Application of 80% of routine phosphorus rate to keep high yield and P efficiency of maize and P balance in soil

ObjectivesSoil Olsen P contents show an increasing trend in black soil in recent years. In order to provide theoretical basis for rational amount of applied photo investigate the response of maize yield, component factors, nutrient absorption and distribution, phosphorus use efficiency and the change of soil Olsen P to P fertilizer rates in black soil under field conditions.

MethodsA 3-year field experiment was conducted in Gongzhuling City, Jilin Province, where the initial soil Olsen P content was as high as 30.15 mg/kg. The change of maize yield and component factors, P absorption and distribution, P use efficiency, the apparent P balance and change of soil Olsen P were analyzed under the P₂O₅ application rate of 0, 60 and 75 kg/hm².

ResultsThe results showed that the application of phosphorus fertilizer increased the maize yields, in 2011 the yields in P60 and P75 treatments were significantly higher than in P0, but the yield gap between the P60 and P75 treatments decreased with years. More P was absorbed in P75 than in P60, but the proportion was decreased in the P75, which indicated that the P absorption was not transported to grain effectively and there was luxury absorption of P. The P use efficiency in P75 was higher than in P60, while the partial factor productivity of P was higher in P60 than in P75 in all three years, which indicated that the combined effect of basic soil nutrient and applied P was larger in the P60. From 2009 to 2011, the apparent P balance in P0 was in deficient state, while those in P60 and P75 were surplus. The change in soil Olsen P was positively linearly correlated with the P budget (P < 0.01), for every increment of 100 kg/km² of P surplus, the corresponding increase in soil Olsen P was 9.6 mg/kg.

ConclusionsIn the black soil with relatively high Olsen P content, application of 20% less of the routine amount of P rate (P₂O₅ 60 kg/hm²) will meet the demand for high yield, maintains the soil Olsen P content and effective supply ability of phosphorus, and increase the phosphorus utilization efficiency.