Abstract:

Two P fertilizer of varying solubility, namely, Wucun phosphate rock (WPR), monocalcium phosphate (MCP), were incubated with twelve flooded paddy soils to quantify factors affecting the dissolution and availability of PR, the twelve paddy soils were sampled from Jinhua, Zhejiang province. Results showed the amounts of WPR dissolution (?NaOH-P) was negatively correlated with soil pH (P<0.01), exchangeable calcium and soil silt content (P<0.05), positively correlated with soil clay content (P<0.05). Stepwise multiple regression indicated that KCl extractable pH was the soil property that most affected PR dissolution, soil pH and adsorption parameter K together accounted for 78% of the variation in PR dissolution. The increase of soil available P (ΔResin-P) after WPR application was positively correlated with soil Olsen-P (P<0.01). Percentage of ΔResin-P by ΔNaOH-P after WPR application was positively correlated with soil Olsen-P (P<0.01), negatively correlated with soil clay content and Xm (P<0.01). Stepwise multiple regression indicated that soil Olsen-P and Xm were the soil properties that mainly affected percentage of ΔResin-P by ΔNaOH-P after WPR application.