The use of soybean biomass ash and bacterial inoculums as the treatment in acidic soils to improve soil and barley plant quality

Abstract

The purpose of this study was to evaluate the effect of biomass ash from combustion of soybean straw alone or in combination with bacterial inoculums on yield of barley crop, and on soil and plant quality. The greenhouse pot experiment included four treatments and two control soils (control without any amendment - ØØ and control with mineral fertilizer ØØ+CAN, 0.3g CAN/pot). Treatments included soil (3 kg/pot) and biomass ash (30 g/pot) without and with one of three selected bacterial inoculums. Bacterial strains Streptomyces fulvissimus CKS7, Hymenobacter sp. CKS3 and Sinorhizobium (Ensifer) meliloti 207 were used for three inoculums preparation (CKS7, CKS7+CKS3 and 207). The ash and experimental soil samples, as well as soil and plant samples collected at the stage of crop maturity were tested for: total N, C, S, plant available P2O5 and K2O and for the content of potentially toxic and hazardous microelements (As, Cd, Сo, Cr, Cu, Mn, Ni, Pb, Zn). The results showed that the addition of biomass ash significantly reduced soil acidity and increased content of plant available P and K compared to the controls (in all treatments). Barley yield was almost twice as higher in ash treatment and by 1.56, 1.70 and 1.81 times higher in treatments Ash+CKS7, Ash+CKS7+CKS3 and Ash+207 respectively, compared to control (ØØ). The content of potentially toxic microelements was below the maximum allowed concentrations in the soils and shoots. The use of combinations of ash and bacterial inoculum improved the quality of barley in terms of nitrogen content. This study showed that biomass ash can be used as fertilizer on acidic soils with low nutrient content alone or in combination with applied inoculants and provide an environmentally friendly approach in agriculture to reduce the need for chemical fertilizers and solve the problem of biomass ash disposal.