Agriculture and Horticulture

Biography

Biography: Manaka Makgato

Abstract

Increasing human population, decrease in resources and environmental degradation pose serious threat to natural processes such as critical microorganisms that are responsible for life on earth. Agriculture is challenged to develop strategies for sustainability that conserve non-renewable natural resources such as soil. Good agricultural produce and sustainability depend on the soil health maintenance. Soil health is the capacity of a soil to function as a vital living system, within ecosystem and land use boundaries in order to sustain plant productivity and promote plant health. In this study, we assessed soil microbial diversities of Sutherlandia frutescens soils which are responsible for availability Nitrogen (N), Phosphorus (P) and Carbon (C). The experiment was conducted on the experimental site at the Agricultural Research Council (ARC VOPI) Roodeplaat, Pretoria, South Africa (25°59’S; 28°35’E). The experimental layout was a Latin square with four levels of inoculant per 100 seeds (T0=Control, T1=1gram Inoculant, T2=2grams inoculant and T4=4grams inoculant) replicated four times. Plants and soil samples were collected for analysis. Rhizosphere and Bulk soil samples were sent to ARC’s Plant Protection Research Institute (ARC PPRI) for Carbon Substrate Utilisation Profiles (CSUP), functional diversity and soil microbial enzymatic activity. The data obtained were subjected to non-parametric statistical analysis using STATISTICA 12 (StatSoft, Inc. ©) and Principal Component Analysis (PCA) and cluster analyses. There was significant statistical difference existed between the CSUP of soil microbial populations. It was clear that CSUP in T0 and T4 differ significantly from T2 but not from T1 and the bulk soil. Nutrients composition released over decomposition or the plant root exudates attract microbial populations that are specialized to utilize the specific compounds rapidly, thus contributing to the difference in CSUP of soil microbial populations. Soil microbial populations differed in sampled plots but not statistically significant in their ability to convert C. There was lowest ß glucosidase activity in T2 and Bulk soil; T2 and T4 had the lowest alkaline phosphatase activities whereas T0, T1 and T4 had the lowest acid phosphatase; and T0 and T4 had the lowest urease activities. Soil microbial diversity and activities did not differ significantly between the sampled treatments. The samples revealed that the overall lowest soil microbial diversity with the highest overall soil microbial activity in the Bulk soil, compared to the other treatments. Considering the results obtained, the soil samples do not represent the profile of healthy soils, which might make the soils prone to unhealthy plants or lower yields due to low microbial activity, and the occurrence of diseases due to the low microbial diversity.