Effects Of Different Forms Of P Fertilizer And Its Supply Strategy On Soil P Availability And P Utilization Efficiency On Calcareous Soil

【Object】Phosphorus utilization ratio in calcareous soil is low, Studying the efficient P fertilizerapplication methods in calcareous soil under drip irrigation, and searching for the effects of different Psources and applications to The effectiveness of soil phosphorus, which are the important methods toimprove fertilizer use efficiency and crop P nutrition. Through the research of response of threefertilizer(DAP, liquid phosphoric acid, and polyphosphate) and two application methods to P mobility andeffectiveness in calcareous soils, And through its influence on corn p nutrition, designed to enhance theefficient utilization of phosphorus resources in Xinjiang oasis farmland and provide theoretical support, andinnovation phosphorus resources management in arid areas of Xinjiang and achieve high efficiency ofcrops which could provide technical assurance.【Method】1. Using a field experiment under drip irrigation, setting different phosphorus sources anddifferent application methods as the treatments to study the transformation, mobility mechanisms, effectivebiological effects and its efficient use of P under "a few times and one water, one fertilizer" fertigationmethod.2. Employed network chamber pot experiment to simulate Film Drip Irrigation, which to study thebiological effects of P fertilizer due to different P fertilizer sources and a variety of application methods.3. Using DGT(diffusive gradients in thin films) to study the fertilizer efficiency of different P sources andphosphate fertilizer application methods and diffusibility in different distances.4. Employed soil liquid extraction device to study soil P supply to plants.5. Using P classification method by Guppy to research the proportion and transformation of various formsof P content in Soil P pools and the response of it to plant P absorption, andto achieve a reasonable evaluation of calcareous soil P supplying capacity as purposes.【Results】1. The same results in the field experiment and net chamber pot experiment are that soilOlsen-P content and water soluble phosphorus content in all liquid fertilizer for top dressing treatment wassignificantly higher than that in basal application of solid manure-based fertilizer treatment. Potexperiment was found that polyphosphate fertilizer made maximum contribution rate of water-soluble P insoil Olsen-P and water soluble P content. Olsen-P content was42.1mg/kg and water-soluble phosphoruswas3.2mg/kg in polyphosphate treatment in the dressing corn maturity, which were the highest among alltreatments. The research of DGT technology showed that different ways of applying fertilizer had hugeimpact on P mobility in different spatial location. DGT concentration decreased from the outer layergradually to the point of fertilization in the horizontal direction, the highest concentrations of DGT occuredbetween0-2.5cm, and the concentration in the vertical direction decreased gradually.2. In drip irrigation, Guppy method of soil P grading found the order of percentage of various forms of P insoil was HCl-P> residue-P> NaOH-P> NaHCO3-P> Resin-P. Correlation coefficient between Resin-P, NaHCO3-P, NaOH-P, residue-P and HCl-P and plant P uptake were:0.6862,0.4888,0.4042,0.2963,0.0128.3. Under drip irrigation, Compared to60%of base fertilizer diammonium phosphate solid+40%topdressing treatment increased by25%, liquid fertilizer100%with drip irrigation increased corn ear weigh,grain weight and production significantly..4. Liquid phosphate fertilizer utilization over time is significantly higher than the water-based solid DAPapplied in field plot trials. Compared to60%of base fertilizer diammonium phosphate solid+40%topdressing treatment increased by24%, phosphate fertilizer utilization rate is up to40.6%.【Conclusion】1. The bioavailability of liquid P fertilizer in soil was better than solid phosphatefertilizer. There was a significant differences between various P fertilizer sources effectiveness, and thepolyphosphates was the best fertilizer.2. The bioavailability of topdressing P fertilizer in soil was better than the traditional way of basefacilities-based fertilizer. In calcareous soil, based on corn absorption characteristics of P nutrition, throughintegration times with water drops applied phosphorus could improve the efficient use of nutrients and cornyield significantly.3. Compared with base facilities-based solid fertilizer, topdressing liquid fertilizer was more activated soilphosphorus library and reduced soil phosphorus ratio of the proportion of invalid state forms of phosphorus.Guppy P graded proved resin-P, NaHCO3-P, NaOH-P were high effective P component and residue-P andHCl-P was likely to slow-phosphorus or phosphorus component which was invalid. DGT technology couldmeasure the spatial distribution of soil P and effectiveness quickly, continuous and multi-point. Soil liquidextraction techniques could not only keep the true distribution of the natural traits of undisturbed soil andnutrients, and also could provide soil nutrient which accurate decisions needed.