Enhancing soil microbial properties through balanced inputs of organic and inorganic amendments are key to sustainable soil and crop productivity. A laboratory incubation study was conducted to determine microbial respiration, population and nutrient (N and P) mineralization patterns in an Ultisol amended with sole Urea at 56 kg N ha−1 or Urea (at 0 or 28 kg N ha−1) combined with 5 t ha−1 organic amendment (poultry manure Enhancing soil microbial properties through balanced inputs of organic and inorganic amendments are key to sustainable soil and crop productivity. A laboratory incubation study was conducted to determine microbial respiration, population and nutrient (N and P) mineralization patterns in an Ultisol amended with sole Urea at 56 kg N ha−1 or Urea (at 0 or 28 kg N ha−1) combined with 5 t ha−1 organic amendment (poultry manure compost, biochar or their mixture). The treatments were arranged in a completely randomized design, replicated three times and incubated for a period of 12 weeks at 30 0C. Microbial respiration, and mineralized N and P were measured fortnightly, while the heterotrophic bacterial and fungal populations were determined at the 2nd, 6th and 12th weeks of the incubation. The results showed that microbial respiration, and mineralized N and P increased in response to the organic amendments. Being richer in most measured nutrient elements, poultry manure compost, followed by its combination with biochar fortified with and without inorganic N, had the highest values of the evolved CO2, and mineralized N and P. Further, addition of compost, biochar or their mixture with and without fertilizer N when compared with sole inorganic N or the control without any nutrient addition, significantly increased bacterial and fungal populations in the soil. It was concluded that, sole and complementary applications of biochar and compost improve microbial activity, and can be adopted for soil health enhancement.
Abdulrahman B. L. (Sat,) studied this question.