نتایج جستجو برای: keywords:combination method evapotranspiration garliclysimeter

تعداد نتایج: 1635927  

2004
Raj Vir Singh

Wheat is an important crop of India. Precise estimates of evapotranspiration can be obtained by multiplying crop coefficients to reference evapotranspiration using readily available climatic data. PenmanMonteith equation is adopted world wide as the most reliable and accurate method for computing reference evapotranspiration. The Food and Agriculture Organization (FAO) presented crop coefficien...

2008
Tingting Shi Dexin Guan Anzhi Wang Jiabing Wu Changjie Jin Shijie Han

Forest evapotranspiration is one of the main components in the regional water budget. A comparison between measured and estimated eddy covariance (EC) data, considering the Katerji–Perrier (KP), Todorovic (TD) and Priestley–Taylor (PT) actual evapotranspiration methods, was carried out. These models, relying on more easily obtainable data, are valuable when long-term direct measurements are not...

2017
Chiara Corbari Giovanni Ravazzani Marta Galvagno Edoardo Cremonese Marco Mancini

The Food and Agricultural Organization (FAO) method for potential evapotranspiration assessment is based on the crop coefficient, which allows one to relate the reference evapotranspiration of well irrigated grass to the potential evapotranspiration of specific crops. The method was originally developed for cultivated species based on lysimeter measurements of potential evapotranspiration. Not ...

Journal: :iran agricultural research 2016
s. m. seyedian m. farasati o. bahmani j. sajad

abstract-different evapotranspiration (et) estimation equations having different accuracy with different conditions have been developed for et estimation. this study will firstly focus on the estimation of 13 climatic equations of daily garlic et estimation whose  et is measured by lysimeter to provide information which can be helpful in selecting an appropriate et equation. the paper aims at s...

2012
Songhao Shang

Crop water requirement is essential for agricultural water management, which is usually available for crop growing stages. However, crop water requirement values of monthly or weekly scales are more useful for water management. A method was proposed to downscale crop coefficient and water requirement from growing stage to substage scales, which is based on the interpolation of accumulated crop ...

Journal: :آب و خاک 0
شریفان شریفان علیزاده علیزاده

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...

2014
Jozsef Szilagyi

Theoretical considerations and empirical evidence indicate a linear relationship between the land surface temperature (Ts) and the corresponding evapotranspiration (ET) rate under spatially constant wind and net energy conditions at a homogeneous vegetated surface. Such a relationship lies at the core of the popular surface energy balance algorithm (SEBAL); the satellite-based energy balance ap...

Ali Assareh, Hadis Davoodi

In order to determine the required water for irrigation it is necessary to calculate the amount of needed water by plant or evapotranspiration. The equations that are used to calculate evapotranspiration are not applying the same climatic parameters and, due to their experimental nature, they are not suitable for all climatic conditions. In the present study in order to compare evapotranspirati...

The phenomenon of evapotranspiration causes water and moisture losses from water, soil and vegetation levels. Due to the small amount of atmospheric precipitation and water resource constraints in Iran, it is important to calculate it through a suitable method. The present research attempts to evaluate the evapotranspiration reference crop (ETo) and present it in the form of zoning map as a bas...

Evaluating potential evapotranspiration plays an important role in planning, designing, and managing water resources, especially in arid and semi arid zones. The aim of the present research is considering spatio-temporal changes of different potential evapotranspiration methods such as Thornthwaite, Hargreaves, and Blaney-Criddle in the Maharlou Watershed, Fars province. So, yearly statistics o...

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