Nutritive Characters and Fertilization Index of Nitrogen,Phosphor,Potassium for Major Vegetable Species in Fujian Ⅲ.The Optimal Amount and the Ratio of N,P and K for Application

With 3414 fertilizer experiment,the models of NPK fertilization for vegetables were established with quadratic polynomial in the optimal amount and the ratio of three elements.The results showed that the economic level of fertilizations were different in average for various kind of vegetables,such as: N(237113)kgm-2,P2O5(15069)kgm-2,K2O(289104)kgm-2 for leaf vegetables;N(237113)kgm-2,P2O5(15069)kgm-2,K2O(289104)kgm-2 for tuberous root;N(22163)kgm-2,P2O5(10741)kgm-2,K2O(217121)kgm-2 for melon and fruit;and N(26136)kgm-2,P2O5(83?59)kgm-2,K2O(243192)kgm-2 for onions,respectively.The differences in yield and nutritive characteristics of varieties resulted significant changes in amount of NPK fertilization.Among the optimal ratio,P2O5 and K2O was obviously higher in onions,melons and fruits than in leaf vegetables.The content of alkali-hydrolysable nitrogen,Olsen-P and available K in tested soil fitted in well with the NPK of recommended fertilization in exponential function relationship.It indicated that the established models are capable in prediction for the fertilization in virtual.