Promoting Innovative Composting Alternatives of Agricultural and Municipal Waste
Mon, Nov 24. 12:00AM - 3:00AM
To meet the food requirements of Africa's ever-growing population, it is estimated that food production will need to grow from 40 percent to 100 percent over current levels. The lower end of the range is the minimum to maintain the status quo in food production per capita. Intermediate estimates take into account the desire to meet Millennium Development Goals (MDGs) for reducing hunger and poverty. Estimates at the higher end also take into account the likely rise in food demand from a growing middle-class in most African countries, particularly with respect to increasing consumption of animal-based protein which requires increased levels of grain production. Under any scenario, the absolute growth in food supply required is unprecedented in Africa's history.Unfortunately, Africa has the most depleted soils in the world, with the annual nutrient loss from the continent’s soil estimated to be about US $4 billion. Particularly in Sub-Saharan Africa, nutrients removed through crop harvests are at least four times more than nutrients returned to the soil in the form of manure and fertilizer, resulting in excessive negative nutrient balance in croplands. There is a critical need to reverse the trend of soil nutrient depletion and to meet the food requirements of the growing populations and protect the environment for future generations.
While declarations of the African Union Member States at the Abuja Fertilizer Summit in 2006 that “fertilizer, from both inorganic and organic sources, is a strategic commodity without borders” have given considerable political momentum to issues of soil nutrient depletion, affordability of fertilizers remains a key constraint to intensification.This constraint is exacerbated with the price volatility of the primary inputs (i.e., natural gas) for the production of inorganic fertilizer. From this perspective, integrated soil fertility management where the use of organic materials as a complement to chemical fertilizers can be promoted, with the recognition that in the short-term, inorganic fertilizer will continue to provide the main sources of plant nutrients and organic fertilizers alone cannot provide the marginal yield increases needed to achieve food security in Africa.
Large quantities of solid waste are generated in urban areas of all African nations, which include household, market, horticultural and agricultural waste. The average solid waste generation is about 0.4-0.6 kg/person/day for most African countries. The high content of organic matter (50-90 percent) provides an opportunity for exploitation through composting processes. However, rather unfortunately, in African countries, organic manure resources are no longer fully explored or exploited. Unlike in rural communities, there is usually little or no return of food biomass and related nutrients into the food production process. Most waste ends up in landfills or pollutes the urban environment.This is transforming cities into vast nutrient sinks, while the rural production areas are becoming increasingly nutrient deficient. For example, statistics in Ghana show that in Accra and Kumasi, 255,000 to 366,000 and 230,000 to 250,000 tons of organic waste, respectively, are effectively available annually for composting, meaning that these amounts are already collected and have no other current use. The nutrient content of this waste in Accra alone is estimated at 3,500 to 5,300 tons per year of nitrogen, 1,700 to 2,600 tons per year of phosphorus and 760 to 1,100 tons per year of potassium. These amounts could easily cover the entire nutrient demand of urban farming in Ghana.
More recently, pilot programs in some African countries such as Burkina Faso, Ethiopia, Ghana and Nigeria have already indicated that the recycling of waste for fertilizer can be done with the development and transfer of safe sound plant nutrient technology.The productive use of municipal and human waste to generate fertilizer offers an important source of plant nutrients to improve soil fertility, yields and food security in Africa. The training program is therefore designed to build the capacity of the participants to take full advantage of the enormous municipal and human wastes generated in order to improve agricultural productivity and move toward food security in Africa. The training seeks to address the type of storage/collection and treatment needed in order to determine how much of these resources can be recovered and harnessed, and at the same time, how safe the final product is for the end-user. The training will promote the productive use of municipal and human waste, in addition to agricultural waste, for fertilizer in Africa based on existing initiatives on the continent.