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

Abstract

The study was conducted at Gojeb Horizan plantation farm of South Ethiopia, for two cropping seasons (20122014 and 2015–2017 as a ratoon crop). The aim of the study was to determine the appropriate inorganic NP fertilizer amount required for high yield and quality of pineapple (variety Smooth cayenne) for production. 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) weresourced from Urea and DAP arranged in RCBD with three replications. Different yield, quality and yield related traits collected and subjected to data analysis. The result revealed that, the highest fruit yield obtained from application rate of 281 kg N ha-1 and 134.8 kg P2O5 ha-1. The rate of application of nitrogen of 281 kg ha-1 significantly increased the fresh fruit yield of pineapple up to 26.86% than the control. Likewise, application of phosphorus rate of 134.8 kg P2O5 ha-1 increased the fresh fruit yield of pineapple by 8.93% than the control. Similarly, the quality (TSS content) of pineapple significantly decreased when the applied nitrogen beyond 93.6 kg N ha-1 rate. Apply treatments beyond 93.6 kg N ha-1, similarly, the quality (TSS content) declined by 5.67%. The economic analysis also revealed that the highest net benefit of 18305.0 Ethiopian Birr/ha (ETB/ha) with marginal rate of return of 705.4% was obtained by the application of 281 kg N ha−1. Likewise, the net benefit of 131774.0 ETB/ha with marginal rate of return of 5431.74% 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 Gojeb plantation and its surroundings.