Effects Of Long-Term Phosphorus Application On Wheat-Maize Phosphorus Absorption And Soil Phosphorus Accumulation And Migration

North China is an important food production area in my country.Winter wheat-summer maize rotation is the main farming method in North China.The application of phosphate fertilizer during the rotation provides the necessary guarantee for high crop yields.Excessive application of phosphate fertilizer not only fails to increase the utilization rate of phosphate fertilizer,but also causes the risk of phosphorus accumulation in the soil.In order to explore the yield of winter wheat and summer maize under the condition of long-term phosphorus application,the law of phosphorus absorption,and the surplus and loss of soil phosphorus and the accumulation of phosphorus,this study was carried out in Qingyuan District,Baoding City,Hebei Province from 2011 to 2020.The experiment was carried out in winter wheat-summer maize rotation.The system is the research object.By setting four different phosphorus levels,the yield and phosphorus uptake of winter wheat and summer maize are determined,the phosphorus utilization rate and soil phosphorus deficit are calculated,and the phosphorus content of various forms of soil and soil adsorption characteristics are determined.Provide a theoretical basis for the rational use of phosphate fertilizers and the reduction of environmental risks.The main findings are as follows:(1)The 9-year winter wheat and summer maize yield results show that neither phosphorus application nor excessive phosphorus application will adversely affect the yield of winter wheat and summer maize.Proper application of phosphorus fertilizers can not only increase crop yields,but also reduce waste of resources.Environmental risks caused by excessive phosphorus application.Long-term non-application of phosphate fertilizer will lead to a decrease in the number of ears and grains per ear of winter wheat and summer maize,which in turn leads to a decline in crop yields.A suitable amount of phosphate fertilizer can increase the number of ears and grains per ear of winter wheat and summer maize,but exceeding the appropriate amount will cause winter wheat The number of ears of summer corn is significantly reduced,which in turn affects crop yields.Phosphorus fertilizer has little effect on the 1000-grain weight of winter wheat and summer corn.According to the results of the 9-year locating test,the phosphorus application rate for winter wheat in this area is 119 kg/hm2 and summer corn When the phosphorus content was 67 kg/hm2,the yields of winter wheat and summer maize reached the highest values,which were 7678.6 kg/hm2 and 10499.6 kg/hm2,respectively.(2)Long-term non-phosphorus application will reduce the dry matter accumulation and phosphorus content of winter wheat and summer maize plants,resulting in a decline in crop phosphorus absorption.Phosphorus application can significantly increase the dry matter accumulation and phosphorus content of winter wheat and summer maize plants,but After the optimum amount of phosphorus application is exceeded,the dry matter accumulation of crops will decrease,resulting in the crop phosphorus uptake with the increase of phosphorus application rate,which will first increase and then decrease.(3)Under the condition of long-term application of phosphorus,the utilization rate and cumulative utilization rate of phosphorus fertilizer in the summer maize season were higher than those in the winter wheat season;with the increase of planting years,the cumulative utilization rate of phosphorus fertilizer in the winter wheat season showed a downward trend.The cumulative utilization rate of phosphorus fertilizer shows an upward trend;the long-term non-application of phosphorus treatment soil apparent phosphorus deficit and accumulated phosphorus deficit are both in the state of phosphorus deficiency.With the increase of planting years,the annual soil phosphorus deficiency of the entire rotation system is maintained at 34.27 kg P2O5/hm2;the soil cumulative phosphorus surplus and deficit under the treatment of phosphorus application are all shown as phosphorus surplus,and the soil cumulative phosphorus surplus and loss have a very significant positive correlation with the cumulative years and the phosphorus application rate.(4)Long-term non-application of phosphorus will significantly reduce the content and accumulation of total phosphorus and available phosphorus in the soil.The content and accumulation of total phosphorus and available phosphorus decrease with the increase of soil depth.At this time,the content of the more active Ca2-P and Ca8-P and Al-P is low,mainly Ca10-P with weaker activity.Phosphorus treatment increases the content of total phosphorus and available phosphorus in the soil.The total phosphorus content in the 0-90cm soil profile is high in the middle and low in the middle.Phosphorus treatment increased the relative content of Ca2-P,Ca8-P and Al-P in inorganic phosphorus,and significantly decreased the relative content of Ca10-P.However,the application of phosphate fertilizer would also cause Ca10-in 60-90 cm soil.The relative content of P increased,while the content of Fe-P and O-P did not change much.(5)Long-term application of phosphorus can significantly reduce soil maximum phosphorus absorption(Qm),adsorption kinetic energy constant(K)and soil phosphorus maximum buffer capacity(MBC),and soil adsorption characteristic parameters are negatively correlated with phosphorus application;soil available phosphorus The content and phosphorus activation coefficient(PAC)are significantly negatively correlated with the maximum phosphorus uptake and the maximum buffering capacity of soil phosphorus,but are not significantly correlated with the adsorption kinetic energy constant.(6)The cumulative amount of soil phosphorus is directly proportional to the amount of phosphorus applied.The higher the amount of phosphate fertilizer is applied,the more phosphorus remains in the soil and the lower the phosphorus utilization rate.The phosphorus applied to the soil has 54.4%-65.4%conversion It is the total phosphorus in the 0-90 cm soil layer,4.0%-5.5%is converted into available phosphorus,and 16.4%-35.4%becomes unknown fate phosphorus.In short,a reasonable amount of phosphate fertilizer can increase the amount of phosphorus uptake by crops,while ensuring a high level of crop yield,it can also increase the utilization rate of phosphate fertilizer and reduce the accumulation of phosphorus in the soil.When the phosphorus application rate for winter wheat in this area is 105-150 kg/hm2 and the phosphorus application rate for summer maize is 60-90 kg/hm2,it can not only ensure high crop yields,but also reduce environmental risks caused by soil phosphorus accumulation.