Maturity evaluation of composts for safe use in agriculture

Five composts prepared from wheat straw enriched with different organic amendments were characterized to evaluate their suitability as fertilizers. The parameters determined were pH, total organic carbon, nitrogen, phosphorus, potassium, humus, heavy metals and enzymatic activities. The physiological effect of these composts was also studied on seed germi nation. After three months of decomposition, vermicompost had the lowest C: N of 11.6 with highest N, F and humus content and germination index of 90%. It was followed by microbially enriched compost (C: N 16.6). On the basis of self heating test, vermicompost was assessed as the most stable compost, free from toxic compounds. Contrarily, three months of decomposition period was not enough for wheat straw compost to be fully mature as adjudged from germination index and some other closely related parameters.