Study On Water And Fertilizer Coupled Mode Of Maize Under Mulched Drip Irrigation In The West Of Heilongjiang Province

Heilongjiang province is an important grain producing area in China, maize is one of the main local crops. However, Heilongjiang has a lower accumulated temperature, natural disasters like cold spring and drought often occure, soil fertility is falling as well. Farmers’ inappropriate irrigation and fertilization application method have caused great waste of water and fertilizer. These problems seriously restrict the development of agriculture. Drip irrigation under plastic can effectively increase the soil temperature, improve soil moisture, and achieve the goal of saving water and fertilizer and high yield at the same time,it is of great importance to high crop yield and food safety of Heilongjiang province.In this study, a field experiment was carried out to study effects of different water and fertilizer on growth, yield, yield components, water consuming law and WUE of maize by D-311 optimized saturated design. 5 levels of water, N&P were set, respectively. Economic benefits were analyzed. The results are as follows:(1) N and P can improve maize height effectively.Water and N can improve stem diameter effectively. P mainly effects leaf growth before tasseling stage, and N mainly effects leaf growth after tasseling stage.(2) The impact order of water and fertilizer on yield is: N>water>P, and effect of N and water is far greater than that of P. When amount of N,P and water are 345kg/hm2, 81.819kg/hm2 and 200m3/hm2, yield reaches the maximum, 13956kg/hm2. The correlation coefficients between panicle length, kernels per row, bare tip length, grains weight per spike and maize yield are high, correlations between panicle length, kernels per row, bare tip length and yield are significant at 0.05 level, correlation between grains weight per spike and yield is significant at 0.05 level.(3) Changing trend of 0-60 cm soil moisture content is: it decreases from seedling to jointing stage, increase from jointing to tasseling stage, and decreases again at mature stage. N can effectively promote the absorption of soil moisture in tasseling, filling and mature stage. Soil moisture content is low in 0-20 cm layer changes by big ranges, while 20-60 cm layer changes little., 20-30 cm changes little after jointing stage and it changes slower than its above and below layer. 30-60 cm layer is strongly influenced by 0-20 cm layer, and its changing lags behind 0-20 cm layer.(4) The impact order on WUE is: water>N>P, water has a negative effect while N&P have positive effect.The optimized application amount of N, water and P are 345kg/hm2, 200m3/hm2 and 65.45kg/hm2, respectively, considering yield, WUE and economic benefit. This mode is suitable to western part of Heilongjiang province, and applying this mode in large scale is also suggested.