BIOINDICATORS OF SOIL QUALITY CULTIVATED WITH SOYBEAN UNDER ORGANIC MANAGEMENT

Organic agriculture is considered an option for sustainable development, as it enables the production of good quality food and contributes to the preservation of the environment, respecting biodiversity and the biological activities of the soil. Associated with this, soil bioindicators govern soil quality in different production systems, with the activity of the enzymes arylsulfatase and β-glucosidase being sensitive indicators of changes in agricultural management. The objective of this research was to evaluate the organic production system, based on the use of bioinputs, regarding the biological quality of the soil cultivated with soybeans in Southwest Goiás. The study was conducted at Fazenda Panorama, in the municipality of Santa Helena de Goiás, Goiás, Brazil. The evaluations were carried out in five areas under different land use and management systems, namely, organic system 1 (OS1 - soybean in succession to brachiaria) and organic system 2 (OS2 - soybean in succession to fallow), fallow, consolidated pasture (CP- Panicum maximum cv Tanzânia) and native vegetation (NV). The soil quality bioindicators were evaluated in the 0 to 10 cm layer, basal soil respiration (BSR), arylsulfatase enzymes, β-glucosidase, total organic carbon soil (TOC), clay content, and from this information the soil biological quality index (SQI-Bio) was determined. The area under CP showed lower microbial activity corresponding to 0.58 mg C-CO₂ kg dry soil^-1 h^-1 of BSR, while higher values ​​were found in the OS1 area with 1.26 C-CO₂ kg dry soil^-1 h^-1. This increase in BSR is probably due to a greater sensitivity of the soil biota in these management systems. The greater release of CO₂ is generally associated with greater biological activity, which, in turn, is directly related to the amount of labile carbon in the soil, despite not showing differences in TOC between the cultivation areas. The activity of arylsulfatase varied for the cultivated areas, being similar to NV only OS1 and fallow, which presented brachiaria in the crop rotation, reinforcing a distinct biological functioning of the soil in this rotation system, which reflects in a quality index (SQI-Bio) considered high for the OS1, fallow and NV areas. Confirming the ability of brachiaria to keep the soil biologically more active and healthy in the conditions of the Cerrado, as well as the sensitivity of the arylsulfatase enzyme in detecting changes in organic agricultural cultivation systems. This research is aligned with sustainable development goals 2 (Zero Hunger and Sustainable Agriculture) and 12 (Responsible Consumption and Production).