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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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2015 Vol. 23, No. 4
Display Method:
2015, 23(4): 383-391.
doi: 10.13930/j.cnki.cjea.141331
Abstract:
Drought is the most important limitation to maize yield. Studies have shown that drought can affect plant morphology, dry matter accumulation, physiological processes and reproductive organ development, thereby decreasing grain weight and per-ear kernel. With a specific focus on the development of male and female organs, this paper reviewed the effects of drought on the development of reproductive organs and anthesis-silking interval. Drought before anthesis delayed tassel and ear development, decreased total spikelets and increased kernel abortion, thereby lowering per-ear grain number. Drought during tasseling and silking hindered tasseling, delayed silking and prolonged anthesis-silking interval. In addition, severe drought during tasseling induced ultra-structural changes in pollens and silk, which severely affected pollination and fertilization and eventually resulted in bald- heading and grain number reduction. Moreover, drought during filling stage triggered leaf senescence, low photosynthetate accumulation, limited grain filling, induced grain weight lowering and eventually yield reduction. In terms of source-sink relationship, drought before grain-filling reduced grain number in response to weak sink, eventually reducing yield. Drought during grain-filling stunted the development of vegetative organs such as leaf senescence, which hindered the accumulation and transport of assimilates. Thus, source restricted yield increase.
Drought is the most important limitation to maize yield. Studies have shown that drought can affect plant morphology, dry matter accumulation, physiological processes and reproductive organ development, thereby decreasing grain weight and per-ear kernel. With a specific focus on the development of male and female organs, this paper reviewed the effects of drought on the development of reproductive organs and anthesis-silking interval. Drought before anthesis delayed tassel and ear development, decreased total spikelets and increased kernel abortion, thereby lowering per-ear grain number. Drought during tasseling and silking hindered tasseling, delayed silking and prolonged anthesis-silking interval. In addition, severe drought during tasseling induced ultra-structural changes in pollens and silk, which severely affected pollination and fertilization and eventually resulted in bald- heading and grain number reduction. Moreover, drought during filling stage triggered leaf senescence, low photosynthetate accumulation, limited grain filling, induced grain weight lowering and eventually yield reduction. In terms of source-sink relationship, drought before grain-filling reduced grain number in response to weak sink, eventually reducing yield. Drought during grain-filling stunted the development of vegetative organs such as leaf senescence, which hindered the accumulation and transport of assimilates. Thus, source restricted yield increase.
2015, 23(4): 392-401.
doi: 10.13930/j.cnki.cjea.150246
Abstract:
This article reviewed the current situations of ratoon rice in China and summarized the research progresses on the ratoon rice yield formation from the perspectives of the developmental genetics and physiological ecology. The key cultivation technology and eco-physiological mechanisms of the ratooning plants from low and high rice stubbles were comprehensively reviewed also. The ratoon rice technique gives two yields from one seeding, with significant yield advantages over single cropping rice and double cropping rice. Appropriate rice cultivars and cultivation methods are decisive factors of high yield of ratoon rice. For the ratoon rice from the high stubble of the hand-harvested first-season rice, to get high yield, the hybrid indica rice cultivars with heavy panicles were the best choices, which were relative weak in tillering ability for the first-season, and high regeneration capacity from lower nodes for the ratoon season. For the ratoon rice from the lower stubble of the mechanically harvested first-season rice, to get high yield, the hybrid indica rice with high regeneration capacity from lower nodes, or hybrid indica and japonica/indica rice crosses with the heavy panicle but weak photosensitivity were the best choices. Previous studies also suggested that roots adjustment was crucial to realize yield potential of ratoon rice. The ratoon rice root system was composed of the roots of the first-season rice and new roots of the ratoon season rice. The higher root activity from the mature stage of the first-season rice to the heading stage of the ratoon rice improved germination of axillary bud in rice stubbles and increased the panicles number of ratoon rice, which was favorable for high yield of ratoon rice. According to our study results and previous reports, we summarize the high-yielding cultural techniques of ratoon rice from hand-harvested first-season rice, such as early sowing in optimal time, ridge transplanting and furrow irrigation, two-time soil drying (heavy drought at tillering stage and moderate drought at 25 days after full heading stage in the first season), increased N application for bud development, and higher stubbles of 40 50 cm. In addition, the key cultivation technology and eco-physiological mechanisms of the ratoon rice from the low stubbles of machine-harvested first-season rice were comprehensively discussed from variety selection, fertilizer application, and the height of the remained stubbles. At last, the problems and future trends of ratoon rice were discussed. It was suggested that ratoon rice from low stubbles of mechanically harvested rice were the direction of ratoon rice development. The corresponding researches were therefore prospected.
This article reviewed the current situations of ratoon rice in China and summarized the research progresses on the ratoon rice yield formation from the perspectives of the developmental genetics and physiological ecology. The key cultivation technology and eco-physiological mechanisms of the ratooning plants from low and high rice stubbles were comprehensively reviewed also. The ratoon rice technique gives two yields from one seeding, with significant yield advantages over single cropping rice and double cropping rice. Appropriate rice cultivars and cultivation methods are decisive factors of high yield of ratoon rice. For the ratoon rice from the high stubble of the hand-harvested first-season rice, to get high yield, the hybrid indica rice cultivars with heavy panicles were the best choices, which were relative weak in tillering ability for the first-season, and high regeneration capacity from lower nodes for the ratoon season. For the ratoon rice from the lower stubble of the mechanically harvested first-season rice, to get high yield, the hybrid indica rice with high regeneration capacity from lower nodes, or hybrid indica and japonica/indica rice crosses with the heavy panicle but weak photosensitivity were the best choices. Previous studies also suggested that roots adjustment was crucial to realize yield potential of ratoon rice. The ratoon rice root system was composed of the roots of the first-season rice and new roots of the ratoon season rice. The higher root activity from the mature stage of the first-season rice to the heading stage of the ratoon rice improved germination of axillary bud in rice stubbles and increased the panicles number of ratoon rice, which was favorable for high yield of ratoon rice. According to our study results and previous reports, we summarize the high-yielding cultural techniques of ratoon rice from hand-harvested first-season rice, such as early sowing in optimal time, ridge transplanting and furrow irrigation, two-time soil drying (heavy drought at tillering stage and moderate drought at 25 days after full heading stage in the first season), increased N application for bud development, and higher stubbles of 40 50 cm. In addition, the key cultivation technology and eco-physiological mechanisms of the ratoon rice from the low stubbles of machine-harvested first-season rice were comprehensively discussed from variety selection, fertilizer application, and the height of the remained stubbles. At last, the problems and future trends of ratoon rice were discussed. It was suggested that ratoon rice from low stubbles of mechanically harvested rice were the direction of ratoon rice development. The corresponding researches were therefore prospected.
2015, 23(4): 402-415.
doi: 10.13930/j.cnki.cjea.141218
Abstract:
Although crop yield estimation is a necessary requirement of modern agriculture, it is one of the most difficult things to monitor in agriculture. Timely and accurate simulation of crop yield is important for national agricultural decision-making, agricultural production management, grain storage safety, etc. Model simulations of crop growth and yield formation are currently the most commonly method of crop yield estimation. Crop growth and yield formation models were divided into four categories after comparison on theoretical basis, which were empirical linear models, crop growth models, light use efficiency (LUE) models and coupled models. As so many different crop growth models existed, further classification of the models was necessary. The empirical linear models was further divided into four sub-groups according to their estimation methods, while the crop growth models were further divided into four sub-groups on the basis of the main or special driving factors. Then the paper analyzed the merits and demerits of each group of models. Although empirical linear models were simple and needed less data, they had poor generalization in space and time. Crop growth models were more comprehensive and reasonable as they were capable of simulating almost all plant physiological processes and even human disturbances. The shortages of these models were also obvious. The models required more parameters, most of which were not easily accessible. The models also had high software, hardware and professional (knowledge) requirements to accomplish operations. LUE models were capable of comprehensive simulation of light use and easily fitted for remote sensing data to improve simulation precision. The most obvious demerit of LUE models was their inability to simulate human disturbances, a non-ignorable factor, as farm environment in modern agriculture was highly subjected to human activity. Although the coupled models combined the merits of both crop and LUE models, they also shared the demerits of these models and with the theoretical basis widely questioned. This study also discussed and drew conclusions on the use of remote sensing data into the models. After concluded on the limiting factors of development of the models, hot spots of research on the models were discussed. The study finally summarized some possible development trends and prospects of the crop yield estimation models. It was concluded that the models had the potential to be more stable, efficient, accurate, practical and cost efficient as they were drivable on common software and hardware conditions and that even farmers could use them. The possible ways of resolving crop yield-estimation difficulties were optimizing crop models and innovatively using new remote sensing data such as radar data, hyperspectral data and high spatial resolution data.
Although crop yield estimation is a necessary requirement of modern agriculture, it is one of the most difficult things to monitor in agriculture. Timely and accurate simulation of crop yield is important for national agricultural decision-making, agricultural production management, grain storage safety, etc. Model simulations of crop growth and yield formation are currently the most commonly method of crop yield estimation. Crop growth and yield formation models were divided into four categories after comparison on theoretical basis, which were empirical linear models, crop growth models, light use efficiency (LUE) models and coupled models. As so many different crop growth models existed, further classification of the models was necessary. The empirical linear models was further divided into four sub-groups according to their estimation methods, while the crop growth models were further divided into four sub-groups on the basis of the main or special driving factors. Then the paper analyzed the merits and demerits of each group of models. Although empirical linear models were simple and needed less data, they had poor generalization in space and time. Crop growth models were more comprehensive and reasonable as they were capable of simulating almost all plant physiological processes and even human disturbances. The shortages of these models were also obvious. The models required more parameters, most of which were not easily accessible. The models also had high software, hardware and professional (knowledge) requirements to accomplish operations. LUE models were capable of comprehensive simulation of light use and easily fitted for remote sensing data to improve simulation precision. The most obvious demerit of LUE models was their inability to simulate human disturbances, a non-ignorable factor, as farm environment in modern agriculture was highly subjected to human activity. Although the coupled models combined the merits of both crop and LUE models, they also shared the demerits of these models and with the theoretical basis widely questioned. This study also discussed and drew conclusions on the use of remote sensing data into the models. After concluded on the limiting factors of development of the models, hot spots of research on the models were discussed. The study finally summarized some possible development trends and prospects of the crop yield estimation models. It was concluded that the models had the potential to be more stable, efficient, accurate, practical and cost efficient as they were drivable on common software and hardware conditions and that even farmers could use them. The possible ways of resolving crop yield-estimation difficulties were optimizing crop models and innovatively using new remote sensing data such as radar data, hyperspectral data and high spatial resolution data.
2015, 23(4): 416-424.
doi: 10.13930/j.cnki.cjea.141261
Abstract:
Soil surface mulching with plastic film or crop straws can prevent secondary soil salinization and improve crop water use efficiency (WUE). An experiment was conducted in a moderately saline field to investigate the effects of different mulching methods on soil characteristics and sunflower yield. Seven treatments were conducted in the study, including 9 000 kg·hm-2 chopped maize straw mulching (F0.9), 6 000 kg·hm-2 chopped maize straw mulching (F0.6), whole maize straw mulching (YZ), whole sunflower straw mulching (KZ), plastic film mulching (DM), second-used plastic film mulching (MG) and no mulching (CK). The study analyzed the effects of different mulching methods on soil water and salt movement, sunflower yield and economic benefits of moderately saline soils. The aim of the study was to improve production effects of surface mulching of saline soils. The results showed that salt contents in the 0 5 cm soil layer under treatments of F0.9, YZ and DM decreased while those under MG, F0.6, KZ and CK treatments increased at harvest compared with thoes at sowing. Also salt contents at the 0 20 cm soil layer under F0.9 and DM treatments decreased while those under F0.6, YZ, MG, KZ and CK treatments increased at harvest compared with those at sowing. Different mulching treatments had significantly different effects on soil salt content in the 0 20 cm soil layer. The effects of different mulching methods on soil salt content were inclined to similar with increasing soil depth. In terms of salt content in the 0 20 cm soil layer, F0.9 treatment was the lowest, which suggested that F0.9 treatment had the best salt inhibitory effect. The inhibitory effects on soil salt of mulching measures of DM and F0.6 were similar. For different straw mulching treatments, the inhibitory effects on soil salt of F0.9 and F0.6 were better than those of YZ and KZ. For different plastic film mulching treatments, the inhibitory effect on soil salt of DM was better than that of MG. In the 0 5 cm and 0 20 cm soil layers, average soil water content under DM treatment was higher than those under straw mulching treatments throughout the entire growth period of sunflower. Average soil water content under chopped straw mulching treatments (F0.9 and F0.6) were higher than that under whole straw mulching treatments (YZ and KZ) throughout the growth period. Compared with CK, DM and F0.9 improved 0 100 cm soil water storage significantly. Treatments F0.9 and DM decreased soil water variation coefficients in the 0 100 cm soil layer and thereby maintained stable soil water content throughout the growth season. The order of sunflower yield for different treatments was DM > F0.9 > YZ > F0.6 > MG > KZ > CK. The different mulching methods enhanced crop WUE by improving farmland environment. WUE under DM, F0.9, YZ treatments was higher than those under the other treatments. Output-input ratios of DM, MG, YZ, F0.9 and F0.6 treatments were significantly higher than that of CK. The net income and output-input ratios of DM and MG treatments were significantly higher than those of straw mulching treatments. For moderately saline soils, plastic film mulching was the most effective method. Among the straw mulching treatments, F0.9 treatment was the best mulching method. Compared with the other mulching methods, water retention, salt inhibition, and yield effects of KZ treatment were bad. Thus sunflower straw (KZ) was not a suitable mulching material in the study area. The results of the study were suitable for application in guiding the use of mulching methods in Hetao Irrigation District.
Soil surface mulching with plastic film or crop straws can prevent secondary soil salinization and improve crop water use efficiency (WUE). An experiment was conducted in a moderately saline field to investigate the effects of different mulching methods on soil characteristics and sunflower yield. Seven treatments were conducted in the study, including 9 000 kg·hm-2 chopped maize straw mulching (F0.9), 6 000 kg·hm-2 chopped maize straw mulching (F0.6), whole maize straw mulching (YZ), whole sunflower straw mulching (KZ), plastic film mulching (DM), second-used plastic film mulching (MG) and no mulching (CK). The study analyzed the effects of different mulching methods on soil water and salt movement, sunflower yield and economic benefits of moderately saline soils. The aim of the study was to improve production effects of surface mulching of saline soils. The results showed that salt contents in the 0 5 cm soil layer under treatments of F0.9, YZ and DM decreased while those under MG, F0.6, KZ and CK treatments increased at harvest compared with thoes at sowing. Also salt contents at the 0 20 cm soil layer under F0.9 and DM treatments decreased while those under F0.6, YZ, MG, KZ and CK treatments increased at harvest compared with those at sowing. Different mulching treatments had significantly different effects on soil salt content in the 0 20 cm soil layer. The effects of different mulching methods on soil salt content were inclined to similar with increasing soil depth. In terms of salt content in the 0 20 cm soil layer, F0.9 treatment was the lowest, which suggested that F0.9 treatment had the best salt inhibitory effect. The inhibitory effects on soil salt of mulching measures of DM and F0.6 were similar. For different straw mulching treatments, the inhibitory effects on soil salt of F0.9 and F0.6 were better than those of YZ and KZ. For different plastic film mulching treatments, the inhibitory effect on soil salt of DM was better than that of MG. In the 0 5 cm and 0 20 cm soil layers, average soil water content under DM treatment was higher than those under straw mulching treatments throughout the entire growth period of sunflower. Average soil water content under chopped straw mulching treatments (F0.9 and F0.6) were higher than that under whole straw mulching treatments (YZ and KZ) throughout the growth period. Compared with CK, DM and F0.9 improved 0 100 cm soil water storage significantly. Treatments F0.9 and DM decreased soil water variation coefficients in the 0 100 cm soil layer and thereby maintained stable soil water content throughout the growth season. The order of sunflower yield for different treatments was DM > F0.9 > YZ > F0.6 > MG > KZ > CK. The different mulching methods enhanced crop WUE by improving farmland environment. WUE under DM, F0.9, YZ treatments was higher than those under the other treatments. Output-input ratios of DM, MG, YZ, F0.9 and F0.6 treatments were significantly higher than that of CK. The net income and output-input ratios of DM and MG treatments were significantly higher than those of straw mulching treatments. For moderately saline soils, plastic film mulching was the most effective method. Among the straw mulching treatments, F0.9 treatment was the best mulching method. Compared with the other mulching methods, water retention, salt inhibition, and yield effects of KZ treatment were bad. Thus sunflower straw (KZ) was not a suitable mulching material in the study area. The results of the study were suitable for application in guiding the use of mulching methods in Hetao Irrigation District.
2015, 23(4): 425-431.
doi: 10.13930/j.cnki.cjea.141258
Abstract:
To verify the effects of elevated atmospheric CO2 concentration on photosynthetic capacity of rice leaves, the trend in photosynthetic pigments contents of flag-leaves at late growth stage and yield components of rice varieties of 'Songjing9' and 'Daohuaxiang2' were studied under the free-air CO2 enrichment (FACE) system. Flag-leaf chlorophyll-a, chlorophyll-b and carotenoid contents were measured during booting and heading stages and yield components measured after harvest. The total chlorophyll content and the ratio of chlorophyll-a to chlorophyll-b were calculated and the correlations among yield components analyzed. The results showed that comparing to ABM (ambient CO2) treatment, FACE treatment increased chlorophyll-a contents in flag-leaves of both rice varieties at booting to heading stage with respective peak increasing values of 28.46% and 19.58%, and decreased by 15.25% and 23.20% at 20 d after heading stage. FACE treatment decreased chlorophyll-b contents of flag-leaves of both rice varieties by 7.57% and 5.33% at 20 d after heading stage, then increased at respective rates of 4.19% and 9.46% at 30 d after heading stage. Carotenoid contents in flag-leaves of both rice varieties noticeably increased respectively by 9.47% and 13.55% at heading stage under FACE treatment and then decreased at 10 d after heading stage at rates of 13.54% and 16.67%. The trends in the effects of elevated CO2 concentration on total chlorophyll content and chlorophyll-a to chlorophyll-b ratio of flag-leaf were similar. The trends increased from booting to heading stage and then decreased at 20 d after heading stage. Elevated CO2 concentration was beneficial to yield components by increasing spike number per unit area, seed-setting rate and 1000-grain weight. The 1000-grain weight was increased by 8.6% and 4.5% of the two varieties, respectively. The results suggested that while elevated atmospheric CO2 concentration enhanced photosynthetic pigment accumulation in flag-leaves of rice at booting and heading stages, it inhibited photosynthetic pigment accumulation after heading stage. Photosynthetic pigments of flag-leaves of different varieties of rice had different degrees of responses to elevated atmospheric CO2 concentration. Increased 1000-grain weight was the key factor for yield increase of rice under elevated atmospheric CO2 concentration.
To verify the effects of elevated atmospheric CO2 concentration on photosynthetic capacity of rice leaves, the trend in photosynthetic pigments contents of flag-leaves at late growth stage and yield components of rice varieties of 'Songjing9' and 'Daohuaxiang2' were studied under the free-air CO2 enrichment (FACE) system. Flag-leaf chlorophyll-a, chlorophyll-b and carotenoid contents were measured during booting and heading stages and yield components measured after harvest. The total chlorophyll content and the ratio of chlorophyll-a to chlorophyll-b were calculated and the correlations among yield components analyzed. The results showed that comparing to ABM (ambient CO2) treatment, FACE treatment increased chlorophyll-a contents in flag-leaves of both rice varieties at booting to heading stage with respective peak increasing values of 28.46% and 19.58%, and decreased by 15.25% and 23.20% at 20 d after heading stage. FACE treatment decreased chlorophyll-b contents of flag-leaves of both rice varieties by 7.57% and 5.33% at 20 d after heading stage, then increased at respective rates of 4.19% and 9.46% at 30 d after heading stage. Carotenoid contents in flag-leaves of both rice varieties noticeably increased respectively by 9.47% and 13.55% at heading stage under FACE treatment and then decreased at 10 d after heading stage at rates of 13.54% and 16.67%. The trends in the effects of elevated CO2 concentration on total chlorophyll content and chlorophyll-a to chlorophyll-b ratio of flag-leaf were similar. The trends increased from booting to heading stage and then decreased at 20 d after heading stage. Elevated CO2 concentration was beneficial to yield components by increasing spike number per unit area, seed-setting rate and 1000-grain weight. The 1000-grain weight was increased by 8.6% and 4.5% of the two varieties, respectively. The results suggested that while elevated atmospheric CO2 concentration enhanced photosynthetic pigment accumulation in flag-leaves of rice at booting and heading stages, it inhibited photosynthetic pigment accumulation after heading stage. Photosynthetic pigments of flag-leaves of different varieties of rice had different degrees of responses to elevated atmospheric CO2 concentration. Increased 1000-grain weight was the key factor for yield increase of rice under elevated atmospheric CO2 concentration.
2015, 23(4): 432-440.
doi: 10.13930/j.cnki.cjea.141113
Abstract:
As a major cash crop, cotton has been widely cultivated for several decades in Xinjiang Uygur Autonomous Region (referred to as Xinjiang). Due to continuous cotton cropping over a long period, soil-borne diseases (e.g., Fusarium sp. and Verticillium dahlia) have worsened in cotton fields in recent years, resulting in substantial yield declines. The objective of this study was to determine the effects of long-term cultivation of cotton on soil biological activity, soil microbial community structure, microbial genetic diversity (e.g., total bacterial and total fungi) and specific soil microbe (e.g., fusarium and bacillus). Three cotton treatments [continuous mono-cropping for 5 consecutive years (CtN5), for 10 consecutive years (CtN10) and for 15 consecutive years (CtN15)] were set up in an oasis farmland in northern Xinjiang. Then soil peroxidase, invertase, arylsulfatase, dehydrogenase, and protease activities were measured, while soil microbial community structure diversities of total bacteria, total fungi, fusarium soil-borne pathogenic bacteria and bacillus soil antagonistic bacteria were determined using PCR-DGGE fingerprint approach. There was a significantly decreasing tendency in soil catalase, invertase and dehydrogenase activities with increasing years of continuous cropping. For instance, compared with CtN10, CtN15 treatment decreased activities by 15.0% for catalase and by 6.4% for invertase. However, arylsulfatase and protease activities decreased from continuous cotton cropping of 5 years (CtN5) to 10 years (CtN10) followed by an increasing tendency from continuous cotton cropping of 10 years (CtN10) to 15 years (CtN15). The Shannon-Wiener and Simpson indices of soil total bacteria and total fungi declined markedly with increasing years of continuous cotton cropping. Compared with CtN10, the quantity of soil total bacteria gene band (DGGE fingerprint) decreased by 7.41% under CtN15. It decreased by 1.72% from CtN5 treatment to CtN10 treatment. The values of soil total fungal gene band and Shannon-Wiener diversity index were 78 and 3.22 under CtN15 treatment, suggesting respectively 17.02% and 5.29% decreases under CtN15 compared with CtN5. Compared with CtN10 treatment, the Shannon-Wiener and Simpson indices of soil bacillus community increased respectively by 54.8% and 14.5% under CtN15 treatment. Moreover, the amount of fusarium gene and bacillus gene bands as well as the related diversity indices decreased from CtN5 to CtN10 treatment, but then increased from CtN10 to CtN15. In conclusion therefore, soil enzyme activity and microbial community structure and diversity decreased with increasing years of continuous cotton cropping. Long-term, continuous cultivation of cotton had an adverse effect on soil biological characteristics in northern Xinjiang.
As a major cash crop, cotton has been widely cultivated for several decades in Xinjiang Uygur Autonomous Region (referred to as Xinjiang). Due to continuous cotton cropping over a long period, soil-borne diseases (e.g., Fusarium sp. and Verticillium dahlia) have worsened in cotton fields in recent years, resulting in substantial yield declines. The objective of this study was to determine the effects of long-term cultivation of cotton on soil biological activity, soil microbial community structure, microbial genetic diversity (e.g., total bacterial and total fungi) and specific soil microbe (e.g., fusarium and bacillus). Three cotton treatments [continuous mono-cropping for 5 consecutive years (CtN5), for 10 consecutive years (CtN10) and for 15 consecutive years (CtN15)] were set up in an oasis farmland in northern Xinjiang. Then soil peroxidase, invertase, arylsulfatase, dehydrogenase, and protease activities were measured, while soil microbial community structure diversities of total bacteria, total fungi, fusarium soil-borne pathogenic bacteria and bacillus soil antagonistic bacteria were determined using PCR-DGGE fingerprint approach. There was a significantly decreasing tendency in soil catalase, invertase and dehydrogenase activities with increasing years of continuous cropping. For instance, compared with CtN10, CtN15 treatment decreased activities by 15.0% for catalase and by 6.4% for invertase. However, arylsulfatase and protease activities decreased from continuous cotton cropping of 5 years (CtN5) to 10 years (CtN10) followed by an increasing tendency from continuous cotton cropping of 10 years (CtN10) to 15 years (CtN15). The Shannon-Wiener and Simpson indices of soil total bacteria and total fungi declined markedly with increasing years of continuous cotton cropping. Compared with CtN10, the quantity of soil total bacteria gene band (DGGE fingerprint) decreased by 7.41% under CtN15. It decreased by 1.72% from CtN5 treatment to CtN10 treatment. The values of soil total fungal gene band and Shannon-Wiener diversity index were 78 and 3.22 under CtN15 treatment, suggesting respectively 17.02% and 5.29% decreases under CtN15 compared with CtN5. Compared with CtN10 treatment, the Shannon-Wiener and Simpson indices of soil bacillus community increased respectively by 54.8% and 14.5% under CtN15 treatment. Moreover, the amount of fusarium gene and bacillus gene bands as well as the related diversity indices decreased from CtN5 to CtN10 treatment, but then increased from CtN10 to CtN15. In conclusion therefore, soil enzyme activity and microbial community structure and diversity decreased with increasing years of continuous cotton cropping. Long-term, continuous cultivation of cotton had an adverse effect on soil biological characteristics in northern Xinjiang.
2015, 23(4): 441-446.
doi: 10.13930/j.cnki.cjea.141117
Abstract:
The Medicago sativa L. cv. Huaiyin variety of alfalfa was used to determine the physical changes and related differences in protein expressions of alfalfa in response to heat stress. Electrical conductivity, malonaldehyde content and cell activity were measured in alfalfa seedlings at 25 ℃, 30 ℃, 35 ℃ and 40 ℃ in combination with different durations of heat stress (0 h, 0.5 h, 1 h, 4 h, 12 h and 24 h). In addition, alfalfa seedlings treated at 35 ℃ and 40 ℃ for 24 h were used to analyze differentially expressed protein. The results showed that electrical conductivity of the test samples increased sharply after treatment at 35 ℃ and 40 ℃ for 0.5 h, but declined for treatment durations exceeding 1 h. However, malonaldehyde content of the samples increased for treatment durations exceeding 1 h but gradually declined after 4 h. Cell activity of test samples declined with increasing treatment duration. Screening analysis of the differences in proteins showed 27 significantly different spots after treatment at 35 ℃ for 24 h, 19 of which spots were raised and 5 were new. After treatment at 40 ℃ for 24 h, 51 significantly different spots were observed - 40 out of the 51 spots were raised and 11 were new. Secondary mass spectrum analyses indicated that 4 proteins - 20 kD chaperonin, Hsp70, Hsp23 and Hsp17, were only observed in samples at 40 ℃ for 24 hours. This suggested that the 4 proteins correlated with heat stress defense mechanisms, the samples produced more defense proteins at 40 ℃ to repair damage to alfalfa seedling membranes.
The Medicago sativa L. cv. Huaiyin variety of alfalfa was used to determine the physical changes and related differences in protein expressions of alfalfa in response to heat stress. Electrical conductivity, malonaldehyde content and cell activity were measured in alfalfa seedlings at 25 ℃, 30 ℃, 35 ℃ and 40 ℃ in combination with different durations of heat stress (0 h, 0.5 h, 1 h, 4 h, 12 h and 24 h). In addition, alfalfa seedlings treated at 35 ℃ and 40 ℃ for 24 h were used to analyze differentially expressed protein. The results showed that electrical conductivity of the test samples increased sharply after treatment at 35 ℃ and 40 ℃ for 0.5 h, but declined for treatment durations exceeding 1 h. However, malonaldehyde content of the samples increased for treatment durations exceeding 1 h but gradually declined after 4 h. Cell activity of test samples declined with increasing treatment duration. Screening analysis of the differences in proteins showed 27 significantly different spots after treatment at 35 ℃ for 24 h, 19 of which spots were raised and 5 were new. After treatment at 40 ℃ for 24 h, 51 significantly different spots were observed - 40 out of the 51 spots were raised and 11 were new. Secondary mass spectrum analyses indicated that 4 proteins - 20 kD chaperonin, Hsp70, Hsp23 and Hsp17, were only observed in samples at 40 ℃ for 24 hours. This suggested that the 4 proteins correlated with heat stress defense mechanisms, the samples produced more defense proteins at 40 ℃ to repair damage to alfalfa seedling membranes.
2015, 23(4): 447-453.
doi: 10.13930/j.cnki.cjea.141187
Abstract:
This study used 'Youyu 26' buckwheat cultivar to analyze the effects of exogenous selenium (Se) on agronomic and physiological characteristics of buckwheat seedlings in plumbum (Pb) polluted soil in a pot experiment. The study determined the effects of exogenous Se on Pb content, and growth, development and output of buckwheat under soil Pb stress. The results of the study could lay the theory base for research on the use of Se to alleviate the toxicity of heavy metal Pb in plants. This was critical for developing the methodology needed for producing buckwheat and decreasing heavy mental contamination in agricultural fields. The experiment was set up in a two-factor complete random design, with five concentrations of Se (0 mg·kg-1, 1 mg·kg-1, 2.5 mg·kg-1, 5 mg·kg-1 and 10 mg·kg-1) and three concentrations of Pb (0 mg·L-1, 500 mg·L-1 and 1 000 mg·L-1). The results showed that with increasing concentration of Pb, plant height, total root length, dry weight, total root area, root activity, chlorophyll content, chlorophyll fluorescence parameters and economic yield (1000-grain weight, per-plant grain, etc.) of buckwheat decreased. Low Se concentration (1?2.5 mg·L-1) alleviated Pb toxicity in buckwheat. The synergistic effect of high concentration of Se (5-10 mg·L-1) increased Pb toxicity in buckwheat. Buckwheat total root length, root area, root activity and photosynthetic characteristics were highest and SOD and POD activities lowest at Se concentration of 2.5 mg·L-1. Economic yield of buckwheat was highest when Pb tolerance of all organs of mature buckwheat was lowest at Se concentration of 2.5 mg·L-1. Under the same Pb concentration, the Pb content in organs of buckwheat was decreased first and then increased with increased Se concentration. The Pb contents in different organs of buckwheat followed the order of root > stem > leaf > seeds under each treatment. Thus exogenous Se could be used to enhance buckwheat tolerance to Pb stress by inhabiting buckwheat absorption and transportation of Pb, promoting leaf photosynthesis and chlorophyll content along with root activity of seedling buckwheat. The research showed that suitable amount of Se (a recommended concentration of 2.5 mg·L-1) could alleviate heavy metal toxicity in buckwheat.
This study used 'Youyu 26' buckwheat cultivar to analyze the effects of exogenous selenium (Se) on agronomic and physiological characteristics of buckwheat seedlings in plumbum (Pb) polluted soil in a pot experiment. The study determined the effects of exogenous Se on Pb content, and growth, development and output of buckwheat under soil Pb stress. The results of the study could lay the theory base for research on the use of Se to alleviate the toxicity of heavy metal Pb in plants. This was critical for developing the methodology needed for producing buckwheat and decreasing heavy mental contamination in agricultural fields. The experiment was set up in a two-factor complete random design, with five concentrations of Se (0 mg·kg-1, 1 mg·kg-1, 2.5 mg·kg-1, 5 mg·kg-1 and 10 mg·kg-1) and three concentrations of Pb (0 mg·L-1, 500 mg·L-1 and 1 000 mg·L-1). The results showed that with increasing concentration of Pb, plant height, total root length, dry weight, total root area, root activity, chlorophyll content, chlorophyll fluorescence parameters and economic yield (1000-grain weight, per-plant grain, etc.) of buckwheat decreased. Low Se concentration (1?2.5 mg·L-1) alleviated Pb toxicity in buckwheat. The synergistic effect of high concentration of Se (5-10 mg·L-1) increased Pb toxicity in buckwheat. Buckwheat total root length, root area, root activity and photosynthetic characteristics were highest and SOD and POD activities lowest at Se concentration of 2.5 mg·L-1. Economic yield of buckwheat was highest when Pb tolerance of all organs of mature buckwheat was lowest at Se concentration of 2.5 mg·L-1. Under the same Pb concentration, the Pb content in organs of buckwheat was decreased first and then increased with increased Se concentration. The Pb contents in different organs of buckwheat followed the order of root > stem > leaf > seeds under each treatment. Thus exogenous Se could be used to enhance buckwheat tolerance to Pb stress by inhabiting buckwheat absorption and transportation of Pb, promoting leaf photosynthesis and chlorophyll content along with root activity of seedling buckwheat. The research showed that suitable amount of Se (a recommended concentration of 2.5 mg·L-1) could alleviate heavy metal toxicity in buckwheat.
WANG Jianpan,
QIN Sheng,
LIU Feifei,
KE Shengbing,
ZHOU Xiazhi,
BI Shoudong,
ZOU Yunding,
DANG Fenghua,
XU Jinfeng,
YU Kun,
ZHAO Xuejuan
2015, 23(4): 454-464.
doi: 10.13930/j.cnki.cjea.141110
Abstract:
Although somehow influenced by sampling size, the aggregated intensity index was used to assess the spatial distribution of pests and their natural enemies and eventually used to determine the relationship between pests and their natural enemies. To analysis the degree of closeness of the spatial relations of natural enemies to Dialeurodes citri and the cause-range aggregation, the block-quadrat variance analysis, grey correlaiton analysis, aggregated intensity index analysis, aggregated population mean analysis and the ρ index analysis were used to study D. citri and 6 of its dominant natural enemies from a total of 11 species of natural enemies under different poly block sizes (namely, different basic quadrats numbers in a poly block) in tea gardens in Qianshan Area, Anhui Province. The study may provide scientific basis for determining the dominant natural enemy species of D. citri. The grey correlation degree analysis showed that the most closely followed natural enemies of D. citri were Erigonidium graminicolum (0.848 6), Theridion octomaculatum (0.840 6) and Propylaea japonica (0.805 5). However, the spatial following relation of Chilocorus kuwanae (0.764 2) with D. citri was not so close. The synthetic block-quadrat variance and aggregate intensity analysis results suggested that by increasing basic quadrat number within the poly block from 1 to 8, the diffusion coefficient C of aggregation pattern increased, while the diffusion coefficient C of uniform and random aggregation patterns decreased. In addition, the aggregation degree of spatial distribution of D. citri and its natural enemies had no significant difference between basic quadrat number 1 and basic quadrat number 2, 4, 8, 16 and 32. The average λ of D. citri was higher than 2, suggesting self-aggregation of D. citri. When average λ was positive, the gathering average of population steadily increased with increasing basic quadrat number within the poly block. The ρ index analysis suggested that the minimum area of aggregation pattern of D. citri was one basic quadrat of 1.7 m2. Put together, the results provided a critical basis for further protection of natural enemies and determination of suitable quadrat sizes of pest sampling.
Although somehow influenced by sampling size, the aggregated intensity index was used to assess the spatial distribution of pests and their natural enemies and eventually used to determine the relationship between pests and their natural enemies. To analysis the degree of closeness of the spatial relations of natural enemies to Dialeurodes citri and the cause-range aggregation, the block-quadrat variance analysis, grey correlaiton analysis, aggregated intensity index analysis, aggregated population mean analysis and the ρ index analysis were used to study D. citri and 6 of its dominant natural enemies from a total of 11 species of natural enemies under different poly block sizes (namely, different basic quadrats numbers in a poly block) in tea gardens in Qianshan Area, Anhui Province. The study may provide scientific basis for determining the dominant natural enemy species of D. citri. The grey correlation degree analysis showed that the most closely followed natural enemies of D. citri were Erigonidium graminicolum (0.848 6), Theridion octomaculatum (0.840 6) and Propylaea japonica (0.805 5). However, the spatial following relation of Chilocorus kuwanae (0.764 2) with D. citri was not so close. The synthetic block-quadrat variance and aggregate intensity analysis results suggested that by increasing basic quadrat number within the poly block from 1 to 8, the diffusion coefficient C of aggregation pattern increased, while the diffusion coefficient C of uniform and random aggregation patterns decreased. In addition, the aggregation degree of spatial distribution of D. citri and its natural enemies had no significant difference between basic quadrat number 1 and basic quadrat number 2, 4, 8, 16 and 32. The average λ of D. citri was higher than 2, suggesting self-aggregation of D. citri. When average λ was positive, the gathering average of population steadily increased with increasing basic quadrat number within the poly block. The ρ index analysis suggested that the minimum area of aggregation pattern of D. citri was one basic quadrat of 1.7 m2. Put together, the results provided a critical basis for further protection of natural enemies and determination of suitable quadrat sizes of pest sampling.
2015, 23(4): 465-472.
doi: 10.13930/j.cnki.cjea.141147
Abstract:
Acyrthosiphon pisum is one of the most devastating pests of alfalfa (Medicago sativa L.) in China. Using micro-satellite markers, we studied the genetic similarity and genetic differentiation among the pest geo-populations, and their relationships with genetic distance, geographical distance and elevation. We also evaluated genetic structure of ten A. pisum (green form) populations in different regions of China (Beijing City, Inner Mongolia Autonomous Region, Ningxia Hui Autonomous Region, Xinjiang Uygur Autonomous Region, and Gansu, Shaanxi, Shandong, Henan, Shanxi and Qinghai Provinces). A total of 41 (100%) polymorphic bands were detected using 15 pairs of SSR primers in 300 individuals across 10 populations. The number of observed alleles (Na) per locus was 1.592 7 and that of effective alleles (Ne) was 1.356 9, with Nei's genetic diversity (H) of 0.206 6 and Shannon-Wiener diversity index (I) of 0.307 6. Populations from Xinjiang Uygur Autonomous Region, Shaanxi Province and Henan Province showed strong genetic diversity. In contrast, genetic diversity of Mongolia Autonomous Region, Shandong Province and Qinghai Province populations was much weak. Overall, there was a high genetic divergence among the 10 A. pisum populations (Gst = 0.399 6). Based on cluster analysis, the 10 A. pisum populations were divided into two distinct clusters. Cluster one (i) consisted of the populations from Shandong and Henan Provinces, while cluster two (ii) consisted of the populations from Beijing City, Inner Mongolia Autonomous Region, Ningxia Hui Autonomous Region, Xinjiang Uygur Autonomous Region, and Gansu, Shaanxi, Shanxi and Qinghai Provinces. Mantel-test analysis showed that genetic distance of A. pisum was no significantly correlated with geographic distance and elevation. As A. pisum (green form) population showed relatively high genetic diversity in China, there was the need to strengthen monitoring and management of pea aphids.
Acyrthosiphon pisum is one of the most devastating pests of alfalfa (Medicago sativa L.) in China. Using micro-satellite markers, we studied the genetic similarity and genetic differentiation among the pest geo-populations, and their relationships with genetic distance, geographical distance and elevation. We also evaluated genetic structure of ten A. pisum (green form) populations in different regions of China (Beijing City, Inner Mongolia Autonomous Region, Ningxia Hui Autonomous Region, Xinjiang Uygur Autonomous Region, and Gansu, Shaanxi, Shandong, Henan, Shanxi and Qinghai Provinces). A total of 41 (100%) polymorphic bands were detected using 15 pairs of SSR primers in 300 individuals across 10 populations. The number of observed alleles (Na) per locus was 1.592 7 and that of effective alleles (Ne) was 1.356 9, with Nei's genetic diversity (H) of 0.206 6 and Shannon-Wiener diversity index (I) of 0.307 6. Populations from Xinjiang Uygur Autonomous Region, Shaanxi Province and Henan Province showed strong genetic diversity. In contrast, genetic diversity of Mongolia Autonomous Region, Shandong Province and Qinghai Province populations was much weak. Overall, there was a high genetic divergence among the 10 A. pisum populations (Gst = 0.399 6). Based on cluster analysis, the 10 A. pisum populations were divided into two distinct clusters. Cluster one (i) consisted of the populations from Shandong and Henan Provinces, while cluster two (ii) consisted of the populations from Beijing City, Inner Mongolia Autonomous Region, Ningxia Hui Autonomous Region, Xinjiang Uygur Autonomous Region, and Gansu, Shaanxi, Shanxi and Qinghai Provinces. Mantel-test analysis showed that genetic distance of A. pisum was no significantly correlated with geographic distance and elevation. As A. pisum (green form) population showed relatively high genetic diversity in China, there was the need to strengthen monitoring and management of pea aphids.
2015, 23(4): 473-481.
doi: 10.13930/j.cnki.cjea.141277
Abstract:
Significant climate change has occurred across the North China Plain in the past few decades, corresponding to global climate change. Climate change during the growth period of summer maize has caused far-reaching impacts on production in the region, which is one of the most vital summer maize production regions in China. Based on observation data from 49 meteorological stations and 27 agro-meteorological stations, this paper analyzed growth degree days (GDD), heat degree days (HDD) and rainfall, and their climatic trend rates for the vegetative growth phase, vegetative and reproductive growth phase, productive growth phase and whole growth period of summer maize in the North China Plain for the period 1961?2010. The results showed that both GDD and HDD increased from northeast to southwest of the North China Plain. However, rainfall decreased from southeast to northwest of the plain. The climatic trend rates of GDD, HDD and rainfall from 1961 to 2010 in the North China Plain were 8.14 ℃·d·10a-1, 2.45 ℃·d·10a-1 and 10.75 mm·10a-1, respectively. Furthermore, GDD decreased during the vegetative growth phase, increased during vegetative and reproductive growth phase, reproductive growth phase and whole growth period of summer maize in northern region of the North China Plain for the period 1961-2010. However, the reverse trends were noted for the southern of the plain. HDD increased in the north but decreased in the southern of the North China Plain. Rainfall decreased in the north but increased in the south for all the growth stages. Consequently, high temperature and drought posed significant risks to summer maize production in the north Hebei Province, Beijing City and Tianjin City in the north of the North China Plain. However, the risks of temperature and drought decreased for most of Henan Province and southern Shandong Province in the south of the North China Plain for the period 1961-2010.
Significant climate change has occurred across the North China Plain in the past few decades, corresponding to global climate change. Climate change during the growth period of summer maize has caused far-reaching impacts on production in the region, which is one of the most vital summer maize production regions in China. Based on observation data from 49 meteorological stations and 27 agro-meteorological stations, this paper analyzed growth degree days (GDD), heat degree days (HDD) and rainfall, and their climatic trend rates for the vegetative growth phase, vegetative and reproductive growth phase, productive growth phase and whole growth period of summer maize in the North China Plain for the period 1961?2010. The results showed that both GDD and HDD increased from northeast to southwest of the North China Plain. However, rainfall decreased from southeast to northwest of the plain. The climatic trend rates of GDD, HDD and rainfall from 1961 to 2010 in the North China Plain were 8.14 ℃·d·10a-1, 2.45 ℃·d·10a-1 and 10.75 mm·10a-1, respectively. Furthermore, GDD decreased during the vegetative growth phase, increased during vegetative and reproductive growth phase, reproductive growth phase and whole growth period of summer maize in northern region of the North China Plain for the period 1961-2010. However, the reverse trends were noted for the southern of the plain. HDD increased in the north but decreased in the southern of the North China Plain. Rainfall decreased in the north but increased in the south for all the growth stages. Consequently, high temperature and drought posed significant risks to summer maize production in the north Hebei Province, Beijing City and Tianjin City in the north of the North China Plain. However, the risks of temperature and drought decreased for most of Henan Province and southern Shandong Province in the south of the North China Plain for the period 1961-2010.
2015, 23(4): 482-489.
doi: 10.13930/j.cnki.cjea.141212
Abstract:
Water is in severe shortage in Heilonggang region, a region where insufficient and uneven precipitation are the main limiting factors to stable production of winter wheat. Thus to lay the theoretical basis for stable winter wheat production in the region under optimal irrigation, a study was conducted on the trends in water deficit in recent 30 years in Wuqiao County, Heibei Province. Based on observed daily meteorological data in Wuqiao County, we analyzed the dynamics of precipitation, crop water requirement, crop water consumption intensity and crop water deficit index (CWDI) for the whole growth period and the individual growth stages of winter wheat from 1981 to 2013 using SIMETAW model. To calculate the coefficient of variation of winter wheat yield reduction in different precipitation years, we divided winter wheat yield into trend yield and meteorological yield using linear moving average. The results of the study showed that CWDI and crop water requirement for the whole growth period of winter wheat gradually increased with time. The probability of the occurrence of drought in the whole growth period of winter wheat was 93.75% in the analyzed 32 years. Of this, the probability of both moderate drought and severe drought was 65.52%. Precipitation decreased in the middle stages of winter wheat growth while it increased in the late stages of winter wheat growth. The trend in daily crop water consumption intensity was the reverse of that of precipitation. The trends in both precipitation and crop water consumption intensity resulted in higher CWDI during greening to jointing and then jointing to flowering stages than in the other growth stages of winter wheat. The absolute value of coefficient of variation of yield reduction of winter wheat was highest (154.241) for dry years, lowest (1.999) for humid years and average (24.776) for normal years. Timing irrigation at jointing through flowering stage was critical for ensuring a stable increase in winter wheat production. Thus to ensure stable yield production in the study area, an adequately irrigation at the beginning of jointing stage or twice irrigations at the early and late jointing stage of winter wheat were required.
Water is in severe shortage in Heilonggang region, a region where insufficient and uneven precipitation are the main limiting factors to stable production of winter wheat. Thus to lay the theoretical basis for stable winter wheat production in the region under optimal irrigation, a study was conducted on the trends in water deficit in recent 30 years in Wuqiao County, Heibei Province. Based on observed daily meteorological data in Wuqiao County, we analyzed the dynamics of precipitation, crop water requirement, crop water consumption intensity and crop water deficit index (CWDI) for the whole growth period and the individual growth stages of winter wheat from 1981 to 2013 using SIMETAW model. To calculate the coefficient of variation of winter wheat yield reduction in different precipitation years, we divided winter wheat yield into trend yield and meteorological yield using linear moving average. The results of the study showed that CWDI and crop water requirement for the whole growth period of winter wheat gradually increased with time. The probability of the occurrence of drought in the whole growth period of winter wheat was 93.75% in the analyzed 32 years. Of this, the probability of both moderate drought and severe drought was 65.52%. Precipitation decreased in the middle stages of winter wheat growth while it increased in the late stages of winter wheat growth. The trend in daily crop water consumption intensity was the reverse of that of precipitation. The trends in both precipitation and crop water consumption intensity resulted in higher CWDI during greening to jointing and then jointing to flowering stages than in the other growth stages of winter wheat. The absolute value of coefficient of variation of yield reduction of winter wheat was highest (154.241) for dry years, lowest (1.999) for humid years and average (24.776) for normal years. Timing irrigation at jointing through flowering stage was critical for ensuring a stable increase in winter wheat production. Thus to ensure stable yield production in the study area, an adequately irrigation at the beginning of jointing stage or twice irrigations at the early and late jointing stage of winter wheat were required.
2015, 23(4): 490-496.
doi: 10.13930/j.cnki.cjea.141086
Abstract:
Both Hunan and Hubei Provinces are major agricultural regions. Rice production is not only related to food security in the two provinces, but also importantly influences food security in China. Water resources in the two provinces will further decline due to the South-North Water Transfer project. Reference crop evapotranspiration (ET0) is the key factor for estimating vegetation evapotranspiration. Accurate estimation of ET0 is essential for water resources management and irrigation schedule. The adapted FAO-56 Penman Monteith (P-M) equation has been recommended as the reference equation for estimating ET0 and for calibrating other ET0 equations. The main drawback of using the P-M equation is the requirement for a range of meteorological inputs (air temperature, relative humidity, solar radiation and wind speed). However, the number of meteorological stations is limited even in developed countries, where meteorological variables are more accurately measured. As ET0 is correlated with geographical location, this study investigated the suitability of Gene-Expression Programming (GEP) technique for modeling ET0 using readily available geographical location information for Hunan and Hubei Provinces. Monthly observation data for 1955 2005 from 46 stations in Hunan and Hubei Provinces were used. The dataset, including monthly maximum temperature, minimum temperature, average wind speed, sunshine duration and relative humidity, were used to model ET0 based on the FAO-56 P-M equation as the reference equation. While the GEP was trained using latitude, longitude, altitude variables and month count as input, monthly ET0 was as output. The GEP model proved to have an adequate precision, with the coefficient of determination (R2) and root mean square error (RMSE) for the validation and test analyses of 0.934, 0.951 and 10.050 mm, 8.628 mm, respectively. Through comparison with the Hargreaves and Priestley-Taylor methods, the GEP model had the lowest RMSE values (8.628 9.967 mm). As the GEP technique could produce a simple and explicit mathematical algorithm, irrigation technicians in data-poor regions could use the GEP model to easily estimate ET0 with adequate precision. It was inferred that ET0 could be calculated using geographical location information in Hunan and Hubei Provinces. The GEP model could simplify monthly irrigation schedule and vegetation evapotranspiration estimation.
Both Hunan and Hubei Provinces are major agricultural regions. Rice production is not only related to food security in the two provinces, but also importantly influences food security in China. Water resources in the two provinces will further decline due to the South-North Water Transfer project. Reference crop evapotranspiration (ET0) is the key factor for estimating vegetation evapotranspiration. Accurate estimation of ET0 is essential for water resources management and irrigation schedule. The adapted FAO-56 Penman Monteith (P-M) equation has been recommended as the reference equation for estimating ET0 and for calibrating other ET0 equations. The main drawback of using the P-M equation is the requirement for a range of meteorological inputs (air temperature, relative humidity, solar radiation and wind speed). However, the number of meteorological stations is limited even in developed countries, where meteorological variables are more accurately measured. As ET0 is correlated with geographical location, this study investigated the suitability of Gene-Expression Programming (GEP) technique for modeling ET0 using readily available geographical location information for Hunan and Hubei Provinces. Monthly observation data for 1955 2005 from 46 stations in Hunan and Hubei Provinces were used. The dataset, including monthly maximum temperature, minimum temperature, average wind speed, sunshine duration and relative humidity, were used to model ET0 based on the FAO-56 P-M equation as the reference equation. While the GEP was trained using latitude, longitude, altitude variables and month count as input, monthly ET0 was as output. The GEP model proved to have an adequate precision, with the coefficient of determination (R2) and root mean square error (RMSE) for the validation and test analyses of 0.934, 0.951 and 10.050 mm, 8.628 mm, respectively. Through comparison with the Hargreaves and Priestley-Taylor methods, the GEP model had the lowest RMSE values (8.628 9.967 mm). As the GEP technique could produce a simple and explicit mathematical algorithm, irrigation technicians in data-poor regions could use the GEP model to easily estimate ET0 with adequate precision. It was inferred that ET0 could be calculated using geographical location information in Hunan and Hubei Provinces. The GEP model could simplify monthly irrigation schedule and vegetation evapotranspiration estimation.
2015, 23(4): 497-505.
doi: 10.13930/j.cnki.cjea.141505
Abstract:
Agricultural land uses affect land surface energy and water balance. The North China Plain (NCP) is one of the most important agricultural regions in China and is experiencing a severe water shortage due to decades of excessive extraction of groundwater for crop irrigation. The precise determination of the distribution of the land areas under different crops in NCP does not only provide the basic information needed for evaluating agricultural water consumption in space but also improve agricultural planning for sustainable water resources management. In this study, we established a method for agricultural land use classification using MODIS NDVI data time-series. Raw 16-day composite NDVI data were first processed using HANTS filtering and then sampled the time-series pattern of NDVI for different croplands based on ground truth data. The typical phenological characteristics of the main crops were determined based on field-monitored phenological data in agro-meteorological stations in the study area. Then multiple cropping index (MCI) was induced based on the NDVI time-series to distinguish land areas under wheat-corn double cropping system. Finally, the cultivated area under winter wheat in NCP for the period of 2000-2013 was extracted by using the CART algorithm. The result was validated with county agricultural statistics data, which showed a statistically significant correlation for the 13-year period with correlation coefficient of 0.94 at 95% confidence level. The probability of consistency less than 40% between the remote-sensing derived cultivated area and agricultural statistics data for the study period was less than 15% for the municipalities in the study area. Agricultural land use frequently changed (about yearly) due to crop rotation, price fluctuation, water limitation, etc. This made it difficult to evaluate agricultural land use change from only comparison of agricultural land use maps for any set of years. Thus in this study, the land use change for different crops was evaluated based on multi-year cropping probability comparison, which composed of actual counts of number of years of wheat cultivation in the study period, with high cultivation probability reflecting dominant crop distribution. Through comparison of the differences in wheat cultivated probability maps for the periods of 2000-2006 and 2007-2013, it was noted that wheat cultivated areas significantly increased in Henan and Shandong Provinces, but significantly decreased in the north part and Heilonggang region of Hebei Plain. These changes were mainly considered to be driven by groundwater conditions and national policies for increased grain production, leading to extensive land reclamation in Henan and Shandong.
Agricultural land uses affect land surface energy and water balance. The North China Plain (NCP) is one of the most important agricultural regions in China and is experiencing a severe water shortage due to decades of excessive extraction of groundwater for crop irrigation. The precise determination of the distribution of the land areas under different crops in NCP does not only provide the basic information needed for evaluating agricultural water consumption in space but also improve agricultural planning for sustainable water resources management. In this study, we established a method for agricultural land use classification using MODIS NDVI data time-series. Raw 16-day composite NDVI data were first processed using HANTS filtering and then sampled the time-series pattern of NDVI for different croplands based on ground truth data. The typical phenological characteristics of the main crops were determined based on field-monitored phenological data in agro-meteorological stations in the study area. Then multiple cropping index (MCI) was induced based on the NDVI time-series to distinguish land areas under wheat-corn double cropping system. Finally, the cultivated area under winter wheat in NCP for the period of 2000-2013 was extracted by using the CART algorithm. The result was validated with county agricultural statistics data, which showed a statistically significant correlation for the 13-year period with correlation coefficient of 0.94 at 95% confidence level. The probability of consistency less than 40% between the remote-sensing derived cultivated area and agricultural statistics data for the study period was less than 15% for the municipalities in the study area. Agricultural land use frequently changed (about yearly) due to crop rotation, price fluctuation, water limitation, etc. This made it difficult to evaluate agricultural land use change from only comparison of agricultural land use maps for any set of years. Thus in this study, the land use change for different crops was evaluated based on multi-year cropping probability comparison, which composed of actual counts of number of years of wheat cultivation in the study period, with high cultivation probability reflecting dominant crop distribution. Through comparison of the differences in wheat cultivated probability maps for the periods of 2000-2006 and 2007-2013, it was noted that wheat cultivated areas significantly increased in Henan and Shandong Provinces, but significantly decreased in the north part and Heilonggang region of Hebei Plain. These changes were mainly considered to be driven by groundwater conditions and national policies for increased grain production, leading to extensive land reclamation in Henan and Shandong.
2015, 23(4): 506-513.
doi: 10.13930/j.cnki.cjea.141208
Abstract:
This research evaluated ecological and climatic conditions in rice cultivation region of Sichuan Province and analyzed spatial distributions of those conditions in the region. The study aimed to provide a theoretical basis for rice quality improvement through optimization of rice cultivation region. Ecotone-based field experiments in Sichuan, Yunnan, Guizhou and Chongqing were conducted, based on which a regression model was established for relationship between full heading stage of high-quality rice and longitude, latitude and altitude. Statistical analysis of weather data and spatial interpolation in Geographic Information System (GIS) were used to study the adaptability of high quality rice to the climate and ecology in rice cultivation zones in Sichuan. Furthermore, the spatial distribution of high quality rice production zones in Sichuan was analyzed. The results showed significant regional specialties for high quality rice production in various rice cultivation zones in Sichuan. Through regression analysis between critical periods of rice growth and certain environmental and climatic factors, a regression model was established for relationship between full heading stage of high-quality rice and longitude, latitude and altitude. Besides, meteorological factors which remarkably affected rice growth and quality development were screened in the study areas. Mean daily temperature, percent sunshine, solar radiation and vapor pressure of the 30-day period after full heading stage was regarded as strong evaluation indices of climatic and ecological regionalization of high quality rice cultivation. A comprehensive evaluation model was developed for ecological adaptability of high quality rice in Sichuan rice cultivation zones. Based on the model, ecological and climatic adaptability of high quality rice in each rice cultivation zone in Sichuan were graded and the regional spatial distribution determined. The most suitable regions for high quality rice cultivation were mainly distributed in the northwest periphery of Sichuan Basin, the western and northern regions of the basin and most of the southwest mountain region (except the west part). Besides, odd pieces of land in the southwest and northeast on the periphery of Sichuan Basin were also suitable for high quality rice cultivation. Some areas such as the north and southwest on the periphery of Sichuan Basin, the east and south of the plain region in the west of the basin, the northwest and northeast of the shallow hill region in the center region of the basin, and the west of the mountain region in the southwest were classified as second high quality rice cultivation regions. This study thus provided scientific basis for optimizing the layout and structure of high quality rice production in Sichuan.
This research evaluated ecological and climatic conditions in rice cultivation region of Sichuan Province and analyzed spatial distributions of those conditions in the region. The study aimed to provide a theoretical basis for rice quality improvement through optimization of rice cultivation region. Ecotone-based field experiments in Sichuan, Yunnan, Guizhou and Chongqing were conducted, based on which a regression model was established for relationship between full heading stage of high-quality rice and longitude, latitude and altitude. Statistical analysis of weather data and spatial interpolation in Geographic Information System (GIS) were used to study the adaptability of high quality rice to the climate and ecology in rice cultivation zones in Sichuan. Furthermore, the spatial distribution of high quality rice production zones in Sichuan was analyzed. The results showed significant regional specialties for high quality rice production in various rice cultivation zones in Sichuan. Through regression analysis between critical periods of rice growth and certain environmental and climatic factors, a regression model was established for relationship between full heading stage of high-quality rice and longitude, latitude and altitude. Besides, meteorological factors which remarkably affected rice growth and quality development were screened in the study areas. Mean daily temperature, percent sunshine, solar radiation and vapor pressure of the 30-day period after full heading stage was regarded as strong evaluation indices of climatic and ecological regionalization of high quality rice cultivation. A comprehensive evaluation model was developed for ecological adaptability of high quality rice in Sichuan rice cultivation zones. Based on the model, ecological and climatic adaptability of high quality rice in each rice cultivation zone in Sichuan were graded and the regional spatial distribution determined. The most suitable regions for high quality rice cultivation were mainly distributed in the northwest periphery of Sichuan Basin, the western and northern regions of the basin and most of the southwest mountain region (except the west part). Besides, odd pieces of land in the southwest and northeast on the periphery of Sichuan Basin were also suitable for high quality rice cultivation. Some areas such as the north and southwest on the periphery of Sichuan Basin, the east and south of the plain region in the west of the basin, the northwest and northeast of the shallow hill region in the center region of the basin, and the west of the mountain region in the southwest were classified as second high quality rice cultivation regions. This study thus provided scientific basis for optimizing the layout and structure of high quality rice production in Sichuan.
2015, 23(4): 514-524.
doi: 10.13930/j.cnki.cjea.141036
Abstract:
As performance evaluation is critical for improving land consolidation projects, it is vital to construct and choose an evaluation system suitable for different land consolidation projects. Based on the 2011?2015 Land Consolidation Plan in Sichuan Province, this paper selected 4 typical land consolidation projects in 4 counties (Cangxi County, Hongya County, Gulin County and Yanyuan County) of the province and used the IPOE (input, process, output, effect) evaluation framework to build an evaluation system. The paper then used the entropy weight method to verify the index weight and matter-element method to establish the matter-element evaluation model used to evaluate the performance of the land consolidation project. The results showed that: 1) the performance levels (correlation degrees) of the land consolidation projects in Cangxi County, Hongya County, Gulin County and Yanyuan County were respectively graded as excellent (0.214 0), excellent (0.316 4), excellent (0.401 8) and poor ( 1.914 9). 2) The logical model used in the evaluation framework to establish the evaluation index system was consistent with the concept of comprehensive performance and thus conducive for comprehensive evaluation of land consolidation projects performance. Thus the matter-element analysis was suitable for evaluation of the performance of different land consolidation projects. On this basis, the evaluation of the performance of land consolidation projects in Sichuan was to some extent practical and suitable. 3) Although the land consolidation projects in Sichuan Province had achieved significant results, there was still need to strengthen macro and micro bases of the project. This required shifting from capital investment and organizational management to scientific development suitable for construction designs. At the same time, there was the need to strengthen system construction in order to ensure the completion of the land consolidation projects in timely, qualitative and quantitative manner. More scientific, environmentally-friendly and resource-saving construction design and process could significantly improve the performance of project construction. Furthermore, the suitable scale of management of agricultural lands after consolidation and the development characteristic of agriculture were possible ways of increasing agricultural income to ensure greater public satisfaction. It was only by the above measures that the performance of the land consolidation projects could be improved.
As performance evaluation is critical for improving land consolidation projects, it is vital to construct and choose an evaluation system suitable for different land consolidation projects. Based on the 2011?2015 Land Consolidation Plan in Sichuan Province, this paper selected 4 typical land consolidation projects in 4 counties (Cangxi County, Hongya County, Gulin County and Yanyuan County) of the province and used the IPOE (input, process, output, effect) evaluation framework to build an evaluation system. The paper then used the entropy weight method to verify the index weight and matter-element method to establish the matter-element evaluation model used to evaluate the performance of the land consolidation project. The results showed that: 1) the performance levels (correlation degrees) of the land consolidation projects in Cangxi County, Hongya County, Gulin County and Yanyuan County were respectively graded as excellent (0.214 0), excellent (0.316 4), excellent (0.401 8) and poor ( 1.914 9). 2) The logical model used in the evaluation framework to establish the evaluation index system was consistent with the concept of comprehensive performance and thus conducive for comprehensive evaluation of land consolidation projects performance. Thus the matter-element analysis was suitable for evaluation of the performance of different land consolidation projects. On this basis, the evaluation of the performance of land consolidation projects in Sichuan was to some extent practical and suitable. 3) Although the land consolidation projects in Sichuan Province had achieved significant results, there was still need to strengthen macro and micro bases of the project. This required shifting from capital investment and organizational management to scientific development suitable for construction designs. At the same time, there was the need to strengthen system construction in order to ensure the completion of the land consolidation projects in timely, qualitative and quantitative manner. More scientific, environmentally-friendly and resource-saving construction design and process could significantly improve the performance of project construction. Furthermore, the suitable scale of management of agricultural lands after consolidation and the development characteristic of agriculture were possible ways of increasing agricultural income to ensure greater public satisfaction. It was only by the above measures that the performance of the land consolidation projects could be improved.
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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