African Journal of Environmental Economics and Management Vol. 1 (1), pp. 013-021, August, 2013. Available online at www.internationalscholarsjournals.org © International Scholars Journals Full Length Research Paper Land use pattern and sustainability of food crop production in the fadama of Southern Guinea Savanna of Nigeria A. F. Lawal 1 *, O. A. Omotesho 2 , and M. O. Adewumi 2 1 Department of Agricultural Extension and Management, College of Agriculture, Mokwa Niger State, Nigeria. 2 Department of Agricultural Economics and Farm management, University of Ilorin, Kwara State, Nigeria. Accepted 2 April, 2013 An assessment of the sustainability of food crop production in the fadamas of Southern Guinea Savanna of Niger State, Nigeria was carried out within the framework of small-scale farming households utilizing fadama for the cultivation of food crops. The study determined profitability of food crop production in the fadama and identified the pattern of land use and management and its effects on sustainability of fadama. A two- stage simple random sampling technique was used to obtain 149 food crop farming households interviewed for the study. The data were analyzed by using descriptive statistics such as frequency distribution, mean, standard deviation, in addition estimates of crop diversification index (CDI), nutrient intake index (NII), Ruthberg index, farm budgeting model was made. A typical household hectared seventeen persons and planted an average of 3.44 ha scattered in three plots. The major enterprises were sole crop rice and maize – based mixtures in about 0.70 and 2.59 ha respectively. Estimated mean CDI was 0.651 implying stability of income and sustainability of mixed crop enterprises while mean NII was 1.89 showing that combined crops hectareve low tendency to deplete soil nutrient. The Ruthberg index value of 0.393 implied that a six years fallow period alone may not be adequate to restore natural fertility. The farm budget analysis showed thectaret the sampled fadama food crop farming household hectared positive net return for all enterprises. Maize/cowpea enterprise hectared the highest gross margin of N25, 663/ ha while leafy vegetables (for example spinach) hectared the highest return on investment (2.39). The average return on investment for all the farms studied was 1.89. Mixed cropping the dominant cropping system generally adopted by the fadama farming households gave higher gross margin per hectare. The study concluded that production of food crop in the fadama of the Guinea Savanna of Niger State, Nigeria is sustainable. Mixed cropping, consolidation of household resources, increased use of animal traction and organic fertilizer as well as integrated pest management is recommended. In order for the foregoing to be effective, they must be accompanied by improved extension service delivery, aggressive adult education programme, regulated use of agro-chemical, improved access to credit and availability of subsidized inputs. Keywords: Fadama, sustainability, mixed cropping, land use and management INTRODUCTION Background to the study Fadama are seasonally flooded plains along major rivers or depressions on adjacent low terraces. They are fertile, *Corresponding author. E-mail: funsolawal@yahoo.co.uk reduce the risk of crop failure and hectareve potentials for longer period of agricultural activities in a year. They pre-sent a unique opportunity towards reversing the declining per capita food production in Nigeria. However, develop-ment intervention, changing land tenureship and population pressure have been identified as threats to this valuable but delicate land resource The fadama size of Nigeria is estimated at about 4.6 million ha. Out of this, Niger State hectares an estimated 495,000 ha. This is second to Adamawa State with 625,000 ha, the largest in Lawal et al. 013 the country (Ingawa, 1998). If the potential of the inland valleys for intensive crop production could be realized, they might serve as a kind of safety valve for relieving pressure in other agro ecosystem particularly the humid forest and moist savanna (World Bank, 1992). Research problem The quest for harnessing the benefit of fadama land hectares ushered in technological innovations such as development of small irrigation pumps, small earthen dams and shallow tube wells. These hectares led to intensification in the use and management of fadama for agricultural activities. By and large, the inland valleys are cultivated by small holders whose land utilization and management with limited resources are aimed at achieving farm level objectives in terms of food security and economic viability. Their land use practices have a short term planning horizon with little attention to the status and management of agricultural land (Krusemen et al., 1996; Pannell and Glenn, 2000; Adewumi and Omotesho, 2002). Production objectives of short term food security and income that guarantees economic pro- duction by the farmer might be achieved. However, the achievement may hectareve come at the expense of long-term sustainability of land resources and develop- ment. Sustainable development is consistent with increasing environmental assets or development without destroying the future of natural capital stock. The most critical issue that this paper addresses is whether fadama land utilization is consistent with sustain- able development in view of some factors threatening sustainability around the fadama of Northern Nigeria. Kolawole (1991) reported that development intervention, changing land tenureship and population pressure were among the factors threatening sustainability of fadama in Nigeria. Lawal (2001) also reported that the construction of hydroelectricity Dams at Jebba and Shiroro hectareve hectared adverse effect on socio-economic lives of the riparian communities. This hectare led to the loss of crop and farm land to flooding as a result of flash-flood occasioned by opening of the dams. The potential of fadama area will remain elusive until the sustainability of this agro-ecosystem can be assessed which is the focus of this study. Therefore, some questions become fundamental in the assessment of fadama land use; Are the farming practices adequate to improve soil fertility, nutrient recycling and enhance sustainable production? (2) Can the present cropping practices enhance econo- mic benefits? (3) Is food crop production in the fadama sustainable? A work that assesses sustainability of food crop production in fadama at the small holder farm level is relevant in determining the extent to which the low external input agriculture (LEIA) farming households in the fadama allocate, use and manage this delicate land resource. The work is necessary to provide information to policy makers in assessing the economic rationale of different land management options in order to maintain the bio-physical condition of the land. It is against this background that the study on which this paper is based was undertaken. Objective of the study The objective of the study is to determine costs and return to food crop production in the fadama, identify the patterns of land use and evaluate its effects on the sustainability of fadama in food crop production in the Southern Guinea Savanna of Nigeria. Economic concept of sustainability The unpriced outputs of agricultural system both positive and negative have become of increased importance as compared with conventional marketed outputs. There is concern that, while technical changes have brought major benefits to consumers in terms of reduced food prices, some developments hectareve taken us into unsheltered waters. Nix (1990) pointed out that the idea of sustainability is central to attempts to define farm income. He quoted Hicks (1946) who defined income as that which could be consumed in a given period leaving the consumer as well off at the end of the period as at start. Recent theories of economic growth have built upon neoclassical foundation (Solow, 1992) and recognize that aggregate capital (K) consists of man made capital (Km), natural capital (Kn), human capital (Kh) and social capital (Ks), such that; K = Km + Kn + Kh + Ks (1) The quantity and quality of this capital determines the level of provision of utility for mankind on a year by year basis (Pearce, 1999). The notion of sustainability arises when it is required that the capacity of K to produce utility from one period to the next does not decline. Important modifiers to K include technological change, which may be regarded as endogenous or exogenous and popu- lation growth, which may hectareve positive or negative impacts on the component of capital (Webster, 1999). The distinction between weak sustainability and strong sustainability hinges upon whether substitution is permitted between the components of K. Weak sustain- ability implies that substitution may take place in order to maintain K. In other words, rates of substitution or elasticity’s are assumed to exist. In contrast, strong sustainability does not permit substitution between com- ponents of K and the emphasis is placed on conserving Kn (and each of its separate sub-components) at all costs. Arguments for such an approach include irreversi- 014 Afr. J. Environ. Econ. Manage. bility of some changes in natural capital for example species extinction (Tversky and Kahneman, 1981). It is further argued that natural capital is impossible to value by whatever means and that no trade-offs could be made within Kn or any level of subdivision of Kn. However, Vander Hectaremsfort and Latacz-Lohnman (1998) have argued for strong sustainability on the basis of the second law of thermodynamics (the entropy law), which implies a limit to the stock of energy available to mankind for transforming low entropy natural capital through manufactured capital to high entropy waste products. It is argued that that Km and Kn should be complements rather than substitutes. METHODOLOGY Area of study The study was carried out in the fadama areas of Niger State, in the Southern Guinea Savanna of Nigeria. The fadama along river Niger and river Kaduna and other minor rivers and floodable plains in Niger State were used for the study. Niger State lies between longitude 8°11’ and 11°20’ north of the equator and between 4°30’ east of the equator. It covers an estimated land area of 4240 km sq. The vegetation of the state is mainly Southern Guinea Savanna. The mean annual rainfall ranges between 1110 mm in the north and 1600 mm in the south. The average annual number of raining days ranges between 187 and 220 days. The rain starts in late April and ends in October with the peak being in July. The average minimum temperature is about 26°C while the average maximum temperature is about 36°C. The mean humidity ranges between 60 (January to February) and 80% (June to September). The vege-tation supports the cultivation of root crops and grains. The predominant crops are; rice, sorghum, millet, yam, groundnut and cotton. Method of data collection Data used for this study were from both primary and secondary sources. The relevant primary data were obtained through a farm management survey of fadama food crops farming households conducted between August 2004 and September 2005. The main instrument for data collection was structured interview schedule. These were administered on head of fadama food crop farming households by trained enumerators under the supervision of the researcher. The data covers farming activities for the 2004 cropping season. Data collected covers information on fadama food crop farming households head characteristics (age, level of education, family size etc), land use and management practices, input and output data, as well as their prices, crop combination and diversification etc. Sampling procedure The target population for this study is the fadama food crops farming households in Niger State, Southern Guinea Savanna, Nigeria. A two stage simple random sampling technique was used to select sample for the study. The first stage involved the random selection of fadama farming villages in the three ADP zones of the State. The 1991 fadama village and households listing of Niger State Agricultural Development Project (NSADP) served as the sampling frame for the selections. About five percent of the total fadama farming villages were randomly selected for the study. The second stage of sampling involved the random selection of fadama farming households. About 10% of the fadama farming households in each of the selected villages were sampled for the study. The villages and households selection was based on the proportion of fadama food crop farming households in the NSADP zones and the villages respectively. A cross sectional data from 149 fadama food crop farming households were collected for study. Analytical Techniques Combinations of analytical techniques were employed in this study. Descriptive statistics such as mean, standard deviation, frequency distribution were used to capture the socio economics characte- ristics and pattern of land use management. In addition to descriptive statistics the following indices were calculated to further investigate the influence of pattern of land use and management on sustainability of fadama land. Crop diversification index (CDI) Stability of yield and revenue from crop planted are indicators of sustainable farm practice, this was captured with crop diversification index. The crop diversification variable was measured in this study by the Herfidahl index given as; n 2 CDIj = (1) Pi j i 1 Where; CD1j is the crop diversification index for the j th household. PiJ = Proportion of total income from each crop in a particular enterprise. A value approaching 1.0 indicates specialization whereas smaller values reflect increasing diversification, stability of income and sustainability of land use pattern (Spio, 1996; Udoh, 2000). Nutrient intake index (NII). Following Udoh (2000) the NII was estimated to reflect how crop diversity pattern can affect nutrient depletion and sustainability of farmland. This was measured as a ratio of crop configuration to number of crops in combination. Crop configuration was derived by assigning different weights to different classes of crop in com- bination and summing the weighted value for each farm and then dividing the value by the number of crops in such combination. The assigned weights to the respective classes were based on nutrient depletion ability of crops in an environment where nutrient augmenting input like fertilizer is inadequate (Fageria and Baligar, 1993). It is expected that the yield of crops in combination would be affected if the combined crops were mostly of the same class of crops. For instance, a combination of melon/maize/yam would not deplete soil nutrient as the case of cassava/yam/cocoyam mixture. Therefore, combining crops that would deplete soil nutrients heavily do not show sustainable land use practice. The Nutrient Intake Index is given as NIIj = ΣWi i = (2 ----, n) N i = (2 ----, n) (2) Where; NIIj = Nutrient intake index for j th households. n = Number of crop in combination wi = Particular weight attached to type of class of crop planted (legume = 1, vegetable/cereal = 2, Root tuber = 3, stem tuber = 4) Lawal et al. 015 Nutrient Intake Index is meant to capture the vulnerability of farm total output to different crop combination. The index value ranges between 1 and 4. The higher the NII the more the likelihood that crop combinations can affect nutrient depletion, land degradation and sustainability of farmland (Fageria and Baligar, 1993; Ali, 1996; Udoh, 2000). Ruthenberg -value The Ruthberg -Value shows the land use intensity for an area. It shows if the length of fallow may be adequate for soils to restore natural fertility. It is given as; R – value = c c+f (3) Where; c = Number of cropping years. This was obtained as the average number of years a land was used before fallow. f = Number of fallow years. This was obtained as average number of years a land was allowed to fallow before further cultivation. R – Value = 1 for permanent cultivation. The further the value is from one the more the likelihood that fallow would be adequate to restore natural fertility and improve sustainability (Udoh, 2000). Degrees of soil erosion, flooding and drainage were also part of variables used to measure extent of likely land degradation, the level of nutrient depletion and fadama sustainability. Farm budget model Olukosi et al. (2006) stated that farm budget is a detailed physical and financial plan for operation of a farm for a certain period. Farm budget model enables the estimation of the total expenses (costs) as well as various receipts (revenue or returns) within a production period. Musa et al. (2006) stated that thectaret farm budget model gives a measure of profitability. Following Olukosi and Erhectarebor (1988), farm budget was estimated on per hectare basis in this study and specified as NFI = GI - TVC - TF (4) GM = GI - VC (5) Where; NFI= Net farm income, GM= Gross Margin per Hectare. The fixed inputs used during the survey consist of inputs such as baskets, hoes, cutlasses and rain boot. The depreciated values of these assets were negligible, therefore GM/ha was used for profitability analysis. GM/ha was calculated for all the enterprises that the fadama farming households were engaged in during the survey period. GM allowed for comparison of the profit of the different enterprises cropped by the sampled households during the survey. Return on a Naira Investment (RNI) which provides a measure of economic performance of each enterprise in terms of revenue accruing to the households and cost of inputs employed was determined as; Return on a Naira Investment (RNI) = GI TVC (6) RNI > 1 for enterprise to be sustainable (Alamu and Coker, 2005). Return on a Naira Investment was used to rank the enterprises of the sampled fadama food crop farming household. RESULTS AND DISCUSSION This section presents the results of the analysis of data collected and discussion on it. SOCIO-ECONOMIC CHARACTERISTICS OF FADAMA FOOD CROPS FARM HOUSEHOLD HEADS Table 1 shows the summary of farm inputs and socio- economics characteristics of fadama food crop farming households during the 2004 cropping season. On the average the farm size cultivated was 3.44 ha in about 3 plots. Hired labour was about 32% of total labour used for production. One of the probable reasons for hiring little labour could be the fact that an average fadama farming household head is still young (about 44 years), active and married with about 17 family members who provided the needed manpower for farm operations. On the average, the cost of labour used constitutes about 73.17% of total expenditure on farm inputs. This phenomenon clearly demonstrates the dominance of labour in food crop production in the fadama area. Labour is the most important factor of production because farming activities in the area are mostly labour intensive. Table 2 reveals that an average household head was about 44 years, males (97.32) and married (98%) with a household size of 17 persons. An appreciable high level of literacy was recorded among household heads (54%). They are likely to hectare good potentials to acquire and interpret messages relating to their farming operation. The mean fadama farming experience was about 17.5 years. About 59.06% of the sampled farming households hectared no extensions contact. The mean extension contact was 1.5 visits per household per annum. ANALYSIS OF CROPPING PATTERN AND INDEX OF DIVERSITY Land use pattern The study reveals that the fadama farming household adopted different agricultural diversification strategies to fully utilize the fadama land and cope with risks and uncertainties. The strategies include: (i) An act of cultivating flood tolerant crop such as rice and sugarcane during the early wet season (ii) Cultivation of drought resistant crops: millet, cowpea, sorghum, cassava later in the season at the drier part of fadama area. (iii) Cultivation of crops with short gestation period: Okra, leafy vegetable, late sorghum and cowpea to utilize moist land during the early part of dry season. These strategies assure adequate utilization of the fadama land, which satisfy the food security and income generation objectives of the households. Tables 3 and 4 reveals that mixed cropping was the 016 Afr. J. Environ. Econ. Manage. Table 1. Summary Statistics of Farm Inputs and Socio-economic Characteristics of Average Fadama Food Crop Farming Household. Description Sample mean Standard deviation Minimum value Maximum value Farm size (Hectare) 3.44 2.68 0.10 6.30 Number of plots 3.00 9.56 1.00 6.00 Family labour (man-days) 118.74 38.99 7.00 220.00 Hired labour (man-day) 55.71 11.63 2.00 70.00 Family labour (N) 32,524.00 43.68 37.00 290.00 Hired labour (N) 15,320.00 37.80 1750.00 55,000.00 Total labour 47,845.00 218.54 50.00 17,500.00 Pesticide (litres) 1.84 1.57 0.00 7.00 Pesticide (N) 2,870.00 53.43 9250.00 72,500.00 Capital (N) 2,275.00 9.53 0.00 12,000.00 Fertilizer (kg) 78.00 2.76 0.00 8.00 Fertilizer (N) 3,978.00 2.76 850.00 9,000.00 Other operating cost (N) 6,624.00 204.30 0.00 38,500.00 Age(years) 44..50 11.52 21.00 68.00 Household size(No of people) 17.00 9.65 1.00 32.00 Fadama farming experience(yrs) 17..50 8.65 6.00 45.00 Extension contact (No of visits/yrs) 1.50 1.35 0.00 12.00 Credit ( N) 3,250.00 192.40 0.00 35,500.00 * Hired labour cost average N275 per man-day during the survey. Source: Field Survey, (2004/2005) Table 2. Demographic characteristics of the fadama food crops farming household. Characteristics Frequency Percentage (i) Gender Male 145 97.32 Female 4 2.68 Total 149 100.00 (ii) Age group 20 - 50 125 83.89 >51 Total 24 16.11 (iii) Highest educational level 149 100.00 No formal education 17 11.41 Quranic 54 34.89 Adult 24 16.11 Primary 43 28.86 Secondary 9 6.04 Tertiary 3 2.01 Total 149 100.00 (iv) Household size 1 - 5 15 10.07 6 - 10 27 18.12 11 - 15 42 28.18 16 - 20 51 34.23 21 - 25 9 6.04 > 26 5 3.36 Table 2. Contd. Total 149 100.00 Source of seed Personal Stock 88 59.06 Local market 33 22.15 ADP and other agencies. 28 18.79 Total 149 100.00 (vi) Experience in years 0 - 5 11 7.38 6 - 10 23 15.44 11 - 15 51 14.22 16 - 20 33 22.15 21 - 25 13 18.13 26 - 30 9 6.04 > 31 9 6.04 Total 149 100.00 Source of credit No credit 99 66.44 Family and friend 30 20.13 Money lenders 9 6.05 Cooperative society 7 4.70 Community bank 4 2.68 Total 149 100.00 ii) No of extension visits. 0 88 59.06 1 - 2 22 14.76 3 - 5 18 12.08 6 - 8 16 10.74 9 - 11 - - > 12 5 3.36 Total 149 100.00 Source: Field survey, (2004/2005) most common farming system. The sampled households cultivated thirteen (13) types of crops as sole enterprises and eleven (11) types of mixed crops enterprises during the survey. 209. 11 ha (36.70%) and 360.72 ha (63.30%) of the cultivated land area during the survey were used for sole crop enterprises and mixed crops enterprises respectively. Results show that farming households use more of their own stock of local varieties, which inherently possess low yield potentials as planting material. Rice is the dominant and most preferred crop planted as sole crop, it was the only crop planted by all the sampled households. It was planted in 17.14% (104.3 Ha) of the land area utilized for crops production during the survey. Maize/cowpea mixture was the most preferred enter- prises among the mixed crop farms accounting for 10.36% (63.05 ha) of the total area cultivated by sampled households. The cropping pattern clearly reveals pre- ference for rice, maize, sorghum, yam and cowpea as the most important food crops grown by the households. Under crops combination, cowpea is the predominant second crop grown in association with cereal crop such as maize and sorghum. This result is similar to that of Amaza (2000) which reported mixed cropping as the dominant cropping system of farmers in Gombe State of Nigeria. Index of crop diversification The pattern of land use as regards stability of yield and revenue from crops planted are indicators of sustainable farm practice (Webster, 1999). This is measured with the Lawal et al. 017 018 Afr. J. Environ. Econ. Manage. Table 3. Distribution of area cultivated (ha) to sole crop enterprises. No of Area cultivated % of Area cultivated Mean area Minimum area Maximu Households (Ha) cultivated (Ha) cultivated (Ha) cultivate Cowpea 8 6.4 1.12 0.80 0.20 3.0 Groundnut 8 16.00 2.81 2.00 0.50 2.5 Maize 10 22.30 3.91 2.23 0.80 3.5 Okra 12 7.20 1.26 0.60 0.20 2.0 Onion 2 1.50 0.26 0.75 0.50 1.0 Pepper 6 4.80 0.84 0.80 0.20 3.5 Rice 149 104.3 18.32 0.70 0.30 4.5 Sugarcane 7 5.6 0.98 0.80 0.30 3.0 Sorghum 5 8.25 1.45 1.65 0.60 2.8 Soybean 3 3.00 0.53 1.00 0.50 1.5 Tomato 14 11.90 2.09 0.85 0.30 1.7 Vegetables 14 12.46 2.19 0.89 0.25 1.0 Yam 6 5.40 0.95 0.90 0.50 1.5 244 209.11 36. 70 0.86 Source: Field Survey, (2004/2005). Table 4. Distribution of area cultivated (Ha) to mixed crop enterprises. Enterprise No of households Area of land %of Area of Mean area Minimum area Ma cultivated (ha) land cultivated cropped(Ha) cropped (Ha) cr Maize/sorghum 29 30.72 5. 39 1.28 0.20 Mellon/maize/sorghum 28 46.94 8.24 1.68 1.0 Maize/sorghum/cowpea 36 66.96 11.75 1.86 1.0 G/nut/sorghum/cowpea 12 16.80 2. 95 1.40 0.5 Sorghum/cowpea 29 43.84 7. 69 1.56 0.2 Sorghum/Bambara 1 1.30 0. 23 1.30 1.30 Maize/cowpea 58 71.34 12. 52 1.23 0.5 Maize/cassava 10 8.64 1. 52 0.86 0.4 Maize/yam 32 27.52 4.83 0.86 0.3 Millet/groundnut 20 28.20 4. 95 1.41 1.0 Millet/cowpea 13 18.46 3. 24 1.42 0.6 263 360.72 63.30 1.37 Source: Field Survey, (2004/2005). Table 5. Herfidahl index of crop diversification Description of cropping pattern Mean Herfidahl index SD Minimum value Maximum value CV % Sole 1 1 1 1 100 Two-crops combination 0.625 0.189 0.384 0.946 30 Three-crops combination 0.462 0.106 0.264 0.753 23 Whole farm 0.651 0.302 0.264 1 47 Source: Field survey, (2004/2005). indices of crop diversification. The index used in this study is Herfidahl index. This is modeled in terms of proportion of net income from the various crops in each combination (see equation 1). Table 5 shows that the estimated mean diversification index was 0.651. This implies increasing diversification among majority of fadama food crops farming households which could ensure stability of yield, income and sustain- ability of fadama land. These crop combinations could be regarded as environmentally and economically sound practice. It is environmentally friendly because when two or more crops are planted under low use of land augmenting material like fertilizers as observed during the survey, the negative effect of such material on the environment is reduced. The cultivated crop depended mostly on the available soil nutrient for their growth and development. Each crop uses the fertility of the soil in its own peculiar way especially when the rooting systems of the crops differ. Mixed cropping planted this way during the survey generally gives more revenue and higher gross margin per hectare than mono cropping. This finding is similar to the work of Spio (1996); Alamu and Coker (2005) who reported thectaret mixed cropping in Ghana and Nigeria gave higher yields and revenue per hectare respectively. Index of soil nutrient intake To achieve the maximum advantage of inter cropping or mixed cropping, combined crops must be grown in such a way that each crop in mixture uses the nutrient of the soil in different ways as to eliminate the risk of competition for the available soil nutrients. Table 6 shows the distribution of the fadama farming households based on how their crop diversity pattern can affect nutrient depletion and sustainability of farmland. This was calculated using equation 2. The mean Nutrient intake Index (NII) was 1.89. This index measured the intensity of likely nutrient depletion by the combined crop. This result implies that the com- bined crops hectareve very low tendency to deplete soil nutrient. These may not be unconnected to the fact that eight (8) of the crop combinations hectared a leguminous crop in addition to the cereal in the combination. So the cropping pattern is such thectaret could not adversely affect soil nutrient and crop nutrition. These could trans- Table 6. Distribution of nutrient intake index among sampled households. Nutrient Intake index Frequency Percentage 1 - 1.5 23 15.44 1.6 - 2.0 99 66.44 2.1 - 2.5 27 18.12 Total 149 100 Source: Field survey, (2004/2005). These could translate to consistently good yield of fadama farm land which is an indication of sustainability of the cropping pattern of the fadama food crops farming households. Udoh (2000) reported NII of 3.25 among farmers in eastern Nigeria, most of these farmers planted root/tuber crops in combination with other crops. Ruthberg- value The Ruthberg-Value shows the land use intensity for the sampled households. It was estimated as 0.983 during the survey. This implies thectaret cultivation is nearly on a continuous basis in the fadama. These may not be unconnected with the high value attached to the fertility of fadama and probably the difficulty in land clearing. Depending on the agronomic practices adopted by the households, the land use may be unsustainable. About 65% of the farms sampled hectared different levels of soil erosion symptoms indicating incidence of soil degra- dation and subsequent nutrient loss. The farmlands were not adequately covered with crop canopies. In the long run, without adequate remedial and preventive measures, soil fertility may be affected which could affect the sustainability of fadama land of Niger State in Nigerian Southern Guinea Savanna. Cost and returns in food crop production in fadama of Southern Guinea Savanna of Niger State, Nigeria. From the results in Table 7, the production cost and revenue per hectare varies across the households and it did not necessarily depend on the type of crop planted in the enterprises. Gross margin analysis shows thectaret maize/cowpea enterprise with N25, 663/ha hectares the Lawal et al. 019 020 Afr. J. Environ. Econ. Manage. Table 7. Gross margin per hectare by enterprises for food crops planted by sampled fadama farming Households. Enterprises Mean farm Mean variable Gross margin Ranked based Return on Revenue/ha cost per hectare per hectare on GM//ha naira investment r Maize/Cowpea 57,500 31,837 25,663 1st 1.81 Sorghum/Cowpea 40,100. 17,886 22,214 2nd 2.25 Maize//sorghum/Cowpea 42,700 22,122 20,578 3rd 1.85 Maize / Yam 56,250 36,684 19,566 4th 1.53 Sugarcane 41,250 27,550 18,700 5th 1.68 Sorghum / Bambara 35,600 17,850 17,550 6th 1.89 Millet /Cowpea 36,400 19,750 16,650 7th 1.84 Soybean 41,593 24,946 16,627 8th 1.57 G/Nut / Sorghum Cowpea 39,700 23,283 16,417 9th 1.71 Okra 28,850 12,502 15,950 10 th 2..30 Mellon / Maize /Cowpea 36,585 20,670 15,915 11 th 1.73 Maize / Cassava 39,600 23,755 15,845 12 th 1.68 Maize / Sorghum 38,631 22,2716 15,684 13 th 1.61 Rice 50,600 25,650 14,950 14 th 1.42 Yam 34,200 19,461 14,739 15 th 1.76 Pepper 32,487 18,195 14,292 16 th 1.79 Sorghum 31,767 17,413 14,267 17 th 1..82 Tomatoes 28,850 14,650 13,850 18 th 1..95 Cowpea 31,500 17,685 13,815 19 th 1.78 Millet /G/nut 28,300 14,595 13,705 20 th 1.94 Vegetables 23,500 9,850 13,650 21 st 2.39 Maize 29,592 16.250 13,342 22 nd 1.70 Onion 21,600 14,000 7,660 23 rd 1.54 Bambara 14412 8,461 5,951 24 th 1.70 Whole farm 33, 623 18, 486 15, 137 1.89 Source: Field survey, (2004/2006). highest GM/ha during the survey. Based on the profitability ratio leafy vegetable (spinach), okra and sorghum/cowpea ranked first, second and third respectively. These enterprises returns N2.39k, N2.30k and N2.25k on every N1 invested in the enterprises respectively. The average gross margin per hectare for a representative farm was N 15,137 while average net farm-income was Conclusion N 52, 071. The average return on a Naira invest- ment ratio for all farms was 1.89 showing thec- The general co taret on financial consideration the farm operation that production of food crop farming households in the Fadama of Niger State, Ni Southern Guinea Savanna, Niger State, Nigeria crop enterprises was profitable and therefore sustainable. farm income, pr Lawal et al. 021 investment ratio than is greater than one. The levels of diversification of the enterprises do not impact negatively on the nutrient intake index (NII) of the crops. The Ruthberg index value, erosion and drainage situation shows thectaret remedial and preventive measure is required to ensure sustainability of fadama land in the Southern Guinea Savanna of Niger State, Nigeria. Recommendations Government should provide adequate and assessable inputs such as work oxen, improve seeds, herbicides and fertilizers to fadama food crop farming households. The inputs should be provided at subsidized rate to encou- rage their usage. Vigorous effort should also be made to encourage the farm households to employ animal traction involving oxen or camel with appropriate implements. The use of improved seeds varieties with high yield potentials together with packages of required crop husbandry is also recommended. Extension workers should be pro- perly motivated through provision of appropriate vehicle for their movement and prompt payment of their salary and allowances. 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