Effect of microbial enrichment on nutrient dynamics and microbial population of different organic composts

The increasing demand for sustainable agricultural practices has emphasised the importance of organic nutrient sources for maintaining soil health and productivity. Organic manures and composts play a vital role in improving soil physical, chemical and biological properties while supplying essential plant nutrients. However, the nutrient availability from organic composts largely depends on their degree of decomposition, carbon-to-nutrient ratios and microbial activity during composting. This study evaluated the effect of microbial enrichment on nutrient composition, microbial population and maturity indices of different organic composts. Four composts, namely urban compost (UC), press mud compost (PMC), poultry manure (PM) and vermicompost (VC), were subjected to enrichment using a microbial consortium along with a biocontrol agent during October 2023 at the Research Farm, Department of Soil Science, Mahatma Phule Krishi Vidyapeeth (MPKV), Rahuri, Maharashtra, India. The composts were inoculated with a bacterial consortia and Trichoderma spp. at 0.2 % (w/w) and incubated for 30 days under controlled moisture conditions. Samples were collected at 15 and 30 days to assess physico-chemical, nutrient and biological properties. Results indicated a gradual reduction in pH, electrical conductivity, total organic carbon, C : N ratio and C : P ratio during enrichment, reflecting accelerated decomposition and compost stabilisation. Significant increases in total nitrogen, phosphorus, potassium and microbial population were observed at 30 days of enrichment. Paired t-test analysis confirmed statistically significant improvement in nutrient content across all composts after enrichment. Among the composts, PM and VC exhibited superior nutrient enrichment and microbial activity. The study concludes that microbial enrichment effectively enhances compost quality and promotes the production of nutrient-rich organic amendments suitable for sustainable agriculture.