Characterization of cattle manure-derived biochar and its synergistic effects with inorganic and organic fertilizers on soil properties, microbial community, and forage maize yield

Abstract

The impact of biochar on soil fertility and plant growth depends on its feedstock, physiochemical properties, and porous structure. However, cattle manure-derived biochar has been less used in practice, and its effectiveness on improving crop yield and the underlying mechanism are still unclear. This study characterized the properties and structures of biochar pyrolyzed from cattle manure from 200 °C to 600 °C. Subsequently, a field experiment was conducted to investigate the influence of biochar and its mixture with inorganic or organic fertilizer on soil properties, microbial community structure, and maize growth and yield. Based on a combined consideration of biochar yield, pore characteristics, specific surface area, and functional-group retention, 300 °C was selected as a suitable target pyrolysis temperature, with a relatively high biochar yield of 75.93%. The results revealed that reducing the inorganic fertilizer application rate by 50% and supplementing with biochar (FB50) resulted in a maize yield of 63.33 t·hm −2 , which was 9.83% higher than that under full inorganic fertilizer application (F; 57.67 t·hm −2 ), although the difference was not statistically significant, suggesting a sustainable approach to reducing chemical fertilizer use. Biochar likely improved maize growth by supporting keystone microbial taxa such as Chloroflexi , Proteobacteria , and Firmicutes , which are involved in nutrient cycling and enzymatic activities. Furthermore, co-applying biochar with organic fertilizer improved soil properties and microbial diversity, but did not improve maize production. Specifically, adding full-rate biochar (MB100) increased soil pH from 4.78 to 5.31 and soil organic carbon by 75.22% relative to manure alone (B). Overall, cattle manure-derived biochar offers a practical waste management solution, improving plant yields and soil health, while reducing chemical fertilizer reliance.