EFFECT OF PHOSPHORUS LEVEL ON NITROGEN ACCUMULATION AND YIELD IN SOYBEAN

In this paper,the 15N labeling with sand culture was conducted to study effects of phosphorus level on nitrogen accumulation,nodule nitrogen fixation and yield of soybean plants.Results showed that nitrogen accumulation,fixation and yield of soybean plants all presented a single peak curve with improvement of phosphorus nutrition level,with the peak value of phosphorus concentration in nutrient solution of 31 mg/L.When phosphorus concentration of nutrient solution was 11 mg/L,no obvious promotion was found on the ratio of nodule nitrogen fixation when increasing phosphorus concentration again,However,when phosphorus concentration of nutrient solution was 21mg/L,increasing phosphorus concentration again had no obvious promotion on soybean plant nitrogen accumulation,nodule nitrogen fixation accumulation and yield,indicating that effect of phosphorus nutrition level on nitrogen fixation was lower than that on yield formation level.