Study of three fertilizers produced from farm waste

Biofertilizers produced from pig farm aerotank active sludge, poultry dung under aerobic conditions, and poultry dung under anaerobic conditions were studied. The effects of these technologies on the quality, nutrient content, and bacterial communities of the final products have been evaluated. It was shown that Bacillus species represented 20-35% of the viable heterotrophic microorganisms in the fertilizers. Biofertilizers and isolated microorganisms suppressed growth of phytopathogenic fungi Bipolaris sorokiniana, Fusarium culmorum, and Sclerotium bataticola by 27-100%. In field experiments, application of the biofertilizers significantly increased the yield of Galega orientalis Lam. by 68-200%. All biofertilizers not only promoted the growth and development of plants, but also reduced the plant damage by insect pests. The greatest effect was observed following the application of the fertilizer Bamil prepared from pig farm active sludge. The fertilizer had the highest values of total N (5%) and tryptophan (388 μg g−1, dry wt.), and the smallest C/N ratio (8.6). Generally, biofertilizers produced under aerobic conditions were more efficient than that obtained under anaerobic fermentation. This can be attributed to nutrient availability, high tryptophan and microorganism content.