Effects of Phosphorus Application on Nitrogen Accumulation Sources and Yield of Peanut

Pot experiments and 15N tracer technique were carried out respectively to study the effects of different phosphorus application on soil nitrogen uptake,fertilizer nitrogen uptake,nitrogen fixation and their proportion and yield of peanut,and to explore the reasons,the research on which may provide a theoretical basis and technical guidance for peanut production in the scientific fertilizer application.The results showed that root dry matter weight and root activity of peanut were improved with the increase of phosphorus application.Root nodule number and nodule fresh weight increased with increasing phosphorus application.Nitrogen content of different organs and 15N abundance in peanut plant were improved along with the increase of phosphorus application.In addition,both nitrogen accumulation in different organs and 15N accumulation were increased with the increase in phosphorus application during peanut mature stage.The ratio of fertilizer nitrogen,soil nitrogen and atmospheric nitrogen absorbed by peanut was respectively between 11.34%-12.69%,33.95%-47.75%,40.90%-53.36%,which showed that increasing phosphate application reduced the proportion of soil uptake,and improved the absorption ratio of fertilizer nitrogen and atmospheric nitrogen.Use efficiency,soil residual rate and loss rate of nitrogen fertilizer of peanut were between 34.65%-47.53%,31.42%-36.00%,21.05%-29.35%,respectively.Nitrogen use efficiency was improved with increasing phosphorus application,while nitrogen soil residual rate and loss rate were decreased along with increasing phosphorus application.In summary,increasing phosphorus application of peanut improved root dry matter weight,root activity,root nodule number and root nodule fresh weight,and enhanced the uptake of fertilizer nitrogen and the fixation of atmospheric nitrogen by peanut plant,thereby,improved nitrogen content of peanut plant,and promoted plant growth and development,ultimately increased peanut production.