COMPARISON OF THE EFFECTS OF ORGANIC FERTILIZERS WITH INORGANIC FERTILIZERS ON THE GROWTH OF EIGHT MONTHS OLD COCONUT SEEDLINGS AND THE NUTRIENT AVAILABILITY AND SOIL MICROBIAL ACTIVITY OF SOILS

Abstract

The study was planned to find out the effect of different fertilizers on the growth of coconut seedlings, availability of some nutrients and soil microbial activities with the aim of developing a fertilizer mixture that supports the plant growth with simultaneous improvement of soil health. Eight months old coconut seedlings of CRIC 65 cultivar was planted in large pots and kept inside a green house. Six treatments: control (T1), inorganic fertilizer (T2), BioGold® (T3), cattle manure (T4), Kochchikadebiofertilizer (T5) and compost (T6) were selected. Biweekly measurements of growth parameters, soil chemical parameters: pH, electrical conductivity, levels of K, P, Mg, and soil microbial parameters: biomass carbon and CO2 evolution were taken. The experiment design was a Complete Randomized with three replicates. The data were analyzed by analysis of variance (ANOVA) using the MINITAB statistical package. No significant differences (P<0.05) were observed in growth parameters, soil pH and EC throughout the research period in any of the treatments. The highest P level and lowest K level were observed in inorganic treatment after a six months period. Cattle manure contributed a high level of Mg to the soil. And hence possible to recommend cattle manure as a  good source of Mg. Significantly improved microbial activity was observed in BioGold® and the compost treatments. This implies that organic fertilizers are more environmental friendly compared to inorganic fertilizers.

Keywords: inorganic fertilizers, organic fertilizers, biofertilizers, soil nutrients, microbial activity, coconut