Spatial Variability and Correlation between Soil Physical Properties under No-Tillage with and without Agricultural Terraces

Abstract

The terracing is important for erosion processes control in agricultural areas. However, agricultural terraces are being removed from the production areas under no-tillage systems. There are still uncertainties about the terracing effects on the soil saturated hydraulic conductivity (Ks) and macroporosity (Macro), which represent the functionality of the system. We aimed to evaluate the magnitude and spatial distribution of Ks and Macro and the correlation between these soil properties in two paired megaplots, of 1.923 ha, one with terraces (T) and another without terraces (WT). Ks and Macro were determined at 0.00–0.10 m, 0.10–0.20 m, 0.20–0.30 m, and 0.30–0.40 m soil layers and submitted to descriptive statistical, geostatistics, and Spearman correlation analysis. Ks was highest in the 0.00–0.20 m and lowest in the 0.20–0.40 m layers in T. In WT, Ks was highest in the 0.00–0.10 m and lowest in the 0.10–0.40 m layers. However, the Macro was highest in the 0.00–0.10 m and lowest in the 0.10–0.40 m layers in both megaplots. Ks and Macro had a positive correlation in both megaplots. The spatial distribution of Ks and Macro had a positive correlation, with regions with higher Ks coinciding with regions with higher Macro in both megaplots. The spatial distribution of Ks and Macro in WT did not have a clear trend, while in T there was a slight stratification in strips interspersed with higher and lower Ks and Macro. These initial trends are not conclusive considering the short term between terraces removal and Ks and Macro evaluation.