Low quality water has been widely used for irrigation all over the world due to water shortage.However,the use of low quality water may cause accumulation of salt in root-zone soils,resulting in poor nitrogen utilizat...Low quality water has been widely used for irrigation all over the world due to water shortage.However,the use of low quality water may cause accumulation of salt in root-zone soils,resulting in poor nitrogen utilization by crops.The objective of the present study was to investigate the effects of sodium chloride(NaCl)on mineralization and nitrification of soils in the North China Plain(NCP).The experiments were conducted with laboratory incubators at 30℃.Five levels of NaCl-salt concentrations 0%,2%,3%,5%and 8%in the added solutions were used in the soil samples collected from NCP.The mineralization at NaCl-salt concentration lower than 3%was not significantly different from that of the control,whereas,significant inhibition of mineralization was found in the treatments with NaCl-salt concentration higher than 3%.The inhibition of mineralization was attributed to the retardation of nitrification in relatively high salt content because ammonification was not depressed by the added NaCl salt.The gas losses and nitrification were found decreasing with the increase in salinity.It was also found that the nitrification was more sensitive to salinity than the mineralization.Nitrification of soil samples was inhibited by 44.72%,57.87%,and 83.64%compared with the control after 38 days of incubation at NaCl-salt concentrations of 3%,5%and 8%,respectively.The time dependence of both the mineralization and nitrification can be fitted into a first-order kinetic model.The rate constant of mineralization and nitrification decreased exponentially with the salt content in the soils.The results of the present research may provide some scientific implications for the use of saline water or treated sewage water in the farming regions of the NCP.展开更多
In this study, soil column was used to study the new nitrification inhibitor 3,4-dimethylpyrazole phosphate （DMPP） on nitrate （NO3^-- N） and potassium （K） leaching in the sandy loam soil and clay loam soil. The ...In this study, soil column was used to study the new nitrification inhibitor 3,4-dimethylpyrazole phosphate （DMPP） on nitrate （NO3^-- N） and potassium （K） leaching in the sandy loam soil and clay loam soil. The results showed that DMPP with ammonium sulphate nitrate （ASN） （（NH4）2SO4 and NHaNO3） or urea could reduce NO3^--N leaching significantly, whereas ammonium （NH4^＋-N） leaching increased slightly. In case of total N （NO3^--N＋NH4^＋-N）, losses by leaching during the experimental period （40 d） were 37.93 mg （urea）, 31.61 mg （urea＋DMPP）, 108.10 mg （ASN）, 60.70 mg （ASN＋DMPP） in the sandy loam soil, and 30.54 mg （urea）, 21.05 mg （urea＋DMPP）, 37.86 mg （ASN）, 31.09 mg （ASN＋DMPP） in the clay loam soil, respectively. DMPP-amended soil led to the maintenance of relatively high levels of NH4^＋ -N and low levels of NO3^--N in soil, and nitrification was slower. DMPP supplementation also resulted in less potassium leached, but the difference was not significant except the treatment of ASN and ASN＋DMPP in the sandy loam soil. Above results indicate that DMPP is a good nitrification inhibitor, the efficiency of DMPP seems better in the sandy loam soil than in the clay loam soil and lasts longer.展开更多
Lead (Pb) was detected in potential urban garden soil in Claremont Cali-fornia and was absorbed by radish cultivars and giant red mustard in a bioassay of the contaminated soil. Radish cultivars grown in two soils wit...Lead (Pb) was detected in potential urban garden soil in Claremont Cali-fornia and was absorbed by radish cultivars and giant red mustard in a bioassay of the contaminated soil. Radish cultivars grown in two soils with two lead salts developed the same lead tissue concentrations. In a subsequent study, Cultivar “Rudolf” accumulated less lead nitrate than cultivars “French Breakfast” and “White Beauty”. Cultivar “Rudolf” grew the least biomass likely accounting for its reduced Pb accumulation. All radish cultivars accumulated more lead when grown in clay vs. sand soil and radish Pb accumulation increased when the concentration of lead was increased in either soil type. The solubility of the lead ion used was not associated with Pb uptake by radish.展开更多
The present study is about to find out different attributes of soil as well as geomorphology. It is very much relevant to the study of land use land cover (LULC). Garpanchkot hill is situated in Purulia district of We...The present study is about to find out different attributes of soil as well as geomorphology. It is very much relevant to the study of land use land cover (LULC). Garpanchkot hill is situated in Purulia district of West Bengal. There are two geomorphological and seven pedological parameters that have been selected for the study. Shuttle radar topographic mission (SRTM) and advanced land observing satellite (ALOS) data are analyzed by remote sensing software to find out the geomorphological character of the area. There are twenty soil samples that have been taken from top of the hill to foothill pediment area with the change of elevation and slope for laboratory analysis. Different statistical techniques are used for representation. Foot hill area of the Garpanchkot hill can be determined by less than 150 m elevation and 5o slope. Elevation and slope of rest of the hill area (greater than 150 m and 5o) are fully dominated by forest and scattered vegetation. Elevated area (greater than 205 m) with less slope (10o - 15o) is associated with dense forest. Escarpment area is associated with grass land and scattered vegetation. Foothill area is bearing the signature of scattered vegetation, bare soil ground and agriculture. The richness of clay minerals plays an important role in the foothill pediment area for development of agriculture. Sandy loam is dominating soil texture in the rest of the hill area. Percentage of organic matter (1.8%), status of salinity (6.65 - 7.72) and alkalinity (up to 138.6 μs/cm) remain high in the high elevated area due to forest cover. The area is very dry, only fed by the rainfall during monsoon season. Artificial reservoir feeds the foothill agriculture system. Rice, wheat, maize, sugarcane, pulses chili and vegetables are the main crops of this area.展开更多
为获取南方地区黏弹性壤土颗粒离散元接触模型的本征物理参数和接触力学参数,建立其用于离散元仿真的接触模型。以试验测定的堆积角为40.95°的壤土为研究对象,选取Hertz–Mindlin with JKR接触模型,通过实测试验获取壤土的本征物...为获取南方地区黏弹性壤土颗粒离散元接触模型的本征物理参数和接触力学参数,建立其用于离散元仿真的接触模型。以试验测定的堆积角为40.95°的壤土为研究对象,选取Hertz–Mindlin with JKR接触模型,通过实测试验获取壤土的本征物理参数值;借助GEMM数据库推荐的土壤接触力学参数初选范围,通过最陡爬坡试验得到接触力学参数值的最优值区间。利用Design–Expert软件对最优值区间的接触力学参数进行4因素3水平二次正交旋转组合试验,获取堆积角回归模型,以实测土壤堆积角40.95°为目标,对回归模型进行接触力学参数寻优,得到接触力学参数的最优组合为:JKR表面能13.05 J/m2,恢复系数0.5,动摩擦因数0.15,静摩擦因数1.06,该最优组合参数仿真堆积角均值为41.07°,与实测堆积角误差为0.3%。展开更多
基金The project was supported by the National Natural Science Foundation of China(grant numbers:50639040,50779067)the Chinese State High-Tech“863”Program(grant number:2006AA100207)the Program for New Century Excellent Talents in University(grant number:NCET-05-0125).
文摘Low quality water has been widely used for irrigation all over the world due to water shortage.However,the use of low quality water may cause accumulation of salt in root-zone soils,resulting in poor nitrogen utilization by crops.The objective of the present study was to investigate the effects of sodium chloride(NaCl)on mineralization and nitrification of soils in the North China Plain(NCP).The experiments were conducted with laboratory incubators at 30℃.Five levels of NaCl-salt concentrations 0%,2%,3%,5%and 8%in the added solutions were used in the soil samples collected from NCP.The mineralization at NaCl-salt concentration lower than 3%was not significantly different from that of the control,whereas,significant inhibition of mineralization was found in the treatments with NaCl-salt concentration higher than 3%.The inhibition of mineralization was attributed to the retardation of nitrification in relatively high salt content because ammonification was not depressed by the added NaCl salt.The gas losses and nitrification were found decreasing with the increase in salinity.It was also found that the nitrification was more sensitive to salinity than the mineralization.Nitrification of soil samples was inhibited by 44.72%,57.87%,and 83.64%compared with the control after 38 days of incubation at NaCl-salt concentrations of 3%,5%and 8%,respectively.The time dependence of both the mineralization and nitrification can be fitted into a first-order kinetic model.The rate constant of mineralization and nitrification decreased exponentially with the salt content in the soils.The results of the present research may provide some scientific implications for the use of saline water or treated sewage water in the farming regions of the NCP.
基金Project supported by the National Natural Science Foundation of China(No. 30571082)the Science and Technology Committee of ZhejiangProvince (No. 021102084)the Agriculture Department of ZhejiangProvince (No. SN 200404) and BASF Company of Germany.
文摘In this study, soil column was used to study the new nitrification inhibitor 3,4-dimethylpyrazole phosphate （DMPP） on nitrate （NO3^-- N） and potassium （K） leaching in the sandy loam soil and clay loam soil. The results showed that DMPP with ammonium sulphate nitrate （ASN） （（NH4）2SO4 and NHaNO3） or urea could reduce NO3^--N leaching significantly, whereas ammonium （NH4^＋-N） leaching increased slightly. In case of total N （NO3^--N＋NH4^＋-N）, losses by leaching during the experimental period （40 d） were 37.93 mg （urea）, 31.61 mg （urea＋DMPP）, 108.10 mg （ASN）, 60.70 mg （ASN＋DMPP） in the sandy loam soil, and 30.54 mg （urea）, 21.05 mg （urea＋DMPP）, 37.86 mg （ASN）, 31.09 mg （ASN＋DMPP） in the clay loam soil, respectively. DMPP-amended soil led to the maintenance of relatively high levels of NH4^＋ -N and low levels of NO3^--N in soil, and nitrification was slower. DMPP supplementation also resulted in less potassium leached, but the difference was not significant except the treatment of ASN and ASN＋DMPP in the sandy loam soil. Above results indicate that DMPP is a good nitrification inhibitor, the efficiency of DMPP seems better in the sandy loam soil than in the clay loam soil and lasts longer.
文摘Lead (Pb) was detected in potential urban garden soil in Claremont Cali-fornia and was absorbed by radish cultivars and giant red mustard in a bioassay of the contaminated soil. Radish cultivars grown in two soils with two lead salts developed the same lead tissue concentrations. In a subsequent study, Cultivar “Rudolf” accumulated less lead nitrate than cultivars “French Breakfast” and “White Beauty”. Cultivar “Rudolf” grew the least biomass likely accounting for its reduced Pb accumulation. All radish cultivars accumulated more lead when grown in clay vs. sand soil and radish Pb accumulation increased when the concentration of lead was increased in either soil type. The solubility of the lead ion used was not associated with Pb uptake by radish.
文摘The present study is about to find out different attributes of soil as well as geomorphology. It is very much relevant to the study of land use land cover (LULC). Garpanchkot hill is situated in Purulia district of West Bengal. There are two geomorphological and seven pedological parameters that have been selected for the study. Shuttle radar topographic mission (SRTM) and advanced land observing satellite (ALOS) data are analyzed by remote sensing software to find out the geomorphological character of the area. There are twenty soil samples that have been taken from top of the hill to foothill pediment area with the change of elevation and slope for laboratory analysis. Different statistical techniques are used for representation. Foot hill area of the Garpanchkot hill can be determined by less than 150 m elevation and 5o slope. Elevation and slope of rest of the hill area (greater than 150 m and 5o) are fully dominated by forest and scattered vegetation. Elevated area (greater than 205 m) with less slope (10o - 15o) is associated with dense forest. Escarpment area is associated with grass land and scattered vegetation. Foothill area is bearing the signature of scattered vegetation, bare soil ground and agriculture. The richness of clay minerals plays an important role in the foothill pediment area for development of agriculture. Sandy loam is dominating soil texture in the rest of the hill area. Percentage of organic matter (1.8%), status of salinity (6.65 - 7.72) and alkalinity (up to 138.6 μs/cm) remain high in the high elevated area due to forest cover. The area is very dry, only fed by the rainfall during monsoon season. Artificial reservoir feeds the foothill agriculture system. Rice, wheat, maize, sugarcane, pulses chili and vegetables are the main crops of this area.
文摘为获取南方地区黏弹性壤土颗粒离散元接触模型的本征物理参数和接触力学参数,建立其用于离散元仿真的接触模型。以试验测定的堆积角为40.95°的壤土为研究对象,选取Hertz–Mindlin with JKR接触模型,通过实测试验获取壤土的本征物理参数值;借助GEMM数据库推荐的土壤接触力学参数初选范围,通过最陡爬坡试验得到接触力学参数值的最优值区间。利用Design–Expert软件对最优值区间的接触力学参数进行4因素3水平二次正交旋转组合试验,获取堆积角回归模型,以实测土壤堆积角40.95°为目标,对回归模型进行接触力学参数寻优,得到接触力学参数的最优组合为:JKR表面能13.05 J/m2,恢复系数0.5,动摩擦因数0.15,静摩擦因数1.06,该最优组合参数仿真堆积角均值为41.07°,与实测堆积角误差为0.3%。
