Change in phosphorus requirement with increasing grain yield for Chinese maize production

By understanding the relation between maize (Zea mays L.) grain yield and phosphorus (P) uptake requirements it is possible to reduce both cost and environmental impact of maize production. The goal of this study was to determine P uptake requirements and patterns of P accumulation, pre- and post-silking, at different maize grain yield levels. A database comprising measurements in 955 plots in 44 on-farm and research station experiments during the period 2000-2012 on the North China Plain was used for the analyses. The P requirement (Preq., the P content Mg−1 grain yield on the basis of 155 g kg−1 moisture content) increased significantly from 2.84 kg in the P < Opt. treatment to 3.44 kg in the P > Opt. treatment. In the Optimal P treatment, average Preq. values were 3.41, 3.15, 3.09, and 2.94 kg for grain yields ranging from <8.0, 8-10, 10-12, and >12.0 Mg ha−1, respectively. The decrease in Preq. values with increasing grain yield was mainly attributable to the increase in the harvest index from 0.47 to 0.53 and the decrease in grain P concentrations from 2.73 to 2.42 g kg−1. A larger proportion of the P was accumulated post-silking when grain yields were higher than 10 Mg ha−1 (48%) and 8-10 Mg ha−1 (44%) than when yields were less than 8 Mg ha−1 (35%). Using this knowledge of P uptake requirements should improve assessments of global P balance, and help optimize P management, especially in high-yielding maize system.