Influence on C–CO₂ emissions in clay-textured soil as a function of the use of biofertilizer produced from fish waste

Considering the extensive agricultural activity in Brazil, especially in the state of Mato Grosso, which stands out as the largest cultivated area for major crops and for livestock production over extensive pasturelands, there is a high demand for chemical fertilizers. In many cases, this demand is not fully met by the market, and the continuous and excessive use of these inputs may result in negative effects on soil quality. Therefore, it is essential to promote the development and use 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 conducted under controlled conditions using a completely randomized design, consisting of seven treatments with doses of 0, 0.5, 1, 2, 4, 8, and 16 L ha⁻¹, applied to a clay-textured soil from the Sinop region, Mato Grosso State, Brazil. The evaluations were carried out over a sixteen-day period, with eight sampling times. The results showed differences among treatments, with greater microbial activity observed at the highest dose of 16 L ha⁻¹ compared to the other treatments.