Effect of land disposal of stillage on exchangeable cations and other nutrients in the soil

Abstract

In laboratory, increasing volumes of stillage (equivalents to 50, 100, 150, 200 and 400 m³ /ha), with and without addition of N and P, were incubated with a Typic Paleudult soil, and the effects on exchangeable cations and other nutrients in the soil were studied. Total N and C levels were not affected. Exchangeable K, Ca and Mg levels increased with the increasing levels of stillage applied. However, in each treatment, Ca and Mg increases were higher than the amounts of these elements introduced in the soil by the dose of stillage. The levels of exchangeable Na were not affected with the increasing levels of applied stillage. The soil pH increased while the levels of exchangeable Al, available P and nitrate decreased. The point of zero charge (p.z.c.) determined for the soil treated with 400 m³/ha of stillage, with and without addition of N and P, did not differ from the value of the untreated soil. The addition of N and P to the stillage did not affect the general trends observed for the soil treated with stillage. However, the levels of ammonium, which were constant for the different treatments with stillage without N and P, tended to decrease during incubation for the treatment with stillage plus N and P.