Abstract:In order to understand the effects of water—nitrogen coupling on nitrogen accumulation, transportation and distribution, absorption and utilization, and dynamics of nitrate accumulation in soil of dripirrigation multiple cropping oil sunflower in Shihezi area in the northern Sinkiang, based on field experiment, and combined with laboratory experiment, local early maturing variety “new No.5 hybrid oil sunflower” was taken as test materials, and a threelevel complete treatment plot experiment of two factors of water and nitrogen under drip irrigation was conducted. Results showed that nitrogen accumulations of all organs of dripirrigation multiple cropping oil sunflowers of different water—nitrogen combinations were centered by blades at earlier growth stage and by flower disc at late growth stage. Water—nitrogen combination had prominent (p<0.05) or extremely prominent (p<0.01) interaction effect on accumulation, distribution, transportation, absorption and utilization of nitrogen and production of oil sunflowers of all their organs at each growth stage. Appropriate water and nitrogen augment (pure nitrogen amount no more than 232kg/hm2, irrigation amount no more than 3000m3/hm2) can promote effective nitrogen accumulation of each organ of oil flowers and transportation and utilization of nitrogen of oil sunflowers, thus the goal of high production of oil sunflowers was realized. Water and nitrogen coupling significantly affected the nitrate accumulation in soil. With the increase of nitrogen application, the accumulation amount of nitrate in 0～80cm soil layer was increased; with the increase of irrigation water, the nitrate accumulation of 0～40cm soil layer was decreased, and that of 40～80cm soil layer was increased; after harvest, with the increase of irrigation water and nitrogen application, the relative accumulation of nitrate in 40～80cm soil layer was increased, and that of 0～40cm soil layer was decreased. Combining production of oil sunflowers and performance of plants absorbing and transporting nitrogen, the best nitrogen increase in faceplate was 2.16g/plant and yield was 3597.11kg/hm2，the best water—nitrogen combination of this experiment was irrigated with water of 3000m3/hm2 and irrigation with pure nitrogen of 232kg/hm2.
