Evaluation of compost maturity and mineral enrichment quality through simple chemical parameters

The changes in different chemical parameters were studied at 30, 90 and 120 days of the composting process to evaluate the maturity and the quality of compost under aerobic decomposition of soybean, wheat, mustard and chickpea straw by mixing fresh COw dung in the ratio of I: I (w/w), mineral amendments, and with and without bioinoculum such as cellulose decomposer (Paecilomyces fusisporus, Aspergillus awamorie), P-solutilizing bacteria (Bacillus Polymyxa, Pseudomonas striata) and free living N2 fixer (Azotobacter chroococcum). The progressive decrease in total organic carbon, C/N ratio, water soluble carbohydrates, biodegradability index was observed irrespective of treatments in the progressive stages of decomposition. The total organic carbon decreased significantly and C/N ratio narrowed down to about 21.5 to 29.5 per cent by the application of bioinoculum. The water soluble carbohydrate decreased with days of decomposition process and maximum decrease was found during I20 days in bioinoculated materials which indicates that easily biodegradable carbon diminished much faster than resistant carbon materials. The significant increase in CEC was observed in all the materials under inoculated and it was maximum [110 cmol(p+)kg-ll under chickpea compost followed by wheat, soybean and mustard straw. The lignin content increased with maturation with concomitant decrease of cellulose giving rise to higher lignin/cellulose ratio. The CEC/TOC ratio increased to more than 3.5 up to 120 days of decomposition. The biodegradability index decreased with the days of maturation and funher decreased where the bioinocula were used. The application of bioinoculum significantly increased the available nutrient status such as NH4+-N, NO3--N, water soluble P, citrate soluble p and total p over uninoculilted Control. The enhanced use of bioinoculum in combination with chemical amendments accelerated the compost maturity and shortened the usual Period of composting.