Effect of Phosphorus Fertilization to P Uptake and Dry Matter Accumulation in Soybean with Different P Efficiencies

Phosphorus (P) is an essential element for plant growth and yield. Improving phosphorus use efficiency of crops could potentially reduce the application of chemical fertilizer and alleviate environmental damage. Soybean (Glycine max (L.) Merr.) is sensitive to phosphorus (P) in the whole life history. Soybean cultivars with different P efficiencies were used to study P uptake and dry matter accumulation under different P levels. Under low P conditions, the P contents of leaf in high P efficiency cultivars were greater than those in low P efficiency cultivars at the branching stage. The P accumulation in stems of high P efficiency cultivars and in leaves of low P efficiency cultivars increased with increasing P concentration at the branching stage. At the late podding stage, the P accumulation of seeds in high and low P efficiency cultivars were 22.5 and 26.0%, respectively; and at the mature stage were 69.8 and 74.2%, respectively. In average, the P accumulation in whole plants and each organ was improved by 24.4% in high P efficiency cultivars compared to low P efficiency cultivars. The biomass between high and low P efficiency cultivars were the same under extended P condition, while a significant difference was observed at late pod filling stage. At the pod setting stage, the biomass of high P efficiency cultivars were significant greater (17.4%) than those of low P efficiency cultivars under high P condition. Meanwhile, under optimum growth conditions, there was little difference of biomass between the two types of cultivars, however, the P agronomic efficiency and P harvest index were significant higher in high P efficiency cultivars than those in low P efficiency cultivars.