of agricultural management and modernization. Specifically, the increasing scope and scale of farmland transfer dramatically changed the industrial structure and input-output of agriculture. Thus farmland transfer has a significant effect on the agro-ecosystem. To assess eco-environmental effects of the transformation of the mode of agricultural management due to farmland transfer, this study analyzed three aspects of farmland transfer ― production efficiency, environmental impact and overall sustainability of agro-ecosystems. This was done in a case study of Rongchang County in Chongqing, China. To do that, the input-output of ordinary farmers and agricultural contractors, which respectively represented the agricultural management patterns before and after farmland transfer, was analyzed. The emergy evaluation method used proved to be effective in analyzing the efficiency and sustainability of ecosystems. Emergy evaluation method overcame the weakness of traditional methods of energy analysis as it integrated different forms of energy into a common physical basis known as solar emergy. This method took multiple important factors into consideration (e.g., natural resources, labor and ecosystem services), generally neglected in other similar methods. The results showed that the input for purchasing resources decreased by 70.48% while emergy output increased by 2.15% after farmland transfer. Thus emergy yield ratio (EYR) changed from 0.01 before farmland transfer to 0.04 after that, which represented an increase of 300.00%. This increase was mainly due to agricultural machinery input rather than labor force input, which lowered the overall input and increased the efficiency of production. For a single input item, when its’ renewability factor was less than that of the ecosystem, decreasing input reduced the environmental loading ratio (ELR); for the item, whose renewability factor was higher than that of the ecosystem and vice versa. The decline in labor force together with the increase in pesticide and fertilizer use increased the environmental load of an ecosystem. Thus ELR changed from 0.12 to 0.65, which was a rise of 441.67% after farmland transfer. Emergy sustainability index (ESI) changed from 0.08 to 0.06, a decline of 25.00%. This indicated that the moderate increase in farmland for a household significantly reduced the cost of agricultural production and increased the market competitiveness of agricultural products. However, in modern agriculture, the drive for increased output and added values of agricultural products had substantially increased the use of pesticides and fertilizers. This has in turn intensified the potential risks of agro-ecosystems. In summary, an intensive agricultural development mode should be carefully selected and adopted in order to achieve the goals of sustainable agro-ecosystems. Therefore national policies should pay more attention to the selection of agricultural modes during the process of farmland transfer and scaling farmland cultivation.
2016, 24(3): 345-355.
Abstract:
Due to the serious secondary soil salinization, salt injury has become a limiting factor of the development of high quality alfalfa industry in Northwest and North China. Brassinosteroid (BR) has been globally recognized as a new plant growth hormone with high and broad spectrum activity, which could regulate plant growth and development and mitigate a series of abiotic stresses due to high salinity, heavy metal contamination, high temperatures, low temperatures, drought and hypoxia. It also plays an important role in regulating the photosynthesis and absorption of trace element of plants. Given the importance of the study of the effects of BR on trace element absorption and fluorescence kinetics parameters in Medicago sativa L. seedlings under salt stress, we investigated salt resistance and possible physiological regulation mechanism of M. sativa seedlings induced by exogenous 2,4-Epibrassinolide (EBR). The effects of EBR on the absorption, transportation and allocation of trace elements, leaf PSⅡ function, electron transport rate and light allocation in seedlings of M. sativa cv. Zhongmu No.3 and M. sativa cv. Longzhong under NaCl stress were determined using the hydroponics method. Four treatments were conducted in the experiment ― CK (distilled water), 150 mmol·L-1 NaCl, 0.1 μmol·L-1 EBR and 150 mmol·L-1 NaCl + 0.1 μmol·L-1 EBR. The results showed that Cu2+ content increased significantly in different organs (leave, stem and root) of the seedlings, also Fe2+, Mn2+ and Zn2+ contents significantly decreased and then Fe2+/Na+, Mn2+/Na+, Cu2+/Na+ and Zn2+/Na+ declined markedly under 150 mmol·L-1 NaCl stress. The metabolic process of the uptake, transportation and distribution of inorganic ions was disordered and PSⅡ reaction center damaged. Concurrently, there was a drop in the transportation ratio of photosynthetic electrons (ETR) and photochemical reaction energy. NaCl stress facilitated antenna dissipated energy and reaction center dissipated energy, which resulted in a drop in photosynthetic capacity. This condition was reversed by the addition of 0.1 μmol·L-1 EBR under NaCl stress. Addition of EBR significantly decreased Cu2+ content in different plant organs (leave, stem and root), while significantly increased contents of Fe2+, Mn2+ and Zn2+, and ratios of Fe2+/Na+, Mn2+/Na+, Cu2+/Na+ and Zn2+/Na+. The uptake and transportation of inorganic ions were effectively regulated, accompanied by a decrease in antagonism among positive ions like Na+, Fe2+, Mn2+, Cu2+, Zn2+, etc. Leaf F0 and NPQ significantly decreased and Fm, Fv/F0, Fv/Fm, ФPSⅡ, Fv′/Fm′, qP and ETR significantly increased. Absorbed light energy was allocated more to photochemical reaction energy, less light was allocated to antenna pigment dissipation and excess light energy to reaction center. This illustrated that EBR improved the selective absorption, transportation and distribution of inorganic ions and maintained ion metabolic balance under NaCl stress. Furthermore, EBR effectively alleviated any harm to M. sativa seedlings caused by NaCl stress by raising ETR, reducing antenna heat dissipation and excess light energy of reaction center and maintaining a higher level PSⅡ photochemistry activity. This further stimulated even energy allocation between PSⅠ and PSⅡ and decreased damage to PSⅡ reaction center.
Due to the serious secondary soil salinization, salt injury has become a limiting factor of the development of high quality alfalfa industry in Northwest and North China. Brassinosteroid (BR) has been globally recognized as a new plant growth hormone with high and broad spectrum activity, which could regulate plant growth and development and mitigate a series of abiotic stresses due to high salinity, heavy metal contamination, high temperatures, low temperatures, drought and hypoxia. It also plays an important role in regulating the photosynthesis and absorption of trace element of plants. Given the importance of the study of the effects of BR on trace element absorption and fluorescence kinetics parameters in Medicago sativa L. seedlings under salt stress, we investigated salt resistance and possible physiological regulation mechanism of M. sativa seedlings induced by exogenous 2,4-Epibrassinolide (EBR). The effects of EBR on the absorption, transportation and allocation of trace elements, leaf PSⅡ function, electron transport rate and light allocation in seedlings of M. sativa cv. Zhongmu No.3 and M. sativa cv. Longzhong under NaCl stress were determined using the hydroponics method. Four treatments were conducted in the experiment ― CK (distilled water), 150 mmol·L-1 NaCl, 0.1 μmol·L-1 EBR and 150 mmol·L-1 NaCl + 0.1 μmol·L-1 EBR. The results showed that Cu2+ content increased significantly in different organs (leave, stem and root) of the seedlings, also Fe2+, Mn2+ and Zn2+ contents significantly decreased and then Fe2+/Na+, Mn2+/Na+, Cu2+/Na+ and Zn2+/Na+ declined markedly under 150 mmol·L-1 NaCl stress. The metabolic process of the uptake, transportation and distribution of inorganic ions was disordered and PSⅡ reaction center damaged. Concurrently, there was a drop in the transportation ratio of photosynthetic electrons (ETR) and photochemical reaction energy. NaCl stress facilitated antenna dissipated energy and reaction center dissipated energy, which resulted in a drop in photosynthetic capacity. This condition was reversed by the addition of 0.1 μmol·L-1 EBR under NaCl stress. Addition of EBR significantly decreased Cu2+ content in different plant organs (leave, stem and root), while significantly increased contents of Fe2+, Mn2+ and Zn2+, and ratios of Fe2+/Na+, Mn2+/Na+, Cu2+/Na+ and Zn2+/Na+. The uptake and transportation of inorganic ions were effectively regulated, accompanied by a decrease in antagonism among positive ions like Na+, Fe2+, Mn2+, Cu2+, Zn2+, etc. Leaf F0 and NPQ significantly decreased and Fm, Fv/F0, Fv/Fm, ФPSⅡ, Fv′/Fm′, qP and ETR significantly increased. Absorbed light energy was allocated more to photochemical reaction energy, less light was allocated to antenna pigment dissipation and excess light energy to reaction center. This illustrated that EBR improved the selective absorption, transportation and distribution of inorganic ions and maintained ion metabolic balance under NaCl stress. Furthermore, EBR effectively alleviated any harm to M. sativa seedlings caused by NaCl stress by raising ETR, reducing antenna heat dissipation and excess light energy of reaction center and maintaining a higher level PSⅡ photochemistry activity. This further stimulated even energy allocation between PSⅠ and PSⅡ and decreased damage to PSⅡ reaction center.
LUO Yinghong,
ZHANG Yiyang,
LIU Xiaoying,
LI Shuang,
LIU Kun,
CUI Chaogang,
TAN Guanping,
ZHOU Jiheng
2016, 24(3): 356-364.
Abstract:
Nicotine is not only an important chemical component of tobacco leaves, but also one of the important quality indexes of cigarette. The current state of flue-cured tobacco in China with nicotine on the high end has severely influenced China-produced tobacco leaf quality. Effectively reducing nicotine content of tobacco leaves and improving flue-cured tobacco usability has been a difficult issue in the tobacco production industry. The content of nicotine in tobacco doubled and redoubled after topping. Because of the sharp rise in nicotine content after tobacco topping and cells oxidative burst due to mechanical damage, testing started with a series of physiological changes induced by?topping in this study. The two methods used in the test included daub of both ascorbic acid and glutathione (AsA+GSH), and daub of ascorbic acid (AsA). Other three methods were also applied in the experiment, duab of buffer solvent after topping, conventional topping and not topping. These methods were applied to tobacco wounds after topping to suppress the rise in active oxygen content, explore the relationship between active oxygen content and jasmonic acid-stimulating nicotine content growth, and to compare the effects of the two methods on suppressing the rise in active oxygen and nicotine content. The results showed that the rise in the contents of super oxygen anion, hydrogen peroxide and malondialdehyde of tobacco leaves dropped when daubing AsA+GSH and AsA to the topping wounds. Hydrogen peroxide degradation was slower than that of oxygen anion, which accumulated in tobacco. Jasmonic acid content under daub of AsA+GSH or AsA treatments was lower than that under conventional topping treatment at 6 h after treatment and with adverse effect on jasmonic acid. At 96 h after treatment, nicotine content of leaves under AsA+GSH treatment was 21.5% lower than that under conventional topping treatment. The content of nicotine in tobacco leaves under AsA treatment was 17.5% lower than that under conventional topping treatment. Correlation analysis among response intensity of each detection index to topping showed significant or extremely significant correlation between the detection indexes. Also at 24 h after topping, active oxygen content of each treatment dropped back to the non-topped level (not topping treatment). The test showed that daubing antioxidant substances (AsA+GSH) to tobacco wounds after topping effectively suppressed reactive oxygen species, jasmonic acid and nicotine contents rise. There was also a close relationship between reactive oxygen species, jasmonic acid and nicotine. AsA+GSH treatment was better than AsA treatment in antioxidant activity, and was therefore better in suppressing nicotine content rise in tobacco leaves after topping.
Nicotine is not only an important chemical component of tobacco leaves, but also one of the important quality indexes of cigarette. The current state of flue-cured tobacco in China with nicotine on the high end has severely influenced China-produced tobacco leaf quality. Effectively reducing nicotine content of tobacco leaves and improving flue-cured tobacco usability has been a difficult issue in the tobacco production industry. The content of nicotine in tobacco doubled and redoubled after topping. Because of the sharp rise in nicotine content after tobacco topping and cells oxidative burst due to mechanical damage, testing started with a series of physiological changes induced by?topping in this study. The two methods used in the test included daub of both ascorbic acid and glutathione (AsA+GSH), and daub of ascorbic acid (AsA). Other three methods were also applied in the experiment, duab of buffer solvent after topping, conventional topping and not topping. These methods were applied to tobacco wounds after topping to suppress the rise in active oxygen content, explore the relationship between active oxygen content and jasmonic acid-stimulating nicotine content growth, and to compare the effects of the two methods on suppressing the rise in active oxygen and nicotine content. The results showed that the rise in the contents of super oxygen anion, hydrogen peroxide and malondialdehyde of tobacco leaves dropped when daubing AsA+GSH and AsA to the topping wounds. Hydrogen peroxide degradation was slower than that of oxygen anion, which accumulated in tobacco. Jasmonic acid content under daub of AsA+GSH or AsA treatments was lower than that under conventional topping treatment at 6 h after treatment and with adverse effect on jasmonic acid. At 96 h after treatment, nicotine content of leaves under AsA+GSH treatment was 21.5% lower than that under conventional topping treatment. The content of nicotine in tobacco leaves under AsA treatment was 17.5% lower than that under conventional topping treatment. Correlation analysis among response intensity of each detection index to topping showed significant or extremely significant correlation between the detection indexes. Also at 24 h after topping, active oxygen content of each treatment dropped back to the non-topped level (not topping treatment). The test showed that daubing antioxidant substances (AsA+GSH) to tobacco wounds after topping effectively suppressed reactive oxygen species, jasmonic acid and nicotine contents rise. There was also a close relationship between reactive oxygen species, jasmonic acid and nicotine. AsA+GSH treatment was better than AsA treatment in antioxidant activity, and was therefore better in suppressing nicotine content rise in tobacco leaves after topping.
2016, 24(3): 365-372.
Abstract:
Cultivated soils contamination by heavy metals have become increasingly contentious to decision makers, farmers, consumers and health professionals around the globe. Phytoremediation is a key strategy for decontaminating cultivated soils polluted by heavy metals. Hyperaccumulator plants are limited by their soil occupation rather than agricultural production in China. Intercropping system of hyperaccumulator plants and crops have been recommended for both of remediation and production in the same time. The accumulation of heavy metal in plants is due to root growth and root exudates. However, plant root morphology and exudates vary, which is a key issue in intercropping systems. In order to investigate the effects of lead (Pb) stress on the exudates of organic acids by hyperaccumulator plant and crop roots in intercropping and monocropping systems, a hydroponic aeration experiment was conducted in a greenhouse. A crop (maize) or hyperaccumulator (Arabisalpina L. var. parviflora Franch) monocropping and intercropping systems were set up as the control and treatment plots, respectively. The effects of 400 mgL-1 Pb stress on root morphology, organic acids (oxalic acid, tartaric acid, citric acid, malic acid, lactic acid and acetic acid) exudation and lead accumulation in the intercropping and monocropping systems were determined. The results showed that compared with monocropped maize, lactic acid was obtained from intercropped maize root exudates. The numbers of split root, root surface area and root density of intercropped maize increased by 60%, 15% and 42%, respectively. Root and shoot biomass under intercropped maize increased by 108% and 75%, respectively, whereas root Pb content of intercropped maize decreased by 44%. Compared with monocropped A. alpina, acetic acid and lactic acid determined from root exudates of intercropped A. alpine, showing 103%1 700% increase in root exudates amount. Also Pb accumulation in underground and aboveground plant parts of intercropped A. alpina increased respectively by 49% and 75% with 22% increase in transfer coefficient of Pb. Furthermore, for monocropped A. alpine, Pb content in shoots was only significantly positively correlated with oxalic acid content; but for intercropped A. alpine, it was significantly positive correlated with contents of oxalic acid, oxalic acid and malic acid both in shoot and root of A. alpine. The results suggested that root exudation of organic acids was critical in changing Pb accumulation characteristics in maize and A. alpina intercropping system. The number and components of organic acids in root exudates changed under intercropping system, which affected Pb content and accumulation characteristics of A. alpine and maize. Pb content increased in A. alpine and decreased in maize. In short, hyperaccumulator A. alpine and maize were recommended for remediation of cultivated soil contaminated with Pb.
Cultivated soils contamination by heavy metals have become increasingly contentious to decision makers, farmers, consumers and health professionals around the globe. Phytoremediation is a key strategy for decontaminating cultivated soils polluted by heavy metals. Hyperaccumulator plants are limited by their soil occupation rather than agricultural production in China. Intercropping system of hyperaccumulator plants and crops have been recommended for both of remediation and production in the same time. The accumulation of heavy metal in plants is due to root growth and root exudates. However, plant root morphology and exudates vary, which is a key issue in intercropping systems. In order to investigate the effects of lead (Pb) stress on the exudates of organic acids by hyperaccumulator plant and crop roots in intercropping and monocropping systems, a hydroponic aeration experiment was conducted in a greenhouse. A crop (maize) or hyperaccumulator (Arabisalpina L. var. parviflora Franch) monocropping and intercropping systems were set up as the control and treatment plots, respectively. The effects of 400 mgL-1 Pb stress on root morphology, organic acids (oxalic acid, tartaric acid, citric acid, malic acid, lactic acid and acetic acid) exudation and lead accumulation in the intercropping and monocropping systems were determined. The results showed that compared with monocropped maize, lactic acid was obtained from intercropped maize root exudates. The numbers of split root, root surface area and root density of intercropped maize increased by 60%, 15% and 42%, respectively. Root and shoot biomass under intercropped maize increased by 108% and 75%, respectively, whereas root Pb content of intercropped maize decreased by 44%. Compared with monocropped A. alpina, acetic acid and lactic acid determined from root exudates of intercropped A. alpine, showing 103%1 700% increase in root exudates amount. Also Pb accumulation in underground and aboveground plant parts of intercropped A. alpina increased respectively by 49% and 75% with 22% increase in transfer coefficient of Pb. Furthermore, for monocropped A. alpine, Pb content in shoots was only significantly positively correlated with oxalic acid content; but for intercropped A. alpine, it was significantly positive correlated with contents of oxalic acid, oxalic acid and malic acid both in shoot and root of A. alpine. The results suggested that root exudation of organic acids was critical in changing Pb accumulation characteristics in maize and A. alpina intercropping system. The number and components of organic acids in root exudates changed under intercropping system, which affected Pb content and accumulation characteristics of A. alpine and maize. Pb content increased in A. alpine and decreased in maize. In short, hyperaccumulator A. alpine and maize were recommended for remediation of cultivated soil contaminated with Pb.
2016, 24(3): 373-383.
Abstract:
Sixty-three surface (0-20 cm) soil samples were collected in two typical Benggang areas (BG1 and BG2) in Huangnikeng Benggang Group and an adjacent hillside without Benggang (CK) in Changting County of southwestern Fujian Province. The contents of seven heavy metals in those samples were measured, and each heavy metal’s source was identified by means of correlation and principal component analyses. Finally, the potential ecological risks of heavy metals were assessed on the basis of soil background values of Fujian Province and the second class standard of national soil environmental quality. The results indicated that the order of contents of heavy metals in the investigated soil was Zn (105.56 mg·kg-1) > Pb (67.21 mg·kg-1) > As (61.47 mg·kg-1) > Cu (22.33 mg·kg-1) > Cr (17.12 mg·kg-1) > Ni (5.24 mg·kg-1) > Cd (0.80 mg·kg-1), the contents of Pb and Cd in both BG1 and BG2 were higher than those in CK, while those of Cu, Zn, Ni, Cr, As and Cd were opposite. The contents of Zn, Pb, As and Cd in BG1 were 1.12, 2.82, 8.68 and 13.33 times, BG2 were 1.11, 1.36, 11.22 and 16.67 times, and CK were 1.58, 1.60, 5.14 and 14.44 times the averages of soil background values in Fujian Province. Compared with the second class standard of national soil environmental quality (GB15618—1995), the contents of As in Benggangs and CK soils were 1.92 and 2.70 times, respectively, and the content of Cd was 2.31 and 2.60 times, respectively, the nation standard. From upper slope to bottom of slope in Benggang systems, the contents of Pb, Zn and Cd increased, Cu and Cr basically remained stable, while Ni decreased. From top to bottom of CK slope, Cu, Zn, Ni, Cr and Cd contents increased, and Pb content decreased slightly. As content in study region kept relatively consistent. According to heavy metals resources analysis with correlation and principal component analyses methods, Cu, Ni and Cr mainly came from parent materials, Zn was associated with livestock breeding probably, Cd and As originated from substrate weathering and mining of rare earth elements, and Pb were ascribed to compound pollution of bedrock mineralization, coal combustion, and exhaust emission on provincial highway (No. 205). The potential ecological risk coefficients of Cd and As were classified as ‘extreme strong level’ and ‘strong level’ respectively, and those of Cu, Zn, Ni, Pb, Cr were ranked as ‘slight level’ with soil background values in Fujian Province as reference; while only Cd was ranked as ‘strong level’ and others were in range of ‘slight level’, when the second class standard of national soil environmental quality was used as reference. The order of potential ecological risk index was BG2>CK>BG1. The proper measures would be suggested to control the severe contamination of Cd and As in this area.
Sixty-three surface (0-20 cm) soil samples were collected in two typical Benggang areas (BG1 and BG2) in Huangnikeng Benggang Group and an adjacent hillside without Benggang (CK) in Changting County of southwestern Fujian Province. The contents of seven heavy metals in those samples were measured, and each heavy metal’s source was identified by means of correlation and principal component analyses. Finally, the potential ecological risks of heavy metals were assessed on the basis of soil background values of Fujian Province and the second class standard of national soil environmental quality. The results indicated that the order of contents of heavy metals in the investigated soil was Zn (105.56 mg·kg-1) > Pb (67.21 mg·kg-1) > As (61.47 mg·kg-1) > Cu (22.33 mg·kg-1) > Cr (17.12 mg·kg-1) > Ni (5.24 mg·kg-1) > Cd (0.80 mg·kg-1), the contents of Pb and Cd in both BG1 and BG2 were higher than those in CK, while those of Cu, Zn, Ni, Cr, As and Cd were opposite. The contents of Zn, Pb, As and Cd in BG1 were 1.12, 2.82, 8.68 and 13.33 times, BG2 were 1.11, 1.36, 11.22 and 16.67 times, and CK were 1.58, 1.60, 5.14 and 14.44 times the averages of soil background values in Fujian Province. Compared with the second class standard of national soil environmental quality (GB15618—1995), the contents of As in Benggangs and CK soils were 1.92 and 2.70 times, respectively, and the content of Cd was 2.31 and 2.60 times, respectively, the nation standard. From upper slope to bottom of slope in Benggang systems, the contents of Pb, Zn and Cd increased, Cu and Cr basically remained stable, while Ni decreased. From top to bottom of CK slope, Cu, Zn, Ni, Cr and Cd contents increased, and Pb content decreased slightly. As content in study region kept relatively consistent. According to heavy metals resources analysis with correlation and principal component analyses methods, Cu, Ni and Cr mainly came from parent materials, Zn was associated with livestock breeding probably, Cd and As originated from substrate weathering and mining of rare earth elements, and Pb were ascribed to compound pollution of bedrock mineralization, coal combustion, and exhaust emission on provincial highway (No. 205). The potential ecological risk coefficients of Cd and As were classified as ‘extreme strong level’ and ‘strong level’ respectively, and those of Cu, Zn, Ni, Pb, Cr were ranked as ‘slight level’ with soil background values in Fujian Province as reference; while only Cd was ranked as ‘strong level’ and others were in range of ‘slight level’, when the second class standard of national soil environmental quality was used as reference. The order of potential ecological risk index was BG2>CK>BG1. The proper measures would be suggested to control the severe contamination of Cd and As in this area.
2016, 24(3): 384-391.
Abstract:
As the rapid development of the economy and agriculture, the water quality of many rivers and lakes is degrading due to agricultural non-point source pollution. The low polluted wastewater (LPW) is an eutrophic water body containing N, P and many microelements, meeting the Pollutant Discharge Standard of Municipal Wastewater Treatment Plant (Class one, B level). LPW can be reused before draining into downstream water system. Rural LPW mainly comes from agricultural production and farmer’s livelihood, including sewage tail water, farmland runoff and polluted river water. In this paper, the effect of C︰N ratio of LPW on the removal of nitrogen (N), phosphorus (P) and chemical oxygen demand (COD) of LPW was studied with floating-bed Oenanthe javanica system as the research subject to provide reference for increasing purification efficiency of floating-bed plant system. In the experiment, domestic sewage with or without glucose addition of floating-bed Oenanthe javanica system were two treatments (TWW-HC and TWW treatments), and no plant floating-bed system was used as the control treatment. The experiment lasted for 82 days with once water exchange in median time of the process. The results showed that N and P removal performance were better in TWW-HC treatment than that in TWW. External carbon addition rapidly reduced N and P contents, and the removal rates of total nitrogen (TN), ammonia nitrogen (NH+4-N) and total phosphorus (TP) were 40.8%, 38.4%, and 62.8%, respectively, under TWW-HC treatment after 3 days of treatment. The removal rate of TN of TWW-HC was 73.9%96.0% during the whole experiment, which was higher than that of TWW (with the removal rate of 60.6%85.9%). The removal rate of total phosphorus (TP) was 68.0%81.1% in TWW-HC, which was higher than that in TWW and control treatments (with the removal rates of 21.3%54.9% for TWW and 19.2%58.1% for control, respectively). The biomass, average plant height, and relative growth rate of O. javanica were significantly higher in TWW-HC than in TWW. Plant uptake of TWW-HC accounted for 58.2% of the removed N amounts and 37.6% of the removed P amounts, greatly higher than those of TWW (8.7% of the removal N amounts and 11.0% of the removal P amounts). More than 80% of the removed N amounts were eliminated by other pathways in TWW treatment, but the percentage was only 37.3% in TWW-HC. Sedimentation contributed for 16.0% of the removed N amounts in control treatment, but only 8.5% in TWW and 4.6% in TWW-HC, respectively. Similar tendency was found in TP removal pathways. These results showed that the floating-bed O. javanica system evidently reduced N and P amounts in sediments compared to control. Results also indicated that increasing C︰N ratio to an appropriate range of LPW was beneficial for growth and nutrient uptake of O. javanica, which also contributed to N and P removal efficiently.
As the rapid development of the economy and agriculture, the water quality of many rivers and lakes is degrading due to agricultural non-point source pollution. The low polluted wastewater (LPW) is an eutrophic water body containing N, P and many microelements, meeting the Pollutant Discharge Standard of Municipal Wastewater Treatment Plant (Class one, B level). LPW can be reused before draining into downstream water system. Rural LPW mainly comes from agricultural production and farmer’s livelihood, including sewage tail water, farmland runoff and polluted river water. In this paper, the effect of C︰N ratio of LPW on the removal of nitrogen (N), phosphorus (P) and chemical oxygen demand (COD) of LPW was studied with floating-bed Oenanthe javanica system as the research subject to provide reference for increasing purification efficiency of floating-bed plant system. In the experiment, domestic sewage with or without glucose addition of floating-bed Oenanthe javanica system were two treatments (TWW-HC and TWW treatments), and no plant floating-bed system was used as the control treatment. The experiment lasted for 82 days with once water exchange in median time of the process. The results showed that N and P removal performance were better in TWW-HC treatment than that in TWW. External carbon addition rapidly reduced N and P contents, and the removal rates of total nitrogen (TN), ammonia nitrogen (NH+4-N) and total phosphorus (TP) were 40.8%, 38.4%, and 62.8%, respectively, under TWW-HC treatment after 3 days of treatment. The removal rate of TN of TWW-HC was 73.9%96.0% during the whole experiment, which was higher than that of TWW (with the removal rate of 60.6%85.9%). The removal rate of total phosphorus (TP) was 68.0%81.1% in TWW-HC, which was higher than that in TWW and control treatments (with the removal rates of 21.3%54.9% for TWW and 19.2%58.1% for control, respectively). The biomass, average plant height, and relative growth rate of O. javanica were significantly higher in TWW-HC than in TWW. Plant uptake of TWW-HC accounted for 58.2% of the removed N amounts and 37.6% of the removed P amounts, greatly higher than those of TWW (8.7% of the removal N amounts and 11.0% of the removal P amounts). More than 80% of the removed N amounts were eliminated by other pathways in TWW treatment, but the percentage was only 37.3% in TWW-HC. Sedimentation contributed for 16.0% of the removed N amounts in control treatment, but only 8.5% in TWW and 4.6% in TWW-HC, respectively. Similar tendency was found in TP removal pathways. These results showed that the floating-bed O. javanica system evidently reduced N and P amounts in sediments compared to control. Results also indicated that increasing C︰N ratio to an appropriate range of LPW was beneficial for growth and nutrient uptake of O. javanica, which also contributed to N and P removal efficiently.
2016, 24(3): 392-402.
Abstract:
Forest resource is the largest carbon pool in terrestrial ecosystem, which contributes carbon to the global carbon cycle incomparably. The forest ecosystem in northern Hebei Province plays an important role in soil and water conservation, and carbon sink increase. In this study we took broadleaved forest, coniferous forest, mixed forest, economic forest and shrub in northern Hebei Province as objects to research the amount of carbon sequestration in this area by using Carbon Budget Model of the Canadian Forest Sector (CBM-CFS3) which referenced by IPCC as a platform. The data was based on original data of the 7th national forest continuous inventory and forest vegetation survey data of the area. Firstly, the literature-volume growth curve equations were created by comparing several growth functions based on the 7th national forest continuous inventory of continuous sample survey data for each forest type, as the driving force for model to simulate forest carbon storage. Secondly, volume-biomass transition equations, conversion parameters and forest biomass components (stem, bark, branch, foliage) proportion parameters of different forest types were estimated using the power function model, and further plotted by collecting a large number literature data in each forest types. And then, forest vegetation carbon storage, carbon density and carbon sequestration rate of different forest types in northern Hebei Province were calculated after the model running, debugging and simulating. The results showed that the fitting coefficients of different forest vegetation growth curve equations were exceeded 0.7. The parameters of fitting coefficient correlations of all volume-biomass transfer equations were exceeded 0.8, and there were significant differences among most proportion equations for biomass components (stem, bark, branch, foliage). By the comparison with estimated results by using measured data, the results of forest vegetation carbon storage, average carbon density and carbon sequestration rate simulated by using CBM-CFS3 were more reasonable. It could provide the basis to evaluate forest vegetation carbon sequestration potential in this area. The total forest vegetation carbon storage and average carbon density in northern Hebei Province in 2010 were 59.66 Tg(C) and 25.05 Mg(C)·hm-2, respectively. The forest vegetation carbon sequestration rate ranged from 0.07 Mg(C)hm-2a-1 to 1.87 Mg(C)hm-2a-1. The carbon storages and average carbon densities of broadleaved forest, coniferous forest, mixed forest, economic forest in northern Hebei Province were 30.97 Tg(C), 12.36 Tg(C), 15.73 Tg(C), 0.60 Tg(C) and 26.09 Mg(C)·hm-2, 26.14 Mg(C)·hm-2, 24.50 Mg(C)·hm-2, 7.53 Mg(C)·hm-2, respectively. The spatial distribution of forest vegetation carbon density and carbon sequestration rate in northern Hebei Province showed an increase trend from northwest to southeast. After the forestation and afforestation, the area of forest increased by 6 400 km2, and forest vegetation carbon storage increased 19.54 Tg(C) (not include shrub) in the study area. The potential ability of forest vegetation carbon sequestration in this area will increased quickly in future, because of its young-middle age forest structure. Therefore, afforestation played an important role in increasing forest vegetation carbon storage and carbon sequestration rate.
Forest resource is the largest carbon pool in terrestrial ecosystem, which contributes carbon to the global carbon cycle incomparably. The forest ecosystem in northern Hebei Province plays an important role in soil and water conservation, and carbon sink increase. In this study we took broadleaved forest, coniferous forest, mixed forest, economic forest and shrub in northern Hebei Province as objects to research the amount of carbon sequestration in this area by using Carbon Budget Model of the Canadian Forest Sector (CBM-CFS3) which referenced by IPCC as a platform. The data was based on original data of the 7th national forest continuous inventory and forest vegetation survey data of the area. Firstly, the literature-volume growth curve equations were created by comparing several growth functions based on the 7th national forest continuous inventory of continuous sample survey data for each forest type, as the driving force for model to simulate forest carbon storage. Secondly, volume-biomass transition equations, conversion parameters and forest biomass components (stem, bark, branch, foliage) proportion parameters of different forest types were estimated using the power function model, and further plotted by collecting a large number literature data in each forest types. And then, forest vegetation carbon storage, carbon density and carbon sequestration rate of different forest types in northern Hebei Province were calculated after the model running, debugging and simulating. The results showed that the fitting coefficients of different forest vegetation growth curve equations were exceeded 0.7. The parameters of fitting coefficient correlations of all volume-biomass transfer equations were exceeded 0.8, and there were significant differences among most proportion equations for biomass components (stem, bark, branch, foliage). By the comparison with estimated results by using measured data, the results of forest vegetation carbon storage, average carbon density and carbon sequestration rate simulated by using CBM-CFS3 were more reasonable. It could provide the basis to evaluate forest vegetation carbon sequestration potential in this area. The total forest vegetation carbon storage and average carbon density in northern Hebei Province in 2010 were 59.66 Tg(C) and 25.05 Mg(C)·hm-2, respectively. The forest vegetation carbon sequestration rate ranged from 0.07 Mg(C)hm-2a-1 to 1.87 Mg(C)hm-2a-1. The carbon storages and average carbon densities of broadleaved forest, coniferous forest, mixed forest, economic forest in northern Hebei Province were 30.97 Tg(C), 12.36 Tg(C), 15.73 Tg(C), 0.60 Tg(C) and 26.09 Mg(C)·hm-2, 26.14 Mg(C)·hm-2, 24.50 Mg(C)·hm-2, 7.53 Mg(C)·hm-2, respectively. The spatial distribution of forest vegetation carbon density and carbon sequestration rate in northern Hebei Province showed an increase trend from northwest to southeast. After the forestation and afforestation, the area of forest increased by 6 400 km2, and forest vegetation carbon storage increased 19.54 Tg(C) (not include shrub) in the study area. The potential ability of forest vegetation carbon sequestration in this area will increased quickly in future, because of its young-middle age forest structure. Therefore, afforestation played an important role in increasing forest vegetation carbon storage and carbon sequestration rate.
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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