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Measurement, spatial spillover and influencing factors of agricultural carbon emissions efficiency in China
WU Haoyue, HUANG Hanjiao, HE Yu, CHEN Wenkuan
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Effects of tillage and straw returning method on the distribution of carbon and nitrogen in soil aggregates
ZHANG Yuming, HU Chunsheng, CHEN Suying, WANG Yuying, LI Xiaoxin, DONG Wenxu, LIU Xiuping, PEI Lin, ZHANG Hui
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Relationship between policy incentives, ecological cognition, and organic fertilizer application by farmers: Based on a moderated mediation model
SANG Xiance, LUO Xiaofeng, HUANG Yanzhong, TANG Lin
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Spatio-temporal evolution of carbon stocks in the Yellow River Basin based on InVEST and CA-Markov models
YANG Jie, XIE Baopeng, ZHANG Degang
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Effects of straw returning and fertilization on soil bacterial and fungal community structures and diversities in rice-wheat rotation soil
ZHANG Hanlin, BAI Naling, ZHENG Xianqing, LI Shuangxi, ZHANG Juanqin, ZHANG Haiyun, ZHOU Sheng, SUN Huifeng, LYU Weiguang
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2016 Vol. 24, No. 4
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2016, 24(4): 403-415.
Abstract:
Intercropping is one of the traditional farming systems practiced by farmers in China for more than 2 000 years with some intriguing ecological principles. Previous studies have shown that intercropping enhanced not only crop productivity, but also the utilization efficiencies of resources, including above-ground (e.g., land, thermal, radiation and space) and below-ground (e.g., water and nutrients) resources. Recent efforts have made some progresses on intercropping research. Here, we reviewed the potential of intercropping to strength ecosystem services and functions at the agroecosystem level, prospective research directions and highlight practical uses in modern agriculture. Intercropping increased biodiversity, productivity and stability of agroecosystems. At the same time, intercropping enhanced water use by isolating the time for maximum water requirements of one species from the other, and spatial complementarity by hydraulic lift of water. The enhancement of nitrogen acquisition was attributed to niche differentiation of N resources in which cereals acquired more mineral N from the soil, while legumes fixed more N from air N2. This was because that cereals was more competitive than legumes and mineral N competition increased symbiotic N2 fixation of legumes. Some P mobilized species facilitated the conversion of soil unavailable P into available P, which benefited not only the species but also the neighboring immobilized other species. E.g., the roots of faba bean released carboxylates or proton to dissolve sparingly soluble P in soils. Also the roots of chickpea released phytase or phosphatase to decompose organic P in the soil, which increased available soil P. There were interspecific facilitations of iron (Fe) and zinc (Zn) nutrients in intercropping of dicotyledonous or non-graminaceous monocotyledonous (strategy I for Fe acquisition and non-Fe or Zn mobilization) species and graminaceous monocotyledonous (strategy Ⅱ for Fe acquisition and Fe or Zn mobilization) species, which benefited micronutrient availability in intercropped non-Fe-mobilizing or Zn-mobilizing species. In the paper, I also identified some important future directions of intercropping research and practical uses. The research directions include crop diversity and agricultural sustainability, signal-controlled interspecific interactions between intercropped species, linkage interactions to above-ground and below-ground diversities, functional, structural and empirical models for intercropping, etc. In application, intercropping can be used to develop ecologically intensive agriculture and organic farming, to enhance fertilizer recovery, and to enrich the contents of microelements in edible parts of crops. Finally, it will be useful to further develop suitable machinery and breed newer crop varieties for intercropping.
Intercropping is one of the traditional farming systems practiced by farmers in China for more than 2 000 years with some intriguing ecological principles. Previous studies have shown that intercropping enhanced not only crop productivity, but also the utilization efficiencies of resources, including above-ground (e.g., land, thermal, radiation and space) and below-ground (e.g., water and nutrients) resources. Recent efforts have made some progresses on intercropping research. Here, we reviewed the potential of intercropping to strength ecosystem services and functions at the agroecosystem level, prospective research directions and highlight practical uses in modern agriculture. Intercropping increased biodiversity, productivity and stability of agroecosystems. At the same time, intercropping enhanced water use by isolating the time for maximum water requirements of one species from the other, and spatial complementarity by hydraulic lift of water. The enhancement of nitrogen acquisition was attributed to niche differentiation of N resources in which cereals acquired more mineral N from the soil, while legumes fixed more N from air N2. This was because that cereals was more competitive than legumes and mineral N competition increased symbiotic N2 fixation of legumes. Some P mobilized species facilitated the conversion of soil unavailable P into available P, which benefited not only the species but also the neighboring immobilized other species. E.g., the roots of faba bean released carboxylates or proton to dissolve sparingly soluble P in soils. Also the roots of chickpea released phytase or phosphatase to decompose organic P in the soil, which increased available soil P. There were interspecific facilitations of iron (Fe) and zinc (Zn) nutrients in intercropping of dicotyledonous or non-graminaceous monocotyledonous (strategy I for Fe acquisition and non-Fe or Zn mobilization) species and graminaceous monocotyledonous (strategy Ⅱ for Fe acquisition and Fe or Zn mobilization) species, which benefited micronutrient availability in intercropped non-Fe-mobilizing or Zn-mobilizing species. In the paper, I also identified some important future directions of intercropping research and practical uses. The research directions include crop diversity and agricultural sustainability, signal-controlled interspecific interactions between intercropped species, linkage interactions to above-ground and below-ground diversities, functional, structural and empirical models for intercropping, etc. In application, intercropping can be used to develop ecologically intensive agriculture and organic farming, to enhance fertilizer recovery, and to enrich the contents of microelements in edible parts of crops. Finally, it will be useful to further develop suitable machinery and breed newer crop varieties for intercropping.
2016, 24(4): 416-434.
Abstract:
Responses and feedbacks of soil microorganism to fertilization areis important to the evaluation of fertilization effect and establishment of scientific fertilization management. The paper summarized the research results of author’s team in effect of long-term fertilizations, especially single application of organic fertilizer, on soil microorganisms related to the carbon, nitrogen and phosphorus cycling in fluvo-aquic soil. The microbial mechanisms of soil fertility enhancement were also discussed in the paper. The results indicated that for the fluvo-aquic soil in the North China Plain, long term balanced fertilization, especially long term organic fertilization, increased soil contents of organic carbon and other nutrients, the effect was more obvious on soil phosphorus content. This, furthermore, improved soil microorganism community structure, and enhanced soil microbial biomass carbon content, invertase activity, respiration rate and microbial function diversity (carbon metabolic activity), while significantly decreased metabolic quotient and metabolic heat of soil microorganisms. On the contrary, nutritional deficiency, especially phosphorus deficiency, not only decreased metabolic efficiency, but also induced more heat dissipation and CO2 emission during metabolism of soil microorganisms, which finally decreased soil quality. Long-term application of nitrogen fertilizer enforced soil nitrification activity, and increased amount and diversity of ammonia oxidizing bacteria. Inorganic nitrogen fertilizer was more effective than organic nitrogen fertilizer. In phosphorus-deficient fluvo-aquic soil, rational phosphorus fertilization was essential precondition of scientific application of nitrogen fertilization to promote crop growth and soil fertility, reduce nitrogen loss. Long-term application of phosphorus fertilizer, and balanced fertilization lowered the dependence of crop growth on arbuscular mycorrhizal fungi (AMF), decreased soil AMF diversity and induced differentiation of AMF, which benefited the sustainability of phosphorus-deficient fluvo-aquic soil. An indigenous microorganism of fluvo-aquic soil, Bacillus asahii with unique physiological characteristics and abundant metabolic diversity significantly responded to long-term organic fertilization, and could develop to the dominant species during two to four years. B. asahii could accelerated other microorganisms in the process of organic matter accumulation and phosphorus recycle in fluvo-aquic soil, played a leading role on crop growth and soil fertility increase. The result was favored for understanding the microbial mechanism of effect of long-term organic fertilization on soil fertility improvement in the North China Plain, and for adjusting soil microorganism to serve farmland ecosystem.
Responses and feedbacks of soil microorganism to fertilization areis important to the evaluation of fertilization effect and establishment of scientific fertilization management. The paper summarized the research results of author’s team in effect of long-term fertilizations, especially single application of organic fertilizer, on soil microorganisms related to the carbon, nitrogen and phosphorus cycling in fluvo-aquic soil. The microbial mechanisms of soil fertility enhancement were also discussed in the paper. The results indicated that for the fluvo-aquic soil in the North China Plain, long term balanced fertilization, especially long term organic fertilization, increased soil contents of organic carbon and other nutrients, the effect was more obvious on soil phosphorus content. This, furthermore, improved soil microorganism community structure, and enhanced soil microbial biomass carbon content, invertase activity, respiration rate and microbial function diversity (carbon metabolic activity), while significantly decreased metabolic quotient and metabolic heat of soil microorganisms. On the contrary, nutritional deficiency, especially phosphorus deficiency, not only decreased metabolic efficiency, but also induced more heat dissipation and CO2 emission during metabolism of soil microorganisms, which finally decreased soil quality. Long-term application of nitrogen fertilizer enforced soil nitrification activity, and increased amount and diversity of ammonia oxidizing bacteria. Inorganic nitrogen fertilizer was more effective than organic nitrogen fertilizer. In phosphorus-deficient fluvo-aquic soil, rational phosphorus fertilization was essential precondition of scientific application of nitrogen fertilization to promote crop growth and soil fertility, reduce nitrogen loss. Long-term application of phosphorus fertilizer, and balanced fertilization lowered the dependence of crop growth on arbuscular mycorrhizal fungi (AMF), decreased soil AMF diversity and induced differentiation of AMF, which benefited the sustainability of phosphorus-deficient fluvo-aquic soil. An indigenous microorganism of fluvo-aquic soil, Bacillus asahii with unique physiological characteristics and abundant metabolic diversity significantly responded to long-term organic fertilization, and could develop to the dominant species during two to four years. B. asahii could accelerated other microorganisms in the process of organic matter accumulation and phosphorus recycle in fluvo-aquic soil, played a leading role on crop growth and soil fertility increase. The result was favored for understanding the microbial mechanism of effect of long-term organic fertilization on soil fertility improvement in the North China Plain, and for adjusting soil microorganism to serve farmland ecosystem.
2016, 24(4): 435-442.
Abstract:
The history of diversified cropping can be dated back to the era of man’s evolution that followed hunting and gathering, and this form of cropping has stood the test of times to be still as an important farming practice in modern agriculture. In recent years, to control insect pests using diversified cropping has been the focus of agricultural research. Diversified cropping has direct effect on the occurrences, damages and behaviors of insect pests. Many researches have indicated that diversified cropping reduces, to a large extent, the occurrences and damages of insect pests. It has been noted in some cases, however, that diversified cropping systems fail to reduce or even increase insect pest damages to crops. Diversified cropping affects not only natural enemy populations, but also parasitic and predation rates of the populations. Diversified cropping also influences natural enemies by disturbing the orientation, foraging and dispersal behaviors of the enemies. This study summarized the effects of diversified cropping on insect pests and natural enemies in agroecosystems. From a review of domestic and international research reports, the study also highlighted current problems and future researches on diversified cropping systems. Seven hypotheses (physical obstruction, visual camouflage, host plant odor masking, using repellent chemicals, altering host plant odor profiles, enemy hypothesis and resource concentration hypothesis) and one theory (appropriate/inappropriate landing) were introduced regarding the relationship between diversified cropping and insect pests. The hypothesis and theory largely explained the relationship, but none of them was fully elucidated the mechanisms of the effects of diversified cropping on insect pests and natural enemies in agroecosystems.
The history of diversified cropping can be dated back to the era of man’s evolution that followed hunting and gathering, and this form of cropping has stood the test of times to be still as an important farming practice in modern agriculture. In recent years, to control insect pests using diversified cropping has been the focus of agricultural research. Diversified cropping has direct effect on the occurrences, damages and behaviors of insect pests. Many researches have indicated that diversified cropping reduces, to a large extent, the occurrences and damages of insect pests. It has been noted in some cases, however, that diversified cropping systems fail to reduce or even increase insect pest damages to crops. Diversified cropping affects not only natural enemy populations, but also parasitic and predation rates of the populations. Diversified cropping also influences natural enemies by disturbing the orientation, foraging and dispersal behaviors of the enemies. This study summarized the effects of diversified cropping on insect pests and natural enemies in agroecosystems. From a review of domestic and international research reports, the study also highlighted current problems and future researches on diversified cropping systems. Seven hypotheses (physical obstruction, visual camouflage, host plant odor masking, using repellent chemicals, altering host plant odor profiles, enemy hypothesis and resource concentration hypothesis) and one theory (appropriate/inappropriate landing) were introduced regarding the relationship between diversified cropping and insect pests. The hypothesis and theory largely explained the relationship, but none of them was fully elucidated the mechanisms of the effects of diversified cropping on insect pests and natural enemies in agroecosystems.
2016, 24(4): 443-450.
Abstract:
It is undoubted that biodiversity and its’ ecosystem services have significant importance for agricultural landscape. The semi-natural habitats are the indispensable covers in agro-landscape, which maintain higher biodiversity because they provide refuge, foods, breeding place. To meet the demands of a growing human population, agricultural systems have been enlarged by altering non-crop habitats area to crop land and produced more crops per unit area, the disturbance to ecosystem intensified inducing decreasing of biodiversity. Keeping high biodiversity in agricultural landscape is significant for sustainable development of agriculture. In this paper, composition and characteristics of agricultural landscape heterogeneity were reviewed and its effects on biodiversity and ecological service discussed. Landscape heterogeneity included compositional heterogeneity, configurational heterogeneity, as well as temporal heterogeneity and functional heterogeneity. Most evidences showed that higher heterogeneity of agro-landscape affected positively on biodiversity. The temporal dynamics (historical, short-term and seasonal change of landscape) of landscape context may help improving understanding about the interaction between landscape structure and biodiversity in agro-landscape. Scale effect of landscape heterogeneity on biodiversity existed and is a core content of landscape ecology. Multi-scale effects of spatial and temporal landscape heterogeneity on non-agricultural biodiversity were significant. The biodiversity of plants, ground arthropod, and soil fauna were related to landscape heterogeneity in different radius buffer area. The responses of different non-agricultural biological groups were different because the landscape context and biological characteristics. The mechanisms of landscape heterogeneity maintaining biodiversity was also summarized. The combination of plant dispersal modes (e.g. wind, animals, vegetative) or / animals migration modes (e.g. crawling, jumping, flying) and landscape structure (e.g. connectivity of semi-natural habitat, presence of dense non-crop habitats) determined how far plant and animal species could move through the landscape to reach suitable patches. Influences of landscape heterogeneity on bio-control, pollination, and material cycle that provided by natural enemy, flower visitors and soil fauna were overviewed too. More and more studies had shown landscape heterogeneity and agricultural managements were important driving factors of plant, animal, and microorganisms, and furthermore impacted ecosystem services, such as nutrient recycle, water adjustment, pest biocontrol, etc. Based on the results of a series study of effects of agricultural landscape heterogeneity on non-agricultural biodiversity in the middle and lower area of the Yellow River, the development and perspective of landscape heterogeneity and biodiversity were summarized. The further studies should focus on relationships between agro-landscape context and biodiversity and its mechanisms based on spato-temporal heterogeneity of landscape.
It is undoubted that biodiversity and its’ ecosystem services have significant importance for agricultural landscape. The semi-natural habitats are the indispensable covers in agro-landscape, which maintain higher biodiversity because they provide refuge, foods, breeding place. To meet the demands of a growing human population, agricultural systems have been enlarged by altering non-crop habitats area to crop land and produced more crops per unit area, the disturbance to ecosystem intensified inducing decreasing of biodiversity. Keeping high biodiversity in agricultural landscape is significant for sustainable development of agriculture. In this paper, composition and characteristics of agricultural landscape heterogeneity were reviewed and its effects on biodiversity and ecological service discussed. Landscape heterogeneity included compositional heterogeneity, configurational heterogeneity, as well as temporal heterogeneity and functional heterogeneity. Most evidences showed that higher heterogeneity of agro-landscape affected positively on biodiversity. The temporal dynamics (historical, short-term and seasonal change of landscape) of landscape context may help improving understanding about the interaction between landscape structure and biodiversity in agro-landscape. Scale effect of landscape heterogeneity on biodiversity existed and is a core content of landscape ecology. Multi-scale effects of spatial and temporal landscape heterogeneity on non-agricultural biodiversity were significant. The biodiversity of plants, ground arthropod, and soil fauna were related to landscape heterogeneity in different radius buffer area. The responses of different non-agricultural biological groups were different because the landscape context and biological characteristics. The mechanisms of landscape heterogeneity maintaining biodiversity was also summarized. The combination of plant dispersal modes (e.g. wind, animals, vegetative) or / animals migration modes (e.g. crawling, jumping, flying) and landscape structure (e.g. connectivity of semi-natural habitat, presence of dense non-crop habitats) determined how far plant and animal species could move through the landscape to reach suitable patches. Influences of landscape heterogeneity on bio-control, pollination, and material cycle that provided by natural enemy, flower visitors and soil fauna were overviewed too. More and more studies had shown landscape heterogeneity and agricultural managements were important driving factors of plant, animal, and microorganisms, and furthermore impacted ecosystem services, such as nutrient recycle, water adjustment, pest biocontrol, etc. Based on the results of a series study of effects of agricultural landscape heterogeneity on non-agricultural biodiversity in the middle and lower area of the Yellow River, the development and perspective of landscape heterogeneity and biodiversity were summarized. The further studies should focus on relationships between agro-landscape context and biodiversity and its mechanisms based on spato-temporal heterogeneity of landscape.
2016, 24(4): 451-459.
Abstract:
Recent increases in agricultural productivity have largely been attributed to the availability of high-yielding varieties, farm irrigation and agrochemical inputs. However, many of the inputs and practices of intensive agriculture have remained detrimental to human health, environmental quality and biodiversity conservation. The shortage of intensive modern agriculture requires “agriculture rethinking” and learning back from traditional agricultural systems. Conservation of existing biodiversity in traditional agricultural systems and the adoption of biodiversity-based practices have been proposed as a way of improving the sustainability of agricultural production. In 2002, the Food and Agriculture Organization of the United Nations (FAO) started an initiative of Globally Important Agricultural Heritage Systems (GIAHS) that emphasized dynamic conservation ideas. FAO defined GHAHS as “remarkable land use systems and landscapes rich in globally significant biological diversity evolving from the co-adaptation of a community with its environment and its needs and aspirations for sustainable development”. The GIAHS initiative aimed to establish the basis for international recognition, dynamic conservation and sustainable development management of such systems as agricultural biodiversity and the associated biodiversity, knowledge systems, food and livelihood security, landscapes and cultures. Since then, an increasing number of countries and international organizations have accepted the concept of GIAHS with the related dynamic conservation ideology, as especially supported by Global Environment Facility (GEF). Over five years of implementation of GEF project in pilot countries have shown that not only agrobiodiversity and cultural diversity been effectively protected, but also sustainable socio-economic development has been well promoted. Based on 11 GIAHS sites in China, this paper analyzed the agrobiodiversity features from the view of genetic diversity, species diversity, ecosystem diversity, landscape diversity and cultural diversity. It then illustrated the ecological thoughts and principles, and some suggestions were put forward for conservation and utilization of agrobiodiversity. The approaches included the establishment of monitoring and evaluation systems, intensification of agrobiodiversity conservation and sustainable management research, formulation of incentive mechanisms for agrobiodiversity, and setting up of self-supporting and sustainable development mechanisms.
Recent increases in agricultural productivity have largely been attributed to the availability of high-yielding varieties, farm irrigation and agrochemical inputs. However, many of the inputs and practices of intensive agriculture have remained detrimental to human health, environmental quality and biodiversity conservation. The shortage of intensive modern agriculture requires “agriculture rethinking” and learning back from traditional agricultural systems. Conservation of existing biodiversity in traditional agricultural systems and the adoption of biodiversity-based practices have been proposed as a way of improving the sustainability of agricultural production. In 2002, the Food and Agriculture Organization of the United Nations (FAO) started an initiative of Globally Important Agricultural Heritage Systems (GIAHS) that emphasized dynamic conservation ideas. FAO defined GHAHS as “remarkable land use systems and landscapes rich in globally significant biological diversity evolving from the co-adaptation of a community with its environment and its needs and aspirations for sustainable development”. The GIAHS initiative aimed to establish the basis for international recognition, dynamic conservation and sustainable development management of such systems as agricultural biodiversity and the associated biodiversity, knowledge systems, food and livelihood security, landscapes and cultures. Since then, an increasing number of countries and international organizations have accepted the concept of GIAHS with the related dynamic conservation ideology, as especially supported by Global Environment Facility (GEF). Over five years of implementation of GEF project in pilot countries have shown that not only agrobiodiversity and cultural diversity been effectively protected, but also sustainable socio-economic development has been well promoted. Based on 11 GIAHS sites in China, this paper analyzed the agrobiodiversity features from the view of genetic diversity, species diversity, ecosystem diversity, landscape diversity and cultural diversity. It then illustrated the ecological thoughts and principles, and some suggestions were put forward for conservation and utilization of agrobiodiversity. The approaches included the establishment of monitoring and evaluation systems, intensification of agrobiodiversity conservation and sustainable management research, formulation of incentive mechanisms for agrobiodiversity, and setting up of self-supporting and sustainable development mechanisms.
2016, 24(4): 460-469.
Abstract:
Terraces are old agricultural field systems created by the ancestors according to the local terrain and which still perform their production function today. These land use systems clearly show the wisdom and abilities of human to adapting and to takinge advantages of the natural environment. Nowadays, the tillage and management experiences and traditional agricultural knowledge on terrace systems can offer important insights and reference pointss for the sustainable development of modern agriculture. With industrialization and urbanization, however, the limitations of terrace agriculture in production efficiency are more and more obvious, which has led to a series of natural and man-made environmental and societal problems due to the terrain limits for using farm machines and overwhelming development of tourism. These negative effects have led to the near collapse of terrace agriculture. Thus, a series of research projects on the protection of terrace agriculture have been conducted. This paper reviewsed most available works on the protection of rice terraces in three aspects, which includeing protected objects, existing problems and causes, and protective measures. In tThe protected objects were, mainly the landscapes, ecosystem services and social cultures in rice terrace areas are in three main parts. The protected landscape elements included terrace structures, water conservation forests, farm irrigation systems and villages. The key protected objects in the ecosystems covered traditional crop varieties, biodiversity, environmental quality of terraces and the comprehensive agricultural patterns. The protected social culture mainly consisteds of material cultures (e.g., traditional costumes and old buildings), spiritual cultures (e.g., ethnic songs and dances and traditional festivals), and system cultures (e.g., management of water resources and forests). The challenges facing rice terrace systems contained landscape destruction, environmental pollution, loss of biodiversity and disappearance of traditional cultures. These challenges weare primarily caused by the impacts of modern science and technology, market demands, low comparative advantages of traditional agriculture and unscientific industrial development. As to these challenges, many protective measures need to be implemented. They wereare grouped into three types: reasonable industrial development, building institutions and protective management mechanisms, and developing scientific research, based on searchable and referable protection of rice terraces. In the future, studies on rice terrace conservation should focus on mechanisms of key terrace issues, case studies, comprehensive subject researches, long-term observation studies and industrial development researches.
Terraces are old agricultural field systems created by the ancestors according to the local terrain and which still perform their production function today. These land use systems clearly show the wisdom and abilities of human to adapting and to takinge advantages of the natural environment. Nowadays, the tillage and management experiences and traditional agricultural knowledge on terrace systems can offer important insights and reference pointss for the sustainable development of modern agriculture. With industrialization and urbanization, however, the limitations of terrace agriculture in production efficiency are more and more obvious, which has led to a series of natural and man-made environmental and societal problems due to the terrain limits for using farm machines and overwhelming development of tourism. These negative effects have led to the near collapse of terrace agriculture. Thus, a series of research projects on the protection of terrace agriculture have been conducted. This paper reviewsed most available works on the protection of rice terraces in three aspects, which includeing protected objects, existing problems and causes, and protective measures. In tThe protected objects were, mainly the landscapes, ecosystem services and social cultures in rice terrace areas are in three main parts. The protected landscape elements included terrace structures, water conservation forests, farm irrigation systems and villages. The key protected objects in the ecosystems covered traditional crop varieties, biodiversity, environmental quality of terraces and the comprehensive agricultural patterns. The protected social culture mainly consisteds of material cultures (e.g., traditional costumes and old buildings), spiritual cultures (e.g., ethnic songs and dances and traditional festivals), and system cultures (e.g., management of water resources and forests). The challenges facing rice terrace systems contained landscape destruction, environmental pollution, loss of biodiversity and disappearance of traditional cultures. These challenges weare primarily caused by the impacts of modern science and technology, market demands, low comparative advantages of traditional agriculture and unscientific industrial development. As to these challenges, many protective measures need to be implemented. They wereare grouped into three types: reasonable industrial development, building institutions and protective management mechanisms, and developing scientific research, based on searchable and referable protection of rice terraces. In the future, studies on rice terrace conservation should focus on mechanisms of key terrace issues, case studies, comprehensive subject researches, long-term observation studies and industrial development researches.
2016, 24(4): 470-477.
Abstract:
Analysis of phospholipid fatty acids (PLFA) is an effective non-culture-based technique for information on living soil microbial community. PLFA is an important component of microbial cell membranes. Microbes can synthesize this special PLFA through various biochemical pathways hence some PLFA can be used as biomarker for a microbial community. When coupled with stable isotope 13C-labeled (13C-PLFA) technique, PLFA can be used to identify in situ structures of soil microbial communities. This can also be used to explore soil microbial functional communities responsible for metabolic processes of soil carbon sources in soil ecosystem, thus providing abundant information about microbial interactions in complex communities. This technique has the potential for wide future applications. The principle of 13C-PLFA technique is as follows: 1) adding 13C-rich substrates to the soils assimilated by some members of the soil microbial community; 2) extracting and purifying PLFA from soil substrate mixtures; 3) determining 13C value of PLFA using gas chromatography combustion isotope ratio mass spectrometry (GC-C-IRMS); and 4) deriving required information by comparative analysis. This study introduced the principle of 13C-PLFA technique and reviewed the applications of 13C-PLFA in the fields of photosynthetic carbon utilization by rhizosphere microorganisms, priming effects of soil organic matter decomposition and mineralization, microbial oxidation of methane, degradation of organic pollutants and microbial utilization of exogenous simple and complicated carbon sources. The limitations and application potentials of this technique were also discussed. It was concluded that 13C-PLFA method was an excellent way of providing insight into the relations between microbial community composition and soil biogeochemical cycle.
Analysis of phospholipid fatty acids (PLFA) is an effective non-culture-based technique for information on living soil microbial community. PLFA is an important component of microbial cell membranes. Microbes can synthesize this special PLFA through various biochemical pathways hence some PLFA can be used as biomarker for a microbial community. When coupled with stable isotope 13C-labeled (13C-PLFA) technique, PLFA can be used to identify in situ structures of soil microbial communities. This can also be used to explore soil microbial functional communities responsible for metabolic processes of soil carbon sources in soil ecosystem, thus providing abundant information about microbial interactions in complex communities. This technique has the potential for wide future applications. The principle of 13C-PLFA technique is as follows: 1) adding 13C-rich substrates to the soils assimilated by some members of the soil microbial community; 2) extracting and purifying PLFA from soil substrate mixtures; 3) determining 13C value of PLFA using gas chromatography combustion isotope ratio mass spectrometry (GC-C-IRMS); and 4) deriving required information by comparative analysis. This study introduced the principle of 13C-PLFA technique and reviewed the applications of 13C-PLFA in the fields of photosynthetic carbon utilization by rhizosphere microorganisms, priming effects of soil organic matter decomposition and mineralization, microbial oxidation of methane, degradation of organic pollutants and microbial utilization of exogenous simple and complicated carbon sources. The limitations and application potentials of this technique were also discussed. It was concluded that 13C-PLFA method was an excellent way of providing insight into the relations between microbial community composition and soil biogeochemical cycle.
2016, 24(4): 478-488.
Abstract:
Intercropping has an outstandingly long history in China. Studies have reported several advantages of cereal- legume intercropping systems, including increased yields, land use efficiency, natural resources utilization, and pest and disease control. This has a huge potential to significantly contribute to the sustainability of modern agriculture. As cereal crop, sugarcane is a major economic crop used in the production of sugar in China. Its wide-row planting space and slow growth rate during initial growth stage provide the required niche of space and resources for intercropping. However, long-term mono-cropping of sugarcane along with the overuse of nitrogen fertilizer has induced severe nitrous pollution in the environment and high cost of agricultural production in South China. Sugarcane-soybean intercropping can reduce nitrogen application while maintaining high crop yield, in turn reducing the overall cost of farming, enriching soil fertility and enhancing soil carbon sequestration in the field. However, few studies have investigated carbon balance under sugarcane intercropping and carbon sequestration in sugarcane intercropping fields. The objective of this study was to determine the effects of sugarcane and soybean intercropping under reduced nitrogen fertilizer on soil carbon balance. This study will further strengthen the scientific basis for the uptake and utilization of soil nutrient and the relationships among nutrition utilization and environmental factors under intercropping systems. To that end, a field experiment was conducted in 2012–2013 in South China Agriculture University. The study analyzed carbon balance and sequestration in farmlands in sugarcane-soybean intercropping systems with crop line ratio of 1︰1, sugarcane-soybean intercropping systems with crop line ratio of 1︰2, monocropped sugarcane (MS) under two nitrogen levels (N1, 300 kg·hm-2 and N2, 525 kg·hm-2) and monocropped soybean under zero nitrogen supply during crop growth season. Carbon balance and sequestration in farmland soils were investigated in this study using Input-Output Analysis, where carbon input and output were quantified for crop growth period in order to determine the intensity of carbon sink. The results showed that carbon input under sugarcane-soybean (1︰2) intercropping system was significantly higher than that under monoculture sugarcane and sugarcane-soybean (1︰1) intercropping under two nitrogen application levels. Compared with sugarcane-soybean (1︰1) intercropping and monoculture sugarcane, carbon output under sugarcane-soybean (1︰2) intercropping was significantly decreased with reducing nitrogen application in 2012, although there was no significant difference in 2013. After harvesting sugarcane, soil carbon storage under sugarcane-soybean intercropping systems with reduced nitrogen application was significantly higher than that under monoculture sugarcane. Carbon budget analysis for sugarcane-soybean intercropping systems showed that sugarcane-soybean (1︰2) intercropping was a good net carbon sink with high carbon fixation of 2 956.35 kg·hm-2 in 2012, and 872.59 kg·hm-2 in 2013 under reduced nitrogen application conditions. It was noted that sugarcane-soybean (1︰2) intercropping with reduced nitrogen application had better carbon storage potential. In addition, the value of land equivalent ratio (LER) of sugarcane-soybean intercropping systems exceeded 1.0 in 2012 and 2013. Also LER of sugarcane-soybean (1︰2) intercropping system with reduced nitrogen application was higher than 1.0. In conclusion, sugarcane-soybean intercropping system (1︰2) with reduced nitrogen application was a feasible production mode for the sustainability of modern agriculture.
Intercropping has an outstandingly long history in China. Studies have reported several advantages of cereal- legume intercropping systems, including increased yields, land use efficiency, natural resources utilization, and pest and disease control. This has a huge potential to significantly contribute to the sustainability of modern agriculture. As cereal crop, sugarcane is a major economic crop used in the production of sugar in China. Its wide-row planting space and slow growth rate during initial growth stage provide the required niche of space and resources for intercropping. However, long-term mono-cropping of sugarcane along with the overuse of nitrogen fertilizer has induced severe nitrous pollution in the environment and high cost of agricultural production in South China. Sugarcane-soybean intercropping can reduce nitrogen application while maintaining high crop yield, in turn reducing the overall cost of farming, enriching soil fertility and enhancing soil carbon sequestration in the field. However, few studies have investigated carbon balance under sugarcane intercropping and carbon sequestration in sugarcane intercropping fields. The objective of this study was to determine the effects of sugarcane and soybean intercropping under reduced nitrogen fertilizer on soil carbon balance. This study will further strengthen the scientific basis for the uptake and utilization of soil nutrient and the relationships among nutrition utilization and environmental factors under intercropping systems. To that end, a field experiment was conducted in 2012–2013 in South China Agriculture University. The study analyzed carbon balance and sequestration in farmlands in sugarcane-soybean intercropping systems with crop line ratio of 1︰1, sugarcane-soybean intercropping systems with crop line ratio of 1︰2, monocropped sugarcane (MS) under two nitrogen levels (N1, 300 kg·hm-2 and N2, 525 kg·hm-2) and monocropped soybean under zero nitrogen supply during crop growth season. Carbon balance and sequestration in farmland soils were investigated in this study using Input-Output Analysis, where carbon input and output were quantified for crop growth period in order to determine the intensity of carbon sink. The results showed that carbon input under sugarcane-soybean (1︰2) intercropping system was significantly higher than that under monoculture sugarcane and sugarcane-soybean (1︰1) intercropping under two nitrogen application levels. Compared with sugarcane-soybean (1︰1) intercropping and monoculture sugarcane, carbon output under sugarcane-soybean (1︰2) intercropping was significantly decreased with reducing nitrogen application in 2012, although there was no significant difference in 2013. After harvesting sugarcane, soil carbon storage under sugarcane-soybean intercropping systems with reduced nitrogen application was significantly higher than that under monoculture sugarcane. Carbon budget analysis for sugarcane-soybean intercropping systems showed that sugarcane-soybean (1︰2) intercropping was a good net carbon sink with high carbon fixation of 2 956.35 kg·hm-2 in 2012, and 872.59 kg·hm-2 in 2013 under reduced nitrogen application conditions. It was noted that sugarcane-soybean (1︰2) intercropping with reduced nitrogen application had better carbon storage potential. In addition, the value of land equivalent ratio (LER) of sugarcane-soybean intercropping systems exceeded 1.0 in 2012 and 2013. Also LER of sugarcane-soybean (1︰2) intercropping system with reduced nitrogen application was higher than 1.0. In conclusion, sugarcane-soybean intercropping system (1︰2) with reduced nitrogen application was a feasible production mode for the sustainability of modern agriculture.
2016, 24(4): 489-498.
Abstract:
Straw incorporation to soil is an effective way to utilize plant straw resource. It improves soil fertility and regulates soil microbial community structure and diversity. Despite this, there are few reports on the effect of different straw incorporation modes on soil fertility and microbial diversity in sandy soils in Xinjiang. Field trials were conducted with direct straw incorporation (NPKS), abdomen-digested straw incorporation (sheep manure application, NPKM, 15.0 thm2) and carbonized straw incorporation (biochar application, NPKB1, 2.5 thm2 and NPKB2, 15.0 thm2) to the field to evaluate the effects of different straw incorporation modes on soil nutrient, microbial quantity, enzyme activity and microbial carbon utilization in sandy soils in southern Xinjiang during the period of 2010–2012. The results showed that: 1) Compare with the control (chemical fertilization, NPK) treatment, different straw incorporation modes significantly improved soil nutrient of sandy soils. NPKM treatment was the best, followed by NPKB2 treatment, NPKS treatment and then NPKB1 treatment. 2) Different straw incorporation modes had considerable effect on soil microbial population. The treatments increased the populations of soil bacteria and actinomycete and the number of physiological groups of bacterial. Compared with NPK treatment, the population of bacteria was highest under NPKB2 treatment while the population of actinomycete was highest under NPKM treatment; increasing significantly by 413.16% and 574.19%, respectively. The number of physiological groups of bacterial under NPKB1 and NPKB2 treatments was higher than that under NPKS treatment. Soil enzymes activities of different straw incorporation modes were generally higher than that under NPK treatment, and NPKM treatment had the best effect on soil enzymes activities. 3) Biolog carbon resources utilization analysis showed that different straw incorporation modes improved soil microbial activity and richness index. Principal component analysis showed that obvious differences in soil microbial community among different straw incorporation modes. The differences in carbon resources utilization were mostly caused by carboxylic acids and carbohydrates. Cluster analysis showed that between NPKB2 and NPKM, and between NPKB1 and NPKS had similar microbial functions. The results indicated that different straw incorporation modes significantly improved soil microbial activity and functional diversity in sandy soils. However, the effect of soil improvement was different for different modes. The 3-years (2010–2012) experimental results suggested that abdomen-digested straw incorporation and carbonized straw incorporation to the field had better effects, while direct straw incorporation to the field increased the risk of soil borne diseases. The results added to the existing theoretical guidance on establishing modern eco-efficient fertilization modes in sandy soils in southern Xinjiang.
Straw incorporation to soil is an effective way to utilize plant straw resource. It improves soil fertility and regulates soil microbial community structure and diversity. Despite this, there are few reports on the effect of different straw incorporation modes on soil fertility and microbial diversity in sandy soils in Xinjiang. Field trials were conducted with direct straw incorporation (NPKS), abdomen-digested straw incorporation (sheep manure application, NPKM, 15.0 thm2) and carbonized straw incorporation (biochar application, NPKB1, 2.5 thm2 and NPKB2, 15.0 thm2) to the field to evaluate the effects of different straw incorporation modes on soil nutrient, microbial quantity, enzyme activity and microbial carbon utilization in sandy soils in southern Xinjiang during the period of 2010–2012. The results showed that: 1) Compare with the control (chemical fertilization, NPK) treatment, different straw incorporation modes significantly improved soil nutrient of sandy soils. NPKM treatment was the best, followed by NPKB2 treatment, NPKS treatment and then NPKB1 treatment. 2) Different straw incorporation modes had considerable effect on soil microbial population. The treatments increased the populations of soil bacteria and actinomycete and the number of physiological groups of bacterial. Compared with NPK treatment, the population of bacteria was highest under NPKB2 treatment while the population of actinomycete was highest under NPKM treatment; increasing significantly by 413.16% and 574.19%, respectively. The number of physiological groups of bacterial under NPKB1 and NPKB2 treatments was higher than that under NPKS treatment. Soil enzymes activities of different straw incorporation modes were generally higher than that under NPK treatment, and NPKM treatment had the best effect on soil enzymes activities. 3) Biolog carbon resources utilization analysis showed that different straw incorporation modes improved soil microbial activity and richness index. Principal component analysis showed that obvious differences in soil microbial community among different straw incorporation modes. The differences in carbon resources utilization were mostly caused by carboxylic acids and carbohydrates. Cluster analysis showed that between NPKB2 and NPKM, and between NPKB1 and NPKS had similar microbial functions. The results indicated that different straw incorporation modes significantly improved soil microbial activity and functional diversity in sandy soils. However, the effect of soil improvement was different for different modes. The 3-years (2010–2012) experimental results suggested that abdomen-digested straw incorporation and carbonized straw incorporation to the field had better effects, while direct straw incorporation to the field increased the risk of soil borne diseases. The results added to the existing theoretical guidance on establishing modern eco-efficient fertilization modes in sandy soils in southern Xinjiang.
2016, 24(4): 499-505.
Abstract:
The reduction in the ratio of red light (R) to far-red light (FR) is an important signal of shade stress in nature. The objective of this study was to investigate the response mechanism of soybean seedlings to low R/FR signals. To this end, a pot culture experiment was conducted to study the effect of normal and low R/FR light irradiation on the morphology, photosynthetic characteristics and chlorophyll fluorescence of two soybean varieties (Glycine max L.) seedlings — ‘Nandou12 ‘and ‘Nan032-4’. The results indicated that compared with seedlings under normal light, low-R/FR light increased soybean plant height, leaf area, petiole length and internode length, but reduced stem diameter. Plant height, petiole length and internode length of ‘Nandou12’ increased by 7.86%, 81.48% and 26.55%, and that of ‘Nan032-4’ increased by 3.95%, 76.67% and 20.00%, respectively, compared with the corresponding normal light treatment. Also compared with seedlings under normal light, leaf photosynthetic rate (Pn), transpiration rate (Tr), stomatal conductance (Gs) and photochemical quenching coefficient (qN) of seedlings under low R/FR treatment increased. However, intercellular CO2 concentration (Ci), initial fluorescence intensity (Fo), maximum fluorescence (Fm), maximum photochemical efficiency (Fv/Fm), actual PSⅡ photochemical efficiency (ΦPSⅡ) and light chemical quenching coefficient (qP) decreased under low R/FR treatment. Meanwhile, low-R/FR increased dry matter accumulation. Under low R/FR treatment, Pn and dry matter accumulation of ‘Nandou12’ increased by 37.21% and 12.35% and those of ‘Nan032-4’ increased by 39.04% and 17.36%, respectively. Compared with seedlings under normal light treatment, Ci of ‘Nandou12’ and ‘Nan032-4’ decreased by 9.29% and 11.72%, respectively. However, different soybean varieties had different degrees of response to low-R/FR. Under low-R/FR light condition, the plant height, internode length and petiole length of ‘Nandou12’ were lower than those of ‘Nan032-4’, however, the leaf area, stem diameter, light energy conversion efficiency, photosynthetic rate (Pn), stomatal conductance (Gs) and dry matter accumulation of ‘Nandou12’ seedlings were higher than those of ‘Nan032-4’. This indicated that ‘Nandou12’ variety had stronger shade tolerance than ‘Nan032-4’ variety. Furthermore, this study confirmed that soybean was sufficiently sensitive to low-R/FR shading signal, but different varieties had different sensitivities. Therefore, in intercropping systems, it was recommended to use shade-tolerant soybean varieties to reduce lodging and increase soybean yield.
The reduction in the ratio of red light (R) to far-red light (FR) is an important signal of shade stress in nature. The objective of this study was to investigate the response mechanism of soybean seedlings to low R/FR signals. To this end, a pot culture experiment was conducted to study the effect of normal and low R/FR light irradiation on the morphology, photosynthetic characteristics and chlorophyll fluorescence of two soybean varieties (Glycine max L.) seedlings — ‘Nandou12 ‘and ‘Nan032-4’. The results indicated that compared with seedlings under normal light, low-R/FR light increased soybean plant height, leaf area, petiole length and internode length, but reduced stem diameter. Plant height, petiole length and internode length of ‘Nandou12’ increased by 7.86%, 81.48% and 26.55%, and that of ‘Nan032-4’ increased by 3.95%, 76.67% and 20.00%, respectively, compared with the corresponding normal light treatment. Also compared with seedlings under normal light, leaf photosynthetic rate (Pn), transpiration rate (Tr), stomatal conductance (Gs) and photochemical quenching coefficient (qN) of seedlings under low R/FR treatment increased. However, intercellular CO2 concentration (Ci), initial fluorescence intensity (Fo), maximum fluorescence (Fm), maximum photochemical efficiency (Fv/Fm), actual PSⅡ photochemical efficiency (ΦPSⅡ) and light chemical quenching coefficient (qP) decreased under low R/FR treatment. Meanwhile, low-R/FR increased dry matter accumulation. Under low R/FR treatment, Pn and dry matter accumulation of ‘Nandou12’ increased by 37.21% and 12.35% and those of ‘Nan032-4’ increased by 39.04% and 17.36%, respectively. Compared with seedlings under normal light treatment, Ci of ‘Nandou12’ and ‘Nan032-4’ decreased by 9.29% and 11.72%, respectively. However, different soybean varieties had different degrees of response to low-R/FR. Under low-R/FR light condition, the plant height, internode length and petiole length of ‘Nandou12’ were lower than those of ‘Nan032-4’, however, the leaf area, stem diameter, light energy conversion efficiency, photosynthetic rate (Pn), stomatal conductance (Gs) and dry matter accumulation of ‘Nandou12’ seedlings were higher than those of ‘Nan032-4’. This indicated that ‘Nandou12’ variety had stronger shade tolerance than ‘Nan032-4’ variety. Furthermore, this study confirmed that soybean was sufficiently sensitive to low-R/FR shading signal, but different varieties had different sensitivities. Therefore, in intercropping systems, it was recommended to use shade-tolerant soybean varieties to reduce lodging and increase soybean yield.
MAO Ruzhi,
ZHANG Guotao,
SHAO Jianhui,
DU Fei,
DENG Weiping,
ZHAO Xinjie,
ZHU Shusheng,
ZHU Youyong,
HE Xiahong
2016, 24(4): 506-516.
Abstract:
To illustrate the adaptability and quality characteristics of ‘Merlot’ grape berries in high altitude production areas, the metabolites contents and metabolomics of ‘Merlot’ grape berries were analyzed in relation to meteorological factors at low (41 m) and high (2 343 m) altitude wine-producing areas. In this investigation, meteorological factors at low/high-altitude of wine-producing areas were monitored by GPRS-based system. The pH and contents of soluble solids, total acid content, reducing sugars, anthocyanin, total phenol, tannin, flavonoid, flavone and proteins of ‘Merlot’ grape berries were determined. Furthermore, GC/TOF-MS technique was used to analyze the difference in metabolome of ‘Merlot’ grape berries between different altitudes. The results showed that average daily sunshine duration, total radiation during grapes growth period, average daily radiation, average daily temperature difference, average daily temperature and effective cumulative temperature during growth period were higher in high-altitude than those in low-altitude regions. The contents of soluble solid, tannin and reducing sugars of ‘Merlot’ grape berries increased, while the contents of total phenols and anthocyanin decreased in high-altitude wine-producing area, compared with those in low-altitude wine-producing area. Metabolic pathway analysis indicated that ‘Merlot’ grape berries in high-altitude wine-producing area accumulated more amino acids, organic acids, alcohols, polyphenols and sugars than those in low-altitude wine-producing area. Metabolic pathway enrichment analysis showed that 8 amino acid metabolome pathways, 4 carbohydrate metabolome pathways, 3 lipid metabolome pathways and 3 nitrogen metabolome pathways of ‘Merlot’ grape berries were regulated in high-altitude region. DCCA (Detrended Canonical Correspondence Analysis) indicated that average daily sunshine duration, total radiation, average daily radiation, average daily temperature difference, average daily temperature and effective cumulative temperature during growth period were the driving factors of ‘Merlot’ berries quality and metabolites. In conclusion, climatic factors were the main driving factors inducing metabolite differences between ‘Merlot’ grapes berries growing in low- and high-altitude regions. Thus, to adjust metabolites profiles and metabolic pathways was a kind of strategies of ‘Merlot’ grapes for adapting to high altitude ecological environments.
To illustrate the adaptability and quality characteristics of ‘Merlot’ grape berries in high altitude production areas, the metabolites contents and metabolomics of ‘Merlot’ grape berries were analyzed in relation to meteorological factors at low (41 m) and high (2 343 m) altitude wine-producing areas. In this investigation, meteorological factors at low/high-altitude of wine-producing areas were monitored by GPRS-based system. The pH and contents of soluble solids, total acid content, reducing sugars, anthocyanin, total phenol, tannin, flavonoid, flavone and proteins of ‘Merlot’ grape berries were determined. Furthermore, GC/TOF-MS technique was used to analyze the difference in metabolome of ‘Merlot’ grape berries between different altitudes. The results showed that average daily sunshine duration, total radiation during grapes growth period, average daily radiation, average daily temperature difference, average daily temperature and effective cumulative temperature during growth period were higher in high-altitude than those in low-altitude regions. The contents of soluble solid, tannin and reducing sugars of ‘Merlot’ grape berries increased, while the contents of total phenols and anthocyanin decreased in high-altitude wine-producing area, compared with those in low-altitude wine-producing area. Metabolic pathway analysis indicated that ‘Merlot’ grape berries in high-altitude wine-producing area accumulated more amino acids, organic acids, alcohols, polyphenols and sugars than those in low-altitude wine-producing area. Metabolic pathway enrichment analysis showed that 8 amino acid metabolome pathways, 4 carbohydrate metabolome pathways, 3 lipid metabolome pathways and 3 nitrogen metabolome pathways of ‘Merlot’ grape berries were regulated in high-altitude region. DCCA (Detrended Canonical Correspondence Analysis) indicated that average daily sunshine duration, total radiation, average daily radiation, average daily temperature difference, average daily temperature and effective cumulative temperature during growth period were the driving factors of ‘Merlot’ berries quality and metabolites. In conclusion, climatic factors were the main driving factors inducing metabolite differences between ‘Merlot’ grapes berries growing in low- and high-altitude regions. Thus, to adjust metabolites profiles and metabolic pathways was a kind of strategies of ‘Merlot’ grapes for adapting to high altitude ecological environments.
2016, 24(4): 517-523.
Abstract:
The interaction of zinc (Zn) and cadmium (Cd) in soil is critical for the uptake and transport of Cd in rice plants. However, the effect of Zn levels on the interactions of Zn and Cd or on the rate of transport of Cd in rice plants is still not entirely clear. In this study, rice plant biomass, and Cd transport and distribution in rice plant were investigated in hydroponic experiment of mild Cd pollution with exogenous Zn addition. In the experiment, Cd concentrations were 0.01 mg·L1 (low dose), 0.03 mg·L1 (medium dose), 0.09 mg·L1 (high dose), and 0 mg·L1 (control); and exogenous Zn were 0.025 mg·L1, 0.05 mg·L1, 0.1 mg·L1, 0.2 mg·L1. The aim of the study was to determine the mechanism of interactions between Zn and Cd and to identify the optimal Zn concentration that effectively reduced Cd pollution in rice. The results showed that biomasses of different parts of rice plant increased significantly with increasing concentration of Zn. The increase of biomass was highest in 0.05 mg·L1 exogenous Zn treatment. However, there was no significant increase when Zn concentration exceeded 0.05 mg·L1. Due to the low dose of Cd in the experiment, there was no significant variation in rice plant biomass with increasing Cd concentration without exogenous Zn. Under Zn-free condition, the ratio of cytoplasm Cd to cell-wall Cd in rice root reduced from 2.88 to 1.04 with increasing Cd concentration. With the applying of exogenous Zn, the ratio of cytoplasm Cd to cell-wall Cd showed increasing tendency, especially under 0.03 mg·L1 Cd. Under medium-to-low Cd dose (0.01–0.03 mg·L1), Zn significantly inhibited the uptake and transport of Cd in root, which significantly reduced Cd concentration in rice cytoplasm and cell wall. Compared with Zn-free treatment, 0.05 mg·L1 Zn significantly reduced Cd content in rice. The concentration of Cd in plant root, stem and leaf reduced by 38%, 71% and 65% under low-dose Cd and by 44%, 79% and 69% under medium- dose Cd, respectively. The rate of transport of Cd between roots and stems, and between roots and leaves decreased by 53% and 44% under low-dose Cd, and by 62% and 40% under medium-dose Cd, respectively. When Zn concentration exceeded 0.05 mg·L1, there was no obvious change in the concentration of Cd in roots, stems and leaves along with the rate of Cd transport in rice. Under high concentration of Cd (0.09 mg·L1), there was no obvious decline in Cd concentration in roots, stems and leaves due to addition of exogenous Zn. Addition of Zn promoted the absorption of Cd by rice stem and leaf. There was no obvious antagonism between Zn and Cd under high Cd concentration, although the synergies were obvious. Thus under medium-to-low dose Cd conditions, Zn controlled the phyto-availability of Cd due to obvious antagonistic effects between Zn and Cd. Application of 0.05 mg·L1 Zn significantly reduced Cd phyto-availability and migration in rice and maximally increased plant biomass under low concentrations of Cd in hydroponic cultures.
The interaction of zinc (Zn) and cadmium (Cd) in soil is critical for the uptake and transport of Cd in rice plants. However, the effect of Zn levels on the interactions of Zn and Cd or on the rate of transport of Cd in rice plants is still not entirely clear. In this study, rice plant biomass, and Cd transport and distribution in rice plant were investigated in hydroponic experiment of mild Cd pollution with exogenous Zn addition. In the experiment, Cd concentrations were 0.01 mg·L1 (low dose), 0.03 mg·L1 (medium dose), 0.09 mg·L1 (high dose), and 0 mg·L1 (control); and exogenous Zn were 0.025 mg·L1, 0.05 mg·L1, 0.1 mg·L1, 0.2 mg·L1. The aim of the study was to determine the mechanism of interactions between Zn and Cd and to identify the optimal Zn concentration that effectively reduced Cd pollution in rice. The results showed that biomasses of different parts of rice plant increased significantly with increasing concentration of Zn. The increase of biomass was highest in 0.05 mg·L1 exogenous Zn treatment. However, there was no significant increase when Zn concentration exceeded 0.05 mg·L1. Due to the low dose of Cd in the experiment, there was no significant variation in rice plant biomass with increasing Cd concentration without exogenous Zn. Under Zn-free condition, the ratio of cytoplasm Cd to cell-wall Cd in rice root reduced from 2.88 to 1.04 with increasing Cd concentration. With the applying of exogenous Zn, the ratio of cytoplasm Cd to cell-wall Cd showed increasing tendency, especially under 0.03 mg·L1 Cd. Under medium-to-low Cd dose (0.01–0.03 mg·L1), Zn significantly inhibited the uptake and transport of Cd in root, which significantly reduced Cd concentration in rice cytoplasm and cell wall. Compared with Zn-free treatment, 0.05 mg·L1 Zn significantly reduced Cd content in rice. The concentration of Cd in plant root, stem and leaf reduced by 38%, 71% and 65% under low-dose Cd and by 44%, 79% and 69% under medium- dose Cd, respectively. The rate of transport of Cd between roots and stems, and between roots and leaves decreased by 53% and 44% under low-dose Cd, and by 62% and 40% under medium-dose Cd, respectively. When Zn concentration exceeded 0.05 mg·L1, there was no obvious change in the concentration of Cd in roots, stems and leaves along with the rate of Cd transport in rice. Under high concentration of Cd (0.09 mg·L1), there was no obvious decline in Cd concentration in roots, stems and leaves due to addition of exogenous Zn. Addition of Zn promoted the absorption of Cd by rice stem and leaf. There was no obvious antagonism between Zn and Cd under high Cd concentration, although the synergies were obvious. Thus under medium-to-low dose Cd conditions, Zn controlled the phyto-availability of Cd due to obvious antagonistic effects between Zn and Cd. Application of 0.05 mg·L1 Zn significantly reduced Cd phyto-availability and migration in rice and maximally increased plant biomass under low concentrations of Cd in hydroponic cultures.
2016, 24(4): 524-531.
Abstract:
Grassland grazing ecosystem is one of the most efficient consumption systems of the terrestrial ecosystem. There are few repeated studies on long-term effects of stocking rate on stability of grazing ecosystems. With Inner Mongolia Wulanchabu Stipa Breviflora desert steppe as a case study, nine years stationary experiment was conducted to study the effect of grazing on soil physical and chemical properties. The study tested the processes and mechanisms of soil degradation at different stocking rates with the aim of beneficial adoption of reasonable grazing management measures and promoting sustainable development of grassland animal husbandry. A randomized complete block design was set up with four stocking rate treatments and three replicates. The stocking rate treatments included the control [non-grazed enclosure (CK)], light stocking rate (LG), moderate stocking rate (MG) and heavy stocking rate (HG). Adult Mongolia sheep were used in continuous grazing system from June to November of each year in 2004–2012. The stocking rates were 0 sheeps·hm2 (CK), 0.91 sheeps·hm2 (LG), 1.82 sheeps·hm2 (MG) and 2.71 sheeps·hm2 (HG). Soil physical and chemical properties were measured in 2004–2012. The results showed that soil water content in the topsoil decreased significantly with increasing stocking rate after 9 years of continuous grazing. Soil bulk density decreased by 17.25% with extended grazing time (P < 0.05), but not significantly changed with stocking rate. The stocking rate had no significant influence on soil mechanical composition, pH, and contents of available phosphorus and potassium. However, soil organic matter significantly decreased (P < 0.05) in the 010 cm soil depth under HG treatment compared with other treatments. With increasing stoking rate, the content of sand in the soil increased and that of clay decreased. Also HG treatment significantly decreased soil respiration rate in 2012. Based on statistical results of stocking rate, stocking year and their interactions, soil physical and chemical conditions of S. breviflora desert steppe did not significantly change over the nine years of grazing. However, organic matter apparently showed a certain degree of degradation. Because of resilience, hysteresis and complexity of natural soil systems, it was recommended that studies on the effects of stocking rates on soil bulk density should be done for longer time periods.
Grassland grazing ecosystem is one of the most efficient consumption systems of the terrestrial ecosystem. There are few repeated studies on long-term effects of stocking rate on stability of grazing ecosystems. With Inner Mongolia Wulanchabu Stipa Breviflora desert steppe as a case study, nine years stationary experiment was conducted to study the effect of grazing on soil physical and chemical properties. The study tested the processes and mechanisms of soil degradation at different stocking rates with the aim of beneficial adoption of reasonable grazing management measures and promoting sustainable development of grassland animal husbandry. A randomized complete block design was set up with four stocking rate treatments and three replicates. The stocking rate treatments included the control [non-grazed enclosure (CK)], light stocking rate (LG), moderate stocking rate (MG) and heavy stocking rate (HG). Adult Mongolia sheep were used in continuous grazing system from June to November of each year in 2004–2012. The stocking rates were 0 sheeps·hm2 (CK), 0.91 sheeps·hm2 (LG), 1.82 sheeps·hm2 (MG) and 2.71 sheeps·hm2 (HG). Soil physical and chemical properties were measured in 2004–2012. The results showed that soil water content in the topsoil decreased significantly with increasing stocking rate after 9 years of continuous grazing. Soil bulk density decreased by 17.25% with extended grazing time (P < 0.05), but not significantly changed with stocking rate. The stocking rate had no significant influence on soil mechanical composition, pH, and contents of available phosphorus and potassium. However, soil organic matter significantly decreased (P < 0.05) in the 010 cm soil depth under HG treatment compared with other treatments. With increasing stoking rate, the content of sand in the soil increased and that of clay decreased. Also HG treatment significantly decreased soil respiration rate in 2012. Based on statistical results of stocking rate, stocking year and their interactions, soil physical and chemical conditions of S. breviflora desert steppe did not significantly change over the nine years of grazing. However, organic matter apparently showed a certain degree of degradation. Because of resilience, hysteresis and complexity of natural soil systems, it was recommended that studies on the effects of stocking rates on soil bulk density should be done for longer time periods.
2016, 24(4): 532-543.
Abstract:
The Qinghai-Tibet Plateau is considered to be ideal region for studying the response of natural ecosystems to climate change because its’ mountainous environments is one of the most fragile of the global ecosystems. The impacts of the changes in temperature and precipitation on the phenology varied among different grasslands. After experiencing a distinct warming in recent decades, some studies noted that remarkable variations in vegetation in the Qinghai-Tibet Plateau were potentially due to climate change. In order to determine the impacts of climate change on vegetation phenology and potential productivity, this paper used meteorological data during 1965–2013 in the Qinghai-Tibet Plateau (e.g., monthly temperature, precipitation and sunshine duration) of 107 meteorological stations, and extracted vegetation phenological indices using MODIS-derived normalized difference vegetation index data during 2000–2013, and used the Thornthwaite Memorial model and GIS techniques to analyze the spatial and temporal trends of potential climate-driven forage productivity in the Qinghai-Tibet Plateau. Then by analyzing 22 years of continuous observation data of growth stages of forage in the Qinghai-Tibet Plateau, the relationship between meteorological factors and major growth stages of forage was determined. Also the driving factors of the dynamics of potential climate productivity in the Qinghai-Tibet Plateau were determined. Furthermore, the relationship between temperature or precipitation and sunshine duration during forage growth period was determined based on regression analysis. The results showed that the potential climate productivity of forage in the Qinghai-Tibet Plateau was consistently varied with geographical region and spatial temperature distribution. Average temperature in the Qinghai-Tibet Plateau rose during the nearly 50-year period, increasing by 0.53 ℃(10a)1. Precipitation generally increased at the rate of 7.81 mm(10a)1, while sunshine duration decreased by 16.94 h(10a)1. Potential climate productivity of forage in the Qinghai-Tibet Plateau presented an increasing trend from 1965 to 2013, and spatial changes of the productivity, in turn, increased from northwest to southeast. Then potential climate productivity of forage in the north and south in the plateau significantly increased and there was less variation in the east of the plateau. Furthermore, the regreening, heading and blossoming of forages advanced, while yellowing and withering delayed year after year, which extended the forages phenological phases. Regreening stage of forage delayed from southeast to northwest, although withering stage showed no obvious change. Under drier and warmer conditions, phenological periods of grassland vegetation in the region became closely related to climate change. Then precipitation and sunshine duration were negatively correlated with phenological period of the grassland vegetation. Temperature was the dominant constraint on phenological phases of grassland vegetation in the study area. The study formed a relevant reference and basis for the protection of grassland ecosystems and enhancing potential climate productivity in Qinghai-Tibet Plateau.
The Qinghai-Tibet Plateau is considered to be ideal region for studying the response of natural ecosystems to climate change because its’ mountainous environments is one of the most fragile of the global ecosystems. The impacts of the changes in temperature and precipitation on the phenology varied among different grasslands. After experiencing a distinct warming in recent decades, some studies noted that remarkable variations in vegetation in the Qinghai-Tibet Plateau were potentially due to climate change. In order to determine the impacts of climate change on vegetation phenology and potential productivity, this paper used meteorological data during 1965–2013 in the Qinghai-Tibet Plateau (e.g., monthly temperature, precipitation and sunshine duration) of 107 meteorological stations, and extracted vegetation phenological indices using MODIS-derived normalized difference vegetation index data during 2000–2013, and used the Thornthwaite Memorial model and GIS techniques to analyze the spatial and temporal trends of potential climate-driven forage productivity in the Qinghai-Tibet Plateau. Then by analyzing 22 years of continuous observation data of growth stages of forage in the Qinghai-Tibet Plateau, the relationship between meteorological factors and major growth stages of forage was determined. Also the driving factors of the dynamics of potential climate productivity in the Qinghai-Tibet Plateau were determined. Furthermore, the relationship between temperature or precipitation and sunshine duration during forage growth period was determined based on regression analysis. The results showed that the potential climate productivity of forage in the Qinghai-Tibet Plateau was consistently varied with geographical region and spatial temperature distribution. Average temperature in the Qinghai-Tibet Plateau rose during the nearly 50-year period, increasing by 0.53 ℃(10a)1. Precipitation generally increased at the rate of 7.81 mm(10a)1, while sunshine duration decreased by 16.94 h(10a)1. Potential climate productivity of forage in the Qinghai-Tibet Plateau presented an increasing trend from 1965 to 2013, and spatial changes of the productivity, in turn, increased from northwest to southeast. Then potential climate productivity of forage in the north and south in the plateau significantly increased and there was less variation in the east of the plateau. Furthermore, the regreening, heading and blossoming of forages advanced, while yellowing and withering delayed year after year, which extended the forages phenological phases. Regreening stage of forage delayed from southeast to northwest, although withering stage showed no obvious change. Under drier and warmer conditions, phenological periods of grassland vegetation in the region became closely related to climate change. Then precipitation and sunshine duration were negatively correlated with phenological period of the grassland vegetation. Temperature was the dominant constraint on phenological phases of grassland vegetation in the study area. The study formed a relevant reference and basis for the protection of grassland ecosystems and enhancing potential climate productivity in Qinghai-Tibet Plateau.
2016, 24(4): 544-552.
Abstract:
In order to avoid the negative effects (e.g., rural culture disappearance) and aggravation of ecological risks of rural tourism development, landscape security pattern (LSP) was built (with consideration of rural nature and cultural landscape protection) using the minimum cumulative resistance model. Zixing Village in Jinjiang City, Fujian Province was used as a case study to explore land classification and spatial layout of rural tourism lands with LSP as constraint condition. The results showed that LSP in the study area included four ecological function zones, core protection zone, ecological buffer zone, ecological transition zone and human activity zone, with two kinds of source areas of forest and water. Land use characteristics of four zones were different and decided based on distribution of landscape and the state of land use. Tourism land use in the study area was classified into four types, including natural tourism land, cultural tourism land, facilities land and other tourism lands. The rules of land use for every type of tourism land were differed on the basis of LSP. Natural tourism land, composed of agricultural sightseeing zone and water tourist zone, was distributed in ecological buffer zones, ecological transition zones and human activity zones. This kind land use was based on the order of priority of original landscapes maintaining and landscapes repairing. Namely, for the natural tourism land, the land use was based on the current state of land use, and meantime, increased functions of tourism. This study classified the north of Jinxi District as agricultural experience zone, agricultural research institutes as agro-ecological sightseeing zone, and Zixi Reservoir and Jinxi as hydrological sightseeing zone. These zones as well as existing ruins and ancient buildings were the main cultural tourism lands. The cultural tourism lands were mainly distributed in core protection zones and ecological buffer zones. The use principle of the cultural tourism lands was maintenance and repairmen of original landscapes, such as forbidding any human activities but sightseeing tour. Facilities lands were mainly located in the zones of ecological transition and human activity. The lands were not only remolded by existing buildings, but also by increased quantity. Northwest of Dingxiyuan Village was planned as tourist center and Jinxing Village as family hostel and restaurant concentration area. Other tourism lands were mainly distributed in human activity zones, driven by maintenance of original landscapes. Other tourism lands were distributed mainly in Zixing industrial park. It was suggested that the spatial layout of rural tourism lands based on LSP were useful in coordinating the relationship between human and nature. It was meaningful for planning of rural tourism lands at theoretical and practical scales.
In order to avoid the negative effects (e.g., rural culture disappearance) and aggravation of ecological risks of rural tourism development, landscape security pattern (LSP) was built (with consideration of rural nature and cultural landscape protection) using the minimum cumulative resistance model. Zixing Village in Jinjiang City, Fujian Province was used as a case study to explore land classification and spatial layout of rural tourism lands with LSP as constraint condition. The results showed that LSP in the study area included four ecological function zones, core protection zone, ecological buffer zone, ecological transition zone and human activity zone, with two kinds of source areas of forest and water. Land use characteristics of four zones were different and decided based on distribution of landscape and the state of land use. Tourism land use in the study area was classified into four types, including natural tourism land, cultural tourism land, facilities land and other tourism lands. The rules of land use for every type of tourism land were differed on the basis of LSP. Natural tourism land, composed of agricultural sightseeing zone and water tourist zone, was distributed in ecological buffer zones, ecological transition zones and human activity zones. This kind land use was based on the order of priority of original landscapes maintaining and landscapes repairing. Namely, for the natural tourism land, the land use was based on the current state of land use, and meantime, increased functions of tourism. This study classified the north of Jinxi District as agricultural experience zone, agricultural research institutes as agro-ecological sightseeing zone, and Zixi Reservoir and Jinxi as hydrological sightseeing zone. These zones as well as existing ruins and ancient buildings were the main cultural tourism lands. The cultural tourism lands were mainly distributed in core protection zones and ecological buffer zones. The use principle of the cultural tourism lands was maintenance and repairmen of original landscapes, such as forbidding any human activities but sightseeing tour. Facilities lands were mainly located in the zones of ecological transition and human activity. The lands were not only remolded by existing buildings, but also by increased quantity. Northwest of Dingxiyuan Village was planned as tourist center and Jinxing Village as family hostel and restaurant concentration area. Other tourism lands were mainly distributed in human activity zones, driven by maintenance of original landscapes. Other tourism lands were distributed mainly in Zixing industrial park. It was suggested that the spatial layout of rural tourism lands based on LSP were useful in coordinating the relationship between human and nature. It was meaningful for planning of rural tourism lands at theoretical and practical scales.
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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