Loss of nitrogen, phosphorus, and potassium through surface runoff under simulated rainfall in different soil management systems

Abstract

Abstract The surface runoff in agricultural areas can carry soil chemical elements, causing environmental and economic problems. Nutrient losses through surface runoff can occur in both particulate and dissolved forms, influenced by soil use and management systems. In this context, the objective of this study was to quantify the losses of N (NH4+ and NO3-), P, and K in dissolved and particulate forms in samples from a simulated rainfall event of 60 mm h-1 with a duration of 20 minutes, after the onset of surface runoff. The study was conducted in experimental plots in a randomized block design, with four treatments and two replications. The treatments were defined as T1 (fallow with spontaneous vegetation), T2 (irrigated rice under conventional tillage), T3 (no-tillage irrigated rice in monoculture), and T4 (no-tillage rice in crop rotation). The rainfall was applied in pre-seeding of irrigated rice, crop 2022/2023. The results showed that the highest losses of NH4+ and NO3- occurred in treatments T2 and T3 compared to the others. Regarding nutrient loss, treatments T1 and T2 showed the highest losses of P and K, with a greater presence in the soil fraction (particulate).