Microbial stability of worm castings and sugarcane filter mud compost blended with biochar

Organic amendments such as worm castings and sugarcane filter mud compost can provide nutrient rich substrates for enhanced plant growth. Physico-chemical and microbial stability of these substrates might be enhanced with the addition of biochar. A series of experiments was carried out to determine the stability of microbe populations in both worm castings and sugarcane filter mud compost with the addition of biochar made from sugarcane bagasse. Storage studies up to 150 days were carried out with biochar/worm castings and biochar/sugarcane filter mud compost blends on a volume basis (100/0; 90/10; 75/25; 50/50; 25/75; 10/90; 0/100). Physico-chemical properties, such as micro and macro nutrient composition, pH, ash and carbon contents, amongst others were monitored throughout storage time as well as microbe counts. No major deleterious effects to the microbial population were found by adding biochar to either substrate, despite decreasing moisture levels for increased biochar additions. Biochar might be providing nutrients needed by microbes, as well as possibly bind bacterial waste products that would otherwise be toxic to the microbe population. Larger scale studies are warranted as well as longer storage time to optimize shelf stability