Influence of N, P, K fertilization on yield and quality of Smooth Cayenne pineapple

Based on the 3414 fertilizer experiment design, a field experiment was conducted to study the effects of N, P and K fertilizers on yield and fruit quality of Smooth Cayenne pineapple, and optimum fertilizer rate. The results indicate that the applications of nitrogen (N), phosphorus (P2O5) and potassium (K2O) fertilizers separately improve the yields by 15.5, 4.8 and 12.6 t/ha, and the yield increasing rates are 16.8%, 4.5% and 13.1%. The net profits of the N, P2O5 and K2O applications are 34800, 11000 and 27600 Yuan/ha respectively and the agronomy efficiency (AE) of them are 39.3, 42.3 and 29.6 kg/kg respectively. The order of increasing yield, profit and fertilizer contribution rate (FCR) is in order: N＞K2O＞P2O5, and the relationship of AE of them is P2O5＞K2O＞N. Based on the P2 (100 kg/ha) K2 (500 kg/ha) fertilizer application, the vitamin C and total titratable acidity contents of the fruits are decreased with the increase of the nitrogen application, while the soluble sugar contents are increased. On the basis of the N2 (400 kg/ha) P2 (100 kg /ha) fertilizer application, the potassium application can increase vitamin C, titratable acidity and soluble sugar contents of the fruits. The application of phosphate fertilizer has little effects on the fruit quality. The results of the frequency analysis show that for the target yield over 105 t/ha and the confidence interval of 95%, the optimal fertilizer application rates of N, P2O5 and K2O, are 281.27436.48, 64.03121.69 and 428.59628.55 kg/ha respectively. The corresponding fertilizer ratio of N:P2O5:K2O is 1: 0.150.43: 0.982.23. This study provides a reference for farmers engaged in pineapple cultivation.