نتایج جستجو برای: soil stability
تعداد نتایج: 476090 فیلتر نتایج به سال:
reported resistance values of 2,8 to 3,2 MPa for tillage pans in A long term trial to study the sustainability of a vertisol under continuous spgarcane monocropping was commenced in 1939 at the Experiment Station of the South African Sugar Association. The design of the trial consists of four replications of two main plots, each split into four sub-plots. The treatments comprise various combina...
Knowledge about the spatio-temporal variability of soil moisture is essential to understand and predict processes in climate science and hydrology. A significant body of literature exists on the characterization of the spatial variability and the rank stability (also called temporal stability) of absolute soil moisture. Yet previous studies were generally based on short-term measurement campaig...
Based on shear strength reduction finite element method, stability of retaining wall with relieving plate has been analyzed. Due to the structure character of retaining wall with relieving plate, it can be found that fracture surface could hardly cross the triangle area of between lower wall and soleplate, between upper wall and relieving plate, so the second fractured surface occurred at there...
In the long-term, wind erosion has considerable impact on rangelands. The aim of this study is to understand the changes of Hanitiyeh Rangelands located 30 kilometers east of Ahvaz and its function. Two transects, 42 meters in length, in wind gradient, patch and inter patch with 5 repeats that included shrub log complex, bush, grass, shrub, shrub-grass and bare open soil were measured. In addit...
A framework alternative to that of classical slope stability analysis is developed, wherein the soil mass is treated as a continuum and in-situ soil stresses and strengths are computed accurately using inelastic "nite element methods with general constitutive models. Within this framework, two alternative methods of stability analysis are presented. In the "rst, the strength characteristics of ...
Soil erosion is of the most important environmental challenges and factors of forest damage, which is, occur because of the land use change, road construction and lack of vegetation cover. Forest soil is naturally penetrable but forest roads are not. This issue causes the flows runoff on road surface and washes soil particles. Thus, forest roads must be planned and constructed accurately. So, t...
BACKGROUND Claims about the environmental benefits of charring biomass and applying the resulting "biochar" to soil are impressive. If true, they could influence land management worldwide. Alleged benefits include increased crop yields, soil fertility, and water-holding capacity; the most widely discussed idea is that applying biochar to soil will mitigate climate change. This claim rests on th...
Global urbanization is a vital process shaping terrestrial ecosystems but its effects on forest soil carbon (C) dynamics are still not well defined. To clarify the effects of urbanization on soil organic carbon (SOC) variation, 306 soil samples were collected and analyzed under two urban–rural gradients, defined according to human disturbance time and ring road development in Changchun, northea...
A new practical and precise method for determining soil aggregate stability is described. Four air-dry aggregate fractions (<0.25, 0.25 0.5, 0.5 1.0 and 1.0 2.0 mm) were added to thoroughly stirred water in a Mastersizer 2000 laser diffractometer. The suspension obtained was passed directly through the measuring system. The dynamics of median (equivalent diameter d50) particle-size distribution...
The spatial and temporal stability of soil test values is important to the use of soil testing for nutrient management. A study was conducted to evaluate the spatial and temporal stability of soil test phosphorus (P). Five sites ranging in size fiom 9.1 to 10.8 acres were soil sampled in the same locations in a 60 X 60 ft. grid either three or four times over a two year period. Bray 1 -P values...
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