Effect of cattle manure on selenate and selenite retention in soil

Abstract

The aim of the present investigation was to study the effect of manure on retention of selenium (Se) in soil. Addition of cattle manure in combination with selenite and selenate reduced the adsorption of both anions to a loam soil in a batch experiment. The results were explained by the content of low-molecular-weight organic acids in the manure which compete with Se for the sorption sites. In a pot experiment with loam and peat soils and with two pH levels within each soil, cattle slurry added together with selenate was found to increase the Se concentration in grain at the highest pH level (6.1 and 6.8 for the loam and peat, respectively). At a lower pH (5.4 and 6.0 for the loam and peat, respectively) there was no significant effect of slurry on Se concentration in grain. Application of slurry also increased the residual effect of Se applied to the loam soil in the preceding growing season. In the peat soil, no residual effect of Se was found either with or without the addition of slurry.