Household size and agricultural land-use pattern in Obagaji area of the Guinea Savanna region, Nigeria

In the past two decades, population-environment research has focused on the hypothesis that house hold population has significant influence on agricultural land-use patterns and the health of the environment. This study is therefore aimed at providing land use planners in Nigeria with basic data and information that will be useful in identifying the prospects for and constraints to intensive cultivation systems in Obagaji area. The simple random sampling technique, using the table of random digits and availability sampling method were respectively employed to select settlements and farmers for investigations. Structured interview was utilized to generate data for the study. In order to capture the inputs to land in the study area, the level of agricultural land-use intensity was measured, using three surrogates, namely, proportion of farmland cultivated, frequency of cultivation and crop combination level. The study results showed that Obagaji area is a mixed cropping region where semi permanent cultivation with rotational bush fallow system dominates the existing cultivation systems. The characteristic features of agricultural practices in households with low number of family members in the area are: more extensive land-use systems, more of shifting elements than permanent cultivation, only very small proportion of land is under cultivation at any one time and very short cropping period on the field. The reverse is true for households with high number of family members. The direct variation in intensity of agricultural land use with regards to family size in the area is significant.


INTRODUCTION
Human population and natural environment research in the past two decades has focused on household level population dynamics and their relationships, through livelihood strategies, to environmental change, particularly in the rural areas of developing countries.In agriculture, research is fast shifting to the relationship between household size and agricultural intensification processes (Zimmerer, 2004).The focus on micro demographic dynamics of rural small land holders is based on the recognition that they are important players in natural resource use and landscape change.It has been argued that the house hold population has significant influence on cropping systems and practices (Uzeh et al., 2008).The focus has been on the relationship between farm labour and agriculture production as well as farm labour and agricultural land use pattern in relation to individual farm family rather than the absolute regional or national population density.Their opinion is premised on Boserup (1965)'s hypothesis that population growth leads to an increase in agricultural intensification; and rooted in Malthus assumption that increase in population could facilitate a greater competition for land resources that could lead to diminishing return (declining marginal or unit output) or outright resource shortage.
In Nigerian agriculture, manual labour still predominates E-mail: adikwujames1959@gmail.com.Tel: 08057427652.from tillage to harvesting and processing.Family members provide the potential labour for agricultural intensification (Okafor and Onokerhoraye, 1986;Adeniyi, 1990).According to Okafor (2001), lack of farm labour due to urbanization, among others, holds back production in the nation.Mortimore (1993) and Eboh (1994) espoused that population pressure at the family level was found to be a significant determinant of agricultural land use patterns in Nigeria; especially in land fragmentation.
The authors further described that the level of agricultural land-use intensity increases as pressure increases, the reverse is also true in rural agriculture.However, there are no such scientific studies based on agricultural landuse systems in Obagaji area.This has constricted the understanding of agricultural land-use pattern, in particular, with regards to household size in the study area.The urgent and pressing need for proper understanding of the relationship between family size and agricultural land use pattern to achieve sustainable rural land use planning in Obagaji area is the reason for the study.The specific objective is to evaluate the strength of the relationship between household size and cropping systems and practices in the area.

MATERIALS AND METHODS
Obagaji area (36900 h) lies between latitudes 7°51′N and 7°56′N and longitudes 7°52′E and 7°56′E (Figure 1).The main relief divisions of the area are flood and high plains.Ferrasols and Hydromorphic are the major soil types in the region.The climate here is 'Aw' climate type, Koppen's classification with mixed leguminous wooded tropical guinea savanna vegetation.Primary data were taken from farmers about their households and their farming system.A total of 500 individual farmers were interviewed to get the relevant information.Structured interview schedule was administered to get information on duration of crop-fallow cycle and types of agricultural land use in each of the nine farming regions (Anankpa, Eji, Gomenti, Ikpele, Odu, Ohebitele, Okpobe/Ahe, Okpopi and Okwu) in the study area.The farmers were chosen along bush paths radiating from the centre of the settlement to the farming regions.In order to capture the inputs to land in the study area, the level of agricultural land-use intensity (the amount of input per unit area; (Found, 1971;Dietrich et al., 2010) was measured; using three surrogates, namely, proportion of farmland cultivated, frequency of cultivation and crop combination level, all expressed in percentage.In other words, agricultural land-use intensity was determined using the following mathematical model developed based on the ideas of Turner II et al. (1977) and Singh and Dhillon (2004): Where I = level of agricultural land-use intensity, 100 = percentile, N = number of variables in use GAC = gross area cropped, TLA = total land area belonging to farm family, C =cropping phase, F = fallow phase, ONC = observed crop combination number on a plot in a growing season and ENC = expected crop combination number on a plot in a growing season.'Intensive' or 'highly intensive' land use occurs when a large quantity of inputs per unit area is used.
Following Robinson (1998) linear regression was used in the relationship between family size and agricultural landuse intensity.The equation of the least squares was first determined and then plotted.The mathematical model is as follows:

RESULTS AND DISCUSSION
Farmers in Obagaji area practice three main cropping systems: inter cropping, inter planting and sole cropping (Table 1).Inter cropping (the planting of quick growing and quick maturing crops between slow growing and slow maturing crops, for example, groundnut and guinea corn) was found to be the most common cropping system, as nearly 60% of the total fields sampled it was found practicing it.Mono cropping (the practice of growing exclusively one type of annual crop and harvesting it before planting another crop on the same piece of land) and inter planting (the growing of a main crop between another main crop, both of which are slow growing and maturing, for example, yam and cassava) were observed on the remaining fields in about equal proportions.Inter cropping and inter planting were practiced chiefly to maximize the use of the limited growing season.The information presented on Tables 2 to 5 has shown that family size influenced the proportion of family farmland cultivated, frequency of cultivation, crop combination pattern and intensity of agricultural land use in Obagaji area.The family land cultivation increased as the number of family member increased and vice versa.Farm families with over 10 people cultivated close to 80% of their family farmland, the figure decreased to nearly 60% for families of 6 to 10 people, but just over 50% for families of 1 to 5 people.Similarly, the mean frequency of cultivation of fields' varied directly with family size.Families of more than 10 people had moderate frequency of cultivation (6 years duration of crop/fallow cycle) while families of 1 to 10 people had low frequency of cultivation (7 years duration of crop/fallow cycle).What was observed in this area was that farm families which have much farmland per person could afford to leave large proportion of such land in long fallow and vice versa.The families of more than 11 members practice 4 crop combinations; the figure is 3 and 2 for 6 to 10 and 1 to 5 people respectively.The main reason of farmers for such situation was to cope with the food and financial needs of the family.The level of agricultural landuse intensity on farmland of families of over 10 people was 60%.The figure was less than 50% for families of 1 to 9 people.The results of the application of linear regression analysis to agricultural land use intensity presented on Figure 2 indicates that the level of agricultural land-use intensity possess positive slope.The coefficient of variation is 0.746855 (74.69%).This indicates that the variation is significant.The direct variations in agricultural land-use intensity in relation to family size in the study area is a similitude of the results obtained in India where increase in number of family members led to general increase in agricultural land use intensity (Sinch, 1978) and Zaria Province of the then North Central State of Nigeria (Norman, 1990).

Conclusion
The agricultural practices in Obagaji area were found to be dominated by mixed cropping region where semi permanent cultivation with rotational bush fallow system dominated the existing cultivation systems.Some of the characteristic
the intercept; b the slope (regression coefficient); x the farm size in hectares; y the agricultural land-use intensity values; x the mean family size and y the mean agricultural land-use intensity and n = number of distributions.The regression analysis was employed to evaluate the land use intensity variability with family size.The strength of the relationship was determined using the coefficient of determination or r 2

Table 2 .
Family size and farm size cultivated.

Table 3 .
Family size and frequency of cultivation.

Table 4 .
Family size, crop combination and number of field.features of agricultural practices in households with low number of family members in the area were: (i) more extensive land-use systems because the available land was abundant, (ii) more of shifting elements than permanent cultivation because of less pressure on land, (iii) only very small proportion of land was under cultivation at any one time and very short cropping period on the field.The reverse was true for households with large family size.The level of agricultural land-use intensity in this area was moderately high with strong inverse variation