Introduction

The adoption of organic matter management (OMM) practices can increase soil nutrient recycling (Ekyaligonza et al. 2022a; Uzoh et al. 2019; Wolz and DeLucia 2018), which in turn minimizes the negative nutrient balances and low soil fertility that are characteristics of most smallholder farms (Adugna et al. 2015; Sanchez 2002; Semalulu et al. 2015; Tittonell and Giller 2013). Some of these OMM practices include agroforestry, mulching, crop residue incorporation, and manure application. Agroforestry can be defined as the deliberate integration of trees or shrubs into a crop and/or animal farm to benefit from the resulting ecological and economic interactions (Plieninger and Huntsinger 2018). In addition, agroforestry systems such as alley cropping, trees planted as hedgerows, and the multitier system are known for improving soil organic matter (Beuschel et al. 2019; Jakhar et al. 2017; Muoni et al. 2019; Sawadogo 2011; Wartenberg et al. 2020). Mulching is another OMM practice that involves covering the fields with fresh or dry biomass such as grass, weeds, or branches with leaves to conserve soil and water by minimizing erosion and improving soil ecology (Erenstein 2002). When mulch material decomposes, it forms organic matter, which improves soil moisture (Cu and Thu 2014), suppresses weeds, minimizes the spread of pests and diseases, and controls soil erosion (Iqbal et al. 2020; Kader et al. 2019; Petrikovszki et al. 2020). Crop residues (CR) can be referred to as the leaves and stalks that are left behind after crop harvest, which when incorporated into the field can accumulate soil organic matter and increase nutrient recycling as they decompose (Aulakh and Garg 2007; Ekyaligonza et al. 2022a; Kaewpradit et al. 2009; Kibunja et al. 2010; Turmel et al. 2015). Manure can be defined as the decomposed plant and/or animal material, which when incorporated into the soil improves soil organic matter, nutrients, and other physical soil characteristics (Belay and Bewket 2013). For instance, a research in the Rwenzori region of Uganda demonstrates that the application of a combination of OMM practices such as alley cropping, farmyard manure application, forage legume integration in a rotation system can improve soil organic matter by 19%, nitrogen by 60–75%, and potassium by 20- 25% (Ekyaligonza et al. 2022b). In the same study, the OMM practices increased maize grain yield by 17% more than the application of 50 kg/ha diammonium phosphate fertilizer. The OMM practices also have an ability to improve Coffee arabica by 54% in comparison to the farming system without any soil amendment strategy (Tibasiima et al. 2023).

Not only does the application of OMM practices improve soil fertility and crop yield but also minimizes the dependence on inorganic fertilizers whose application on soils with low humus content has a low impact on yield (Fageria 2012; Tittonell and Giller 2013). Moreover, the application of inorganic fertilizers is limited due to their prohibitive prices and untrusted quality as some of them are adulterated during the marketing chain (Bayite-Kasule 2009; Mbowa et al. 2015). Therefore, improving soil organic matter through comprehensive organic matter management (OMM) is, besides many other positive ecosystem services functions a precondition for the efficient use of mineral fertilizer and a reduction of erosion and water pollution. If successfully implemented, OMM practices can also contribute to the United Nations Sustainable Development Goals (SDGs) of “Zero hunger” (No. 2), “No poverty” (No. 1), and “Good health and well-being” (No. 3).

Despite the plenty of research about OMM, soil fertility has remained low and farmers have continued to realize only low yields, especially those concentrating on the production of annual crops (Karamage et al. 2017; Muhamud and Joyfred 2015; Roller et al. 2012) due to limited adoption of recommended OMM practices. For instance, Ekyaligonza et al. (2022b) demonstrates that the application of OMM practices can improve maize grain yield by 1.8–5.5 tons/ha higher than the 1.5 tons/ha average yield reported on some Ugandan farms with neither organic matter management nor inorganic fertilizer application. The situation could be worse in mountain areas where other factors such as soil erosion are contributing to the reduction in organic matter hence reducing the soil nutrient balances further. Previous studies have concentrated on soil erosion assessment, adoption of soil conservation technologies, and experimentation of how OMM can improve soil fertility, crop yield and the economy of the farm (Ekyaligonza et al. 2022a, b; Karamage et al. 2017; Muhamud and Joyfred 2015; Tibasiima et al. 2022, 2023) but not on the factors that influence adoption of OMM. Context-specific studies on the factors that influence the adoption of OMM on smallholder farms could be crucial for sustainable organic matter management. Therefore, the question remains; which factors influence the adoption of OMM practices by smallholder farmers?

Based on a combination of three theories: the Theory of Planned Behavior (TPB), the Technology Acceptance Model (TAM), and the Rural Technology Acceptance Model (RuTAM), five adoption theory components were identified (Ajzen 1991; Tambotoh et al. 2015). These included 1) the nature of technology, 2) farmer characteristics, 3) input-related adoption factors, 4) information transfer-related, and 5) institutional-related adoption factors. These adoption theory components are inclusive of the factors that influence the adoption of OMM, which are demonstrated in several studies (e.g. Jha et al. 2021; Kehinde and Shittu 2019; Ndambi et al. 2019; Usman et al. 2020). We thus analyzed the adoption factors in the theories against a specific case of smallholder farms with soil fertility challenges. The aim was to develop a model that can be applied to improve interventions by agricultural extension institutions.

Theoretical perspective on the adoption of organic matter management practices

To map the complexity of farmers’ adoption processes, we developed a hybrid theory from the three adoption theories: 1) the Theory of Planned Behavior (TPB) (Ajzen 1991; Borges et al. 2015), 2) the Technology Acceptance Model (TAM) (Michels et al. 2021; Tambotoh et al. 2015), and 3) Rural Technology Acceptance Model (RuTAM) (Tambotoh et al. 2015). The theory components ranged from behavioral science to the nature of the technology. The TPB considers the attitude and subjective norms of an individual as important factors influencing the adoption processes (Ajzen 1991; Borges et al. 2015). In the same theory, attitude is related to people’s emotions and feelings towards deciding while subjective norms are related to the perceived social pressure such as culture and social dimensions (e.g., gender, awareness, and belonging to an organized group) of a person. Besides this, a person can adopt a given practice if it is perceived as useful and easy to use as described under the TAM (Michels et al. 2021; Tambotoh et al. 2015). In addition, a practice can further be adopted if the prevailing conditions support it as described in the RuTAM model. The conditions that support adoption under the RuTAM model include the availability of inputs, information transfer-related factors, the nature of technology, and the characteristics of an individual such as gender and ability to process information about the technology (Tambotoh et al. 2015).

From the TPB, TAM, and RuTAM theories, we constructed a hybridized theoretical framework (Fig. 1) that guided this study. This hybridized theoretical framework states: The adoption process of a practice can be facilitated if an individual’s characteristics and the institutional-related factors can support it; information about the practice and the required inputs are available, and an individual can apply the required technology with ease. This hybridized theoretical framework is broader than the three adoption theories of TPB, TAM and RuTAM as it is developed from a combination of the adoption components of the three theories. The hybridized theoretical framework could thus be more suitable for mapping the adoption processes of smallholder farmers than the application of single theories. From this hybridized theoretical framework, five adoption components become vivid i.e., farmer characteristics (knowledge, age, gender, culture, and education status), information-related adoption factors, input-related adoption factors, institutional-related adoption factors, and the nature of the technology (use and easiness to apply a technology or practice). We aim to identify if these elements form the core basis for the adoption of existing organic matter management practices and their relevance in the adoption of the new OMM practices.

Fig. 1
figure 1

A hybridized theoretical framework

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Methods

Study area

This study was conducted in the districts of Kabarole, Kasese, and Kamwenge of the Rwenzori Region in Western Uganda (Fig. 2). The region has a tropical climate with an annual temperature of 20–25◦ C and an elevation of 1160- 1800 m above sea level (FAO 2005). The area receives 400 mm of rainfall annually in two rainy seasons i.e. the short rainy season that runs from March to May and the long rainy season that runs from August to November (FAO 2005). The three study districts have an estimated total population of 1,264,644 people: Kabarole district with 298,989 people, Kasese with 694,987 people and Kamwenge with 270,668 people (UBOS 2014). Majority of these people are smallholder farmers with an average farm size of 2 hectares (Njeru et al. 2016). The Rwenzori region was selected as a case study where smallholder-farming systems dominate with a lot of soil fertility improvement adoption constraints (Tibasiima et al. 2022). The communities in the region derive their livelihood from crop and livestock farming. Both perennial and annual crops are grown in the area. The dominant perennial crops include coffee (Coffea spp.), vanilla (Vanilla planifolia), cocoa (Theobroma cacao), tea (Camellia sinensis), and bananas (Musa spp.), while the annual crops are maize (Zea mays), beans (Phaseolus vulgaris) and ground nuts (Arachis hypogaea) (Isgren and Ness 2017; Montserrat et al. 2013). For livestock farming, the farmers keep various types of animals and the most common ones are cattle, goats, and poultry (Montserrat et al. 2013). These indicate the potential for integration of OMM practices for soil fertility improvement in this region.

Fig.2
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Location of the Kabarole, Kasese, and Kamwenge Districts in Rwenzori region, Uganda

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Data collection

To understand the complexity of the farmers’ adoption process, a multimethod approach was applied. From August 2018 to January 2019, preliminary observation on 100 annual crop farms was conducted to find out if OMM is among the farming practices on smallholder farms. The first 18 observed farms were located in three villages within the three study districts of Kasese, Kabarole, and Kamwenge. These villages were recommended to the research team by the Mountains of the Moon University (MMU) and Sustainable Agriculture Trainers Network (SATNET) staff who had previously worked with the farmers. Sustainable Agriculture Trainers Network is a local organization which trains farmers on sustainable agriculture. From each of the selected farms, 15 more neighboring farms were observed. The observation was guided by a checklist focusing on the presence of legume forage crops, composting sites, and alley crops. This was followed by 10 interviews with smallholder farmers who later hosted OMM trials on their fields for over two seasons to improve their understanding of the OMM practices. The selected interview participants were gender balanced. Interviews followed an interview guide with three themes: 1) the characteristics of individual farmers, 2) the factors which influence the adoption of OMM practices with specific consideration of the input related, information transfer related and institutional related adoption factors, and 3) the nature of technology. Two focus group discussions (FGD1 and FGD2) with 10 farmers each (Table 1) were then conducted to validate the data obtained from the farmer interviews. The first FGD (FGD1) involved farmers from Kamwenge and Kabarole since they have a common local language (Rutoro), while the second FGD (FGD2) was conducted in Kasese since the farmers communicate in a different local language (Lukonzo). The FGD participants were selected from the groups that had not received training on OMM but with care to ensure participation of both males and females. The groups were recommended for study by SATNET. A FGD guide was applied in the collection of data from the focus group discussions. The farmer interviews and FGD were conducted in January 2019 (Table 1). To understand the factors and validate the farmer characteristics that influenced the adoption of OMM practices, 18 expert interviews were conducted. The 18 interviewed experts included: three researchers from MMU, one from the National Agricultural Research Organization (NARO), six from the local government (Sub-county and district production department), and eight from NGOs of Joint Efforts to Save the Environment (JESE) and SATNET. The eighteenth expert interview was the data saturation point, as recommended for qualitative studies (Guest et al. 2006). The selection of participants did not follow any particular criteria but they were snowballed based on their knowledge and experience of the OMM practices. Expert interview data was collected between January 2019 and April 2020 (Table 1). With consent from the participants, the interviews both with farmers and experts, as well as the FGDs were audio recorded for easy analysis of the data.

Table 1 Summary of data collection methods and criteria for selecting participants and farms
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Data analysis

The audio-recorded interviews and FGDs were transcribed manually into text and then content analysis was applied following Velten et al. (2015). This was done by grouping the transcribed text into five predetermined themes or categories within a Word document file. The themes included nature of technology, farmer characteristics, input-related adoption factors, institutional-related adoption factors and information transfer-related adoption factors. Further analysis of expert and farmer interviews and FGDs was at three levels. The first level involved a summary of the key terminologies within the context of the theoretical framework. The second level involved the interpretation of the ideas of the expert interviewees (Ei1-Ei18), farmer interviewees (Fi1-Fi10), and FGDs (FGD1 and FDG2). The third level of analysis involved comparing the interpreted findings with existing literature and the hybridized theoretical framework.

Results and discussions

Nature of technology

The adoption of OMM practices can be driven by farmers’ perceptions on the usefulness of the technology. An example is cited in FGD2, 2019: “We decide based on the previous soil fertility challenges that reduce food production and if the practices can improve yield. We also decide based on whether the practice can increase the yield of beans, maize, or ground nuts”. Experts reported that they encouraged farmers to improve soil organic matter through various technologies, including manure application, mulching, crop residue incorporation, and agroforestry. The characteristics, methods, and successes of OMM applications vary with the OMM technology type as described below.

Manure application

From the expert interviews, it can be noted that the extension workers advised farmers to keep animals for a sustainable supply of manure. However, the farmers only prioritize particular crops e.g. bananas, which are considered for both food and cash. An example of this was noted among the farmers who participated in FGD1, 2019: “I have cows and I apply the farmyard manure into my banana plantation since bananas require a lot of nutrients. A plantation with manure will give many banana bunches[yield]. You know that is money [income] and food for my family”. The banana plantations were prioritized for FYM application because of the higher importance of economic and food values farmers derived from them in comparison to other crops. This finding was also supported by Nyombi et al. (2006). Manure such as farmyard manure could be adoptable by farmers as it does not require a constant application from season to season, as indicated in FGD2, 2019: “To our fields here, manure from livestock continues to supply nutrients even two years after application. So it is really a slow release that saves us from continuous application”. Similarly, farmers at an individual level basis acknowledged the benefit of farmyard manure concerning their prolonged contribution to soil fertility improvement. See the excerpt from Fi7: “Farmyard manure application gives me peace. As you know it, you do not need to apply it every season”. The extension workers had always encouraged farmers to apply FYM because almost all households owned at least one of the livestock types, such as cattle, goats, pigs, and chicken, even when reared in small numbers. The farmers without livestock were encouraged by the extension workers to obtain manure from their neighbors. Other farmers had adopted the use of slurry from pigsties and abattoirs to improve their soil. This case was noted in Ei3, 2019:

“The farmers mostly use FYM because it is accessible… we advise them to use FYM. However, we always discourage the use of artificial fertilizers because they are expensive. ... People’s kids [children] might even eat it. … People get slurry from either pigsties or abattoirs to create FYM”.

For farmers with limited access to dung for FYM production, the extension workers trained them in compost preparation and application. The training sessions were mainly on heap compost preparation methods as pointed out in Ei4, 2019: “… these days we encourage the compost that does not require the digging of holes because some farmers are lazy”. This could be an indicator that the adoption of compost depends on whether the farmers find its preparation process highly labor-requiring or not. Moreover, compost preparation was perceived as a highly labor-demanding practice by farmers in other African areas (Tibebe et al. 2022). Based on this, our results could imply that the pit compost preparation method is labor-intensive hence hindering adoption by smallholder farmers. The materials used by farmers in compost manure preparation include kitchen trash, grass, livestock dung, and water, as stated by Ei4, 2019. That same expert emphasized that compost manure that is prepared by combining FYM with other organic materials can improve soil nutrients more than the manure made from plant materials as a sole component. This could be explained by the high organic matter content that results from a combination of the materials used for manure preparation (Mamuye et al. 2021). In summary, the adoption of manure application into the field is influenced by its ability to improve yield and income, its accessibility, and the labor required to apply it, as also reported in other studies (Mamuye et al. 2021; Nyombi et al. 2006; Tibebe et al. 2022).

Crop residue incorporation

There was evidence of burning and ex-situ application of crop residues in the field. The academia and extension workers indicated that they had promoted in-situ CR management on farms. Moreover, the burning of crop residues was also highlighted in the FGD. “We burn the crop residues because they are bulky and can hide rats, which will eventually destroy our crops” (FGD1, 2019). The interviewed farmers and experts pointed out six main reasons why the farmers burn or carry away CR from the field. (i) Most annual crops such as beans, ground nuts, and maize are cultivated a distance away from homes while drying and shelling are done at home due to the limited capacity to construct processing and storage facilities in the field. In addition, farmers who transport harvested products from the field to their homes for processing find it laborious to carry the CR back to the fields for incorporation. (ii) The CR of some cereals such as maize have slow decomposition rates when they are not cut into smaller pieces. For this reason, some farmers transfer them to the perennial crop fields (especially banana and coffee) where they use them as mulch. Some of the farmers who only grow annual crops burn the CR either within the fields or at home where threshing is done. (iii) Some farmers burn bean and ground nut residues, as they believe that the residues deplete the soil of its nutrients. (iv) Burning of CR within the field has been one of the traditional practices conducted by farmers since time immemorial to improve soil nutrients. (v) Other farmers burn CR to get rid of stubborn weeds such as wandering jew (Commelina benghalensis) that might have been harvested along with the crops. (vi) The communities who use draught animals (ox) claim that the CR make it hard for the ox to till the land. However, literature shows that burning of CR can positively improve the soil nutrients but this positive impact is temporary as the nutrients released by burning can get lost through soil erosion or leaching (Gupta et al. 2004; Juo and Manu 1996). The results indicate that the practice of burning and carrying away of crop residues from the field by the farmers is a knowledge gap issue. Moreover, these practices have been blamed for encouraging nutrient mining in the fields where the residues were obtained (Ando et al. 2014; Ronner and Giller 2013; Tadele 2017).

It can be noted that the limited knowledge about the benefits and the techniques of crop residue management are the main factors responsible for the low adoption by smallholder farmers. These results were similar to what was documented in other studies (Raza et al. 2022; Mutwedu et al. 2022).

Mulching

Since soil erosion was one of the common challenges observed on smallholder farms, the experts advised farmers to mulch their fields, as one of the strategies for its control. Although some farmers were aware of the importance of mulching their fields, such activity was limited or not applied even among those declared as organic. “Even among some coffee farmers who claim that they produce [following the] organic [approach], the soils are bare and exposed to soil erosion. They are leaving their coffee to the mercy of God” (Ei1, 2019). Mulching was only common in vegetable and banana fields and the farmers used crop residues and dry grass (especially elephant grass). Mulching of annual cropland was not common on farms due to the unsystematic mixed cropping practices that make it hard for farmers to conduct mulching: “We would wish to mulch but how do we mulch a field with a mixture of beans, yams, maize, and bananas at the same time? It requires a lot of time” (FGD1, 2019). Other factors that limit farmers from adopting mulching include the high labor required to cut and transport the mulch material, and limited access to appropriate mulch material: “My household is willing to mulch all our fields but it requires a lot of labor as the grass can be obtained from the bush that is about a kilometer away from our land” (Fi9, 2019). This was also reflected within the FGD as shown in this case: “How do we mulch our fields when we can not access the mulch material? (FGD2, 2019). Other farmers claimed that the mulch material harbors rats and termites that end up damaging their crops. The extension workers mentioned that mulches can allow the growth of weeds that induce pathogens and diseases if not properly managed.

Generally, it can be seen that the adoption of mulching by smallholder farmers is limited by the accessibility of the mulch material, labor requirements to collect the mulch material, farmers prioritizing particular crops, and the limited knowledge of the proper agronomic practices. These factors are related to the results of other studies. In the northern part of Uganda for instance, the adoption of mulching is known to be limited by the competing uses of mulch material as livestock fodder and farmers’ fear of being bitten by poisonous snakes during the process of cutting the mulch material (Kaweesa et al. 2018). Level of education, land sizes, gender differences, land ownership, climatic conditions such as prolonged drought, and availability of funds to pay for mulch collection labor are among the factors influencing the adoption of mulching (Turyahabwe et al. 2022).

Agroforestry

There was evidence of farmers practicing agroforestry during field observations. Some farmers had a few scattered trees mainly Grevillea robusta on their farms. Other farmers had maintained a few scattered indigenous fruit trees such as mangoes, avocado, and jackfruit on their farms. To most farmers, the tree seedlings were availed by the NGOs and the extension workers. This improved access to tree seedlings by farmers who are located in remote areas that have financial challenges and limited technical knowledge to raise the tree seedlings. Consider this case: “In some cases, those officers from the government and other different organizations give us tree seedlings. This relieves us as we can not access the seeds. Most of us do not know how to raise the seedlings” (FGD1, 2019). It can be noted that the adoption of agroforestry on smallholder farms is limited by access to planting materials and techniques for raising trees. Access to planting materials and knowledge on how to raise the seedlings are among the factors considered important for enhancing the adoption of agroforestry in other parts of Uganda (Basamba et al. 2016).

Crop rotation

The integration of crop rotation in the field is influenced by the knowledge of the rotation system application. For instance, the farmers who had received a training in OMM had applied crop rotation principles on their fields while those without training were either practicing monocropping or rotating of only two crops. This is evidenced by the interviews and FGDs as seen in these two cases: “On this plot, I planted beans in the previous season, followed by maize in the last season. I intend to plant cassava when the rains begin” (Fi6, 2019). “We always plant cotton but if we want to change, we plant cotton in the August rains and maize in the March rains” (FGD2, 2019). This indicates that the implementation of crop rotation systems is influenced by knowledge of the farmer on how to conduct it. Knowldedge has also been reported as one of the factors that influence adoption of crop rotation in the East and West African farms (Tegene 2016).

From the nature of technology adoption component, it is evident that knowledge about the usefulness and how to apply technology, as well as the availability of labor and inputs are the main factors influencing the adoption of OMM. These factors have also been reported among farmers in other rural areas of Africa (Akinnifesi et al. 2010; Jha et al. 2021).

Farmer characteristics

From our results, we find that the adoption of some innovations is influenced by the farmers’ characteristics of age, education status, culture, and gender constraints. For instance, young farmers are more likely to adopt the OMM practices than the old ones since they can easily utilize training opportunities. Consider this example: “On my side, I used the knowledge I obtained from the training at the sub-county to plant diverse crops that can improve nutrition for my son and wife, and also provide fodder for our goats, which give us manure for our fields than depend on the bush burning practice that is practiced by families headed by men of my father’s age” (Fi4, 2019). In addition, a family with a household head who is not formally educated will follow cultural practices that are against OMM. This was exemplified in the FGD: “In this community, we learned all the farm management practices from our parents, which enabled millet to grow well from burnt fields” (FGD2, 2019). From the expert point of view, we noted that decision-making on issues related to soil fertility and OMM is majorly cultural and gender driven. This manifested in several ways, for example: “Most of the decisions are taken by men. The children are normally left out in decision making because the child has no access to land” (Ei2, 2019). The experts both academia and extension workers also expressed a need to integrate cultural and gender aspects into their implementation and/or development plans as they influence production-based decision-making processes. This case is noted from Ei9, 2020: “I picked one group per Sub-county where we train farmers with gender and cultural considerations. I have also included the organic soil fertility improvement measures in my financial plans”.

The farmer characteristics such as age, education status, culture, and gender are also reported in other studies as key in influencing the adoption of OMM practices (Kehinde and Shittu 2019; Usman et al. 2020).

Input-related adoption factors

The adoption of suitable OMM practices is influenced by several input-related factors. The factors mentioned by both the farmer (Fi2 and Fi3) and expert (E1, E3, and E5) interviewees include (i) the limited availability of planting materials of most of the leguminous tree species for implementing alley cropping, as manifested in farmer interviews. For example: “It is not easy to get those leguminous trees. If an organization was providing me with trees, I would plant them because trees will add fertilizer to my field” (Fi2, 2019); (ii) the limited availability of FYM as some farmers do not rear animals and some with animals practice free grazing or use the cow dung for other purposes, like house construction. This manifested in various ways, for example: “the availability of the planting material especially for the tree and the FYM is limited. The dung is smeared on houses …it is not that everybody has animals. … Most farmers have no fences and so the animals graze from communal land” (Ei3, 2019). Since inputs especially leguminous tree seedlings were not affordable to farmers, the experts suggested that the local governments include the planting materials in their development plans and budgets, so that they can avail such materials to the farmers. Consider this example: “Understandably, the tree seedlings may be inaccessible and unaffordable by the farmers. Every sub-county is expected to plan and budget for them. The farmers will plant them” (Ei1, 2019) (iii) To enhance the adoption of tree integration into farming systems, the experts and farmers suggested a strategy of tree nursery establishment and management at the sub-county to avail ready seedlings to the farmers and save them time and labor required for raising the seedlings. The following is a citation from one of the interviews: “Perhaps if that intervention is sought carefully at the sub-county, it can be adopted. We can procure the seed … put the seed in the nursery and raise the seedlings from the sub-county, then they are distributed to the interested farmers” (Ei2, 2019). Besides planting materials, labor was identified as another key challenge affecting the adoption of OMM practices by farmers as indicated by several experts, for example: “… one challenge is the labor requirements to deal with the organic matter because manure is bulky. If you are to do composting, you need a lot of labor” (Ei5, 2019). Moreover, the experts reported that some farmers had not adopted alley cropping due to the high labor costs for planting and weeding under the trees. Some farmers who use draught animals and tractors to till and weed land find it difficult to integrate trees on their farms as the trees make it difficult for land tilling with such technologies. For example:

“Another issue or challenge I am seeing is among the people who use draught animal technology. … it is common in Kamwenge and Kahunge sub-counties because for them they have vast land, so they use animals to plow. They are giving an excuse that the animals cannot plow where there are crop residues. Again, they do not want to meet the labor costs of removing the crop residues (Ei3, 2019). The use of draught animal technology in some communities is likely to hinder the adoption of alley cropping as plowing with such a technology is believed to cause damage to young trees. For instance: “If someone wants to use animals, he will say, I don’t want trees because they will interfere with the plow which will eventually cut them” (Ei5, 2019).

Inputs play a vital role in enabling the adoption of OMM practices. In this particular case, the availability and affordability of inputs such as tree seedlings and manure, and the labor requirements to apply the inputs into the field were the important factors influencing the adoption of OMM practices. These input-related adoption factors were also reported in other studies (Ndambi et al. 2019; Basamba et al. 2016; Tibebe et al. 2022).

Institutional-related adoption factors

From the farmers’ point of view, it can be seen that policy formulation and implementation can improve the adoption of OMM practices as pointed out by one of the farmers who participated in the FGD2, 2019): “In our area? I do not think that all farmers can plant trees or mulch their fields without any force from the sub-county. Formulation and implementation of the policies can change a lot”. The experts mentioned that the farming systems in the Rwenzori region have been faced with governance-related challenges. These include poor agricultural-related policy implementation, low prices for agricultural commodities, no state-owned production associations and only some farmer production groups existed. These challenges can be solved in various ways as suggested by the experts. (i) The implementation of sustainable agriculture-related policies in Uganda that would enable local governments to develop ordinances and bylaws, which when enforced, many farmers would adopt the appropriate OMM practices. Moreover, policy enforcement had ever enhanced the adoption of the terraces that exist in the Kigezi region of Western Uganda (Carswell 2006). (ii) Establishment of a system where subsidies and premium prices are placed on organically produced food to compete fairly with food produced through conventional practices. This would motivate farmers who apply OMM practices and enhance adoption among those without such practices on their farms. (iii) Facilitating farmers to form state-owned OMM associations at district and national levels that would force the state to set aside funds for supporting the farmers. (iv) Encouraging farmers to form food production groups, which would aid extension workers in the demonstration and monitoring of the OMM practices being implemented. On the side of the farmers, food production groups would increase learning and opportunities to revolve labor hence minimizing labor costs. One opportunity for this is the existence of academic institutions such as MMU and Uganda Martyrs University in the region, with programs for teaching and demonstrating OMM-related practices to students. This is exemplified in the following:

“This demonstration farm is set up in such a way to mimic a sustainable smallholder farm. We have a farm plan and have established a homestead with the poultry, goat, rabbit, and cattle structures arranged in such a way as to ensure the recycling of kitchen refuse and manure from livestock. The livestock feed on the vegetation planted along the soil and water conservation structures” (Ei8, 2020).

Ten more agroecology demonstration farms were developed at the community level in the Rwenzori region. These farms aimed to enable students to appreciate the real-life challenges that exist in communities and provide them with an opportunity to work with farmers in developing localized solutions to such challenges, following a wide system thinking approach.

“Since our program is aimed at producing graduates who are practical-oriented, we have developed community agroecology demonstration farms in each of the districts of Kabarole, Kasese, Kyenjojo, and Bundibugyo. These farms are expected to aid knowledge co-creation between farmers and students. … we have trained farmer groups in proper land use planning and integration of activities such as mulching, cover cropping, alley cropping, and crop rotations” (Ei10, 2020).

(v) Involving political leaders both at district and sub-county levels in the implementation of OMM activities would enhance adoption by the communities as they are considered more influential with ability to lobby funds from government than the technical people. (vi) To enhance farmer adoption, all projects related to OMM need to be declared as non-political as some political parties are regarded as egocentric. Another hindrance to the adoption of the OMM practices that was pointed out by experts is related to the conflicting implementation strategies by some stakeholders: “… the people supplying chemicals are doing us an injustice, and they are making most of our interventions fail to work. So we need joint concepts” (Ei2, 2019). To enhance OMM-related information flow, a multidisciplinary consortium comprising representatives from farmer groups, technical experts, academia, political leaders, input dealers, and marketing groups was suggested by the experts.

The role of institutions in motivating and penalizing adopters and non-adopters respectively is fundamental in enabling the adoption of OMM practices. This will be cushioned by institutions that provide knowledge and practical experience in implementing OMM practices on smallholder farms. Similar results have been reported in other studies (Carswell 2006; Nazari and Hasbullah 2010; Ndambi et al. 2019).

Information transfer-related adoption factors

The information flow gap between the experts and the farmers came out during interviews as a factor influencing the adoption of OMM practices. Consider this case: “Those government workers [extension workers] can reach us once in about five years. They only meet those growing coffee. Moreover, even when they come, they never talk about OM but rather fertilizers from the shop” (FDG2, 2019). From the expert point of view, it can be noted that information flow is limited by low extension worker staffing rate and limited transport facilitation to enable them to reach all the farmers. The case in a point is noted by Ei6, 2019: “… of course they [Extension workers] are few, at the same time, the recommended extension worker to farmer ratio is 1: 500. For us we are at 1 extension worker: 1800 farmers. The interaction is low … You know when you have a sub-county of over 1000 farmers and you do not have a motorcycle, it also becomes a problem”. This is a big challenge since the use of extension workers to avail information to farmers has been documented as a sustainable approach for enhancing adoption (Ndambi et al. 2019). To overcome those challenges, the experts developed a strategy of sensitizing farmers via radios. Radio programs have also been organized for the academia to disseminate their research findings and for the farmers to share their lessons related to food production. Radio programs could be a sustainable approach for increasing awareness about OMM as it has been documented as one of the best approaches for educating and increasing knowledge in agricultural interventions among farmers (Nazari and Hasbullah 2010). Additionally, the majority of the people in Uganda listen to the radio (BBC 2019). However, these radio sessions do not compensate for the field practical demonstrations but are simply an addition.

There are four major sustainable strategies for enhancing information flow as raised by the interviewed experts and farmers. These include: (i) organizing sensitization and training sessions that are based on calculations of profits and cost–benefit analysis of the different OMM practices. This would bring out a clear picture of the benefits of OMM implementation hence enhancing adoption. Such an approach is possible for smallholder farmers if the extension workers are facilitated to package and transfer such kind of information to the farmers. (ii) Setting up demonstration farms at parish and village levels would enhance field practicals and ease the dissemination of information to farmers living in remote areas. Demonstrations have been regarded as viable for solving barriers to the adoption of sustainable agricultural practices, including OMM (Rodriguez et al. 2009). These are likely to encourage farmers to participate and learn by doing. The participatory or learning-by-doing approach has been reported to improve learning and enable the development of site-specific innovations (Sánchez‐Reparaz et al. 2020), hence enhancing the adoption of locally developed strategies. (iii) The training and demonstrations should be based on indigenous knowledge, as farmers possess vast knowledge in planning for their fields. When the expert knowledge builds on indigenous knowledge, both the experts and farmers are likely to gain the confidence to develop harmonized innovative strategies that are adoptable by farmers. (iv) Formation and use of stakeholder consortia for harmonized implementation strategy of the OMM practices on smallholder farms hence avoiding duplication of implementation strategies by different stakeholders. Such consortia can also provide a platform for a common understanding of solutions to community challenges and result in the proper utilization of resources. Besides, consortia are documented for augmenting innovation development (Hermans et al. 2017).

Under the information transfer-related factors that influence the adoption of OMM, participatory practical exchange of knowledge between farmer advisors and local knowledge enables adoption. The same factors have also been reported in other studies as key to the adoption of practices by farmers (Ndambi et al. 2019; Rodriguez et al. 2009: Sánchez‐Reparaz et al. 2020).

Conclusion

This study applied a hybrid theoretical framework, which purports: the adoption process of a practice can be facilitated if farmer characteristics and the institutional related factors can support it; information about the practice and the required inputs are available, and he/she can apply the required technology with ease. This hybrid theoretical framework was developed following three theories: the Theory of Planned Behavior, the Technology Acceptance Model, and the Rural Technology Acceptance Model to understand the factors influencing the adoption of OMM practices by smallholder farmers. Some of the key OMM practices on smallholder farms included manure application, mulching, crop residue incorporation, and agroforestry. Our study showed that the farmer characteristics such as age, education status, gender, culture, and knowledge about the use and application of a practice; availability of labor and inputs; availability of appropriate equipment; adequate information from the extension staff, the existence of supportive policy framework and presence of social support are the main factors influencing adoption of OMM practices on smallholder farms. These factors can be categorized as technical, social, cultural, and political. The factors cut cross among the five adoption components: farmer characteristics, information transfer-related adoption factors, input-related adoption factors, institutional-related adoption factors, and the nature of the technology. All these factors are implied in the hybridized theoretical framework and it can be applied by extension workers as a model to improve soil organic matter and nutrient recycling. These study findings are of relevance to decision makers to guide investment decisions. A follow-up study where this model is tested for its feasibility is recommended before experts can apply it in developing strategies for the adoption of OMM practices on smallholder farms. Moreover, the development of this model was informed by primary data from three out of six main cultural groups of the Rwenzori and yet the findings show that culture is an important adoption factor. Further studies should include farmers of other cultures to capture all the factors that influence adoption of OMM in the Rwenzori region.