Effects Of Water And Nitrogen On Yield And Quality Of Vegetables And Soil Environment

Aming at the facts of vegetables quality decreasing and environment pollution risk arising due to unreasonable irrigation and fertilization, in this experiment, effects of 5 soil moisture levels(50～60%,60～70%,70～80%,80～90%,90～100% of field moisture capacity)on water consumption and yield of summer squash in solar greenhouse,effects of 6 nitrogen levels (0,61.71,123.43,185.14,246.86,308.57 kg/hm2 of pure nitrogen) on yield,quality and soil NO3 ? ?N content of cabbage,couple effects of water(30～40%,45～55%,60～70%,75～85%,90～100% of field moisture capacity) and nitrogen (61.71,123.43,185.14 kg/hm2 of pure nitrogen)on yield,quality and soil environment of cowpea in solar greenhouse were studied. The main results as follow:1. Under 70%～80%(W3)relative soil moisture, yield of summer squash was highest. It concluded that soil water content should be controlled under 70%～80% of field moisture content in order to utilize water resources reasonably.2. NO3 ? ?Ncontents of cabbage and soil increased with the nitrogen levels arise. However, Vc and soluble sugar content of fresh cabbage decreased with the increasing of nitrogen. Yield of cabbage was highest under nitrogen fertilizer as 185.14 kg/hm2(N4). For human health, nitrogen level should be maintained around 185.14 kg/hm2.3. The yield of cowpea was advanced under coordination between water and nitrogen and up to highest under W3N2 (60～70% of field moisture capacity and 123.43 kg/hm2 of pure nitrogen). Soluble sugar content was advanced by nitrogen supply increasing, and up to highest under W4N3,but influenced little by soil moisture. Vc content of cowpea arised the peak under W3N2, but deceased when levels of water and nitrogen were too high or too low. NO3 ? ?N content of cowpea was improved with water and nitrogen level increasing.4. At the early-pod stage after blossoming, soil respiration reached peak under W2N2, but showed peak values under W3N2 at blossoming stage; the activities of urease and alkaline phosphatase were inhibited with the increasing of water and nitrogen. The invertase activity was advanced under moderate levels of water and nitrogen. Organic matter and available N in soil were advanced a little with water and nitrogen increased properly; available K and available P in soil were decreased with water and nitrogen levels arised.5. The optimum results derived from nitrogen123.43 kg/hm2 of pure nitrogen and water 60～70% of field moisture capacity by considering all index.