Soil biological attributes in pastures of different ages in a crop‑livestock integrated system

Abstract

The objective of this work was to evaluate the effect of the pasture (Urochloa brizantha) component age on soil biological properties, in a crop-livestock integrated system. The experiment was carried out in a Brazilian savannah (Cerrado) area with 92 ha, divided into six pens of approximately 15 ha. Each pen represented a different stage of the pasture component: formation, P0; one year, P1; two years, P2; three years, P3; and final with 3.5 years, Pf. Samples were taken in the 0–10 cm soil depth. The soil biological parameters – microbial biomass carbon (MBC), microbial biomass respiration (C-CO₂), metabolic quotient (qCO₂), microbial quotient (q_mic), and total organic carbon (TOC) – were evaluated and compared among different stages of the pasture, and between an adjacent area under native Cerrado and another area under degraded pasture (PCD). The MBC, q_mic and TOC increased and qCO₂ reduced under the different pasture stages. Compared to PCD, the pasture stages had higher MBC, q_mic and TOC, and lower qCO₂. The crop-livestock integrated system improved soil microbiological parameters and immobilized carbon in the soil in comparison to the degraded pasture.