Utilising agricultural waste to enhance food security and conserve the environment

摘要

Due to the increase in the world’s population and most of it moving to urban cities, there is increased demand for food, and this has resulted in the production of large amounts of agricultural wastes, both at farmer, municipality and city levels. The bulk of the agricultural food in developing countries is transported to cities in its raw form, thus compounding the net effect on large deposits of waste in urban markets, around homes and in slums as well as in various dumping grounds. In Kampala alone, over1000mt of waste accumulate in the city and only about 30% of it is collected by City Council leaving the rest to rot and pollute the environment. Although it is recognized that the accumulation of waste has enormous ill effects on humans and the environment, such wastes if properly managed could be considered a big bio-resource for enhancing food security in the smallholder farming communities that would notafford use of expensive inorganic fertilizers. These organic wastes contain high levels of Nitrogen, Phosphorus, Potassium and organic matter important for improving nutrient status of soils in urban agriculture. Various factors amplify the agricultural waste problem, especially in developing countries where there are limited facilities for recycling waste. A lot of the nutrients are leached from the damp fills and end up polluting rivers and water bodies, which have been associated with invasion of waterweeds. Most importantly, there is lack of planning, weak public awareness, weak government policy and laws, and lack of or insufficient utilization of resources. In Kampala many small holder farmers have improved milk production by feeding various combination of agricultural wastes and others have increased nutrient supply in soils by applying organic compost leading to improved crop yields, especially vegetables, maize which fetch high prices for the farmers thus reducing poverty levels and enhancing food security of these farmers . This alternate method of removal ofthese wastes for agricultural production by farmers has also reduced the rate of accumulation with subsequent reduction on environmental pollution thus improving on environmental health. This paper briefly reviews how agricultural wastes can be used to enhance food security and conserve the environment.