1. Introduction
Agriculture production in Senegal is dominated by staple food crops including, pearl millet (
Pennisetum glaucum; 38%), cowpea (
Vigna unguiculata; 24%), maize (
Zea mays; 20%), rice (
Oryza sativa; 9%), and sorghum (
Sorghum bicolor; 9%) which are mainly grown in the rainy season [
1]. Groundnut or peanut (
Arachis hypogaea) is important both in terms of volume of production and area harvested but is mainly market-oriented for local industries or export. Faced with growing food and nutritional needs of a population of more than 14 million, with projections to increase to 19 million in 2030 and 26 million by 2050 [
2], increasing agricultural production to meet food demand is an important challenge.
Cowpea plays a significant role in food and feed, supplying a needed protein source [
3], and generating income for Senegalese rural households. Cowpea is among the most cultivated grain legumes with important nutritional, economic, and cultural significance in semi-arid regions of west Africa [
4]. In regions of low rainfall or delayed cropping season, farmers rely on cowpea because of the short production cycle and drought tolerance [
5]. In normal growing seasons, the availability of cowpea green pods in early September provides food at a time of the year when granaries are almost empty. Cowpea marketing is an opportunity to generate income for smallholder producers. With food production lagging behind population growth and demand for livestock products booming due to rapid urbanization and climate change, cowpea cultivation is very valuable. Cowpea leaves and stems have high protein content and serve as nutritious fodder for cattle and other farm animals and its roots provide nitrogen to improve soil fertility.
Cowpea is a short duration crop well adapted to the erratic rainfall, extreme heat, and nutrient-deficient soils that prevail in semi-arid environments in west Africa. In Senegal, cowpea is grown in all agro-ecological zones, particularly in the north-central region of the peanut basin, which covers an average of 82% of the sown area and 80% of national production [
6]. However, its role in rural households is affected by low productivity and the limited availability of fodder to support livestock, especially during the dry season. New cowpea varieties of dual-use offer both the ability to achieve greater grain yields for human consumption and high-quality fodder for animal production. Therefore, the adoption and scaling up of dual-use cowpea varieties has become very important with the aim of increasing rural incomes and supporting human food security and livestock production systems.
Since the 1980s, most research on the cowpea sector in Senegal has focused on the determinants of cowpea yield [
7], adoption determinants of improved varieties, and market information systems [
5]. Few studies have attempted to identify constraints to adoption in other semi-arid environments in West Africa [
8,
9] and in other parts of Africa [
10,
11]. Moreover, in the identification of new varieties’ adoption determinants, the context of cropping system used in cowpea production is usually not considered. Notwithstanding the importance of socio-economic characteristics and access to information, cropping system including the choice of crop associations, the use of chemical and/or organic fertilizers, and the preference of farmers towards the production of fodder for animal feed or grain for marketing and income generation, improve the understanding of factors likely to influence adoption of new crop varieties. This study investigated the effect of socio-economic conditions and production choices of farmers on the adoption of new cowpea varieties to improve human food and animal fodder in Senegal. The specific objective was (i) to analyze the socio-economic characteristics of cowpea production systems and (ii) determine the profile of new cowpea varieties adopters in the Senegalese peanut basin through descriptive analysis and econometric analysis to see whether socio-economic conditions and production choices influence new cow variety adoption.
2. Materials and Methods
2.1. Study Area
The study was conducted in the peanut basin of Senegal, which covers the west and the center of the country, corresponding to the administrative regions of Louga, Kaolack, Fatick, Thies, Diourbel, and Kaffrine (
Figure 1). It covers a third of the land area of Senegal, home to about half of the population, and is characterized by tropical ferruginous soils. Major agricultural crops grown are mainly dry cereals (i.e., millet and sorghum) and legumes (i.e., groundnut and cowpea). Three of the six regions of the peanut basin were chosen for the study based on annual rainfall amounts [Louga (arid), Diourbel (semi-arid) and Kaffrine (semi-humid)] and the acreage and importance of cowpea production. In each of the three regions, a study area was selected based on cowpea acreage produced. The selected study areas included Bambey in the Diourbel region, Kebemer in the Louga region, and Kaffrine in the Kaffrine region (
Figure 1).
2.2. Sampling of Sites, Villages, and Targeted Population
We used a three-stage sampling procedure to select first, the communes, then the villages, and finally the agricultural households for the study. The objective of the selection was to balance the number of villages and communes chosen in each region, minimize the effects of sampling error or bias resulting from the proximity of the villages, and constitute a group of beneficiaries and control for the impact assessment study. Thus, 10 villages were randomly selected in each of the study regions at Bambey, Kebemer and Kaffrine. Climate type, average rainfall, and temperature, in each of the three study regions are indicated in
Table 1. In each village, random sampling was conducted to select eight heads of agricultural households. In total, the questionnaire was administered to 240 selected farmers in three regions, seven communes, and 30 villages.
2.3. Questionnaire
A baseline survey was conducted in the three study regions between April and May 2021. The questionnaire used for data collection consists of fourteen sections (see
Supplementary Materials, with only relevant sections of questionnaire for this specific study). The first section had information on the identification of the household, and collected information on geographical, communal, and regional location. The next information collected was on the characteristics of the head of household including age, gender, marital status, type and level of education and experience. Characteristics of the household included information on composition, the cultural practice, sources of income and level of food security. The third section focused on farmland owned by the household, their location in relation to the family concession, method of acquisition, land tenure, farm size, cropping system practices and person responsible for decision-making. The fourth section collected information on cowpea production system by focusing on the methods used for each farming operation ranging from soil preparation, planting, harvesting and post-harvest operations. This section also covered aspects of labor mobilized in cowpea production as well as types of cowpea varieties and inputs used.
The fifth section requested information on contracts between producers and traders while the sixth section focused on the production tools used in the fields. Information on the quantity of crops produced and the distribution was the next subject covered in the seventh section before information on pest, diseases, storage methods and participation in demonstration field trials. Information on access to financial and extension services was collected in the next section before the approaches used for cowpea marketing were studied. Data was also collected on a role of livestock in the generation of household income.
2.4. Methodology for Data Analysis
To understand the constraints to new cowpea varieties adoption, we combined a descriptive statistical analysis with a Probit model to analyze the data collected from the survey. The descriptive analysis of the responses from the questionnaire was conducted on household characteristics, cowpea use and productivity, and use of improved varieties. The data collected were disaggregated and analyzed according to the agro-ecological zone and averaged when generalization was needed for the entire study. STATA software summarize commands were used to obtain average, standard deviation, minimum and maximum for quantitative data analysis by region. However, for qualitative data, the table command of STATA version 14 software generated proportions of modalities crossed with regions. Graphs and charts were developed using a sigma plot (Systat Software Inc., Palo Alto, CA, USA).
First, the characteristics of the head of household (CHH), including age, sex, marital status, and level of education, were analyzed for each of the three agro ecological zones. For a CHH with a continuous variable (i.e., age), average site CHH was calculated as the sum of the ages of the head of household from each individual respondent at the site divided by the total number of respondents (Equation (1)). Across regions, the average was calculated as the sum of the average CHH of each of the three regions divided by three.
X = individual respondent, n = total number of respondents, and HH = head of household.
For CHH with discrete values (like gender, marital status, level of education), The percent CHH of each region was calculated as the total count of similar characteristic responses from individuals from a region divided by the total number of respondents multiplied by a hundred (Equation (2)). Across regions, percentages were calculated as the sum of the percent of each of the three regions divided by three.
Second, household characteristics were described by zone with a focus on household size, main source of income of the household and the highest level of education attained by a household member. Calculations of household characteristics were conducted similarly as described for the head of the household.
The third sub-section of the results focused on cowpea production inputs, management practices, production and utilization. Adoption rates and reasons for a variety of adoptions, and family or farm locations were first analyzed to determine if differences in adoption can be explained by the climatic context. Then, the labor used by men, women and children in relation to farming operations including threshing, weeding, fertilization, soil preparation, and harvesting and transporting were analyzed. In addition, the types of diseases affecting cowpea production and post-harvest utilization are presented. Furthermore, prices and selling periods within the study regions were characterized as well as the different storage methods used in the different regions.
Finally, an econometrics analysis was performed using the Probit model in STATA to determine the effect of all gathered socio-economic information on new cowpea variety adoption by producers. The Probit model of the form (Equation (3)) was fitted:
where
. The vector
corresponds to the observable characteristics of the individual
i and the vector
represents the coefficients of each of these characteristics in order to qualify the variable, under the assumption that the above model is representative of reality. Theoretically, the binary variable
Yi, is such that
where producer
i adopts at least one new variety of cowpea, and when
, indicates the producer does not adopt a new variety of cowpea.
Empirically, the model used in this work is written as follows in Equation (4):
4. Discussion
From the results of our study, we can define the average head of the household in our three study regions as middle aged (52–54 years old), married (95–100%), and -illiterate (84%) and male (95–100%). These results are consistent with the last Senegalese census where the average age was estimated at 55 years old, the overwhelming majority of whom are married and illiterate in the rural area [
12]. There was only little variation across our study regions that do not fit this description of the head of the household. Auman et al. [
14] compared male versus female household headship and concluded that compared with male household heads, female heads of households were significantly less educated, owned land and cultivated smaller land parcels, were less efficient in agricultural production and disposed of a significant portion of the produce in the local market. The reasons were that most female heads of household in agriculture were divorced, marginalized, and reside in places where there was a male labor migration. The latter occupies an increasingly important place in the income of rural households in the groundnut basin of Senegal [
15]. Other researchers also agree with the conclusion that there is a significant difference in male and female heads of household [
16,
17]. When based on gender and marital status, most heads of household in our study regions being male and married might project a stable environment compared with the alternative discussed in the literature. However, literacy levels reported for most of the heads of the household in our study were low. Despite a married male-dominated head of household in the study region, the low literacy rate could decrease the tendency of adopting efficient agriculture practices to improve crop yields.
The characteristic of the entire household in our study regions could also be summarized as highly agriculture dependent (87%) household, with low literacy (26% least primary school), and big family size with an average of 15 members. Purwantini et al. [
18] concluded that the level of education of the households, the number of people in the household, and cropping intensity affect household agricultural income significantly. When households are highly educated, there is an increased diversification of income sources, a general increase in household income, and an improvement in household livelihood [
19,
20]. Household size determines per capita income of the household and that in turn determines access to financial credit and government subsidies when necessary [
21].
The median cowpea yields significantly varied across the study regions from 35–100 kg ha
−1. These yields are well below the average cowpea yield of 300–400 kg ha
−1 reported for Senegal and sub-Saharan Africa [
22,
23]. Only a few respondent farmers in our study reported cowpea yields above 200 kg ha
−1. This situation is explained mainly by the secondary nature of traditional cowpea varieties in most agricultural production systems in Senegal, since it is essentially used as an associated legume crop to fix nitrogen and thus boost the yields of cereals such as millet and sorghum. This low cowpea yield in West Africa is explained by Baoua et al. [
24] in a study in Niger and listed factors such as poor agronomic management practices (e.g., inadequate weed control, seeding rates, fertilizer application), pressure from crop pests, aphids and caterpillars, diseases and weeds that cause significant yield losses. Participatory farmer field school (FFS) approach could be one channel for communication and dissemination of improved technologies to improve cowpea yields. Similarly, Omomowo and Babalola [
25] described drought, salinity, excessive demand among farmers for synthetic chemicals, the impacts of climate change, declining soil nutrients, microbial infestations, and pest issues as challenges of cowpea production. The authors suggested the deployment of bio inoculants, applying climate-smart agricultural (CSA) practices, agricultural conservation techniques, and multi-omics smart technology in the spheres of genomics, transcriptomics, proteomics, and metabolomics, for improving cowpea yields and productivity. However, these climate smart technologies suggested might be appealing to researchers and educated farmers but considering household education and awareness at the farm level in our study regions, there is more work to be done at a more basic level. Among those basic things are short-term trainings regarding best crop management practices, demonstration of different varieties, creating extension systems for delivery information on available technologies, and marketing opportunities (timing of sales of grain and fodder) for cowpea grain and fodder.
A major reason why reported yields were very low was that majority of farmers in the study regions did not use improved varieties. In addition, the main reasons for not using improved varieties were the limited availability of seeds and little awareness of improved varieties and agronomic management practices. Institutions that study cowpea within the region and extension services should be supported to increase the availability of improved varieties and use by farmers. Studies conducted elsewhere reported seed cost as a major barrier to adopting and using improved crop varieties [
26]. However, our findings showed seed costs are not the major barrier for cowpea use in our study region as only 6% of the respondents indicated seed price as a problem.
The three major use of cowpea in the study region were for marketing, livestock feed, and human consumption. The dual- use of cowpea grain for human and fodder for animal consumption should increase government interest in this crop, which provides quality fodder for livestock during the lean season, which coincides with the beginning of fieldwork and the low availability of fodder from other crops (such as peanut or millet stover). To increase the production of cowpea, the use and demand need to increase and be a driver. This seems to be the case with the multiplication of cowpea fodder programs, which could replace peanut fodder, whose prices are increasing at a very steady pace. As a highly drought-tolerant crop with low water requirement and greater heat tolerance, cowpea has the potential for food security in Africa and around the world. Besides cowpea grain, its pods and leaves are also nutritious and edible [
27]. It is a leguminous crop, that should also be promoted for N fixation as part of a crop rotation or as a cover crop to maintain soil fertility [
28]. However, with most of the crop residues being removed, very little residual N is likely to return to the soil. More research is needed to compare the value of the residue for crop production as compared to being used for livestock feed. Promotion on the various uses of cowpea in and outside the study region, creates a demand for the crop, motivates farmers to increase production, and creates a fertile environment, more markets, and profit.
The effect of socio-economic status of producers extends beyond the choice of cowpea varieties. Once cowpeas are planted, management of the crop and after harvest, choice of proper storage also require knowledge and economic potential. In our study region, 60% of producers have not developed control strategies for diseases and pests. The popular cowpea storage is using cans. Due to the large number and diversity of cowpea diseases and pests, an integrated set of management at different stages of cowpea growth was recommended [
29,
30]. Dissemination of chemical free hermetic bags for cowpea storage has also improved cowpea storage in most parts of Africa, but due to several alternative hermetic bags, testing and making the best storage available to producers may be essential [
31]. To increase productivity and to reduce post-harvest losses in storage, training, awareness, and financial support may be required.
The adoption of improved varieties was explained by three sets of variables including access to information, production system, and the characteristics of the household. These groups of variables are defined by the literature and the context of the study. While some research had focused particularly on household and producer characteristics or market practices to estimate the probability of adopting a new crop variety [
32,
33,
34], to our knowledge, no study considered these three groups to estimate the adoption of new cowpea varieties in the West-African Sahelian region. Access to information regarding the usage of new varieties is an important factor that affects adoption [
35]. The importance of information capability through multidimensional sources to improve producers’ production and marketing decisions have been reported in recent studies [
36,
37]. Our descriptive analyses showed producers could access information on improved varieties through five channels: markets, extension services, urban centers, their peasant neighbors, and producer organizations. In the current study, extension services and producers’ organizations were important factors affecting the use of improved cowpea varieties. Compared to producers using cowpea as an associated crop, farmers dedicated to sole cowpea production are more likely to use improved varieties. In addition, farmers using organic fertilizer are more likely to use the improved cowpea varieties possibly to take advantage of biological N fixation. Market-oriented producers and those who use cowpea fodder for livestock are also likely to adopt improved varieties with greater fodder production.
5. Conclusions
The specific objective of the current study was to analyze the socio-economic characteristics of cowpea production systems, gather baseline information on adoption of improved dual-use cowpea varieties in the Senegalese peanut basin, and study correlation between socio-economic characteristics and variety adoption. Results of the study showed most heads of the household in our three study regions as a middle aged (52–54 years old), married (95–100%), illiterate (84%), and mostly men (95–100%). The characteristic of the entire household in our study region could also be summarized as highly agriculture dependent (87%), with low literacy (26% least primary school), and big family size with an average of 15 members. The median cowpea yields significantly varied across the study region and varied from 35–100 kg ha−1, which was well below the average yield reported for sub-Saharan Africa. The Majority of farmers do not use improved varieties, and the main reasons for not using improved varieties were lack of seed availability and little awareness of improved varieties. The three major uses of cowpea in the study region were for marketing, livestock feed, and human consumption. The effect of socio-economic status of producers extends beyond the choice of cowpea varieties to cowpea production, management, and storage. Access to extension services, membership in producers’ organization, sole cowpea production, organic farming, market, and livestock oriented production systems, access to large acreage of farmland, access to credit, dependence on agriculture as the main source of household income, and literacy of the head of household seem to have a positive effect on the likelihood of using the improved varieties. We concluded the need for training, access to improved seed, awareness, and financial support to producers to increase the adoption of new and improved cowpea varieties to increase yields, profitability, and nutritional security among smallholder farmers. The results presented in this paper are based on baseline survey data in the three regions of Senegal and it is a unique (novel) contribution connecting technology adoption with socio-economics of the region. Results have to be taken with the context of the regional and other limitations and further research on the impact of recommended interventions (training, access to improved varieties, awareness, and financial support) in technology adoption is crucial.