Effects Of Water-Nitrogen Coupling On Winter Wheat Growth And Yield

Different water and nitrogen coupling have great effects on growth and yield of winterwheat. Water and nitrogen are the necessary substance of crop growth.The study of optimumwater-nitrogen spatial coupling had important significance in saving water and improvingcrop economic value. Taking wheat as experimental material, this paper researched the effectof different irrigation and fertilization treatments on plant height, dry matter weight, leaf area,root distribution characters and yield. The primary results were as follows:1. The winter wheat grew exuberantly and water demand was great during jointingstage, so water deficit would seriously affect growth of wheat. With the increase of nitrogenfertilizer, the winter wheat height increased during returning green and jointing stage.Different had significant effect on leaf area under the same nitrogen fertilizer, and the leafarea reached the maximum rate under the treatment of W₂₂₅₀（meaning irrigation water is2250cubic meters per hectare） after jointing stage.2. With the change of light intensity, diurnal course of photosynthetic rate of winterwheat leaves all presented single-peak pattern or two-peak pattern during jointing stage underdifferent irrigation and fertilization treatments. Water deficit would reduce photosynthetic ratewhile increase of fertilizer nitrogen rate raised photosynthetic rate. The chlorophyll contentsrose with increasing nitrogen levels and water deficit could cut down chlorophyll contents;the effect of fertilizer nitrogen was greater than irrigation.3. The content of nitrate nitrogen was generally below25mg/kg, and nitrate nitrogencontent reached maximum in0-20cm （meaning20cm in the ground） soil depth. The resultsshowed that the promotion effect of W₁₅₅₀and N₂₂₅（meaning irrigation water is2250cubicmeters per hectare, nitrogen is225kg per hectare） treatment was bigger than othertreatments.4. Under the same irrigation, increasing of nitrogen fertilizer properly could promote theroot growth and yield of winter wheat, however, when the nitrogen fertilizer exceeded thedemand of wheat150Kg/hm²（Nitrogen to225kilograms per hectare）, it would inhibit rootgrowth and wheat yield. The reducing of water irrigation could significantly promote rootgrowth under the same nitrogen fertilizer.5. The results showed that the relation of yield and root shoot ratio was unitary and quadratic relationship. Comprehensive analysis, under the given experimental condition, thetreatment of irrigation1500m³/hm²and nitrogen fertilizer150kg/hm²is the best coupling.