NPK FERTILIZER EFFECT ON SOIL PROPERTIES AND YIELD OF PINEAPPLE (Ananas comosus L. (Merr.) IN CALABAR, SOUTHERN AGRO-ECOLOGICAL ZONE OF CROSS RIVER STATE

Abstract

Field trial was carried out for two years to investigate the effect of NPK 15:15:15 rates on soil properties and yield of four varieties of pineapple in Calabar, southern agro-ecological zone of Cross River State, Nigeria. A 4 × 4 factorial combination of four fertilizer rates: 0 (F₀), 50 (F₁), 100 (F₂), and 150 (F₃) kg ha⁻¹ and four pineapple varieties—three exotic varieties: Smooth Cayenne (C₁), MD2 (C₂), Queen (C₃), and one local variety, Abacaxi (C₄)—were arranged in a Randomized Complete Block Design (RCBD) with three replications. The soil used for the experiment was sandy loam in texture and strongly acidic. The results showed that most of the chemical properties of the soil were not significantly (P>0.05) influenced by the treatments. However, total nitrogen, soil pH, exchangeable hydrogen, and base saturation were significantly (P<0.05) increased by the rates of application of NPK fertilizer. The highest yield among the four pineapple varieties was recorded in the Smooth Cayenne variety at 150 kg ha⁻¹ of NPK fertilizer with a yield of 96.23 t ha⁻¹, although it was not significantly higher than the Queen variety at the same fertilizer rate, which produced 92.50 t ha⁻¹. Therefore, the application of 150 kg ha⁻¹ of NPK 15:15:15 fertilizer with Smooth Cayenne variety is recommended for pineapple production in the southern agro-ecological zone of Nigeria.