Characterization of blood meal and vermicompost blended bio fertilizer: Chemical composition of output, microbial biomass and chemical composition of different sources of blood meal.

Abstract

This study characterized the chemical and microbial properties of vermicompost–blood meal biofertilizer blends under controlled laboratory conditions. It responds to the growing need for alternatives to synthetic fertilizers, which pose environmental and economic challenges in Zimbabwe, especially for smallholder farmers. The research employed a Completely Randomized Design (CRD) and analytical methods including ANOVA and microbial biomass assays to assess key parameters across different blending ratios. Four treatments were tested: Control (100% vermicompost), 1:3, 1:4 and 1:5, pig blood meal–vermicompost blends. Fermentation stabilized pH across all treatments, with values ranging from 9.05 to 9.12. Organic matter increased sharply from 1.50% in the control to 22.8% in the 1:3 blend, while the carbon-to-nitrogen ratio rose from 12.0 to 24.8. Available nitrogen peaked at 3.64% in the 1:3 blend, compared to 1.50% in the control, and available phosphorus reached 0.223% in the 1:4 blend. Microbial assessments revealed that total viable counts (TVC) dropped by 70% in the 1:3 blend versus the control (from 204,000 CFU/g to 62,000 CFU/g), with complete elimination of detectable molds. Analysis of blood meal sources showed cattle blood with the highest nitrogen content (12.04%), followed by pig (11.20%) and chicken (10.05%). These findings demonstrate that a 25:75 blood meal–vermicompost blend optimizes nutrient stabilization, enhances organic matter, and suppresses unwanted microbes, offering a scalable and sustainable alternative to chemical fertilizers for smallholder farmers. It calls for strategic blending of blood meal with vermicompost which can result in a nutrient-enriched, microbially stable, and ecologically sound alternative to chemical fertilizers, with direct implications for crop productivity and soil health management in organic and resource-limited farming systems.