Abstract

This project attempted to evaluate the agronomic and environmental characteristics of ash, which is a waste product generated during energy production from coal and bagasse (coal ash and bagasse ash, respectively). Ash is produced in large amounts and its injudicious disposal into the environment can have adverse consequences for human, plant, and animal health (Kumar et al, 1998). The best strategy would be to convert this waste into a resource that can be utilised, for instance in agriculture (Munbodh, 1995; Lalljee, 2000; Bhantoo, 2002; Lalljee, 2006) and construction. This project investigated' and developed the optimum rate and frequency of ash application (to soil to improve soil properties, control pests, and enhance crop growth and yield. The study also investigated" the effect on soil biodiversity. Scientific data from the experimental work was statistically analysed. Many soils in Mauritius are acidic, and under such conditions, plants are able to take up very small amounts of nitrogenous, phosphatic and potassic nutrients, and hence, even large scale additions of fertilizers and compost can fail to provide the essential nutrients to the crop. On the other hand, high alkalinity too can have a similar effect (although the reason for the unavailability of the nutrients is not the same). Moreover, Mauritian soils are deficient in silicon (Lalljee, 2008). Ash has the potential to reduce soil acidity and serve as a soil amendment and conditioner. Ash can also help in pest control by its abrasive effect on soft-bodied pests such as molluscs and insect larvae. However, it is necessary to investigate the appropriate rate, frequency and mode of application to ensure that the effects of ash are optimized, and that there is no toxicity to the plant or soil resulting from excessive application. This project will help (i) reduce the amount of ash that would need to be disposed of into the environment, (ii) provide a locally-produced, easily available, soil amendment and crop control product which can be used in conventional and organic agriculture, the latter in itself being a high value-added activity envisaged by the Government, (iii) reduce consumption of synthetic fertilisers in conventional agriculture, and hence help make it more environment friendly and sustainable, (iv) add value to the ash, (v) increase the income of flexi-factories, and State-owned and Independent Power Producers through the sale of this by-product, and create business opportunities for Small and Medium Enterprises (SMEs).