Effects Of Irrigation Frequency On Moisture And Salt Regime And Water Production Function Of Cotton Under Mulched Drip Irrigation

This article deals with problems of irrigation frequency and crop-water production function of cotton under mulched drip irrigation in agriculture production. The results will be useful to cotton production under mulched drip irrigation in high salinity soil and to efficient use of water resource. The contents of this paper include two parts. Firstly, the influences of irrigation application frequencies on the soil salt regimes and cotton growth under mulched drip irrigation was investigated. Field experiments were arranged with the following treatments: 2 levels of soil salinity (0.08% and 0.8%), 2 irrigation application frequencies (one irrigation every 2 and 6 days during the stage of blooming-boiling). The experimental results showed that with the same amount of water irrigated, higher frequency irrigation to the soil of higher salinity during the stage of blooming-boiling reduced effectively the salinity level of the wetted soil body and increased yield by 28%. While the higher frequency of irrigation in the soil of lower saline level had no significant impacts on the growth and yield of cotton grown. But in the second year salinity in the high salt level soil reduced from 0.8% to 0.49% at 0~30cm, and the yield increased by 39%. While the higher frequency of irrigation had no significant impacts on the growth and yield of cotton grown in both saline soil levels. The ETa of each stage for cotton under mulched drip irrigation was estimated. Secondly, for the study of water production function of cotton under mulched drip irrigation, the cotton growth was divided into four stages. And two water treatments were used in every growth stage. So there are 9 treatments include control, totally. The water stress index of the commonly accepted model of water production function was calculated. The results showed that for cotton under mulched drip irrigation the water stress index during buding phase reaches the highest value and during flowering phase reaches the second highest value and the value is the lowest in open boll phase.