Enhancements of Residual Soil Properties Using Vermicompost and Inoculant Strains in Low-Fertility Sandy Soil

Abstract

In Ethiopia soil fertility and productivity has been decline due to excessive use of chemical fertilizer, top soil erosion and organic matter depletion. This laboratory and greenhouse study was conducted to isolate effective rhizobium strain and vermicompost rate to improve the crop yield and soil properties. It was carried out using Dosha variety in 2020 to 2021. The factorial combination of three rhizobium strains (non-inoculated, RS-17 and RS-1035) and four rates of vermicompost (0, 5, 10 and 15 ton ha− 1) treatments were arranged in complete randomized design (CRD) with three replications. The result showed that rhizobium strains and vermicompost rate had brought significant (p < 0.05) influence on the biological and chemical properties of soils. Sole application of maximum rate of vermicompost (15 ton ha− 1) and rhizobium strain with RS-17 and RS-1035 significantly improve total number of microbial community. The crop inoculated by RS-17 responded the maximum number of rhizobium bacteria. Sole and combined application of 15 ton ha− 1vermicompost with RS-1035 or RS-17 strains produced large sized, deep red and fast growing rhizobium bacteria. On the other hand, the treatment that received combined RS-17and 15 ton ha− 1vermicompost was significantly improved soil’s pH by 6.2%, organic carbon (37.5%), available P (13.2%) and total N (1.5%) as compared with the control treatment. Moreover, it had the maximum microbial population (1.33×108cfu/g) and out of this 7.6×105cfu/g rhizobia population. However, to forward a compressive recommendation the experiment should be supported by field studies on different area soils.