Response Of Water And N Fertilizer Coupling On The Use Efficiency Of Water And Nutrient And Yield Of Maize In A Drip Irrigated Field

【Objective】 Water and nitrogen were two key factors limiting crop production in arid areas. However, the water and fertilizer consumption characteristics of corn under drip irrigation in the north slope area of Tianshan Mountain in Xinjiang remained unclear, the theory and technical support of continuous high and stable yields was deficient. Optimizing water and nitrogen supply is one of the effective ways to achieve high yield and high use efficiency of water and fertilizer, which can also provide theory basis for the popularization and application of the efficient utilization of water and nitrogen fertilizer under drip irrigation.【Method】 A field experiment including three water rates(4500, 6750, 9000 m3 / hm2) and five nitrogen rates(0, 225, 330, 435, 330 kg/hm2) was conducted, in order to investigate the effect of water and N fertilizer coupling on dry matter accumulation, absorb of nitrogen and phosphorus, and yield of high density(105000 plants/hm2) maize under drip irrigation. Dry matter distribution in different growing stage, the underground distribution of mineral nitrogen,, and the model of water and nitrogen coupling was also investigated.【Result】 1) Dry matter accumulation and nitrogen uptake of maize was significantly increase along with elevation of the irrigation and nitrogen levels, but decrease when the N application rate was more than 435 kg/hm2 and irrigation amount was more than 9000 m3/ hm2. The response of water treatment to maize dry matter accumulation at full ripeness period was: W6750(36359 kg/hm2) > W9000(35077 kg/hm2) > W4500(33451 kg/hm2), nitrogen treatment to maize nitrogen uptake was: N435(459.9 kg/hm2) > N540(458.1 kg/hm2) > N330(416.3 kg/hm2) > N225(351.3 kg/hm2).2) The largest N uptake rate increase with N application rate. The largest value was 6.57 kg. hm – 2. d – 1 when the N application rate was 435 kg/hm2.3) Irrigation and nitrogen fertilizer significantly increased maize production, spike grain number and grain weight.A positive interaction between water and nitrogen was observed.4) The maximum maize yield was 18072 kg/hm2 when N application rate was 567.0 kg N/hm2. The best economic N application rate was 427.9 ~ 467.7 kg N/hm2, and maize yield was up to 17109 ~ 17138 kg/hm2.【Conclusion】 1) The maximum of dry matter accumulation and nitrogen uptake of maize under drip irragation was appered from milk stage to grain formation stage. The largest nitrogen uptake of maize increased with N application rate, the time to reach maximum growth rate was shorten with the increase of N application. The nitrogen fertilizer use efficiency increased with N application rate at the range of 0 ~ 435 kg N/hm2, but decreased when N application rate was more than 435 kg N/hm2. Maize yield increased along with the N application rate, but significantly decreased with the increase of irrigation water. The suitable irrigation amount was 4500 ~ 6750 m3/hm2, and water productivity of irrigation can reach to 2.57 ~ 3.80 kg/m3.2) Water and nitrogen showed a positive interaction effect on high-density(> 105000 plants/ha) maize under drip irrigation in Northern Xinjiang,, the contribution of nitrogen fertilizer on maize yield was significantly greater than water. The super high yield of 17109 ~ 17138 kg/hm2 could be acquired when the water rate was 6750 m3/hm2 and the best economic N application rate was 427.9 ~ 467.7 kg N/hm2, meawhile, the nitrogen partial productivity and nitrogen use efficiency could be reach to 122 kg/N kg and 45.0% respectively.