Carbon sequestration in agricultural soils is a complex process controlled by farming practices, climate and some other environment factors. Since purple soils are unique in China and used as the main cropland in Sich...Carbon sequestration in agricultural soils is a complex process controlled by farming practices, climate and some other environment factors. Since purple soils are unique in China and used as the main cropland in Sichuan Basin of China, it is of great importance to study and understand the impacts of different fertilizer amendments on soil organic carbon（SOC） changes with time. A research was carried out to investigate the relationship between soil carbon sequestration and organic carbon input as affected by different fertilizer treatments at two long-term rice-based cropping system experiments set up in early 1980 s. Each experiment consisted of six identical treatments, including（1） no fertilizer（CK）,（2） nitrogen and phosphorus fertilizers（NP）,（3） nitrogen, phosphorus and potassium fertilizers（NPK）,（4） fresh pig manure（M）,（5） nitrogen and phosphorus fertilizers plus manure（MNP）, and（6） nitrogen, phosphorus and potassium fertilizers plus manure（MNPK）. The results showed that annual harvestable carbon biomass was the highest in the treatment of MNPK, followed by MNP and NPK, then M and NP, and the lowest in CK. Most of fertilizer treatments resulted in a significant gain in SOC ranging from 6.48 to 2 9.13% compared with the CK, and raised soil carbon sequestration rate to 0.10–0.53 t ha–1 yr-1. Especially, addition of manure on the basis of mineral fertilizers was very conducive to SOC maintenance in this soil. SOC content and soil carbon sequestration rate under balanced fertilizer treatments（NPK and MNPK） in the calcareous purple soil（Suining） were higher than that in the acid purple soil（Leshan）. But carbon conversion rate at Leshan was 11.00%, almost 1.5 times of that（7.80%） at Suining. Significant linear correlations between soil carbon sequestration and carbon input were observed at both sites, signifying that the purple soil was not carbon-saturated and still had considerable potential to se questrate more carbon.展开更多
A long-term simulation experiment was carried out to study the effect of rice-based cropping system,green manure and ground-water level on soil organic matter. Soil organic matter content increased when upland soil wa...A long-term simulation experiment was carried out to study the effect of rice-based cropping system,green manure and ground-water level on soil organic matter. Soil organic matter content increased when upland soil was puddled and cropped under submerged conditions. Among all treatments, soil organic matter contents in the treatments of rice-rice-flooded fallow in winter (WF) were the highest, those in the treatments of rice-rice-astragalus (WG) came the second, and those in the treatments of rice-rice-rape (WR)were the lowest. At the same rate of green manure application, the degrees of organo-mineral complexing in soils of treatments WG and WR were higher than those of treatment WF. After 9-year rice cultivation, the state of combination of humus in heavy fraction varied with treatments. The relative content of loosely bonded humus decreased in the order of WR > WG > WF, and it correlated significantly with Se availability.展开更多
This paper traces the origins and achievements of the R^seau Ouest et Centre Africain du Riz--ROCARIZ （West and Central Africa Rice Research and Development Network）. The ROCARIZ institutional arrangement showed tha...This paper traces the origins and achievements of the R^seau Ouest et Centre Africain du Riz--ROCARIZ （West and Central Africa Rice Research and Development Network）. The ROCARIZ institutional arrangement showed that rice science is approached from multi-stakeholder perspectives that place end users and entrepreneurs at the center of research for development, and collaboration among rice-based stakeholders can be enhanced and sustained. The ROCARIZ used competitive research grants through multi-stakeholder task forces to generate, adapt, and facilitate the adoption of rice-based technologies and approaches by resource poor households. The grants contributed to： （1） farmer adoption of high yielding and multiple stress resilient lowland NERICAs （New Rices for Africa） （NERICA-L）; （2） producer access to credit and services resulting in increased marketing of quality seed rice, paddy, and grain rice by farmer entrepreneurs and poor rural households; （3） improved skills of stakeholders on the use of impact assessment tools to demonstrate adoption of rice-based technologies; （4） enhanced skills of rice breeders in molecular assisted marker selection to shorten the varietal development process; and （S） experiential learning and sharing to improve access to information and knowledge.展开更多
Under small and marginal farm conditions,allocation of land exclusively for forages is not possible.Hence,integration of forages in existing crop geometry can ensure production of grain and fodder,simultaneously under...Under small and marginal farm conditions,allocation of land exclusively for forages is not possible.Hence,integration of forages in existing crop geometry can ensure production of grain and fodder,simultaneously under rainfed conditions.Afield experiment was conducted to study the effect of different nutrient management practices on rice and fodder intercropping systems under rainfed conditions during 2015-2017.The intercropping system comprised(i)sole rice(R),(ii)rice and cowpea(5:2)(CP)and(iii)rice and ricebean(5:2)(RB)whereas the different nutrient management practices comprised(i)application of farm yard manure(FYM)at 5t ha^(-1)(farmers'practice)(N_(1)),(ii)application of inorganic fertilizer(recommended dose of fertilizer(RDF)of rice,60:30:30 kg ha^(-1) of N:P_(2)O_(5):K_(2)O)(N_(2))and(iii)application of both FYM at 5t ha^(-1) and 50%of RDF inorganic fertilizer(N3).The results of the experiment revealed that the growth attribute such as leaf area was influenced significantly when fodder crops were taken as intercrops because rice plant was getting more nitrogen from soil due to nitrogen fixation of leguminous fodder crops.Among the nutrient management practices,significant differences in leaf area were found beween N2 and and between N_(3)and N_(1)treatments.However,regarding total number of effective tillers,significant differences were found neither between nutrient management practices nor between cropping systems.The rice equivalent yield(REY)based on price(REY_(P))was found to be significantly lower in CP(2615 kg ha^(-1);-6.4%)and RB intercropping systems(2571 kg ha^(-1);-8.0%)than in R monocropping system(2794 kg ha^(-1)).However,the REY based on energy(REY_(E))of CP(2999 kg ha^(-1);+7.3%)and RB(2960 kg ha^(-1);+5.9%)were found to be significantly higher than that of R(2794 kg ha^(-1))irrespective of nutrient management practices.Between different nutrient management practices,the N3 treatment recorded the highest REY_(P)and REY_(E)which was at par with the N_(2)treatment and significantly higher than the N1 treatment irrespective of cropping systems.The combined application of both organic and inorganic sources of nutrients helped to supply nutrients throughout the growing season,which led to improved growth parameters and rice yield.The R monocropping system resulted in more income and rain water use efficiency(RWUE)closely followed by rice and fodder intercropping systems.However,the REYe and energy use efficiency(EUE)of rice and fodder intercropping systems were higher than those of R.Also,fodder helped to meet the requirement of cattle feeding in the off-season.Hence,the intercropping system is advocated in the study zone.Further study can be done on ecosystem services and carbon sequestration potential of the intercropping system,as well as the system's coping ability in response to short drought through observing periodic soil moisture regime in root zone.展开更多
基金financially supported by the Special Fund for Agro-scientific Research in the Public Interest of China(201203030)the National Natural Science Foundation of China(41201295)+1 种基金the Financial Fund for Young Scholars of Sichuan Academy of Agricultural SciencesChina(2014QNJJ-014)
文摘Carbon sequestration in agricultural soils is a complex process controlled by farming practices, climate and some other environment factors. Since purple soils are unique in China and used as the main cropland in Sichuan Basin of China, it is of great importance to study and understand the impacts of different fertilizer amendments on soil organic carbon（SOC） changes with time. A research was carried out to investigate the relationship between soil carbon sequestration and organic carbon input as affected by different fertilizer treatments at two long-term rice-based cropping system experiments set up in early 1980 s. Each experiment consisted of six identical treatments, including（1） no fertilizer（CK）,（2） nitrogen and phosphorus fertilizers（NP）,（3） nitrogen, phosphorus and potassium fertilizers（NPK）,（4） fresh pig manure（M）,（5） nitrogen and phosphorus fertilizers plus manure（MNP）, and（6） nitrogen, phosphorus and potassium fertilizers plus manure（MNPK）. The results showed that annual harvestable carbon biomass was the highest in the treatment of MNPK, followed by MNP and NPK, then M and NP, and the lowest in CK. Most of fertilizer treatments resulted in a significant gain in SOC ranging from 6.48 to 2 9.13% compared with the CK, and raised soil carbon sequestration rate to 0.10–0.53 t ha–1 yr-1. Especially, addition of manure on the basis of mineral fertilizers was very conducive to SOC maintenance in this soil. SOC content and soil carbon sequestration rate under balanced fertilizer treatments（NPK and MNPK） in the calcareous purple soil（Suining） were higher than that in the acid purple soil（Leshan）. But carbon conversion rate at Leshan was 11.00%, almost 1.5 times of that（7.80%） at Suining. Significant linear correlations between soil carbon sequestration and carbon input were observed at both sites, signifying that the purple soil was not carbon-saturated and still had considerable potential to se questrate more carbon.
文摘A long-term simulation experiment was carried out to study the effect of rice-based cropping system,green manure and ground-water level on soil organic matter. Soil organic matter content increased when upland soil was puddled and cropped under submerged conditions. Among all treatments, soil organic matter contents in the treatments of rice-rice-flooded fallow in winter (WF) were the highest, those in the treatments of rice-rice-astragalus (WG) came the second, and those in the treatments of rice-rice-rape (WR)were the lowest. At the same rate of green manure application, the degrees of organo-mineral complexing in soils of treatments WG and WR were higher than those of treatment WF. After 9-year rice cultivation, the state of combination of humus in heavy fraction varied with treatments. The relative content of loosely bonded humus decreased in the order of WR > WG > WF, and it correlated significantly with Se availability.
文摘This paper traces the origins and achievements of the R^seau Ouest et Centre Africain du Riz--ROCARIZ （West and Central Africa Rice Research and Development Network）. The ROCARIZ institutional arrangement showed that rice science is approached from multi-stakeholder perspectives that place end users and entrepreneurs at the center of research for development, and collaboration among rice-based stakeholders can be enhanced and sustained. The ROCARIZ used competitive research grants through multi-stakeholder task forces to generate, adapt, and facilitate the adoption of rice-based technologies and approaches by resource poor households. The grants contributed to： （1） farmer adoption of high yielding and multiple stress resilient lowland NERICAs （New Rices for Africa） （NERICA-L）; （2） producer access to credit and services resulting in increased marketing of quality seed rice, paddy, and grain rice by farmer entrepreneurs and poor rural households; （3） improved skills of stakeholders on the use of impact assessment tools to demonstrate adoption of rice-based technologies; （4） enhanced skills of rice breeders in molecular assisted marker selection to shorten the varietal development process; and （S） experiential learning and sharing to improve access to information and knowledge.
基金The authors are thankful to the All India Coordinated Research Project for Dryland Agriculture(AICRPDA)Indian Council of Agricultural Research-Central Research Institute for Dryland Agriculture(ICAR-CRIDA)Hyderabad,India and Odisha University of Agriculture and Technology(OUAT),Bhubaneswar,Odisha,India for their financial assistance for conducting the research work.
文摘Under small and marginal farm conditions,allocation of land exclusively for forages is not possible.Hence,integration of forages in existing crop geometry can ensure production of grain and fodder,simultaneously under rainfed conditions.Afield experiment was conducted to study the effect of different nutrient management practices on rice and fodder intercropping systems under rainfed conditions during 2015-2017.The intercropping system comprised(i)sole rice(R),(ii)rice and cowpea(5:2)(CP)and(iii)rice and ricebean(5:2)(RB)whereas the different nutrient management practices comprised(i)application of farm yard manure(FYM)at 5t ha^(-1)(farmers'practice)(N_(1)),(ii)application of inorganic fertilizer(recommended dose of fertilizer(RDF)of rice,60:30:30 kg ha^(-1) of N:P_(2)O_(5):K_(2)O)(N_(2))and(iii)application of both FYM at 5t ha^(-1) and 50%of RDF inorganic fertilizer(N3).The results of the experiment revealed that the growth attribute such as leaf area was influenced significantly when fodder crops were taken as intercrops because rice plant was getting more nitrogen from soil due to nitrogen fixation of leguminous fodder crops.Among the nutrient management practices,significant differences in leaf area were found beween N2 and and between N_(3)and N_(1)treatments.However,regarding total number of effective tillers,significant differences were found neither between nutrient management practices nor between cropping systems.The rice equivalent yield(REY)based on price(REY_(P))was found to be significantly lower in CP(2615 kg ha^(-1);-6.4%)and RB intercropping systems(2571 kg ha^(-1);-8.0%)than in R monocropping system(2794 kg ha^(-1)).However,the REY based on energy(REY_(E))of CP(2999 kg ha^(-1);+7.3%)and RB(2960 kg ha^(-1);+5.9%)were found to be significantly higher than that of R(2794 kg ha^(-1))irrespective of nutrient management practices.Between different nutrient management practices,the N3 treatment recorded the highest REY_(P)and REY_(E)which was at par with the N_(2)treatment and significantly higher than the N1 treatment irrespective of cropping systems.The combined application of both organic and inorganic sources of nutrients helped to supply nutrients throughout the growing season,which led to improved growth parameters and rice yield.The R monocropping system resulted in more income and rain water use efficiency(RWUE)closely followed by rice and fodder intercropping systems.However,the REYe and energy use efficiency(EUE)of rice and fodder intercropping systems were higher than those of R.Also,fodder helped to meet the requirement of cattle feeding in the off-season.Hence,the intercropping system is advocated in the study zone.Further study can be done on ecosystem services and carbon sequestration potential of the intercropping system,as well as the system's coping ability in response to short drought through observing periodic soil moisture regime in root zone.
