EFFECT OF INORGANIC AND ORGANO-MINERAL FERTILIZERS ON SOIL PROPERTIES AND NUTRIENT COMPOSITION OF PEPPER (Capsicum spp.)

Screen house and field experiments were conducted in Abeokuta, south western Nigeria in 2006 and 2007 to determine the effects of different rates of inorganic and organo-mineral fertilizers (OMF) on soil chemical properties and nutrient composition of pepper. The effect of independent application of OMF at different rates and chemical fertilizer (CF) was investigated in the screen house. The experimental method was completely randomized design (CRD) with the following treatments: 0, 2, 4, 6, 8,10, 12, 14 t/ha organo-mineral fertilizer (OMF) and chemical fertilizer (CF) at the rate of 60 kg N, 19.8 kg P, 39.6 kg K/ha. Based on the results obtained from the screen house study, the following treatments arranged in a randomized complete block design (RCBD) were used on the field: 12 t/ha organo-mineral fertilizer (100 % OMF); chemical fertilizer at 60 kg N, 16.9 kg P, 39.6 kg K/ha (100 %CF), OMF + CF (50:50), OMF + CF (25:75), OMF + CF (75:25). Parameters evaluated in the screen house were: nitrogen, phosphorus, potassium, pH and organic carbon contents of post-planting soil as well as number of days to 50 % flowering, fruiting and ripening, yield and vitamin C content of pepper.In addition to the above, nitrogen, potassium and phosphorus contents of pepper fruit were also assessed on the field. In the screen house, application of 12 t/ha organo-mineral fertilizer increased the potassium and organic carbon contents of post planting soil to the maximum (0.03 cmol/kg and 15.8 g/kg respectively). It also enhanced the fruiting and ripening of pepper and increased the vitamin C content (48 days, 94 days and 8.78 mg/100g respectively). On the field, application of OMF + CF (75:25) increased the vitamin C in pepper in both years (7.20 and 2.60 mg/100g) as well as nitrogen content inpepper fruit (22.5 g/kg) in 2006. The concentration of phosphorus in pepper fruit in 2007 was highest (3.5 mg/kg) by the above fertilizer rate while OMF + CF (50:50) and 100 % CF increased the potassium content to 61 and 31.7 mg/kg in 2006 and 2007 respectively. Number of days to 50% pepperripening was significantly reduced to 120 by the application of OMF + CF (25:75) and OMF + CF (75:25) against 130 days in the control in 2007. Application of 100% OMF improved the phosphorus content of post planting soil in 2006 and 2007 (10.8 and 7.1 mg/kg respectively) while the highest pH (7.4) which is significantly higher than the control was observed on plots treated with the above fertilizer rate in 2006. Pepper could be grown with 100% OMF, OMF + CF (25:75), OMF + CF (75:25) orOMF + CF (50:50) for improved yield, growth, nutrient composition and improved soil qualit