COMPOSTING OF TANNERY WASTE WITH SAWDUST FOR PRODUCTION OF ORGANIC MANURE

Abstract

ABSTRACT The utilisation of tannery waste (TW) in combination with sawdust (SD) as compost manure for agricultural use was studied. The two wastes samples were collected and mixed in the ratios (TW/SD) 1:1, 1:5, 5:1, 1:10 and 10:1, respectively. Composting bin was used during the process. The composting was done for 6 weeks under aerobic condition with frequent turning for proper aeration. Microbiological and physicochemical parameters of the samples (tannery waste and sawdust), experimental soil (SL), as well as the finished compost were determined using standard methods. The microorganisms isolated from the wastes (TW, SD and SL) were species of Bacillus, Escherichia, Micrococcus, Proteus, Pseudomonas, Streptococcus, Staphylococcus (bacteria) Aspergillus, Mucor, Tricophyton, Rhizopus, Penicillium, Fusarium, Candida and Saccharomyces (fungi). The resultant compost was obtained 42 days after being composted; it was odourless, stable and had earthly smell. The pH of the matured compost ranged from 7.30 to 8.05 (moderately alkaline), total organic carbon (14.84% to 24.33%), carbon to nitrogen ratio ranged from 10.96 to 31.46, phosphorus content (2.55 to 3.48%), potassium content (0.961 to 2.912%) and heavy metals such as (Cr, Pb, Cd, Zn, Hg, Fe, Mg) were within the permissible limits for matured quality compost. The germination index (emergence) was significantly high (p<0.05) in all treatments including the control. The resultant compost was used to assess the growth parameters (leaves, height and stem girth) and yield performances of maize plants. Maize plants treated with compost (TW/SD 1:1), supported good growth pattern as well as seed formation, while maize plants treated with compost (TW/SD 1:10) had poorest response which resulted in stunted growth with smaller leaf sizes as well as narrowest stem girth. Compost (TW/SD 10:1) supported good growth pattern of the maize plants with significant increase in height, stem girth and leaf length (with extensive leaf sizes and greenish). This suggests that the nutrient content of the compost (TW/SD 10:1) was utilized by the plants for their growth. Height of maize treated with TW/SD 1:1 on maize was not significantly (p>0.05) different from Amazing organic fertilizer (commercial). The yield of maize was obtained 102 days after planting. The mean yield of maize raised with the compost TW/SD ranged from 0.4±0.05kg to 1.5±0.01kg. The highest yield of 1.5±0.01kg obtained with TW/SD 1:1 was significantly different (p<0.05) from TW/SD 10:1. The results obtained suggest that tannery waste/sawdust compost in the right combination can be applied for the improvement of soil organic matter and boost food production.