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Copyright of Journal of Agro-Environment Science is the property of Journal of Agro-Environment Science Editorial Board and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Copyright of Journal of Soil & Water Conservation (1009-2242) is the property of Institute of Soil & Water Conservation and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Copyright of Journal of Soil & Water Conservation (1009-2242) is the property of Institute of Soil & Water Conservation and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Copyright of Mountain Research (10082786) is the property of Mountain Research Editorial Office and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Mechanical stability of soil structure determined the scour resistance, erodibility, collapsibility, slope stability, and foundation stability of the soil, even the large-scale agricultural instruments, as well as irrigation and water conservancy projects. Alternatively, rheology has widely been one part of soil physical characterization under deformation. The rheological parameters can be utilized to clarify the highly complex soil process, including the most significant soil aggregation factors, such as soil bulk density and water content. In this study, the widely distributed Lou soil and loessal soil on the Loess Plateau were selected as the research objects. An amplitude scanning test was selected to simulate the oscillation load process. An investigation was made on the effect of soil bulk density and water content on the mechanical stability of soil structure under the oscillation load. The results show that: 1) The soil density increased the contact point between soil particles, leading to the increasing cohesion and friction between particles. The shear strength parameters were all increased, including the shear stress at the linear viscoelastic region, the shear stress at yield point, the maximum shear stress, and the storage modulus at the yield point, as the increase of soil bulk density, indicating the increase in the stability of soil structure. In terms of viscoelastic parameters, the shear strain at the linear viscoelasticity region and the maximum shear stress decreased, whereas, the shear strain at yield points and integral zone increased first and then decreased, with the increase of soil bulk density. Soil particles were under the most stable way of organization and combination (1.3 g/cm3 ). Shear strength parameters with the change of soil bulk density were more sensitive than viscoelastic parameters. 2) As the increase of soil water content, the shear strength parameters presented the decreasing trends, including the shear stress at the linear viscoelastic region, the shear stress at yield point, the maximum shear stress, and the storage modulus at the yield point, indicating the decreased stability of soil structure. In viscoelastic parameters, the shear strain at the linear viscoelasticity region increased with the increase of water content, but the shear strain at yield point and integral zone decreased. It indicated that the cohesion and friction between soil particles decreased, with the increase of soil water content. The higher water content of soil particles decreased the relative sliding resistance between particles, leading to the deterioration of soil structural stability. 3) The elasticity and shear strength of Lou soil was higher than that of Loessal soil. This was mainly because Lou soil contained a higher content of clay, organic matter, cation exchange capacity, and specific surface area than those of Loessal soil, indicating the improved cementation strength between soil particles. Consequently, the rheological parameters from the amplitude scanning test in the rheometer can be used to quantitatively characterize the mechanical stability of soil structure, providing for rich evaluation parameters to further understand the micromechanical properties of soil. The finding can provide a shred of strong scientific evidence for agricultural water and soil engineering design, as well as the prevention and control of landslide and geological disasters in the Loess Plateau. [ABSTRACT FROM AUTHOR]

Copyright of Chinese Journal of Applied Ecology / Yingyong Shengtai Xuebao is the property of Chinese Journal of Applied Ecology and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Soil aggregate stability is the most important indicator for assessing erosion resistance and soil fertility. In contrast, aggregates breakdown is the key step of rainfall splash erosion, where most particles transport and soils loss in water erosion. Surface electric field of soil particles can significantly affect soil aggregate stability, which can inevitably affect the rainfall splash erosion process. The purpose of this study was to clarify the effect of surface electric field on the size distribution of fragments resulting from aggregate breakdown, then to determine the relationship between fragments size distribution and splash erosion, and finally to identify which size fractions of aggregates fragment largely affect splash erosion during rainfall simulation. The Loessal and Lou soils were used from loess parent materials on Loess Plateau. According to the electric double layer theory, the electric field strength can be adjusted by the electrolyte concentration in the soil solution, which can affect the thickness of the diffuse double layer. Therefore, five electrolyte solutions (0.000 1, 0.001, 0.01, 0.1 and 1 mol·L-1 were selected to quantitatively adjust the electric field strength of particles. The aggregate stability was evaluated by the wetting sieving method, where the aggregates were immersed in different electrolyte concentrations of NaCl solution, and then sieved in the medium of alcohol with a set of sieves of 1, 0.5, 0.25 and 0.15 mm. The splash erosion was measured through the rainfall simulation experiment using the NaCl solution with different concentrations as rainfall materials. The results showed that: 1) The surface potential and electric field of the Loessal and Lou soils increased with the decrease of electrolyte concentration in bulk solution. Meanwhile, the aggregate stability decreased, whereas the amount of splash erosion increased; 2) When the electrolyte concentration was lower than 0.01 mol/L, or the surface potentials of Loessal and Lou soil were higher than 202.0 mV and 231.6 mV, respectively, the aggregate stability and splash erosion amount nearly kept constant, indicating that the surface potentials of 202.0 mV and 231.6 mV were the critical potentials for the aggregate breakdown and splash erosion of Loessal soil and Lou soil, respectively; 3) With the decrease of the surface electric field strength of soil particles, the content of particles in the diameter less than 0.15 mm that released from aggregates decreased, whereas the content of the large aggregates (>0.25 mm) increased, suggesting that the aggregates tended to break into the larger fractions as electric field strength decreased; 4) The amount of the splash erosion was positively correlated with the content of particles in the diameter less than 0.15mm that released from aggregates, while negatively correlated with the content of the large aggregates (>0.25 mm). This revealed that the fragmentation characteristics of the aggregate breakdown under the electric field have important effects on the rainfall splash erosion. The findings indicated that as the rainfall enters into the soil, the soil bulk solution is diluted; at the same time, the strong electric field immediately generated from the soil particles surface, which will essentially affect the degree of aggregate breakdown, thereby influence the process of splash erosion. This study can enrich our understanding of the rainfall splash erosion, and also provide the theoretical basis for regulating the soil aggregate stability and rainfall erosion [ABSTRACT FROM AUTHOR]