The scale of Ghana’s cocoa economy makes the findings significant far beyond the farm gate. Around 71 percent of the world’s cocoa is grown in West Africa, with Ghana the second largest producer after Côte d’Ivoire. An estimated 800,000 Ghanaian farmers cultivate cocoa on plots typically smaller than five hectares, and the crop contributes roughly 22 percent of the country’s agricultural GDP, employs about 45 percent of the population, and accounts for nearly half of all export earnings. Yet productivity per hectare has barely improved over the past decade. Historic gains in national output have come mostly from clearing more land, not from growing more beans per hectare, a pattern repeated across the region.

The technical picture behind stagnant yields is well understood. Continuous cropping has depleted soil organic matter, and yields between individual farms vary enormously, from roughly 100 to more than 1,000 kilograms per hectare, with agronomic management a major determinant of the gap. Surveys of soils in Ghana’s cocoa districts reveal low organic matter and low pH, consistent with a boom-bust cycle in which cultivation mines the soil of nutrients. Chemical fertilisers, the default remedy, bring problems of their own: they acidify soils, reducing the availability and uptake of nutrients, they can pollute surface waters, and their price puts the quantities farmers actually need beyond their reach. Most of the surveyed farmers relied on subsidised fertiliser from the Ghana Cocoa Board, but complained that supplies were inadequate and arrived late.

Organic amendments offer a technically elegant alternative. Compost supplies plant nutrients, rebuilds soil organic matter, improves structure, boosts microbial activity, and can even suppress nematode pests in cocoa farms. Biochar, produced by burning organic material in the absence of oxygen through pyrolysis, is a highly recalcitrant form of carbon that improves soil structure, increases water-holding capacity, and alleviates the soil acidity that chemical fertilisers worsen. Crucially, both can be made from cocoa pod husks, the fibrous shells left behind after the beans are extracted, which pile up on farms as waste. The husks are rich in phosphorus and potassium, and studies in Nigeria have shown that pod-husk fertiliser can lower costs and raise revenues on cocoa farms. Composting the husks has also been shown to suppress the Phytophthora pathogen responsible for black pod disease.

To find out why farmers were not exploiting this resource, researchers from Kwame Nkrumah University of Science and Technology, the Cocoa Research Institute of Ghana, and the University of Reading surveyed 150 farmers randomly drawn from a population of 245 across five cocoa districts representing four soil types and all five major agroecological cocoa regions of Ghana. The districts, Aiyinase, Assin Foso, Dadiesoaba, Kade, and Nyarkrom, were selected using a soil map to ensure that Ferralsols, Lixisols, Nitosols, and Acrisols were all represented, since amendments may perform differently on different soils. A follow-up focus group of eight experienced farmers and cooperative leaders helped interpret the survey answers. The team is careful to note that participants were all already working with Cocoa Extension Agents, so the results describe engaged farmers rather than the most isolated growers.

The demographic profile that emerged is one of experienced but ageing farmers under real economic pressure. Respondents averaged 51 years old, with 16 years of cocoa experience on average, and three quarters had additional income sources, mostly petty trading, because cocoa alone could not sustain their households. One farmer told the focus group bluntly that the money from cocoa was inadequate for his family to survive a year. About 67 percent of farmers reported that soil fertility had declined over the years, and 92 percent said they could identify poor soil by signs such as unhealthy leaves, wilted pods, small beans, and falling yields. Yet when asked about organic amendments, only 6 percent had ever used any, and those cases turned out to be poultry manure, not compost or biochar.

The awareness gap was stark and, in places, almost comic. Nearly half the farmers had heard of compost, but overwhelmingly as a technique for growing vegetables, not cocoa, a legacy of alternative-livelihood training programmes run by COCOBOD and NGOs. Only 12.7 percent of those aware of compost knew how to make it. Biochar fared far worse: 97.4 percent had never heard of it, and none had any knowledge of how to prepare it. What makes the result remarkable is what happened when the concept was explained. Ninety-six percent of farmers unfamiliar with compost said they were willing to learn to make it, and 76 percent were willing to buy it, quoting an average price of 26.33 Ghana Cedis for a 25-kilogram bag. For biochar, 96 percent were willing to learn and 77 percent willing to buy. As one farmer put it, there is no market in Ghana where organic fertiliser can be purchased at all, even though national demand is estimated at 0.7 million tonnes per year and could rise to 2.7 million tonnes.

The study also uncovered a dangerous misconception. Farmers feared that spreading cocoa pod husks on their fields would spread disease, a worry echoed by official guidance from the Cocoa Research Institute of Ghana that discouraged using the husks as compost. The scientific literature says the opposite: composting the husks suppresses Phytophthora and reduces black pod incidence. Farmers ranked the bulkiness of organic fertiliser, the labour needed to apply it, and transport costs as their biggest obstacles, constraints that fall hardest on older farmers and on women and migrants with less secure access to family labour. The researchers also caution that biochar is not a universal fix, since it works best on acidic, infertile soils and can depress growth on neutral soils, meaning soil testing should precede any application.

The path forward, the authors argue, already exists in Ghana’s institutional landscape. Nearly 95 percent of surveyed farmers belonged to cooperatives, 93 percent received regular visits from extension agents, and a COCOBOD pruning initiative achieved adoption rates near 99 percent when machines were supplied through cooperatives. Embedding compost and biochar training in the same channels, alongside certification schemes such as Rainforest Alliance and Fairtrade and licensed buying companies, could replicate that success. With more than three quarters of farmers ready to buy amendments that nobody currently sells, the researchers see a clear opening for entrepreneurs to produce and distribute compost and biochar as a service, potentially supported by COCOBOD subsidies and the government’s One District One Factory policy. The raw material is free, the demand is proven, and the only thing missing, it turns out, is the message.

Subject of Research: Awareness and adoption of compost and biochar soil amendments among Ghanaian cocoa farmers

Article Title: Limited awareness prevents the use of compost and biochar as soil amendments by Ghanaian cocoa farmers

Article References: Awunyo-Vitor, D., Daymond, A., Quaye, A., Awudzi, G. K., Atuah, L., Mwafulirwa, L., Hammond, J., Turnbull, C., Lahive, F., Coole, S., Robinson, S., Hadley, P., & Sizmur, T. (2026). Limited awareness prevents the use of compost and biochar as soil amendments by Ghanaian cocoa farmers. Discover Agriculture, 4(1), Article 273. https://doi.org/10.1007/s44279-026-00754-6

Image Credits: AI Generated

DOI: 10.1007/s44279-026-00754-6

Keywords: cocoa farming, Ghana, compost, biochar, soil amendments, soil fertility, cocoa pod husks, smallholder farmers, agricultural extension, pyrolysis, sustainable agriculture, COCOBOD

Organic and sustainable farming operations increasingly depend on biological soil amendments of animal origin to build soil health, improve nutrient availability, and sustain crop productivity without relying on synthetic fertilizers. Poultry litter, a mixture of manure, bedding material, feathers, and feed residues, is one of the most abundant and widely used of these amendments. In Georgia, one of the nation’s leading poultry-producing states, approximately two million tons of poultry litter are generated annually, making it an economically and agronomically important resource for vegetable growers across the state. Sweet onions, a signature Georgia crop, are frequently grown in soils amended with these materials.

The research team, which included Harsimran Kaur Kapoor of the University of Georgia and Abhinav Mishra of the university’s Department of Food Science & Technology, set out to answer a deceptively simple question: how long does E. coli remain viable in field soils treated with different poultry litter-based amendments, and how do environmental conditions modulate that survival? The answer matters because pathogenic strains of E. coli and related foodborne pathogens can persist on produce surfaces and within soil ecosystems long after the amendment is applied, creating a window of potential contamination that growers must manage.

Across two growing seasons, the researchers observed a consistent pattern. Soils amended with heat-treated poultry pellets and soils amended with composted poultry litter both supported longer survival of E. coli than untreated control soils. Heat treatment and composting are both intended to reduce pathogen loads in manure-based products, yet the study indicates that the amended soil environment itself, even when the amendment has been processed, can create conditions more favorable to bacterial persistence than unamended soil. Nutrient availability, moisture retention, and organic matter content are among the factors that researchers generally associate with improved microbial survival in amended soils, and the study’s results align with that broader understanding.

The weather findings add a layer of complexity that the authors argue is essential for risk management. The influence of weather differed between the two growing seasons analyzed, pointing to the importance of year-to-year variability. Higher humidity was associated with greater bacterial survival, while stronger winds generally reduced survival. Rain and warmer soil temperatures could promote bacterial persistence, whereas higher air temperature and wind speeds tended to reduce it. Taken together, the results suggest that extreme weather events, rather than average seasonal conditions alone, may play an important role in determining how long bacteria can survive in agricultural soils.

This distinction between averages and extremes carries real consequences for how food safety risk is modeled and managed. A season with a modest average temperature but several intense rainfall events may pose a different contamination profile than a season with a higher average temperature and steady winds. Risk-based approaches that rely solely on seasonal or monthly climate summaries could therefore underestimate the survival window of pathogens following specific extreme events. The authors note that understanding how amendment practices interact with extreme weather may help inform risk-based management approaches under real field conditions, where growers cannot control the weather but can adjust amendment type, timing, and application practices.

The crop at the center of the study is not an arbitrary choice. Onions have been linked to several major foodborne illness outbreaks in North America in recent years. In 2024, the U.S. Food and Drug Administration investigated an outbreak of E. coli O157:H7 associated with slivered onions served on McDonald’s Quarter Pounder burgers. Earlier incidents include a 2020 outbreak of Salmonella Newport linked to red onions across the United States and Canada, and a 2021 outbreak of Salmonella Oranienburg tied to whole fresh onions imported from Mexico. These outbreaks resulted in thousands of reported illnesses and hundreds of hospitalizations, underscoring that allium crops, long considered lower risk than leafy greens, can serve as vectors for serious foodborne disease.

Sweet onions present particular production considerations. They are typically grown in sandy soils with careful irrigation management, harvested after months in direct contact with the soil environment, and often consumed raw or with minimal processing, which means no kill step intervenes between field and consumer. Any pathogen that persists in the soil or on the bulb surface at harvest therefore represents a direct route into the food supply. Understanding whether and how poultry litter amendments extend the survival window of E. coli in these soils gives growers and regulators a concrete variable to work with when designing pre-harvest intervals, amendment application schedules, and water and soil testing regimes.

The regulatory context is also evolving. The authors note that regulators continue to seek data on the food safety implications of biological soil amendments of animal origin, a category that includes raw and processed manures, composts, and pelleted products. Field-scale studies like this one provide the kind of empirical evidence needed to calibrate standards that are both protective of public health and workable for growers who depend on these amendments for soil fertility. The interaction between amendment type and local environmental conditions that the study documents suggests that a one-size-fits-all national standard may be less effective than frameworks that account for regional climate, weather variability, and dominant amendment practices.

For Georgia’s sweet onion industry, and for produce growers in poultry-heavy regions more broadly, the study offers a practical takeaway: the combination of amendment choice and weather exposure deserves active attention in food safety planning. Growers who apply heat-treated poultry pellets or composted poultry litter may want to consider how upcoming rainfall, humidity, and wind patterns could extend or shorten pathogen survival in their fields. As extreme weather events become more frequent and more intense, the researchers’ central finding, that it is the extremes rather than the averages that shape bacterial persistence, is likely to grow in importance for anyone working at the intersection of soil health, agricultural productivity, and the safety of the fresh produce that reaches consumers’ tables.

Subject of Research: Survival of E. coli in poultry litter-amended soils under varying weather conditions in sweet onion production

Article Title: Study finds poultry litter-based soil amendments and weather influence E. coli survival in Georgia sweet onion production systems

Article References: Study finds poultry litter-based soil amendments and weather influence E. coli survival in Georgia sweet onion production systems. (n.d.). Original publication

Image Credits: AI Generated

DOI: Not provided

Keywords: E. coli, poultry litter, soil amendments, sweet onions, food safety, extreme weather, Georgia agriculture, Risk Analysis, compost, foodborne illness, pathogen survival, produce safety

The research, published in the journal Nitrogen Cycling, was carried out by a team led by Zonghai Chen and corresponding author Bo Li of South China Agricultural University, together with colleagues including Yige Liu, Jiashuai Hu, Ying Lu, and Lars Elsgaard. The investigators set up an intensive vegetable field planted with lettuce varieties, a cropping system typical of the humid subtropical conditions that dominate much of Southern China’s vegetable belt. Five biochar application rates were compared, spanning from zero as a control up to 40 metric tons per hectare, all under conventional nitrogen fertilization. The biochar itself was produced from rice straw, an abundant agricultural residue, through pyrolysis at 500 degrees Celsius, a thermal conversion process that locks carbon and mineral nutrients into a porous, charcoal-like material prized for its ability to alter soil physical and chemical properties.

The results were striking. Over the two-year experiment, the 20-ton-per-hectare treatment increased vegetable yields by 10 to 29 percent compared with plots that received no biochar. Nitrogen use efficiency, the proportion of applied fertilizer nitrogen actually captured by the crop, improved by 18 to 160 percent, a range that reflects year-to-year variability but consistently favors the moderate dose. Plant nitrogen uptake rose by 14 to 33 percent, meaning the lettuce not only grew larger but also accumulated more of the nutrient that drives leafy growth. In a sector where nitrogen use efficiency often languishes well below 40 percent, gains of this magnitude represent a meaningful step toward both economic and environmental sustainability, reducing the fertilizer inputs farmers must purchase while cutting the nutrient losses that degrade rivers and groundwater across the region.

What happens underground proved just as important as what happens above it. Biochar transformed the physical architecture of the soil, promoting the formation and stability of water-resistant aggregates—the small, crumb-like structures that give healthy soils their spongy texture, allowing them to hold moisture during dry spells yet drain freely after heavy rains. This aggregate stability matters enormously in Guangdong’s climate, where intense monsoonal downpours can sluice nutrients out of poorly structured soils. The amendment also increased microbial biomass, swelling the populations of bacteria and fungi that mediate decomposition, nutrient mineralization, and nitrogen transformations. At the optimal rate, the researchers’ composite soil quality index climbed 39.7 percent above the control in the first year and 50.6 percent higher in the second year, indicating that the benefits were not a fleeting first-season flush but a persistent improvement that actually strengthened with time.

To understand how these soil changes translated into better crops, the team employed statistical modeling that traced the pathways linking biochar to plant performance. Their analysis indicated that biochar influenced vegetable production and nitrogen utilization largely through three interlocking channels: altered soil nutrient availability, shifts in microbial communities, and improved soil structure. Higher soil quality scores were positively associated with vegetable yield, nitrogen uptake, and nitrogen use efficiency, suggesting a coherent causal chain in which the amendment acts first on the soil environment and only subsequently on the plant. This mechanistic clarity is valuable because it distinguishes biochar from a simple fertilizer substitute. Rather than directly feeding the crop, the material appears to function as a soil ecosystem engineer, creating conditions under which native nutrient cycles and microbial processes operate more effectively in partnership with conventional fertilization.

Perhaps the most consequential finding, however, is what did not happen at high application rates. The response of vegetable yield and nitrogen-related indicators was decidedly non-linear, rising steadily as biochar application climbed toward roughly 20 tons per hectare and then declining beyond that threshold. Plots amended with 30 or 40 tons per hectare showed no additional yield benefit, and the researchers caution that excessive rates could disturb nutrient balance or disrupt microbial conditions. In other acidic or nutrient-poor soils, very high biochar doses can immobilize nitrogen, raise pH beyond optimal ranges for some crops, or dilute mineral nutrient concentrations in ways that undermine rather than enhance fertility. The message for practitioners is unambiguous: more biochar is not necessarily better, and the amendment behaves as a dose-responsive tool rather than a cure-all to be applied liberally.

The dose-response relationship also carries significant economic weight. Biochar is not free; producing, transporting, and incorporating tens of tons of material per hectare represents a substantial investment, particularly for smallholder vegetable growers operating on thin margins. When the research team weighed crop benefits against biochar costs under the conditions of their experiment, 20 tons per hectare emerged as the most favorable amendment rate, delivering the strongest combination of yield gains, nitrogen savings, and soil improvement per unit of material applied. This kind of cost-benefit framing is essential if biochar is to move from research plots into the fields of working farms. An intervention that performs brilliantly in a scientific trial but fails an economic test will remain a curiosity; one that pays for itself through higher yields and reduced fertilizer waste has a realistic path to adoption.

Bo Li, the corresponding author, emphasized this balanced perspective in discussing the findings. According to the study team, a moderate application rate provided the best balance between improving soil conditions, supporting soil microorganisms, and helping vegetable crops use nitrogen more efficiently. That framing captures a broader shift in soil science away from viewing amendments as single-purpose inputs and toward managing them as components of an integrated system. In the Guangdong experiment, biochar did not replace nitrogen fertilizer; it made conventional fertilization more effective by reshaping the soil matrix in which nutrient transformations occur. For policymakers and extension services promoting low-carbon agriculture, this synergy matters, because biochar also sequesters carbon in a stable form, meaning a practice that boosts farm profitability may simultaneously contribute to climate mitigation.

The authors are careful to note the limits of their evidence. The experiment spanned only two years, a short window in the life of a soil system, and longer-term studies will be needed to determine how long the observed benefits persist and whether repeated moderate applications are required in warm, high-rainfall regions where biochar may decompose faster and nutrients cycle rapidly. Tropical and subtropical conditions can accelerate the aging of biochar particles, potentially altering their effects on nutrient retention over time. Questions also remain about how the optimal rate might shift across different soil types, crops, and management regimes beyond the lettuce rotations studied here. Still, the consistency of the improvements across two growing seasons, the strong mechanistic support linking soil quality to crop performance, and the clear identification of a cost-effective optimum give the findings practical credibility.

Taken together, the study positions carefully optimized biochar application as a realistic route toward more productive, nitrogen-efficient intensive vegetable farming in Southern China and potentially in comparable systems worldwide. By pinpointing 20 tons per hectare as the sweet spot, the research converts a broad enthusiasm for soil amendments into an actionable prescription, one that acknowledges the economics of farming and the complexity of soil ecology in equal measure. As demands on intensive vegetable systems continue to grow alongside the region’s population, strategies that squeeze more food from every kilogram of applied nitrogen—while restoring the structural and biological foundations of the soil itself—will only become more valuable. This experiment suggests that, with the right dose, rice straw that once might have been burned or discarded can become a cornerstone of that effort.

Subject of Research: Effects of rice-straw biochar application rates on vegetable yields, nitrogen use efficiency, and soil quality in intensive vegetable fields in Southern China

Article Title: Right dose of biochar boosts vegetable yields and nitrogen efficiency in Southern China

Article References: Right dose of biochar boosts vegetable yields and nitrogen efficiency in Southern China. (n.d.). Original publication

Image Credits: AI Generated

DOI: Not provided

Keywords: biochar, nitrogen use efficiency, vegetable production, soil quality, soil aggregates, microbial biomass, rice straw pyrolysis, intensive farming, Guangdong Province, soil amendments, nutrient availability, sustainable agriculture