Decomposition Characteristics Of Organic Materials And Its Effect On Phosphorus Composition

Phosphorus is an important nutrient for crop growth.Phosphorus in the soil is mostly in a poorly soluble or adsorbed state,and its crop utilization rate in the current season is only 10% to 25%.When phosphorus is applied to the soil,it is easy to form insoluble phosphate and is fixed by soil minerals.With the large-scale application of phosphate fertilizer,especially the long-term application of organic materials based on crop nitrogen demand,the accumulation of phosphorus in the soil will increase and the mobility will increase,resulting in waste of resources and certain environmental impact.In order to systematically evaluate the effect of organic materials on the availability of phosphorus in red soil,this study selected phosphorus-rich vegetable garden soil as the research object,through the indoor soil culture experiment,the determination of straw and biomass charcoal decomposition process,soil phosphorus composition analysis and soil phosphorus adsorption.-Desorption test,studied the effects of different organic materials application measures on soil phosphorus availability and soil phosphorus adsorption performance.The main findings are as follows:1)In the determination of the decomposition process of straw and biomass charcoal,the first-order kinetic equation Pt=P0e-kt was used to fit the changes of the quality of straw and biomass carbon and the content of phosphorus in the culture,and the rot of straw was found.The rate of solution is much larger than that of rice husk biomass charcoal,and the decomposing rate of sage of sage is greater than that of rape stalk.The release rate of phosphorus in the decomposing process of rice husk biomass was similar to that of Chinese milk vetch,which was much larger than the release rate of phosphorus during the decomposing process of rape straw.2)The results of Hedley-P classification test showed that the addition of different phosphorus materials could significantly increase the content of inorganic phosphorus in soil(P<0.05).The effect of adding organic materials to enhance inorganic phosphorus in soil was significantly better than that of inorganic phosphorus.The effect was added(P<0.05),among which the effect of adding Ziyunying was the best,and the addition effect of the amount of phosphorus in rapeseed straw was the worst,while the effect of adding rice husk biomass carbon was the middle.The addition of exogenous phosphorus did not significantly increase the content of organic phosphorus in the soil,but significantly increased the content of Residual-P in the soil(P<0.05).The addition of organic materials to Residual-P was greater than that of equivalent phosphorus.The addition of inorganic phosphate fertilizer;among them,the addition of rice husk biomass carbon treatment has the most obvious effect on the promotion of Residual-P.3)The results of isothermal adsorption test show that the addition of Chinese milkvetch and rape straw can increase the soil phosphorus adsorption capacity,and the addition of organic materials can significantly increase the buffer capacity of exogenous phosphorus in the soil,and the best effect of adding Ziyunying straw.The rapeseed straw is second.However,the addition of organic materials of Chinese milk vetch and rape straw inhibited the desorption of soil phosphorus.