Evaluation of leaching and runoff losses of selenium from seleniferous soils through simulated rainfall
2008
Dhillon, Surjit Kaur | Dhillon, Karaj Singh | Kohli, Anshuman | Khera, Kishan Lal
Experiments were conducted to study drainage and runoff losses of selenium (Se) from two seleniferous soils (from Simbly containing total Se 850 μg [kg soil]⁻¹ and from Barwa containing 1310 μg [kg soil]⁻¹) under simulated rainfall (250-260 mm in three rainstorms) conditions. Rainfall intensities ranged from 56 to 120 mm h⁻¹ with uniformity coefficients ranging from 70.6% to 84.2%. Selenium lost through drainage (sum of drainage from initially saturated soil for 24 h and through dry and wet runs) was 0.15% and 0.11% of total Se content in the two soils. In soils having similar pH and organic-C content, losses of Se through drainage as well as runoff were defined by total Se, water-soluble Se, CaCO₃ content, and texture of the soils. The amount of runoff water was almost two times in the soil with fine texture and less infiltration rate than in the other and that same trend was observed with respect to loss of sediment. The soil with higher CaCO₃ content and water-soluble Se lost more Se with moving water both through leaching and runoff, whereas the other soil with fine texture lost greater amount of Se with the sediment. Total Se lost through drainage as well as runoff was 0.29% of the native Se present in both the soils suggesting that significant amount of Se could be lost from seleniferous soils during irrigation and rainfall events.
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