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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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2013 Vol. 21, No. 10
Display Method:
2013, 21(10): 1173-1183.
doi: 10.3724/SP.J.1011.2013.30870
Abstract:
Since allelopathy was defined by Rice in 1984, important research progress has been made on the plant allelopathy. Previous studies demonstrated that plant allelopathy has four types (or action modes), amensalism, autotoxicity, stimulation and facilitation. Plant allelopathy was widely understood as the harmful effects (amensalism) of one plant on another plant due to chemicals that were released into the environment, especially into the soil environment. Increasing studies showed that plant allelopathy was the result of the comprehensive effect of plant-microbe interactions mediated by root exudates. Amensalism has been applied in weeds control, and great achievements have been made in the practice. Allelopathic autotoxicity, also known as consecutive monoculture problems, was shown as serious soil disease in plants, consequently resulting in decreased biomass and quality of plant under consecutive monoculture. The allelopathic autotoxicity of medical herbs, especially those with tuberous roots for medicinal use, was just the case with much more sensitive reaction. Recent researches has displayed that the ecological effects of soil microbial functional disorder mediated by root exudates were the main reasons for the consecutive monoculture problems. The findings suggested that the improvement of disease-conducive soil environment was crucial to the remediation of unbalanced microbial community consturcture, and increase of ecosystem functions to overcome the problems. Positive allelopathic stimulation referred to that the monocultured plants graw well, showing higher biomass and better quality with the increasing years of consecutive cropping. Although the mechanism for positive allelopathic stimulation was not deeply understood, it suggested that the ecological phenomena mainly resulted from the improvement of soil microbial community constructure and their interaction mediated by root exudates, including positive and negative facilitation among microorganisms in rhizosphere soil, and hence increased soil fertility and nutrient supply ability, thereby, enforced root resistance to disease, consequently resulted in enhanced plant yield and quality. Achyranthes bidentata Blume was found to be a typical medicinal plant with positive allelopatic effects after continuously monocultured, and had been used as a rotation/intercropping crop with other medicinal plants sensitive to consecutive cropping to keep sustainable production of medicinal herbs. Positive interspecific interactions (facilitation) including commensalism, mutualism and protocooperation, have become a hotspot at home and abroad. Many scholars found that the mutually beneficial relationships in rhizosphere between plant species, especially the plant-microbe interactions mediated by root exudates, played important roles in the yield increase of intercropping system and efficient utilization of soil nutrients. Finally, the authors emphasized that the compositon of metagenome of the complex plant-associated microbial community existing in rhizosphere was the key to the crop plants whether they can healthily grow in the monoculture system. More in-depth studies in the second genome and oriented control of rhizospheric biological processes based on the principle and technology of modern synthetic biology would become the priority research areas to promote the sustainable development of agricultural production.
Since allelopathy was defined by Rice in 1984, important research progress has been made on the plant allelopathy. Previous studies demonstrated that plant allelopathy has four types (or action modes), amensalism, autotoxicity, stimulation and facilitation. Plant allelopathy was widely understood as the harmful effects (amensalism) of one plant on another plant due to chemicals that were released into the environment, especially into the soil environment. Increasing studies showed that plant allelopathy was the result of the comprehensive effect of plant-microbe interactions mediated by root exudates. Amensalism has been applied in weeds control, and great achievements have been made in the practice. Allelopathic autotoxicity, also known as consecutive monoculture problems, was shown as serious soil disease in plants, consequently resulting in decreased biomass and quality of plant under consecutive monoculture. The allelopathic autotoxicity of medical herbs, especially those with tuberous roots for medicinal use, was just the case with much more sensitive reaction. Recent researches has displayed that the ecological effects of soil microbial functional disorder mediated by root exudates were the main reasons for the consecutive monoculture problems. The findings suggested that the improvement of disease-conducive soil environment was crucial to the remediation of unbalanced microbial community consturcture, and increase of ecosystem functions to overcome the problems. Positive allelopathic stimulation referred to that the monocultured plants graw well, showing higher biomass and better quality with the increasing years of consecutive cropping. Although the mechanism for positive allelopathic stimulation was not deeply understood, it suggested that the ecological phenomena mainly resulted from the improvement of soil microbial community constructure and their interaction mediated by root exudates, including positive and negative facilitation among microorganisms in rhizosphere soil, and hence increased soil fertility and nutrient supply ability, thereby, enforced root resistance to disease, consequently resulted in enhanced plant yield and quality. Achyranthes bidentata Blume was found to be a typical medicinal plant with positive allelopatic effects after continuously monocultured, and had been used as a rotation/intercropping crop with other medicinal plants sensitive to consecutive cropping to keep sustainable production of medicinal herbs. Positive interspecific interactions (facilitation) including commensalism, mutualism and protocooperation, have become a hotspot at home and abroad. Many scholars found that the mutually beneficial relationships in rhizosphere between plant species, especially the plant-microbe interactions mediated by root exudates, played important roles in the yield increase of intercropping system and efficient utilization of soil nutrients. Finally, the authors emphasized that the compositon of metagenome of the complex plant-associated microbial community existing in rhizosphere was the key to the crop plants whether they can healthily grow in the monoculture system. More in-depth studies in the second genome and oriented control of rhizospheric biological processes based on the principle and technology of modern synthetic biology would become the priority research areas to promote the sustainable development of agricultural production.
2013, 21(10): 1184-1192.
doi: 10.3724/SP.J.1011.2013.30248
Abstract:
Maize (Zea mays L.) is one of the three staple food crops in China. Synthetic nitrogen fertilizer (SNF) significantly contributes to maize yield. Nevertheless, SNF could also cause problems such as environmental pollution and resource waste. SNF use efficiency of maize in China has become a significant concern in maize production. The negative consequences of SNF have been far more serious in China in recent years due to unscientific applications, including excessive use and outdated management practices. Based on climatic conditions and crop management systems, maize production area in China has been divided into six cropping regions. These included the northern spring maize region, Huang-Huai-Hai Plain spring and summer maize region, southwest mountain maize region, southern hilly maize region, northwest irrigated maize region and Qinghai-Tibet Plateau maize region. Nitrogen use efficiency in the different regions varied greatly based on local production conditions. The objective of this study was to outline the spatial and temporal distribution patterns of nitrogen use efficiency via calculations of SNF application rate (AR), recovery efficiency (RE), agronomic efficiency (AE) and partial factor productivity (PFP) of maize in the different ecological regions of China for the last decades using the up-scaling average method. The results showed that national average AR increased gradually from 93.3 kg·hm-2 in the 1970s to 238.2 kg·hm-2 in the 2010s at the rate of 50.0 kg·hm-2 per decade. The national average of RE and AE decreased from 42.1% and 17.0 kg·kg-1 in the 1970s to 26.4% and 9.5 kg·kg-1 in the 2010s, respectively. Also while the national average of RE decreased rapidly during 1990s, that of AE decreased sharply during 2000s. Unlike RE and AE, the national average PFP remained relatively stable, falling to a narrow range of 40 45 kg·kg-1. The variations in AR and nitrogen use efficiency were a little more intricate in the different regions. Northern spring maize region showed a relatively less increase in AR compared with the other regions. Thus AR rate in this region remained within a reasonable range, only 217.8 kg·hm-2 even in 2000s. Nitrogen use efficiency in the region was relatively higher, and RE and AE reached 46.4% in the 1970s and 43.8% in the 1980s before decreasing rapidly to 33.5% in 1990s and 28.6% in 2000s; higher than the national average for all the periods. The southwest mountain maize region displayed a similar trend, relatively lower AR and higher nitrogen use efficiency than the northern spring maize region. The Huang-Huai-Hai Plain spring and summer maize region was increasingly crucial for Chinese maize production. Both RE and AE in the Huang-Huai-Hai Plain spring and summer maize region were lower than the national average due to excessive fertilizer application. This was especially obvious during 2000s when RE and AE in the region were only 23.5% and 6.7 kg·kg-1 respectively, both much lower than other regions. Moreover, balanced fertilizer application, high-efficiency nitrogen genotype and improved agricultural management were main alternatives to enhancing SNF use efficiency, reducing resources waste and alleviating environmental pollution in China.
Maize (Zea mays L.) is one of the three staple food crops in China. Synthetic nitrogen fertilizer (SNF) significantly contributes to maize yield. Nevertheless, SNF could also cause problems such as environmental pollution and resource waste. SNF use efficiency of maize in China has become a significant concern in maize production. The negative consequences of SNF have been far more serious in China in recent years due to unscientific applications, including excessive use and outdated management practices. Based on climatic conditions and crop management systems, maize production area in China has been divided into six cropping regions. These included the northern spring maize region, Huang-Huai-Hai Plain spring and summer maize region, southwest mountain maize region, southern hilly maize region, northwest irrigated maize region and Qinghai-Tibet Plateau maize region. Nitrogen use efficiency in the different regions varied greatly based on local production conditions. The objective of this study was to outline the spatial and temporal distribution patterns of nitrogen use efficiency via calculations of SNF application rate (AR), recovery efficiency (RE), agronomic efficiency (AE) and partial factor productivity (PFP) of maize in the different ecological regions of China for the last decades using the up-scaling average method. The results showed that national average AR increased gradually from 93.3 kg·hm-2 in the 1970s to 238.2 kg·hm-2 in the 2010s at the rate of 50.0 kg·hm-2 per decade. The national average of RE and AE decreased from 42.1% and 17.0 kg·kg-1 in the 1970s to 26.4% and 9.5 kg·kg-1 in the 2010s, respectively. Also while the national average of RE decreased rapidly during 1990s, that of AE decreased sharply during 2000s. Unlike RE and AE, the national average PFP remained relatively stable, falling to a narrow range of 40 45 kg·kg-1. The variations in AR and nitrogen use efficiency were a little more intricate in the different regions. Northern spring maize region showed a relatively less increase in AR compared with the other regions. Thus AR rate in this region remained within a reasonable range, only 217.8 kg·hm-2 even in 2000s. Nitrogen use efficiency in the region was relatively higher, and RE and AE reached 46.4% in the 1970s and 43.8% in the 1980s before decreasing rapidly to 33.5% in 1990s and 28.6% in 2000s; higher than the national average for all the periods. The southwest mountain maize region displayed a similar trend, relatively lower AR and higher nitrogen use efficiency than the northern spring maize region. The Huang-Huai-Hai Plain spring and summer maize region was increasingly crucial for Chinese maize production. Both RE and AE in the Huang-Huai-Hai Plain spring and summer maize region were lower than the national average due to excessive fertilizer application. This was especially obvious during 2000s when RE and AE in the region were only 23.5% and 6.7 kg·kg-1 respectively, both much lower than other regions. Moreover, balanced fertilizer application, high-efficiency nitrogen genotype and improved agricultural management were main alternatives to enhancing SNF use efficiency, reducing resources waste and alleviating environmental pollution in China.
2013, 21(10): 1193-1201.
doi: 10.3724/SP.J.1011.2013.30105
Abstract:
An upland red soil experiment was conducted from 2006 to 2012 to determine the effects of rice straw mulching on seasonal drought resistance of summer maize. The study was conducted at the Taoyuan Agro-ecological Experimental Station of Chinese Academy of Sciences, Hunan Province, China. Rice straw was applied at the rates of 0 (CK), 5 000 kg·hm-2 (T1), 10 000 kg·hm-2 (T2) and 15 000 kg·hm-2 (T3) in field plots. The results showed that compared with CK (control), total soil available moisture in T1, T2 and T3 increased by 6.8% (P > 0.05), 19.3% (P > 0.05) and 28.4% (P < 0.05), respectively. In 2012, maize photosynthetic rate at filling stages in T1, T2 and T3 respectively increased by 24.1%, 40.3% and 53.8%. Also T1, T2 and T3 were respectively higher in photosynthetic rate than CK by 20.0%, 40.3% and 37.9% at maturity stage. At drought occurrence rate of 18.2% per ten days, there was no significant difference in maize yield between rice straw mulching and CK. Yield difference was significant (P < 0.05) when drought occurrence rate was 18.2% 63.6% per ten days. When drought occurrence rate was 18.2% 36.4% per ten days, T1 had the maximum yield. When drought occurrence rate reached 54.5% per ten days, T3 produced the maximum yield. When drought occurrence rate exceeded 63.6% per ten day, rice straw mulching was no longer suitable for resisting drought. The recommended amount of straw mulch in the southern hilly red soils was 5 000 kg·hm-2.
An upland red soil experiment was conducted from 2006 to 2012 to determine the effects of rice straw mulching on seasonal drought resistance of summer maize. The study was conducted at the Taoyuan Agro-ecological Experimental Station of Chinese Academy of Sciences, Hunan Province, China. Rice straw was applied at the rates of 0 (CK), 5 000 kg·hm-2 (T1), 10 000 kg·hm-2 (T2) and 15 000 kg·hm-2 (T3) in field plots. The results showed that compared with CK (control), total soil available moisture in T1, T2 and T3 increased by 6.8% (P > 0.05), 19.3% (P > 0.05) and 28.4% (P < 0.05), respectively. In 2012, maize photosynthetic rate at filling stages in T1, T2 and T3 respectively increased by 24.1%, 40.3% and 53.8%. Also T1, T2 and T3 were respectively higher in photosynthetic rate than CK by 20.0%, 40.3% and 37.9% at maturity stage. At drought occurrence rate of 18.2% per ten days, there was no significant difference in maize yield between rice straw mulching and CK. Yield difference was significant (P < 0.05) when drought occurrence rate was 18.2% 63.6% per ten days. When drought occurrence rate was 18.2% 36.4% per ten days, T1 had the maximum yield. When drought occurrence rate reached 54.5% per ten days, T3 produced the maximum yield. When drought occurrence rate exceeded 63.6% per ten day, rice straw mulching was no longer suitable for resisting drought. The recommended amount of straw mulch in the southern hilly red soils was 5 000 kg·hm-2.
XIAO Xiao-Ping,
TANG Hai-Ming,
NIE Ze-Min,
GUO Li-Jun,
LIU Zheng-Peng,
TANG Wen-Guang,
WANG Ke,
YANG Guang-Li
2013, 21(10): 1202-1208.
doi: 10.3724/SP.J.1011.2013.30463
Abstract:
Research on total organic carbon (TOC), carbon pool activivty (CPA) and carbon pool management index (CPMI) of paddy fields with different double cropping rice patterns could enhance the exploitation of winter cover crop and the assessment of paddy rice cropping patterns. This paper discussed soil TOC, CPA and CPMI in double cropping rice systems with straw recycling of different winter cover crops. Experiments were conducted in field plot trials of ryegrass and double cropping rice (T1), Chinese milk vetch and double cropping rice (T2), rape and double cropping rice (T3) and fallow and double cropping rice (CK). The results showed that recycling of winter cover crop straws significantly increased soil TOC and CPA over CK. The order of TOC content and CPA under different cropping patterns was T2 > T1 > T3 > CK at the early and later rice harvest stages. Compared with CK, T1, T2 and T3 averagely increased soil TOC content respectively by 6.73%, 10.53% and 4.79% at early rice harvest in 2011 and 2012 and by 4.16%, 6.20% and 2.37% at later rice harvest in 2011 and 2012. However, no significant difference existed in TOC content among T1, T2 and T3 treatments. The CPA under treatments T1 and T2 with winter cover crop straw recycling was also higher than that of CK. Compared with CK, CPA under treatments T1 and T2 on average increased respectively by 10.52% and 21.52% at early rice harvest and by 11.99% and 15.59% at later rice harvest in 2011 and 2012. Also compared with CK, CPA, activity index (AI), carbon pool index (CPI) and CPMI under treatments T1, T2 and T3 improved at early and later rice harvest stages. The results further showed that CPA, AI, CPI and CPMI increased with winter cover crop straw recycling. The order of CPA, AI, CPI and CPMI under the different cropping patterns were T2 > T1 > T3 > CK. Thus winter cover crop straw recycling significantly influenced TOC content, AC and CPMI in paddy fields. Winter cover crop straw recycling had the best effect with Chinese milk vetch, followed by ryegrass and then rape.
Research on total organic carbon (TOC), carbon pool activivty (CPA) and carbon pool management index (CPMI) of paddy fields with different double cropping rice patterns could enhance the exploitation of winter cover crop and the assessment of paddy rice cropping patterns. This paper discussed soil TOC, CPA and CPMI in double cropping rice systems with straw recycling of different winter cover crops. Experiments were conducted in field plot trials of ryegrass and double cropping rice (T1), Chinese milk vetch and double cropping rice (T2), rape and double cropping rice (T3) and fallow and double cropping rice (CK). The results showed that recycling of winter cover crop straws significantly increased soil TOC and CPA over CK. The order of TOC content and CPA under different cropping patterns was T2 > T1 > T3 > CK at the early and later rice harvest stages. Compared with CK, T1, T2 and T3 averagely increased soil TOC content respectively by 6.73%, 10.53% and 4.79% at early rice harvest in 2011 and 2012 and by 4.16%, 6.20% and 2.37% at later rice harvest in 2011 and 2012. However, no significant difference existed in TOC content among T1, T2 and T3 treatments. The CPA under treatments T1 and T2 with winter cover crop straw recycling was also higher than that of CK. Compared with CK, CPA under treatments T1 and T2 on average increased respectively by 10.52% and 21.52% at early rice harvest and by 11.99% and 15.59% at later rice harvest in 2011 and 2012. Also compared with CK, CPA, activity index (AI), carbon pool index (CPI) and CPMI under treatments T1, T2 and T3 improved at early and later rice harvest stages. The results further showed that CPA, AI, CPI and CPMI increased with winter cover crop straw recycling. The order of CPA, AI, CPI and CPMI under the different cropping patterns were T2 > T1 > T3 > CK. Thus winter cover crop straw recycling significantly influenced TOC content, AC and CPMI in paddy fields. Winter cover crop straw recycling had the best effect with Chinese milk vetch, followed by ryegrass and then rape.
2013, 21(10): 1209-1216.
doi: 10.3724/SP.J.1011.2013.21136
Abstract:
Green manure has been important as a complete source of high-quality nutrients, bio-fertilizers and organic fertilizers. Generally, paddy fields in southern China have been laid fallow in winter. This has generally amounted to waste of land resources for a significant portion of the year. Agricultural non-point source pollution caused by overuse of chemical pesticides with low-use efficiencies has had serious environmental pollution. Hence the large-scale promotion of winter green manure was crucial in achieving sustainable agricultural development. To explore the ecological role of winter green manure in improving soil nutrients, an experimental study was conducted where green plants (milk-vetch, ryegras, rapeseed) were planted during winter and plowed into rice fields 15 days before early rice planting for eight consecutive years. A continuous winter fallow was used as the control experiment. The results showed that average rice yield in fields with winter green manure was higher than in winter fallow fields. The most obvious increase was in the milk-vetch treatment (10.48%), followed by the rapeseed treatment (7.31%) and then the ryegrass treatment (5.76%). pH and alkaline hydrolysis nitrogen in the milk-vetch treatment was highest. pH and alkaline hydrolysis nitrogen increased by 0.58% 1.37% and 6.59% 35.35%, respectively. Organic matter, available P, available K and C/N ratio in soils with ryegrasse treatment were highest. Soil organic matter in ryegrass treatment was higher than that in other treatments by 2.99% 4.98%. Alao available P increased by 19.25% 31.05%, available K by 16.97% 22.15% and C/N ratio by 0.97% 6.61%. Rice yield highly significantly correlated (P < 0.01) with per-panicle spikelets, seed setting rate, grain weight, alkaline hydrolysis nitrogen and available P; and was significantly correlated (P < 0.05) with per-panicle grains, organic matter, available K and organic carbon; while it had no significant correlation with panicle length, effective panicle, soil pH and C/N ratio. The study showed extremely close correlation among the respective rice yield varibles and soil nutrients. On the whole, the study showed that winter green manure improved soil fertility and enhanced rice yield. Milk-vetch, ryegrass and rapeseed used in the experiment respectively belong to Leguminosae, Gramineae and Brassicaceae. These crops constituted the traditionally common winter green manure species in the study area. The study was critical for increased agricultural productivity, improved soil quality and increased farmer income. The paper provided the theoretical basis for improving soil fertility and land utilization for sustainable agricultural development in China.
Green manure has been important as a complete source of high-quality nutrients, bio-fertilizers and organic fertilizers. Generally, paddy fields in southern China have been laid fallow in winter. This has generally amounted to waste of land resources for a significant portion of the year. Agricultural non-point source pollution caused by overuse of chemical pesticides with low-use efficiencies has had serious environmental pollution. Hence the large-scale promotion of winter green manure was crucial in achieving sustainable agricultural development. To explore the ecological role of winter green manure in improving soil nutrients, an experimental study was conducted where green plants (milk-vetch, ryegras, rapeseed) were planted during winter and plowed into rice fields 15 days before early rice planting for eight consecutive years. A continuous winter fallow was used as the control experiment. The results showed that average rice yield in fields with winter green manure was higher than in winter fallow fields. The most obvious increase was in the milk-vetch treatment (10.48%), followed by the rapeseed treatment (7.31%) and then the ryegrass treatment (5.76%). pH and alkaline hydrolysis nitrogen in the milk-vetch treatment was highest. pH and alkaline hydrolysis nitrogen increased by 0.58% 1.37% and 6.59% 35.35%, respectively. Organic matter, available P, available K and C/N ratio in soils with ryegrasse treatment were highest. Soil organic matter in ryegrass treatment was higher than that in other treatments by 2.99% 4.98%. Alao available P increased by 19.25% 31.05%, available K by 16.97% 22.15% and C/N ratio by 0.97% 6.61%. Rice yield highly significantly correlated (P < 0.01) with per-panicle spikelets, seed setting rate, grain weight, alkaline hydrolysis nitrogen and available P; and was significantly correlated (P < 0.05) with per-panicle grains, organic matter, available K and organic carbon; while it had no significant correlation with panicle length, effective panicle, soil pH and C/N ratio. The study showed extremely close correlation among the respective rice yield varibles and soil nutrients. On the whole, the study showed that winter green manure improved soil fertility and enhanced rice yield. Milk-vetch, ryegrass and rapeseed used in the experiment respectively belong to Leguminosae, Gramineae and Brassicaceae. These crops constituted the traditionally common winter green manure species in the study area. The study was critical for increased agricultural productivity, improved soil quality and increased farmer income. The paper provided the theoretical basis for improving soil fertility and land utilization for sustainable agricultural development in China.
2013, 21(10): 1217-1224.
doi: 10.3724/SP.J.1011.2013.30268
Abstract:
As an important component of ecosystem carbon (C) budget, soil respiration is critical for soil-plant C cycle. As an entirely different cropping system, greenhouse vegetable system is characterized as excessive nutrient input, intensive land use, high temperature and high humidity and airtight environment. All of these factors have considerable influence on soil respiration rate and C cycle. With increasing greenhouse vegetable production in China, CO2 emission in greenhouse vegetable systems can not be ignored in the whole agricultural production system. In addition to studies of seasonal variations of soil respiration rate in greenhouse vegetable fields, understanding daily variation characteristics of soil respiration rate can enhance the estimation of the effects of CO2 emission on the environment and crop growth in greenhouse vegetable system. Thus this study investigated the driving factors and characteristics of daily dynamics of soil respiration rate under different organic manure and N (nitrogen) fertilizer inputs in a greenhouse vegetable field. The infrared gas analyzer (IRGA)-closed chamber technique was used to analyze greenhouse vegetable conditions in 2009 2010 in Shouguang City, Shandong Province. Four measurements were taken to determine daily variations in soil respiration rate during the main growth period. The results showed that the application of organic manure and wheat straw significantly improved soil respiration rate, especially in the treatments with high N fertilizer where the soil respiration rates were highest. Although some differences existed in soil respiration rate among different treatments in different seasons, daily dynamics of soil respiration rate were similar for all the treatments. With rising temperature, soil respiration rate increased steadily and the highest soil respiration rate occurred 14:00 17:00, which was later than the highest temperature. Also with rising temperature, CO2 increased steadily. High temperature and CO2 concentration inhibited soil respiration rate in greenhouse vegetable fields. Based on the four measurements over the study period, soil respiration rates during 8:00 11:00 a.m. were similar to daily average rates. This suggested that soil respiration rate during 8:00 11:00 a.m. could be used to estimate CO2 emission in greenhouse fields. Fertilization, temperature and near-ground CO2 concentration were the main driving factors of the daily dynamics of soil respiration rate. Optimal regulation was critical for reducing CO2 emission and enhancing sustainable development of greenhouse vegetable production in China.
As an important component of ecosystem carbon (C) budget, soil respiration is critical for soil-plant C cycle. As an entirely different cropping system, greenhouse vegetable system is characterized as excessive nutrient input, intensive land use, high temperature and high humidity and airtight environment. All of these factors have considerable influence on soil respiration rate and C cycle. With increasing greenhouse vegetable production in China, CO2 emission in greenhouse vegetable systems can not be ignored in the whole agricultural production system. In addition to studies of seasonal variations of soil respiration rate in greenhouse vegetable fields, understanding daily variation characteristics of soil respiration rate can enhance the estimation of the effects of CO2 emission on the environment and crop growth in greenhouse vegetable system. Thus this study investigated the driving factors and characteristics of daily dynamics of soil respiration rate under different organic manure and N (nitrogen) fertilizer inputs in a greenhouse vegetable field. The infrared gas analyzer (IRGA)-closed chamber technique was used to analyze greenhouse vegetable conditions in 2009 2010 in Shouguang City, Shandong Province. Four measurements were taken to determine daily variations in soil respiration rate during the main growth period. The results showed that the application of organic manure and wheat straw significantly improved soil respiration rate, especially in the treatments with high N fertilizer where the soil respiration rates were highest. Although some differences existed in soil respiration rate among different treatments in different seasons, daily dynamics of soil respiration rate were similar for all the treatments. With rising temperature, soil respiration rate increased steadily and the highest soil respiration rate occurred 14:00 17:00, which was later than the highest temperature. Also with rising temperature, CO2 increased steadily. High temperature and CO2 concentration inhibited soil respiration rate in greenhouse vegetable fields. Based on the four measurements over the study period, soil respiration rates during 8:00 11:00 a.m. were similar to daily average rates. This suggested that soil respiration rate during 8:00 11:00 a.m. could be used to estimate CO2 emission in greenhouse fields. Fertilization, temperature and near-ground CO2 concentration were the main driving factors of the daily dynamics of soil respiration rate. Optimal regulation was critical for reducing CO2 emission and enhancing sustainable development of greenhouse vegetable production in China.
2013, 21(10): 1225-1232.
doi: 10.3724/SP.J.1011.2013.30291
Abstract:
Soil water is a critical factor for vegetation rehabilitation and eco-environmental construction in karst mountain regions. The dynamics of water content in soil profiles with different geological backgrounds were analyzed in peak-cluster depression zones in karst region of Northwest Guangxi. The study was conducted in maize-soybean rotation fields in Guzhou Village with pure limestone geology and in mulberry tree fields in Mulun Nature Reserve with dolomite limestone geology. The parameters of rainfall, wind speed, wind direction, temperature, humidity and atmospheric pressure were recorded in meteorological stations with multi-functional meteorological sensors. Volumetric soil water content was monitored at soil depths of 5 cm, 10 cm, 20 cm, 30 cm, 40 cm, 50 cm, 70 cm, and 90 cm by automatic gauge systems and data collected every 30 min using CR1000 data acquisition device. Soils were sampled three times during the study using circular knife (AZ-HSS-100-24) at corresponding water monitoring depths. Then bulk density, capillary water capacity and saturated water content were determined using the drying method. Also saturated conductivity for fixed water level and soil water storage were calculated. Dynamic variations in soil water at different soil layers (0-90 cm) in the farmland ecosystems in karst peak-cluster depressions in Guzhou Village and Mulun Nature Reserve were then discussed in relation to atmospheric precipitation, soil water content and other variables in 2009 and 2010. The results showed that while soil bulk density, capillary water capacity and saturated water content increased, non-capillary porosity and saturated conductivity decreased with increasing soil depth. Also higher soil bulk density corresponded with lower saturated conductivity. The physical properties of 0-30 cm soil layer in peak-cluster depression zones did not favor water storage and regulation functions at both investigated sites. Soil water content was not only high, but also increased with increasing soil depth. Soil water contents in 2009 and 2010 showed evident layer trends for the active layer, sub-active layer and stable layer. This was attributed to the soil clayey texture of peak-cluster depression areas. Variations in soil water content were little different for the two study sites. In pure limestone geology, the below 40 cm soil layer was relatively stable in 2009 while the below 30 cm soil layer was relatively stable in 2010. In dolomitic limestone geology, the below 20 cm soil layer was relatively stable in both 2009 and 2010. The storage and regulation functions of soils in peak-cluster depression zones could had been overestimated due to heavy nature of the soil layers. Because soil water storage was influenced by rainfall, evaporation and plant transpiration, it showed variations characteristic of these factors. Periods of relative stabilization, consumption and supplement of soil water storage were noted in 2009 and 2010, but with one month difference in occurrence between two years. The time difference was mainly attributed to rainfall distribution characteristics in the regions. Soil water deficit compensation and rehabilitation was most effective under moderate rainfall intensity and long, heavy rainfall conditions. Light and heavy rains had less effect on soil water because they hardly infiltrated down to lower soil layers. Long and heavy rains were, however, sufficient to replenish soil water in both the upper and lower soil layers.
Soil water is a critical factor for vegetation rehabilitation and eco-environmental construction in karst mountain regions. The dynamics of water content in soil profiles with different geological backgrounds were analyzed in peak-cluster depression zones in karst region of Northwest Guangxi. The study was conducted in maize-soybean rotation fields in Guzhou Village with pure limestone geology and in mulberry tree fields in Mulun Nature Reserve with dolomite limestone geology. The parameters of rainfall, wind speed, wind direction, temperature, humidity and atmospheric pressure were recorded in meteorological stations with multi-functional meteorological sensors. Volumetric soil water content was monitored at soil depths of 5 cm, 10 cm, 20 cm, 30 cm, 40 cm, 50 cm, 70 cm, and 90 cm by automatic gauge systems and data collected every 30 min using CR1000 data acquisition device. Soils were sampled three times during the study using circular knife (AZ-HSS-100-24) at corresponding water monitoring depths. Then bulk density, capillary water capacity and saturated water content were determined using the drying method. Also saturated conductivity for fixed water level and soil water storage were calculated. Dynamic variations in soil water at different soil layers (0-90 cm) in the farmland ecosystems in karst peak-cluster depressions in Guzhou Village and Mulun Nature Reserve were then discussed in relation to atmospheric precipitation, soil water content and other variables in 2009 and 2010. The results showed that while soil bulk density, capillary water capacity and saturated water content increased, non-capillary porosity and saturated conductivity decreased with increasing soil depth. Also higher soil bulk density corresponded with lower saturated conductivity. The physical properties of 0-30 cm soil layer in peak-cluster depression zones did not favor water storage and regulation functions at both investigated sites. Soil water content was not only high, but also increased with increasing soil depth. Soil water contents in 2009 and 2010 showed evident layer trends for the active layer, sub-active layer and stable layer. This was attributed to the soil clayey texture of peak-cluster depression areas. Variations in soil water content were little different for the two study sites. In pure limestone geology, the below 40 cm soil layer was relatively stable in 2009 while the below 30 cm soil layer was relatively stable in 2010. In dolomitic limestone geology, the below 20 cm soil layer was relatively stable in both 2009 and 2010. The storage and regulation functions of soils in peak-cluster depression zones could had been overestimated due to heavy nature of the soil layers. Because soil water storage was influenced by rainfall, evaporation and plant transpiration, it showed variations characteristic of these factors. Periods of relative stabilization, consumption and supplement of soil water storage were noted in 2009 and 2010, but with one month difference in occurrence between two years. The time difference was mainly attributed to rainfall distribution characteristics in the regions. Soil water deficit compensation and rehabilitation was most effective under moderate rainfall intensity and long, heavy rainfall conditions. Light and heavy rains had less effect on soil water because they hardly infiltrated down to lower soil layers. Long and heavy rains were, however, sufficient to replenish soil water in both the upper and lower soil layers.
2013, 21(10): 1233-1240.
doi: 10.3724/SP.J.1011.2013.21077
Abstract:
Tamarix chinensis, a pioneering native salt-tolerant plant in abandoned coastal saline lands, has high potential as eco-engineering plant species for re-vegetation and soil quality improvement. However, field experiments on the effectiveness of T. chinensis in re-restoration of saline lands along the coastal areas of China have been largely lacking. T. chinensis was planted in 2005, 2007 and 2009 to assess the effectiveness of plants on vegetation and saline soil restoration in this study. The individual biomass, sequenced carbon amount, herb species diversity and soil characteristics of T. chinensis plantations with different planting years and of adjacent abandoned lands without T. chinensis were investigated. The results showed that T. chinensis grew well in the research area and with increasing individual biomass during the experimentation period. T. chinensis plantations produced significant ecological benefits which increased plot vegetation carbon density from 4.78 t(C)·hm-2 in 3-year plots to 5.56 t(C)·hm-2 in 5-year plots and then to 6.89 t(C)·hm-2 in 7-year plots. On the average, there was only 0.98 t(C)·hm-2 in abandoned lands without T. chinensis. Significant soil quality improvement was indicated by lower saltiness and higher organic matter and available N and K in T. chinensis plantation lands. Salt content in the 0 10 cm soil layer of abandoned lands was 10.53 g·kg-1. It was 3.35 g·kg-1 in the 3-year plots, 1.86 g·kg-1 in the 5-year plots and 5.54 g·kg-1 in the 7-year plots with T. chinensis. Compare with abandoned lands, soil available K in the 0 5 cm and 5 15 cm soil layer in the 7-year plots respectively increased by 65.59% and 28.90%. In addition, T. chinensis played a significant "eco-engineering" role in terms of increasing volume and species of grass during T. chinensis plant development. Whereas only 8 grass species existed in the abandoned lands without T. chinensis, a total of 15 grass species existed in the 7-year plot with T. chinensis plantation. However, other important salt-tolerant species decreased in T. chinensis plots. Colon plants like Aeluropus sinensis and Ixeris polycephala became more dominant than seed plants such as Suaeda salsa after planting T. chinensis. This suggested that T. chinensis plant progressively alleviated salt stress in the coastal environments. The study demonstrated via field experiments that T. chinensis was effective in vegetation regeneration, soil enhancement and carbon sequestration in saline lands.
Tamarix chinensis, a pioneering native salt-tolerant plant in abandoned coastal saline lands, has high potential as eco-engineering plant species for re-vegetation and soil quality improvement. However, field experiments on the effectiveness of T. chinensis in re-restoration of saline lands along the coastal areas of China have been largely lacking. T. chinensis was planted in 2005, 2007 and 2009 to assess the effectiveness of plants on vegetation and saline soil restoration in this study. The individual biomass, sequenced carbon amount, herb species diversity and soil characteristics of T. chinensis plantations with different planting years and of adjacent abandoned lands without T. chinensis were investigated. The results showed that T. chinensis grew well in the research area and with increasing individual biomass during the experimentation period. T. chinensis plantations produced significant ecological benefits which increased plot vegetation carbon density from 4.78 t(C)·hm-2 in 3-year plots to 5.56 t(C)·hm-2 in 5-year plots and then to 6.89 t(C)·hm-2 in 7-year plots. On the average, there was only 0.98 t(C)·hm-2 in abandoned lands without T. chinensis. Significant soil quality improvement was indicated by lower saltiness and higher organic matter and available N and K in T. chinensis plantation lands. Salt content in the 0 10 cm soil layer of abandoned lands was 10.53 g·kg-1. It was 3.35 g·kg-1 in the 3-year plots, 1.86 g·kg-1 in the 5-year plots and 5.54 g·kg-1 in the 7-year plots with T. chinensis. Compare with abandoned lands, soil available K in the 0 5 cm and 5 15 cm soil layer in the 7-year plots respectively increased by 65.59% and 28.90%. In addition, T. chinensis played a significant "eco-engineering" role in terms of increasing volume and species of grass during T. chinensis plant development. Whereas only 8 grass species existed in the abandoned lands without T. chinensis, a total of 15 grass species existed in the 7-year plot with T. chinensis plantation. However, other important salt-tolerant species decreased in T. chinensis plots. Colon plants like Aeluropus sinensis and Ixeris polycephala became more dominant than seed plants such as Suaeda salsa after planting T. chinensis. This suggested that T. chinensis plant progressively alleviated salt stress in the coastal environments. The study demonstrated via field experiments that T. chinensis was effective in vegetation regeneration, soil enhancement and carbon sequestration in saline lands.
2013, 21(10): 1241-1248.
doi: 10.3724/SP.J.1011.2013.30534
Abstract:
Cotton fiber micronaire is an important fiber trait which is directly related to yarn quality. This element of quality is the main limiting factor in cotton fiber quality improvement in the Yangtze River Valley. The optimal arrangement of a regional trial scheme is based on representative trial location identification. This is critical in enhancing both micronaire selection efficiency and regional trial cost-savings. Biplot GGE analysis has been the most useful statistical and visual tool for trial location evaluation and representative location selection, and it has been extensively adopted in cultivar stability and trial location similarity analysis in several crops. So far, however, little has been done in terms of cotton regional trial location evaluation based on fiber micronaire selection. The objective of this study was to single out ideal trial locations in cotton micronaire selection using biplot GGE analysis. The method was applied to 27 independent sets of cotton variety regional trials in 15 trail locations in the Yangtze River Valley in 2000 2010. Based on the evaluation variables of desirability indexes for fiber micronaire selection, the order of the 15 trial locations was Jingzhou City > Huanggang City > Nantong City > Jiujiang City > Yueyang City > Shehong City > Changde City > Anqing City > Wuhan City > Nanyang City > Nanjing City > Cixi City > Xiangyang City > Jianyang City > Yancheng City. Jingzhou City of Hubei Province was the most ideal trial location, while Huanggang City of Hubei Province, Nantong City of Jiangsu Province and Jiujiang City of Jiangxi Province were the ideal trial locations. It implied that these locations were the most effective for eurytopic cotton cultivar selection and regional test points of optimal cultivar identification based on cotton fiber micronaire in the Yangtze River Valley. On the other hand, the cotton trial locations in Jiangsu and Zhejiang provincial coastal fields (Yancheng and Cixi) were not suitable for cotton fiber micronaire selection in the Yangtze River Valley. This article has fully demonstrated the efficiency of biplot GGE application in regional trial environment evaluation and therefore laid the theoretical basis for decision-making regarding fiber micronaire selection in regional/national cotton trials schemes in the Yangtze River Valley.
Cotton fiber micronaire is an important fiber trait which is directly related to yarn quality. This element of quality is the main limiting factor in cotton fiber quality improvement in the Yangtze River Valley. The optimal arrangement of a regional trial scheme is based on representative trial location identification. This is critical in enhancing both micronaire selection efficiency and regional trial cost-savings. Biplot GGE analysis has been the most useful statistical and visual tool for trial location evaluation and representative location selection, and it has been extensively adopted in cultivar stability and trial location similarity analysis in several crops. So far, however, little has been done in terms of cotton regional trial location evaluation based on fiber micronaire selection. The objective of this study was to single out ideal trial locations in cotton micronaire selection using biplot GGE analysis. The method was applied to 27 independent sets of cotton variety regional trials in 15 trail locations in the Yangtze River Valley in 2000 2010. Based on the evaluation variables of desirability indexes for fiber micronaire selection, the order of the 15 trial locations was Jingzhou City > Huanggang City > Nantong City > Jiujiang City > Yueyang City > Shehong City > Changde City > Anqing City > Wuhan City > Nanyang City > Nanjing City > Cixi City > Xiangyang City > Jianyang City > Yancheng City. Jingzhou City of Hubei Province was the most ideal trial location, while Huanggang City of Hubei Province, Nantong City of Jiangsu Province and Jiujiang City of Jiangxi Province were the ideal trial locations. It implied that these locations were the most effective for eurytopic cotton cultivar selection and regional test points of optimal cultivar identification based on cotton fiber micronaire in the Yangtze River Valley. On the other hand, the cotton trial locations in Jiangsu and Zhejiang provincial coastal fields (Yancheng and Cixi) were not suitable for cotton fiber micronaire selection in the Yangtze River Valley. This article has fully demonstrated the efficiency of biplot GGE application in regional trial environment evaluation and therefore laid the theoretical basis for decision-making regarding fiber micronaire selection in regional/national cotton trials schemes in the Yangtze River Valley.
2013, 21(10): 1249-1256.
doi: 10.3724/SP.J.1011.2013.30132
Abstract:
Peach (Prunus persica) is a popular temperate fruit now cultivated worldwide. China ranks first in the world both in peach planted area and production. In the last 10 years, peach cultivation has developed quickly and spread to most of northern China. The problem is that the flowering biology of peach cultivars has been insufficiently studied and poor pollination has often caused low fruit set and yield for peach trees in greenhouses. In order to evaluate the flowering biology of different peach cultivars in greenhouses, the flowering dynamics, anther dehiscence, pollen quantity, pollen viability, and stigma receptivity of four major peach cultivars (Prunus persica "Okubo", P. persica "Zaolupan", P. persica "Ruiguang 5" and P. persica "90342") were investigated in greenhouses in Beijing. In the study, 80 flowers for each cultivar were studied for the timing of different flowering stages, 18 flowers were used to obsever anther dehiscence development, 50 anthers were used to count pollen grains number per anther, 50 flowers were used to count anthers number per flower. A TTC test was used to assess pollen viability, and a benzidine-hydrogen peroxide test was used to assess stigma receptivity. The results showed that the start time of blooming varied by 8 days among cultivars, which were ranked (from earliest to latest) - "Ruiguang 5", "Zaolupan", "Okubo", "90342". Cultivar "90342" had a two-day full-bloom stage for single flower, which was significantly shorter than other three cultivars. The full-bloom stage of the other three cultivars lasted for 4 5 days. The starting time, duration, and peak period of anther dehiscence varied among the four cultivars. Significant variation in pollen quantity was also observed. Cultivar "90342" had the largest number of pollen grains per flower (100 360 ± 8 017), followed by "Okubo" (91 485 ± 8 002), "Ruiguang 5" (73 245 ± 5 034) and "Zaolupan" (59 609 ± 5 048). The highest pollen viability was found on the day when the flower opened fully in "Okubo", "Ruiguang 5", and "90342", which were 44.8% ± 3.1%, 52.4% ± 4.2% and 32.8% ± 4.5% respectively. The pollen of "Zaolupan" had the highest viability 63.3% ± 3.7% one day after the flower opened fully. Pollen viability lasted only three days in "Ruiguang 5" and "90342", while "Okubo" and "Zaolupan" had a greater longevity of 6 7 days. The receptive period of the stigma remained for 6 7 days, with the strongest receptivity 3 4 days after the flower opened fully in "Okubo", "Zaolupan" and "Ruiguang 5". However, the receptive period of cultivar "90342" lasted for just 3 days, with the greatest receptivity 2 days after the flower opened fully. This study contributed new information not only for differences in pollination biology among the four cultivars and for the scientific management of greenhouse peaches, but also for the broader study of pollination mechanisms.
Peach (Prunus persica) is a popular temperate fruit now cultivated worldwide. China ranks first in the world both in peach planted area and production. In the last 10 years, peach cultivation has developed quickly and spread to most of northern China. The problem is that the flowering biology of peach cultivars has been insufficiently studied and poor pollination has often caused low fruit set and yield for peach trees in greenhouses. In order to evaluate the flowering biology of different peach cultivars in greenhouses, the flowering dynamics, anther dehiscence, pollen quantity, pollen viability, and stigma receptivity of four major peach cultivars (Prunus persica "Okubo", P. persica "Zaolupan", P. persica "Ruiguang 5" and P. persica "90342") were investigated in greenhouses in Beijing. In the study, 80 flowers for each cultivar were studied for the timing of different flowering stages, 18 flowers were used to obsever anther dehiscence development, 50 anthers were used to count pollen grains number per anther, 50 flowers were used to count anthers number per flower. A TTC test was used to assess pollen viability, and a benzidine-hydrogen peroxide test was used to assess stigma receptivity. The results showed that the start time of blooming varied by 8 days among cultivars, which were ranked (from earliest to latest) - "Ruiguang 5", "Zaolupan", "Okubo", "90342". Cultivar "90342" had a two-day full-bloom stage for single flower, which was significantly shorter than other three cultivars. The full-bloom stage of the other three cultivars lasted for 4 5 days. The starting time, duration, and peak period of anther dehiscence varied among the four cultivars. Significant variation in pollen quantity was also observed. Cultivar "90342" had the largest number of pollen grains per flower (100 360 ± 8 017), followed by "Okubo" (91 485 ± 8 002), "Ruiguang 5" (73 245 ± 5 034) and "Zaolupan" (59 609 ± 5 048). The highest pollen viability was found on the day when the flower opened fully in "Okubo", "Ruiguang 5", and "90342", which were 44.8% ± 3.1%, 52.4% ± 4.2% and 32.8% ± 4.5% respectively. The pollen of "Zaolupan" had the highest viability 63.3% ± 3.7% one day after the flower opened fully. Pollen viability lasted only three days in "Ruiguang 5" and "90342", while "Okubo" and "Zaolupan" had a greater longevity of 6 7 days. The receptive period of the stigma remained for 6 7 days, with the strongest receptivity 3 4 days after the flower opened fully in "Okubo", "Zaolupan" and "Ruiguang 5". However, the receptive period of cultivar "90342" lasted for just 3 days, with the greatest receptivity 2 days after the flower opened fully. This study contributed new information not only for differences in pollination biology among the four cultivars and for the scientific management of greenhouse peaches, but also for the broader study of pollination mechanisms.
2013, 21(10): 1257-1263.
doi: 10.3724/SP.J.1011.2013.30337
Abstract:
Heavy metal adsorption and desorption behaviors significantly influence the transformation, migration and fate of heavy metals in soils and ecological environment, which in turn affects the quality of agricultural products and human environment. Although much research has been conducted on soil heavy metal adsorption and desorption, less work has been done relating to soil heavy metal adsorption and desorption characteristics under different land use types. Soils under different land use types could have significant differences in pH, organic matter content, clay content and microbe species. This in turn not only affects the physical and chemical behaviors of heavy metals, but also restricts the morphology, migration, bioavailability and toxicity of these metals. Soil heavy metal adsorption is a dynamic equilibrium process. Soil properties, heavy metal types and environmental factors influence the adsorption and desorption capacity of soil heavy metals. This paper selected three different land use types (woodland, grassland and farmland) in Wuhu City for investigation. The adsorption and desorption processes of soil copper (Cu2+) and cadmium (Cd2+) ions under different land use types were studied using the bath method and a locally-made dynamic adsorption device. The study discussed Cu2+ and Cd2+ adsorption kinetics in soils under three land use types. It laid the theoretical basis for further studies on land use and soil heavy metal adsorption and desorption mechanisms. The results showed that Cu2+ and Cd2+ adsorption capacities in the three soil conditions increased with increasing equilibrium concentration. The adsorption capacities of Cu2+ and Cd2+ in farmland soils were higher than in woodland and grassland soils. The desorption of Cu2+ and Cd2+ in soil under different land use types increased with increasing adsorption of the ions. A positive linear correlation was noted between ion adsorption and desorption in different soil conditions. The absorbed Cu2+ and Cd2+ by soil was incompletely desorbed due to fixation of part heavy metals ions in soils. The amount of fixed exogenous heavy metal ions reflected the soil fixing capacity of the heavy metal ions. The fixing capacities of three soil conditions for the two heavy metal ions were non-identical. The fixed amounts of Cu2+ were 147.2 mg·kg-1, 118.5 mg·kg-1 and 61.9 mg·kg-1, and those of Cd2+ were 20.12 mg·kg-1, 33.33 mg·kg-1 and 9.97 mg·kg-1 in woodland, grassland and farmland conditions, respectively. The Langmuir equation and Freunlich adsorption equations were used to fit the Cu2+ and Cd2+ processes in different soil conditions. While the Cu2+ adsorption process was fitted using the Langmuir equation, that of Cd2+ was fitted using the Freunlich equation. Both Cu2+ and Cd2+ desorption in farmland soil were higher than those in woodland and grassland soils. The dynamic adsorptions of Cu2+ and Cd2+ in the three conditions showed a rapid reaction process. Also the adsorption reaction tended to balance out with time. The adsorption kinetics of heavy metals in the soils fitted well with the double constant equation and the Elovich equation. The adsorption of Cu2+ and Cd2+ in the three soils was related with soil clay content, organic matter content, pH and CEC. This was driven by surface soil adsorption force, properties of hydroxyl and carboxyl groups, soil surface charges, soil solution exchangeable ion concentrations, etc.
Heavy metal adsorption and desorption behaviors significantly influence the transformation, migration and fate of heavy metals in soils and ecological environment, which in turn affects the quality of agricultural products and human environment. Although much research has been conducted on soil heavy metal adsorption and desorption, less work has been done relating to soil heavy metal adsorption and desorption characteristics under different land use types. Soils under different land use types could have significant differences in pH, organic matter content, clay content and microbe species. This in turn not only affects the physical and chemical behaviors of heavy metals, but also restricts the morphology, migration, bioavailability and toxicity of these metals. Soil heavy metal adsorption is a dynamic equilibrium process. Soil properties, heavy metal types and environmental factors influence the adsorption and desorption capacity of soil heavy metals. This paper selected three different land use types (woodland, grassland and farmland) in Wuhu City for investigation. The adsorption and desorption processes of soil copper (Cu2+) and cadmium (Cd2+) ions under different land use types were studied using the bath method and a locally-made dynamic adsorption device. The study discussed Cu2+ and Cd2+ adsorption kinetics in soils under three land use types. It laid the theoretical basis for further studies on land use and soil heavy metal adsorption and desorption mechanisms. The results showed that Cu2+ and Cd2+ adsorption capacities in the three soil conditions increased with increasing equilibrium concentration. The adsorption capacities of Cu2+ and Cd2+ in farmland soils were higher than in woodland and grassland soils. The desorption of Cu2+ and Cd2+ in soil under different land use types increased with increasing adsorption of the ions. A positive linear correlation was noted between ion adsorption and desorption in different soil conditions. The absorbed Cu2+ and Cd2+ by soil was incompletely desorbed due to fixation of part heavy metals ions in soils. The amount of fixed exogenous heavy metal ions reflected the soil fixing capacity of the heavy metal ions. The fixing capacities of three soil conditions for the two heavy metal ions were non-identical. The fixed amounts of Cu2+ were 147.2 mg·kg-1, 118.5 mg·kg-1 and 61.9 mg·kg-1, and those of Cd2+ were 20.12 mg·kg-1, 33.33 mg·kg-1 and 9.97 mg·kg-1 in woodland, grassland and farmland conditions, respectively. The Langmuir equation and Freunlich adsorption equations were used to fit the Cu2+ and Cd2+ processes in different soil conditions. While the Cu2+ adsorption process was fitted using the Langmuir equation, that of Cd2+ was fitted using the Freunlich equation. Both Cu2+ and Cd2+ desorption in farmland soil were higher than those in woodland and grassland soils. The dynamic adsorptions of Cu2+ and Cd2+ in the three conditions showed a rapid reaction process. Also the adsorption reaction tended to balance out with time. The adsorption kinetics of heavy metals in the soils fitted well with the double constant equation and the Elovich equation. The adsorption of Cu2+ and Cd2+ in the three soils was related with soil clay content, organic matter content, pH and CEC. This was driven by surface soil adsorption force, properties of hydroxyl and carboxyl groups, soil surface charges, soil solution exchangeable ion concentrations, etc.
2013, 21(10): 1264-1270.
doi: 10.3724/SP.J.1011.2013.30267
Abstract:
To explore more promising ways improving the efficiency of phytoremediation of cadmium (Cd) contaminated soils, a pot culture experiment was conducted to study the impacts of accompanying anion fertilizer and chickpea intercropping on rape growth, Cd uptake and accumulation in soils containing 10.0 mg·kg 1. The results showed that in monoculture rape system, the order of soil DPTA extractable Cd content under different accompanying anion fertilizers was C1- > NO3- > SO42- > non-accompanying anion. Intercropping with chickpea increased soil DPTA extractable Cd content, and the effects were significant under accompanying anion fertilizers of C1- , NO3- and SO42- . In monoculture rape system, the order of rape taproot length under different accompanying anion fertilizers was NO3- > C1- > SO42- > non-accompanying anion, that of rape root volume was SO42- > NO3- > C1- > non-accompanying anion, it was NO3- > SO42- > C1- > non-accompanying anion for rape root activity. Intercropping with chickpea significantly increased rape taproot length and root volume under non-accompanying anion fertilizer, and increased root activity under non-accompanying anion fertilizer, and SO42- , NO3- accompanying fertilizers. In monoculture rape system, accompanying anions fertilizers significantly increased rape shoot Cd content, with C1- accompanying fertilizer presented highest Cd content (470.4 μg·plant-1). Intercropping with chickpea increased rape shoot Cd content, especially under C1- accompanying fertilizer, which reached 783.7 μg·plant-1. The transfer coefficient of Cd was increased under SO42- , NO3- accompanying fertilizers, and it was higher than 1 under all accompanying fertilizers in rape monoculture system. Intercropping with chickpea enhanced transfer coefficient under all accompanying fertilizers. Thus in using rape as phytoremediation plant, the application of C1- accompanying fertilizer with chickpea intercropping was a more effective measure for prompting remediation efficiency of Cd contaminated soils.
To explore more promising ways improving the efficiency of phytoremediation of cadmium (Cd) contaminated soils, a pot culture experiment was conducted to study the impacts of accompanying anion fertilizer and chickpea intercropping on rape growth, Cd uptake and accumulation in soils containing 10.0 mg·kg 1. The results showed that in monoculture rape system, the order of soil DPTA extractable Cd content under different accompanying anion fertilizers was C1- > NO3- > SO42- > non-accompanying anion. Intercropping with chickpea increased soil DPTA extractable Cd content, and the effects were significant under accompanying anion fertilizers of C1- , NO3- and SO42- . In monoculture rape system, the order of rape taproot length under different accompanying anion fertilizers was NO3- > C1- > SO42- > non-accompanying anion, that of rape root volume was SO42- > NO3- > C1- > non-accompanying anion, it was NO3- > SO42- > C1- > non-accompanying anion for rape root activity. Intercropping with chickpea significantly increased rape taproot length and root volume under non-accompanying anion fertilizer, and increased root activity under non-accompanying anion fertilizer, and SO42- , NO3- accompanying fertilizers. In monoculture rape system, accompanying anions fertilizers significantly increased rape shoot Cd content, with C1- accompanying fertilizer presented highest Cd content (470.4 μg·plant-1). Intercropping with chickpea increased rape shoot Cd content, especially under C1- accompanying fertilizer, which reached 783.7 μg·plant-1. The transfer coefficient of Cd was increased under SO42- , NO3- accompanying fertilizers, and it was higher than 1 under all accompanying fertilizers in rape monoculture system. Intercropping with chickpea enhanced transfer coefficient under all accompanying fertilizers. Thus in using rape as phytoremediation plant, the application of C1- accompanying fertilizer with chickpea intercropping was a more effective measure for prompting remediation efficiency of Cd contaminated soils.
2013, 21(10): 1271-1276.
doi: 10.3724/SP.J.1011.2013.30137
Abstract:
The production of biogas by anaerobic dry fermentation of straw could decrease environmental pollution from burning straw and at the same time produce abundant biogas residue that can be used as eco-organic fertilizer. However, the application of anaerobic dry fermentation of straw has been limited by the long processing cycle and slow rate of gas production. Hydrolysis has been identified as the factor slowing down straw fermentation, and carbohydrate hydrolase is a key element of hydrolysis. Biogas yield from the dry anaerobic fermentation of wheat straw was directly affected by hydrolase activity. Thus using wheat straw as the main component, carbohydrate hydrolase activities was studied during anaerobic dry fermentation under different temperature conditions in this study. The purpose of this study was to lay theoretical basis for increasing biogas production rate and shortening the residence time of straw fermentation through enzyme engineering. In the experiment, the fermentation materials were the mixture of wheat straw, inoculums and water with the proportion of 1∶7∶7. Total substance (TS) of the mixed materials was 35%. The experiment was carried out in wild-mouth bottle (as the fermentation container) and under different temperatures (20 ℃, 25 ℃, 30 ℃, 35 ℃ and 40 ℃) and with fermentation period of 35 days. The activities of cellulase, xylanase, amylase and sucrase were measured during the dry fermentation process of wheat straw mixture. The results showed that biogas production peaked at about 35 ℃. For the 20 40 ℃ temperature range, TS, volatilizable substance (VS) and carbon/nitrogen (C/N) ratio for the fermenting mixture decreased apparently with increasing temperature. With the end of fermentation, the pH of the fermenting materials in all the treatments declined under 7.0. The lowest pH was under the 40 ℃ condition. Cellulase activity was low during the initial period of fermentation while biogas production peaked later in the fermentation process. The rise in temperature was significantly enhanced cellulase activity. Initial xylanase activity was high, with a variation tendency of initial rise, a latter decline and a final smooth trend during the fermenting process. There were no obvious peaks for xylanase activity under the 20 25 ℃ during the fermentation process. Amylase activity was low at the initial stage and then rose rapidly afterwards, hitting peak values after about 10 days under temperatures of 30 ℃, 35 ℃ and 40 ℃. Sucrase activity tracked the same variation tend as amylase, except that sucrase activity rose more rapidly at temperatures above 30 ℃, declined more rapidly at 35 ℃ and then climaxed at 40 ℃ (which was on the 15th day of fermentation). This could been due to restrained microbial activity with substrate decline. In conclusion, the peak values of the four carbohydrate hydrolase enzymes activities were directly related with temperatures during the fermentation process. The peak value at 40 ℃ was higher than those at 30 ℃ and 35 ℃, apparently different from biogas production relationship with temperature. Biogas productions at 30 ℃ and 35 ℃ were higher than at 40 ℃. Hence temperature had different effects on different carbohydrate hydrolase activities during dry anaerobic fermentation.
The production of biogas by anaerobic dry fermentation of straw could decrease environmental pollution from burning straw and at the same time produce abundant biogas residue that can be used as eco-organic fertilizer. However, the application of anaerobic dry fermentation of straw has been limited by the long processing cycle and slow rate of gas production. Hydrolysis has been identified as the factor slowing down straw fermentation, and carbohydrate hydrolase is a key element of hydrolysis. Biogas yield from the dry anaerobic fermentation of wheat straw was directly affected by hydrolase activity. Thus using wheat straw as the main component, carbohydrate hydrolase activities was studied during anaerobic dry fermentation under different temperature conditions in this study. The purpose of this study was to lay theoretical basis for increasing biogas production rate and shortening the residence time of straw fermentation through enzyme engineering. In the experiment, the fermentation materials were the mixture of wheat straw, inoculums and water with the proportion of 1∶7∶7. Total substance (TS) of the mixed materials was 35%. The experiment was carried out in wild-mouth bottle (as the fermentation container) and under different temperatures (20 ℃, 25 ℃, 30 ℃, 35 ℃ and 40 ℃) and with fermentation period of 35 days. The activities of cellulase, xylanase, amylase and sucrase were measured during the dry fermentation process of wheat straw mixture. The results showed that biogas production peaked at about 35 ℃. For the 20 40 ℃ temperature range, TS, volatilizable substance (VS) and carbon/nitrogen (C/N) ratio for the fermenting mixture decreased apparently with increasing temperature. With the end of fermentation, the pH of the fermenting materials in all the treatments declined under 7.0. The lowest pH was under the 40 ℃ condition. Cellulase activity was low during the initial period of fermentation while biogas production peaked later in the fermentation process. The rise in temperature was significantly enhanced cellulase activity. Initial xylanase activity was high, with a variation tendency of initial rise, a latter decline and a final smooth trend during the fermenting process. There were no obvious peaks for xylanase activity under the 20 25 ℃ during the fermentation process. Amylase activity was low at the initial stage and then rose rapidly afterwards, hitting peak values after about 10 days under temperatures of 30 ℃, 35 ℃ and 40 ℃. Sucrase activity tracked the same variation tend as amylase, except that sucrase activity rose more rapidly at temperatures above 30 ℃, declined more rapidly at 35 ℃ and then climaxed at 40 ℃ (which was on the 15th day of fermentation). This could been due to restrained microbial activity with substrate decline. In conclusion, the peak values of the four carbohydrate hydrolase enzymes activities were directly related with temperatures during the fermentation process. The peak value at 40 ℃ was higher than those at 30 ℃ and 35 ℃, apparently different from biogas production relationship with temperature. Biogas productions at 30 ℃ and 35 ℃ were higher than at 40 ℃. Hence temperature had different effects on different carbohydrate hydrolase activities during dry anaerobic fermentation.
2013, 21(10): 1277-1283.
doi: 10.3724/SP.J.1011.2013.30128
Abstract:
Bacillus thuringiensis (Bt) is a gram-positive and soil-dwelling bacterium widely used as biological pesticide with broad insecticidal spectra. Most Bt strains can produce Cry proteins which have specific activities against insect species of the orders Lepidoptera, Diptera, Coleoptera, Hymenoptera and Nematodes. Because of the specificity against target insects, Bt has been regarded as an environmentally friendly biopesticide with little or no effect on mammals, birds, amphibians, reptiles and most other beneficial insects. In fact, it has so far not been conclusively studied whether Bt was really safe to natural microbial communities in agricultural ecosystems. In this study, the influence of Bt on soil bacterial population and diversity in cotton fields was investigated by using traditional plating method and PCR-DGGE technique after application of two dosages [0.1 kg·hm-2 (recommended dosage) and 10 kg·hm-2 (hgih dosage)] of Bt agent. Avermectins and water were respectively used as positive and negative controls. Result indicated that 3 days after treatment, Bt had no significant effect on bacterial abundance in soils. Bacterial abundance reached the maximum 3 days after treatment and began to decline thereafter. Then 12 days after treatment, bacterial abundance in soils treated with water, commercial recommended dosage and high dosage Bt was 4.0×107 CFU·g-1. Bacterial abundance in soils treated with recommended dosage Bt was not significantly different from that treated with water. Sixth days into the experiment, there was a significantly high bacterial abundance in soils treated with recommended dosage Bt. There was also no significant difference in soil bacterial abundance between high dosage Bt and water during the whole experiment. Six days after treatment, bacterial abundance of soil treated with avermectins was not significantly different from that treated with water. However, bacterial abundance of avermectins treatment was significantly lower than that of the other 3 treatments 12 45 days after treatment. DGGE spectrogram analyses showed that Bt agent had no significant harmful effects on cotton rhizosphere soil bacterial community structures. Based on analyses of bacterial structures of different treatments, electrophoresis bands of samples treated with given dosages Bt and negative control were in the same branch cluster after 12 days of treatment. This indicated that Bt agent had no influence on bacterial community structure after 12 days. The diversity indexes of Bt treatments were same as that of negative control. Compared with Bt agent, avermectins significantly suppressed bacterial abundance in cotton rhizosphere soils. Following DGGE analysis, 17 different sequences (B1 B17) retrieved from the GenBank using BLAST program were isolated. Sequences with 100% homology of Bt were observed only in Bt treatment dosages of 10 kg·hm-2. This suggested that Bt could not replace native species in agricultural ecosystems if applied at commercial recommended dosage. In addition, beneficial-role bacteria in soils (e.g., Bradyrhizobium sp. which helped Leguminosae to fix nitrogen into soils; Sphingobium sp., Sphingomonas sp. and Rhodococcus sp. which acted as pollution remediation species) were retrieved from the GenBank. Bt had no influence on these functional species in soils at the given dosages. In conclusion, the study provided an evaluation of the effects of Bt on microbial population and community structure using culture-dependent/independent techniques. The study suggested that Bt biocontrol agent was environmentally friendly with no significant effect on natural bacterial communities in soil ecologies.
Bacillus thuringiensis (Bt) is a gram-positive and soil-dwelling bacterium widely used as biological pesticide with broad insecticidal spectra. Most Bt strains can produce Cry proteins which have specific activities against insect species of the orders Lepidoptera, Diptera, Coleoptera, Hymenoptera and Nematodes. Because of the specificity against target insects, Bt has been regarded as an environmentally friendly biopesticide with little or no effect on mammals, birds, amphibians, reptiles and most other beneficial insects. In fact, it has so far not been conclusively studied whether Bt was really safe to natural microbial communities in agricultural ecosystems. In this study, the influence of Bt on soil bacterial population and diversity in cotton fields was investigated by using traditional plating method and PCR-DGGE technique after application of two dosages [0.1 kg·hm-2 (recommended dosage) and 10 kg·hm-2 (hgih dosage)] of Bt agent. Avermectins and water were respectively used as positive and negative controls. Result indicated that 3 days after treatment, Bt had no significant effect on bacterial abundance in soils. Bacterial abundance reached the maximum 3 days after treatment and began to decline thereafter. Then 12 days after treatment, bacterial abundance in soils treated with water, commercial recommended dosage and high dosage Bt was 4.0×107 CFU·g-1. Bacterial abundance in soils treated with recommended dosage Bt was not significantly different from that treated with water. Sixth days into the experiment, there was a significantly high bacterial abundance in soils treated with recommended dosage Bt. There was also no significant difference in soil bacterial abundance between high dosage Bt and water during the whole experiment. Six days after treatment, bacterial abundance of soil treated with avermectins was not significantly different from that treated with water. However, bacterial abundance of avermectins treatment was significantly lower than that of the other 3 treatments 12 45 days after treatment. DGGE spectrogram analyses showed that Bt agent had no significant harmful effects on cotton rhizosphere soil bacterial community structures. Based on analyses of bacterial structures of different treatments, electrophoresis bands of samples treated with given dosages Bt and negative control were in the same branch cluster after 12 days of treatment. This indicated that Bt agent had no influence on bacterial community structure after 12 days. The diversity indexes of Bt treatments were same as that of negative control. Compared with Bt agent, avermectins significantly suppressed bacterial abundance in cotton rhizosphere soils. Following DGGE analysis, 17 different sequences (B1 B17) retrieved from the GenBank using BLAST program were isolated. Sequences with 100% homology of Bt were observed only in Bt treatment dosages of 10 kg·hm-2. This suggested that Bt could not replace native species in agricultural ecosystems if applied at commercial recommended dosage. In addition, beneficial-role bacteria in soils (e.g., Bradyrhizobium sp. which helped Leguminosae to fix nitrogen into soils; Sphingobium sp., Sphingomonas sp. and Rhodococcus sp. which acted as pollution remediation species) were retrieved from the GenBank. Bt had no influence on these functional species in soils at the given dosages. In conclusion, the study provided an evaluation of the effects of Bt on microbial population and community structure using culture-dependent/independent techniques. The study suggested that Bt biocontrol agent was environmentally friendly with no significant effect on natural bacterial communities in soil ecologies.
2013, 21(10): 1284-1292.
doi: 10.3724/SP.J.1011.2013.30183
Abstract:
Terrain significantly influences land use change and spatial pattern. Compared with the single terrain factor (elevation, slope) method, terrain niche index, combination of elevation and slope, can reflect detailed spatial variability of terrains. Distribution index can describe the differences between actual and standard distribution of different land use types, excluding the disturbances of the area. The comprehensive index of land use degree can reflect regional land use intensity and is suitable for comprehensive evaluation of land use degree. Taking advantage of GIS spatial capabilities along with terrain niche index, distribution index and comprehensive index of land use degree, this study analyzed land use patterns and changes in Taihang Mountain in Hebei Province from 1990 to 2008. Also the land use degree on terrain gradient was quantitatively analyzed and terrain influence on land use selection pattern was explored. The results showed that the spatial distributions and changes in various land use types were considerably influenced by terrain factors. Arable land, construction land, water and unused land were mainly in areas with 0° 15° slope and <500 m altitude. Also the changing areas of land use on these terrains were highest. Arable land, construction land, water and unused land were mainly in areas with low terrain niche index. Then grassland was mainly in areas with medium terrain niche index and woodland in areas with medium-to-high terrain niche index. With increasing terrain niche index, the distribution index of arable land decreased, that of grassland, construction land, water and unused land decreased followed by an increase, while that of woodland increased. From 1990 to 2008, predominant distribution terrain niche index scale of woodland increased by two units. That of grassland expanded by three units in the middle terrain niche section but reduced the sections with high terrain niche. That of water expanded in low terrain niche section, and that of unused lands reduced significantly. Then those of arable land and construction land generally remained stable during the study period. Additionally, the comprehensive index of land use degree reduced with increasing terrain niche index. Based on quantitative analysis of the land use degree on terrain gradients, terrain niche was divided into three sections. They were dominant terrain niche section of arable land, water, construction land and unused land; dominant terrain niche sections of grassland and woodland; and dominant terrain niche section of woodland. The areas of the three sections were 45.79%, 41.30% and 12.91% of the study area. Finally, suggestions were put forward for rational use of land resources and ecological environment restoration in Taihang Mountain in Hebei Province.
Terrain significantly influences land use change and spatial pattern. Compared with the single terrain factor (elevation, slope) method, terrain niche index, combination of elevation and slope, can reflect detailed spatial variability of terrains. Distribution index can describe the differences between actual and standard distribution of different land use types, excluding the disturbances of the area. The comprehensive index of land use degree can reflect regional land use intensity and is suitable for comprehensive evaluation of land use degree. Taking advantage of GIS spatial capabilities along with terrain niche index, distribution index and comprehensive index of land use degree, this study analyzed land use patterns and changes in Taihang Mountain in Hebei Province from 1990 to 2008. Also the land use degree on terrain gradient was quantitatively analyzed and terrain influence on land use selection pattern was explored. The results showed that the spatial distributions and changes in various land use types were considerably influenced by terrain factors. Arable land, construction land, water and unused land were mainly in areas with 0° 15° slope and <500 m altitude. Also the changing areas of land use on these terrains were highest. Arable land, construction land, water and unused land were mainly in areas with low terrain niche index. Then grassland was mainly in areas with medium terrain niche index and woodland in areas with medium-to-high terrain niche index. With increasing terrain niche index, the distribution index of arable land decreased, that of grassland, construction land, water and unused land decreased followed by an increase, while that of woodland increased. From 1990 to 2008, predominant distribution terrain niche index scale of woodland increased by two units. That of grassland expanded by three units in the middle terrain niche section but reduced the sections with high terrain niche. That of water expanded in low terrain niche section, and that of unused lands reduced significantly. Then those of arable land and construction land generally remained stable during the study period. Additionally, the comprehensive index of land use degree reduced with increasing terrain niche index. Based on quantitative analysis of the land use degree on terrain gradients, terrain niche was divided into three sections. They were dominant terrain niche section of arable land, water, construction land and unused land; dominant terrain niche sections of grassland and woodland; and dominant terrain niche section of woodland. The areas of the three sections were 45.79%, 41.30% and 12.91% of the study area. Finally, suggestions were put forward for rational use of land resources and ecological environment restoration in Taihang Mountain in Hebei Province.
2013, 21(10): 1293-1298.
doi: 10.3724/SP.J.1011.2013.30043
Abstract:
The evaluation of social benefits is an important component of land remediation. Evaluation results of land reclamation project areas lay the crucial basis for evaluating the social benefits of land regulation. Therefore conducting research on land reclamation and social valuation is of tremendous practical significance. A case-study in land rehabilitation project area in Quyang County of Hebei Province was conducted in this research. The social value of cultivated land in the project area was evaluated through constructing a cultivated land value evaluation system based on land reclamation projects and research methods in resource economics, including market value method, alternative market method, achievement reference methods and capital reduction method. In addition, changes and differences in values before and after reclamation were analyzed and conclusions drawn. The results indicated that after land reclamation, the social security value increased by 324.420 2 million RMB. However, the percentage of total value decreased compared with the ratio before the land reclamation. Social stability value increased by 14.532 9 million RMB. Then cultural landscape value increased by 8.843 7 million RMB and both proportions were enhanced. Total social value of cultivated land increased by 347.796 8 million RMB. Land reclamation social benefit was remarkable not only for convenient cultivation conditions and increased cultivated area, but also for enhanced ecology landscape value. This study provided a significant reference for the evaluation of social values of land reclamation. The results also provided the scientific basis for social benefit evaluation of land remediation in Quyang County.
The evaluation of social benefits is an important component of land remediation. Evaluation results of land reclamation project areas lay the crucial basis for evaluating the social benefits of land regulation. Therefore conducting research on land reclamation and social valuation is of tremendous practical significance. A case-study in land rehabilitation project area in Quyang County of Hebei Province was conducted in this research. The social value of cultivated land in the project area was evaluated through constructing a cultivated land value evaluation system based on land reclamation projects and research methods in resource economics, including market value method, alternative market method, achievement reference methods and capital reduction method. In addition, changes and differences in values before and after reclamation were analyzed and conclusions drawn. The results indicated that after land reclamation, the social security value increased by 324.420 2 million RMB. However, the percentage of total value decreased compared with the ratio before the land reclamation. Social stability value increased by 14.532 9 million RMB. Then cultural landscape value increased by 8.843 7 million RMB and both proportions were enhanced. Total social value of cultivated land increased by 347.796 8 million RMB. Land reclamation social benefit was remarkable not only for convenient cultivation conditions and increased cultivated area, but also for enhanced ecology landscape value. This study provided a significant reference for the evaluation of social values of land reclamation. The results also provided the scientific basis for social benefit evaluation of land remediation in Quyang County.
2013, 21(10)
doi: 10.3724/SP.J.1011.2013.30343
Abstract:
The study of virtual water is critical for the security of water resources and livestock products. To explore regional virtual water flow compatibility, improve allocation of water resources in China and optimize livestock product spatial layout, we built a rationality index system to assess the suitability of virtual water flow in agricultural and livestock products in China. The assessment system involved water resources, land resources, basis for agricultural development, social economic development and ecological environment. The system was then used to determine the suitability of virtual water flow in agricultural and livestock products in a comprehensive weight summation analysis. Based on present conditions of virtual water flow in agricultural and livestock products, we put forward the concept of rationality of virtual water flow in agricultural and livestock products and built a quantitative evaluation model for determining rationality index of virtual water flow in agricultural and livestock products across the provinces in China. The results showed that provinces suitable for virtual water output exceeded that suitable for virtual water input in agricultural and livestock products. Most provinces suitable for virtual water output were the inland provinces of China. In Tibet Autonomous Region, Heilongjiang Province, and Inner Mongolia Autonomous Region, agricultural and livestock products suitability index of virtual water output was high. The top three suitability indexes of virtual water output in agricultural and livestock products were for Beijing City, Tianjin City and Shanghai City. The factors that affected the suitability of virtual water flow in agricultural and livestock products varied vastly among provinces. Although the total rationality index of virtual water flow in agricultural and livestock products in the provinces in China was not high, only 14 provinces had rationality index lower than 1. The rationality indexes for Shanghai City (0.16), Shanxi Province (0.21) and Jilin Province (0.23) were suitable in terms of virtual water flow in agricultural and livestock products. Guizhou Province was most irrational with an index value of 4.84. The next most irrational zones were Henan Province (4.18) and Ningxia Hui Autonomous Region (4.04). There was no obvious regional distribution pattern of rationality index. Based on the current state and suitability of virtual water flow in agricultural and livestock products in the provinces, six classes of adjustments were recommended. The classes of adjustments included controlling output, encouraging output, controlling input, encouraging input, converting to input and converting to output. Six provinces belonged to controlling output - Ningxia Hui Autonomous Region, Inner Mongolia Autonomous Region, Xinjiang Uygur Autonomous Region, Helongjiang Province, Henan Province and Jilin Province. While Tibet Autonomous Region, Qinghai Province and Anhui Province needed to increase virtual water output, Fujian Province, Zhejiang Province, Chongqing City and Guangzhou Province needed to reduce it. The present level of virtual water input was lower than that of virtual water input suitability in six provinces - Beijing City, Shanghai City, Tianjin City, Shanxi Province, Jiangsu Province and Shaanxi Province. It therefore was suggested that all relevant stakeholders put more efforts in increasing virtual water input in these cities.
The study of virtual water is critical for the security of water resources and livestock products. To explore regional virtual water flow compatibility, improve allocation of water resources in China and optimize livestock product spatial layout, we built a rationality index system to assess the suitability of virtual water flow in agricultural and livestock products in China. The assessment system involved water resources, land resources, basis for agricultural development, social economic development and ecological environment. The system was then used to determine the suitability of virtual water flow in agricultural and livestock products in a comprehensive weight summation analysis. Based on present conditions of virtual water flow in agricultural and livestock products, we put forward the concept of rationality of virtual water flow in agricultural and livestock products and built a quantitative evaluation model for determining rationality index of virtual water flow in agricultural and livestock products across the provinces in China. The results showed that provinces suitable for virtual water output exceeded that suitable for virtual water input in agricultural and livestock products. Most provinces suitable for virtual water output were the inland provinces of China. In Tibet Autonomous Region, Heilongjiang Province, and Inner Mongolia Autonomous Region, agricultural and livestock products suitability index of virtual water output was high. The top three suitability indexes of virtual water output in agricultural and livestock products were for Beijing City, Tianjin City and Shanghai City. The factors that affected the suitability of virtual water flow in agricultural and livestock products varied vastly among provinces. Although the total rationality index of virtual water flow in agricultural and livestock products in the provinces in China was not high, only 14 provinces had rationality index lower than 1. The rationality indexes for Shanghai City (0.16), Shanxi Province (0.21) and Jilin Province (0.23) were suitable in terms of virtual water flow in agricultural and livestock products. Guizhou Province was most irrational with an index value of 4.84. The next most irrational zones were Henan Province (4.18) and Ningxia Hui Autonomous Region (4.04). There was no obvious regional distribution pattern of rationality index. Based on the current state and suitability of virtual water flow in agricultural and livestock products in the provinces, six classes of adjustments were recommended. The classes of adjustments included controlling output, encouraging output, controlling input, encouraging input, converting to input and converting to output. Six provinces belonged to controlling output - Ningxia Hui Autonomous Region, Inner Mongolia Autonomous Region, Xinjiang Uygur Autonomous Region, Helongjiang Province, Henan Province and Jilin Province. While Tibet Autonomous Region, Qinghai Province and Anhui Province needed to increase virtual water output, Fujian Province, Zhejiang Province, Chongqing City and Guangzhou Province needed to reduce it. The present level of virtual water input was lower than that of virtual water input suitability in six provinces - Beijing City, Shanghai City, Tianjin City, Shanxi Province, Jiangsu Province and Shaanxi Province. It therefore was suggested that all relevant stakeholders put more efforts in increasing virtual water input in these cities.
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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