نتایج جستجو برای: undesirable change in soil
تعداد نتایج: 17076976 فیلتر نتایج به سال:
In this article, we introduce two community-contributed data envelopment analysis commands for measuring technical efficiency and productivity change in Stata. Over the last decades, an important theoretical progression of analysis, a nonparametric method widely used to assess performance decision-making units, is incorporation undesirable outputs. Models able deal with outputs have been develo...
to explore the idea the investingation proposed, aimed at finding whether the performances of the population of iranians students studying english in an efl context are consistent in l1 and l2 writing taks and whether there is a cross-linguistic transfer in this respect. in this regard the subjects were instructed to write four compositions-two in english and two in farsi-which consisted of an ...
Land use change is an important issue in Iran, especially in the north of the country. In the present research, effect of changing land use from rangeland to cropland and garden on some physical and chemical characteristics of soil, was studied in Babolrood Watershed in southern part of Babol, Eastern Bandpey in Mazandaran province. For each land use, soil samples were collected from 2 depths a...
The soil quality is defined as the ability of soil to function as an essential part of the human habitat. In this study, the effects of land use change (conversion of forest lands into agricultural lands) on the soil physical quality were studied in the Gilan-e-Gharb region. For this study, soil samples were collected from surface and subsurface layers of both land uses, and the peak and should...
abstract in this study the effects of land use changes from pasturelands to croplands on soil microbiological and biochemical properties were studied in kangaver, dehno and soltanye regions. composite soil samples from 0-20 and 20-40 cm depths of pasture and cultivated lands were taken from kangaver, dehno and soltanye regions, and soil microbial respiration, microbial biomass c and n, and urea...
Two selection goals of inclusion or exclusion of calving interval (CI) in the selection goal function for Holstein cows in Iran, besides milk yield, milk fat percentage, and milk protein percentage, were studied. Four selection indices were composed of using the information on production traits, CI and / or days from calving to first insemination (DFI). The results of the predicted genetic grow...
In arid and semi-arid regions, soil surface warming is a considerable phenomenon causing a high thermal gradient which makes water flow intensely. The degree of soil temperature is effective on crop production, plant growth and soil microorganisms. In recent years, the ascending trend of temperature has been substantially noticed by researchers in the issues of pointwise climate change and at w...
BACKGROUND: While recognizing the economic obstacles that currently block widespread use, many concerned with improving agricultural productivity and food security in Sub-Saharan Africa (SSA) are focusing on fertilizer as a remedy for declining soil quality and stagnant yields. Some have suggested that SSA needs to increase fertilizer use from 9 to at least 30 kg/ha during the next decade. Othe...
Soil erosion continues to be a threat to agricultural productivity worldwide, with soil losses in the United States exceeding 3 billion tons annually. Wind and water erosion have caused dramatic declines in soil productivity. Erosion protection and associated conservation of nutrients, organic matter, soil water holding capacity and biota are significant concerns. Pimentel et al. (1995) estimat...
Improper tillage with no manure may cause a range of undesirable processes (destruction of soil structure, accelerate erosion, depletion of organic matter and fertility). A field experiment was conducted to observe the change in soil properties after incorporation of green manure crops and to find out the residual effect of green manure crops along with tillage on maize and rice yields during 2...
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