Establishing P fertilization recommendation index of different vegetables by STP with the "3414" field experiments in South China

The aim of this study was to establish phosphorus fertilization recommendation index of different vegetables (leafy, gourd and leguminous vegetables) by soil test P (Olsen-P and Bray 1-P) with the "3414" experiments of 121 sites during 2007-2010 in 30 counties of Guangdong Province, China. The results showed that relationship between vegetable relative yield and soil test P was linear with plateau and logarithmic equation model. The optimal amount of P fertilizer was established with soil test P by logarithmic equation mathematical models. The soil P content was calculated by the relative yield of 50, 75, 90 and 95%, to obtain the soil P abundance and deficiency indicators. Taking plentiful-lack of soil-test P as an index, soil Olsen-P and Bray 1-P were classified into five classes corresponding to relative yield of 50, 75, 90 and 95%. This study shows P fertilizer recommended rates were rendered by the models of soil test P with Olsen-P and Bray 1-P for "3414" field experiments for three vegetables.