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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. 7
Display Method:
2015, 23(7): 793-802.
doi: 10.13930/j.cnki.cjea.141399
Abstract:
The development of organic industry is closely related with the regional ecological environment, and ecological environmental impact assessment of this type of industry is critical for balanced economic performance with full ecological and environmental consideration. Based on the analysis of environmental requirements of organic products, the paper reviewed the effects of organic industry on different eco-environmental factors, and analyzed the full processes characteristics of influence of organic industrial chain on ecology and environment along with the environmental impacts of each node of organic industry. Based on different types of organic industry, a relational coupling of organic industry and ecological environment was analyzed. Furthermore, a comparison between environmental impacts of organic agriculture and those of conventional agriculture showed some significant ecological environmental advantages of organic agriculture. In terms of environmental benefits, the results showed that the effect of organic agriculture on the environment was 68% while that of conventional agriculture was 50%. The full process of current analysis was based on resource consumption, environmental load, energy use, economic cost and human health, driven by the concept of life cycle assessment (LCA). Moreover, ecological index was used to quantitatively characterize organic industrial environmental impacts by classifying multi-factor indicators and computing individual weights to construct the evaluation system. Because of complexity of data acquisition and immaturity of organic industry, the evaluation system of influence of organic industry on the ecology and environment needed further exploration.
The development of organic industry is closely related with the regional ecological environment, and ecological environmental impact assessment of this type of industry is critical for balanced economic performance with full ecological and environmental consideration. Based on the analysis of environmental requirements of organic products, the paper reviewed the effects of organic industry on different eco-environmental factors, and analyzed the full processes characteristics of influence of organic industrial chain on ecology and environment along with the environmental impacts of each node of organic industry. Based on different types of organic industry, a relational coupling of organic industry and ecological environment was analyzed. Furthermore, a comparison between environmental impacts of organic agriculture and those of conventional agriculture showed some significant ecological environmental advantages of organic agriculture. In terms of environmental benefits, the results showed that the effect of organic agriculture on the environment was 68% while that of conventional agriculture was 50%. The full process of current analysis was based on resource consumption, environmental load, energy use, economic cost and human health, driven by the concept of life cycle assessment (LCA). Moreover, ecological index was used to quantitatively characterize organic industrial environmental impacts by classifying multi-factor indicators and computing individual weights to construct the evaluation system. Because of complexity of data acquisition and immaturity of organic industry, the evaluation system of influence of organic industry on the ecology and environment needed further exploration.
2015, 23(7): 803-811.
doi: 10.13930/j.cnki.cjea.150007
Abstract:
Agro-ecosystem is one of the terrestrial ecosystems under intensive control and human disturbance. The estimation of carbon (C) source or sink in agro-ecosystems is a focal research in global C-cycle studies. As carbon dioxide (CO2) is generally the main greenhouse gas with significant effect on climate change, there has been a growing interest in analyzing and understanding C-flux from agro-ecosystems as affected by regional environmental conditions. To determine diurnal and seasonal variations in net ecosystem exchange (NEE) and to explore the effects of environmental factors, CO2 flux was contAgro-ecosystem is one of the terrestrial ecosystems under intensive control and human disturbance. The estimation of carbon (C) source or sink in agro-ecosystems is a focal research in global C-cycle studies. As carbon dioxide (CO2) is generally the main greenhouse gas with significant effect on climate change, there has been a growing interest in analyzing and understanding C-flux from agro-ecosystems as affected by regional environmental conditions. To determine diurnal and seasonal variations in net ecosystem exchange (NEE) and to explore the effects of environmental factors, CO2 flux was continuously measured in 20112012 using the eddy covariance technique in rice-wheat rotation system in the Yangtze River Delta. During the study, eddy covariance measurement together with measurements of various soil and meteorological conditions were taken for two full growing seasons per year. To derive complete time series of NEE, flux partitioning and gap-filling methods were devised. The results showed significant trends of monthly average diurnal and seasonal variations in NEE in rice-wheat rotation system with a large C-sequestration capacity. Monthly average diurnal variations in NEE for different months depicted a U-shaped curve with varying peak values, the maximum peaks appearing at about 12:00 at noon. Seasonal variation in NEE tracked a W-shaped curve in the year for the two crops (winter wheat and summer rice). Maximum daily net CO2 uptake reached 1.12 mg·m2·s-1 in April for wheat and 1.45 mg·m2·s-1 in August for rice. At the same time, daily cumulative C-uptake of wheat and rice reached the maximum values of 12.88 g(C)·m2·d-1 and 10.63 g(C)·m2·d-1, respectively. The rice-wheat rotation system in the Yangtze River Delta was a strong C-sink, with annual carbon fixation of 769.61 g(C)·m2·a-1 for the period 2011–2012. On the whole, the characteristics of NEE were closely related with crop growth and meteorological conditions. The environmental factors influencing NEE at daytime were different from those at nighttime for both winter wheat and summer rice. The main environmental factor impacting NEE was photosynthetically active radiation (PAR) during the daytime and the relationship between PAR and daytime NEE during the two crop growing seasons was well represented by Michaelis-Menten Equation (R2 = 0.370.83). NEE increased with rising temperature and PAR, and decreased when PAR exceeded 1 800 μmol·m2·s-1. Temperature was identified as the main environmental factor influencing NEE at nighttime. There was significant exponential correlation between nighttime NEE and temperature at different levels (air temperature, soil temperatures at 10 cm, 20 cm, and 40 cm depths) in rice-wheat rotation system in the Yangtze River Delta. However, the most related temperature level for nighttime NEE was driven by climatic conditions and crop growth. Correlation analysis of nighttime NEE and temperature suggested that 10 cm depth soil temperature was the most related for winter wheat and air temperature most related for summer rice. To further explore the relationship between temperature and nighttime NEE, there was need for monitoring nighttime fluxes with the combined use of eddy covariance and chamber-based method.
Agro-ecosystem is one of the terrestrial ecosystems under intensive control and human disturbance. The estimation of carbon (C) source or sink in agro-ecosystems is a focal research in global C-cycle studies. As carbon dioxide (CO2) is generally the main greenhouse gas with significant effect on climate change, there has been a growing interest in analyzing and understanding C-flux from agro-ecosystems as affected by regional environmental conditions. To determine diurnal and seasonal variations in net ecosystem exchange (NEE) and to explore the effects of environmental factors, CO2 flux was contAgro-ecosystem is one of the terrestrial ecosystems under intensive control and human disturbance. The estimation of carbon (C) source or sink in agro-ecosystems is a focal research in global C-cycle studies. As carbon dioxide (CO2) is generally the main greenhouse gas with significant effect on climate change, there has been a growing interest in analyzing and understanding C-flux from agro-ecosystems as affected by regional environmental conditions. To determine diurnal and seasonal variations in net ecosystem exchange (NEE) and to explore the effects of environmental factors, CO2 flux was continuously measured in 20112012 using the eddy covariance technique in rice-wheat rotation system in the Yangtze River Delta. During the study, eddy covariance measurement together with measurements of various soil and meteorological conditions were taken for two full growing seasons per year. To derive complete time series of NEE, flux partitioning and gap-filling methods were devised. The results showed significant trends of monthly average diurnal and seasonal variations in NEE in rice-wheat rotation system with a large C-sequestration capacity. Monthly average diurnal variations in NEE for different months depicted a U-shaped curve with varying peak values, the maximum peaks appearing at about 12:00 at noon. Seasonal variation in NEE tracked a W-shaped curve in the year for the two crops (winter wheat and summer rice). Maximum daily net CO2 uptake reached 1.12 mg·m2·s-1 in April for wheat and 1.45 mg·m2·s-1 in August for rice. At the same time, daily cumulative C-uptake of wheat and rice reached the maximum values of 12.88 g(C)·m2·d-1 and 10.63 g(C)·m2·d-1, respectively. The rice-wheat rotation system in the Yangtze River Delta was a strong C-sink, with annual carbon fixation of 769.61 g(C)·m2·a-1 for the period 2011–2012. On the whole, the characteristics of NEE were closely related with crop growth and meteorological conditions. The environmental factors influencing NEE at daytime were different from those at nighttime for both winter wheat and summer rice. The main environmental factor impacting NEE was photosynthetically active radiation (PAR) during the daytime and the relationship between PAR and daytime NEE during the two crop growing seasons was well represented by Michaelis-Menten Equation (R2 = 0.370.83). NEE increased with rising temperature and PAR, and decreased when PAR exceeded 1 800 μmol·m2·s-1. Temperature was identified as the main environmental factor influencing NEE at nighttime. There was significant exponential correlation between nighttime NEE and temperature at different levels (air temperature, soil temperatures at 10 cm, 20 cm, and 40 cm depths) in rice-wheat rotation system in the Yangtze River Delta. However, the most related temperature level for nighttime NEE was driven by climatic conditions and crop growth. Correlation analysis of nighttime NEE and temperature suggested that 10 cm depth soil temperature was the most related for winter wheat and air temperature most related for summer rice. To further explore the relationship between temperature and nighttime NEE, there was need for monitoring nighttime fluxes with the combined use of eddy covariance and chamber-based method.
2015, 23(7): 812-822.
doi: 10.13930/j.cnki.cjea.150125
Abstract:
To control serious agricultural non-point source pollution and improve use efficiency of nitrogen (N) fertilizer in North China, this study investigated nitrogen use efficiency in different planting patterns of paddy fields in a typical rice cultivation zone in Baodi of Tianjin City. With an entire paddy field ecosystem as the basic research unit, N migration and transformation model in paddy field was established based on N input and output. In order to explore N uptake and use efficiency in coTo control serious agricultural non-point source pollution and improve use efficiency of nitrogen (N) fertilizer in North China, this study investigated nitrogen use efficiency in different planting patterns of paddy fields in a typical rice cultivation zone in Baodi of Tianjin City. With an entire paddy field ecosystem as the basic research unit, N migration and transformation model in paddy field was established based on N input and output. In order to explore N uptake and use efficiency in conventional rice field pattern (CK: rice monoculture) and stereoscopic planting rice field pattern (RF: rice-fish-shrimp-crab co-culture + bund + ditch), a field experiment was conducted to analyze the characteristics of N input and N output. The differences in N use efficiency and yield of rice between two paddy planting patterns were investigated too. Results showed that N input of two rice field patterns was mainly from irrigation, fertilization and precipitation. N input from fertilizer in RF system was 128.25 kg(N)·hm-2, 11.75 kg(N)·hm-2 less than that of CK, and was 14%52% less than that of other rice planting regions in South China. In RF system, N input at source was limited, thus reducing the risk of nutrient loss. N output of CK system was composed of soil fixation, ammonia volatilization, N loss via lateral seepage, and crop N uptake. In addition to components of N output of CK, N output of RF system contained N absorptions by fishes, shrimps and crabs. Due to special bund-ditch ecological purification in RF system, N loss through lateral seepage dropped by 9.33 kg(N)·hm-2 and NO3-N was the main form of lateral seepage. N loss via ammonia volatilization in RF and CK systems was 8.91 kg·hm-2 and 21.54 kg·hm-2, respectively. Ammonia volatilization rate in RF system accounted for 6.9% of total amount of applied fertilizer, which was 8.5% less than that in CK and 10.3% less than the national average. Compared with CK, RF system harvested 6.65% higher rice yield. N uptake by rice and aquatic materials was 271.72 kg(N)·hm-2 in RF system, 255.05 kg(N)·hm-2 in CK system. The results suggested that breeding fishes, shrimps and crabs did not reduced rice yield. N use efficiency in RF system reached 64.3%, which was 19.7% higher than that in CK. RF not only achieved high rice yield, but also reduced N loss in paddy fields. Therefore stereoscopic planting rice field was feasible in North China where irrigation demands were well met. This study provided a critical reference for controlling agricultural non-point source pollution in North China.
To control serious agricultural non-point source pollution and improve use efficiency of nitrogen (N) fertilizer in North China, this study investigated nitrogen use efficiency in different planting patterns of paddy fields in a typical rice cultivation zone in Baodi of Tianjin City. With an entire paddy field ecosystem as the basic research unit, N migration and transformation model in paddy field was established based on N input and output. In order to explore N uptake and use efficiency in coTo control serious agricultural non-point source pollution and improve use efficiency of nitrogen (N) fertilizer in North China, this study investigated nitrogen use efficiency in different planting patterns of paddy fields in a typical rice cultivation zone in Baodi of Tianjin City. With an entire paddy field ecosystem as the basic research unit, N migration and transformation model in paddy field was established based on N input and output. In order to explore N uptake and use efficiency in conventional rice field pattern (CK: rice monoculture) and stereoscopic planting rice field pattern (RF: rice-fish-shrimp-crab co-culture + bund + ditch), a field experiment was conducted to analyze the characteristics of N input and N output. The differences in N use efficiency and yield of rice between two paddy planting patterns were investigated too. Results showed that N input of two rice field patterns was mainly from irrigation, fertilization and precipitation. N input from fertilizer in RF system was 128.25 kg(N)·hm-2, 11.75 kg(N)·hm-2 less than that of CK, and was 14%52% less than that of other rice planting regions in South China. In RF system, N input at source was limited, thus reducing the risk of nutrient loss. N output of CK system was composed of soil fixation, ammonia volatilization, N loss via lateral seepage, and crop N uptake. In addition to components of N output of CK, N output of RF system contained N absorptions by fishes, shrimps and crabs. Due to special bund-ditch ecological purification in RF system, N loss through lateral seepage dropped by 9.33 kg(N)·hm-2 and NO3-N was the main form of lateral seepage. N loss via ammonia volatilization in RF and CK systems was 8.91 kg·hm-2 and 21.54 kg·hm-2, respectively. Ammonia volatilization rate in RF system accounted for 6.9% of total amount of applied fertilizer, which was 8.5% less than that in CK and 10.3% less than the national average. Compared with CK, RF system harvested 6.65% higher rice yield. N uptake by rice and aquatic materials was 271.72 kg(N)·hm-2 in RF system, 255.05 kg(N)·hm-2 in CK system. The results suggested that breeding fishes, shrimps and crabs did not reduced rice yield. N use efficiency in RF system reached 64.3%, which was 19.7% higher than that in CK. RF not only achieved high rice yield, but also reduced N loss in paddy fields. Therefore stereoscopic planting rice field was feasible in North China where irrigation demands were well met. This study provided a critical reference for controlling agricultural non-point source pollution in North China.
2015, 23(7): 823-831.
doi: 10.13930/j.cnki.cjea.141358
Abstract:
In Southwest China, one of the most densely populated agricultural regions, intercropping has been practiced in major grain production systems for a long period. Wheat/maize/soybean strip relay intercropping (W/M/S) system is one of the main planting patterns in Sichuan Province. In the system, wheat was sowed in autumn of the last year, maize transplanted around half month before wheat harvest, and soybean sowed after wheat harvest. This system is very important for achieving optimal crop yield, promoting system productivity and simultaneously decreasing phosphorus (P) losses through optimizing soil P management in the system. A three-year field experiment (20112013) was conducted with 5 P application rates [on maize strip: 0 kg·hm-2, 37.5 kg(P2O5)·hm-2, 75 kg(P2O5)hm-2, 112.5 kg(P2O5)·hm2 and 150 kg(P2O5)·hm-2; on wheat strip: 0 kg(P2O5)·hm-2, 45 kg(P2O5)·hm-2, 90 kg(P2O5)·hm-2, 135 kg(P2O5)·hm-2 and 180 kg(P2O5)·hm-2; soybean was not fertilized] to determine the changes in soil Olsen-P, total P, CaCl2-P and annual variability of available P in the cropping system. The results showed that P application rate at 165 kg(P2O5)·hm-2 (75 kg·hm-2 on maize strip and 90 kg·hm-2 on wheat-soybean strip, P2 treatment) met the demand for P in W/M/S system. There was an apparent balance between P input and P output with soil Olsen-P content maintained at 20 mg·kg-1. The linear-plateau model well described the correlation between Olsen-P and crop yield, with the change-point showing that the critical levels of soil Olsen-P for maximum wheat, maize and soybean yields were 12.6 mg·kg-1, 16.5 mg·kg-1 and 8.8 mg·kg-1, respectively. From 2011 to 2013, soil Olsen-P in the top 020 cm soil layer under P0, P1, P2, P3 and P4 treatments (P application rates of the W/M/S system were the total of wheat and maize application rates, respectively) changed by 1.2 mg·kg-1·a-1, 0.9 mg·kg-1·a-1, 0.2 mg·kg-1·a-1, 2.0 mg·kg-1·a-1 and 2.7 mg·kg-1·a-1, respectively, while total P changed by 0.024 g·kg-1·a-1, 0.016 g·kg-1·a-1, 0.016 g·kg-1·a-1, 0.11 g·kg-1·a-1 and 0.15 g·kg-1·a-1, respectively. Soil Olsen-P increased 1.70 mg·kg-1 and 6.49 mg·kg-1 when soil total P was below 0.55 g·kg-1 and above 0.55 g·kg-1, respectively, with increasing soil total P per 0.1 g·kg-1. Soil CaCl2-P increased by 0.017 mg·kg-1 for per 1 mg·kg1 increase in Olsen-P when soil Olsen-P content was lower than 40 mg·kg-1. In short, simultaneously maintaining soil fertility and increasing crop yield or productivity in W/M/S system required keeping soil total P content under 0.55 g·kg1 and holding soil Olsen-P at 20 mg·kg-1.
In Southwest China, one of the most densely populated agricultural regions, intercropping has been practiced in major grain production systems for a long period. Wheat/maize/soybean strip relay intercropping (W/M/S) system is one of the main planting patterns in Sichuan Province. In the system, wheat was sowed in autumn of the last year, maize transplanted around half month before wheat harvest, and soybean sowed after wheat harvest. This system is very important for achieving optimal crop yield, promoting system productivity and simultaneously decreasing phosphorus (P) losses through optimizing soil P management in the system. A three-year field experiment (20112013) was conducted with 5 P application rates [on maize strip: 0 kg·hm-2, 37.5 kg(P2O5)·hm-2, 75 kg(P2O5)hm-2, 112.5 kg(P2O5)·hm2 and 150 kg(P2O5)·hm-2; on wheat strip: 0 kg(P2O5)·hm-2, 45 kg(P2O5)·hm-2, 90 kg(P2O5)·hm-2, 135 kg(P2O5)·hm-2 and 180 kg(P2O5)·hm-2; soybean was not fertilized] to determine the changes in soil Olsen-P, total P, CaCl2-P and annual variability of available P in the cropping system. The results showed that P application rate at 165 kg(P2O5)·hm-2 (75 kg·hm-2 on maize strip and 90 kg·hm-2 on wheat-soybean strip, P2 treatment) met the demand for P in W/M/S system. There was an apparent balance between P input and P output with soil Olsen-P content maintained at 20 mg·kg-1. The linear-plateau model well described the correlation between Olsen-P and crop yield, with the change-point showing that the critical levels of soil Olsen-P for maximum wheat, maize and soybean yields were 12.6 mg·kg-1, 16.5 mg·kg-1 and 8.8 mg·kg-1, respectively. From 2011 to 2013, soil Olsen-P in the top 020 cm soil layer under P0, P1, P2, P3 and P4 treatments (P application rates of the W/M/S system were the total of wheat and maize application rates, respectively) changed by 1.2 mg·kg-1·a-1, 0.9 mg·kg-1·a-1, 0.2 mg·kg-1·a-1, 2.0 mg·kg-1·a-1 and 2.7 mg·kg-1·a-1, respectively, while total P changed by 0.024 g·kg-1·a-1, 0.016 g·kg-1·a-1, 0.016 g·kg-1·a-1, 0.11 g·kg-1·a-1 and 0.15 g·kg-1·a-1, respectively. Soil Olsen-P increased 1.70 mg·kg-1 and 6.49 mg·kg-1 when soil total P was below 0.55 g·kg-1 and above 0.55 g·kg-1, respectively, with increasing soil total P per 0.1 g·kg-1. Soil CaCl2-P increased by 0.017 mg·kg-1 for per 1 mg·kg1 increase in Olsen-P when soil Olsen-P content was lower than 40 mg·kg-1. In short, simultaneously maintaining soil fertility and increasing crop yield or productivity in W/M/S system required keeping soil total P content under 0.55 g·kg1 and holding soil Olsen-P at 20 mg·kg-1.
2015, 23(7): 832-840.
Abstract:
To understand the enhancing effects of nitrogen (N) and phosphorus (P) on drought resistance of Coffea arabica L. at juvenile stage, a pot experiment was conducted at the Division of Xishuangbanna Tropical Botanical Garden, Chinese Academy of Sciences, Kunming, Yunnan Province, China. The experiment consisted of eighteen treatments (in 3 × 3 × 2 design) with three N rates [N0 (0 g·plant-1), N1 (2.5 g·plant-1) and N2 (7.5 g·plant-1)], three P rates [P0 (0 g·plant-1), P1 (2.5 g·plant-1) and P2 (7.5 g·plant-1)] and two water treatments (normal water supply and drought stress). To learn the effects of different fertilizer and water treatments on various coffee traits, we mainly investigated coffee leaf relative water content (LRWC), photosynthetic characteristics, chlorophyll content, morphology and biomass allocation. The results showed that LRWC, maximum net photosynthetic rate (Pn), stomatal conductance (gs), transpiration rate (Tr), chlorophyll content, specific leaf area (SLA) and biomass allocation under drought stress were lower than those under normal water supply. Both N and P slowed down LRWC depression induced by drought stress. The LRWC of C. arabica under fertilizer treatments (both single applications of N1, P1 and P2 and combined applications of N1 with P1 or P2) exceeded 72%, and was significantly higher than that of non-fertilizer treatment (N0P0). Both N and P enhanced photosynthetic characteristics of C. arabica. The maximum Pn and water use efficiency (WUE) of fertilizer treatments (N0P1, N0P2 and N1P2) were significantly higher than those of other treatments. Pn of N0P1, N0P2 and N1P2 fertilizer treatments were 2.09 times, 2.09 times and 2.40 times that of N0P0 (non-fertilizer treatment), while the corresponding WUEs were 1.37 times, 1.46 times and 1.58 times that of N0P0. Compared with N0P0, both gs and Tr of fertilizer treatments increased obviously, but with no significant difference among treatments. N and P increased chlorophyll content of coffee leaves and eased chlorophyll degradation rate caused by drought stress. Moreover, combined application of N and P performed better than single application of N or P. The morphology and biomass allocation of C. arabica were obviously influenced by both N and P. And drought stress promoted the distribution of photosynthetic products to underground system, increasing root mass fraction (RMF) and root-to-shoot ratio (R/S), all fertilizer treatments had higher RMF and R/S under drought stress than under normal water supply. N0P1 and N0P2 had the largest RMF and R/S, followed by N1P2 treatment, and root dry weight of N1P2 under drought stress was bigger than under normal water supply. The findings demonstrated that both N and P fertilization were critical for improving drought-resistance of C. arabica at juvenile stage, and N1P2 was the optimum treatment for C. arabica.
To understand the enhancing effects of nitrogen (N) and phosphorus (P) on drought resistance of Coffea arabica L. at juvenile stage, a pot experiment was conducted at the Division of Xishuangbanna Tropical Botanical Garden, Chinese Academy of Sciences, Kunming, Yunnan Province, China. The experiment consisted of eighteen treatments (in 3 × 3 × 2 design) with three N rates [N0 (0 g·plant-1), N1 (2.5 g·plant-1) and N2 (7.5 g·plant-1)], three P rates [P0 (0 g·plant-1), P1 (2.5 g·plant-1) and P2 (7.5 g·plant-1)] and two water treatments (normal water supply and drought stress). To learn the effects of different fertilizer and water treatments on various coffee traits, we mainly investigated coffee leaf relative water content (LRWC), photosynthetic characteristics, chlorophyll content, morphology and biomass allocation. The results showed that LRWC, maximum net photosynthetic rate (Pn), stomatal conductance (gs), transpiration rate (Tr), chlorophyll content, specific leaf area (SLA) and biomass allocation under drought stress were lower than those under normal water supply. Both N and P slowed down LRWC depression induced by drought stress. The LRWC of C. arabica under fertilizer treatments (both single applications of N1, P1 and P2 and combined applications of N1 with P1 or P2) exceeded 72%, and was significantly higher than that of non-fertilizer treatment (N0P0). Both N and P enhanced photosynthetic characteristics of C. arabica. The maximum Pn and water use efficiency (WUE) of fertilizer treatments (N0P1, N0P2 and N1P2) were significantly higher than those of other treatments. Pn of N0P1, N0P2 and N1P2 fertilizer treatments were 2.09 times, 2.09 times and 2.40 times that of N0P0 (non-fertilizer treatment), while the corresponding WUEs were 1.37 times, 1.46 times and 1.58 times that of N0P0. Compared with N0P0, both gs and Tr of fertilizer treatments increased obviously, but with no significant difference among treatments. N and P increased chlorophyll content of coffee leaves and eased chlorophyll degradation rate caused by drought stress. Moreover, combined application of N and P performed better than single application of N or P. The morphology and biomass allocation of C. arabica were obviously influenced by both N and P. And drought stress promoted the distribution of photosynthetic products to underground system, increasing root mass fraction (RMF) and root-to-shoot ratio (R/S), all fertilizer treatments had higher RMF and R/S under drought stress than under normal water supply. N0P1 and N0P2 had the largest RMF and R/S, followed by N1P2 treatment, and root dry weight of N1P2 under drought stress was bigger than under normal water supply. The findings demonstrated that both N and P fertilization were critical for improving drought-resistance of C. arabica at juvenile stage, and N1P2 was the optimum treatment for C. arabica.
2015, 23(7): 841-850.
doi: 10.13930/j.cnki.cjea.150024
Abstract:
Water is one of the main limiting factors of crop yield in southern Xinjiang. Water not only affects the accumulation of biomass, but also farm operations and crop nitrogen uptake. There have been several studies on the interactions among water, nitrogen and other farm/crop attributes. However, few studies have investigated the accumulation and distribution characteristics of biomass and nitrogen in island cotton under regulated deficit irrigation. Thus a field experiment was conducted to study the effects of regulated deficit irrigation at budding stage on the accumulation and distribution characteristics of biomass and nitrogen, and yield of island cotton. The aim of the study was to show the regularity of nutrient migration in island cotton under regulated deficit irrigation and to provide theoretical basis for efficient utilization of water and nitrogen in order to promote the cultivation of high-yield island cotton. The experiment was set up as a split plot design with two varieties (‘Xinhai24’ and ‘Xinhai35’, sub-area) of cotton and three drip irrigation quotas [severe deficit irrigation (with 0 m3·hm-2 irrigation at budding stage and 2 850 m3·hm-2 irrigation during growth period), mild deficit irrigation (with 900 m3·hm-2 irrigation at budding stage and 3 750 m3·hm-2 irrigation during growth period), and abundant irrigation (with 1 800 m3·hm-2 irrigation at budding stage and 4 650 m3·hm-2 irrigation during growth period). The results showed that maximum aboveground biomass accumulation rate under severe deficit irrigation occurred 3 d and 7 d earlier than under mild deficit irrigation and abundant irrigation, with the maximum accumulation rates lower by 45.1% and 51.0%, respectively. Duration of rapid increase of biomass under different treatments ranked as severe deficit irrigation < mild deficit irrigation < abundant irrigation. Maximum nitrogen accumulation rate under severe deficit irrigation respectively occurred 8 d and 15 d earlier than that under mild deficit irrigation and abundant irrigation. Maximum accumulation rate of nitrogen was highest under mild deficit irrigation, followed by abundant irrigation and then severe deficit irrigation. There were significant difference in proportion of nitrogen distribution in stems and leaves among severe deficit irrigation, mild deficit irrigation and abundant irrigation. However, nitrogen distributions in stems and leaves were similar under mild deficit irrigation and abundant irrigation. Mean bud, flower and boll nitrogen accumulation under mild deficit irrigation was highest after full budding stage. Lint yield under mild deficit irrigation was highest (average of 2 372.9 kg·hm-2), 11.0% higher than that under abundant irrigation and 41.8% higher than that under severe deficit irrigation. Maximum aboveground biomass and maximum nitrogen accumulation rate occurred earlier for ‘Xinhai24’ than for ‘Xinhai35’. As aboveground biomass and nitrogen accumulation rates were larger, lint yield was higher for ‘Xinhai24’ than for ‘Xinhai35’. The results showed a good correlation between the eigenvalues of biomass and nitrogen accumulation of island cotton under mild regulated deficit irrigation (drip irrigation quota of 900 m3·hm-2 at budding stage). Under this irrigation quota, the distribution proportions in various organs of cotton were reasonable and lint yield high. Lint yield of ‘Xinhai24’ was 2 488.2 kg·hm-2 and that of ‘Xinhai24’ was 2 257.6 kg·hm-2. Thus drip irrigation quota of 900 m3·hm-2 at budding stage was recommended as appropriate irrigation scheme for potential high increase of yield of island cotton.
Water is one of the main limiting factors of crop yield in southern Xinjiang. Water not only affects the accumulation of biomass, but also farm operations and crop nitrogen uptake. There have been several studies on the interactions among water, nitrogen and other farm/crop attributes. However, few studies have investigated the accumulation and distribution characteristics of biomass and nitrogen in island cotton under regulated deficit irrigation. Thus a field experiment was conducted to study the effects of regulated deficit irrigation at budding stage on the accumulation and distribution characteristics of biomass and nitrogen, and yield of island cotton. The aim of the study was to show the regularity of nutrient migration in island cotton under regulated deficit irrigation and to provide theoretical basis for efficient utilization of water and nitrogen in order to promote the cultivation of high-yield island cotton. The experiment was set up as a split plot design with two varieties (‘Xinhai24’ and ‘Xinhai35’, sub-area) of cotton and three drip irrigation quotas [severe deficit irrigation (with 0 m3·hm-2 irrigation at budding stage and 2 850 m3·hm-2 irrigation during growth period), mild deficit irrigation (with 900 m3·hm-2 irrigation at budding stage and 3 750 m3·hm-2 irrigation during growth period), and abundant irrigation (with 1 800 m3·hm-2 irrigation at budding stage and 4 650 m3·hm-2 irrigation during growth period). The results showed that maximum aboveground biomass accumulation rate under severe deficit irrigation occurred 3 d and 7 d earlier than under mild deficit irrigation and abundant irrigation, with the maximum accumulation rates lower by 45.1% and 51.0%, respectively. Duration of rapid increase of biomass under different treatments ranked as severe deficit irrigation < mild deficit irrigation < abundant irrigation. Maximum nitrogen accumulation rate under severe deficit irrigation respectively occurred 8 d and 15 d earlier than that under mild deficit irrigation and abundant irrigation. Maximum accumulation rate of nitrogen was highest under mild deficit irrigation, followed by abundant irrigation and then severe deficit irrigation. There were significant difference in proportion of nitrogen distribution in stems and leaves among severe deficit irrigation, mild deficit irrigation and abundant irrigation. However, nitrogen distributions in stems and leaves were similar under mild deficit irrigation and abundant irrigation. Mean bud, flower and boll nitrogen accumulation under mild deficit irrigation was highest after full budding stage. Lint yield under mild deficit irrigation was highest (average of 2 372.9 kg·hm-2), 11.0% higher than that under abundant irrigation and 41.8% higher than that under severe deficit irrigation. Maximum aboveground biomass and maximum nitrogen accumulation rate occurred earlier for ‘Xinhai24’ than for ‘Xinhai35’. As aboveground biomass and nitrogen accumulation rates were larger, lint yield was higher for ‘Xinhai24’ than for ‘Xinhai35’. The results showed a good correlation between the eigenvalues of biomass and nitrogen accumulation of island cotton under mild regulated deficit irrigation (drip irrigation quota of 900 m3·hm-2 at budding stage). Under this irrigation quota, the distribution proportions in various organs of cotton were reasonable and lint yield high. Lint yield of ‘Xinhai24’ was 2 488.2 kg·hm-2 and that of ‘Xinhai24’ was 2 257.6 kg·hm-2. Thus drip irrigation quota of 900 m3·hm-2 at budding stage was recommended as appropriate irrigation scheme for potential high increase of yield of island cotton.
2015, 23(7): 851-859.
doi: 10.13930/j.cnki.cjea.141227
Abstract:
To study the impact of jujube forest on soil moisture in the loess hilly and gully region, a long-term observation of soil moisture in Mizhi County, Shaanxi Province was conducted. Short-term soil moisture with measured soil physical properties, and soil moisture in four types of jujube forests were investigated. The jujube forest types were 5 years and 15 years jujube forests, and 14 years regenerated jujube forest (planted at the same time with the 15 years jujube forest and regenerated in the 14th year). Then the differences in soil moisture in relation to soil texture in different jujube forests were analyzed. The depths of water consumption by jujube trees and the soil desiccation in jujube forests were also studied. The results showed significant difference in soil moisture among different jujube forests. The quantity and depth of water consumption increased with increasing age of jujube tree. This suggested larger water consumption of soil of older jujube trees. Along the soil profile, average soil moistures of 5 years jujube forest and 14 years regenerated jujube forest was not significantly different, but they all significantly different from that of 15 years jujube forest. This suggested that an effective measure of water saving was to timely update jujube forests. Soil moisture was significantly positively related with soil silt particle content, which influenced water uptake by jujube tree roots. The depth of water consumption of jujube forests was 440 cm in 5 years jujube forest, 800 cm in 15 years jujube forest and 840 cm in 14 years regenerated jujube forest. There was apparently severe desiccation in the 400500 cm depth soil layer with 100 cm thick dried soil layer, severe desiccation in the 300600 cm depth soil layer with 300 cm thick dried soil layer in the influence range of jujube tree root water uptake, respectively under 5 years jujube forest and 14 years regenerated jujube forest. Then there were two desiccation layers in the influence sphere of 15 years jujube forest root water uptake, which were severe desiccation in the 200300 cm depth soil layer with 100 cm thick dried soil layer and extreme desiccation in the 300600 cm depth soil layer with 300 cm thick dried soil layer. Compared with other studies, this research increased the depth of soil under jujube forests. Based on earlier research results, we proposed a new method with the soil moisture of wild grassland as reference, to creatively evaluate soil desiccation of jujube forest by using soil relative aridity. Soil moisture condition in jujube forest was related to the age of jujube and soil texture. Regenerated trees following cutting trunks consumed less water. The results provided theoretical basis for sustainable development of jujube forests, soil moisture regulation and dry soil layer control in jujube forestlands in semi-arid mountainous regions. To some extent, this promoted restoration of vegetation in these areas.
To study the impact of jujube forest on soil moisture in the loess hilly and gully region, a long-term observation of soil moisture in Mizhi County, Shaanxi Province was conducted. Short-term soil moisture with measured soil physical properties, and soil moisture in four types of jujube forests were investigated. The jujube forest types were 5 years and 15 years jujube forests, and 14 years regenerated jujube forest (planted at the same time with the 15 years jujube forest and regenerated in the 14th year). Then the differences in soil moisture in relation to soil texture in different jujube forests were analyzed. The depths of water consumption by jujube trees and the soil desiccation in jujube forests were also studied. The results showed significant difference in soil moisture among different jujube forests. The quantity and depth of water consumption increased with increasing age of jujube tree. This suggested larger water consumption of soil of older jujube trees. Along the soil profile, average soil moistures of 5 years jujube forest and 14 years regenerated jujube forest was not significantly different, but they all significantly different from that of 15 years jujube forest. This suggested that an effective measure of water saving was to timely update jujube forests. Soil moisture was significantly positively related with soil silt particle content, which influenced water uptake by jujube tree roots. The depth of water consumption of jujube forests was 440 cm in 5 years jujube forest, 800 cm in 15 years jujube forest and 840 cm in 14 years regenerated jujube forest. There was apparently severe desiccation in the 400500 cm depth soil layer with 100 cm thick dried soil layer, severe desiccation in the 300600 cm depth soil layer with 300 cm thick dried soil layer in the influence range of jujube tree root water uptake, respectively under 5 years jujube forest and 14 years regenerated jujube forest. Then there were two desiccation layers in the influence sphere of 15 years jujube forest root water uptake, which were severe desiccation in the 200300 cm depth soil layer with 100 cm thick dried soil layer and extreme desiccation in the 300600 cm depth soil layer with 300 cm thick dried soil layer. Compared with other studies, this research increased the depth of soil under jujube forests. Based on earlier research results, we proposed a new method with the soil moisture of wild grassland as reference, to creatively evaluate soil desiccation of jujube forest by using soil relative aridity. Soil moisture condition in jujube forest was related to the age of jujube and soil texture. Regenerated trees following cutting trunks consumed less water. The results provided theoretical basis for sustainable development of jujube forests, soil moisture regulation and dry soil layer control in jujube forestlands in semi-arid mountainous regions. To some extent, this promoted restoration of vegetation in these areas.
2015, 23(7): 860-867.
doi: 10.13930/j.cnki.cjea.141364
Abstract:
The study of the spatial and temporal distribution of grazing behavior of sheep can lay the scientific basis for livestock management and rational use of grassland resources. In this paper, the spatial-temporal distribution of fine-wool sheep were determined by attaching GPS collars to the sheep in different vegetation zones under different stocking rates. While the vegetation data were obtained by using satellite data of ALOS in 2010 and Landsat in 2002 and 2010, GIS-based spatial analysis and Ivlev’s electivity index (Ei) of terrain and vegetation coverage of sheep were used to determine the relationship between the temporal and spatial distribution of sheep and the environment. The results showed that sheep walked longer distances for search of feed in summer than in autumn. The distance covered by sheep for search of feed increased with increasing stocking rate. The order of the walking distance of sheep in different stocking rate zones was lightly grazed zones < moderately grazed zones < heavily grazed zones. Terrain was the main environment factor affecting sheep grazing behavior. In the experiment area, though the sheep normally grazed even in slopes with the max gradient (5°~15°), they preferred low gradient terrain. The order of terrain Ei of sheep was flat land > gentle slope > ramp. The difference in Ei of different terrains was smaller in summer than in autumn. Sheep active areas in the morning was different from that in the afternoon. Between 5:308:30 am, sheep were active in northern areas far away from ranch gate, where sheep drunk water. Then from 16:00 to 17:30 pm, sheep were active in southern area near ranch gate. This was related with grazing management — drinking water before and after grazing. Although vegetation coverage had no significant effect on grazing behavior of sheep, sheep avoided grazing in very low vegetation coverage zones with exposed soil surface. Vegetation coverage in desert steppe decreased with increasing stocking rate. Therefore livestock management should take into account different terrains and seasons for different water and grazing management strategies. This can change the spatial and temporal distribution of sheep and reduce the grazing frequency of degraded grasslands.
The study of the spatial and temporal distribution of grazing behavior of sheep can lay the scientific basis for livestock management and rational use of grassland resources. In this paper, the spatial-temporal distribution of fine-wool sheep were determined by attaching GPS collars to the sheep in different vegetation zones under different stocking rates. While the vegetation data were obtained by using satellite data of ALOS in 2010 and Landsat in 2002 and 2010, GIS-based spatial analysis and Ivlev’s electivity index (Ei) of terrain and vegetation coverage of sheep were used to determine the relationship between the temporal and spatial distribution of sheep and the environment. The results showed that sheep walked longer distances for search of feed in summer than in autumn. The distance covered by sheep for search of feed increased with increasing stocking rate. The order of the walking distance of sheep in different stocking rate zones was lightly grazed zones < moderately grazed zones < heavily grazed zones. Terrain was the main environment factor affecting sheep grazing behavior. In the experiment area, though the sheep normally grazed even in slopes with the max gradient (5°~15°), they preferred low gradient terrain. The order of terrain Ei of sheep was flat land > gentle slope > ramp. The difference in Ei of different terrains was smaller in summer than in autumn. Sheep active areas in the morning was different from that in the afternoon. Between 5:308:30 am, sheep were active in northern areas far away from ranch gate, where sheep drunk water. Then from 16:00 to 17:30 pm, sheep were active in southern area near ranch gate. This was related with grazing management — drinking water before and after grazing. Although vegetation coverage had no significant effect on grazing behavior of sheep, sheep avoided grazing in very low vegetation coverage zones with exposed soil surface. Vegetation coverage in desert steppe decreased with increasing stocking rate. Therefore livestock management should take into account different terrains and seasons for different water and grazing management strategies. This can change the spatial and temporal distribution of sheep and reduce the grazing frequency of degraded grasslands.
2015, 23(7): 868-876.
doi: 10.13930/j.cnki.cjea.150018
Abstract:
Leaf area index (LAI) is the main parameter that reflects the status of crop growth. Retrieval of LAI is among the main focuses of quantitative remote sensing in agriculture. Crop spectral information with fine spatial resolution obtained by an Unmanned Aerial Vehicle (UAV) remote sensing monitoring system is used for estimating leaf area, which is important for precision agricultural production and management. In our study, an agricultural UAV remote sensing monitoring system was established based on a multi-rotor UAV with both Canon PowerShot G16 digital camera and ADC-Lite multispectral sensor mounted on the same platform. Based on this system, imageries were acquired over a soybean experimental field in Jiaxiang County of Shandong Province at podding and seed-filling stages. Five vegetation indices [ratio vegetation index (RVI), normalized difference vegetation index (NDVI), soil-adjusted vegetation index (SAVI), difference vegetation index (DVI) and triangle vegetation index (TVI)] were calculated from the data. Together with measured LAI, both the univariate and multivariate empirical models were calibrated for estimating LAI of soybean. The best LAI retrieving models were identified based on best combinations of coefficient of determination (R2), root mean square error (RMSE) and estimated accuracy (EA). It was noted that there was the need to choose the best crop growth period for retrieving LAI. LAI was estimable at higher accuracy at seed-filling than at podding stage. Linear regression model of NDVI most accurately explained retrieval of LAI of soybean, with R2 = 0.829, RMSE = 0.301 and EA = 85.4%. NDVI linear regression model was therefore recommended as the most legible model for estimating LAI of soybean at seed-filling stage in this study area. The model was also recommended for application in mapping the LAI of soybean at seed-filling stage. According to our validation data, LAI map well reflected real-world spatial distribution pattern of LAI in soybean fields. The established agricultural UAV remote sensing monitoring system provided novel insights in guiding precision agriculture applications and the corresponding retrieval models for studying the feasibility of retrieving LAI.
Leaf area index (LAI) is the main parameter that reflects the status of crop growth. Retrieval of LAI is among the main focuses of quantitative remote sensing in agriculture. Crop spectral information with fine spatial resolution obtained by an Unmanned Aerial Vehicle (UAV) remote sensing monitoring system is used for estimating leaf area, which is important for precision agricultural production and management. In our study, an agricultural UAV remote sensing monitoring system was established based on a multi-rotor UAV with both Canon PowerShot G16 digital camera and ADC-Lite multispectral sensor mounted on the same platform. Based on this system, imageries were acquired over a soybean experimental field in Jiaxiang County of Shandong Province at podding and seed-filling stages. Five vegetation indices [ratio vegetation index (RVI), normalized difference vegetation index (NDVI), soil-adjusted vegetation index (SAVI), difference vegetation index (DVI) and triangle vegetation index (TVI)] were calculated from the data. Together with measured LAI, both the univariate and multivariate empirical models were calibrated for estimating LAI of soybean. The best LAI retrieving models were identified based on best combinations of coefficient of determination (R2), root mean square error (RMSE) and estimated accuracy (EA). It was noted that there was the need to choose the best crop growth period for retrieving LAI. LAI was estimable at higher accuracy at seed-filling than at podding stage. Linear regression model of NDVI most accurately explained retrieval of LAI of soybean, with R2 = 0.829, RMSE = 0.301 and EA = 85.4%. NDVI linear regression model was therefore recommended as the most legible model for estimating LAI of soybean at seed-filling stage in this study area. The model was also recommended for application in mapping the LAI of soybean at seed-filling stage. According to our validation data, LAI map well reflected real-world spatial distribution pattern of LAI in soybean fields. The established agricultural UAV remote sensing monitoring system provided novel insights in guiding precision agriculture applications and the corresponding retrieval models for studying the feasibility of retrieving LAI.
2015, 23(7): 877-885.
doi: 10.13930/j.cnki.cjea.141436
Abstract:
To study the effects of conventional and organic farming systems on soil heavy metals contents and heavy metals pollution degree, an experiment was conducted in typical organic and conventional vegetable and wheat fields in five regions of North China (Suning, Quzhou of Hebei Province; Feicheng, Gaotang, and Cao County of Shandong Province). The contents of Cu, Zn, Pb, Cr, Cd and As in 020 cm soils under conventional and organic cropping systems of greenhouse vegetable, open-air vegetable and wheat were measured in the five regions. The pollution degrees of heavy metals under different cropping systems were assessed by using single and comprehensive pollution indexes, geo-accumulation index, and potential ecological hazard coefficient and potential ecological risk index. The results showed that compared with conventional farming, organic farming balanced soil pH, alleviated soil salinization, significantly increased soil organic matter content and cation exchange capacity (CEC) and reduced biological effectiveness of heavy metals in soils in different regions. Also compared with background values, soil contents of heavy metals increased and accumulated to different degrees in five regions. Compared with conventional farming, organic farming effectively reduced contents Cr and Cd in soil. There was obvious enrichment and accumulation of Cu, Zn and As in organic wheat fields because of long-term application of large amounts of organic manure. The use of large quantities of organic manure, chemical fertilizers and pesticides in conventional greenhouse vegetable fields increased the accumulation of Cu, Zn and As in soil than in organic greenhouse vegetation fields. The contents of Cu, As and Zn in open-air organic vegetable fields were not significantly different from those in conventional vegetable fields. The comprehensive pollution index evaluation showed that soils in different investigated regions were lightly polluted and the main contributors were Cd, Cu and Zn. The geo-accumulation index evaluation showed no-pollution to moderate pollution levels in the investigated fields of different regions. Cd is the most obvious pollution heavy metal. Potential ecological hazard index assessment showed a slight potential of ecological risk in the investigated regions and that Cd had a higher ecological risk and showed a slight ecological damage. The research results showed that compared with conventional farming, organic farming comprehensively reduced pollution levels and pollution risks of heavy metals and alleviated ecological hazards of heavy metal in soils in the investigated regions.
To study the effects of conventional and organic farming systems on soil heavy metals contents and heavy metals pollution degree, an experiment was conducted in typical organic and conventional vegetable and wheat fields in five regions of North China (Suning, Quzhou of Hebei Province; Feicheng, Gaotang, and Cao County of Shandong Province). The contents of Cu, Zn, Pb, Cr, Cd and As in 020 cm soils under conventional and organic cropping systems of greenhouse vegetable, open-air vegetable and wheat were measured in the five regions. The pollution degrees of heavy metals under different cropping systems were assessed by using single and comprehensive pollution indexes, geo-accumulation index, and potential ecological hazard coefficient and potential ecological risk index. The results showed that compared with conventional farming, organic farming balanced soil pH, alleviated soil salinization, significantly increased soil organic matter content and cation exchange capacity (CEC) and reduced biological effectiveness of heavy metals in soils in different regions. Also compared with background values, soil contents of heavy metals increased and accumulated to different degrees in five regions. Compared with conventional farming, organic farming effectively reduced contents Cr and Cd in soil. There was obvious enrichment and accumulation of Cu, Zn and As in organic wheat fields because of long-term application of large amounts of organic manure. The use of large quantities of organic manure, chemical fertilizers and pesticides in conventional greenhouse vegetable fields increased the accumulation of Cu, Zn and As in soil than in organic greenhouse vegetation fields. The contents of Cu, As and Zn in open-air organic vegetable fields were not significantly different from those in conventional vegetable fields. The comprehensive pollution index evaluation showed that soils in different investigated regions were lightly polluted and the main contributors were Cd, Cu and Zn. The geo-accumulation index evaluation showed no-pollution to moderate pollution levels in the investigated fields of different regions. Cd is the most obvious pollution heavy metal. Potential ecological hazard index assessment showed a slight potential of ecological risk in the investigated regions and that Cd had a higher ecological risk and showed a slight ecological damage. The research results showed that compared with conventional farming, organic farming comprehensively reduced pollution levels and pollution risks of heavy metals and alleviated ecological hazards of heavy metal in soils in the investigated regions.
2015, 23(7): 886-891.
doi: 10.13930/j.cnki.cjea.141475
Abstract:
Earlier study has focused mainly on the mode of manure treatment of liquid anaerobic fermentation after separation of solid and liquid. Direct anaerobic fermentation of manure is another main mode of current treatment of pig manure in China. Studies on configurations of pig farms and croplands under waste disposal mode of direct anaerobic fermentation of manure are important for reducing pollution from livestock excrement and for promoting sustainable development of animal husbandry. The purpose of this study was to determine optimal farmland area needed for large-scale pig farming so as to provide scientific basis and reference for the establishment of ecological modes for agriculture and animal husbandry. Based on data of proportion of pig population and discharges of nitrogen and phosphorus for different types of swine, rate of nutrient loss during waste treatment and nutrient demands by different crops, the study estimated areas of farmlands matching waste consumption and waste carrying capacities of farmlands with different planting patterns under the typical mode of direct anaerobic fermentation of manure in farm with 10 000 pigs. The results showed that under waste treatment mode of direct anaerobic fermentation of manure, the configuration with 10 000 pig farm needed an farm area of 272.5285.4 hm2 grain/oil crop field, 149.4188.2 hm2 solanaceous vegetable field or 599.41 248.8 hm2 orchard/seedling field for safe disposal of biogas residue and slurry. One hectare of grain/oil crop field, solanaceous vegetable field and orchard/seedlings field were enough for the disposal of biogas residue and slurry produced respectively by 3537 heads, 5367 heads, 817 heads of pig. From the above results, waste treatment patterns and crop types should be rationally determined based on the number of swine bred on a farm and the surrounding farmland area. To ensure the crop nutrient demand was met, there was the need to supplement all crop planting patterns with certain amount of chemical fertilizers after biogas residue and slurry application. Nine patterns of cropping tested in the study needed the application of potassium fertilizer. Among the nine patterns, the potassium supplement for pepper-cucumber pattern was the highest, accounting for 48.0% of potassium demand. Cucumber-tomato pattern was next, accounting for 34.4% of potassium demand. Grain/oil crops and pear and tea fields needed nitrogen 51.2193.7 kg·hm-2 of fertilizer supplement. Solanaceous vegetables, grape and peaches needed 13.8108.8 kg·hm-2 of phosphate fertilizer supplement.
Earlier study has focused mainly on the mode of manure treatment of liquid anaerobic fermentation after separation of solid and liquid. Direct anaerobic fermentation of manure is another main mode of current treatment of pig manure in China. Studies on configurations of pig farms and croplands under waste disposal mode of direct anaerobic fermentation of manure are important for reducing pollution from livestock excrement and for promoting sustainable development of animal husbandry. The purpose of this study was to determine optimal farmland area needed for large-scale pig farming so as to provide scientific basis and reference for the establishment of ecological modes for agriculture and animal husbandry. Based on data of proportion of pig population and discharges of nitrogen and phosphorus for different types of swine, rate of nutrient loss during waste treatment and nutrient demands by different crops, the study estimated areas of farmlands matching waste consumption and waste carrying capacities of farmlands with different planting patterns under the typical mode of direct anaerobic fermentation of manure in farm with 10 000 pigs. The results showed that under waste treatment mode of direct anaerobic fermentation of manure, the configuration with 10 000 pig farm needed an farm area of 272.5285.4 hm2 grain/oil crop field, 149.4188.2 hm2 solanaceous vegetable field or 599.41 248.8 hm2 orchard/seedling field for safe disposal of biogas residue and slurry. One hectare of grain/oil crop field, solanaceous vegetable field and orchard/seedlings field were enough for the disposal of biogas residue and slurry produced respectively by 3537 heads, 5367 heads, 817 heads of pig. From the above results, waste treatment patterns and crop types should be rationally determined based on the number of swine bred on a farm and the surrounding farmland area. To ensure the crop nutrient demand was met, there was the need to supplement all crop planting patterns with certain amount of chemical fertilizers after biogas residue and slurry application. Nine patterns of cropping tested in the study needed the application of potassium fertilizer. Among the nine patterns, the potassium supplement for pepper-cucumber pattern was the highest, accounting for 48.0% of potassium demand. Cucumber-tomato pattern was next, accounting for 34.4% of potassium demand. Grain/oil crops and pear and tea fields needed nitrogen 51.2193.7 kg·hm-2 of fertilizer supplement. Solanaceous vegetables, grape and peaches needed 13.8108.8 kg·hm-2 of phosphate fertilizer supplement.
2015, 23(7): 892-899.
doi: 10.13930/j.cnki.cjea.150212
Abstract:
As a vital biological resource in agricultural production system, crop straws returned into soil are crucial for maintaining and improving soil fertility and crop yield. There are differences in straw decomposition between anaerobic and aerobic conditions. FTIR (Fourier transform infrared spectroscopy) can indicate the dynamic changes in organic components during decomposing process of straws. In this study, the net-bag method was used to determine the decomposition dynamic of rapeseed straw and the characteristics of FTIR under anaerobic and aerobic conditions. The results showed a rapid decomposition rate of rapeseed straw at the start of the decomposing process, and then a slow rate with time. Within 360 days of decomposition, the rates of decomposition of rapeseed straw under anaerobic and aerobic conditions were respectively 60.50% and 68.20%, with corresponding decomposition rate constants (k) of 0.004d-1 and 0.010d-1, and rapeseed straw mass decomposition half-lives (t 1/2) of 229 days and 117 days. Carbon (C) releasing rates of rapeseed straw under anaerobic and aerobic conditions were 70.33% and 77.43%, respectively. Also C releasing rate constant (k) under anaerobic condition (0.025d-1) was smaller than that under aerobic condition (0.026d-1). Then nitrogen (N) releasing rates of rapeseed straw under anaerobic and aerobic conditions were 82.20% and 87.48%, respectively. Also N residues under anaerobic condition was 38.25% higher than that under aerobic condition (P < 0.05) within 360 days decomposition, with the highest difference during the 6090 day incubation period. Infrared spectrum analysis showed that absorption intensities at 3 4303 410 cm1 (stretched hydroxyl), 2 930 cm-1 (stretched methylene) bands significantly decreased. This suggested that the decomposition of organic matter such as carbohydrate and aliphatic compounds decreased. Absorption intensities at 1 4191 425 cm-1 and 1 740 cm-1 (assigned to C=O stretching as well as C—O stretching and C—H deformation of carboxylic acid functional groups) weakened. This suggested that carboxylic acid lipid compounds and lignin contents decreased and that there was higher absorption intensity under anaerobic condition than aerobic condition. Silicon released from rapeseed straw accumulated as oxides such as SiO2. During the process of straw decomposition, aliphatic compounds declined while aromatic compounds increased. Also aerobic condition was beneficial to the decomposition of straw cellulose and hemicellulose, largely supplementing soil C and N.
As a vital biological resource in agricultural production system, crop straws returned into soil are crucial for maintaining and improving soil fertility and crop yield. There are differences in straw decomposition between anaerobic and aerobic conditions. FTIR (Fourier transform infrared spectroscopy) can indicate the dynamic changes in organic components during decomposing process of straws. In this study, the net-bag method was used to determine the decomposition dynamic of rapeseed straw and the characteristics of FTIR under anaerobic and aerobic conditions. The results showed a rapid decomposition rate of rapeseed straw at the start of the decomposing process, and then a slow rate with time. Within 360 days of decomposition, the rates of decomposition of rapeseed straw under anaerobic and aerobic conditions were respectively 60.50% and 68.20%, with corresponding decomposition rate constants (k) of 0.004d-1 and 0.010d-1, and rapeseed straw mass decomposition half-lives (t 1/2) of 229 days and 117 days. Carbon (C) releasing rates of rapeseed straw under anaerobic and aerobic conditions were 70.33% and 77.43%, respectively. Also C releasing rate constant (k) under anaerobic condition (0.025d-1) was smaller than that under aerobic condition (0.026d-1). Then nitrogen (N) releasing rates of rapeseed straw under anaerobic and aerobic conditions were 82.20% and 87.48%, respectively. Also N residues under anaerobic condition was 38.25% higher than that under aerobic condition (P < 0.05) within 360 days decomposition, with the highest difference during the 6090 day incubation period. Infrared spectrum analysis showed that absorption intensities at 3 4303 410 cm1 (stretched hydroxyl), 2 930 cm-1 (stretched methylene) bands significantly decreased. This suggested that the decomposition of organic matter such as carbohydrate and aliphatic compounds decreased. Absorption intensities at 1 4191 425 cm-1 and 1 740 cm-1 (assigned to C=O stretching as well as C—O stretching and C—H deformation of carboxylic acid functional groups) weakened. This suggested that carboxylic acid lipid compounds and lignin contents decreased and that there was higher absorption intensity under anaerobic condition than aerobic condition. Silicon released from rapeseed straw accumulated as oxides such as SiO2. During the process of straw decomposition, aliphatic compounds declined while aromatic compounds increased. Also aerobic condition was beneficial to the decomposition of straw cellulose and hemicellulose, largely supplementing soil C and N.
2015, 23(7): 900-905.
doi: 10.13930/j.cnki.cjea.141352
Abstract:
Cucumber (Cucumis sativus L.) is a major vegetable grown in greenhouses with increasingly severe occurrence and damage of root-knot nematode due to continuous cropping. As there currently is no resistant cucumber variety to root-knot nematode, grafting has been the most effective way of improving the resistance of cucumber to root-knot nematode. However, the huge differences in root-knot nematode resistance among different varieties of cucumber stocks have posed significant challenges to grafting cucumber. To clarify the mechanism of the tolerance of grafted cucumber to root-knot nematode, two stocks with different resistances to root-knot nematode [‘Figleaf gourd’ (low sensitive) and ‘Tianzhen’ (high sensitive)] and cucumber variety ‘Xintaimici’ were used to investigate the effects on Meloidogyne incognita growth and propagation by artificial inoculation. The study also determined the relationship between root exudates of stocks and the hatchability of M. incognit eggs. The results showed that at the start of M. incognita infection, the number of second-instars larvae of root-not nematode in the three varieties roots were significantly different, lowest in ‘Figleaf gourd’ and highest in ‘Xintaimici’. Although all the second-instars larvae in roots developed normally into adults, the total number of nematodes was highest in ‘Xintaimici’ and lowest in ‘Figleaf gourd’. The number of second-instars larvae was also highest in rhizosphere of ‘Xintaimici’ and lowest in ‘Figleaf gourd’. The characteristics and number of eggs in rhizosphere were the same as the second-instars larvae before secondary infection. Root exudates from cucumber and stocks had significant effects on the hatchability of M. incognita eggs, with ‘Xintaimici’ with the highest egg hatching rate followed by ‘Tianzhen’ and ‘Figleaf gourd’. The rates of egg hatching affected by root exudates of the three varieties obviously increased after inoculation with M. incognita, with ‘Xintaimici’ as the highest and ‘Figleaf gourd’ the lowest. Along with growth of cucumber, the enhancement effect of root exudates on egg hatching increased gradually. Based on the above results, root exudates of low susceptible cucumber stocks obviously inhibited M. incognita egg hatching and reduced M. incognita growth and propagation in both roots and rhizospheres. This was a possible mechanism of resistance of grafted cucumber to M. incognita.
Cucumber (Cucumis sativus L.) is a major vegetable grown in greenhouses with increasingly severe occurrence and damage of root-knot nematode due to continuous cropping. As there currently is no resistant cucumber variety to root-knot nematode, grafting has been the most effective way of improving the resistance of cucumber to root-knot nematode. However, the huge differences in root-knot nematode resistance among different varieties of cucumber stocks have posed significant challenges to grafting cucumber. To clarify the mechanism of the tolerance of grafted cucumber to root-knot nematode, two stocks with different resistances to root-knot nematode [‘Figleaf gourd’ (low sensitive) and ‘Tianzhen’ (high sensitive)] and cucumber variety ‘Xintaimici’ were used to investigate the effects on Meloidogyne incognita growth and propagation by artificial inoculation. The study also determined the relationship between root exudates of stocks and the hatchability of M. incognit eggs. The results showed that at the start of M. incognita infection, the number of second-instars larvae of root-not nematode in the three varieties roots were significantly different, lowest in ‘Figleaf gourd’ and highest in ‘Xintaimici’. Although all the second-instars larvae in roots developed normally into adults, the total number of nematodes was highest in ‘Xintaimici’ and lowest in ‘Figleaf gourd’. The number of second-instars larvae was also highest in rhizosphere of ‘Xintaimici’ and lowest in ‘Figleaf gourd’. The characteristics and number of eggs in rhizosphere were the same as the second-instars larvae before secondary infection. Root exudates from cucumber and stocks had significant effects on the hatchability of M. incognita eggs, with ‘Xintaimici’ with the highest egg hatching rate followed by ‘Tianzhen’ and ‘Figleaf gourd’. The rates of egg hatching affected by root exudates of the three varieties obviously increased after inoculation with M. incognita, with ‘Xintaimici’ as the highest and ‘Figleaf gourd’ the lowest. Along with growth of cucumber, the enhancement effect of root exudates on egg hatching increased gradually. Based on the above results, root exudates of low susceptible cucumber stocks obviously inhibited M. incognita egg hatching and reduced M. incognita growth and propagation in both roots and rhizospheres. This was a possible mechanism of resistance of grafted cucumber to M. incognita.
2015, 23(7): 906-913.
doi: 10.13930/j.cnki.cjea.150066
Abstract:
The overuse of chemical pesticides not only kills insect pests and natural enemies, but also affects the spatial relationship between insect pests and their natural enemies. Hylyphantes graminicola is a key predator of Myzus persicae in peach orchard eosystems. In this paper, we systematically investigated M. persicae and its predator H. graminicola populations in peach orchards under chemical pesticide stress at different times (from mid April to early September), used geostatistics and geographic information system (GIS) to analyze the spatial structure, and used ordinary Kriging interpretation with Gaussian, Exponential, Spherical and Circular models to simulate the spatial distribution of the two species.The aim of the study was to understand the spacial distribution of M. persicae and its predator H. graminicola under long-term applicaiton of chemical pestcides and provide the theoretical support for ecological control of peach garden pests. The results suggested that both H. graminicola and M. persicae had random spatial arrangement within 10 iterative times of investigations. The proportions of spatical sturcture [C0/(C+ C0)] of populations of H. graminicola and M. persicae were 0.788 80.983 9 and 0.811 60.980 6 indicating weak spacial relathship bewteen two populaitons under long-term chemical pestcide stress. The nugget values and partial sills of H. Graminicola, M. persicae were respectivel 0.254 2 4.896 3, 0.218 40.749 9 and 0.010 50.250 0, 0.004 80.075 7, respectively, indicating random spatial arrangement, too. The correlation of spatial distribution distance of two species was relatively weak, the distance ranges for the two species was 6.863 0 43.174 1 m. Though the model parameters of semivariograms for M. persicae and H. graminicola at different times were changed greatly due to population density, temperature, and peach growth, the spatial patterns of the two populations were random under long-term chemical pesticide stress. Our study demonstrated that under long-term and excessive use of chemical pesticides in peach orchards, the proportions of H. graminicola and M. persicae spatial structure was greater than 0.750 0, and their spatical patterns were random. This suggested that there was no obvious effect of H. graminicola on M. persicae and that H. graminicola had minimal predatory effect on M. persicae.
The overuse of chemical pesticides not only kills insect pests and natural enemies, but also affects the spatial relationship between insect pests and their natural enemies. Hylyphantes graminicola is a key predator of Myzus persicae in peach orchard eosystems. In this paper, we systematically investigated M. persicae and its predator H. graminicola populations in peach orchards under chemical pesticide stress at different times (from mid April to early September), used geostatistics and geographic information system (GIS) to analyze the spatial structure, and used ordinary Kriging interpretation with Gaussian, Exponential, Spherical and Circular models to simulate the spatial distribution of the two species.The aim of the study was to understand the spacial distribution of M. persicae and its predator H. graminicola under long-term applicaiton of chemical pestcides and provide the theoretical support for ecological control of peach garden pests. The results suggested that both H. graminicola and M. persicae had random spatial arrangement within 10 iterative times of investigations. The proportions of spatical sturcture [C0/(C+ C0)] of populations of H. graminicola and M. persicae were 0.788 80.983 9 and 0.811 60.980 6 indicating weak spacial relathship bewteen two populaitons under long-term chemical pestcide stress. The nugget values and partial sills of H. Graminicola, M. persicae were respectivel 0.254 2 4.896 3, 0.218 40.749 9 and 0.010 50.250 0, 0.004 80.075 7, respectively, indicating random spatial arrangement, too. The correlation of spatial distribution distance of two species was relatively weak, the distance ranges for the two species was 6.863 0 43.174 1 m. Though the model parameters of semivariograms for M. persicae and H. graminicola at different times were changed greatly due to population density, temperature, and peach growth, the spatial patterns of the two populations were random under long-term chemical pesticide stress. Our study demonstrated that under long-term and excessive use of chemical pesticides in peach orchards, the proportions of H. graminicola and M. persicae spatial structure was greater than 0.750 0, and their spatical patterns were random. This suggested that there was no obvious effect of H. graminicola on M. persicae and that H. graminicola had minimal predatory effect on M. persicae.
2015, 23(7): 914-918.
doi: 10.13930/j.cnki.cjea.141502
Abstract:
Pea aphid [Acyrthosiphon pisum (Harris)] at different growth stages were used to explore the host stage preference of Aphidius ervi Haliday to pea aphid and the effect of host-stage parasitism on parasitoid offspring fitness at (24±1) ℃. The results suggested that the host stage of pea aphid had a significant (P < 0.05) influence on the parasitic behavior and fitness of A. ervi offspring. Although A. ervi parasitized on all the stages of pea aphid, the parasitic rate of A. ervi in the 2nd instar aphids was highest (56.67%). This was followed by the parasitic rate in the 1st instar aphids (30.67%) and the 4th instar nymphs, while that in the adults was least. The eclosion rate of offspring of A. ervi was significantly higher in young nymphs than in older hosts. The duration of offspring wasp was longest in the 1st instar aphids. The duration from egg release to mummy appearance of A. ervi in the 1st instar aphids was 9.47 d and that from mummy appearance to eclosion was 5.51 d, which gradually shortened with increasing host stage. The duration of offspring development was longest in the 1st instar aphids (14.85 d) and shortest in adults (7.87 d). The proportion of female offspring of A. ervi was significantly greater in adults (57.33%) than in 1st instar (24.52%). Meanwhile, emerging adult size of offspring increased with increasing host stage (or body size). Host stage (or body size) was positively correlated with parasitoid offspring fitness. From offspring fitness measures, A. ervi females preferred to parasitize in older aphids for higher fitness return despite the risk of lower parasitic rate trade-off. The results suggested that host stage (or body size) significantly influenced parasitic selection of A. ervi and offspring fitness.
Pea aphid [Acyrthosiphon pisum (Harris)] at different growth stages were used to explore the host stage preference of Aphidius ervi Haliday to pea aphid and the effect of host-stage parasitism on parasitoid offspring fitness at (24±1) ℃. The results suggested that the host stage of pea aphid had a significant (P < 0.05) influence on the parasitic behavior and fitness of A. ervi offspring. Although A. ervi parasitized on all the stages of pea aphid, the parasitic rate of A. ervi in the 2nd instar aphids was highest (56.67%). This was followed by the parasitic rate in the 1st instar aphids (30.67%) and the 4th instar nymphs, while that in the adults was least. The eclosion rate of offspring of A. ervi was significantly higher in young nymphs than in older hosts. The duration of offspring wasp was longest in the 1st instar aphids. The duration from egg release to mummy appearance of A. ervi in the 1st instar aphids was 9.47 d and that from mummy appearance to eclosion was 5.51 d, which gradually shortened with increasing host stage. The duration of offspring development was longest in the 1st instar aphids (14.85 d) and shortest in adults (7.87 d). The proportion of female offspring of A. ervi was significantly greater in adults (57.33%) than in 1st instar (24.52%). Meanwhile, emerging adult size of offspring increased with increasing host stage (or body size). Host stage (or body size) was positively correlated with parasitoid offspring fitness. From offspring fitness measures, A. ervi females preferred to parasitize in older aphids for higher fitness return despite the risk of lower parasitic rate trade-off. The results suggested that host stage (or body size) significantly influenced parasitic selection of A. ervi and offspring fitness.
2015, 23(7): 919-930.
doi: 10.13930/j.cnki.cjea.141452
Abstract:
This paper analyzed climate change and the responses of cotton growth period and yield to warming climate since 1961 in Kashgar, Xinjiang Uygur Autonomous Region, China. The paper used the methods of tendency, detection and trend coefficient to determine the rate of climate changes of average temperature, maximum temperature, minimum temperature, precipitation and sunshine duration for the period 19612013. The study also analyzed cotton growth period, yield amount, and characteristics of pre-summer boll, summer boll and autumn boll for the past 23 years (19902013) of ground-truth data in the national reference stations of Kashgar (75°59′E, 39°28′N). The results showed that average annual temperature, average seasonal temperature, average maximum and average minimum temperature increased significantly in the past 53 years (19612013). The rates of warming in annual temperature, spring temperature, summer temperature and autumn temperature were respectively 0.250.47 ℃10a-1 (P< 0.01), 0.240.47 ℃10a-1 (P< 0.05), 0.090.37 ℃10a-1 and 0.320.46 ℃10a-1 (P< 0.01). Among the variables, the trends of increase in average minimum temperature in spring and autumn were of significant. Yearly precipitation apparently increased at a rate of 6.16 mm10a1. Spring precipitation declined at a rate of 0.44 mm10a1, while summer and autumn precipitations increased at rates of 2.10 mm10a-1 and 2.23 mm10a-1(P < 0.05), respectively. There was significant positive trend in sunshine duration, increasing at a rate of 31.3 h10a-1 (P< 0.05) at annua-1 scale, 16.16 h10a-1 (P< 0.01) during spring, 9.84 h10a-1 (P< 0.05) during summer and 4.27 h10a-1(P< 0.01) during autumn. The highest increase was in spring. The date of the latest frost advanced (1.3 d10a-1), the date of the first frost delayed (1.4 d10a-1) and then frost-free period lengthened (1.0 d10a-1) in the past 53 years from 1961 to 2013. Over the past 23 years (19902013), average sowing date, seedling stage, third true leaf stage, fifth true leaf stage, squaring stage, flowering stage, cracked-bell stage and boll-opening stage of cotton apparently advanced to different degrees, with the trend in squaring stage as most obvious — 6.6 d10a-1 (P< 0.01). Cotton sub-stop growth season date delayed by about 4.2 d10a-1 (P< 0.01), the extended growth period was very favorable for cotton yield and quality. The numbers of pre- summer boll, summer boll and autumn boll of cotton significantly increased at respective rates of 0.58 bolls10a1, 0.92 bolls10a1 and 0.49 bolls1 a-1. Average yield per acre increased in the past 23 years (19902013) by 373.5 kghm210a-1 (P< 0.01). The factors influencing cotton growth period and yield were temperature, precipitation and sunshine duration which changed frost days, last frost day and frost-free period, suggesting that warming climate very much favored cotton production and quality in Kashgar region. This study suggested that cotton yield was positively correlated with last frost date, first frost date and frost-free period. Last frost date apparently advanced, first frost date apparently delayed, and frost-free period lengthened, enhancing cotton production in the study area.
This paper analyzed climate change and the responses of cotton growth period and yield to warming climate since 1961 in Kashgar, Xinjiang Uygur Autonomous Region, China. The paper used the methods of tendency, detection and trend coefficient to determine the rate of climate changes of average temperature, maximum temperature, minimum temperature, precipitation and sunshine duration for the period 19612013. The study also analyzed cotton growth period, yield amount, and characteristics of pre-summer boll, summer boll and autumn boll for the past 23 years (19902013) of ground-truth data in the national reference stations of Kashgar (75°59′E, 39°28′N). The results showed that average annual temperature, average seasonal temperature, average maximum and average minimum temperature increased significantly in the past 53 years (19612013). The rates of warming in annual temperature, spring temperature, summer temperature and autumn temperature were respectively 0.250.47 ℃10a-1 (P< 0.01), 0.240.47 ℃10a-1 (P< 0.05), 0.090.37 ℃10a-1 and 0.320.46 ℃10a-1 (P< 0.01). Among the variables, the trends of increase in average minimum temperature in spring and autumn were of significant. Yearly precipitation apparently increased at a rate of 6.16 mm10a1. Spring precipitation declined at a rate of 0.44 mm10a1, while summer and autumn precipitations increased at rates of 2.10 mm10a-1 and 2.23 mm10a-1(P < 0.05), respectively. There was significant positive trend in sunshine duration, increasing at a rate of 31.3 h10a-1 (P< 0.05) at annua-1 scale, 16.16 h10a-1 (P< 0.01) during spring, 9.84 h10a-1 (P< 0.05) during summer and 4.27 h10a-1(P< 0.01) during autumn. The highest increase was in spring. The date of the latest frost advanced (1.3 d10a-1), the date of the first frost delayed (1.4 d10a-1) and then frost-free period lengthened (1.0 d10a-1) in the past 53 years from 1961 to 2013. Over the past 23 years (19902013), average sowing date, seedling stage, third true leaf stage, fifth true leaf stage, squaring stage, flowering stage, cracked-bell stage and boll-opening stage of cotton apparently advanced to different degrees, with the trend in squaring stage as most obvious — 6.6 d10a-1 (P< 0.01). Cotton sub-stop growth season date delayed by about 4.2 d10a-1 (P< 0.01), the extended growth period was very favorable for cotton yield and quality. The numbers of pre- summer boll, summer boll and autumn boll of cotton significantly increased at respective rates of 0.58 bolls10a1, 0.92 bolls10a1 and 0.49 bolls1 a-1. Average yield per acre increased in the past 23 years (19902013) by 373.5 kghm210a-1 (P< 0.01). The factors influencing cotton growth period and yield were temperature, precipitation and sunshine duration which changed frost days, last frost day and frost-free period, suggesting that warming climate very much favored cotton production and quality in Kashgar region. This study suggested that cotton yield was positively correlated with last frost date, first frost date and frost-free period. Last frost date apparently advanced, first frost date apparently delayed, and frost-free period lengthened, enhancing cotton production in the study area.
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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