Research On Effect Of Water-nitrogen Coupling Of Oil Sunflower In A Drip-irrigated Multiple Cropping System

Object: In order to understand the research on effect of water-nitrogen coupling of oil sunflower in a drip-irrigated multiple cropping system and analysis the effects of water-nitrogen coupling on the growth and yield 、 photosynthesis characteristics and soil water use 、nutrient use of oil sunflower in a drip-irrigated multiple cropping system in the northern Xinjiang. In order to provides scientific basis for guide the production practice, improve water use efficiency and the development of scientific water and nitrogen control strategy of high yield and water saving and the of the popularization technology of oil sunflower drip irrigation in arid and semi arid area.Methods: Based on field experiment, combining laboratory experiment, local early maturing variety “new No.5 hybrid oil sunflower” taken as tested materials, conduct a three-level complete treatment plot experiment of factors of water and nitrogen under drop irrigation. 3 levels of pure nitrogen were set: 162、232 �'� 302kg·hm-2; 3 levels of irrigation were set: 2100、3000 �'� 3900m3·hm-2. The trial was designed with 9 treatments, each with 3 replicates.Results:(1) The coupling effect of irrigation and nitrogen fertilizer on the growth traits and yield of the oil sunflower in a drip-irrigated multiple cropping system was very significant. The growth and fade rate of leaves, the growth rate of plant height, and the accumulation rate of dry matter were the important factors that affected the growth and yield of the plants. Under the experimental conditions, the growth index of irrigation 3000m3·hm2、pure nitrogen 232kg·hm-2 treatment show the best performance, the highest yield was 3597kg·hm-2.(2) The coupling effect of irrigation and nitrogen fertilizer on the photosynthesis characteristics and soil water use of the oil sunflower in a drip-irrigated multiple cropping system was very significant. The Pn and Tr showed a trend of "rising-falling" in the whole growth period, and the peak appeared at the budding stage; the change trend of the WUE of the leaf is the change of the "rising-falling-rising" in the whole growth period; topsoil water consumption with oil sunflower growing period showed " rising-falling" variations, and the peak appeared at the flowering stage. Topsoil water consumption increased with irrigation water or fertilizer amount of nitrogen increased, soil water use efficiency decreased with the increase of the amount of irrigation, for soil water use, irrigation 3000m3·hm2、pure nitrogen 232kg·hm-2 treatment showed significant interaction effects.(3) Nitrogen accumulations of all organs of drop-irrigation multiple cropping oil sunflowers of different water-nitrogen combinations are centered by blades at earlier growth stage and by flower disc at late growth stage. Water-nitrogen combination has prominent or extremely prominent interaction effect on accumulation, distribution, transportation and absorption & utilization of nitrogen and production of oil sunflowers of all their organs at each growth stage. Appropriate water and nitrogen augment can promote effective nitrogen accumulation of each organ of oil flowers and transportation & utilization of nitrogen of oil sunflowers, thus realizing the goal of high production of oil sunflowers. Combining production of oil sunflowers and performance of the plants absorbing and transporting nitrogen, the best water-nitrogen combination of this experiment is irrigate with water of 3000m3·hm-2 and purely irrigate with nitrogen of 232kg·hm-2.(4) Water and nitrogen coupling significantly effect on the content 、 accumulation 、 relative accumulation of nitrate in soil and nitrogen balance. With the increase of nitrogen application, the content of nitrate in 0-80 cm soil and accumulation amount increased, the increase of nitrogen in 40-100 cm soil, and the degree of leaching loss increased; with the increase of irrigation water, the content of nitrate and the accumulation of 0-40 cm in soil decreased, and the 40-80 cm soil layer increased; after harvest, with the increase of irrigation water and nitrogen application, the relative accumulation of nitrate in 40-80 cm soil increased, and the 0-40 cm soil layer decreased. In irrigation 3000m3·hm2、pure nitrogen 232kg·hm-2 combination, the nitrogen in 40-100 cm soil relatively small increase, and the degree of leaching loss was lighter. The nitrogen uptake of oil sunflower in a drip-irrigated multiple cropping system through soil was most, in irrigation 3000m3·hm2、pure nitrogen 232kg·hm-2 combination.(5) Water and nitrogen coupling has a significant effect on the growth index and yield of oil sunflower in a drip-irrigated multiple cropping system. The design of water and nitrogen in this experiment is reasonable, and it provides a platform for the research of the optimal irrigation rate of high yield of oil sunflower. For irrigation-nitrogen-yield secondary regression curve fitting to get effect equation of yield of oil sunflower under water and nitrogen coupling. Only yield as the goal, when irrigation 3086.07m3·hm2, nitrogen 250.68kg·hm-2, the yield of oil sunflower is highest for 3605.83kg·hm-2. Conclusion: Water and nitrogen coupling significantly effect on the growth traits 、yield、 photosynthesis characteristics 、soil water use、nitrogen uptake and utilization. The best water-nitrogen combination of this experiment is irrigate with water of 3086.07m3·hm-2 and purely irrigate with nitrogen of 250.68kg·hm-2. Get effect equation of yield of oil sunflower under water and nitrogen coupling,and the yield of oil sunflower is highest for 3605.83kg·hm-2. It provides scientific basis for the development of scientific water and nitrogen control strategy of high yield and water saving and the of the popularization technology of oil sunflower drip irrigation in arid and semi arid area.