Modelling of evapotranspiration and crop coefficient of cotton in northern Xinjiang

Evapotranspiration was estimated by crop coefficient method and Penman-Montieth model of drip and furrow irrigation in northern Xinjiang. Result showed crop coefficient consistented with the typical “S” curve. There was no significant difference of total evapotranspiration between drip and furrow irrigation. Dual crop coefficient approach was better than single crop coefficient approach in the cotton field. Furthermore, relationship between evapotranspiration and LAI was established and justified, thus this model could be used to simulate water demand of cotton field in arid area.