Study On The Effectiveness Of Adding Exogenous Carbon To Soil Phosphorus

Phosphorus is one of the macronutrients necessary for life and one of the limiting factors of crop yield in agricultural production.However,due to the poor mobility of phosphorus in the soil,it is prone to adsorption and precipitation reactions,its distribution in the soil is extremely uneven,and its utilization rate in the agricultural system is low.How to tap the potential contribution of soil itself to crop phosphorus nutrition has become an obvious research direction under the background of the increasing shortage of phosphorus resources in the world and the rapid increase of environmental and food pressures.The role of soil microorganisms as decomposers in the ecological cycle promotes the material cycle,and carbon is the most basic element of life.Therefore,this study takes carbon as a starting point,through regulating carbon and phosphorus to influence soil microbial activities,accelerate the transformation of different forms of phosphorus in soil,in order to improve the availability of soil phosphorus.In this study,the effects of adding glucose on soil microbial biomass and available phosphorus were compared under different soil types and phosphorus levels by using low phosphorus and high phosphorus purple soils and high phosphorus fluvo-aquic soils as test soils.On this basis,maize and rapeseed were selected for pot experiments to explore the effects of adding glucose and starting phosphorus fertilizer on soil microbial biomass and available phosphorus.The effects of plant phosphorus nutrition and the changes of soil microbial biomass and available phosphorus pool under the soil-plant system were also studied by pot experiment.The effects of different green manure rhizodeposition carbon on soil phosphorus availability and maize growth were also studied.The main results are as follows:1)Under simulated culture,the addition of glucose increased the soil microbial activity,the cumulative amount of CO₂ released from the soil increased significantly,the phosphatase activity increased,and the microbial biomass phosphorus increased.For low-phosphorus purple soil,the content of CaCl₂-P with very low content but high activity has no significant change,but the addition of glucose reduces the content of Olsen-P,Enzyme-P and HCl in low-phosphorus purple soil,and increases the organic phosphorus and Citrate-P;The addition of glucose had no significant effect on the content of Olsen-P in high-purple purple soil.The addition of glucose reduced the contents of CaCl₂-P,Citrate-P,HCl-P and organic phosphorus in soil,increasing the content of Enzyme-P;adding grapes reduced the high-phosphorus tide.Soil Olsen-P,Enzyme-P,and CaCl₂-P,Citrate-P,HCl-P increased,and the organic phosphorus content increased significantly.?2?The effect of adding glucose on plant growth in low phosphorus and high phosphorus soils is different.In the low-phosphorus purple soil,the start-up of phosphate fertilizer can have a greater impact on the growth of corn and rapeseed.The biomass and above-ground phosphorus uptake of the start-up of phosphate fertilizer and corn are higher.The addition of glucose or the application of activated phosphate fertilizer in high-phosphorus purple soil can promote the absorption of phosphorus by corn or rape.Soil microbes in low-phosphorus purple soil are simultaneously restricted by carbon and phosphorus.The amount of microbial biomass phosphorus in soil is higher when glucose is added or phosphorus is applied.The soil microbes in the high-phosphorus purple soil received carbon limitation,and the phosphorus content in the soil treated with glucose was higher.The addition of glucose or the application of activated phosphate fertilizer in low-phosphorus purple soil significantly increased soil phosphatase activity and Enzyme-P content,and the contents of Citrate-P and HCl-P also increased.The high-phosphorus purple soil has a decreasing tendency of CaCl₂-P in the soil after planting rapeseed and corn,and Citrate-P is significantly increased in the growth soil of rapeseed,and also increased significantly in the growth soil of corn.Trends in Enzyme-P and HCl-P content in rapeseed and corn soils.?3?The effects of carbon deposition on the growth of maize under different green manure-maize rotations were significant.Whether or not phosphorus was applied,the carbon deposition in the roots of green manure increased the aboveground biomass and phosphorus uptake of the later waxy maize.the amount.In the green manure of 4,the promotion of corn growth was from ryegrass,broad bean,wheat and eucalyptus.The four green manures had little effect on Enzyme-P.The carbon deposition of green manure decreased the content of Olsen-P,organic phosphorus and Citrate-P in the soil without phosphorus application.The carbon deposition in the roots of green manure decreased the content of Olsen-P,organic phosphorus and microbial biomass phosphorus in addition to wheat.In addition,Citrate-P and HCl-P are mainly reduced.In short,different green manure root carbon input or addition of glucose can promote the growth of corn or rapeseed,and start the role of phosphate fertilizer in the low-phosphorus soil.