The Effect Of Limited Irrigation And Phosphorus On Growth And Nutrient Uptake Of Winter Wheat

Water and nutrient deficiencies are two key factors of limiting the development of agriculture in the dry land. Nitrogen (N) and phosphorus (P) are essential nutrients for crop, and play important role on increasing yield and quality of dry land crops. There are close relations between nutrient uptake, transport and crop yield, quality and water and nutrient use efficiency of crops. The methods of field experiment, simulation experiment and analysis were used to study the effects of the different measures (i.e., mulching, fertilization and irrigation) to control the supply of water and nutrients on nutrient uptakes, accumulations and translocation of winter wheat; this research was mainly to study how water and phosphorus to influence crop yield, dry matter accumulation, the absorption of water and nutrients, and the distribution of soil moisture, ammonium P in profiles etc. The objectives were to understand the reasons for the decrease of crop yield and the accumulation of nitrate P in the soil with applying excessive N and P fertilizers. The main results were as follows:1. The result showed that irrigation and phosphorus can enhance biomass and yield components remarkably. The plant height increase with the increase of irrigation quantity, the effects of water on yield and 1000-grain weight reached a remarkable level and there are no remarkable differences in spike length, spike weight and kernel numbers per spike. Tillering number, spikes number, 1000-grain weight, yield and irrigation water use efficiency increase with the increase of phosphorus. Phosphorus fertilizer has no significant effect on plant height.2. Applying nitrogen and mulching mainly improve the activity of crop photosynthesis, resulting in the increase of short-time water use efficiency. Irrigation mainly accelerates transpiration rate of winter wheat, leading to the decrease of P/E. It is relationship of non-linear between transpiration and photosynthesis of Winter wheat, when it is a lower level, the photosynthetic rate increased and transpiration rate of winter wheat slowly increase, but increase to the certain extent after, the photosynthetic rate increase is not as transpiration.3. Along with infuse the increment of the amount of water; the humidity makes use of the efficiency to descend gradually. At the drought and the humidity lack condition under along with increment, the humidity makes use of the efficiency increment. Increase humidity to make use of the efficiency under condition at the normal water supply without the obvious variety. The yield of winter wheat changed among different phases with the increase of field water consumption caused by irrigation, and the key reason was the variety of WUE. We introduced the concept of marginal water use efficiency (MWUE) and elasticity of water production (EWP) and discussed three phases of yield and WUE: when ET was less t, it was the first phase where WUE increased and yield was low; when ET was less, it was the second phase where WUE descended and yield was higher. When ET exceeded, it was the third phase where WUE was low and MWUE was less than zero. In the third phase, increasing irrigation would not benefit yield. The partition of three phases offered an important basis for reasonable allocation of irrigation water resources.4. The amount and ratio of nutrient translocations from leaf to grains vary with the mulching, and the supply of water and nitrogen fertilizer, indicating that the different water-fertilizer control measures can regulate nutrient transport and distribution in plant. Irrigation and mulching significantly increase the recovery of nitrogen fertilizer, agronomic efficiency and nitrogen physiological efficiency. The effect of phosphorus and irrigation is more significant increase the yield. When it is low water conditions in the winter period and the jointing stage, nitrogen can promote winter wheat on the N, P absorption, but in the body of their little effect on the distribution, and water with phosphorus under the conditions of phosphorus in the jointing stage can not only promote winter wheat on the nutrient The absorption, but also in the promotion of its transportation and distribution. Low water treatment under the conditions of high phosphorus suppression of the winter wheat N, P absorption of nutrients, phosphorus and water with conditions, high phosphorus treatment has obvious role in promoting, that the only adequate water supply to the high volume of phosphorus should play some role. In wheat during the period of phosphorus in the soil with phosphorus volume increased, and in the wheat growing period in different consistency ups and downs.