Agro-environmental assessment of recycling abattoir blood meal powder as an organic fertilizer using soil quality index and hazard quotient

Purpose This study assessed the fertilizing potential and environmental impacts of recycling the blood meal powder (BMP) produced in the abattoir as an organic fertilizer in agriculture. Method In this study, a 70-day laboratory incubation experiment was conducted using a clayey calcareous soil to study the effects of adding abattoir BMP at three rates (1.5, 3.0, and 6.0 ton ha-1). At the end of the incubation period, the pH value, total C and N, inorganic N, and availability of macro-and micronutrient minerals (P, K, Cu, Fe, Mn, Ni, and Zn) were measured. Soil basal respiration, substrate-induced respiration, the abundance of cul-turable bacteria, fungi, and azotobacter, and dehydrogenase, alkaline and acid phosphomonoesterase, cellulase, invertase, protease, and urease enzymes activities were also determined as biochemical indicators of soil fertility. Results The results showed that the BMP has potential as fertilizer because it increased C, N, P, and Zn as compared to the control soil. Furthermore, the abundance of culturable microorganisms and dehydrogenase activity increased in the amended soil, whereas the other soil enzyme activities and basal respiration did not show an increase. The calculation of the Hazard Quotient (HQ) and the soil quality index (SQI) indicated that 3.0-ton BMP ha-1 is an appropriate treatment to improve soil quality without environmental hazards. Conclusion The results indicate that abattoir BMP application increased the fertility status of calcareous soil without environmental threats.