Effect of Compost Enrichment with Urea and Streptomyces on Physicochemical Factors of Compost

Nitrogen addition, particle size, and microbial treatment are important factors in mature compost production. Therefore, this study aimed to investigate some physical and chemical parameters and nutrient content in wheat straw compost enriched with urea and Streptomyces. The incubation experiment was performed in a time-based, completely randomized design. To evaluate the effect of compost enrichment with Streptomyces and urea on available micronutrient elements, humification index of compost (E4/E6 ratio), pH, EC, C/N, temperature, Changes in moisture, and ash weight the following treatments (1) wheat residue size at three levels (R0 (<1), R1 (1-2) and R2 (2-4 cm)), (2) three levels of Streptomyces inoculation (S0 (0), S1 (0.5) and S2 (5%)), and (3) three levels of urea (U0 (0), U1 (8.05) and U2 (16.1 g kg-1)) with three replications were applied. The parameters were measured at different times during 90 days of incubation. A rapid increase in temperature in enriched compost with urea and Streptomyces treatment occurred in a shorter time than the control treatment. The pH value in all treatments decreased during the first 20 days of incubation and then increased. The C: N ratio significantly decreased due to the composting process. The humification index also reduced in the treated and control composts after 90 days of incubation. In general, the enrichment of compost with urea or Streptomyces showed increased nutrient values. However, the compost treated with Streptomyces and urea exhibited the highest values of nutrients compared to others. Our results showed that co-application of our isolate and urea can be used in composting process and improve soil properties better than non-treated compost. However, large-scale composting to prove the potentiality of the treatment in enhancement of compost quality is necessary.