abstract in order to estimate the reference evapotranspiration different equation is used. validity of each methods depends upon the climate and the parameters which are used in these equations. therefore it is necessary to calibrate these methods for any specific area and for any desired frequency. in this study common temperature and radiation based methods were used for calculating crop evap...

the objective of deficit irrigation is to increase water use efficiency by reducing of water quantity or wave off further irrigations that have not necessary. cotton plant is sensitive to irrigation timing and quantity through different growth stages. the field trail was conducted at hashemabad cotton research station (gorgan) to determine water consumption and cotton sensitivity to deficit irr...

this study was undertaken to identify morphological changes in young seedlings of 5 iranian almond species (prunus dulcis, p. eburnea, p. eleagnifolia, p. haussknechti, and p. scoparia) under polyethylene glycol-induced drought stress. drought stress caused a significant reduction in plant growth parameters such as fresh and dry weights of plant organs, leaf number, total leaf area, and leaf re...

in this research, amount of evaporation and transpiration and water requirement of wheat plant for marvdasht town (representation station: zaraghan) during 17-years statistical duration from 1989-2005 and properties of plant and soil are calculated using cropwat software. at the first, trends of dry and wet periods for mentioned station were determined using long-term average of climatic data (...

One of the effective steps in use of water resources is accurate estimation of plants water requirement. Lack of accurate estimation of this amount leads to water loss and failure to achieve optimum yield, reduced potential of production, soil resources degradation by too much irrigation or lack of enough leaching and salinization of soils by irrigation less than necessary level, which would ul...

shortage of water resources and increasing demand to consumption of this scarce resource, leads to somenoticeable limitations. on the other hand, population growth and consequently, increasing demand for water in aridand semi arid regions , needs production in exchange of little amount of water consumption. to approach thisobjective, an experiment in the complete randomized blocks carried out i...

in this research, the statistics of daily temperature of meteorology stations for estimating the probable occurrence of the first and last frost temperature, the phonological thresholds of saffron and its flowering and irrigation dates were explored. furthermore, by applying different methods, the probabilities of the attained dates in different probability levels were fit in smada software. th...

this paper reports the results of using three empirical methods (makkink, priestley-taylor and hargreaves) for estimating the reference evapotranspiration (et0) in the semi-arid region of tensift al haouz, marrakech (center of morocco). the penman-monteith equation, standardized by the food and agriculture organization (fao-pm), is used to evaluate the three empirical methods. the obtained et0 ...