[Objective] Nitrogen and phosphorus losses of surface runoff in various crop rotation systems in the north of Erhai Lake basin were studied with the objective to provide references for risk evaluation of environmental...[Objective] Nitrogen and phosphorus losses of surface runoff in various crop rotation systems in the north of Erhai Lake basin were studied with the objective to provide references for risk evaluation of environmental pollution and formulating countermeasures to control the nonpoint source pollution from agriculture.[Method] Water samples collected in four typical crop rotation systems distributed in seven towns（townships） in the north of Erhai Lake basin were investigated,as well as the fertilizer input,to explore the dynamic change of nitrogen and phosphorus content in surface water of farmland and ditch water,and the correlation between fertilizer input and the concentrations of nitrogen and phosphorus in the surface water of farmland and in the ditch water.[Result] The results showed that nitrogen loss in surface water of farmland in different crop rotation systems differed greatly,and the risk of nitrogen loss was 38% lower in broad bean-rice crop rotation than that in garlic-rice crop rotation.The water soluble nitrogen was the primary form of nitrogen loss.The content of water soluble nitrogen was significantly higher in garlic-rice crop rotation than that in the other rotation systems,and the concentrations of nitrogen in the surface water of farmland in different crop rotation systems followed the sequence below：garlic-rice crop rotationryegrass-rice crop rotationbroad bean-rice crop rotationrape-rice crop rotation.The loss of phosphorus in the surface water of farmland was relatively low and phosphorus combined with silt was the primary form for phosphorus loss.There was no significant difference of the loss of various forms of phosphorus in different crop rotation systems.The contents of total nitrogen and total phosphorus in the surface water of farmland were higher than that in ditch water,with increasing rates of total nitrogen and total phosphorus in ditch water of 72% and 82%,respectively.Topdressing was the critical reason for the high concentrations of nitrogen and phosphorus in the surface water,which also caused the increasing load to the ditch water.[Conclusion] Both the nitrogen and phosphorus loss were the highest in garlic-rice crop rotation.Reasonable crop rotation systems should be established based on both the environmental and economic benefits.This study provided references for controlling the nonpoint source pollution of farmland and improving the water quality of Erhai Lake.展开更多
Guanting Reservoir, one of the drinking water supply sources of Beijing, suffers from water eutrophication. It is mainly supplied by Guishui River. Thus, to investigate the reasons of phosphorus （P） loss and improve...Guanting Reservoir, one of the drinking water supply sources of Beijing, suffers from water eutrophication. It is mainly supplied by Guishui River. Thus, to investigate the reasons of phosphorus （P） loss and improve the P management strategies in Guishui River watershed are important for the safety of drinking water in this region. In this study, a Revised Field P Ranking Scheme （PRS） was developed to reflect the field vulnerability of P loss at the field scale based on the Field PRS. In this new scheme, six factors are included, and each one was assigned a relative weight and a determination method. The affecting factors were classified into transport factors and source factors, and, the standards of environmental quality on surface water and soil erosion classification and degradation of the China were used in this scheme. By the new scheme, thirty-four fields in the Guishui River were categorized as ＂low＂, ＂medium＂ or ＂high＂ potential for P loss into the runoff. The results showed that the P loss risks of orchard and vegetable fields were higher than that of corn and soybean fields. The source factors were the main factors to affect P loss from the study area. In the study area, controlling P input and improving P usage efficiency are critical to decrease P loss. Based on the results, it was suggested that more attention should be paid on the fields of vegetable and orchard since they have extremely high usage rate of P and high soil test of P. Compared with P surplus by field measurements, the Revised Field PRS was more suitable for reflecting the characteristics of fields, and had higher potential capacity to identify critical source areas of P loss than PRS.展开更多
A field experiment was carried out to evaluate the effects of drip fertigation combined with plant hedgerows on nitrogen and phosphorus runoff losses in intensive pear orchards in the Tai Lake Basin.Nitrogen and phosp...A field experiment was carried out to evaluate the effects of drip fertigation combined with plant hedgerows on nitrogen and phosphorus runoff losses in intensive pear orchards in the Tai Lake Basin.Nitrogen and phosphorus runoff over a whole year were measured by using successional runoff water collection devices.The four experimental treatments were conventional fertilization(CK),drip fertigation(DF),conventional fertilization combined with plant hedgerows(C+H),and drip fertigation combined with plant hedgerows(D+H).The results from one year of continuous monitoring showed a significant positive correlation between precipitation and surface runoff discharge.Surface runoff discharge under the treatments without plant hedgerows totaled 15.86%of precipitation,while surface runoff discharge under the treatments with plant hedgerows totaled 12.82%of precipitation.Plant hedgerows reduced the number of runoff events and the amount of surface runoff.Precipitation is the main driving force for the loss of nitrogen and phosphorus in surface runoff,and fertilization is an important factor affecting the losses of nitrogen and phosphorus.In CK,approximately 7.36%of nitrogen and 2.63%of phosphorus from fertilization entered the surface water through runoff.Drip fertigation reduced the accumulation of nitrogen and phosphorus in the surface soil and lowered the runoff loss concentrations of total nitrogen(TN)and total phosphorus(TP).Drip fertigation combined with plant hedgerows significantly reduced the overall TN and TP losses by 45.38 and 36.81%,respectively,in comparison to the CK totals.Drip fertigation increased the vertical migration depth of nitrogen and phosphorus nutrients and reduced the accumulation of nitrogen and phosphorus in the surface soil,which increased the pear yield.The promotion of drip fertigation combined with plant hedgerows will greatly reduce the losses of nitrogen and phosphorus to runoff and maintain the high fruit yields in the intensive orchards of the Tai Lake Basin.展开更多
Phosphorus（P） losses from agricultural soils contribute to eutrophication of surface waters. This field plot study investigated effects of rainfall regimes and P applications on P loss by surface runoff from rice（O...Phosphorus（P） losses from agricultural soils contribute to eutrophication of surface waters. This field plot study investigated effects of rainfall regimes and P applications on P loss by surface runoff from rice（Oryza sativa L.） and wheat（Triticum aestivum L.） cropping systems in Lake Taihu region, China. The study was conducted on two types of paddy soils（Hydromorphic at Anzhen site, Wuxi City, and Degleyed at Xinzhuang site, Changshu City, Jiangsu Province） with different P status, and it covered 3 years with low, high and normal rainfall regimes. Four rates of mineral P fertilizer, i.e., no P（control）, 30 kg P ha^（–1） for rice and 20 kg P ha^（–1） for wheat（P_（30＋20））, 75 plus 40（P_（75＋40））, and 150 plus 80（P_（150＋80））, were applied as treatments. Runoff water from individual plots and runoff events was recorded and analyzed for total P and dissolved reactive P concentrations. Losses of total P and dissolved reactive P significantly increased with rainfall depth and P rates（P〈0.0001）. Annual total P losses ranged from 0.36–0.92 kg ha^–1 in control to 1.13–4.67 kg ha^–1 in P150＋80 at Anzhen, and correspondingly from 0.36–0.48 kg h^–1 to 1.26–1.88 kg ha^–1 at Xinzhuang, with 16–49% of total P as dissolved reactive P. In particular, large amounts of P were lost during heavy rainfall events that occurred shortly after P applications at Anzhen. On average of all P treatments, rice growing season constituted 37–86% of annual total P loss at Anzhen and 28–44% of that at Xinzhuang. In both crop seasons, P concentrations peaked in the first runoff events and decreased with time. During rice growing season, runoff P concentrations positively correlated（P〈0.0001） with P concentrations in field ponding water that was intentionally enclosed by construction of field bund. The relative high P loss during wheat growing season at Xinzhuang was due to high soil P status. In conclusion, P should be applied at rates balancing crop removal（20–30 kg P ha^–1 in this study） and at time excluding heavy rains. Moreover, irrigation and drainage water should be appropriately managed to reduce runoff P losses from rice-wheat cropping systems.展开更多
To achieve the purpose of reducing farm non-point source pollution, we integrated site specific nitrogen management precise irrigation, controlled drainage, and wetland eco-repair system in dike area of Taihu basin. D...To achieve the purpose of reducing farm non-point source pollution, we integrated site specific nitrogen management precise irrigation, controlled drainage, and wetland eco-repair system in dike area of Taihu basin. During investigation, it had given prominence for the water and fertilizer coupling effects of precise irrigation and site specific nutrient management, the characteristics of integration on controlled irrigation, controlled drainage and wetland ecosystem non-point source pollution control. Then the water and fertilizer integrated management mode of paddy field was put forward in Taihu basin where the water production efficiency increased to 1.64 kg. m-3, water saved 37.8%, fertilizer use efficiency raised 15,4%, yield raised 10%, and N, P load decreased 26%-72%. The modern agricultural and farmland ecosystems that control and cut down the farm non-point source pollution came into being, which can be a reference by Taihu basin to control its agricultural non-point source pollution and eutrophicated water body.展开更多
Maintaining drinking water security is a global issue,and phosphorus is a limiting factor affecting drinking water quality.Hence,this study took Fushi Reservoir as a test area,and set up field runoff observation plots...Maintaining drinking water security is a global issue,and phosphorus is a limiting factor affecting drinking water quality.Hence,this study took Fushi Reservoir as a test area,and set up field runoff observation plots around the reservoir catchment,which is covered by moso bamboo stands.Through field observation,the vertical variation of phosphorus loss in different stands of moso bamboo was initially studied.The results showed that:(1)For the vertical dimensions(atmospheric rainfall,stemflow,throughfall,surface runoff)from high to low,the loss of total phosphorus(TP)increased,and the pro-portion of dissolved phosphorus increased from 29.29%(atmospheric rainfall)to 62.76%(surface runoff).(2)Different rainfall factors had various impacts on phosphorus loss at the different vertical levels.The accumulation of rainfall had the greatest impact on surface runoff TP loss,with the correlation coefficient reaching 0.994(P<0.01),while surface runoff particulate phosphorus loss was mostly affected by the average rainfall intensity.(3)Modifying the forest structure in water source areas can reduce the loss of TP via stemflow and throughfall,but the effect on surface runoff TP loss is variable.Thus,it is expected that this novel study can serve as a reference for improving the environmental quality of water source areas,and help in reducing phosphorus loss and controlling non-point source pollution.展开更多
[Objective] The aim was to study on effects of controlled release fertilizer on loss of nitrogen and phosphorus from farmland. [Method] Experiment was conducted in fields planted with rice and corn around Chao Lake an...[Objective] The aim was to study on effects of controlled release fertilizer on loss of nitrogen and phosphorus from farmland. [Method] Experiment was conducted in fields planted with rice and corn around Chao Lake and effects of compound fertilizer, controlled release fertilizer and controlled release fertilizer （reduced by 20%） on loss of nitrogen and phosphorus through runoff and leaching were analyzed. [Result] Loss of nitrogen and phosphorus mainly occurred in early stage of fertilizing; loss caused by runoff accounted for over 98% and caused by leaching was lower than 2%, indicating that nutrients of rice and corn mainly lost through runoff. As for controlled release fertilizers with 20% reduced, total loss of N and P decreased by 60% and 63% in rice field and reduced by 27.8% and 34% in corn field, respectively, indicating that controlled release fertilizer would maintain nutrients in soils high in later period of plant growth, improve use efficiency of N and P, reduce N and P loss in rice and corn fields in rainy season, and decrease non-point pollution. [Conclusion] The research suggested that controlled release fertilizer would slow down the loss of nutrients in farmlands, providing scientific references and technological support for extension of controlled release fertilizer and reduction of agricultural non-point pollution.展开更多
Phosphorus(P)in surface runoff from purple soil is a critical element of agricultural nonpoint source pollution,leading to eutrophication of surface waters in the Three Gorges Reservoir Area(TGRA)of China.This work ai...Phosphorus(P)in surface runoff from purple soil is a critical element of agricultural nonpoint source pollution,leading to eutrophication of surface waters in the Three Gorges Reservoir Area(TGRA)of China.This work aimed to understand the processes and mechanisms of P losses from bare purple soil.Based on an indoor rainfall simulation experiment,we focused on the processes of surface runoff and P losses via different hydrological pathways.Experimental treatments included three simulated rainfall intensities,four slope gradients,and three fertilizer treatments.P loss from sediment was the main pathway in the purple soil,and bioavailable P was mainly transferred in dissolved P(DP)of runoff water.The P loss loads tend to grow with the increase of the slope until 25°for the maximum load of runoff water and 20°for the maximum load of sediment.Concentrations of DP in the surface runoff after fertilizer application can exceed the estimates of those required for accelerated eutrophication.Sediment P control might be an essential way for reducing P loss in purple soil for the local government and farmers of TGRA.展开更多
This study highlights the influence of freezing-thawing processes on soil erosion in an alpine mine restoration area. Accordingly, a series of simulation experiments were conducted to investigate runoff, sediment, and...This study highlights the influence of freezing-thawing processes on soil erosion in an alpine mine restoration area. Accordingly, a series of simulation experiments were conducted to investigate runoff, sediment, and nutrient losses, and potential influencing factors under freeze-thaw(FT) conditions. Three FT treatments(i.e., 0, 3, and 5 FT cycles), and two soil moisture contents(SMCs;i.e., 10% and 20% SMC on a gravimetric basis) were assessed. The runoff, sediment yield, ammonia nitrogen(AN), nitrate nitrogen(NN), total phosphorus(TP), and dissolved phosphorus(DP) losses from runoff were characterized under different rainfall durations. The fitting results indicated that the runoff rate and sediment rate, AN, NN, TP, and DP concentrations in runoff could be described by exponential functions. FT action increased the total runoff volume and sediment yield by 14.6%–26.0% and 8.8%–35.2%, respectively. The runoff rate and sediment rate increased rapidly with the increment of FT cycles before stabilizing. At 20% SMC, the total runoff volume and sediment yield were significantly higher than those at 10% SMC. The loss curves of AN and NN concentrations varied due to differences in their chemical properties. FT action and high SMC promoted AN and NN losses, whereas the FT cycles had little effect. FT action increased TP and DP losses by 60.2%–220.1% and 48.4%–129.8%, respectively, compared to cases with no FT action;the highest TP and DP losses were recorded at 20% SMC. This study provides a deep understanding of freezing-thawing mechanisms in the soils of alpine mine restoration areas and the influencing factors of these mechanisms on soil erosion, thereby supporting the development of erosion prevention and control measures in alpine mine restoration areas.展开更多
[ Objective] The study aimed to reveal the output characteristics of non-point nitrogen and phosphorus from a typical small watershed in Yimeng mountainous area during a rainstorm. [Method] The dynamic changes of poll...[ Objective] The study aimed to reveal the output characteristics of non-point nitrogen and phosphorus from a typical small watershed in Yimeng mountainous area during a rainstorm. [Method] The dynamic changes of pollutant concentration, precipitation and flow during the rainstorm on August 12, 2010 were monitored at the outlet of Menglianggu watershed. [ Result] During the rainstorm, the generation of runoff was sudden and ephemeral, and the peak of the runoff lagged behind that of rainfall intensity; the concentration of AN and TN increased firstly and then tended to be stable, while NN concentration had no significance change at the beginning of the rainfall, then improved gradually and tended to be stable fi- nally; DOP concentration had no obvious change during the rainstorm, but the concentration of DIP, DP, PP and TP rose firstly and then tended to be stable, and the peak values appeared before the peak of the flow. In addition, the output concentration of TN and TP was far higher than the standard concentration of water eutrophication. [ Conclusion] The study can provide scientific references for the reasonable control of non-point source pollution pollution in Yimeng mountainous area.展开更多
The effects of root oxidization ability and P fertilization on As mobility in soils, and subsequently As uptake, translocation and speciation in rice plants were investigated. Results show that root oxidation signific...The effects of root oxidization ability and P fertilization on As mobility in soils, and subsequently As uptake, translocation and speciation in rice plants were investigated. Results show that root oxidation significantly influences As mobility in rhizoshphere.Genotype TD71 with higher radial oxygen loss(ROL) induces more Fe plaque formation and sequesters more As and P in iron plaque and rhizoshphere soil, leading to the reduction of As accumulation in rice plants. Additionally, P addition mobilizes As in soil solution, and increases As accumulation in rice plants. Arsenic speciation results show that the majority of As species in husks detected is inorganic As, accounting for 82%-93% of the total As, while in grains the majority of As is inorganic As and dimethyl arsenic(DMA), with DMA accounting for 33%-64% of the total As. The fraction of inorganic As decreases while fraction of DMA increases, with increasing As and P concentrations. The study further elucidates the mechanisms involved in effects of ROL on As tolerance and accumulation in rice.展开更多
基金Supported by the Special Fund for Agro-scientific Research in the Public Interest,China(201003014-6)the National Natural Science Foundation of China(31160413)~~
文摘[Objective] Nitrogen and phosphorus losses of surface runoff in various crop rotation systems in the north of Erhai Lake basin were studied with the objective to provide references for risk evaluation of environmental pollution and formulating countermeasures to control the nonpoint source pollution from agriculture.[Method] Water samples collected in four typical crop rotation systems distributed in seven towns（townships） in the north of Erhai Lake basin were investigated,as well as the fertilizer input,to explore the dynamic change of nitrogen and phosphorus content in surface water of farmland and ditch water,and the correlation between fertilizer input and the concentrations of nitrogen and phosphorus in the surface water of farmland and in the ditch water.[Result] The results showed that nitrogen loss in surface water of farmland in different crop rotation systems differed greatly,and the risk of nitrogen loss was 38% lower in broad bean-rice crop rotation than that in garlic-rice crop rotation.The water soluble nitrogen was the primary form of nitrogen loss.The content of water soluble nitrogen was significantly higher in garlic-rice crop rotation than that in the other rotation systems,and the concentrations of nitrogen in the surface water of farmland in different crop rotation systems followed the sequence below：garlic-rice crop rotationryegrass-rice crop rotationbroad bean-rice crop rotationrape-rice crop rotation.The loss of phosphorus in the surface water of farmland was relatively low and phosphorus combined with silt was the primary form for phosphorus loss.There was no significant difference of the loss of various forms of phosphorus in different crop rotation systems.The contents of total nitrogen and total phosphorus in the surface water of farmland were higher than that in ditch water,with increasing rates of total nitrogen and total phosphorus in ditch water of 72% and 82%,respectively.Topdressing was the critical reason for the high concentrations of nitrogen and phosphorus in the surface water,which also caused the increasing load to the ditch water.[Conclusion] Both the nitrogen and phosphorus loss were the highest in garlic-rice crop rotation.Reasonable crop rotation systems should be established based on both the environmental and economic benefits.This study provided references for controlling the nonpoint source pollution of farmland and improving the water quality of Erhai Lake.
基金Project supported by the National Basic Research Program of China(No.2005CB121107)the Innovation Research Group of National Basic Research Program of China(No.2005).
文摘Guanting Reservoir, one of the drinking water supply sources of Beijing, suffers from water eutrophication. It is mainly supplied by Guishui River. Thus, to investigate the reasons of phosphorus （P） loss and improve the P management strategies in Guishui River watershed are important for the safety of drinking water in this region. In this study, a Revised Field P Ranking Scheme （PRS） was developed to reflect the field vulnerability of P loss at the field scale based on the Field PRS. In this new scheme, six factors are included, and each one was assigned a relative weight and a determination method. The affecting factors were classified into transport factors and source factors, and, the standards of environmental quality on surface water and soil erosion classification and degradation of the China were used in this scheme. By the new scheme, thirty-four fields in the Guishui River were categorized as ＂low＂, ＂medium＂ or ＂high＂ potential for P loss into the runoff. The results showed that the P loss risks of orchard and vegetable fields were higher than that of corn and soybean fields. The source factors were the main factors to affect P loss from the study area. In the study area, controlling P input and improving P usage efficiency are critical to decrease P loss. Based on the results, it was suggested that more attention should be paid on the fields of vegetable and orchard since they have extremely high usage rate of P and high soil test of P. Compared with P surplus by field measurements, the Revised Field PRS was more suitable for reflecting the characteristics of fields, and had higher potential capacity to identify critical source areas of P loss than PRS.
基金supported by the International S&T Cooperation Program of Shanghai,China(20390731200)the Major Science and Technology Program for Water Pollution Control and Treatment,China(2017ZX07205)。
文摘A field experiment was carried out to evaluate the effects of drip fertigation combined with plant hedgerows on nitrogen and phosphorus runoff losses in intensive pear orchards in the Tai Lake Basin.Nitrogen and phosphorus runoff over a whole year were measured by using successional runoff water collection devices.The four experimental treatments were conventional fertilization(CK),drip fertigation(DF),conventional fertilization combined with plant hedgerows(C+H),and drip fertigation combined with plant hedgerows(D+H).The results from one year of continuous monitoring showed a significant positive correlation between precipitation and surface runoff discharge.Surface runoff discharge under the treatments without plant hedgerows totaled 15.86%of precipitation,while surface runoff discharge under the treatments with plant hedgerows totaled 12.82%of precipitation.Plant hedgerows reduced the number of runoff events and the amount of surface runoff.Precipitation is the main driving force for the loss of nitrogen and phosphorus in surface runoff,and fertilization is an important factor affecting the losses of nitrogen and phosphorus.In CK,approximately 7.36%of nitrogen and 2.63%of phosphorus from fertilization entered the surface water through runoff.Drip fertigation reduced the accumulation of nitrogen and phosphorus in the surface soil and lowered the runoff loss concentrations of total nitrogen(TN)and total phosphorus(TP).Drip fertigation combined with plant hedgerows significantly reduced the overall TN and TP losses by 45.38 and 36.81%,respectively,in comparison to the CK totals.Drip fertigation increased the vertical migration depth of nitrogen and phosphorus nutrients and reduced the accumulation of nitrogen and phosphorus in the surface soil,which increased the pear yield.The promotion of drip fertigation combined with plant hedgerows will greatly reduce the losses of nitrogen and phosphorus to runoff and maintain the high fruit yields in the intensive orchards of the Tai Lake Basin.
基金funded by the Special Fund for AgroScientific Research in the Public Interest, China (201003014)
文摘Phosphorus（P） losses from agricultural soils contribute to eutrophication of surface waters. This field plot study investigated effects of rainfall regimes and P applications on P loss by surface runoff from rice（Oryza sativa L.） and wheat（Triticum aestivum L.） cropping systems in Lake Taihu region, China. The study was conducted on two types of paddy soils（Hydromorphic at Anzhen site, Wuxi City, and Degleyed at Xinzhuang site, Changshu City, Jiangsu Province） with different P status, and it covered 3 years with low, high and normal rainfall regimes. Four rates of mineral P fertilizer, i.e., no P（control）, 30 kg P ha^（–1） for rice and 20 kg P ha^（–1） for wheat（P_（30＋20））, 75 plus 40（P_（75＋40））, and 150 plus 80（P_（150＋80））, were applied as treatments. Runoff water from individual plots and runoff events was recorded and analyzed for total P and dissolved reactive P concentrations. Losses of total P and dissolved reactive P significantly increased with rainfall depth and P rates（P〈0.0001）. Annual total P losses ranged from 0.36–0.92 kg ha^–1 in control to 1.13–4.67 kg ha^–1 in P150＋80 at Anzhen, and correspondingly from 0.36–0.48 kg h^–1 to 1.26–1.88 kg ha^–1 at Xinzhuang, with 16–49% of total P as dissolved reactive P. In particular, large amounts of P were lost during heavy rainfall events that occurred shortly after P applications at Anzhen. On average of all P treatments, rice growing season constituted 37–86% of annual total P loss at Anzhen and 28–44% of that at Xinzhuang. In both crop seasons, P concentrations peaked in the first runoff events and decreased with time. During rice growing season, runoff P concentrations positively correlated（P〈0.0001） with P concentrations in field ponding water that was intentionally enclosed by construction of field bund. The relative high P loss during wheat growing season at Xinzhuang was due to high soil P status. In conclusion, P should be applied at rates balancing crop removal（20–30 kg P ha^–1 in this study） and at time excluding heavy rains. Moreover, irrigation and drainage water should be appropriately managed to reduce runoff P losses from rice-wheat cropping systems.
基金Supported by NSFC (50839002)Society Development Program of Jiangsu Province (BS2007139)
文摘To achieve the purpose of reducing farm non-point source pollution, we integrated site specific nitrogen management precise irrigation, controlled drainage, and wetland eco-repair system in dike area of Taihu basin. During investigation, it had given prominence for the water and fertilizer coupling effects of precise irrigation and site specific nutrient management, the characteristics of integration on controlled irrigation, controlled drainage and wetland ecosystem non-point source pollution control. Then the water and fertilizer integrated management mode of paddy field was put forward in Taihu basin where the water production efficiency increased to 1.64 kg. m-3, water saved 37.8%, fertilizer use efficiency raised 15,4%, yield raised 10%, and N, P load decreased 26%-72%. The modern agricultural and farmland ecosystems that control and cut down the farm non-point source pollution came into being, which can be a reference by Taihu basin to control its agricultural non-point source pollution and eutrophicated water body.
基金the Fundamental Research Funds for the Central Institutes(No.CAFYBB2019SY014)the National Natural Science Foundation of China,(No.41807151)the Special Fund for Cooperation of Zhejiang Province and the Chinese Academy of Forestry(2021SY12).
文摘Maintaining drinking water security is a global issue,and phosphorus is a limiting factor affecting drinking water quality.Hence,this study took Fushi Reservoir as a test area,and set up field runoff observation plots around the reservoir catchment,which is covered by moso bamboo stands.Through field observation,the vertical variation of phosphorus loss in different stands of moso bamboo was initially studied.The results showed that:(1)For the vertical dimensions(atmospheric rainfall,stemflow,throughfall,surface runoff)from high to low,the loss of total phosphorus(TP)increased,and the pro-portion of dissolved phosphorus increased from 29.29%(atmospheric rainfall)to 62.76%(surface runoff).(2)Different rainfall factors had various impacts on phosphorus loss at the different vertical levels.The accumulation of rainfall had the greatest impact on surface runoff TP loss,with the correlation coefficient reaching 0.994(P<0.01),while surface runoff particulate phosphorus loss was mostly affected by the average rainfall intensity.(3)Modifying the forest structure in water source areas can reduce the loss of TP via stemflow and throughfall,but the effect on surface runoff TP loss is variable.Thus,it is expected that this novel study can serve as a reference for improving the environmental quality of water source areas,and help in reducing phosphorus loss and controlling non-point source pollution.
基金Supported by Major Project of Control and Treatment on Domestic Water Pollution(2012ZX07103003)National 973 Project(2008CB418006)Science and Technology Foundation for Distinguished Young Schlors in Anhui Province(10040606Y30)~~
文摘[Objective] The aim was to study on effects of controlled release fertilizer on loss of nitrogen and phosphorus from farmland. [Method] Experiment was conducted in fields planted with rice and corn around Chao Lake and effects of compound fertilizer, controlled release fertilizer and controlled release fertilizer （reduced by 20%） on loss of nitrogen and phosphorus through runoff and leaching were analyzed. [Result] Loss of nitrogen and phosphorus mainly occurred in early stage of fertilizing; loss caused by runoff accounted for over 98% and caused by leaching was lower than 2%, indicating that nutrients of rice and corn mainly lost through runoff. As for controlled release fertilizers with 20% reduced, total loss of N and P decreased by 60% and 63% in rice field and reduced by 27.8% and 34% in corn field, respectively, indicating that controlled release fertilizer would maintain nutrients in soils high in later period of plant growth, improve use efficiency of N and P, reduce N and P loss in rice and corn fields in rainy season, and decrease non-point pollution. [Conclusion] The research suggested that controlled release fertilizer would slow down the loss of nutrients in farmlands, providing scientific references and technological support for extension of controlled release fertilizer and reduction of agricultural non-point pollution.
基金jointly supported by the National Natural Science Foundation,China(41907124,3210130653,51908233)Program for Innovative Research Team of Excellent Middle-Aged and Young in Higher Education Institutions of Hubei Province(T2021011)+2 种基金Nature Science Foundation of Hubei Province,China(2020CFB465)Educational Commission of Hubei Province,China(D20202503)Open Fund of Research Center for Transition and Development of Resources-exhausted City,China(KF2020Z03)。
文摘Phosphorus(P)in surface runoff from purple soil is a critical element of agricultural nonpoint source pollution,leading to eutrophication of surface waters in the Three Gorges Reservoir Area(TGRA)of China.This work aimed to understand the processes and mechanisms of P losses from bare purple soil.Based on an indoor rainfall simulation experiment,we focused on the processes of surface runoff and P losses via different hydrological pathways.Experimental treatments included three simulated rainfall intensities,four slope gradients,and three fertilizer treatments.P loss from sediment was the main pathway in the purple soil,and bioavailable P was mainly transferred in dissolved P(DP)of runoff water.The P loss loads tend to grow with the increase of the slope until 25°for the maximum load of runoff water and 20°for the maximum load of sediment.Concentrations of DP in the surface runoff after fertilizer application can exceed the estimates of those required for accelerated eutrophication.Sediment P control might be an essential way for reducing P loss in purple soil for the local government and farmers of TGRA.
基金supported by the National Natural Science Foundation of China(U1703244)Bingtuan Science and Technology Program(2021DB019)Science and Technology project of Alar City(2018TF01)。
文摘This study highlights the influence of freezing-thawing processes on soil erosion in an alpine mine restoration area. Accordingly, a series of simulation experiments were conducted to investigate runoff, sediment, and nutrient losses, and potential influencing factors under freeze-thaw(FT) conditions. Three FT treatments(i.e., 0, 3, and 5 FT cycles), and two soil moisture contents(SMCs;i.e., 10% and 20% SMC on a gravimetric basis) were assessed. The runoff, sediment yield, ammonia nitrogen(AN), nitrate nitrogen(NN), total phosphorus(TP), and dissolved phosphorus(DP) losses from runoff were characterized under different rainfall durations. The fitting results indicated that the runoff rate and sediment rate, AN, NN, TP, and DP concentrations in runoff could be described by exponential functions. FT action increased the total runoff volume and sediment yield by 14.6%–26.0% and 8.8%–35.2%, respectively. The runoff rate and sediment rate increased rapidly with the increment of FT cycles before stabilizing. At 20% SMC, the total runoff volume and sediment yield were significantly higher than those at 10% SMC. The loss curves of AN and NN concentrations varied due to differences in their chemical properties. FT action and high SMC promoted AN and NN losses, whereas the FT cycles had little effect. FT action increased TP and DP losses by 60.2%–220.1% and 48.4%–129.8%, respectively, compared to cases with no FT action;the highest TP and DP losses were recorded at 20% SMC. This study provides a deep understanding of freezing-thawing mechanisms in the soils of alpine mine restoration areas and the influencing factors of these mechanisms on soil erosion, thereby supporting the development of erosion prevention and control measures in alpine mine restoration areas.
基金Supported by Science and Technology Innovation Project of Linyi City(201011019)Science and Technology Key Project of Shandong Province(2009GG10006015)Science and Technology Project of Huaihe River Commission,the Ministry of Water Resources (SBJ2010003)
文摘[ Objective] The study aimed to reveal the output characteristics of non-point nitrogen and phosphorus from a typical small watershed in Yimeng mountainous area during a rainstorm. [Method] The dynamic changes of pollutant concentration, precipitation and flow during the rainstorm on August 12, 2010 were monitored at the outlet of Menglianggu watershed. [ Result] During the rainstorm, the generation of runoff was sudden and ephemeral, and the peak of the runoff lagged behind that of rainfall intensity; the concentration of AN and TN increased firstly and then tended to be stable, while NN concentration had no significance change at the beginning of the rainfall, then improved gradually and tended to be stable fi- nally; DOP concentration had no obvious change during the rainstorm, but the concentration of DIP, DP, PP and TP rose firstly and then tended to be stable, and the peak values appeared before the peak of the flow. In addition, the output concentration of TN and TP was far higher than the standard concentration of water eutrophication. [ Conclusion] The study can provide scientific references for the reasonable control of non-point source pollution pollution in Yimeng mountainous area.
基金Project(41201493)supported by the National Natural Science Foundation of ChinaProject(201109056)supported by Special Scientific Research of Environmental Protection for Public Welfare Industry,China
文摘The effects of root oxidization ability and P fertilization on As mobility in soils, and subsequently As uptake, translocation and speciation in rice plants were investigated. Results show that root oxidation significantly influences As mobility in rhizoshphere.Genotype TD71 with higher radial oxygen loss(ROL) induces more Fe plaque formation and sequesters more As and P in iron plaque and rhizoshphere soil, leading to the reduction of As accumulation in rice plants. Additionally, P addition mobilizes As in soil solution, and increases As accumulation in rice plants. Arsenic speciation results show that the majority of As species in husks detected is inorganic As, accounting for 82%-93% of the total As, while in grains the majority of As is inorganic As and dimethyl arsenic(DMA), with DMA accounting for 33%-64% of the total As. The fraction of inorganic As decreases while fraction of DMA increases, with increasing As and P concentrations. The study further elucidates the mechanisms involved in effects of ROL on As tolerance and accumulation in rice.
