Primary Study on Water-nitrogen Coupling Effect on Cotton Plant in Condition of Film Mulch and Drip Irrigation

Single and multi-factors field experiments were conducted to explore the rule of cotton plant′s nitrogen absorption and water consuming under film mulch and drip irrigation,and nitrogen rate/irrigation coupling effect function was established as well.Our results illustrated that minor nitrogen was absorbed before budding whereas over 60% nitrogen was absorbed during flowering and boll-opening period.This suggested that it is reasonable to distribute most of the nitrogen fertilizer in form of top-dressing which is fit to cotton physiological demands.The average apparent water consuming capacity is 44mm in seedling,113mm in budding,280mm from omthesis to boll-opening period,the whole water consuming capacity in cotton all life is 437mm in Shihezi area in the condition of film mulch and drip irrigation.With the increase of the amount of irrigation, the cotton plant water consuming capacity is increased as well.Water-nitrogen coupling function was established by a multi-factors experiment,then we calculated that the maximum yield irrigation was 4189.5m~3/hm~2, and the maximum yield N application was 223.5kg/hm~2.spatial address searchingmethod was adopted to find the best economic yield,irrigation and N rate.We found that the yield,4560-5040kg/hm~2,occupied the biggest probability,and accordingly,the irrigation and N rate are 4125m~3/hm~2,205.5Nkg/hm~2 and 4170m~3/hm~2,223.5kg/hm~2.We then suggested that with 214.5kg/hm~2 N rate and 4125m~3/hm~2 irrigation is the best combination in the normal film mulch and drip irrigation cotton production.