Study on Optimal Irrigation Index of Cotton with Drip Irrigation under Film Mulching based on Pan Evaporation

摘要

The objective of this paper is to find a simple and efficient drip irrigation schedule for cotton under film mulching using a homemade evaporation pan with a diameter of 60 cm. A field experiment was conducted to study the responses of cotton growth, seed cotton yield, water consumption and water use efficiency to drip irrigation amounts of 0.5 Ep (pan evaporation), 0.7 Ep and 1.0 Ep at the Irrigation Experiment Station of the Water-conservancy Bureau in Xinjiang Production and Construction Corps in Urumqi, Xinjiang province during the cotton growing seasons of 2007 and 2009. The feasibility of the drip irrigation scheme based on surface water evaporation by using a homemade evaporation pan was analyzed. The results showed that continuous water deficit at the bud and boll stages (irrigation quota equal to 0.5 Ep) produced negative effects on cotton growth, seed cotton yield and the water consumption process during the entire cotton growth period with drip irrigation under mulching compared to the sufficient irrigation treatment (irrigation quota equal to 1.0 Ep); the effect of timely and appropriate water deficit during the bud and boll stages (irrigation quota equal to 0.7 Ep and 0.5 Ep, respectively) on seed cotton yield was not significant; 22.78%~24.88% of the irrigation water was saved, while irrigation water use efficiency was improved by 27.94%~34.85%. It is suggested that the irrigation model with light water deficit during bud emergence (irrigation quota equal to 0.7 Ep), severe water deficit at the late flowering and boll stage (irrigation quota equal to 0.5 Ep), and sufficient water supply at the early flowering and boll stage (irrigation quota equal to1.0 Ep) is a convenient, high-quality, efficient drip irrigation pattern that can be used as a suitable irrigation approach to cotton production with drip irrigation under film mulching in Xinjiang.