Current nitrogen (N) leaching losses and their responses to monthly N additions were investigated under a disturbed pine (Pinus massoniana) forest and a mature monsoon broadleaf forest in southern China. N leaching lo...Current nitrogen (N) leaching losses and their responses to monthly N additions were investigated under a disturbed pine (Pinus massoniana) forest and a mature monsoon broadleaf forest in southern China. N leaching losses from both disturbed and mature forests were quite high (14.6 and 29.2 kg N ha-1 year-1, respectively), accounting for 57% and 80% of their corresponding atmospheric N inputs. N leaching losses were substantially increased following the first 1.5 years of N applications in both forests. The average increases induced by the addition of 50 and 100 kg N ha-1 year-1 were 36.5 and 24.9 kg N ha-1 year-1, respectively, in the mature forest, accounting for 73.0% and 24.9% of the annual amount of N added, and 14.2 and 16.8 kg N ha-1 year-1 in the disturbed forest, accounting for 28.4% and 16.8% of the added N. Great N leaching and a fast N leaching response to N additions in the mature forest might result from long-term N accumulation and high ambient N deposition load (greater than 30 kg N ha-1 year-1 over the past 15 years), whereas in the disturbed forest, it might result from the human disturbance and high ambient N deposition load. These results suggest that both disturbed and mature forests in the study region may be sensitive to increasing N deposition.展开更多
Ammonia(NH3)emissions,the most important nitrogen(N)loss form,always induce a series of environmental problems such as increased frequency of regional haze pollution,accelerated N deposition,and N eutrophication.Arbus...Ammonia(NH3)emissions,the most important nitrogen(N)loss form,always induce a series of environmental problems such as increased frequency of regional haze pollution,accelerated N deposition,and N eutrophication.Arbuscular mycorrhizal(AM)fungi play key roles in N cycling.However,it is still unclear whether AM fungi can alleviate N losses by reducing NH3emissions.The potential mechanisms by which AM fungi reduce NH_(3)emissions in five land-use types(grazed grassland,mowed grassland,fenced grassland,artificial alfalfa grassland,and cropland)were explored in this study.Results showed that AM fungal inoculation significantly reduced NH3emissions,and the mycorrhizal responses of NH3emissions were determined by land-use type.Structural equation modeling(SEM)showed that AM fungi and land-use type directly affected NH_(3)emissions.In addition,the reduction in NH_(3)emissions was largely driven by the decline in soil NH_(4)^(+)-N and pH and the increases in abundances of ammonia-oxidizing archaea(AOA)amoA and bacteria(AOB)amoB genes,urease activity,and plant N uptake induced by AM fungal inoculation and land-use type.The present results highlight that reducing the negative influence of agricultural intensification caused by land-use type changes on AM fungi should be considered to reduce N losses in agriculture and grassland ecosystems.展开更多
[Objective] The study aimed at comparing the characteristics of nutrient release from coated controlled/slow-release fertilizers,so as to provide theoretical reference for improving the farming practice and fertilizer...[Objective] The study aimed at comparing the characteristics of nutrient release from coated controlled/slow-release fertilizers,so as to provide theoretical reference for improving the farming practice and fertilizer application,reducing pollution in Baiyangdian Lake and the surrounding area.[Method] Soil column leaching method was used to study NH4-N and NO3-N leaching characteristics from five kinds of nitrogen fertilizers including three coated controlled/slow-release fertilizers.[Result] Resin and sulfur coated controlled/slow-release urea decreased NH4-N concentration obviously,controlled NO3-N release in early term of experiment,while increased the content of NH4-N ＋ NO3-N in middle-late periods.Compared with that of common urea,the NH4-N of resin and sulfur coated controlled/slow-release urea decreased by 98.5%,98.7% in early period,96.5%,97.4% in middle period,and 59.1%,81.75% in last period.[Conclusion] Resin and sulfur coated controlled/slow-release urea significantly reduced the NH4-N concentration,effectively controlled the NO3-N release in early stage and increased the supply of NO3-N in last period.展开更多
基金supported by the National Natural Science Foundation of China (No.30670392)the Knowledge InnovationProgram of the Chinese Academy of Sciences (Nos.KZCX2-YW-432-2 and KSCX2-SW-133).
文摘Current nitrogen (N) leaching losses and their responses to monthly N additions were investigated under a disturbed pine (Pinus massoniana) forest and a mature monsoon broadleaf forest in southern China. N leaching losses from both disturbed and mature forests were quite high (14.6 and 29.2 kg N ha-1 year-1, respectively), accounting for 57% and 80% of their corresponding atmospheric N inputs. N leaching losses were substantially increased following the first 1.5 years of N applications in both forests. The average increases induced by the addition of 50 and 100 kg N ha-1 year-1 were 36.5 and 24.9 kg N ha-1 year-1, respectively, in the mature forest, accounting for 73.0% and 24.9% of the annual amount of N added, and 14.2 and 16.8 kg N ha-1 year-1 in the disturbed forest, accounting for 28.4% and 16.8% of the added N. Great N leaching and a fast N leaching response to N additions in the mature forest might result from long-term N accumulation and high ambient N deposition load (greater than 30 kg N ha-1 year-1 over the past 15 years), whereas in the disturbed forest, it might result from the human disturbance and high ambient N deposition load. These results suggest that both disturbed and mature forests in the study region may be sensitive to increasing N deposition.
基金supported by the National Natural Science Foundation of China(Nos.32171645 and 31770359)the Foundation of Science and Technology Commission of Jilin Province,China(No.20200201115JC)the Fundamental Research Funds for the Central Universities,China(No.2412020ZD010)。
文摘Ammonia(NH3)emissions,the most important nitrogen(N)loss form,always induce a series of environmental problems such as increased frequency of regional haze pollution,accelerated N deposition,and N eutrophication.Arbuscular mycorrhizal(AM)fungi play key roles in N cycling.However,it is still unclear whether AM fungi can alleviate N losses by reducing NH3emissions.The potential mechanisms by which AM fungi reduce NH_(3)emissions in five land-use types(grazed grassland,mowed grassland,fenced grassland,artificial alfalfa grassland,and cropland)were explored in this study.Results showed that AM fungal inoculation significantly reduced NH3emissions,and the mycorrhizal responses of NH3emissions were determined by land-use type.Structural equation modeling(SEM)showed that AM fungi and land-use type directly affected NH_(3)emissions.In addition,the reduction in NH_(3)emissions was largely driven by the decline in soil NH_(4)^(+)-N and pH and the increases in abundances of ammonia-oxidizing archaea(AOA)amoA and bacteria(AOB)amoB genes,urease activity,and plant N uptake induced by AM fungal inoculation and land-use type.The present results highlight that reducing the negative influence of agricultural intensification caused by land-use type changes on AM fungi should be considered to reduce N losses in agriculture and grassland ecosystems.
基金Supported by Knowledge Innovation Project of the Chinese Academy of Sciences(KZCX2-YW-449)~~
文摘[Objective] The study aimed at comparing the characteristics of nutrient release from coated controlled/slow-release fertilizers,so as to provide theoretical reference for improving the farming practice and fertilizer application,reducing pollution in Baiyangdian Lake and the surrounding area.[Method] Soil column leaching method was used to study NH4-N and NO3-N leaching characteristics from five kinds of nitrogen fertilizers including three coated controlled/slow-release fertilizers.[Result] Resin and sulfur coated controlled/slow-release urea decreased NH4-N concentration obviously,controlled NO3-N release in early term of experiment,while increased the content of NH4-N ＋ NO3-N in middle-late periods.Compared with that of common urea,the NH4-N of resin and sulfur coated controlled/slow-release urea decreased by 98.5%,98.7% in early period,96.5%,97.4% in middle period,and 59.1%,81.75% in last period.[Conclusion] Resin and sulfur coated controlled/slow-release urea significantly reduced the NH4-N concentration,effectively controlled the NO3-N release in early stage and increased the supply of NO3-N in last period.
