Abstract
Application of anaerobic digestates (ADg(s)) from organic wastes as bio-fertilizer in agricultural field is economically viable and environmentally sustainable alternative. The study aimed to utilize ADg(s) (25, 50, 75 and 100% w/w) from the organic proportion of flower-waste (FW), sewage-sludge (SS) and municipal solid wastes (OFMSW) as soil amendment to investigate soil nutrient status and growth performances of tomato (Solanum lycopersicum var. Kashi Aman). Organic carbon, nitrogen, phosphorous, exchangeable Na, K and Ca ions, and enzymatic activities were increased with increase in ADg(s) amendment in soil with relatively higher increase under OFMSW amendment. Metal contents in the soil amended with ADg(s) were in the order, Fe > Zn > Mn > Cu > Ni > Cr > Cd and their contents increased with increasing OFMSW, SS and FW. Plant biomass and fruit-yield were higher under all ADg(s) amendments compared to the control, with maximum yield under 100% SS. Contents of Fe, Zn, Mn, Cu, Cr and Pb in the entire plant were positively correlated with the yield under all ADg(s) amendments. Based on translocation and bioconcentration factors, tomato was found to be efficient in accumulation of metals except Cd. Content of Ni, Mn, Cu, Zn and Cd in the fruit were though below FAO/WHO limit, but Fe, Cr and Pb contents were above the limit. Hence, utilization of ADg(s) from OFMSW, SS and FW as fertilizer although improved the soil fertility and tomato yield, but due to high contents of Fe, Cr and Pb in the fruit, cultivation of tomato is not suggested.