LAUSR

Soil micro-organisms influence soil ecosystem processes and properties. Their influence can be modified by cultivation practices, which affect their interaction with cultivated plants as well as soil physical and chemical properties. The study investigated differences in soil microbial activities between cultivated maize fields with a bioslurry application and non-cultivated land. Bioslurry crust and soil samples were collected from two farms located in the Free State province of South Africa. For soil microbial analysis, which included functional diversity and soil microbial enzymatic activity, soil samples were collected from the maize fields where bioslurry was applied and outside where no bioslurry was applied, as a reference. Liquid bioslurry and bioslurry sediment were scooped separately from digesters on the same farms for nutrient analysis. Community substrate utilisation profiles were assessed using Biolog EcoPlatesTM to determine functional diversity. Soil microbial enzymatic activities were assayed by measuring β-glucosidase, alkaline phosphatase, acid phosphatase and urease activities in the soil. The bioslurry crust had the highest nutrient content in comparison to bioslurry and bioslurry sediment. Principal component analysis showed differences in carbon source utilisation profiles between the different samples. Soil microbial populations present in the bioslurry crust and soil supplied with bioslurry were more similar, compared to those present in the untreated soil. The bioslurry crust sample demonstrated the highest overall enzyme activities. The study showed that the bioslurry and bioslurry crust could be used as organic soil amendments, with positive effects on soil health and fertility, contributing towards sustainability of the environment and ultimately to food security.