نتایج جستجو برای: water erosion

تعداد نتایج: 575644  

پایان نامه :وزارت علوم، تحقیقات و فناوری - دانشگاه تربیت مدرس - دانشکده علوم انسانی 1389

rivers and runoff have always been of interest to human beings. in order to make use of the proper water resources, human societies, industrial and agricultural centers, etc. have usually been established near rivers. as the time goes on, these societies developed, and therefore water resources were extracted more and more. consequently, conditions of water quality of the rivers experienced rap...

2016
Degen Lin Hao Guo Fang Lian Yuan Gao Yaojie Yue Luis Loures

Water erosion causes reduced farmland productivity, and with a longer period of cultivation, agricultural productivity becomes increasingly vulnerable. The vulnerability of farmland productivity needs assessment due to long-term water erosion. The key to quantitative assessment is to propose a quantitative method with water loss scenarios to calculate productivity losses due to long-term water ...

Journal: :مرتع و آبخیزداری 0
محمد اکبریان مربی دانشگاه هرمزگان، ایران سیّد حسن کابلی دانش آموخته دکتری مرتعداری، دانشکده منابع طبیعی، دانشگاه تهران، ایران. نوازاله مرادی مربی دانشگاه هرمزگان، ایران.

determining the relative sensitivity of land to erosion and its factors, could be the basis of soil conservation programs. the aim of this study is to compare water and wind erosion functions in land degradation of dasht-e-jeihoon using psiac and irifr.ea models and the source studying of aeolian sediments in geomorphologic facieses as homogeneous units. the results indicate that in dasht-e-jei...

Journal: :desert 2008
a. esmaili h. ahmadi s. feiznia j. ghoddoussi

soil erosion results from an interaction of several parameters, which vary in space and time. awareness ofenvironmental changes and their impact on the intensity and spatial pattern of water erosion can effectively help inrecognition of erosional reactions versus the affecting factors. the aim of this paper is to describe the development ofa methodology based on present knowledge and available ...

2003
DAVID D. BRESHEARS JEFFREY J. WHICKER MATHEW P. JOHANSEN JOHN E. PINDER

Soil erosion is an important process in dryland ecosystems, yet measurements and comparisons of wind and water erosion within and among such ecosystems are lacking. Here we compare wind erosion and transport field measurements with water erosion and transport from rainfall-simulation for three different semi-arid ecosystems: a shrubland near Carlsbad, New Mexico; a grassland near Denver, Colora...

2002
Renata Chmelová Bořivoj Šarapatka

According to a UN Environment Programme survey, topsoil is eroding faster than it forms on about one third of the world’s cropland, causing an estimated 85 % of the world s land degradation from human activities. Erosion of soil, mainly by water, is also a problem in the Czech Republic where 54 % of arable land is endangered by water erosion. The topic of this article is to describe contemporar...

Journal: :desert 2011
h. ahmadi s. taheri s. feiznia h. azarnivand

water erosion is a major environmental problem in many parts of the world. majority of semi-arid countries are concerned because of their specific climate and soils sensitivity, but also because of the recent intensification of human activities and agricultural practices. accurate estimation of water erosion for various land-use and climate scenarios is so an important key to define sustainable...

2017
Carlos Chávez Carlos Fuentes Fernando Brambila

Currently gravity irrigation remains the most widely used in agricultural areas and 90 percent of plantings, the water is applied to the plots by gravity. One of the main problems with these systems is erosion, which is a by product of the erosive forces of water over the row, which brings soil loss and therefore decreases in crop yield. Erosion is the removal of surface soil material caused by...

Journal: :international journal of environmental research 2014
a.m. martínez-graña j.l. goy c. zazo

this paper presents a mapping procedure for risk mapping of water and wind erosion, whichhelps to identify protective measures needed in the planning and management of natural parks. the map of water erosion risk was developed by combining the original and revised universal soil loss equation methodologies (usle-rusle), and the map of wind erosion risk was developed using quirantes’ method. usi...

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