Short-Term Effects of Soil Tillage Systems on Crop Yield and Soil Physical and Chemical Properties in the Brazilian Pampa

The conversion of native grasslands into agricultural land in the Brazilian Pampa biome has intensified land-use change, increasing the need for effective soil management strategies due to potential impacts on crop yield and soil physical and chemical properties. This four-year study evaluated the effects of three soil tillage systems (no-tillage NT, minimum tillage MT, and conventional tillage CT) on grain yield and soil physical and chemical properties of an Ultisol in the Brazilian Pampa. Crop yields were monitored over four growing seasons (2015–2019) in a randomized block design with three replicates. Soil physical properties were assessed twice during the first growing season and once during the second and fourth growing seasons, whereas the chemical properties were analyzed in the second growing season. In the first growing season, CT and MT resulted in the highest corn yields and less compaction in the 0–5 cm layer, as indicated by lower soil density and higher total porosity and macroporosity. However, by the fourth growing season, NT yielded higher soybean yields (18 and 34% higher than CT and MT, respectively) and less compaction in the 0–5 cm layer. The soil’s chemical properties were not affected by the tillage systems in the short term. Although NT initially tended to lead to lower yields, after four years it offered higher gains in crop yield and improved soil physical properties in the surface layer, highlighting its importance for soil conservation and productivity in the Brazilian Pampa Biome.