Impact of cover crops on soil physical properties, soil loss and runoff in compacted Oxisol of southern Brazil

Abstract

Soil compaction can increase soil erosion owing to runoff and soil loss. Cover crops are an option for the sustainability of agricultural systems. The objective of this study was to evaluate the effect of cover crops on soil physical properties, soil loss, and runoff in a compacted Oxisol. The plots were then compacted using a drum roller. Ten cover crops, mixed or single, were used, and maize (Zea mays L.) monocrop was used as a control. Bulk density (BD), total porosity (TP), macroporosity (MaP), microporosity (MiP), and saturated hydraulic conductivity (Ks), were determined in the layers 0–0.1, 0.1–0.2, and 0.2–0.3 m. Within each experimental unit was allocated the collecting drains to measure soil losses and runoff during natural rainfall. The cover crops rye (Secale cereale), sunn hemp (Crotalaria juncea), and sunn hemp (Crotalaria spectabilis) improved most of the physical properties of the compacted soil compared to the maize monocrop. The cover crops did not decrease soil loss and runoff in some periods compared to the maize monocrops, especially during high rainfall seasons. This result suggests that reducing the soil loss and runoff of a compacted Oxisol should be expected in the long term in comparison to soil physical properties that were improved in the short term.