Impact of fish waste-based biofertilizer on C–CO₂ emissions in a medium-textured soil.

Given the extensive agricultural activity in Brazil, particularly in the state of Mato Grosso, which stands out for it is large areas cultivated with annual crops and for livestock production over extensive pasturelands, there is a high demand for chemical fertilizers. However, this demand is not always fully met by the market, and the continuous and excessive use of these inputs may cause negative impacts on soil quality. In this context, it is essential to encourage the development and adoption of bioinputs as sustainable alternatives. Thus, the objective of this study was to evaluate the effects of a biofertilizer produced from fish processing residues on soil C–CO₂ emissions. The experiment was carried out under controlled conditions using a completely randomized design, with seven treatments corresponding to doses of 0, 0.5, 1, 2, 4, 8, and 16 L ha⁻¹, applied to a medium-textured soil from the Cáceres region, Mato Grosso State, Brazil. Evaluations were conducted over a sixteen-day period, comprising eight sampling times. The results showed significant differences among treatments, indicating that biofertilizer doses influenced soil C–CO₂ emissions.