1. INTRODUCTION
1.1. Background to the Study
Sustainable agriculture in Kenya has gained increasing attention as farmers confront declining soil fertility, unpredictable rainfall patterns, and rising production costs. Over several decades, continuous cultivation, erosion, and intensive reliance on synthetic fertilizers have contributed to the depletion of soil organic matter and reduced resilience of farming systems. This trend threatens national food security, especially among smallholder farmers who produce over 70% of Kenya’s food crops. Regenerative agriculture, which emphasizes soil restoration, minimal disturbance, and increased biological activity, has emerged as a timely response to these challenges. As part of regenerative practices, compost and organic manure offer an effective, affordable, and environmentally sound pathway for replenishing soils while enhancing long-term productivity.
1.2. Statement of the Problem
Despite the known benefits of regenerative agriculture, Kenyan farmers still face significant soil degradation and nutrient depletion, with many regions reporting declining crop yields and reduced soil structure. Synthetic fertilizers, although effective in the short term, are expensive and often inaccessible to resource-limited communities. Additionally, their misuse can lead to soil acidity, nutrient imbalance, and environmental pollution. A major gap persists in the adoption of composting and organic manure as sustainable alternatives. Many farmers lack technical knowledge on compost preparation, quality control, and proper application rates, while others perceive the process as labor-intensive or slow. These constraints highlight the need for a scientific analysis that demonstrates practical composting techniques and their regenerative potential under Kenyan farming conditions.
1.3. Purpose of the Research
The purpose of this research is to provide a comprehensive scientific and practical understanding of how compost and organic manure can be produced and applied to support regenerative farming in Kenya. The study explores suitable composting methods for Kenyan agroecological zones, evaluates their agronomic benefits, and assesses the potential of organic manure in reversing soil degradation. It also examines challenges farmers encounter during production and application, and identifies strategies that can support widespread adoption. Ultimately, the research aims to empower farmers, extension officers, and policymakers with evidence-based insights that enhance soil health, strengthen climate resilience, and promote sustainable agricultural systems capable of supporting current and future generations.
1.4. Research Questions
This study is guided by five key research questions: (1) Which composting methods are most effective and practical for Kenyan farmers? (2) What forms of organic manure are most suitable and accessible across Kenya’s diverse agricultural landscapes? (3) How does the application of compost and organic manure influence soil health parameters such as structure, nutrient content, and microbial activity? (4) What socio-economic and technical challenges limit the adoption of compost-based regenerative farming? (5) Which best-practice strategies can strengthen adoption and scale regenerative soil fertility management in Kenya? These questions form the foundation for the methodological approach and guide the analysis of both qualitative and quantitative findings.
1.5. Objectives of the Study
The general objective of this study is to investigate the effectiveness and practicality of compost and organic manure as regenerative soil nutrients for sustainable crop production. The specific objectives are: (a) to review the principles and biological processes involved in composting; (b) to document compost production techniques used in Kenya; (c) to analyze the effects of organic manure on soil physical, chemical, and biological properties; (d) to identify challenges faced by farmers in adopting compost-based fertility management; and (e) to provide best-practice recommendations and strategies for scaling regenerative agriculture. These objectives ensure a comprehensive exploration of composting as both a scientific process and a practical on-farm strategy for soil rehabilitation.
1.6. Significance of the Study
This research is significant for several reasons. For farmers, it offers practical, cost-effective solutions for improving soil fertility and reducing dependence on costly synthetic fertilizers. For extension workers, it provides scientifically grounded guidance that can inform training programs and field demonstrations. Policymakers benefit from evidence that supports the integration of regenerative soil health approaches into national agricultural frameworks. Academic institutions and researchers also gain data that contributes to ongoing efforts to enhance sustainable food production in East Africa. More broadly, promoting compost and organic manure strengthens ecological resilience by enhancing carbon sequestration, reducing waste, and improving biodiversity—elements essential for long-term agricultural sustainability in Kenya.
1.7. Scope and Limitations
This study focuses on composting and the use of organic manure in Kenyan smallholder farming systems. The scope includes compost types, production techniques, and regenerative soil benefits across Kenya’s major agroecological zones. However, the research has limitations, including regional variability in organic materials, climatic differences that influence composting rates, and disparities in farmer knowledge and resource availability. Additionally, nutrient content of compost may vary significantly depending on feedstock, which affects consistency in data interpretation. While the study provides generalizable insights, field-specific variations may require localized adaptation. Nevertheless, the research offers a strong foundation for understanding compost’s role in regenerative agriculture within Kenya.
2. PRINCIPLES AND SCIENCE OF COMPOSTING & ORGANIC MANURE
2.1. Overview of Organic Manure
Organic manure refers to natural plant and animal-based materials applied to soil to enhance fertility and improve physical, chemical, and biological properties. Unlike synthetic fertilizers, which deliver nutrients in concentrated forms, organic manure offers slow-release nutrients while simultaneously improving soil structure, moisture retention, and microbial life. Common types include farmyard manure (a mixture of animal waste and bedding), compost (decomposed organic matter), green manure (fresh plant material ploughed into soil), and vermicompost (earthworm-processed organic waste). In Kenyan agricultural systems, these materials are particularly valuable due to their affordability and availability from household, livestock, and crop residues. Organic manure aligns well with regenerative farming principles because it enhances long-term soil health rather than providing temporary nutrient boosts.
2.2. Biological Processes of Composting
Composting is fundamentally a biological process driven by microorganisms, including bacteria, fungi, and actinomycetes. These organisms decompose organic materials through successive phases: an initial mesophilic phase, where moderate temperatures activate microbial decomposition; a thermophilic phase, where temperatures rise to above 55°C, ensuring rapid breakdown and destruction of harmful pathogens and weed seeds; and a cooling/maturation phase where materials stabilize into humus-like compounds. Microbial activity depends on adequate aeration, moisture, and the correct carbon-to-nitrogen ratio. During decomposition, microorganisms transform raw organic matter into stable organic compounds that improve soil structure and nutrient cycling. This controlled biological breakdown is central to producing high-quality compost capable of regenerating degraded soils across Kenya.
2.3. Chemical Dynamics in Composting
Composting involves a series of chemical transformations influenced by temperature, microbial activity, and the types of materials used. One of the most critical chemical parameters is the carbon-to-nitrogen (C:N) ratio, ideally between 25:1 and 30:1, which ensures efficient microbial activity without causing nitrogen losses through volatilization. As decomposition proceeds, carbon is released as carbon dioxide while nitrogen becomes increasingly concentrated in more stable organic forms. Additionally, the pH of compost tends to rise during the thermophilic stage and stabilize during curing, providing a balanced medium for application to soils. Nutrient mineralization during composting leads to the formation of plant-available nitrogen, phosphorus, and potassium, although the slow-release nature minimizes leaching losses common with synthetic fertilizers.
2.4. Types of Raw Materials and Additives
Composting requires a balanced mixture of carbon-rich “brown” materials and nitrogen-rich “green” materials. Browns include dry leaves, maize stalks, straw, sawdust, and shredded paper—materials that provide structural stability and energy for microbial respiration. Greens consist of fresh grass clippings, kitchen waste, animal manure, and green vegetation, supplying proteins and nitrogen necessary for rapid microbial multiplication. Additives such as wood ash (providing potassium), rock phosphate (boosting phosphorus levels), and locally available biofertilizer inoculants can enhance the nutrient content and speed of decomposition. Kenyan farmers often utilize locally accessible materials, making compost an affordable and context-appropriate soil fertility amendment for regenerative farming.
2.5. Environmental and Health Safety Considerations
Safe composting is essential to ensure the final product is free from pathogens, toxins, or chemical contaminants. During the thermophilic phase, temperatures above 55°C destroy most harmful organisms, livestock parasites, and weed seeds, making compost safer than raw manure. Proper handling is necessary to prevent contamination from plastics, metals, or chemical residues often found in household waste. In addition, the compost must be adequately cured to stabilize nutrients and minimize risks of ammonia burn when applied to young plants. By following proper safety standards, compost production contributes to improved public health, reduced landfill waste, and enhanced environmental sustainability—key aspects of regenerative agricultural systems.
3. COMPOST PRODUCTION METHODS SUITABLE FOR KENYA
3.1. On-Farm Heap/Stack Composting
Heap composting is one of the most widely used methods among Kenyan farmers due to its simplicity and minimal resource requirements. The technique involves forming a layered pile with alternating carbon-rich and nitrogen-rich materials, including crop residues, fresh vegetation, manure, and soil. A typical heap measures about 1.5 meters high and 1 meter wide, ensuring sufficient aeration while retaining moisture. Turning is recommended every 7–14 days to maintain oxygen supply and improve microbial activity. Farmers monitor moisture by checking that the heap feels moist but not soggy. Under optimal conditions, decomposition takes 6–12 weeks, producing a dark, crumbly, and nutrient-rich compost suitable for use in crop fields, gardens, and orchards.
3.2. Pit Composting
Pit composting is popular in arid and semi-arid regions of Kenya because it minimizes moisture loss and protects compost materials from wind and excessive heat. Farmers dig pits approximately 1–2 meters long, 1 meter wide, and 0.5–1 meter deep, then fill them with alternating layers of organic materials. While the method conserves moisture more effectively than heap composting, it sometimes limits aeration, slowing decomposition unless the pit is turned or aeration channels are included. Despite this limitation, pit composting is particularly advantageous for farmers who have limited biomass or live in areas with prolonged dry seasons. Maturation typically takes three to four months, producing a stable compost with improved water retention properties beneficial for soil restoration.
3.3. Vermicomposting
Vermicomposting involves the use of earthworms—commonly red wigglers—to process organic waste into highly nutrient-rich vermicast and vermiliquid. The worms feed on decomposed organic matter, accelerating breakdown and enhancing nutrient availability. Vermicompost contains higher concentrations of nitrogen, phosphorus, potassium, and beneficial microbes compared to ordinary compost. In Kenya, vermicomposting is gaining popularity among vegetable growers and peri-urban farmers due to its fast decomposition rate and high-quality output. The method requires shaded, moist environments and consistent feeding using kitchen waste, manure, or chopped plant residues. When properly managed, vermicompost production takes 4–8 weeks and offers an efficient method for regenerating degraded soils and supporting high-value crop production.
3.4. Integration of Green Manure
Green manure involves growing specific plant species—often legumes such as sunn hemp, desmodium, crotalaria, and lablab—and incorporating them into the soil while still green and nutrient-dense. These plants fix atmospheric nitrogen through symbiotic bacteria, enriching soils naturally. In Kenyan farming systems, green manures are beneficial for suppressing weeds, enhancing soil cover, reducing erosion, and improving organic matter levels. Their integration into crop rotations, particularly maize–bean or vegetable systems, enhances soil structure and boosts microbial activity. Green manure complements composting by providing fresh biomass that boosts compost nitrogen content and accelerates decomposition, making it an important regenerative farming practice.
3.5. Enhanced or Accelerated Composting
Enhanced composting involves adding biofertilizer inoculants, effective microorganisms (EM), or compost accelerators to speed decomposition and improve nutrient content. Farmers may also use rock phosphate or ash to correct nutrient imbalances and improve phosphorus and potassium availability. This method is especially valuable in high-altitude Kenyan regions where low temperatures slow down microbial activity. By increasing the diversity and population of beneficial microorganisms, enhanced composting improves compost quality, reduces decomposition time, and strengthens soil microbial ecosystems when applied. Although the inputs may slightly increase production costs, the benefits to nutrient cycling, soil fertility, and crop productivity make it a viable strategy for regenerative agriculture.
3.6. Quality Assessment and Maturity Testing
Ensuring compost quality is essential for achieving optimal results in regenerative farming. Mature compost is dark, crumbly, and emits an earthy smell. It should not be hot or produce ammonia odors, which indicate incomplete decomposition. Simple tests, such as the germination test, can determine whether compost contains harmful residues that inhibit plant growth. Farmers may also perform a jar test to assess particle balance or consult laboratories for nutrient analysis when resources allow. Compost that meets maturity standards delivers consistent benefits, including improved soil structure, enhanced microbial activity, and slow-release nutrients that crops can readily absorb. Proper quality assessment ensures compost is safe, effective, and reliable for field application.
4. EFFECTS OF COMPOST & ORGANIC MANURE ON SOIL HEALTH AND CROP PERFORMANCE
4.1. Physical Effects on Soil
Compost plays a vital role in improving soil physical properties, particularly in regions where continuous cropping and erosion have degraded soil structure. When incorporated into soil, compost enhances aggregation, creating stable soil particles that improve aeration and water infiltration. This enhanced structure reduces compaction, increases root penetration, and supports better root development. Additionally, compost boosts water-holding capacity, especially in sandy soils common in coastal and eastern Kenya, helping crops withstand dry spells. For clay soils, compost improves porosity, reducing waterlogging and crusting. These improvements in soil physical quality contribute to more resilient and productive cropping systems, which are central to regenerative agriculture.
4.2. Chemical Effects of Compost Application
Compost enhances soil chemical properties by increasing soil organic matter, improving cation exchange capacity (CEC), and supplying essential nutrients such as nitrogen, phosphorus, potassium, calcium, and magnesium. Unlike synthetic fertilizers, which release nutrients rapidly, compost provides a slow-release nutrient system that matches plant demand and reduces nutrient leaching. Compost also buffers soil pH, making acidic or alkaline soils more favorable for crop growth. In areas where soil acidity is a major constraint—such as Central and Western Kenya—compost reduces aluminum toxicity and enhances phosphorus availability. These chemical improvements promote balanced nutrient uptake and contribute to stronger crop performance across diverse agroecological zones.
4.3. Biological Benefits to Soil Ecosystems
The biological benefits of compost are among the most significant contributors to regenerative farming. Compost increases microbial diversity by supplying organic substrates that fuel microbial growth. Beneficial microorganisms—including nitrogen fixers, phosphorus solubilizers, and decomposing fungi—thrive in compost-rich soils. These organisms enhance nutrient cycling, suppress soil-borne diseases, and foster symbiotic relationships between plants and microbes. Compost also increases earthworm populations, which help aerate soil, enhance nutrient availability, and accelerate the breakdown of organic residues. A biologically active soil is more resilient, supports more vigorous crops, and recovers more quickly from environmental stress, all of which are essential for sustainable farming systems in Kenya.
4.4. Effects on Crop Yield and Performance
Numerous studies and farmer experiences across Kenya show that compost significantly improves crop yields, particularly when combined with good agronomic practices such as mulching and crop rotation. For maize and beans—the most widely grown crops—compost enhances root development, nutrient availability, and moisture retention, leading to higher biomass and grain yields. In vegetable production, compost improves soil texture and nutrient balance, resulting in larger, healthier, and more marketable produce. Compost is especially beneficial in organic and low-input systems where synthetic fertilizers are unaffordable. While yield increases may vary by region and crop type, the consistency of positive outcomes supports compost adoption as a key regenerative farming strategy.
4.5. Environmental Benefits
Compost application contributes significantly to environmental sustainability, making it a cornerstone of regenerative agriculture. By recycling organic waste from households, markets, and farms, composting reduces landfill accumulation and prevents burning of crop residues, which contributes to air pollution. Compost enhances carbon sequestration by increasing soil organic matter, helping mitigate climate change. It also reduces nutrient runoff into water bodies, lowering risks of eutrophication compared to synthetic fertilizers. Additionally, compost encourages biodiversity above and below the soil surface, supporting balanced ecosystems. These environmental benefits ensure that compost-based systems provide not only agricultural productivity but also long-term ecological stability.
5. CHALLENGES & LIMITATIONS IN ADOPTION OF ORGANIC MANURE AND COMPOSTING
5.1. Labour, Time and Resource Constraints
Although composting and organic manure production offer long-term benefits, many smallholder farmers in Kenya report that the labour and time required present a major barrier. The process involves collection of crop residues, animal manure, green waste or kitchen waste; layering or mixing; regular turning; moisture monitoring; and waiting for decomposition/maturation. For many households — especially those relying on manual labour and with limited household members — these steps are onerous. Surveys in Kenya’s smallholder communities show that labour shortage is often cited as the main constraint: some studies report that over 80% of farmers using compost composting mention labour requirement as a major barrier. (UoN eRepository)
Moreover, the time to produce mature, stable compost (which may range from several weeks to months, depending on materials, climate, and method) is longer than the immediate effect of synthetic fertilizers. For resource-constrained farmers seeking quick yield response, this delay reduces the attractiveness of composting. The inconsistency in raw material availability — for example during dry seasons or when crop residues are sold or used for other purposes — further complicates efforts. (NFP Connects)
5.2. Availability and Quality of Raw Materials
A critical limitation to effective composting is the availability of sufficient and appropriate raw materials. Many small farms have limited biomass — for instance, few livestock to supply manure, minimal crop residue, or insufficient household organic waste — which makes achieving the optimal carbon-to-nitrogen balance difficult. Some farmers may resort to mixing suboptimal materials, leading to compost that is nutrient-poor or decomposes slowly. (UoN eRepository)
Quality variability is another serious issue. Without proper knowledge of composting science — such as correct layering, moisture control, aeration, and turning — compost may remain immature, have poor structure, or fail to destroy pathogens. Such poor-quality compost can lead to low crop performance, discouraging further adoption. Reports from Kenyan farmer groups highlight inconsistent compost quality as a deterrent to widespread use. (Agric4Profits)
5.3. Technical Knowledge Gaps and Limited Extension/Support Services
A significant barrier is the lack of technical knowledge among many farmers about composting practices. Many have limited awareness of key parameters — for example, the importance of carbon-to-nitrogen ratio, turning frequency, moisture management, or maturity testing. In surveys across Kenyan agroecologies, a considerable proportion of farmers reported not knowing how to effectively produce or apply compost. (Frontiers)
Moreover, extension services and institutional support for organic farming remain weak in many areas. Research and training have historically prioritized conventional agriculture, so fewer institutions emphasize composting methods or regenerative practices. This lack of training, demonstration plots, or support systems reduces farmers’ confidence to invest time and labour into compost production. (CORE)
5.4. Economic, Market, and Institutional Barriers
Even where compost is produced, economic and market limitations can hinder its effective use or expansion. For community-based compost producers or cooperatives, challenges include lack of capital for equipment, poor transport infrastructure for bulky compost, and lack of stable demand/market for the end product. In urban/peri-urban composting initiatives, lack of secure land tenure or appropriate sites has undermined long-term operations. (doczz.net)
Additionally, in many regions, transitioning to fully organic or compost-based systems may involve a short-term drop in yield — because soil fertility rebuilds gradually over time. This yield lag can make farmers hesitant to adopt compost-based methods, especially if they rely on consistent harvests for subsistence or income. (farmersguide.co.ke)
Institutional barriers also include limited policy support for organic agriculture, minimal subsidies or incentives for composting, and few programs promoting compost markets or distribution. Organic agriculture remains a small sub-sector in Kenya, in part because of inadequate research, training, regulation, and support frameworks. (repository.kippra.or.ke)
5.5. Socio-economic and Demographic Constraints
Adoption of compost and organic-manure-based agriculture is influenced by socio–demographic factors. Studies have found that small farm size, land tenure insecurity, household labour availability, and age of the household head all affect whether farmers engage in composting. For example, older household heads or those with small plots often avoid labour-intensive composting practices. (Frontiers)
Moreover, households with fewer members or minimal livestock may not generate enough organic waste to justify the effort. When crop residues are used for fodder or sold for income, available biomass for composting further reduces. Additionally, in areas far from homesteads, transport of residues or manure to the compost site can be difficult, discouraging adoption. (UoN eRepository)
These socio-economic dynamics mean that composting often remains limited to households that already have livestock or sufficient labour, reducing the potential for widespread adoption across all smallholders.
6. BEST PRACTICES & IMPLEMENTATION STRATEGIES FOR REGENERATIVE FARMING WITH ORGANIC MANURE IN KENYA
6.1. Integrating Compost/Organic Manure into Farming Systems
For compost and organic manure to deliver long-term benefits, they must be integrated within broader regenerative farming systems — including crop rotation, minimal tillage, mulching, cover cropping, and agroforestry. Combining compost application with cover crops or green manures in a rotation (e.g., cereals with legumes) helps replenish soil nitrogen, break pest/disease cycles, and enhance organic matter. This integrated approach builds resilience and improves soil fertility over seasons, rather than relying solely on compost as a “fix.” Such holistic systems align well with the regenerative agriculture paradigm and are increasingly advocated across East Africa. (ke.boell.org)
6.2. Use of Enriched or Enhanced Compost for Nutrient Balance
Given that compost made from typical farm waste may have limited concentrations of certain nutrients (especially phosphorus and potassium), best practices encourage enrichment of compost using locally available mineral additives (e.g., rock phosphate, wood ash) or biofertilizer inoculants. Enrichment improves the nutrient density and ensures balanced nutrition for crops over time. Where possible, blending compost with small amounts of mineral fertilizer (“integrated fertilization”) can help meet immediate nutrient demands while building long-term soil organic matter. This combination is especially useful in soils with known nutrient deficiencies.
6.3. Quality Control, Maturity Testing, and Proper Application Rates
To ensure compost effectiveness and avoid negative effects (e.g., nutrient imbalance, ammonia burn, pathogens), farmers should adopt quality control measures: maturity testing (e.g., odor test, texture, germination test), proper curing, and perhaps (where possible) simple nutrient analyses. When applying compost, recommended rates should consider soil type, crop type, and available compost volume. For example, applying compost before planting or during land preparation ensures good mixing with soil; for vegetables or high-value crops, compost can be applied in planting holes or as side-dressing for continuous nutrient supply. Proper application maximizes benefits to soil structure, nutrient availability, and crop yield.
6.4. Community-level and Cooperative Composting, and Shared-resource Models
Recognizing that many smallholder farms lack sufficient raw materials or labor individually, community-based composting offers a viable strategy. Farmers’ groups or cooperatives can pool resources (crop residues, livestock manure, labour) and produce compost at scale for shared use or sale. Such models can reduce individual burden, improve efficiency, and create local compost markets. Establishing community composting centers near villages can also help manage organic waste (household, market, farm) and promote circular resource use. Encouraging institutional support, training, and simple tools (e.g., compost turners, shredders) can significantly enhance such communal approaches.
6.5. Extension Services, Capacity Building, and Policy Support
For wide-scale adoption of compost-based regenerative farming, there is a need for strengthened extension services and training programs that teach composting methods, quality control, and integrated soil fertility management. Research institutions, NGOs, and government agencies must collaborate to demonstrate composting techniques, conduct field trials, and share success stories — especially in local languages and context-specific agroecologies. Policy support is also critical: subsidies or incentives for compost production, inclusion of organic fertilization in national soil fertility guidelines, and support for community composting infrastructure can accelerate adoption.
7. CONCLUSION
In conclusion, compost and organic manure represent a powerful, sustainable pathway for regenerating soil health and improving agricultural productivity across Kenya. When properly produced and applied, organic amendments enhance soil structure, water retention, microbial activity, and nutrient availability — yielding long-term benefits that synthetic fertilizers alone cannot deliver. However, significant challenges remain: labour intensiveness, material scarcity, variability in compost quality, limited technical know-how, and weak institutional support all hinder widespread adoption. Addressing these challenges requires a multi-pronged approach: promoting integrated farming systems, enriching compost, ensuring quality control, building community-level composting models, and strengthening extension services and policy backing.
With sustained effort, knowledge dissemination, and institutional support, compost-based regenerative farming can become a viable, scalable, and environmentally sustainable agriculture model for Kenya — benefiting smallholder farmers, improving food security, and contributing to climate resilience.