Functionality of Soil Microorganisms in Bio-conservation of Water and Soil

Abstract: Soil erosion is a major concern worldwide and serious eco-environmental problem and an important driver of soil loss and water sources. Hence, it is necessary to provide appropriate biological solutions and implement proper measures aimed at controlling soil erosion and runoff generation. Application of soil amendments and additives is one of the technical-managerial approaches considered to enhance soil stability against degradation agents. One of the new and biological technique in the conservation and management of soil and water resources is the use of native soil microorganisms extracted from the same area. Soil microorganisms are resistant to various environmental stresses such as high temperature, drought, UV, freezing and other stresses. In response to extreme and variable conditions, consortia of several species can develop firm layered structures, microbial mats, or biofilms. The inoculated soil microorganisms, especially bacteria and cyanobacteria through their polysaccharide and exopolysaccharide secretions, cellular elasticity, connecting to soil fine particles via cell adhesiveness. They also stay in the space between proliferation and developing filament networks and binding to aggregates. Besides water abstraction of rainfall and the creation of surface soil microchannels, they increase soil permeability and resistance stress which can tackle the effects of raindrop splash through water absorption and creation a protective layer around soil particles. It ultimately reduces runoff yield and soil loss. Soil microorganisms also can contribute considerably to soil organic matter and exert critical control over soil organic carbon stabilization in the global carbon cycle, soil recovery and stability as well as increase nutrient accumulation and soil fertility. According to the study conducted by the authors, by extraction and proliferation of soil microorganisms from an area under freezing-thawing conditions, their performance was evaluated in laboratory conditions. The results of their research showed that the direct inoculation of soil microorganisms into the soil decreased mean runoff volume by 73% and increased time to peak by 56%. Further, a decrease of some 78% in mean sediment concentration and a decrease of 89% in total soil loss were ascertained. Hence, creating artificial biological soil crusts by native soil microorganism inoculation is novel step in achieving biological tools to increase soil stability against soil erosion. The direct inoculation of soil microorganisms therefore could be supposed as a rapid, persistent, environmentally sound, economically efficient, and technically appropriate biological tool for conserving soil and water resources.