نتایج جستجو برای: cultivated land size
تعداد نتایج: 687875 فیلتر نتایج به سال:
the discharge of total suspended sediments (tss) and dissolved nutrients from watersheds into receiving waters is a serious problem when natural vegetation is degraded by agriculture or overgrazing. this study was conducted in soolegan watershed to investigate land use change and overgrazing effects on phosphorus loss (dissolved & particulate), particle size associated loss of p and effect of t...
Cultivated land has been feeding the world for thousands of years. Only in the last few decades, remote sensing is used to assess and monitor the extent and status of cultivated land. One of the greatest challenges when working with existing land cover datasets is the lack of consistent and reliable data on the location and area intensity of cultivation. By most counts land cover datasets ident...
In China there is a growing debate on the role of cultivated land conversion on food security. This paper uses satellite images to examine the changes of the area of cultivated land and its potential agricultural productivity in China. We find that between 1986 and 2000 China recorded a net increase of cultivated land (+1.9%), which almost offset the decrease in average potential productivity, ...
Runoff, soil loss, sediment concentration, and particle size distribution of sediment eroded by runoff events were measured between 1976 and 2000 from 5 small agricultural watersheds on Vertisols at ICRISAT Center, Patancheru, India. The effects of storm size and land management system on total soil loss and size distribution of sediment during runoff are discussed. At the beginning of runoff e...
Based on the background of construct the national grain strategy project of Henan province core and construct Zhongyuan Economic Zone, considering the Henan province's cultivated land resources use efficiency and food security, using multiple linear regression model and the principal component analysis to analyze the cultivated land resources’ use efficiency between 1999-2008 of Henan province,...
In order to study the effects of different land uses on soil development, a loess hillslope was selected in Agh-Su area, eastern Golestan Province. Six profiles in four land uses including pasture, Quercuse natural forest, Cupressus artificial forest and a cultivated land, were dug and studied. Samples from different horizons were collected for physico-chemical and microscopic analyses. Importa...
Organic carbon pools and carbon lability directly affect soil biological, physical and chemical characteristics. Besides, capacity of self-organization of soil is related to the organic carbon pools. Sand size fraction (> 50 µm) organic matter is more labile than silt+clay size fraction organic matter. Assessment of this organic carbon variation can be a suitable index to determine soil quality...
Under rapid urban sprawl in Northeast China, land conversions are not only encroaching on the quantity of cultivated lands, but also posing a great threat to black soil conservation and food security. This study's aim is to explore the spatial relationship between comprehensive cultivated soil heavy metal pollution and peri-urban land use patterns in the black soil region. We applied spatial la...
When agroecology is considered, the hill regions are divided into three (Table 1.1) resulting in five distinct domains that vary in their resource endowment, land-use systems, farming systems, cropping patterns and intensities, and access to road and market networks. Population distribution in Nepal is related more to the proportion of cultivated land than to the geographical area. For example,...
The rapid development of agricultural modernization in Hubei province has an influence on cultivated land resources variations to a certain degree. This paper used grey relational analysis method,combined with Hubei province cultivated land area decreased data within the year covering 2000 to 2010 and agricultural modernization development index data, then analyzed the influence relationship be...
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