COMPARATIVE EFFECTS OF BREWERY WASTE-BASED COMPOSTS ON SOME SOIL CHEMICAL PROPERTIES AND YIELD OF AMARANTHUS CAUDATUS

Composting of brewery waste (spent grains) into organic fertilizers can serve the multipurpose of conversion of waste to useful material, reduction of air and soil pollution as well as the cost of waste disposal. The research was aimed at determining the effects of brewery waste-based composts on some physical and chemical properties of the soil and the yield of Amaranth (Amaranthuscaudatus). The experiment was conducted at the Organic Vegetable Garden for Teaching and Research, Department of Agronomy, University of Ibadan, Ibadan. Treatments used were 20 t/ha of spent grain (SG) + Poultry dropping (PD) (1:1 and 2:1; v/v), spent grain (SG) + cow dung (CD) (1:1 and 2:1; v/v), spent grain (SG) alone (100% SG) and control (un-amended soil). The experiment was laid out in a randomized complete block design (RCBD) with four replications. The data collected were subjected to analysis of variance and means separated using Fisher?s least significant difference (LSD). The spent grains plus poultry droppings performed better than the spent grains plus cow dung in the release of organic matter, P, N, K, Na and Ca into the soil after the first and residual planting. All the treatments reduced the exchangeable acidity when compared with the control. Soils treated with spent grains plus poultry droppings (1:1) gave the highest values of organic carbon of 33.0 and 31.0 g/kg) and nitrogen of 2.98 and 2.91 g/kg respectively after the main and residual trials. The highest yield values were obtained in the spent grains plus poultry droppings (1:1) and the least in the control (un-amended) in both in both first (treatment) and second (residual) planting. In conclusion, the use of brewery waste-based composts for soil amendment added value to the improvement of the soil nutrient status.