Effect of organic waste compost and microbial activity on the growth of maize in the utisoils in Port Harcourt, Nigeria

Abstract

One of the major problems of agricultural soils in the coastal areas of the Niger Delta is the low organic matter content. Therefore, land application of composted organic material as a fertilizer source not only provides essential nutrients to plants, it also improves soil quality and effectively disposes soil wastes. In this study, poultry droppings, spent mushroom wastes, earthworm casts and soil samples were collected from the agriculture farm of the University and composted for 21 days. The composts were applied as nutrient supplements to maize crops at different concentrations of 3000, 9000, 18000 t/ha and control, to determine their effect on crop yield. The patterns of organic waste composting were compared among various combinations. The results obtained showed that organic waste compost application improved soil physical properties, increased nitrogen content, phosphorus, potassium and some micronutrients such as zinc, iron and copper. Vegetative growth parameters were better enhanced in maize stem length, girth, number of leaves and chlorophyll content while other nutrient combinations showed improved yields, especially Soil + spent mushroom wastes (SMW) + poultry droppings (PW) at 40 t/ha. Microorganisms involved in the breakdown of composts were isolated and characterized according to various biochemical reactions. They include Bacillus subtilis, Proteus vulgaris, Pseudomonas, Corynebacterium and Enterobacter species. Therefore, management of organic wastes through composting increases soil organic matter and other nutrients, and therefore had the added benefit of improving soil quality and thereby enhancing long term sustainability of agriculture. Their use also enhances microbial activities which enhances nutrient supply.

Keywords: Composts, organic wastes, inorganic fertilizers, microbial activities, soil, maize, nutrient content