Optimizing Soil and Fertilizer Phosphorus Management According to the Yield Response and Phosphorus Use Efficiency of Sugarcane in Southern China

Abstract

The objective of this study was to determine the suitable range of available phosphorus (P) and fertilizer application rate in a sugarcane-growing region with red soil in southern China. Thirty-five monitoring sites were selected to investigate the soil available P in relation to crop yield, P-use efficiency (PUE) and soil total P under four different P rates. Compared with the no-P treatment, all three treatments involving fertilizer P presented sugarcane yields increased to varying extents, with an average increase of 17.6–25.8%. The yield-increasing effects and PUE in each P treatment decreased with increasing soil available P. The agronomic critical values of available P for sugarcane according to the linear-linear, linear-plateau and Mitscherlich models were 27.7, 41.5 and 17.0 mg kg−1, respectively. When the response of the yield-increasing effects of P fertilizer to soil available P and the agronomic critical values of the three models were combined, the linear-linear model exhibited the best fit. An observable change occurred in the available P response to total P. After the change point, the available P increased dramatically with increasing total P, possibly leading to decreased PUE or even triggering water pollution. Therefore, 28–50 mg kg−1 is the suggested range of suitable soil available P for the sugarcane-growing region. In addition, when the soil P budget and current relatively high level of available P are considered, applications of P fertilizer at 120 kg P2O5 ha−1 (1/2 the conventional P fertilizer rate) are recommended in this region.