Evaluation of tomato waste compost stability and maturity using CIELAB color indicator

Plant residues consist of biodegradable organic materials and minerals that are well suited for compost production. The main prerequisite for compost to be safely applied into the soil is a high degree of stability and maturity, and the physical manifestation of this includes high stable organic matter content, and a lack of phytotoxic compounds. Tomato plant residues enriched with 20% chicken manure were composted in three rotary drum bioreactors to produce tomato waste compost (TWC) as a final product. Several physio-chemical stability and maturity parameters were assessed for the TWC. In addition, CIELAB color space parameters were used to ensure the stability and maturity of TWC as an alternative, fast, and low-cost technique for evaluating stability and maturity indices of compost. The results indicated stabilization of organic matter transformations during the composting process to create TWC. During active and curing phases of composting, results of the color parameters were in accordance with the measured physio-chemical maturity parameters; and the changes in TWC colors during active and curing phases of composting indicated that the final compost product was stable, mature, and that color analysis provided a low-cost alternative analytical approach for assessing the suitability of compost as a soil conditioner.