Sustainability of dairy farms through vermicomposting of cattle manure and corn silage residues

Abstract

This article analyzes the characteristics of the vermicomposting process and the reproduction of Eisenia andrei earthworms during the vermicomposting of corn silage residues (CSR) with increased proportions of cattle manure (CM) by 10%, 30%, 50%, 70%, and 90% (volume/volume, v/v) resulting in the treatments CM10, CM30, CM50, CM70, and CM90. Physical, chemical, and biological parameters such as density, particle size, mass reduction, nitrogen, electrical conductivity, pH, number of earthworms, and cocoons were evaluated by using multivariate statistical analysis. The final densities after the vermicomposting increased 1, 25, 88, 142, and 178% in the treatments CM90, CM70, CM50, CM30, and CM10, respectively. The increasing proportions of CSR improved biodegradability, mass reduction, n and carbon/nitrogen ratio (C/N). The dry mass reduction in the vermicompost ranged from 50.6 67.6% and it was higher than 62% in the treatments with more than 50% of CSR. The treatment CM50 also resulted in the maximum increase in the nitrogen content. Higher proportions of CM increased pH, reduced electric conductivity (EC), and improved the reproduction of earthworms. Treatments CM90 and CM70 resulted in the highest increase in the number of earthworms, from 20 to 613 and 696, respectively. Thus, treatments with 50% of CM and 50% of CSR are recommended for the production of vermicompost and earthworms as by-products. The combination of favorable agronomic characteristics to the vermicompost and an attractive reproduction rate of earthworms is key-factor to improving biowaste sustainability in milk-producing units.