نتایج جستجو برای: far from agricultural lands therefore

تعداد نتایج: 5999716  

پایان نامه :وزارت علوم، تحقیقات و فناوری - دانشگاه یزد - دانشکده جغرافیا 1392

the west of esfahan province, iran, is one of the most important agricultural areas throughout the country due to the climate variability and life-giving water of zayanderood river. rice is one of the major and economic crops in this area. the most important climatic elements in agricultural activities which should be considered include temperature, relative humidity, precipitation and wind. so...

2004
Marc L. Imhoff Lahouari Bounoua Ruth DeFries William T. Lawrence David Stutzer Compton J. Tucker Taylor Ricketts

We use data from two satellites and a terrestrial carbon model to quantify the impact of urbanization on the carbon cycle and food production in the US as a result of reduced net primary productivity (NPP). Our results show that urbanization is taking place on the most fertile lands and hence has a disproportionately large overall negative impact on NPP. Urban land transformation in the US has ...

Ali-baygi, Amir-hossein, Ghanbar-ali, Rezvan,

Learning, development of technology and adoption of new agricultural methods would have great impact upon peasant productivity more specifically upon subsistent farmer’s status. This study aims to investigate the impact of agricultural extension program upon the performance of wheat producers in Kermanshah. Research statistical society includes 186 of wheat farmers who participated in the schoo...

2014
Bhartendu Pandey Qingling Zhang Karen C. Seto

Urban expansion is one of the major drivers of agricultural lands loss. However, current remote sensing-based efforts to monitor this process are limited to small scale case studies that require much user input. Given the rate and magnitude of contemporary urbanization, there is a need to develop a land change algorithm that can characterize the loss of agricultural land at large scales over lo...

Extended abstract 1- Introduction Changing the forests and pasture landuses to agricultural lands is one of the major global concerns about environmental degradation and climate change. As a result of the rangeland and forest changes into agricultural land and also tillage operations, about 430 million hectares, representing 30% of the world's total plowed land, are annually eroded and leavin...

Journal: :مرتع و آبخیزداری 0
غلامرضا زهتابیان استاد دانشکده منابع طبیعی، دانشگاه تهران حسن خسروی استادیار دانشکده منابع طبیعی، دانشگاه تهران علی آذره دانشجوی دکتری بیابان زدایی، دانشکده منابع طبیعی، دانشگاه تهران

need to increasing agricultural land in order to improve food resources in the past two centuries recentlead to widespread changes in land use and improper management of these lands. continue thisprocess can lead to land degradation and desertification, and improve such soils is very costly;therefore, prevention of land degradation is more desirable. this function requires to research on theuti...

مجید افیونی, , حسین خادمی, , منوچهر امینی, ,

Heavy metals including cadmium (Cd) and lead (Pb) are entering agricultural soils from different routes and mainly due to human activities. Accumulated Cd and Pb in the soil would eventually enter the human and animal food chains and pose threat to their health. Therefore, evaluating heavy metal accumulation is necessary to prevent soil and environmental pollutions and should be considered by r...

2002
Dengsheng Lu

Numerous classifiers have been developed and different classifiers have their own characteristics. Controversial results often occurred depending on the landscape complexity of the study area and the data used. Therefore, this paper aims to find a suitable classifier for the tropical land cover classification. Five classifiers – minimum distance classifier (MDC), maximum likelihood classifier (...

1999
R. M. Otsyina B. W. Norton M. Djimdé

Arid and semi-arid lands constitute a large proportion of available agricultural and rangeland in the world. These lands are characterised by low and unreliable rainfall, low land productivity, and low socioeconomic status of the inhabitants. Livestock plays a very significant role in their economies. Leguminous trees and shrubs, which dominate the natural rangelands, are often higher in crude ...

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