[Objective] To analyze the efficiency of Hunan agro-ecosystem in 1980- 2010. [Method] This paper adopts the emergy methods to evaluate the emergy input and output. [Result] The growth of total emergy input was mainly ...[Objective] To analyze the efficiency of Hunan agro-ecosystem in 1980- 2010. [Method] This paper adopts the emergy methods to evaluate the emergy input and output. [Result] The growth of total emergy input was mainly caused by the auxiliary factors in this phase. The proportion of the nonrenewable purchased emergy input to the total auxiliary emergy input increased from 21.80% in 1980 to 33.04% in 2010. In 1980-2010 the total emergy output of the system increased by 2.43 times, the proportions of the stock farming emergy output and fishery emergy output to the total emergy output increased sharply, while those of the planting emergy output and forestry emergy output showed a considerable decline. [Conclusion] The emergy yield ratio of this system was improved but its sustainability was worrying.展开更多
To accurately evaluate the carbon sequestration potential and better elucidate the relationship between the carbon cycle and regional climate change, using eddy covariance system, we conducted a long-term measurement ...To accurately evaluate the carbon sequestration potential and better elucidate the relationship between the carbon cycle and regional climate change, using eddy covariance system, we conducted a long-term measurement of CO 2 fluxes in the rain-fed winter wheat field of the Chinese Loess Plateau. The results showed that the annual net ecosystem CO 2 exchange （NEE） was （-71.6±5.7） and （-65.3±5.3） g C m-2 y-1 for 2008-2009 and 2009-2010 crop years, respectively, suggesting that the agro-ecosystem was a carbon sink （117.4-126.2 g C m-2 yr-1）. However, after considering the harvested grain, the agro- ecosystem turned into a moderate carbon source. The variations in NEE and ecosystem respiration （R eco ） were sensitive to changes in soil water content （SWC）. When SWC ranged form 0.15 to 0.21 m3 m-3, we found a highly significant relationship between NEE and photosynthetically active radiation （PAR）, and a highly significant relationship between R eco and soil temperature （T s ）. However, the highly significant relationships were not observed when SWC was outside the range of 0.15-0.21 m3 m-3. Further, in spring, the R eco instantly responded to a rapid increase in SWC after effective rainfall events, which could induce 2 to 4-fold increase in daily R eco , whereas the R eco was also inhibited by heavy summer rainfall when soils were saturated. Accumulated R eco in summer fallow period decreased carbon fixed in growing season by 16- 25%, indicating that the period imposed negative impacts on annual carbon sequestration.展开更多
From a critical zone perspective, the present paper aims to present the magnitude of groundwater recharge under different agricultural land-use types, reveal the process of water and solute transport in thick vadose z...From a critical zone perspective, the present paper aims to present the magnitude of groundwater recharge under different agricultural land-use types, reveal the process of water and solute transport in thick vadose zone, evaluate the "time lag" effect of recharge, and underscore the role of thickening vadose zone in recharge. The results indicated that different agricultural land-use types need to be further considered in recharge rate estimate. Under the typical irrigation condition in the piedmont plain, the recharge rate under flood irrigated winter wheat and summer maize(W/M_F), maize(M), non-cultivation(NC), native vegetation(NV), vegetables(V), and orchards(O) is 206.4, 149.7, 194.1, 46.4, 320.0, and 48.6 mm/yr, respectively. In the central plain, the value under W/M_F, M, NC, V, and cotton(C) is 92.8, 50.8, 85.0, 255.5, and 26.5 mm/yr, respectively. Soil water residence time(several years) and groundwater level response time(several months) should be distinguished to further understand the processes of groundwater recharge, because the soil water displacement velocities range from 0.2 to 2.2 m/yr while the rate of wetting front propagation is approximately 47 m/yr in the piedmont plain. The thickening vadose zone would prolong residence time of soil water and contaminant, which could postpone the time of or alleviate groundwater pollution, but have no significant influence on the magnitude of recharge in a long time scale. Recharge coefficient based on shorter time span(e.g. 2 or 3 years) should be used with caution as a parameter for groundwater resources evaluation, because it varies with total water input and target soil depth. Uncertainties in evapotranspiration and other water balance components should be evaluated in recharge estimation and the impact of land-use types on recharge should be emphasized. The critical zone science would greatly improve the understanding of groundwater recharge processes. The results of the present study will be helpful in sustainable groundwater resources management.展开更多
Nitrification and denitrification are two key links of nitrogen flow cycle in soil.N2O and N2,generated from biochemical process of nitrogen,can cause not only the nitrogen losses and reduction of nitrogen use efficie...Nitrification and denitrification are two key links of nitrogen flow cycle in soil.N2O and N2,generated from biochemical process of nitrogen,can cause not only the nitrogen losses and reduction of nitrogen use efficiency,but also the boosted concentration of greenhouse gases,severely endangering the environment.Accordingly,nitrification-denitrification has been more and more concerned from whether an agricultural view,or an environmental one.Referring to the related literatures published at home and abroad in recent years,we overviewed the denitrification-caused N loss and N2O emission in various agro-ecosystems,and based on which we put forward countermeasures to reduce the denitrification-caused N loss and N2O emission and its research prospects in the future.展开更多
Research on carbon cycling has attracted attention from both scientists and policy-makers. Based on material flow analysis, this study systematically budgets the carbon inputs, outputs and balance from 1980 to 2013 fo...Research on carbon cycling has attracted attention from both scientists and policy-makers. Based on material flow analysis, this study systematically budgets the carbon inputs, outputs and balance from 1980 to 2013 for China＇s agro-ecosystem and its sub-systems, including agricultural land use, livestock breeding and rural life. The results show that from 1980 to 2013, both the carbon input and output were growing gradually, with the carbon input doubling from 1.6 Pg C/year in 1980 to 3.4 Pg C/year in 2013, while carbon output grew from 2.2 Pg C/year in 1980 to 3.8 Pg C/year in 2013. From 1980 to 2013, the crop production system in China has remained a carbon source, and the agricultural land uses were also almost all carbon sources instead of carbon sinks. As soil carbon stock plays a very important role in deciding the function of China＇s agro-ecosystem as a carbon sink or source, practices that can promote carbon storage and sequestration will be an essential component of low carbon agriculture development in China.展开更多
On the basis of 'The Statistical Data of Guangdong Province in 1981' and the 14 selected original variables, 107 counties and suburbs in Guangdong are classified. In the classification, cluster analysis is app...On the basis of 'The Statistical Data of Guangdong Province in 1981' and the 14 selected original variables, 107 counties and suburbs in Guangdong are classified. In the classification, cluster analysis is applied, and the cluster hierarchy of the agro-ecosystem is achieved with a computer. According to output level, planting structure, and input level of energy, there is an evident regionalism in the agro-ecosystem of Guangdong, which presents approximately concentric circles centralized by Guangzhou City.展开更多
Using the emergy analysis method,we conduct trend analysis of changes in the total emergy,input and output structure,various emergy indicators of agro-ecosystem in Hunan Province during the period 1999-2008.The result...Using the emergy analysis method,we conduct trend analysis of changes in the total emergy,input and output structure,various emergy indicators of agro-ecosystem in Hunan Province during the period 1999-2008.The results show that during the study period,total emergy input basically remained stable,but the emergy input structure was constantly optimized,of which the input of non-renewable industrial assistant emergy increased by 38.4%,from 4.00E +22 sej to 5.53E +22 sej,and the input of renewable organic emergy declined from 1.32E +23 sej to 1.20E + 23 sej;total emergy yield and yield efficiency of this system were promoted dramatically,and in 2008,the total emergy yield reached 1.69E +23 sej,increasing by 23.8% as against that in 1999,the net emergy yield ratio rose from 0.79 to 0.96;since the environmental loading ratio also tended to rise constantly,from 1.12 to 1.79,the sustainability index of this system also experienced the slow downward trend,from 0.71 to 0.54,always less than 1,indicating that the agriculture in Hunan Province is the high consumption-driven ecosystem in general,with obvious features of extensive development.展开更多
Alternative Land Use Services (ALUS) is an incentive-based program established in Canada to pay farmers for their voluntary delivery of ecosystem services (ES). All seven ALUS programs across the country were examined...Alternative Land Use Services (ALUS) is an incentive-based program established in Canada to pay farmers for their voluntary delivery of ecosystem services (ES). All seven ALUS programs across the country were examined using a standardized case-study approach based on site visits, reading internal documents, attending program meetings, and engaging in semi-structured interviews with program administrators, participating farmers, and advisory board members. Direct content analysis was used to highlight recurrent themes and emerging lessons in relation to the salient particulars of program physical location, administration framework, delivery of ES, and development and receipt by communities. Our three major findings are: 1) Overall, ALUS has been judged by participants to be a very successful program, whose strength is that it is completely voluntary, non-permanent, and readily adaptable to each location’s environmental conditions, economic funding base, and cultural milieu. 2) One serious shortcoming of all ALUS programs is a general lack of quantifiable data on their ability to increase ES. Instead, environmental benefits are either assumed or based on the idea that the areal extent of enrolled land is the sole measure of its environmental worth. 3) It may be that the social impact of ALUS is its greatest success. In this regard, for farmers, it is the process of engaging in land-use decision making and the recognition of their role as environmental stewards that is a bigger motivation for participating in an ALUS program than the modest financial incentives which they receive.展开更多
The European Union （EU） Wild Birds Directive recognises that the most serious threats to wild birds＇ conservation in Europe are habitat loss and degradation, and hence, habitats of threatened and migratory species ...The European Union （EU） Wild Birds Directive recognises that the most serious threats to wild birds＇ conservation in Europe are habitat loss and degradation, and hence, habitats of threatened and migratory species must be protected with the establishment of the network of the special protection areas （SPAs） for migratory and endangered bird species in the EU member states. The major European population of the lesser kestrel Falco naumanni, a migratory falcon listed in Annex I of the Birds Directive, occurs in low-input farming systems in the Mediterranean basin, including Greece. The aim of this study was to identify foraging habitats of lesser kestrels and relate them to the delimited SPAs in the agro-ecosystems of Greece, where the stronghold of the species population for Greece occurs. Foraging habitat preferences were assessed using Poisson regression models （PRMs）. SPAs were examined on whether they can effectively protect foraging habitats for breeding lesser kestrels in the study area. Foraging lesser kestrel abundance was positively associated with grasslands and non-irrigated land （dry cereals）, and negatively associated with irrigated land （wet cotton）, scrubland and woodland. Electricity facilities were used as foraging perches by lesser kestrels. The current SPAs cover a small percentage of the species＇ foraging sites and cannot be considered coherent enough to support and protect the foraging habitats of lesser kestrels and other priority species in the agro-ecosystems of the study area. Proposals for effective conservation of low-input farming systems, supporting priority species, are also presented.展开更多
A research project on interaction between agroecosystems and global change has been accepted as a Category Ⅰ contribution to IGBP-GCTE (International Geosphere-Biosphere Programme-Global Change & Terrestrial Ecos...A research project on interaction between agroecosystems and global change has been accepted as a Category Ⅰ contribution to IGBP-GCTE (International Geosphere-Biosphere Programme-Global Change & Terrestrial Ecosystems) Core Research, the highest-level support GCTE has offered to an individual research project so far. This was confirmed by Prof. Noble, GCTE Chairman, in a letter to Prof. Peng Shaolin, Principal Investigator of展开更多
Topsoil soil organic carbon(SOC) data were collected from long-term Chinese agro-ecosystem experiments presented in 76 reports with measurements over 1977 and 2006.The data set comprised 481 observations(135 rice padd...Topsoil soil organic carbon(SOC) data were collected from long-term Chinese agro-ecosystem experiments presented in 76 reports with measurements over 1977 and 2006.The data set comprised 481 observations(135 rice paddies and 346 dry croplands) of SOC under different fertilization schemes at 70 experimental sites(28 rice paddies and 42 dry croplands).The data set covered 16 dominant soil types found in croplands across 23 provinces of China's Mainland.The fertilization schemes were grouped into six categories:N(inorganic nitrogen fertilizer only),NP(compound inorganic nitrogen and phosphorus fertilizers),NPK(compound inorganic nitrogen,phosphorus and potassium fertilizers),O(organic fertilizers only),OF(combined inorganic/organic fertilization) and Others(other unbalanced fertilizations such as P only,K only,P plus K and N plus K).Relative change in SOC content was analyzed,and rice paddies and dry croplands soils were compared.There was an overall temporal increase in topsoil SOC content,and relative annual change(RAC,g kg-1 yr-1) ranged -0.14-0.60(0.13 on average) for dry cropland soils and -0.12-0.70(0.19 on average) for rice paddies.SOC content increase was higher in rice paddies than in dry croplands.SOC increased across experimental sites,but was higher under organic fertilization and combined organic/inorganic fertilizations than chemical fertilizations.SOC increase was higher under balanced chemical fertilizations with compound N,P and K fertilizers than unbalanced fertilizations such as N only,N plus P,and N plus K.The effects of specific rational fertilizations on SOC increase persisted for 15 years in dry croplands and 20 years in rice paddies,although RAC values decreased generally as the experiment duration increased.Therefore,the extension of rational fertilization in China's croplands may offer a technical option to enhance C sequestration potential and to sustain long-term crop productivity.展开更多
Agriculture under changing climate scenario is facing major challenges of water scarcity and resource imbalances.Crop water productivity(WP)may act as an indicator of crop responses to water limitation.Organic amendme...Agriculture under changing climate scenario is facing major challenges of water scarcity and resource imbalances.Crop water productivity(WP)may act as an indicator of crop responses to water limitation.Organic amendments such as biochar and manure application to soil are suggested for improving soil quality and reducing water requirements from agricultural sector.However,studies exploring the impact of biochar as sole or in combination with organic and/or chemical fertilizers on WP in dry tropical agro-ecosystems are limited.In this study,we observed the effect of rice-husk ash(RHA,biochar)along with farm-yard manure(FYM)and chemical fertilizers(CF)under varying water conditions on soil hydro-physical properties,yield and WP of wheat crop.Water-filled pore space(WFPS),grain and straw yield,irrigation and total water productivity varied significantly(at P<0.001)at treatment level.Grain and straw yield were found higher under sole and combined CF applied treatments.Sole and combined RHA and FYM amendment improved water holding capacity(WHC)and WFPS,whereas a decrease in crop yield was observed as compared to the control.Irrigation and total water productivity were found higher under combined RHA+FYM and sole CF treatments with reduced water supply(except sole CF)as compared to control and sole RHA treatments with full water irrigation.Crop water productivity was found positively correlated with grain and straw yields,however,significant correlations were not observed with WHC and WFPS.Results indicate that increasing soil hydro-physical properties in silty-loam soil may hinder crop yield and WP under sole biochar applied soils.Overall,the implications of the study would help in devising agro-management practices based on combined application of RHA and FYM with reduced chemical fertilizer and water inputs to mitigate the impacts of climate change without compromising crop yield in the highly vulnerable dry tropical agro-ecosystem of India.Moreover,long-term studies are needed in these ecosystems to identify the appropriate agricultural package for mitigating the forthcoming water scarcity conditions.展开更多
基金Supported by Hunan Provincial Situation and Decision Consultation Project (2012BZZ16)National Social Science Fund of China(11BJY029)Youth Fund Project of Central South University of Forestry and Technology(2011ZB003)~~
文摘[Objective] To analyze the efficiency of Hunan agro-ecosystem in 1980- 2010. [Method] This paper adopts the emergy methods to evaluate the emergy input and output. [Result] The growth of total emergy input was mainly caused by the auxiliary factors in this phase. The proportion of the nonrenewable purchased emergy input to the total auxiliary emergy input increased from 21.80% in 1980 to 33.04% in 2010. In 1980-2010 the total emergy output of the system increased by 2.43 times, the proportions of the stock farming emergy output and fishery emergy output to the total emergy output increased sharply, while those of the planting emergy output and forestry emergy output showed a considerable decline. [Conclusion] The emergy yield ratio of this system was improved but its sustainability was worrying.
基金supported by the National Natural Science Foundation of China (31171506 and 31071375)
文摘To accurately evaluate the carbon sequestration potential and better elucidate the relationship between the carbon cycle and regional climate change, using eddy covariance system, we conducted a long-term measurement of CO 2 fluxes in the rain-fed winter wheat field of the Chinese Loess Plateau. The results showed that the annual net ecosystem CO 2 exchange （NEE） was （-71.6±5.7） and （-65.3±5.3） g C m-2 y-1 for 2008-2009 and 2009-2010 crop years, respectively, suggesting that the agro-ecosystem was a carbon sink （117.4-126.2 g C m-2 yr-1）. However, after considering the harvested grain, the agro- ecosystem turned into a moderate carbon source. The variations in NEE and ecosystem respiration （R eco ） were sensitive to changes in soil water content （SWC）. When SWC ranged form 0.15 to 0.21 m3 m-3, we found a highly significant relationship between NEE and photosynthetically active radiation （PAR）, and a highly significant relationship between R eco and soil temperature （T s ）. However, the highly significant relationships were not observed when SWC was outside the range of 0.15-0.21 m3 m-3. Further, in spring, the R eco instantly responded to a rapid increase in SWC after effective rainfall events, which could induce 2 to 4-fold increase in daily R eco , whereas the R eco was also inhibited by heavy summer rainfall when soils were saturated. Accumulated R eco in summer fallow period decreased carbon fixed in growing season by 16- 25%, indicating that the period imposed negative impacts on annual carbon sequestration.
基金National Key Research and Development Plan,No.2016YFC0401403National Natural Science Foundation of China,No.41877169
文摘From a critical zone perspective, the present paper aims to present the magnitude of groundwater recharge under different agricultural land-use types, reveal the process of water and solute transport in thick vadose zone, evaluate the "time lag" effect of recharge, and underscore the role of thickening vadose zone in recharge. The results indicated that different agricultural land-use types need to be further considered in recharge rate estimate. Under the typical irrigation condition in the piedmont plain, the recharge rate under flood irrigated winter wheat and summer maize(W/M_F), maize(M), non-cultivation(NC), native vegetation(NV), vegetables(V), and orchards(O) is 206.4, 149.7, 194.1, 46.4, 320.0, and 48.6 mm/yr, respectively. In the central plain, the value under W/M_F, M, NC, V, and cotton(C) is 92.8, 50.8, 85.0, 255.5, and 26.5 mm/yr, respectively. Soil water residence time(several years) and groundwater level response time(several months) should be distinguished to further understand the processes of groundwater recharge, because the soil water displacement velocities range from 0.2 to 2.2 m/yr while the rate of wetting front propagation is approximately 47 m/yr in the piedmont plain. The thickening vadose zone would prolong residence time of soil water and contaminant, which could postpone the time of or alleviate groundwater pollution, but have no significant influence on the magnitude of recharge in a long time scale. Recharge coefficient based on shorter time span(e.g. 2 or 3 years) should be used with caution as a parameter for groundwater resources evaluation, because it varies with total water input and target soil depth. Uncertainties in evapotranspiration and other water balance components should be evaluated in recharge estimation and the impact of land-use types on recharge should be emphasized. The critical zone science would greatly improve the understanding of groundwater recharge processes. The results of the present study will be helpful in sustainable groundwater resources management.
基金Supported by Key Natural Science Foundation of Fujian Province(2008J0120)Natural Science Foundation of Fujian Province(2006J0009)+1 种基金Non-profit Program from Science and Technology Department of Fujian Province(2009R10032-1 and 2010R1024-2)Special Fund for the Establishment of S&T Innovation Teams in Fujian Academy of Agricultural Sciences from Financial Department of Fujian Province(STIF-Y01)
文摘Nitrification and denitrification are two key links of nitrogen flow cycle in soil.N2O and N2,generated from biochemical process of nitrogen,can cause not only the nitrogen losses and reduction of nitrogen use efficiency,but also the boosted concentration of greenhouse gases,severely endangering the environment.Accordingly,nitrification-denitrification has been more and more concerned from whether an agricultural view,or an environmental one.Referring to the related literatures published at home and abroad in recent years,we overviewed the denitrification-caused N loss and N2O emission in various agro-ecosystems,and based on which we put forward countermeasures to reduce the denitrification-caused N loss and N2O emission and its research prospects in the future.
基金supported by the National Science & Technology Pillar Program during the 12th Five-year Plan Period (No. 2013BAD11B03)the National Natural Science Foundation of China (Nos. 71573260,71273153,and 71525007)the Basic Scientific Research Fund (No. BSRF201311) for National Nonprofit Institutes from Ministry of Agriculture(MoA),China
文摘Research on carbon cycling has attracted attention from both scientists and policy-makers. Based on material flow analysis, this study systematically budgets the carbon inputs, outputs and balance from 1980 to 2013 for China＇s agro-ecosystem and its sub-systems, including agricultural land use, livestock breeding and rural life. The results show that from 1980 to 2013, both the carbon input and output were growing gradually, with the carbon input doubling from 1.6 Pg C/year in 1980 to 3.4 Pg C/year in 2013, while carbon output grew from 2.2 Pg C/year in 1980 to 3.8 Pg C/year in 2013. From 1980 to 2013, the crop production system in China has remained a carbon source, and the agricultural land uses were also almost all carbon sources instead of carbon sinks. As soil carbon stock plays a very important role in deciding the function of China＇s agro-ecosystem as a carbon sink or source, practices that can promote carbon storage and sequestration will be an essential component of low carbon agriculture development in China.
文摘On the basis of 'The Statistical Data of Guangdong Province in 1981' and the 14 selected original variables, 107 counties and suburbs in Guangdong are classified. In the classification, cluster analysis is applied, and the cluster hierarchy of the agro-ecosystem is achieved with a computer. According to output level, planting structure, and input level of energy, there is an evident regionalism in the agro-ecosystem of Guangdong, which presents approximately concentric circles centralized by Guangzhou City.
基金Supported by National Social Science Foundation (11BJY029)Hunan Social Science Fund Project (2010YBB348)+1 种基金Open Fund for Hunan University Innovation Platform (10K080)Key Project of Soft Science in Hunan Province (2011ZK2046)
文摘Using the emergy analysis method,we conduct trend analysis of changes in the total emergy,input and output structure,various emergy indicators of agro-ecosystem in Hunan Province during the period 1999-2008.The results show that during the study period,total emergy input basically remained stable,but the emergy input structure was constantly optimized,of which the input of non-renewable industrial assistant emergy increased by 38.4%,from 4.00E +22 sej to 5.53E +22 sej,and the input of renewable organic emergy declined from 1.32E +23 sej to 1.20E + 23 sej;total emergy yield and yield efficiency of this system were promoted dramatically,and in 2008,the total emergy yield reached 1.69E +23 sej,increasing by 23.8% as against that in 1999,the net emergy yield ratio rose from 0.79 to 0.96;since the environmental loading ratio also tended to rise constantly,from 1.12 to 1.79,the sustainability index of this system also experienced the slow downward trend,from 0.71 to 0.54,always less than 1,indicating that the agriculture in Hunan Province is the high consumption-driven ecosystem in general,with obvious features of extensive development.
文摘Alternative Land Use Services (ALUS) is an incentive-based program established in Canada to pay farmers for their voluntary delivery of ecosystem services (ES). All seven ALUS programs across the country were examined using a standardized case-study approach based on site visits, reading internal documents, attending program meetings, and engaging in semi-structured interviews with program administrators, participating farmers, and advisory board members. Direct content analysis was used to highlight recurrent themes and emerging lessons in relation to the salient particulars of program physical location, administration framework, delivery of ES, and development and receipt by communities. Our three major findings are: 1) Overall, ALUS has been judged by participants to be a very successful program, whose strength is that it is completely voluntary, non-permanent, and readily adaptable to each location’s environmental conditions, economic funding base, and cultural milieu. 2) One serious shortcoming of all ALUS programs is a general lack of quantifiable data on their ability to increase ES. Instead, environmental benefits are either assumed or based on the idea that the areal extent of enrolled land is the sole measure of its environmental worth. 3) It may be that the social impact of ALUS is its greatest success. In this regard, for farmers, it is the process of engaging in land-use decision making and the recognition of their role as environmental stewards that is a bigger motivation for participating in an ALUS program than the modest financial incentives which they receive.
文摘The European Union （EU） Wild Birds Directive recognises that the most serious threats to wild birds＇ conservation in Europe are habitat loss and degradation, and hence, habitats of threatened and migratory species must be protected with the establishment of the network of the special protection areas （SPAs） for migratory and endangered bird species in the EU member states. The major European population of the lesser kestrel Falco naumanni, a migratory falcon listed in Annex I of the Birds Directive, occurs in low-input farming systems in the Mediterranean basin, including Greece. The aim of this study was to identify foraging habitats of lesser kestrels and relate them to the delimited SPAs in the agro-ecosystems of Greece, where the stronghold of the species population for Greece occurs. Foraging habitat preferences were assessed using Poisson regression models （PRMs）. SPAs were examined on whether they can effectively protect foraging habitats for breeding lesser kestrels in the study area. Foraging lesser kestrel abundance was positively associated with grasslands and non-irrigated land （dry cereals）, and negatively associated with irrigated land （wet cotton）, scrubland and woodland. Electricity facilities were used as foraging perches by lesser kestrels. The current SPAs cover a small percentage of the species＇ foraging sites and cannot be considered coherent enough to support and protect the foraging habitats of lesser kestrels and other priority species in the agro-ecosystems of the study area. Proposals for effective conservation of low-input farming systems, supporting priority species, are also presented.
文摘A research project on interaction between agroecosystems and global change has been accepted as a Category Ⅰ contribution to IGBP-GCTE (International Geosphere-Biosphere Programme-Global Change & Terrestrial Ecosystems) Core Research, the highest-level support GCTE has offered to an individual research project so far. This was confirmed by Prof. Noble, GCTE Chairman, in a letter to Prof. Peng Shaolin, Principal Investigator of
基金supported by the National Natural Science Foundation of China (Grant No. 40710019002)the Ministry of Science and Technology of China (Grant No. 2008BAD95B13-1)the Ministry of Education of China for key basic research projects
文摘Topsoil soil organic carbon(SOC) data were collected from long-term Chinese agro-ecosystem experiments presented in 76 reports with measurements over 1977 and 2006.The data set comprised 481 observations(135 rice paddies and 346 dry croplands) of SOC under different fertilization schemes at 70 experimental sites(28 rice paddies and 42 dry croplands).The data set covered 16 dominant soil types found in croplands across 23 provinces of China's Mainland.The fertilization schemes were grouped into six categories:N(inorganic nitrogen fertilizer only),NP(compound inorganic nitrogen and phosphorus fertilizers),NPK(compound inorganic nitrogen,phosphorus and potassium fertilizers),O(organic fertilizers only),OF(combined inorganic/organic fertilization) and Others(other unbalanced fertilizations such as P only,K only,P plus K and N plus K).Relative change in SOC content was analyzed,and rice paddies and dry croplands soils were compared.There was an overall temporal increase in topsoil SOC content,and relative annual change(RAC,g kg-1 yr-1) ranged -0.14-0.60(0.13 on average) for dry cropland soils and -0.12-0.70(0.19 on average) for rice paddies.SOC content increase was higher in rice paddies than in dry croplands.SOC increased across experimental sites,but was higher under organic fertilization and combined organic/inorganic fertilizations than chemical fertilizations.SOC increase was higher under balanced chemical fertilizations with compound N,P and K fertilizers than unbalanced fertilizations such as N only,N plus P,and N plus K.The effects of specific rational fertilizations on SOC increase persisted for 15 years in dry croplands and 20 years in rice paddies,although RAC values decreased generally as the experiment duration increased.Therefore,the extension of rational fertilization in China's croplands may offer a technical option to enhance C sequestration potential and to sustain long-term crop productivity.
文摘Agriculture under changing climate scenario is facing major challenges of water scarcity and resource imbalances.Crop water productivity(WP)may act as an indicator of crop responses to water limitation.Organic amendments such as biochar and manure application to soil are suggested for improving soil quality and reducing water requirements from agricultural sector.However,studies exploring the impact of biochar as sole or in combination with organic and/or chemical fertilizers on WP in dry tropical agro-ecosystems are limited.In this study,we observed the effect of rice-husk ash(RHA,biochar)along with farm-yard manure(FYM)and chemical fertilizers(CF)under varying water conditions on soil hydro-physical properties,yield and WP of wheat crop.Water-filled pore space(WFPS),grain and straw yield,irrigation and total water productivity varied significantly(at P<0.001)at treatment level.Grain and straw yield were found higher under sole and combined CF applied treatments.Sole and combined RHA and FYM amendment improved water holding capacity(WHC)and WFPS,whereas a decrease in crop yield was observed as compared to the control.Irrigation and total water productivity were found higher under combined RHA+FYM and sole CF treatments with reduced water supply(except sole CF)as compared to control and sole RHA treatments with full water irrigation.Crop water productivity was found positively correlated with grain and straw yields,however,significant correlations were not observed with WHC and WFPS.Results indicate that increasing soil hydro-physical properties in silty-loam soil may hinder crop yield and WP under sole biochar applied soils.Overall,the implications of the study would help in devising agro-management practices based on combined application of RHA and FYM with reduced chemical fertilizer and water inputs to mitigate the impacts of climate change without compromising crop yield in the highly vulnerable dry tropical agro-ecosystem of India.Moreover,long-term studies are needed in these ecosystems to identify the appropriate agricultural package for mitigating the forthcoming water scarcity conditions.
