نتایج جستجو برای: soil factors

تعداد نتایج: 1242692  

2016
Yu Shi Jonathan M. Adams Yingying Ni Teng Yang Xin Jing Litong Chen Jin-Sheng He Haiyan Chu

The biogeographical distribution of soil bacterial communities has been widely investigated. However, there has been little study of the biogeography of soil archaeal communities on a regional scale. Here, using high-throughput sequencing, we characterized the archaeal communities of 94 soil samples across the eastern Tibetan Plateau. Thaumarchaeota was the predominant archael phylum in all the...

2015
L. Ma C. Guo X. Lü S. Yuan R. Wang

Global environmental factors impact soil microbial communities and further affect organic matter decomposition, nutrient cycling and vegetation dynamic. However, little is known about the relative contributions of climate factors, soil properties, vegetation types, land management practices and spatial structure (which serves as a proxy for underlying effects of temperature and precipitation fo...

2000
F. Graef K. Stahr

Soil water availability is most essential in the Sahelian agriculture but is hampered by several factors. Surface crusts or crust-like surfaces, which are characteristic of most Sahelian soils, have been shown to decrease water in®ltrability and increase runoff. Their type and structure are in ̄uenced by soil texture, vegetation cover, erosion and deposition effects of wind and water. A soil and...

Journal: :international journal of environmental research 2012
b. basso l. de simone d. cammarano e.c. martin s. margiotta

the main factors affecting environmental sensitivity to degradation are soil, vegetation, climate and management, through either their intrinsic characteristics or by their interaction on the landscape. different levels of degradation risks may be observed in response to particular combinations of the aforementioned factors. for instance, the combination of inappropriate management practices a...

Journal: :Earth Science Informatics 2015
Md. Rejaur Rahman Zhihua Shi Chongfa Cai Dun Zhu

Soil erosion is one of the most serious environmental problems affecting the quality of soil, land, and water resources upon which humans depend for their sustenance. A soil erosion hazard map is highly useful for environmental planning, soil conservation and management in soil erosion prone areas. In order to assess the soil erosion hazard, remote sensing (RS) and geographical information syst...

2013
J. Sun G. W. Cheng W. P. Li

The Tibetan Plateau, known as the “world’s third pole” for its extremely harsh and fragile ecological environment, has attracted great attention because of its sensitivity to global changes. Alpine grassland on the Tibetan Plateau has an important function in the global carbon cycle. Many studies have examined the effects of various environmental factors on biomass distribution. In this study, ...

Journal: :ماشین های کشاورزی 0
احمد شریفی مالواجردی محمد یونسی الموتی احمد محسنی منش

soil compaction can occur as a result of a number of factors. one of the most important factors is soil response to pressures imposed by wheels and soil engaging tools. this research investigated the effect of tyre load and inflation pressure on soil compaction-related factors. these factors include rut width, rut depth, cone index and horizontal force in different layers of soil profile. in th...

2007
P. Tittonell K. D. Shepherd B. Vanlauwe K. E. Giller

To guide soil fertility investment programmes in sub-Saharan Africa, better understanding is needed of the relative importance of soil and crop management factors in determining smallholder crop yields and yield variability. Spatial variability in crop yields within farms is strongly influenced by variation in both current crop management (e.g. planting dates, fertilizer rates) and soil fertili...

Amin Zoratipour Hossein Azadi

Generally, the evaluation and assessment of the critical condition of rill formation are useful for a better understanding of soil erosion processes. The inherence characteristics of soils, which have much dynamic variations on the hillslopes and are affected by rill formation, are the soil critical shear stress and soil erodibility factors. This study aims to assess experimental rill incision ...

ژورنال: علوم آب و خاک 2011
احمد جلالیان, , حسین خادمی , , راینر شولین, , فرزاد ستوهیان, , محسن نائل, , محمود کلباسی, ,

Geologic and pedologic controls are the main factors determining the distribution of elements in natural soil environments. In order to assess the role of these factors in the content and distribution of major elements of soil, six parent materials including phyllite (Ph), tonalite (To), periditite (Pe), dolerite (Do), shale (Sh) and limestone (Li) were selected in Fuman-Masule region. Soil gen...

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