A Study On Physiological Basis And Optimized Agronomic Measures For Water-saving And High-yield Of Spring Wheat In Hetao Irrigation District

This experiment established on the basis of preliminary studies on the pattern of water-saving irrigation, through four factors five levels quadratic regression orthogonal design experiments to study the effect of the four agronomic measures that seeding density, nitrogen rate, phosphorus fertilizer, irrigation amount on plant morphological characteristics, leaf physiological indexes, physiological indices of groups and grain-filling characteristics, water and fertilizer use efficiency and yield traits of spring wheat, revealed the physiological mechanism of high water and nitrogen use efficiency and high-yielding of water-saving spring wheat; through established the quadratic polynomial regression mathematical model about that four agronomic practices with the economic yield and water and fertilizer use efficiency, quantitatively proposed the of agronomic measures optimized combination plan to realization the unification of water-saving and high-yielding Save fertilizer of spring wheat. The main conclusions are as followed:In the water-saving irrigation mode, augmented the population density, increased the nitrogen rate, phosphorus fertilizer and irrigation amount, the plant height and leaf area of above three leaves of spring wheat were expressed as increased trend, but no significant change in stem diameter; the plant height and stem diameter and leaf area of above three leaves in flowering period, taked on significant positive correlation with the yield. The SPAD and Fv/Fm values of flag leaf in flowering period were the highest, and then begin to decline until maturation period. The SPAD and Fv/Fm values of flag leaf of wheat in pustulation period decreased slowly to maintain high photosynthetic activity under reasonably planting density and suitable nitrogen application (phosphorus) and the amount of irrigation.Treatment under different agronomic practices, the leaf area index, photosynthetic potential and growth rate of population of spring wheat showed a single peak curve during the whole growth period, the peak value appeared in the period that from heading period to flowering stage. Dry matter accumulation showed S-shaped curve with the growth. In the water-saving irrigation mode, with the increased of planting density, nitrogen, phosphorus and irrigation amount, the leaf area index and photosynthetic potential and dry matter accumulation of spring wheat showed an increasing trend in the early growth stage; After flowering, the leaf area index and photosynthetic potential and dry matter accumulation and accumulation rate under the medium density, fertilization and irrigation treatments decreased relatively slow and high-value stabilization period maintained longer. The leaf area index and photosynthetic potential and dry matter accumulation and accumulation rate in pustulation period with the economic yield showed a significant positive correlation. Under water-saving conditions, nitrogen fertilizer, phosphate levels, planting density and irrigation amount with the yield of spring wheat and water use efficiency (WUE) showed a parabolic trend. The planting density and phosphorus fertilizer four agronomic measures were the key factor to determined the height of yield of water-saving spring wheat and the WUE, increased the basic seedlings to improve the spike was the important way to obtain high yield.The nitrogen content and phosphorous content of whole-plant of wheat under different agronomic measures showed a decreasing trend with the growth process, and accumulation of nitrogen and phosphorus showed an S-shaped curve. With the increase of nitrogen fertilizer (phosphorus), the amount of absorbed nitrogen (phosphorus) of wheat plants were corresponding increase, nitrogen (phosphorus) prime apparent utilization efficiency agriculture use and nitrogen use efficiency (P) fertilizers partial productivity presented downtrend. Nitrogen (P) rate and nitrogen (phosphorus) prime utilization efficiency showed a significant negative correlation.Regression analysis showed that the economic yield, water use efficiency, nitrogen use efficiency and phosphorus use efficiency of wheat in water saving cultivation with the four main agronomic measures that nitrogen rate, phosphorus fertilizer, planting density, and irrigation amount conformed to the quadratic polynomial regression mathematical model all. By optimizing analytical model proposed the agronomic measures optimized combination plan to realized the unification that water-saving fertilizer-saving and high-yield of spring wheat in water saving cultivation in Hetao irrigation district:the basic seedling number was6.785-7.069million plants per hectare, the amount of phosphorus(P2O5)was142.4-151.2kilos per hectare, nitrogen rate of jointing stage (pure N)was132.5-161.4kilos per hectare, the irrigation quota of jointing and heading stage was914.5-951.6cubic meters per hectare. According to this scheme to implement, economic yield of yield can run up to7500kilos per hectare, water use efificiency reached more than1.6kilogram per stere, The agronomic use efficiency of nitrogen and phosphorus outnumbered10kg/kg.