U. R. Sangakkara
Department of Crop Science, Faculty of Agriculture, University of Peradeniya, Sri Lanka
Full Paper (PDF File: 263KB)
Organic farming systems are evolving rapidly in all parts of the world, to meet the demand for pollutant free food for humankind. Furthermore, these systems have been identified as alternative and sustainable units to maintain productivity in contrast to current chemical food systems. However, due to lower concentrations of nutrients available in organic manures and the requirement of very large quantities of these materials, nutrient use efficiencies of crops play a deterministic role in maintaining productivity of organic farming systems.
Effective Microorganims (EM) is proven to increase productivity of organic farming systems in all climatic zones. However, the mechanisms of action of EM are not well defined. Thus field studies were undertaken to evaluate the role of EM on selected soil properties and root development patterns of a selected legume, mungbean, over two seasons, along with nutrient uptake efficiencies when grown in different organic systems.
Application of organic manures enhanced water holding capacities and reduced bulk densities of soil. Application of EM enhanced these processes. Thus the root growth of mungbean was enhanced, resulting in greater branching, especially in terms of secondary and tertiary branches, which are responsible for nutrient and water uptake. Furthrmore, nodulation was also increased by the application of EM, due to the presence of more sites of inoculation. The utilization efficiencies of applied and soil nitrogen and potassium were also increased by EM. The impact of the microbial solution was greater when supplied with organic matter with a low C:N ratio. The resultant effect was greater yields of mungbean, which was significantly correlated with nutrient uptake efficiencies.