Soil physical quality in the topsoil of integrated and non-integrated grazing systems in a Brazilian Ferralsol

Abstract

Integrated grazing systems are important to tackle pasture degradation and promote agricultural sustainability, contributing to sustainable development goals and to soil quality. This study aimed to assess physical indicators of soil quality in the topsoil of integrated and non-integrated grazing systems. The studied systems included continuous grazing (CONT), rotational grazing (ROT), integrated crop-livestock (ICL), integrated livestock-forest (ILF), integrated crop-livestock-forest (ICLF) and an adjacent area with native vegetation (NV). The agricultural systems were established by 2011 and the soil was sampled in 2019. Assessments included saturated soil hydraulic conductivity (Ksat), soil bulk density (BD), total porosity (TP), macroporosity (MA), microporosity (MI), soil resistance to penetration (RP), mean weight diameter of soil aggregates (MWD) and total organic carbon (TOC). Apart from MWD, the soil quality indicators were sensitive in differentiating the studied systems. NV accounted for the highest means for Ksat, TP, and MA, and the lowest means for BD, MI, RP and MWD. Ksat in ICLF and ILF was higher than the other grazing systems. The lowest means for TP and MA, and the highest TOC was found in ICLF. BD, TP, MA and RP, which were strongly correlated with each other, suggest a degree of soil compaction in all grazing systems, caused mainly by cattle trampling. BD, MI, RP and MWD did not differentiate between grazing systems, indicating a similar soil quality between integrated and non-integrated grazing systems, which might be related to time since the experiment establishment. Further research is required for integrated and non-integrated grazing systems, including assessments of long-term experiments and testing novel indicators of soil quality.