From paddy to different land uses - soil changes in Albaqualfs in the lowlands of southern Brazil

Abstract The different agricultural production systems used cause impacts on physical attributes and on the availability of soil nutrients. In the south of Brazil, alternatives have been investigated for the use of paddy soils such as beef cattle farming associated with the diversification of agricultural crops as well as their impacts in the dynamics of soil attributes with a view to greater sustainability of production systems in lowlands. Thus, the objective of this work was to evaluate changes in physical attributes, availability of nutrients and soil organic matter content in an Albaqualfs under systems: (BC) beef cattle, (R/BC) irrigated rice and beef cattle and (S/C/BC) soybeans, corn and beef cattle, with management systems BC and S/C/BC stablished on large-based ridges conducted under no-tillage in an Albaqualfs. Soil sampling was carried out in October 2018, with 4 replications in each management, in the layers from 0.00 to 0.05 m, 0.05 to 0.10 m and 0.10 to 0.20 m, in triplicate, for determination bulk density (Bd), particle size distribution, macroporosity (Ma), microporosity (Mi), total porosity (Tp), water retention curve (WRC), pH in water, phosphorus (P), potassium (K), aluminum (Al), calcium (Ca), magnesium (Mg) and soil organic matter (OM). The mean weighted diameter (MWD) of the aggregates decreased with increasing depth, being greater values obtained in BC, standing out for higher values of macroporosity and macroaggregates in the 0.00 to 0.05 m layer. For the chemical variables P and Al, higher values were found in the BC, in the 0.00 to 0.05 m layer. The OM contents were higher in this same management system, in the 0.10 to 0.20 m layer; however, it did not differ from the R/BC. In the 0.00 to 0.05 m layer, the S/C/BC showed higher Ca and Mg values than the other management systems.