introduction crop productivity is highly constrained by water and nitrogen limitations in many areas of the world (kalra et al., 2007). therefore, there is a need to investigate more on nitrogen and water management to achieve higher production as well as quality. irrigated sugar beet in the cropping systems of khorasan province in northeastern of iran accounts for about 34% of the land area un...

Fresh water supply and its security encounter a high level of fluctuating variability under global climate changes. To address these concerns in catchment water management, a good understanding of land use/cover impacts on the hydrological cycle affecting water supply is crucial. The objective of this study is to define a model to investigate the impact of existing land use/cover on water yield...

the adequacy of the swat model in the estimation of runoff, sediment yield and nitrate loss in the gorganrood watershed was tested, using the existing spatial database as the primary data. the model was then executed for a 31-years’ time period. in combination with the swat model, the sequential uncertainty fitting program (swat-cup and sufi-2) was added used to calibrate and validate a hydrolo...

hargraves-samani method is one of the methods for calculating plant evapotranspiration that needs minimum meteorological data. in order to evaluate et-hs model in determining sugar beet crop water demand in isfahan, an experiment was conducted at research field of department of agriculture, khorasgan branch, islamic azad university, isfahan, iranin 2005. the study was based a randomized complet...

abstract in order to evaluation the effects of price policies (wheat guarantee price in each period and its price lag), environmental (planted area) and climatic (min and max average temperature, total annual precipitation, cold-day degree and hot-day degree) factors, we considered wheat yield in razavi-khorasan province (9 cities) for a 13-year statistical period (1371-72 to 1383-84). in this ...