نتایج جستجو برای: fallow lands and forest in central zones

تعداد نتایج: 21788340  

2014
Emmanuel Acheampong Kwame Nkrumah

The widespread acquisition of land for large-scale/commercial production of biofuel crops in Ghana has raised concerns from civil society organizations, local communities and other parties, regarding the impact of these investments on local livelihoods. This paper assessed the effect of large-scale acquisition of land for production of Jatropha curcas on farmers’ livelihoods in Ghana. The study...

2001
David James Lewis

In presenting this thesis in partial fulfillment of the requirements for an advanced degree at The University of Maine, I agree that the Library shall make it freely available for inspection. I further agree that permission for " fair use " copying of this thesis for scholarly purposes may be granted by the Librarian. It is understood that any copying or publication of this thesis for financial...

Journal: :پژوهش های حبوبات ایران 0
احمد نظامی عبدالرضا باقری مرتضی عظیم زاده علی اکبر محمودی علی بزرگمهر

long term use of fallow in wheat-based cropping system of dry and semi-dry lands can increase erosion and decrease soil fertility. legumes as substituting crops for fallow could improve sustainability in this area. this study was conducted to evaluate the substituting of some legumes for fallow in a 2-yr wheat rotation at research stations in north khorasan province (natural resources research ...

2004
Francisco Suárez Vicente Garza Juan J. Oñate Manuel B. Morales

Maintaining winter stubble for the conservation of steppe passerines is widely implemented under the regional agrienvironmental program in Spanish dry lands. The adequacy of such measures was assessed in terms of bird density on different soil cover types in central Spain. Highest bird densities were found in ploughed, sown and fallow plots. Stubble plots were poorly used by wintering passerine...

Journal: Desert 2006
A. Kelarestaghi, H. Ahmadi M. Jafari

Land use change may influence many natural phenomena and ecological processes, including runoff, soil erosion, sedimentation and soil conditions. Decreasing of forest area in the North of Iran is one of the critical problems in recent years. The aims of this study are to detect land use changes between 1967 to 2002 using satellite images of Land Sat 7 ETM+ (2002), aerial photos and digital topo...

2017
Ariel E. Lugo Heather E. Erickson

Tropical and subtropical dry forest life zones support forests with lower stature and species richness than do tropical and subtropical life zones with greater water availability. The number of naturalized species that can thrive and mix with native species to form novel forests in dry forest conditions in Puerto Rico and the US Virgin Islands is lower than in other insular life zones. These no...

2014
Carina Van der Laan Pita A Verweij Marcela J Quiñones André PC Faaij

BACKGROUND Land use and land cover change occurring in tropical forest landscapes contributes substantially to carbon emissions. Better insights into the spatial variation of aboveground biomass is therefore needed. By means of multiple statistical tests, including geographically weighted regression, we analysed the effects of eight variables on the regional spatial variation of aboveground bio...

پایان نامه :وزارت علوم، تحقیقات و فناوری - دانشگاه صنعتی اصفهان - دانشکده ریاضی 1390

abstract: in the paper of black and scholes (1973) a closed form solution for the price of a european option is derived . as extension to the black and scholes model with constant volatility, option pricing model with time varying volatility have been suggested within the frame work of generalized autoregressive conditional heteroskedasticity (garch) . these processes can explain a number of em...

Journal: :پژوهش های جغرافیای طبیعی 0
مهری برومند کارشناس ارشد گروه علوم خاک، دانشگاه علوم کشاورزی و منابع طبیعی ساری مهدی قاجار سپانلو دانشیار گروه علوم خاک، دانشگاه علوم کشاورزی و منابع طبیعی ساری محمد علی بهمنیار استاد گروه علوم خاک، دانشگاه علوم کشاورزی و منابع طبیعی ساری سروش سالک گیلانی مربی گروه علوم خاک، دانشگاه علوم کشاورزی و منابع طبیعی ساری

introduction land use change and its effects on soils is one of the important factors that decrease soil quality. nowadays because of rapid growth of population, vast forest areas are changed into agricultural lands but chemical properties of the soils are commonly affected by changes in land usage.  converting the forest areas into agricultural lands is one of the prevalent issues in iran, esp...

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