Duality of Biochar and Organic Manure Co-Composting on Soil Heavy Metals and Enzymes Activity

Technological procedures for immobilizing agrochemical pollutants and activating soil enzymes that break down contaminants are still lacking due to industry’s ever-increasing number of new products to enhance agricultural production systems. Using animal manure as organic fertilizers in plant production is an affordable way to alleviate the production cost of inorganic fertilizers and improve crop yield and quality at an affordable price to limited-resource farmers. Microorganisms in animal manure secrete various extracellular hydrolyzing enzymes capable of breaking down organic matter and releasing C, N, and P for plant uptake. A field experiment was conducted to investigate the impact of combining biochar with animal manure on the activity of three enzymes involved in the N, C, and P cycles as a promising strategy for promoting soil health. The results have revealed variability among animal manure and biochar amendments in the activities of the three hydrolyzing enzymes. Biochar decreased the activity of urease and invertase in soil, indicating that some analytes in biochar act as enzyme inhibitors. The results also indicate that not all soil amendments promote soil enzymes activity, and this might be due to the various characteristics and composition of each animal manure.