Evolution of phytotoxicity during the active phase of co-composting of chicken manure, tobacco powder and mushroom substrate

Abstract

This study systematically investigated the phytotoxicity of chicken manure co-composted with tobacco powder and mushroom substrate on seed germination during active phase of composting. All compost products met the sanitation requirements specified in the Chinese national standard; however, only the mushroom substrate compost satisfied the maturity standard. From day 28, the composting entered the end of active phase and the concentrations of K⁺, Zn²⁺, Na⁺, Cu²⁺ and Fe³⁺ decreased gradually. Redundancy analysis indicated that the germination index, catalase and peroxidase activities was positively correlated with K⁺, Zn²⁺, Na⁺, Cu²⁺, Fe³⁺ and NO₃^--N, and negatively correlated with NH₄⁺-N, Mg²⁺ and Ca²⁺, among which the most significant ions were Fe³⁺, Mg²⁺ and Zn²⁺ for all treatments. The malondialdehyde concentration of germinated seeds had adverse correlation with the above ions parameters.

Keywords: Agricultural waste; Composting; Ions; Phytotoxicity; Seed germination.