Biochemical parameters of an Oxisol submitted to high doses of gypsum in the coffee culture

The objective of this study was to determine the influence of increasing doses of agricultural gypsum on the quality of the soil biochemical attributes in coffee cultivation (Coffea arabica L.) by two climatic seasons in the Brazilian Cerrado. Soil samples were collected in two collections (dry and rainy season), at 0 – 10 cm depth of a Oxisol, submitted to doses 0 (GSA); 3.5 (G3.5); 7.0 (G7.0) and 14 (G14) Mg ha-1 of agricultural gypsum in the coffee planting line. The biochemical attributes evaluated were: total organic carbon (TOC); microbial biomass carbon (MBC); soil basal respiration (SBR); absolute enzymatic activities [Urease, acid phosphatase, hydrolysis of fluorescein diacetate (FDA)]. TOC showed no differences between treatments. The significant effect (p ≤ 0.05) of gypsum doses was observed for MBC and SBR, which were higher in the treatment with G7.0 application. The enzymatic activities of Phosphatase and the FDA showed no differences between treatments. On the other hand, the specific enzymatic activities by MBC were to describe the differences between the doses of gypsum applied, generally with greater activity in treatments G7.0 and G14. The accumulated coffee productivity was higher in G14 treatment. The results presented to confirm that the biochemical attributes of the soil are sensitive in the evaluation of changes in soil use and that the increase in gypsum does favor activity and microbial biomass.