Soil conservation is a complex bio-physical, social and economic challenge – the major interactions in play are diverse and interconnected. Soil conservation research, education, and policy have the potential to improve the potentials of soil resources by broadening the range of options available to land managers. This study assessed the economic analysis of soil conservation practices among farmers in Atiba Local Government Area, Oyo, Oyo State, Nigeria. Sampling involved a number of probability and non- probability methods such as simple random sampling and purposive sampling methods respectively. The study employed descriptive statistical tools for the analyses of the data collected and also for the presentation of results. Findings showed that the soil conservation techniques employed include cover crop, improved fallows, multiple cropping, intercropping, minimum tillage, no-till, ridge tillage, conventional tillage, waterways, mulching, contour bunds, and terraces and that 86% of sampled farmers use at least one type of soil conservation technique. The most widely employed soil conservation techniques are mulching, cover crop, multiple cropping, improved fallows and intercropping. The most common factors responsible for the choice of these soil conservation methods are type of crop grown and traditional practice. Other common factors include size of farmland, physiographic attributes of the farmland, etc. Also, it was found out that 45% of the farmers that employ one soil conservation method or the other perceive the method(s) employed as moderately effective and 31% perceive the method(s) as highly effective. This also means that 76% perceive the method(s) as at the least moderately effective. At the same time, 7% maintained that the conservation techniques are marginally effective, 3.1% maintained that the soil conservation techniques are not effective.
1.1 BACKGROUND TO THE STUDY
One of the unique characteristics of rural communities in many developing countries across the world are the total dependence on agriculture for their livelihood. Therefore, since almost all rural households depend directly or indirectly on agriculture and given the large contribution of the sector to the overall economy agriculture is a key component of growth (IFPRI, 2007). Of the projected increase in world population of about 3 billion between 2008 and 2050, about half of it may occur in Africa where soil resources are already under great stress. The agrarian stagnation, plaguing food security in sub-Saharan Africa (SSA) since the early 1970s, may exacerbate with the projected climate change along with the attendant increase in risks of soil and environmental degradation (Birte et al., 2008). For example, the Nigerian population has increased from 115 million in 1991 to 140 million in 2006 (Federal Republic of Nigeria, 2007).
Root and tuber crops are second only in importance to cereals as a global source of carbohydrates. They also provide some minerals and essential vitamins, although a proportion of the minerals and vitamins may be lost during processing as, for example, in the case of cassava. The quantity and quality of the protein in starchy staples are variable and relatively low on a fresh weight basis but compare favorably with some cereals on a dry weight basis. In most traditional diets vegetable soups, meat, groundnuts, grain legumes and fish are good sources of protein and are frequently used to supplement root crops and compensate for their protein deficiencies. It is better for the root and tuber crop farmers to concentrate on soil conservation methods that would increase the land productive capacity rather than the methods that would increase crop productivity within a short time and thereafter causes havoc to the soil. In the olden days, shifting cultivation and bush fallowing systems were the best methods of conserving soil fertility as a result of vast land available for crop production. Shifting cultivation is fast dwindling especially in north central Nigeria as a result of the different ways lands are being used; road construction, land excavation for different purposes and yearly cultivation of land without rest are the various ways in which nutrients are being mined with little attention in replacing the nutrients mined and depleted (FAO, 2013).
Soil, with the potential to nurture crops of great varieties, is one of the most important components of the lithosphere. It is an invaluable resource that results from nature’s efforts over tens or hundreds of thousands of years. However, human efforts can destroy this resource in only a few years.
Among natural resources, none has been of greater significance than soil resources. Soil is a non-renewable resource over the human time scale. It is dynamic and prone to rapid degradation with land misuse. Productive lands are finite and represent only less than 11% of earth’s land area but supply food to more than six billion people increasing at the rate of 1.3% per year (Eswaran et al., 2001). Thus, widespread degradation of the finite soil resources can severely jeopardize global food security and also threaten quality of the environment (Blanco and Lal, 2008).
Land degradation was a significant global issue during the 20th century and remains of high importance in the 21st century as it affects the environment, agronomic productivity, food security, and quality of life (Eswaran et al., 2001). Soil degradative processes include the loss of topsoil by the action of water or wind, chemical deterioration such as nutrient depletion, physical degradation such as compaction, and biological deterioration of natural resources including the reduction of soil biodiversity (Lal, 2001).
Land degradation, soil erosion, and nutrient depletion contribute significantly to low agricultural productivity—and thus food insecurity and poverty—in many hilly
areas of the developing world (Pagiola, 1999; Nkonya et al., 2006; Shiferaw, Okello and Reddy, 2007). Crop yields and agronomic productivity are also constrained by recurring drought stress exacerbated by scarcity of renewable fresh water resources and highly variable/unpredictable rains. The problem of land scarcity for food crop production is aggravated by rapid urbanization, conversion to non-agricultural uses, and severe soil degradation. Land area affected by soil degradation in Africa is estimated at 227 million hectares (mha) by water erosion, 186 mha by wind erosion, 19 mha by physical degradation, and 62 mha by chemical degradation, of which 15 mha is by salinization (Junge et al., 2008). In Nigeria, West Africa, human-induced soil degradation is a common phenomenon. Its severity is light for 37.5% of the area (342,917 km2), moderate for 4.3% (39,440 km2), high for 26.3% (240,495 km2), and very high for 27.9% (255,167 km2) (UN Food and Agriculture Organization, 2005).
Soil erosion is the most widespread type of soil degradation in the country and has been recognized for a long time as a serious problem (Stamp, 1938). In 1989, 693,000 km2 were already characterized by runoff-induced soil loss in the south and 231,000 km2 were degraded, mainly by wind erosion, in the north. Sheet erosion dominates all over the country, whereas rill and gully erosion are common in the eastern part and along rivers in northern Nigeria (Ologe, 1988; Igbozurike, 1989).
Redistribution of soil by erosion and deposition is the result of perturbation and a natural landscape-forming process. However, it has been greatly accelerated by human activities in recent decades as the traditional shifting cultivation system has been replaced by more intensive but generally unstable cropping systems (Lal, 1993a). The main reason for the land use intensification was and still is the increase in food production required to feed the rapidly growing population. For example, the Nigerian population has increased from 115 million in 1991 to 140 million in 2006 (Federal Republic of Nigeria, 2007). In order to maintain soil losses within tolerable limits, similar to those which occur in nature, as for example in a forest, a farmer must cause minimum soil disturbance regardless of the situation and the agricultural activity. Therefore, soil and water conservation techniques remain an indispensable tool in sustaining crop production especially on farm lands under severe soil degradation.
1.2 STATEMENT OF PROBLEM
Of the projected increase in world population of about 3 billion between 2008 and 2050, about half of it may occur in Africa where soil resources are already under great stress. Because of the increase in population, the per capita arable land area in many countries of sub-Saharan Africa is declining rapidly. The per capita land area (ha) in 1960, 1990, and 2025, respectively, is 0.14, 0.08, and 0.03 for Congo; 0.50, 0.29,
and 0.11 for Ethiopia; 0.31, 0.13, and 0.05 for Tanzania; 0.50, 0.28, and 0.14 for Zimbabwe; and 0.68, 0.34, and 0.14 for Nigeria (Junge et al., 2008). Thus, avoidance of soil loss by improved management and the conservation of natural resources are therefore important to maintain the functions of the soil and contribute to food security today and for future generations (Ehui and Pender, 2005).
Soil degradation and desertification are already severe issues in sub-Saharan Africa, where smaller size and resource-poor farmers follow extractive farming practices. These farmers can neither afford the much needed off-farm input essential to sustainable use of soil and water resources, nor are they sure of their effectiveness because of the harsh climate, structurally fragile soils, unfavorable land tenure situations, and the human dimensions issues of gender and social inequity.
The expansion of agriculture into marginal areas, deforestation, the shortening
or elimination of fallows, inappropriate farming practices, and low input inevitably have several environmental and economic impacts, especially in sub-Saharan Africa where the resilience ability of the soil is limited (Lal, 1995a). This expansion of agriculture causes on-site degradation of natural resources and productivity decline. For example, Mbagwu et al. (1984) observed that soil erosion causes a yield reduction of about 30% to 90% in some root-restrictive shallow lands of southern Nigeria. Off-site problems, such as the siltation of reservoirs, are also common consequences of soil loss. Hence, low agricultural production, food insecurity, low income of the rural population, and poverty are some of the consequences of soil erosion (Junge et al., 2008).
The traditional farming systems that farmers have previously employed to sustain their productivity cannot any longer effectively work due to population pressure. Farmers have perceived a decline in soil productivity, and continued water shortages (Chomba, 2004). They consider these problems to be a natural course, which cannot be avoided (Siachinji-Musiwa, 1999). The effects of soil degradation and water shortages on crop productivity have induced researchers to introduce some innovative practices such as mulching, bunding, contour ridging, ripping, minimum tillage and others to check the downward spiral in agricultural production (Chomba, 2004). Varied soil and water conservation practices requiring varied farmer inputs have been promoted among farmers for over a decade now (Chelemu and Nindi, 1999; Haggblade and Tembo, 2003a; Mulenga, 2003).
Over the centuries, intensive systems of soil and water conservation have been developed and practiced by local farmers around the plains of Atiba Local Government Area. Conservation farming techniques such as hillside terraces, stone-lines and bunds, trash-lines, sand-bag lines, earth-contour bunds, crop rotation, rice-bran mulch, vegetation-barriers and organic manuring utilize natural ecological processes to conserve moisture, improve soil structure, curtail soil erosion and enhance soil fertility (Morgan, 1986). Safe disposal of runoff water involves practices such as the physical manipulation of soils, which includes land shaping, construction of contour-bunds, terraces, waterways and ridges as measures to improve water infiltration and conservation (Ray, 2006).
However, in recent years, adaptation of incompatible technologies on some soil environments has been noticed with limitations that have put most arable lands into perpetual degradation (Anon, 1999). Thus, farming activities are adversely affected due to diminishing productive capacities of the soils (Lal, 1995). Consequently, crop returns often deplete sharply and reflected in prohibitive food dearth and starvation among human population (Olawoye, 2000).
Recently in a study carried out by Egbetokun et al. (2014), degradation was established as a major cause of technical inefficiency of the farms in Oyo state and this has been linked to farm practices such as shortened fallow, bush burning, conventional tillage and animal grazing. They reported that in Oyo state 68% of the farms had slight land degradation problem, 4% of the farms had severe degradation problem, 13% had moderate degradation problem while only 15% had no sign of degradation at all. Also, it was pointed out that the farms with no degradation problem at all were the most productive with an average technical efficiency of about 94% while the farms with severe degradation were the least productive with an average technical efficiency of about 28%. This implies that the severe the land degradation status of the farms, the more technically inefficient they become. In the reverse, land degradation negatively affects farm productivity (Egbetokun et al., 2014).
Although, many research works have been conducted to address the issue of soil management in the country as a whole, only few has been done to look into soil conservation practices in Atiba Local Government Area, one of the few largest Local Government Areas in Oyo state. Therefore, assessment of localized soil and water conservation practices in an intensively cultivated environment such as Atiba Local Government Area is of paramount importance. In view of this need, the present study was conducted in order to assess the efforts being made by farmers in conserving soil on the farms of Atiba Local Government Area and suggests ways by which the practices adopted can be improved in the face of seemingly unavoidable soil loss.
1.3 AIM AND OBJECTIVES
The aim of this study is to assess the economic analysis of soil conservation techniques among farmers in Atiba Local Government Area, Oyo, Oyo State, Nigeria. The specific objectives are to:
- identify the soil conservation techniques adopted by farmers in the study area;
- determine the most common techniques employed;
- identify the reasons for their dominance and;
- assess the perception of farmers on the effectiveness of the dominant conservation techniques.
1.4 SIGNIFICANCE OF THE STUDY
Soil is the most important resource on which agriculture is based. Proper management of this valuable resource is vital to sustain long-term agricultural productivity. Unfortunately, soil erosion is usually only identified as a problem when channels cut through fields so deep that they restrict cultivation practices. The agrarian stagnation, plaguing food security in sub-Saharan Africa since the early 1970s, may
exacerbate with the projected climate change along with the attendant increase in risks of soil and environmental degradation.
Soil loss is not only a problem for the farmer, with the loss of organic matter and fertility, it is also an environmental problem. In fact, soil erosion occurs at unsustainable levels when small rills are recognizable in a field. Sediment entering streams can destroy fish habitat and water quality especially when soil particles contain contaminants such as pesticides or nutrients. Soil conservation techniques are therefore tools which the farmer can use to prevent soil degradation and build organic matter.
Research on soil conservation has been conducted for many years in Sub- Saharan Africa (e.g., Fournier, 1967; Greenland and Lal, 1977; Quansah, 1990; Kayombo and Mrema, 1998; Ehrenstein, 2002) and in Nigeria (Lal, 1976a; 1990). Initiatives have resulted in various so-called on-farm strategies including agronomic measures, soil management, and mechanical methods. However, studies of this nature specifically in Atiba Local Government Area with many farms found almost entirely in the villages, which constantly supply farm produce to the town residents, have been paid lesser attention.
1.5 RESEARCH QUESTION
- what are the soil conservation techniques adopted by farmers in the study area?;
- what are the most common techniques employed;?
- what are the reasons for their dominance and;?
- what is the perception of farmers on the effectiveness of the dominant conservation techniques?
1.6 SCOPE/LIMITATION OF STUDY
This work, therefore, sought to undertake a study to obtain information on the various on-farm soil conservation strategies in Atiba Local Government Area. The results of this analysis can then be used to provide initiatives for subsequent studies on this subject matter.