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Wang A.-P.,China Coal Research Institute | Li F.-H.,China Agricultural University | Li F.-H.,CAS Institute of Water and Soil Conservation
Pedosphere | Year: 2011

Soil erosion affects soil productivity and environmental quality. A laboratory research experiment under simulated heavy rainfall with tap water was conducted to investigate the effects of anionic polyacrylamide (PAM) application rates (0, 0.5, 1.0, and 2.0 g m -2) and molecular weights (12 and 18 Mg mol -1) on runoff, soil erosion, and soil nutrient loss at a slope of 5°. The results showed the two lower rates of PAM application decreased runoff while the highest rate increased runoff as compared with the control. Sediment concentration and soil mass loss increased significantly with the increasing PAM application rate. Compared with the control, PAM application decreased K +, NH + 4, and NO - 3 concentrations in sediment and K + and NH + 4 concentrations in runoff, but significantly increased the mass losses of K +, NH + 4, and NO - 3 over soil surface except for the NH + 4 at PAM application rate lower than 1.0 g m -2. PAM application decreased the proportion of K + loss with runoff to its total mass loss over soil surface from 60.1% to 16.4%. However, it did not affect the NH + 4 and NO - 3 losses with runoff, and more than 86% of them were lost with runoff. A higher PAM molecular weight resulted in less soil erosion and K + mass loss but had little effect on runoff and NH + 4 and NO - 3 losses. PAM application did not prevent soil erosion and the mass losses of K + and NO - 3 under experimental conditions. © 2011 Soil Science Society of China.


Wang B.,CAS Institute of Water and Soil Conservation | Wang B.,Beijing Normal University | Zhang G.-H.,CAS Institute of Water and Soil Conservation | Zhang G.-H.,Beijing Normal University | And 2 more authors.
Catena | Year: 2014

Land use change has significant effects on soil properties and vegetation cover and thus probably affects soil detachment by overland flow. Few studies were conducted to evaluate the effect of restoration models on the soil detachment process in the Loess Plateau where a Grain for Green Project has been implemented in the past fourteen years. This study was performed to study the effects of vegetation restoration models on soil detachment by overland flow and soil resistance to rill erosion as reflected by rill erodibility and critical shear stress. The undisturbed soil samples were collected from five 37-year-restored lands of abandoned farmland, korshinsk peashrub land (Caragana korshinskill Kom.), black locust land (Robinia pseudoacacia Linn.), Chinese pine land (Pinus tabuliformis Carr.) and mixed forest land of amorpha and Chinese pine. The samples were subjected to flow scouring in a 4.0. m long by 0.35. m wide hydraulic flume under six different shear stresses ranging from 5.60 to 18.15. Pa. The results showed that the measured soil detachment capacities were affected significantly by the restoration models. The mean detachment capacity of cultivated farmland was 23.2 to 55.3 times greater than those of the restored or converted lands. Abandoned farmland showed maximum soil detachment capacity and was 1.02 to 2.29 times greater than the other four restored lands. Soil detachment capacity of the restored lands was significantly influenced by shear stress, cohesion, bulk density, total porosity and root mass density. Detachment capacities were negatively related to cohesion (p<. 0.01) with linear function and root mass density (p<. 0.05) with exponential function, but positively to total porosity (p<. 0.01) with linear function. The rill erodibility would be negatively related to cohesion (p<. 0.01) with power function. Besides, the low rill erodibility in the restored lands always had a low soil detachment capacity, while the critical shear stress in the restored lands varied non-monotonically with detachment capacity. The mixed forest land of amorpha and Chinese pine was considered as the best restoration model for its important role in reducing soil detachment capacity. © 2013 Elsevier B.V.


Dou C.-Y.,China Agricultural University | Li F.-H.,China Agricultural University | Li F.-H.,CAS Institute of Water and Soil Conservation | Wu L.S.,University of California at Riverside
Pedosphere | Year: 2012

The reduction of soil and water losses under furrow irrigation with saline water is important to environmental protection and agricultural production. The objective of this study was to determine the effect of polyacrylamide (PAM) application on soil infiltration and erosion under simulated furrow irrigation with saline water. Polyacrylamide was applied by dissolving it in irrigation water at the rates of 1.5, 7.5, and 15.0 mg L-1 or spreading it as a powder on soil surface at the rates of 0.3, 1.5, 3.0, and 6.0 g m-2, respectively. The electrolyte concentration of tested irrigation water was 10 and 30 mmolc L-1 and its sodium adsorption ratio (SAR) was 0.5, 10.0, and 20.0 (mmolc L-1)0.5. Distilled water was used as a control for irrigation water quality. Results indicated that the electrolyte concentration and SAR generally did not significantly affect soil and water losses after PAM application. Infiltration rate and total infiltration volume decreased with the increase of PAM application rate. Polyacrylamide application in both methods significantly reduced soil erosion, but PAM application rate did not significantly affect it. The solution PAM application was more effective in controlling soil erosion than the powdered PAM application, but the former exerted a greater adverse influence on soil infiltration than the latter. Under the same total amounts, the powdered PAM application resulted in a 38.2%139.6% greater infiltration volume but a soil mass loss of 1.33.4 times greater than the solution PAM application. © 2012 Soil Science Society of China.


LI F.-H.,CAS Institute of Water and Soil Conservation | LI F.-H.,China Agricultural University | ZHANG L.-J.,Changchun Engineering College
Pedosphere | Year: 2010

Irrigation-induced soil erosion seriously affects the sustainability of irrigated agriculture. The effects of irrigation water quality and furrow gradient on runoff and soil loss were studied under simulated furrow irrigation in laboratory using a soil collected from an experimental station of China Agricultural University, North China. The experimental treatments were different combinations of irrigation water salt concentrations of 5, 10, 20, and 30 mmolc L-1, sodium adsorption ratios (SAR) of 0.5, 5.0, and 10.0 (mmolc L-1)0.5, and furrow gradients of 1%, 3%, and 5%, with distilled water for irrigation at 3 furrow gradients as controls. The experimental data indicated that total runoff amount, sediment concentration in runoff, and total soil loss amount generally decreased with increasing salt concentration in irrigation water but increased with its sodicity and furrow gradient. The effects of water quality and furrow gradient on soil loss were greater than those on runoff, and the increase of furrow gradient decreased the influence of water quality on soil loss. When the salt concentration increased from 5 to 30 mmolc L-1 at SAR of 10.0 (mmolc L-1)0.5, total runoff amount, sediment concentration, and total soil loss amount decreased by 3.89%, 52.1%, and 53.92%, and 10.57%, 38.86%, and 42.03% at the furrow gradients of 1% and 5%, respectively. However, they respectively increased by 3.37%, 45.34%, and 55.36%, and 3.86%, 10.77%, and 13.91% when SAR increased from 0.5 to 10.0 (mmolc L-1)0.5 at the salt concentration of 5 mmolc L-1. Irrigation water quality and furrow gradient should be comprehensively considered in the planning and management of furrow irrigation practices to decrease soil loss and improve water utilization efficiency. © 2010 Soil Science Society of China.


Pan C.,Key Laboratory of Water Sediment science | Ma L.,CAS Institute of Water and Soil Conservation | Shangguan Z.,Chinese Academy of SciencesYangling
Water Resources Research | Year: 2016

It is still unclear how slope steepness (S) and revegetation affect resistance (f) to overland flow. A series of experiments on runoff hydraulics was conducted on granular surfaces (bare soil and sandpaper) and grassed surfaces, including grass plots (GP), GP with litter (GL), and GP without leaves (GS) under simulated rainfall and inflow (30


Chen X.P.,China Agricultural University | Chen X.P.,CAS Institute of Water and Soil Conservation | Zhang F.S.,China Agricultural University | Cui Z.L.,China Agricultural University | And 3 more authors.
Soil Science Society of America Journal | Year: 2010

Developing agronomically sound, environmentally appropriate N management strategies are critical for the sustainability of agricultural production. Our objective was to evaluate agronomic performance and potential environmental impacts of in-season N management (INM) against increased or reduced N fertilization on a calcareous alluvial soil for maize (Zea mays L.) in China. Optimal N rates (ONR) were determined for INM by deducting measured soil NO 3-N content in root layers from the N target value during three maize growth periods: from planting to three-leaf stage, three- to 10-leaf stage, and 10-leaf stage to harvest. Other treatments included a 0 N control, below ONR (70% ONR, 50% ONR, or ONR - 30 kg N ha-1), above ONR (130% ONR, 150% ONR, or ONR + 30 kg N ha-1), and farmers' N practice (FNP). Across all 14 sites from 2003 to 2006, when N treatment was less than ONR (average 141 kg N ha-1 ), grain yield was significantly reduced from 8.5 to 7.7 Mgha-1 while maintaining similar residual soil NO3-N content and N losses. When extra N fertilizer was applied, no yield gain was achieved, but N losses were significantly increased from 50 to 81 kg N ha -1 . The FNP treatment had the lowest N recovery (22%) and greatest residual soil NO3-N of 158 kg ha-1 and N loss of 87 kg ha-1. The INM is an extremely practical strategy for effectively utilizing soil N supply, synchronizing N demand and N supply, and addressing site-specific N management needs. © Soil Science Society of America, 5585 Guilford Rd., Madison WI 53711 USA All rights reserved.


Wang Z.,Guizhou University | Wang Z.,CAS Institute of Water and Soil Conservation
Plant Ecology | Year: 2010

Much recent research on ecosystem restoration has focused on specific cases, restoration mechanisms, and techniques in the field. However, there has been less emphasis on the theoretical aspects. Here, species richness is considered as an indicator of ecosystem restoration. The dynamic process of ecosystem restoration is put into a coordinate system consisting of species richness s and time t. The factors affecting ecosystem restoration are introduced into the system to develop dynamic models describing the ecosystem restoration process. We propose that the forces controlling the restoration process include ecosystem restoration force (F1), disturbance force (F2), environmental resistance force (F3), resistance force to disturbance (F4), and the resultant force F, and develop models for their calculation. These forces are functions of time, climate, species immigration rate, disturbance, species richness, and soil nutrient heterogeneity. Disturbance force (F2) and resistance force to disturbance (F4) are positively related to species richness. Our models suggest that the velocity differential ψ of the change in species richness is inversely proportional to species richness and directly proportional to the resultant force F of ecosystem restoration. In the presence of a harmful disturbance, species richness is always lower than maximum species richness sm. The lower the primary richness s0 and immigration rate r in ecosystem restoration, the more obvious the logistic characteristics of the curve of the dynamic process. The dynamic models can be used to predict the restoration of species richness and analyze its dynamic mechanism, and assess the potential for ecosystem restoration. This integrated approach provides a new understanding of ecosystem restoration. © 2009 Springer Science+Business Media B.V.


Du F.,CAS Institute of Soil and Water Conservation | Du F.,CAS Institute of Water and Soil Conservation | Shi H.,CAS Institute of Soil and Water Conservation | Zhang X.,CAS Institute of Soil and Water Conservation | And 2 more authors.
PLoS ONE | Year: 2014

Drought can impact local vegetation dynamics in a long term. In order to predict the possible successional pathway of local community under drought, the responses of some drought resistance indices of six successional seral species in the semiarid Loss Hilly Region of China were illustrated and compared on three levels of soil water deficits along three growing months (7, 8 and 9). The results showed that: 1) the six species had significant differences in SOD, POD activities and MDA content. The rank correlations between SOD, POD activities and the successional niche positions of the six species were positive, and the correlation between MDA content and the niche positions was negative; 2) activities of SOD, CAT and POD, and content of proline and MDA had significant differences among the three months; 3) there existed significant interactions of SOD, CAT, POD activities and MDA content between months and species. With an exception, no interaction of proline was found. Proline in leaves had a general decline in reproductive month; 4) SOD, CAT, POD activities and proline content had negative correlations with MDA content. Among which, the correlation between SOD activity and MDA content was significant. The results implied that, in arid or semiarid region, the species at later successional stage tend to have strong drought resistance than those at early stage. Anti-drought indices can partially interpret the pathway of community succession in the drought impacted area. SOD activity is more distinct and important on the scope of protecting membrane damage through the scavenging of ROS on exposure to drought. © 2014 Du et al.


Liang B.,Northwest University, China | Yang X.,Northwest University, China | He X.,Edith Cowan University | He X.,University of Western Australia | And 2 more authors.
Biology and Fertility of Soils | Year: 2011

As labile organic pools, soluble organic matter and soil microbial biomass are sensitive to changes in soil management and therefore good indicators of soil quality. Effects of a 17-year long-term fertilization on soil microbial biomass C (SMBC) and N (SMBN), soluble organic C, and soluble organic N during the maize growing season were evaluated in a loess soil (Eum-Orthic Anthrosol) in northwest China. The fertilization treatments included no fertilizer (CK), inorganic N, P, and K fertilizer (NPK), cattle manure plus NPK fertilizer (MNPK), and straw plus NPK fertilizer (SNPK). Our results showed that C storage in the 0-20 cm soil layer was 28% to 81% higher in the fertilized treatments compared to the unfertilized treatment. In the 0-10 cm soil layer, SMBC and SMBN in the three fertilized treatments were higher than in the unfertilized treatment on all sampling dates, while microbial biomass C and N in the 0-10 cm soil layers were the highest at grain filling. In the same soil layer, soil-soluble organic C generally decreased in the order MNPK> SNPK> NPK> CK, while soluble organic N was the highest in the MNPK followed by the SNPK treatment. There was no significant difference in soluble organic N in the NPK and CK treatments throughout most of the maize growing season. Changes in soluble organic N occurred along the growing season and were more significant than those for soluble organic C. Soluble organic N was the highest at grain filling and the lowest at harvest. Overall, our results indicated that microbial biomass and soluble organic N in the surface soil were generally the highest at grain filling when maize growth was most vigorous. Significant positive relationships were found between soluble organic C and SMBC and between soluble organic N and SMBN. © 2010 Springer-Verlag.


Zhang C.-B.,CAS Institute of Water and Soil Conservation | Chen L.-H.,CAS Institute of Water and Soil Conservation | Liu Y.-P.,CAS Institute of Water and Soil Conservation | Ji X.-D.,CAS Institute of Water and Soil Conservation | Liu X.-P.,Chinese Academy of Sciences
Ecological Engineering | Year: 2010

In order to evaluate influences of roots on soil shear strength, a triaxial compression test was carried out to study the shear strength of plain soil samples and composites comprised of roots of Robinia pseucdoacacia and soil from the Loess Plateau in Northwest China. Roots were distributed in soil in three forms: vertical, horizontal, and vertical-horizontal (cross). All samples were tested under two different soil water contents. Test results showed that roots have more impacts on the soil cohesion than the friction angle. The presence of roots in soil substantially increased the soil shear strength. Among three root distribution forms, the reinforcing effect of vertical-horizontal (cross) root distribution was the most effective. Increase in soil water content directly induced a decline in soil cohesion of all test samples and resulted in a decrease in shear strength for both plain soil samples and soil-root composites. It was concluded that the triaxial compression test can be effectively used to study influences of roots on soil shear strength. © 2009 Elsevier B.V. All rights reserved.

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