Introduction
1.1 Background of the Study
Despite her plentiful resources and oil wealth, poverty is widespread in Nigeria. The situation has worsened since the late 1990s, to the extent that the country is now considered the 20th poorest country in the world (IFAD, 2000). Feeding the rapidly growing population of Africa and Nigeria in particular has become a major development concern (FAO, 1990). Over 70% of Nigeria population is classified as poor, with 35% living in absolute poverty (IFAD, 2000). Poverty is especially severe in rural areas where social services and infrastructure are limited, with unstable income being a primary factor militating against their welfare (Enete and Achike, 2008). The great majority of those who live in rural areas are poor and depend on agriculture for food and income.
To meet the food and raw material demand of the growing population, agriculture must be approached on a sustainable basis (FAO, 2003). Sustainable development according to the Bruntland Commission is development that meets the needs of the present generation without compromising the ability of the future generation to meet their own needs (WCED, 1987). The struggle for food supply to catch up with massive population growth which is in a geometric pattern requires a consistently adequate level of soil fertility achieved in a sustainable way (Heckman, 2005).
Soil fertility, an element of natural capital, is key to the livelihood of the majority of the rural population of sub Saharan Africa who depend on agriculture as a central element in their livelihood strategy (Mangala, 2005). As agricultural production is the main source of economic activity in Nigeria, declining soil productivity means not only less food crops is grown but also that production of cash crops and income are endangered (FAO, 2001). The rural poor are often trapped in vicious cycle of poverty between land degradation fuelled by the lack of relevant knowledge of appropriate technology to generate adequate income and opportunities to overcome land degradation (FAO, 2000; Ojameruage, 2004).
Low organic matter coupled with low native nutrient status in most arable soil of Africa is responsible for low productivity and unsustainable production base (Fakoye, 2007). One of the most well known practices to recover and maintain the soil productivity is to add organic amendments (Westerman and Bicudo, 2003). Organic manure plays an invaluable role in rectifying land degradation and enhancing productivity thus achieving farm household food security, income and agricultural development (IFDC, 2007; Alimi, 2002).
As the population increases and puts pressure on diminishing resource, escalating environmental problems further threatens food production (IFAD, 2000). Increasing population pressure on the country has contributed to land degradation constraint leading to reduced size of land holding and consequently to reduced or zero fallow periods (Corsini, 1991). This has led to concerns over the long-term sustainability of agriculture. The reduced ability to use traditional soil fertility management practices such as fallow and crop rotation to restore soil fertility limit farmers’ productivity (Lal and Stewart, 1990; Dewitt, 2002).
Organic manure remains the major natural and sustainable means of rectifying soil fertility.
Biodegradable waste if well managed could be of immense help in ameliorating soil nutrient problem.
The extent to which agriculture can absorb municipal solid waste and contribute to poverty reduction, increased food security is still lacking among policy makers (Mkwabisi, 2005). The implication is that the financial costs associated with waste management are ‘ directly linked to food insecurity and soil fertility problems (Cave, 2001). Adeniyi (2008), attributed this to poor waste management, as plants nutrients that can be used for crop production, forestry programmes, landscaping, land restoration, soil improvement or animal feed are delivered to dumping sites.
One important consideration in dealing with wastes is to treat it as an important resource (Mercado, 2006). With the unlimited and available sources of biodegradable waste from metropolitan cities coupled with the unstoppable rise in prices of fossil-based fertilizers, organic manure production from municipal solid waste becomes a promising enterprise (Aganon, Roxas, and Dacumos, 1999) in (Mercado, 2006). By converting biodegradable waste to organic manure for crop production, a lot would have been saved to our foreign reserves due to reduction in fertilizer importation (Aganon et el., 1999) in Mercado 2006.
Dumping sites and landfills as methods of waste disposal occupy the limited scarce agricultural land, which would have been put into crop production. This thus, creates further problem on the scarce factor of production. The disposal of this form is unsustainable and a route to land degradation.
According to Senjobi et al., (2000), the disposal of organic wastes represent the loss of large amount of valuable resources, in particular nitrogen which is a limiting factor in most crop production. Despite the fact that a small portion of urban farms close to the dumping sites have benefited from the waste delivered by using them for crop production, Mkwabisi, (2005), affirms that the current trend in waste management has increased loss of soil organic matter which is important for nutrient storage, helps to maintain soil structure and interacts with trace metals to reduce their toxicity to plants. Meanwhile, all thisj opportunity cost is happening when the lives of many people are in danger with hunger, malnutrition and major diseases with agriculture facing a grim future due to high level of soil infertility (Alimi et al., 2006; Kim, 1998).
Since agriculture is very crucial to the social and economic development of the nation, a sustainable approach should be embraced. All over the world, the concept of evolving strategies for ensuring food security under a sustainable environmental management has gained prominence (NEEDS, 2004). Agricultural production should focus not only on yield but conservation mechanism. Conservation is described as option used to maintain the essential features of the natural habitat (Young, 1998; Mulongoy, 1986). It is also defined as a process by which the life of resources is prolonged either by preserving, re-using or by re-cycling it (FAO, 2000). The production of agricultural crops which give high returns per unit of input used is a major challenge in an effort to achieve food security, economic growth and sustainable development while maintaining the integrity of the environment (WCED, 1987).
Organic manure use has been classified as sustainable conservation technique. Its use in crop production especially in the tropics holds a lot of potentials (Westerman AND Bicudo 2003). This research work therefore, takes an insight into unfolding the potentials of organic manure use in ameliorating the problems of nutrient status of the soil, reduction in cost and unavailability of artificial fertilizer and most importantly is restoring environmental quality.
The interest in organic manure in African agriculture is not necessarily the same in the developed countries, where the overwhelming issue is on environmental and health consciousness (Nwajiuba and Akinsanmi, 2002). In Africa it is the damage to the soil and scarcity of inorganic fertilizer provision as and when due that gives prominence to the use of organic manure. Africa has the lowest mineral fertilizer consumption, about 10 kg nutrient (N, P2 O5, K2O) per hectare per year compared to the world average of 90 Kg or 60 kg in the near East and 130 kg per year in Asia (FAO, 2001).
The low inorganic fertilizer utilization in African, Nigeria inclusive has prompted researches into indigenous soil conservation mechanism. Indigenous soil conservation can be referred to as the local means of combining crop production and soil management practices that are likely to protect the soil again.
