Water erosion in soybean farming areas under different soil covers and simulated rainfall patterns in the Southern Amazon, Brazil

Abstract

Controlling water erosion is a challenge for agricultural producers, especially in extensive soybean production areas. This study aimed to evaluate soil and water losses in soybean farming areas under different soil cover conditions and simulated rainfall patterns, on a typic Hapludox in the Southern Amazon region. A factorial arrangement was used to assess four soil cover conditions (soybean over corn straw − SS, straw only − SO, no cover − NC, and no cover with soil tillage − NT) and four rainfall patterns (Advanced − AV, Intermediate − IN, Delayed − DE, and Constant − CT). Rainfall simulations were performed by InfiAsper equipment, producing an average precipitation intensity (PI) of 75 mm h⁻¹, a maximum PI of 133.1 mm h⁻¹, and a duration of 60 min. Regardless of soil cover conditions, DE rainfall pattern provided the longest runoff start time (19.15 min), while the AV pattern had the shortest end time (45.87 min). Soil cover removal resulted in an average maximum runoff rate of 80.9 mm min⁻¹, 50.9 % higher than the SS and SO conditions. This effect was also observed for runoff depth (64.4 %) and sediment loss (1,173 %), especially in NT areas. IN and DE rainfall patterns produced significantly higher average maximum runoff rate (89.32 mm min⁻¹) and soil losses (5.69 g m⁻²) compared to the AV and CT ones (45.21 mm min⁻¹ and 2.48 g m⁻²). These results demonstrate the importance of conservation practices, such as maintaining crop residues and soil cover, in reducing erosion in agricultural areas.