Inorganic phosphorous, lime and vermicompost induced changes on phosphorus fractions and other properties of acidic Soil of Cheha district, Ethiopia

Abstract

In acid soils, soluble inorganic phosphorus is fixed by aluminum and iron, so that phosphorous availability to plants would be inhibited. Thus, an incubation study was conducted to evaluate the effects of lime, vermicompost, and mineral P fertilizer on the distribution of P fractions, oxalate, dithionite extractable aluminum, and iron. The treatments consisted of three rates of phosphorous (0, 74.51, and 149.01 kg P ha-1), three rates of vermicompost (0, 5, and 10 ton VC ha-1), and four rates of lime (0, 5.70, 9.20, and 11.50 ton CaCO3 ha-1). The experiment was laid out as a complete randomized design in a factorial arrangement. The results revealed that the combined application of lime, vermicompost, and mineral P significantly (p<0.05) increased labile phosphorus fractions and decreased the potential sorption capacities of the soil. As soil pH increased, exchangeable acidity and oxalate extractable Fe and Al decreased. The integrated applications of these amendments fixed aluminum and iron instead of phosphorus, thus rendering phosphorus available by keeping the inorganic phosphorus in a bioavailable, labile phosphorus pool compared to the sole application of the amendments. The combined applications of lime, vermicompost, and inorganic P to acidic soils at the Goha sampling site in Cheha district could convey an enhanced amount of available P and ensure the maintenance of higher levels of labile P. It might also contribute towards meeting crop P requirements.