Abstract:

Applying phosphorus was easily bounded by Ca+2 and Mg+2 and formed as insoluble phosphate in Ningxia Irrigation Area because the soil was classed as irrigation-silting soil and/or light sierozem, consequently the crop yield and P Use Effect were influenced greatly. In this paper, experiments were carried on different fields with high phosphorus level(available P, 42.8mg/kg) and low phosphorus level(available P, 6.55mg/kg) by applying phosphorus from 0 to 330kg/hm2 and divided into twelve treatments with 30 kg/hm2 interval. And the experiments were carried with three replication randomized block design. Results showed that phosphorus had a significant yield-increasing effect at low phosphorus field, and regression between P2O5 applying(X, kg/hm2) and yield(Y, kg/hm2) was set up as Y=4072.1+5.014x+0.1296x2-0.0003133x3, but at high phosphorus, the yield-increasing effect was not significant. So suggestions were put forward that Applying phosphorus from 0 to 240kg/hm2 had positive invest effect at low phosphorus level, within this paper, the P investment and produce effect were from 10 to 24 yuan/yuan(The price of wheat, 2.1yuan/kg, of P2O5, 8.61yuan/kg) and the max P investment and produce effect existed at P2O5 applying amount of 135 kg/hm2 . In addition, suggestions were also given to increase P use effect at middle-and-low-yield field and high-yield field according soil fertility in Ningxia Irrigation, such as combined tillage to increase phosphorus applying depth, applying phosphorus with organic manure, modulate PH with acidic fertilizer and increasing microorganism biological activity in soil.