نتایج جستجو برای: soil erosion is a serious environmental problem in vazroud watershed

تعداد نتایج: 20677608  

2001
Shunxiang Wu

Multiple-objective decision making (MODEM) provides an effective framework for integrated resource assessment of agroecosystems. Two elements of integrated assessment are discussed and illustrated: (1) adding noneconomic objectives as constraints in an optimization problem; and (2) evaluating tradeoffs among competing objectives using the efficiency frontier for objectives. These elements are i...

2005
Guobin Liu Junliang Tian Yumin Chen Puling Liu

The Loess Plateau is well known for its deep loess deposits and serious soil erosion. This paper analyses the characteristic of soil erosion on the Plateau and reviews the small watershed management and ecosystem rehabilitation practice and development in the future. In the last 30 years, the government has paid great attention on the integrated small watershed management and restoration of the...

Soil erosion is one of the vital factors contributing to the loss of fertility and environmental degradation. Generally accepted diagnostics of eroded soils is based on comparison of the sloping soils profile depth with the watershed soils. In this case, there is a separate problem of slope soils with a naturally shortened profile and eroded soils. Formation of the soil’s natura...

Journal: :journal of agricultural science and technology 0
h. asadi department of soil science, faculty of agricultural engineering and technology, university of tehran, karaj, islamic republic of iran. m. honarmand department of soil science, faculty of agricultural sciences, university of guilan, rasht, islamic republic of iran. m. vazifedoust department of soil science, faculty of agricultural sciences, university of guilan, rasht, islamic republic of iran. a. moussavi department of soil science, faculty of agricultural sciences, university of guilan, rasht, islamic republic of iran.

risk assessment of soil erosion, one of the most important land degradation problems worldwide, is very essential for land and water resources management, and development of soil conservation methods. in the present study, the temporal changes of soil erosion risk were assessed from 1987 to 2010, based on the revised universal soil loss equation (rusle) using remote sensing (rs) and geographic ...

پایان نامه :وزارت علوم، تحقیقات و فناوری - دانشگاه مازندران 1388

some researches made in the field of agency problem issue, deal with the role of control systems regarding owners and managers. in this research the relationship between the two control mechanisms, namely the voluntary disclosure (external control mechanism) and outside directors (internal control mechanism), which are reductive of agency problems, has been studied. for this reason, a sample ...

2002
He Binghui

The Three Gorges Reservoir Area is one of the most severe soil erosion in China. Serious erosion has degraded the soil productivity, deteriorated the ecological environment, and influenced the service life of Three Gorges Reservoir. The natural and social-economic factors which influence the soil erosion in Three Gorges Reservoir Area include topography, geological situation, vegetation, rainfa...

2005
Guobin Fu Shulin Chen Donald K. McCool

The revised universal soil loss equation (RUSLE), the sediment delivery distributed (SEDD) model, and ArcView GIS were used to estimate the impacts of no-till practice on soil erosion and sediment yield in Pataha Creek Watershed, a typical dryland agricultural watershed in southeastern Washington. The results showed that the average cell soil loss decreased from 11.09 to 3.10 t/ha yr for the wh...

پایان نامه :0 1374

this thesis is based upon the works of samuel beckett. one of the greatest writers of contemporary literature. here, i have tried to focus on one of the main themes in becketts works: the search for the real "me" or the real self, which is not only a problem to be solved for beckett man but also for each of us. i have tried to show becketts techniques in approaching this unattainable goal, base...

پایان نامه :وزارت علوم، تحقیقات و فناوری - دانشگاه شیراز - دانشکده علوم 1390

any change in the refractive index of a laser active medium can lead to serious degradation of beam quality, laser beam modes, laser performance and variation in the intensity distribution. alteration in the refractive index of laser active medium is especially notable in high power lasers. it is clear that in the laser beam production, the pumping agent induces a great amount of heat which...

Journal: :مدیریت خاک و تولید پایدار 0
حیدر غفاری دانشگاه تهران منوچهر گرجی دانشگاه تهران

maintaining soil productivity is one of the key factors in sustainable agriculture. soil erosion reduces soil productivity over a long-term period of time. therefore, determining soil erosion tolerance is necessary for sustainable agriculture production. in this study, the long-term effects of erosion on soil productivity in the typical kohin watershed were evaluated. the soil productivity inde...

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