Comparative Evaluation of Different Organic Fertilizer Effects on Soil Fertility, Leaf Chemical Composition and Growth Performance of Coconut (Cocos nucifera L.) Seedlings

Aims: Planting healthy coconut seedlings will reduce cost of establishment and increase total yield of coconut fruits for high economic value. Therefore, two experiments were carried out in 2010/2011 and 2011/2012 cropping seasons to evaluate the effects of different fertilizers on the soil fertility improvement, leaf chemical composition and growth performance of coconut (Cocos nucifera L) seedlings in the nursery.
Design: The experiment was laid out in a randomized complete block design and replicated three times
Place and Duration of Study: The experiment was carried out at Akure in the rainforest zone of Nigeria, West Africa
Methodology: Four organic fertilizers[ 6t/ha] treatments were used namely: goat manure, poultry manure, oil palm bunch ash and wood ash .A control treatment(no fertilizer, no manure) and inorganic fertilizer applied at 400kg /ha NPK 15-15-15 were also used.
Twenty Coconut seed nut were sown at a spacing of 0.25m by 0.25m between and within rows per seed bed. Adequate watering daily both morning and evening continued till the commencement of the rainy season in the following year.
At 10th week after planting, sown coconut seed nuts were recorded for sprouting and emergence. Also, at 12 weeks after planting, growth parameters (plant height, stem girth, leaf area and leaf population) of the coconut seedlings were measured and this continued every 2 weeks till 38 weeks after planting.
Results: The result showed significant (P=0.05) increases of plant height, stem girth, leaf area, leaf number, shoot weight, the contents of soil and leaf N, P, K Ca and Mg, pH and organic matter (0.M) compared to the control treatment. For growth parameters, poultry manure increased the plant height, stem girth, leaf area, leaf number and shoot weight of coconut seedlings by 24.8%, 14%, 18%, 16.6% and 37.5% respectively compared to wood ash treatment. When compared to NPK 15-15-15 fertilizer, it also increased the growth parameters as well as the concentration of N, K, Ca and Mg in leaf than NPK 15-15-15 treatment whereas inverse case was observed for P concentrations.
For soil chemical composition, Oil palm bunch ash and wood ash had the highest values of soil pH, K, Ca and Mg compared to goat and poultry manures. However, poultry manure had the highest values of soil N and P. with relative increase of K[96%], Ca[95%], Mg[25%], pH[87%] and 0.M[74%] contents compared to NPK fertilizer which has decreased soil 0.M and pH because of high K.Ca, K/Mg and P/Mg ratios.
Conclusion: Poultry manure applied at 6t/ha showed the highest performance, leaf and soil chemical composition and growth parameters of coconut seedling.