A Review of the Socio-Economic, Institutional, and Biophysical Factors Influencing Smallholder Farmers’ Adoption of Climate Smart Agricultural Practices in Sub-Saharan Africa

Abstract

Climate change and variability are characterized by unpredictable and extreme weather events. They adversely impact the highly susceptible smallholder farmers in sub-Saharan Africa, who heavily rely on rain-fed agriculture. Climate smart agriculture (CSA) practices have been extensively promoted as offering long-term solutions to changing climate conditions, while enhancing the productivity and sustainability of African agricultural systems. Despite this, the adoption rate remains low among smallholder farmers. Understanding the factors that influence adoption of these practices among this key farming community is therefore necessary to increase their adoption. In this paper, we review and summarize findings from existing studies on the factors that influence the adoption of CSA practices by smallholder farmers in sub-Saharan Africa. Our review reveals that land tenure security, access to information and extension services, and affiliation to group membership positively influence adoption. On the other hand, gender, risk perception, and off-farm income had conflicting effects by reporting both positive and negative influences on CSA adoption. We conclude that CSA adoption options are local-specific, and their development and implementation should emphasize locally tailored knowledge, skills, and resources.

1. Introduction

Agriculture is the pillar of Africa’s economic growth and development [1]. It is dominated by smallholder farmers [2], who produce up to 70% of food consumed on the continent [3]. It contributes 16.9% of the total GDP (Figure 1) and employs more than half of the total labor force. More than half of this consists of women in many countries [4]. Thus, agriculture provides a livelihood for thousands of smallholder farmers, who constitute approximately 80% of all farms [1]. Despite this significant role, smallholder farmers in sub-Saharan Africa are the most impoverished community, characterized by high levels of poverty and marginalization [5]. They have limited access to government services, land, capital and markets, public infrastructure, and climatic information, factors that are crucial to agricultural production [6,7,8]. Further, they farm on fragmented farms of poor-quality soils without basic agricultural knowledge and limited extension services [9]. Their reliance on rain-fed agricultural systems with low adaptive capacity [10] increases their vulnerability to changing climatic conditions [11]. This results in a reduction in agricultural yields and an increase in poverty and food insecurity levels [12]. These impacts are exacerbated by deteriorating arable lands caused by increased runoff frequency and soil erosion [13,14], weak technological inputs, and low productivity [15]. Consequently, this situation negatively impacts the four pillars of food security: availability, accessibility, utilization, and stability [12,16].

Future extreme weather events, such as rising temperatures, unreliable rainfall, and consistent droughts, are projected to increase, with destructive consequences in sub-Saharan Africa [18,19]. They compromise agricultural production by altering temperature, and water availability [20], thereby negatively impacting the basic elements of food production, such as soil, water, and biodiversity [21,22]. For example, they can interfere with plant growth processes by affecting crop output, development, and survival, trigger insect pests, weeds, and diseases, or lead to soil degradation [23]. Livestock production will be impacted through water and heat stress, vectors and diseases, or reduced feed quality [24,25]. Africa’s staple crops (maize, wheat, sorghum, and millet) are projected to be impacted the most [26]. The results are less income from farming, increased risks, distorted markets, and increased food prices [5,27].

Evidence of farmer perceptions of these projected changes and the frequency and severity of extreme events have already been recorded in different parts of sub-Saharan Africa, including Ethiopia [28], Niger [29], Ghana [30], Nigeria [12], Burkina Faso and Ivory Coast [31], South Africa [32], Benin [33], Zimbabwe [34], and Kenya [7,35]. The reported changes include meteorological droughts, unreliable and erratic rainfall, fluctuations in the cropping calendar, and an increase in atmospheric temperatures. These changes have negatively impacted agriculture through crop failure, death of livestock, famine, and outbreaks of pests and diseases [11,12,36]. This scenario is anticipated to get worse in the future because of Sub-Saharan African agriculture’s heavy reliance on climatic conditions [37], declining per capita food production [38], projected population increases, and urbanization [39].

Although sub-Saharan African smallholder farmers have proven to be resilient [10], climate change is likely to outpace their current coping capabilities. Newly unfavorable growing conditions and modification of growing seasons will likely worsen the situation. To reduce their vulnerability and enhance household incomes, it is necessary to adopt agricultural practices that ensure higher agricultural productivity. Previously, this was achieved by expanding cultivated land [10,40]. Since this is no longer sustainable, developing and adopting practices that enhance yield per hectare are required. One way of achieving this is to develop smallholder farmers’ capacity to adopt CSA practices, a crucial prerequisite in attaining the United Nations Sustainable Development Goal 1 (end poverty) and Goal 2 (end hunger), achieving food security and improving nutrition while promoting sustainable agriculture [41].

The concept of CSA was proposed by the Food and Agricultural Organization of the United Nations [41] to enhance food productivity, achieve food security and address climate change. Its purpose was to accomplish three goals: improve and sustain agricultural productivity, improve agricultural adaptation and resilience, and reduce greenhouse gas emissions [42]. These approaches involve promoting agricultural practices that increase productivity while promoting the farmer’s resilience to climate change. Despite this potential, smallholder farmers in sub-Saharan Africa face several challenges and lack the capacity to adequately adopt these processes, thus CSA adoption remains low [43,44,45,46]. The CSA practices practiced by sub-Saharan African smallholder farmers are presented in

Table 1. CSA practices practiced by smallholder farmers in sub-Saharan Africa.

Management Type	Practice	Description	Effect	References
Crop management	Agroforestry	Integrating trees/shrubs into crop and/or pasture land	Improve soil health Carbon sequestration Provides fuel wood Provide fodder for animals	[35,47,48,49,50,51,52]
	Afforestation	Planting trees in an area without trees	Control soil erosion Carbon sequestration Provide fuel wood Sales enhance income Acts as windbreaks	[35,47,48,49,50,53,54,55]
	Changing cropping calendar	Shifting planting or harvesting dates (early or later) to optimize yields.	Increases water use efficiency Mitigate drought/flood impacts Improve yields	[56,57,58]
	Cover cropping	Planting crops after the main crop.	Improve soil structure Reduce soil erosion Increase organic matter Enhance water retention	[13,47,49,58,59,60,61,62]
	Crop diversification	Growing a wider variety of crops that include indigenous varieties.	Enhance soil health Enhance pest and disease resistance Increase climate change resilience Enhance farm productivity	[54,63]
	Crop rotation	Cultivating crops in the same piece of land between seasons.	Enhance nutrient use efficiency Reduce pest and disease pressure Enhance water infiltration	[47,49,59,61,64,65,66]
	Intercropping (mixed cropping)	Planting more than one crop species on the same land at the same time.	Minimize crop failure risks Enhance soil health Control pests and diseases Efficient resource utilization	[49,55,58,67,68,69,70]
	Improved crop varieties	This involves the use of: Drought resistant varieties Early maturing varieties Climate resilient varieties	Reduce water stress Improve yields	[47,50,64,71]
Farm management	Contour farming	Aligning farm operations like tillage and planting with natural curves of the field.	Reduce erosion Improve water infiltration Minimize fertilizer loss Increase in crop yields	[69,72]
	Terracing	Creating flat level platforms on sloping land.	Reduce erosion Increase water infiltration	[7,73]
	Precision farming	Using technology and data to make informed farming decisions about planting, fertilizing, watering, etc.	Optimize resource use Minimize waste Reduce input costs Increase yields	[74]
	Mulching	Covering the soil surface with a layer of organic material.	Enhances soil moisture retention Suppresses weeds Regulate soil temperature Enhances soil organic matter Improve soil structure	[58,75]
	Nutrient Management	Application of nutrients based on plant requirements.	Reduces environmental impacts Reduces greenhouse gas emissions Increases nutrient use efficiency Improve crop yields	[69]
	No tillage/minimum tillage	Planting crops without tilling the soil or little disturbance.	Reduces soil erosion Improve soil structure Reduce labor costs Increases soil organic matter Enhances water infiltration Increases nutrient retention Improves carbon sequestration	[76,77]
	Organic fertilization	Use of materials derived from plant, animal, or mineral sources, such as compost, manure, etc., to enrich the soil.	Improve soil health and structure Enhance water retention Increase nutrient availability Ensure plant health Reduce reliance of synthetic fertilizer	[21,78,79,80,81]
	Insurance	Farmers purchase insurance policies to cover their potential crop yield.	Protect farmer from losses Help cover costs Ensures financial stability	[52,54,82,83]
	Biological pests, weeds and Disease management	Reducing the reliance on chemicals to control pests and diseases.	Cost effective Environmentally friendly Reduce human health risks Self-sustaining Conserves biodiversity	[75]
	Integrated pest management	Combining multiple strategies to minimize pest damage.	Minimize Environmental Impacts Reduce human health risks Protects beneficial organisms Promote health ecosystem	[58,84]
Livestock management	Livestock diversity	Rearing a variety of animal species and breeds.	Provide more options to adaptation to changing environments Enhances ecosystem health Diversify income streams Support diverse grazing patterns	[52,54,85,86]
	Crop-livestock integration	Crops and livestock are managed together.	Improve soil health Reduce reliance of external inputs Increase farm diversification Enhance farm resilience	[70,76]
	Rotational grazing	Moving animals periodically between pastures within a grazing area.	Allow resting pastures to recover Promote soil health Enhances pasture growth Promote animal health	[54]
	Better breeding practices	Improving the overall health and genetic diversity of animals by selecting breeding stock and managing inbreeding.	Improve animal health Enhances yield More resilient animals Enhance food security	[52,57,87]
	Diversifying pasture	Increasing the variety of pasture plant, species such as grasses, legumes, and forbs.	Create a resilient grazing system More productive forage Enhance animal health	[85]
	Stocking rates	Balancing the amount of livestock grazing on a specific area with forage supply.	Prevents pasture damage Controls soil erosion Enhances forage production Increases animal performance Optimizes economic efficiency	[87,88,89,90]
	Manure management	How manure is captured, stored, treated, and used	Enhances nutrient cycling Improves soil health Minimize risk of water and air pollution Improve farm economic efficiency	[51,77,78]
Post harvest management	Building resilience along the supply chain	Strengthening the entire supply chain	Withstand climate-related shocks Improve resilience	[91]
	Storing, handling and transporting produce	Improved storage, handling and transportation. Use of bags that minimize oxygen entry.	Reduce losses during handling Reduce losses during transport Reduce storage losses to pests	[91]
Water management	Water harvesting	Collecting and storing rainwater or sinking boreholes for farm use	Irrigate crops Conserve moisture Increase yields	[26,37,57,92,93]
	Irrigation scheduling	Determining the optimal timing and amount of water to apply.	Enhance water use efficiency Minimizes environmental impact Improves yields	[88,90,94]
	Improving drainage	Rate and extent of water movement into and out of the soil.	Improves soil aeration Supports beneficial soil organisms Controls soil erosion and runoff Improve soil health	[57,58]
	Planting pits e.g., Zai pits	Small depressions in the field for planting seeds and concentrating fertilizer, manure, and water.	Improve soil fertility Increase water infiltration and retention Enhance crop growth	[95]
	Weather forecasting	Provide accurate predictions of future weather conditions.	Enable good decision making Optimize practice schedules Minimize weather related loses	[22,58]

.

Agricultural adaptation to climate change is complex, and farmer choices are dependent on socio-economic, institutional, and biophysical factors. Adoption of CSA practices occurs at the farm-scale level and is led by farmers who are the managers and sole decision-makers [96]. The adoption of these practices has been documented to deliver positive results, such as increased food productivity, provision of diet diversity, enhanced household incomes, and reduction of greenhouse gas emissions [43,97,98]. For example, Arslan et al. [99] reported that legume intercropping significantly increased legume yields in Zambia, while Issahaku et al. [100] documented a reduced-climate change induced yield loss through crop calendar management and irrigation in Ghana. In another study, Zizinga et al. [101] stated that mulching not only compensated for limited precipitation but also increased maize yields in Uganda.

Although past studies suggest that farmer adoption of new practice is based on profitability [102], many other factors drive adoption decisions depending on practice availability, accessibility, and affordability [103]. Thus, farmers by nature employ a mix of adaptation strategies that can be complex and influenced by multiple factors, some simultaneously [98]. They can either adopt a single or multiple practices or not adopt at all based on several factors and ability [104]. Therefore, understanding how these components influence farmers’ decisions in selecting a specific CSA practice is necessary to aid the formulation of effective interventions and policies that promote their successful adoption. This paper, therefore, reviews the socio-economic, institutional, and biophysical factors that influence smallholder farmers’ adoption of CSA practices in sub-Saharan Africa. This determination is crucial to allow the development of well-informed and feasible strategies that facilitate successful CSA adoption by smallholder farmers.

2. Factors That Influence the Adoption of CSA Practices in Sub-Saharan Africa

Adoption of CSA practices offers potential benefits to farmers and the environment. Understanding the factors that influence farmers’ adoption decisions is crucial to scaling the adoption of CSA practices. It is through this background that this paper synthesizes and summarizes the factors that influence adoption of these practices by sub-Saharan African smallholder farmers. These factors are divided into three major groups: (i) socio-economic, (ii) institutional, and (iii) bio-physical factors (Figure 2).

2.1. Socio-Economic Factors

2.1.1. Farmers’ Education Level

Higher levels of education are associated with access to information on improved agricultural practices and their adoption [51,105]. This resolves the reported lack of awareness of climate change impacts and its effective adaptation strategies [106,107]. Further, education enhances the farmers’ awareness of climate risks, thereby positively shaping their climate change perceptions, beliefs, and attitudes [96,108]. It enhances the farmer’s ability to receive, decode, and understand climate change information and positive outcomes associated with adopting agricultural measures that minimize climate impacts [109,110]. Consequently, it positively influences the farmer’s behavioral intentions towards adopting CSA practices [111,112]. This was documented in Nigeria, where education increased Nigeria farmers’ CSA practice adoption [82]. Thus, educated farmers are more likely to adopt CSA practices compared to their uneducated counterparts.

2.1.2. Gender

The gender of the household head has a great influence on CSA adoption. In many African cultures, agricultural production is controlled by different household members, with women playing key roles in farm productivity, such as weeding, hoeing, and plantation. However, women have unequal opportunities that constrain their rights to own and control resources. For example, traditional and cultural customs limit their ability to own land [35,113] and natural assets, have access to education, and deal with health issues and credit and market facilities [114,115]. Furthermore, communal resources have been biased, by excluding and discriminating against women when shared or privatized [116]. For example, in Malawi, female farmers have limited access to productivity-enhancing inputs and resources, such as capital, animal power, and credit [114,117].

Women are also constrained by time by their household chores, including long distances to fetch water, marketing, household chores, etc. [35]. These factors directly influence agricultural productivity and the adoption of CSA practices. The time spent on these activities could be spent accessing information on CSA practices and therefore negatively impacts their adoption capacity. Thus, even in situations where there is the same climate change exposure for male and female farmers in a specific location, there are different levels of vulnerability and adaptive capacity for men and women [118]. These under-resourced and undercapitalized gender gaps reduce efficient investment in agriculture among women and therefore limit their capacity to adopt CSA practices in the plots they manage. In spite of this, female-headed households have been perceived to be more receptive to adoption [35,118]. This can be attributed to sustained women’s empowerment to play increasing roles in household decision-making [35].

2.1.3. Farmer’s Age and Experience

Farmers’ age is a proxy for farming experience, and these two are key determinant factors that drive farmer decision-making processes, such as adoption of CSA practices [51,119]. Studies conducted in Ethiopia [15] and the South African regions [111] have demonstrated that age and experience provide positive perceptions towards adopting CSA practices. This is especially so with older farmers, who are more likely to have a better understanding of climate patterns through experiences of past and present climatic conditions over time [109]. This was observed in Kenya, where older farmers were more likely to apply animal manure [51]. As opposed to inexperienced youth characterized by economic hardships and lack of assets with low CSA adoption rates [111], experienced farmers are risk averse and more willing to take actions that reduce climate change’s impacts on their farming operations [110]. This demonstrates that age and experience strongly influence smallholder farmers’ willingness to adopt CSA practices.

2.1.4. Membership/Affiliation with Social Groups

In sub-Saharan Africa, social groups play significant roles in influencing CSA adoption [110]. They provide information on informal credit sources and spread information about climate change and adaptation technologies [114] through informal platforms, especially among female farmers [35]. This suggests that the smallholder famers’ gender can influence their social norms and, in turn, their intention to adopt CSA practices. An identity that stresses attachment, empathy and care has been observed among female farmers [120], making them more likely to adopt CSA practices based on affiliation to a group. Once a social bond is built within the group, participants learn from each other, set standards amongst themselves, and constantly monitor each other [121]. Their awareness of how their behavior is viewed by other farmers builds their confidence and trust to act in ways their colleagues approve. This enhances their normative beliefs and intentions to adopt CSA practices.

2.1.5. Farmer’s Perception and Attitudes

The perception farmers have on climate change as a threat and the severity of its impacts on their farming activities is a voluntary motivator for CSA adoption [122], if they have the right information. Studies in South Africa [56], Kenya [112], and Ethiopia [97] found that farmers with positive perceptions and attitudes to climate change are more likely to adopt CSA practices. They are influenced by their subjective assessment and perception of the factors that cause climate change [123]. On the other hand, a study in Tanzania found a higher tolerance to risk hindered adoption of CSA practices [124]. Thus, risk averse farmers hesitate to adopt newer practices. Some farmers are also not willing to adopt these practices, because they do not believe that climate change is real [125], and yet others interpret it as “scientific uncertainty” [126]. Thus, a farmer who perceives climate change as a threat is more likely to evaluate its severity, seriousness, and vulnerability and the benefits of pursuing preventive measures [127]. Hence, the perceived occurrence and severity of the risk motivate them to adopt a recommended CSA practice to mitigate the perceived consequences. Success is dependent on how they perceive and respond to the type of risk involved [128]. The farmer’s investment decisions and response options will depend on their perception of the threat. A successful strategy requires that famers first perceive the changes that have occurred and then identify the necessary adaptations to be implemented. Thus, this involves four stages: (i) perceived climate change, (ii) perceived climate change impacts, (iii) farmer awareness, and (iv) farmer acts (Figure 3).

2.1.6. Family Size and Cost of Labor

In sub-Saharan Africa, family size is an indicator of labor availability [51]. Women and children provide most of this labor [129]. It is therefore expected that larger households have a higher likelihood of adopting different CSA practices on their farms compared to their smaller counterparts [112,130]. Larger families also contribute to enhanced incomes through increased farm productivity or engaging in other non-farm economic activities. These incomes are then ploughed into the farming operations, where they can be used to implement CSA practices. However, this is not always the case, as conflicting results of negative relationships between family size and agricultural practice adoption have been reported [131,132]. This may be because of smaller households opting to use hired labor. This observation is evident especially in wealthy and married male-headed households that engage in full-time farming [111].

2.1.7. Access to Credit/Finance and Affordability

Smallholder farmers in sub-Saharan Africa are constrained by credit market imperfections and stringent conditions for credit accessibility [133]. Credit support significantly increases farmers’ adaptive capacities and resilience against climate change risks [134]. Availing credit enhances their farm productivity and household incomes, a key ingredient of expanding and strengthening risk mitigation strategies, particularly in adoption of agricultural practices that mitigate climate change risks [135]. Adoption is dependent on availability of credit, either from their own savings or borrowed. Access to credit has been positively associated with CSA adoption [136]. For example, ref. [7], associated access to credit with the adoption of mixed cropping and use of plant calendars in Kenya. On the other hand, credit unavailability hampers adoption [108,122]. This calls for enhanced credit availability to facilitate CSA adoption [63]. It should, however, be noted that credit access and choice of CSA strategies have produced mixed results [137], an indication that more studies are necessary to establish the role of credit access in CSA adoption.

2.1.8. On-Farm and Off-Farm Income

Households with higher income and assets are more likely to adopt CSA practices because they may have greater access to information and financial resources and are less risk averse [136,138]. On the contrary, poor households, which are the most vulnerable, are unlikely to adopt CSA practices [139]. Extra income generating activities other than farming can also influence CSA adoption and use [111,122]. Here, CSA adoption may not be taken seriously by households with a separate principal income source apart from farming. They will not be motivated to counter climate change impacts but instead will lean to the other income source for livelihood support. However, it should be noted that the extra income can be ploughed back to farming to implement CSA practices. This demonstrates that the effect of income on CSA adoption is not evenly spread among households with different socio-economic backgrounds.

2.2. Bio-Physical Factors

2.2.1. Farm Size and Location

Farmer perceptions on climate change and adaptation options are local-specific. They are more influenced by reginal elements like local infrastructure, farm size, resources, policies, access to information and cultural ideologies, among other factors [140,141]. For example, closeness to urban centers [140] and proximity to agricultural markets [142] have a positive effect on CSA adoption, while distance from farmstead to farm site has a negative impact [143].

2.2.2. Access to Natural Resources

These are the resources and ecosystem services provided by the natural world [144] that determine the suitability of agriculture, economic, and technological capacity for adoption of a relevant CSA practice [145]. There is much pressure on resources like water, food, land and energy in sub-Saharan Africa, as they have been worsened by demographic and climatic changes. The location of farmers in relation to accessibility of these resources can present an opportunity, not only to implement CSA practices but their ability to adopt them [65,146]. For example, farmers who are closer to a water source are more likely to adopt CSA practices, like irrigated crop diversification, and vice versa [147].

2.2.3. Climate Condition and Access to Climate Information

Farmers’ perceptions and behavioral responses to climate change impacts on agriculture are influenced by recent climate events, together with their own personal experiences of, e.g., extreme events, rainfall frequency, timing and intensity [47]. This emphasizes the importance of knowledge of local climate, weather forecasting and early warning systems in farmer decision making regarding CSA adoption options [64,114]. Information derived from personal experience is more likely to provide greater weight than that derived from external sources [47]. For example, farmers experiencing an environmental problem like a drought form an environmental perception based on this recognition [148]. Farmers with experience of environmental hazards are more cognitive and perceptive to climate change, and more likely to act to reduce climate impacts [64]. This demonstrates that local climate conditions have a positive influence on the farmers’ decision towards adoption of CSA practices. Thus, the need for enhanced accuracy, accessibility, and reliability of climate information to smallholder farmers is more critical for enhanced adoption of CSA practices.

2.2.4. The Cost of Practice and Its Benefit

CSA practices are aimed at efficient utilization of limited resources to address challenges regarding agricultural productivity. To effectively achieve this goal, it is necessary for farmers to assess the benefits, risks and costs of a practice before their adoption [149]. Since farmers prefer profitable practices [10,150], they tend to avoid practices with higher implementation costs. They also plan accordingly to minimize losses from climate risks, such as droughts, uncertain rainfall pattern, and floods, when they are aware of them [149]. Thus, the installation and operational costs and potential benefits of a particular practice are critical factors for farmers, whose goal is to maximize profit while minimizing setbacks during and after adoption [151]. Farmers’ capacity to respond to a particular practice is influenced by how they perceive the threat, and their evaluation of the effectiveness of the practice (Figure 3). The final decision will be determined by the availability of resources necessary to implement the practice. A practice that is perceived to be costly to implement will discourage adoption and vice versa [35].

2.3. Institutional Factors

2.3.1. Government Interventions

Many sub-Saharan national governments are actively working on possible solutions, like initiation of governance systems and policies, to mitigate the adverse effects of climate change, which can integrate adaptation to climate change to sustainable development, food security, and poverty [46,58,152]. These programs are normally funded by international funders targeting the most vulnerable populations. An example is the United Nations Development Program’s Africa Adaptation Program [153], whose mandate is to enhance adaptive capacity. This promotes early adaptation action with the aim of increasing resilience to climate change among poor smallholder farming households. Other examples include Strengthening Adaptation and Resilience to Climate Change in Kenya Plus [154] and the climate-resilient green economy strategy in Ethiopia [155]. The effectiveness of these programs is rather low [156], because they are either developed at national level, based on few case studies, or solely focused on technology [156]. Further, they fail to account for the high heterogeneity of farming systems in their planning [157,158]. This is slowly shifting to conform with the farm system-oriented approach [159]. Adequate knowledge of vulnerability levels, available CSA practices for adoption and farmers’ capacity to adopt are necessary for successful policy formulation and implementation.

Sub-Saharan African governments have been mandated by the Conference of Parties (COP) to formulate and implement National Action Plans (NAPs). They should identify medium and long term adaptation needs and strategies to address them. The goal is to reduce climate change vulnerability by building adaptive capacity and resilience [160]. Further, the African Union Climate Change and Resilient Development Strategy and Action Plan supports regional collaboration on climate change. This provides a framework for joint action.

Governments can encourage adoption of CSA practices by subsidizing desired practices to encourage adoption. An example is the enhanced adoption of a drought tolerant seed in Malawi through the Farm Input Subsidy Program [161]. Another example is introducing insurance policies to compensate farmers for losses incurred for spending more towards adopting a practice [162]. Land ownership has been positively associated with prudent land management [163], specifically with female farmers [35]. Therefore, improving land rights can encourage farmer engagement towards investing in CSA practices. The provision of credit, especially for those requiring it, will facilitate adoption. Examples include water management systems in Kenya [164] and groundwater motor pumps in Nigeria [165].

2.3.2. Access to Information and Extension Services

Access to technical information through extension services or media is key regarding awareness of advanced technology and its utilization [148,166], because it decodes information into a format understandable by farmers. Increasing the smallholder farmers’ knowledge of climate change impacts on agriculture, and of the benefits of adaptation, will directly influence their decision-making process in adopting or not, and in which practice to adopt (Figure 3). Access to information strengthens farmers’ adaptive capacity and positively influences their attitudes towards adopting CSA practices. Studies in Ghana [167], Kenya [149], Zimbabwe [89], South Africa [111], and Nigeria [147] have demonstrated that farmers with access to extension services have higher acceptance of CSA adoption rates than their counterparts who do not. On the contrary, a lack of information hampers adoption [35]. This acceptance is attributed to the training and easy access to information through extension services that empowers them to make informed agronomic decisions. Thus, information access through extension services influences smallholder farmers’ intentions to adopt CSA practices. Those informed are more likely to adopt than those who are not.

2.3.3. Land Tenure

Secure land tenure strengthens smallholder farmers’ resolutions to invest in long term agricultural activities in sub-Saharan Africa [35,112,168,169]. On the contrary, land insecurity limitations and interventions have resulted in negative consequences, especially where elites are favored at the expense of disempowered groups of people [170]. This creates a situation where farmers desire a strong tenure security system rather than the existing informal and customary tenure without written title deeds [49,171], and practices which do not allocate land to women and youth [169,172]. The pressure of reduced farming land as fathers subdivide their land to their sons or gift small portions to women [173] compounds the problem. These informal tenure systems not only hinder CSA adoption but also constrain women and youth from making adoption decisions. Further, smallholder farmers are unprepared to cope with rapid changes towards privatization of land and emerging macroeconomic trends associated with population growth, such as increased food demand, rapid urbanization, and financial flows [174]. This means that secure land tenure with accompanied incentive for land development is critical for adoption of CSA practices. This was demonstrated by the study of Kpadonou et al. [175], where land ownership encouraged farmers to adopt CSA practices in West Africa.

2.3.4. Agricultural Policies

Although CSA adoption is flexible, with context-specific solutions, successful implementation requires coordination between the farming community and policy makers to identify feasible practices and overcome competing interests and demands [47,176]. Unfortunately, formulated policies lack basic infrastructure and support from all stakeholders, while some are designed to produce off-farm benefits [44]. They do not entice farmers, the adopters, and therefore are often not successful. To take advantage of the site specific nature of CSA practices, location and situational specific policies should be formulated. These will allow the development of effective practices that complement one another and provide farmers with an opportunity to adopt multiple practical strategies in different combinations [177].

3. Interrelationship Between the Influencing Factors

We grouped the factors that influence adoption of CSA practices as found in the literature into three main categories. “Socio-economic factors” represent personal and financial aspects, “Institutional factors” represent institutions and government structures, while “Bio-physical factors” represent environmental factors. “Socio-economic factors” characterize the interrelationships between farmers and the bio-physical and institutional factors. In

Table 2. Interrelationships between the factors influencing adoption of CSA practices among sub-Sharan African smallholder farmers.

Factor	Variables	Explanation
Bio-physical	Farm size and location, climate conditions.	These factors determine how quickly, and severely negative impacts become visible. For example, the severity, frequency and forecast information for droughts/floods can determine which practice is appropriate and necessary.
	Type of practice	The CSA practice must be available, accessible, and appropriate to the existing farm practices. Economic barriers to adoption can arise if the practice is expensive and requires access to natural capital and finance to implement. The financial returns (profitability) from cost incurred or reduced following adoption can also influence whether the practice is adopted.
Institutional	Policies, government interventions, Land tenure and property rights, extension and training.	Policies and government interventions may be used as ‘carrot and stick’ tools to encourage change in behavior. Farmers must have access to relevant information, and extension services are crucial in information dissemination. Land tenure and security influence the farmers’ ability and willingness to adopt a practice that can be dependent on its location, size and how long they have access to that land.
Socio-economic	Credit availability, on and off-farm income	Access to credit to cover implementation costs and potential profits to be accrued following practice adoption influences this adoption. However, this can depend on personal and institutional factors. Further, agricultural policies, availability of extension services and government interventions may play significant roles in farm income and access to credit and, by extension, adoption of a practice.
	Farmer education level, age and experience, attitudes and perception and membership to an affiliation group.	Individual farmers’ attitudes and values can be greatly influenced by peers, age and farming experience. This will most likely affect their individual decision making process on whether to adopt a practice or not. Trust in institutional policies and activities can be critical in adopting a practice. Land tenure security and family involvement can guarantee farming continuity and may have a positive influence on adoption.
	Farmer education, age experience and attitude towards method, risk perception, interests, and trust.	Information about risk and practice must reach the farmer for them to recognize a problem and make them aware of potential solutions (practice). Relevant knowledge includes climate change information, its negative impacts, and potential adaptation practices. Farmer attitude, perception and assessment of risk and practice differ from one farmer to another. This can change over time depending on social background and experience, such as age, association with a social group and education level. Further, if a farmer perceives a practice to be justified, useful and effective, they will likely adopt it.
	Family size and labor	Labor availability is required for adoption of any practice. This can be provided by family labor and, therefore, a practice that allows adoption without major costs is more likely to be adopted.

below, we have provided a brief explanation of the interrelationships between the factors.

4. Conclusions and Future Perspectives

This study aimed at reviewing the findings of existing studies on the factors that influence the adoption of CSA practices, with a particular focus on the sub-Saharan Africa region. Climate change presents an existential threat to food security and livelihoods in sub-Saharan Africa. Therefore, adoption of CSA practices is critical for enhanced food production and climate change mitigation. From this review, smallholder farmers’ adoption decisions are intrinsically linked with three main groups of influencing factors: socio-economic, institutional and biophysical. These factors vary from place to place. What is smart in one location and community may not be successful in another. The review established that adoption decisions are not only influenced by farm management factors but also institutional and social factors beyond the farm gate. Knowledge plays a significant role in informing adoption decisions based on a mix of socio-economic, institutional and biophysical factors. Since actual adoption is driven by farm level characteristics, initiatives that empower smallholder farmers should emphasize locally tailored knowledge, skills and resources. This should be augmented by policies formulated through open and transparent stakeholder engagements accompanied by capacity building and access to resources. On this basis, this study recommends the following:

(i)

Increase research and extension services to develop and promote locally appropriate CSA practices.

(ii)

To facilitate the sharing of information and experiences, smallholder farmers should be encouraged to form or join groups.

(iii)

Sub-Saharan African governments should formulate policies focused on addressing the constraints of adoption. These policies should be coherent across local, national and regional boundaries and sectors.

(iv)

Meteorological agencies should be adequately resourced and trained to disseminate accurate and timely weather information.