Effects of Fertilizers with Different Proportions of N,P and K on Citrus Fruit Cracking

[Objective] The aim was to explore fertilizers with different proportions of N, P and K on citrus fruit cracking and to seek best treatment in preventing fruit cracking. [Method] Compound fertilizers with different proportions of N, P and K were prepared, supplemented by leaf fertilizers with varying mineral elements. [Result] It is proved the treatment II containing spring fertilizers （N：P2O5：K2O=20：10：10）, summer fertilizers （N：P2O5：K2O=16：8：16）, and leaf fertilizers with calcium nitrate solu- tion （0.5%） achieved the best prevention effects of fruit cracking. In the meantime, N-to-K ratio and N-to-Ca ratio were proved of positive correlation with cracked fruits, and the higher the ratios, the higher the proportion of cracked fruits, vice versa. On other hand, Ca-to-K ratio was of negative correlation with cracked fruits, and the higher the ratio, the lower the proportion of cracked fruits. [Conclusion] In practical production, fertilization should be conducted as per soil moisture content, tree growth, and seasons, in a balanced and comprehensive way.