Comparative Evaluation of Neem Leaf (Azardiracta Indica L), Wood Ash and Modified Neem Leaf Extracts on the Soil Fertility, Growth and Yield of Garden Eggplant (Solanium melongena L.)

Abstract

The effectiveness of liquid extracts from neem leaf (NLE), wood ash [WAE] and their modified forms (modified neem leaf MNLE) as fertilizer sources for improving soil fertility, growth and yield of garden egg (Solanium melogena L.) was demonstrated. Six treatments were tested, namely neem leaf extract, wood ash extract (WAE), modified neem leaf extract, poultry manure, N P K 15-15-15 fertilizer (NPK) and control (no fertilizer or extract). Results indicated significant increases (P<0.05) in plant height, leaf area, leaf population, number of branches, fruit weight, fruit length, fruit diameter, soil N, P, K, Ca, and Mg, content, and soil acidity under different fertilizer extracts compared to the control treatment. NLE yielded increased plant height, leaf area and stem girth of garden egg by 19.8%, 21.5% and 5% respectively compared to wood ash treatment[WAE]. As compared to NPK, NLE also yielded increased plant height and stem girth, while, NPK yielded increased leaf area and number of branches compared to NLE. Plant height and leaf area increased by 15% and 11% respectively under NLE treatment as compared to poultry manure. For the yield parameters, modified NLE yielded increased garden egg fruit weight, fruit length and fruit diameter by 37.5%, 41.55% and 31.3% respectively as compared to WAE, and fruit weight, length and diameter by 42%, 24% and 12.5% respectively as compared to NPK. When compared to poultry manure, NLE yielded increased fruit weight, length and diameter by 27.7%, 17.6% and 15% respectively. For soil chemical composition, WAE resulted in the highest value of soil pH while the modified NLE yielded the highest values of soil Ca, Mg and O.M(Organic matter). NPK had the highest values of N, P and K but decreased soil pH, Ca, Mg and O.M (Organic matter)., Modified neem leaf extract increased soil pH, Ca, Mg and O.M by 24%, 96%, 96% and 74.4% compared to N P K 15-15-15 fertilizer. This is because NPK fertilizer had highest K/Ca, K/Mg and P/Mg ratio signifying nutrient imbalance which might disturb uptake of K, Ca, Mg and P in soils. Modified neem leaf extract applied at 1200L/ha gave the best results in the growth, yield performance of garden egg and soil fertility improvement. This is a result of its combined nutrient superiority over the sole application of neem leaf, WAEs and poultry manure.