Abstract:Several P efficient and inefficient soybean cultivars were employed to investigate P nutrition characters, the optimal P application amounts and their economic benefits in the soils with three different fertilities in spring and summer seasons, respectively. The results show that soil P availability is an important limiting factor for soybean production in acid red soils, and biomasses, P uptakes and yields of the tested soybean germplasms are in the order of high > medium > low P soils. Soybean yields in low P soils are significantly affected by the phosphorus application, while much less in medium P soils and even negatively in high P soils. Furthermore, excess P fertilization could result in a ‘luxury absorption’. There are significantly genotypic variations on P nutrition characters of soybeans. Therefore, different P fertilizations should be employed to different soybean germplasms. Slight P application in low P soils, no P application in medium, and high P soils could meet the demand for the growth of the four new P efficient soybean germplasms. The results from economic analysis indicate that net incomes of P efficient soybean cultivars are much higher than those of local and control cultivars.