Does soil granulometry influence leaching rates of potassium even after administration of increasing irrigation depths?

Abstract

Cerrado has soils characterized by high rates of nutrient losses, either by runoff or leaching, caused mainly by rainfall intensity in the region. Among nutrients, potassium, due to its characteristics, has great potential of being lost by leaching. Thus, this study evaluates the effect of application of potassium (K) fertilizer and different irrigation depths on the potential for K leaching in soils with different granulometries. For this purpose, 60 undisturbed soil monoliths were collected and distributed in soil samples with three different granulometric ratios. The experiment was performed in a mesocosm with a randomized block design in a factorial scheme with three replicates, consisting of five doses of potassium (0, 50, 100, 150, and 200 kg ha−1) and four irrigation depths (50%, 100%, 150%, and 200% of the irrigation depth obtained in the field capacity). Potassium leaching was evaluated over 80 days of incubation, as well as the potassium remaining in the soil at the end of the experiment. The data demonstrated the effect of application of irrigation depths on the sandy loam soil. As the clay content increased, irrigation depths did not affect the K content leached. Thus, this study demonstrated that different irrigation depths on the soil may not affect the potassium content remaining in the system.