Effect of Inorganic N and P Fertilizers on Fruit Yield and Yield Components of Pineapple (Annanas comosus MERR L. Var. Smooth cayanne) at Jimma, Southwest Ethiopia

Abstract

Field experiment was conducted at Jimma Agricultural Research Center (JARC) for two consecutive growing seasons (2012-2014 and 2015-2017 as a ratoon crop). The objective of the study was to evaluate the effect of different rates of inorganic N and P fertilizers on pineapple (variety Smooth cayenne) for yield and quality traits. Four levels of N (0, 93.6, 108 and 281 kg ha-1) and four levels of P (0, 134.8, 269.6 and 404.4 kg P2O5 ha-1) were arranged in RCBD with three replications. Data on yield and quality traits were collected and subjected to data analysis. Results of the study revealed that, the highest fruit yield was obtained by the rate of application of 281 kg N ha-1 and 134.8 kg P2O5 ha-1. Application of nitrogen at a rate of 281 kg ha-1 significantly increased fruit yield of pineapple up to 20.19% than the control. Similarly, phosphorus application at a rate of 134.8 kg P2O5 ha-1 increased significantly fruit yield by 68.22%. For high yield and good quality of fruits, nitrogen should not be applied beyond 108 kg N ha-1 rate. Apply treatments beyond 108 kg N ha-1, the TSS content declined by 1.95%. The economic analysis also revealed that the highest net benefit of 61,600.0 Ethiopian Birr/ha (ETB/ha) with marginal rate of return of 237.0% was obtained by the application of 281 kg N ha-1. Likewise, the net benefit of 12,320 ETB/ha with marginal rate of return of 507.0% were obtained by the application of 134.8 kg P2O5 ha-1. Based on the above results, a combined application of 281 kg N ha-1 and 134.8 kg P2O5 ha-1 are optimum and economically better for pineapple production at Jimma and its vicinity.