Soil C–CO₂ Emission as affected by mineral fertilization associated with organic matter in different soil textures

Soil C–CO₂ emission is an important indicator of the quality of biological processes, as it directly reflects microbial activity and the dynamics of organic matter. The objective of this study was to evaluate the effect of different mineral fertilizations associated with organic matter. The experiment was conducted under laboratory conditions in the municipality of Cáceres, Mato Grosso State, Brazil, using two soils, one with sandy texture and the other with medium texture. The experimental design was a randomized block design with six treatments, 1,140 kg ha⁻¹ of phosphorus pelletized with organic matter, 1,140 kg ha⁻¹ of phosphorus plus organic matter pellet, 833 kg ha⁻¹ of potassium pelletized with organic matter, 833 kg ha⁻¹ of potassium plus organic matter pellet, 500 kg ha⁻¹ of MAP and 410 kg ha⁻¹ of KCl, plus a control treatment and one blank per block, totaling four replications. The experimental period lasted 15 days, with C–CO₂ emission evaluations performed every 24 hours during the first three days and subsequently every 72 hours. Treatments combining pelletized mineral fertilization with organic matter promoted higher C–CO₂ emission and accumulation values in the sandy soil, with emphasis on the treatment using phosphorus pelletized with organic matter.