Phosphorus(P)leaching in alkaline soils,exacerbated by excessive fertilizer application,represents a significant pathway for P loss.While soil pore structure and texture critically regulate P transport,mechanisms gove...Phosphorus(P)leaching in alkaline soils,exacerbated by excessive fertilizer application,represents a significant pathway for P loss.While soil pore structure and texture critically regulate P transport,mechanisms governing P loss in texturally diverse alkaline soils remain unclear.This study investigated P leaching dynamics and transport parameters across four alkaline soil textures(silty clay,clay loam,loam,sandy loam)using a one-dimensional convective-diffusion equation(CDE)based on column experiments.Results indicated that phosphorus leaching kinetics were predominantly governed by diffusion transport,evidenced by low Peclet numbers(P_(e))(ranged from 0.02 to 0.31)across varying textures and initial P concentrations(C_(0)).Comparative analysis of transport parameters revealed significant textural effects on dispersion coefficient(D),retardation factor(R),pore water velocity(V),P_(e),and diffusion coefficient(λ)(F>523.42,p<0.001).Among these,only D,P_(e) andλexhibited substantial differences in response to variations in C_(0)(F>89.47,p<0.001).Saturated hydraulic conductivity(K_(s))(R^(2)=62.9%,p<0.01)and total pore area(A)(R^(2)=12.4%,p<0.01)emerged as primary regulators of P leaching.Enhanced clay content increased total pore area while reducing average pore diameter,concurrently decreasing pore water velocity and saturated infiltration rates.These textural modifications amplified diffusive P transport within soil matrices.The findings provide mechanistic insights into texturedependent P mobility in alkaline environments,informing targeted strategies for agricultural phosphorus management.展开更多
Nitrogen（N） loss from fertilization in agricultural fields has an unavoidable negative impact on the environment and a better understanding of the major pathways can assist in developing the best management practice...Nitrogen（N） loss from fertilization in agricultural fields has an unavoidable negative impact on the environment and a better understanding of the major pathways can assist in developing the best management practices. The aim of this study was to evaluate the fate of N fertilizers applied to acidic red soil（Ferralic Cambisol） after 19 years of mineral（synthetic） and manure fertilizer treatments under a cropping system with wheat-maize rotations. Five field treatments were examined： control（CK）, chemical nitrogen and potash fertilizer（NK）, chemical nitrogen and phosphorus fertilizer（NP）, chemical nitrogen, phosphorus and potash fertilizer（NPK） and the NPK with manure（NPKM, 70% N from manure）. Based on the soil total N storage change in 0–100 cm depth, ammonia（NH_3） volatilization, nitrous oxide（N_2O） emission, N plant uptake, and the potential N leaching loss were estimated using a mass balance approach. In contrast to the NPKM, all mineral fertilizer treatments（NK, NP and NPK） showed increased nitrate（NO_3~–） concentration with increasing soil depth, indicating higher leaching potential. However, total NH_3 volatilization loss was much higher in the NPKM（19.7%） than other mineral fertilizer treatments（≤4.2%）. The N_2O emissions were generally low（0.2–0.9%, the highest from the NPKM）. Total gaseous loss accounted for 1.7, 3.3, 5.1, and 21.9% for NK, NP, NPK, and NPKM treatments, respectively. Estimated N leaching loss from the NPKM was only about 5% of the losses from mineral fertilizer treatments. All data demonstrated that manure incorporation improved soil productivity, increased yield, and reduced potential leaching, but with significantly higher NH_3 volatilization, which could be reduced by improving the application method. This study confirms that manure incorporationis an essential strategy in N fertilization management in upland red soil cropping system.展开更多
The combined application of mineral fertilizer and biochar significantly improves the passivation of heavy metal-contaminated soil,surpassing the effects of individual application.This study has reinforced the validat...The combined application of mineral fertilizer and biochar significantly improves the passivation of heavy metal-contaminated soil,surpassing the effects of individual application.This study has reinforced the validation of their passivation competence as soil remediation agents by examining the multifaceted role of potassium-silicon-calcium mineral fertilizer combined with rice husk-based biochar generated at different pyrolysis temperatures.The soil leaching column experiment,conducted based on the adsorption experiments,has facilitated our scrutiny of the passivation impacts of cadmium(Cd)and lead(Pb)when introducing different proportions of mineral fertilizers and biochar into the soil.These results indicate that biochar’s adsorption efficiency for Cd and Pb is significantly improved at escalated pyrolytic temperature conditions in a single solution.The biochar generated at 700℃(C700)renders adsorption effectiveness of approximately 84.24%for Cd and 99.74%for Pb.Biochar conspicuously registers superior adsorption efficiency towards Pb relative to Cd.The mineral fertilizer,which achieves an adsorption efficiency of 97.76%for Cd,is identified as the main adsorbent for Cd,although its competence is slightly lower compared to C700 for Pb adsorption.Within a complex solution,biochar and mineral fertilizer show reduced Cd and Pb adsorption levels compared to single solutions.There is a keen competition for adsorption surfaces witnessed between Cd and Pb,with Pb’s distribution coefficient(Kd)notably outpacing that of Cd.The isothermal adsorption analyses depict that the mineral fertilizer follows the Langmuir model for Cd adsorption,while C700 conveys the Freundlich model for Pb adsorption.The soil leaching column experiment’s results signify that the composite passivation agents significantly outperform the individual passivation agents in efficiency.The combined application of biochar and mineral fertilizer minimizes the cumulative leaching of Cd and Pb,with the optimal soil remedy proportion for heavy metal contamination being 7∶3.In practical application,mindful consideration should be accorded to the deployment ratios of different passivation agents.展开更多
Experiment was conducted for five successiveyears under large undisturbed monolith lysime-ters(2m×2m in square,l m in depth).Thesoil was silty clay loam texture and had a con-tent of total N 1.55 g/kg.The soil wa...Experiment was conducted for five successiveyears under large undisturbed monolith lysime-ters(2m×2m in square,l m in depth).Thesoil was silty clay loam texture and had a con-tent of total N 1.55 g/kg.The soil was flood-ed with penetration rate controlled at approxi-mate 3 mm per day in duration of double-riceseason and laid fallow and natural in winterand spring.Results showed that nitrate was the mainform of nitrogen in percolates.The change of展开更多
Plant roots have potential impacts on soil mineral weathering and leaching.Our objective is to understand the physical mechanisms of plant roots affecting weathering andleaching of loess soil.Root densities were measu...Plant roots have potential impacts on soil mineral weathering and leaching.Our objective is to understand the physical mechanisms of plant roots affecting weathering andleaching of loess soil.Root densities were measured through the method of a large-size dug profile,and transport fluxes of soil elements were determined using an undisturbed monolith soilinfiltration device on the hilly and gully regions of the Chinese Loess Plateau.The results showthat the improvement effects of soil environment by plant roots are mainly controlled by the densityand weight of the fibrous roots with the diameters less than 1 mm.Plant roots have the strongereffects on soil physical properties than chemical properties.The principal components analysis(PCA)indicates that soil physical properties by plant roots account for 56.7%of variations in soilenvironment whereas soil chemical properties and pH contribute about 24.2%of the soil variations.The roles of plant roots in controlling soil weathering and leaching increased in the followingorder:infiltration enhancement】increase of bio-active substance】stabilization of soilstructure.The effects of plant roots on soil mineral weathering and leaching can be quantifiedusing the multiple regression models with the high prediction accuracies developed in this study.展开更多
基金supported by the National Natural Science Foundation of China(Nos.42077067,42277329)the Projects of Talents Recruitment of GDUPT(No.XJ2005000301)。
文摘Phosphorus(P)leaching in alkaline soils,exacerbated by excessive fertilizer application,represents a significant pathway for P loss.While soil pore structure and texture critically regulate P transport,mechanisms governing P loss in texturally diverse alkaline soils remain unclear.This study investigated P leaching dynamics and transport parameters across four alkaline soil textures(silty clay,clay loam,loam,sandy loam)using a one-dimensional convective-diffusion equation(CDE)based on column experiments.Results indicated that phosphorus leaching kinetics were predominantly governed by diffusion transport,evidenced by low Peclet numbers(P_(e))(ranged from 0.02 to 0.31)across varying textures and initial P concentrations(C_(0)).Comparative analysis of transport parameters revealed significant textural effects on dispersion coefficient(D),retardation factor(R),pore water velocity(V),P_(e),and diffusion coefficient(λ)(F>523.42,p<0.001).Among these,only D,P_(e) andλexhibited substantial differences in response to variations in C_(0)(F>89.47,p<0.001).Saturated hydraulic conductivity(K_(s))(R^(2)=62.9%,p<0.01)and total pore area(A)(R^(2)=12.4%,p<0.01)emerged as primary regulators of P leaching.Enhanced clay content increased total pore area while reducing average pore diameter,concurrently decreasing pore water velocity and saturated infiltration rates.These textural modifications amplified diffusive P transport within soil matrices.The findings provide mechanistic insights into texturedependent P mobility in alkaline environments,informing targeted strategies for agricultural phosphorus management.
基金supported by the National Key Research and Development Program of China(2016YFD0200301)the open fund of Key Laboratory of Non-point Source Pollution Control,Ministry of Agriculture,China(20130104)the Key Technologies R&D Program of China during the 12th Five-year Plan period(2012BAD14B04)
文摘Nitrogen（N） loss from fertilization in agricultural fields has an unavoidable negative impact on the environment and a better understanding of the major pathways can assist in developing the best management practices. The aim of this study was to evaluate the fate of N fertilizers applied to acidic red soil（Ferralic Cambisol） after 19 years of mineral（synthetic） and manure fertilizer treatments under a cropping system with wheat-maize rotations. Five field treatments were examined： control（CK）, chemical nitrogen and potash fertilizer（NK）, chemical nitrogen and phosphorus fertilizer（NP）, chemical nitrogen, phosphorus and potash fertilizer（NPK） and the NPK with manure（NPKM, 70% N from manure）. Based on the soil total N storage change in 0–100 cm depth, ammonia（NH_3） volatilization, nitrous oxide（N_2O） emission, N plant uptake, and the potential N leaching loss were estimated using a mass balance approach. In contrast to the NPKM, all mineral fertilizer treatments（NK, NP and NPK） showed increased nitrate（NO_3~–） concentration with increasing soil depth, indicating higher leaching potential. However, total NH_3 volatilization loss was much higher in the NPKM（19.7%） than other mineral fertilizer treatments（≤4.2%）. The N_2O emissions were generally low（0.2–0.9%, the highest from the NPKM）. Total gaseous loss accounted for 1.7, 3.3, 5.1, and 21.9% for NK, NP, NPK, and NPKM treatments, respectively. Estimated N leaching loss from the NPKM was only about 5% of the losses from mineral fertilizer treatments. All data demonstrated that manure incorporation improved soil productivity, increased yield, and reduced potential leaching, but with significantly higher NH_3 volatilization, which could be reduced by improving the application method. This study confirms that manure incorporationis an essential strategy in N fertilization management in upland red soil cropping system.
基金supported by the National Natural Science Foundation of Sichuan Province(22NSFSC0191,22NSFSC3990)。
文摘The combined application of mineral fertilizer and biochar significantly improves the passivation of heavy metal-contaminated soil,surpassing the effects of individual application.This study has reinforced the validation of their passivation competence as soil remediation agents by examining the multifaceted role of potassium-silicon-calcium mineral fertilizer combined with rice husk-based biochar generated at different pyrolysis temperatures.The soil leaching column experiment,conducted based on the adsorption experiments,has facilitated our scrutiny of the passivation impacts of cadmium(Cd)and lead(Pb)when introducing different proportions of mineral fertilizers and biochar into the soil.These results indicate that biochar’s adsorption efficiency for Cd and Pb is significantly improved at escalated pyrolytic temperature conditions in a single solution.The biochar generated at 700℃(C700)renders adsorption effectiveness of approximately 84.24%for Cd and 99.74%for Pb.Biochar conspicuously registers superior adsorption efficiency towards Pb relative to Cd.The mineral fertilizer,which achieves an adsorption efficiency of 97.76%for Cd,is identified as the main adsorbent for Cd,although its competence is slightly lower compared to C700 for Pb adsorption.Within a complex solution,biochar and mineral fertilizer show reduced Cd and Pb adsorption levels compared to single solutions.There is a keen competition for adsorption surfaces witnessed between Cd and Pb,with Pb’s distribution coefficient(Kd)notably outpacing that of Cd.The isothermal adsorption analyses depict that the mineral fertilizer follows the Langmuir model for Cd adsorption,while C700 conveys the Freundlich model for Pb adsorption.The soil leaching column experiment’s results signify that the composite passivation agents significantly outperform the individual passivation agents in efficiency.The combined application of biochar and mineral fertilizer minimizes the cumulative leaching of Cd and Pb,with the optimal soil remedy proportion for heavy metal contamination being 7∶3.In practical application,mindful consideration should be accorded to the deployment ratios of different passivation agents.
文摘Experiment was conducted for five successiveyears under large undisturbed monolith lysime-ters(2m×2m in square,l m in depth).Thesoil was silty clay loam texture and had a con-tent of total N 1.55 g/kg.The soil was flood-ed with penetration rate controlled at approxi-mate 3 mm per day in duration of double-riceseason and laid fallow and natural in winterand spring.Results showed that nitrate was the mainform of nitrogen in percolates.The change of
基金This work was supported by the National Natural Science Foundation of China(Grant Nos.90202005 and 40071054)China Postdoctoral Science Foundation.
文摘Plant roots have potential impacts on soil mineral weathering and leaching.Our objective is to understand the physical mechanisms of plant roots affecting weathering andleaching of loess soil.Root densities were measured through the method of a large-size dug profile,and transport fluxes of soil elements were determined using an undisturbed monolith soilinfiltration device on the hilly and gully regions of the Chinese Loess Plateau.The results showthat the improvement effects of soil environment by plant roots are mainly controlled by the densityand weight of the fibrous roots with the diameters less than 1 mm.Plant roots have the strongereffects on soil physical properties than chemical properties.The principal components analysis(PCA)indicates that soil physical properties by plant roots account for 56.7%of variations in soilenvironment whereas soil chemical properties and pH contribute about 24.2%of the soil variations.The roles of plant roots in controlling soil weathering and leaching increased in the followingorder:infiltration enhancement】increase of bio-active substance】stabilization of soilstructure.The effects of plant roots on soil mineral weathering and leaching can be quantifiedusing the multiple regression models with the high prediction accuracies developed in this study.
