Atributos físico-hídricos do solo e efeito de boas práticas agrícolas em unidades de produção de tabaco na Região Sul do Brasil

Abstract

Brazil ranks as the second-largest tobacco producer in the world. Tobacco cultivation is closely linked to family farming and has a significant socioeconomic impact, with the southern region of the country being the main production hub. A considerable portion of the cultivated areas lacks a higher level of adoption of good agricultural conservation practices to restore and preserve soil quality. Therefore, this study aimed to diagnose the physical and hydric quality of the soil in tobacco-producing farms under different cultivation systems and assess the effectiveness of adopting good agricultural practices to improve soil and water conservation in southern Brazil. In the first chapter, 11 properties in southern Brazil were studied, with soil analyses conducted at two depths (0.0–0.1 m and 0.1–0.2 m) across three cultivation systems (Tobacco, Other System, and Native Forest), where the Native Forest area was used as a reference. The evaluated soil physical-hydric attributes included bulk density, porosity, macroporosity, microporosity, and available water capacity (AWC). The results showed that in certain properties, particularly those managed under conventional practices, the critical limits established in the literature were exceeded, while the values remained below those observed in the Native Forest system, which presented the most favorable conditions. For the Tobacco and Other System production models, a lower water retention capacity in the soil was identified, indicating an opportunity to increase the adoption of soil conservation practices. In the second chapter, a single farm was used as a case study to conduct a field-level comparison of soil conditions before and after the adoption of good agricultural practices. The same soil depths were analyzed, and the same physical-hydric attributes monitored in the previous chapter were evaluated. The interventions applied included soil acidity correction, the use of different cover crops (a seed mix and single oat cultivation), and the implementation of a contour terrace for runoff control. The results demonstrated an improvement in water retention and soil structure. These findings reflect a short-term assessment over a single agricultural cycle. It is believed that continued long-term monitoring will allow for the observation of more consistent effects of good agricultural practices on soil physical and hydric quality.