Introduction: The Scale of Global Food Loss and Waste
Every year, a significant proportion of food produced for human consumption is lost or wasted. Approximately 14% of the world's food, valued at $400 billion, is lost annually between the stage of harvest and the retail market (FAO 2019). At the same time, an estimated 17% of food is wasted at the retail and consumer levels (UNEP, 2021). In light of rising food prices, widespread food insecurity, and growing pressure on natural resources, avoidable food loss and waste are not acceptable. The world’s natural resources – such as soil, water, fossil fuels, and nutrients – are limited and must be used more efficiently and responsibly.
Potato Losses: An Economic Perspective
The financial assessment of potato damage and loss along the value chain exposes the economic impact of this low performance in potato production. A study by GIZ in Kenya shows in each harvest season, 2,715 kg or 19% of per-hectare production is damaged or lost, representing a loss of KES 42,824 (EUR 363) per hectare. Extrapolating these per-hectare losses to the national production level, we can assume that 815,000 tonnes of produce are damaged or lost each year, representing a value of around KES 12.9 billion (EUR 109 million).
Defining Food Loss and Waste
According to FAO, food loss refers to a decrease in edible food mass throughout the part of the supply chain that provides explicitly edible food for human consumption. Therefore, food destined for human consumption that falls out of the human food chain is considered food loss or waste. This approach distinguishes between 'planned' non-food uses and 'unplanned' non-food uses, with the latter being counted as loss. Food loss occurring at the end of the food chain (retail and final consumption) is called 'food waste' and results from retailer and consumer behavior.
Potato Farming in Kenya: An Overview
Potatoes are grown by up to 1,200,000 farmers, who are mainly smallholders. It is estimated that 83% of the land under potato cultivation belongs to smallholders dedicating 0.2 to 0.4 hectares to potato production, while approximately 17% of potato plots belong to larger-scale farmers dedicating 2 to 10 hectares to the crop (Janssens et al., 2013). The average production in Kenya is estimated to be 7 to 10 tonnes per hectare (Muthoni et al., 2011), compared to a global average yield of 17 tonnes per hectare (FAOSTAT 2011). Kenyan farmers achieve up to two harvests per year. The total production area has increased in recent years and is estimated to have reached 150,000 to 160,000 hectares to date. Most farmers produce two potato crops a year because of the bimodal rainfall in most potato-growing areas. The long rainy season lasts from March/April to June/ July, while the short lasts from October to December.
Challenges in Potato Farming
Limited pest management and low soil fertility mean current production practices are not sustainable. This situation is further aggravated by the remnants left in the field after harvest that produce so-called volunteer plants in the next season. Even though crops are rotated, the volunteer plants will carry diseases from one season into the next. Most of the farmers leave these volunteer plants in the field, using them mostly for home consumption. The average quantities remaining in the field are estimated, and at least 5% of the potato crop is left on the ground. A total of 50% of farmers allow the volunteer plants to grow for home use, while others uproot the remnants. A recent survey showed that bacterial wilt was the most prevalent disease, affecting 77% of potato farms, followed by late blight, affecting 67%, and viral diseases, affecting 12% (Kaguongo et al., 2014).
Post-Harvest Losses in Potatoes - Storage and Market Challenges
The majority of farmers do not harvest potatoes when it is raining. However, those who do harvest during the rains experience damage and loss of up to 1,469 kg/ha, mostly caused by the potatoes rotting. These losses stand at 344 kg/ha, as indicated by the National Potato Council of Kenya. Farmers tend to harvest during the rains to reach the market early and fetch higher prices. Also, traders force farmers to harvest early.
Most farmers sort and grade potatoes at harvest. The majority of farmers (60%) grade by size, with 85% of their crop being either medium—or large-size potatoes. Sorting and grading mainly involve separating out small potatoes for seed. After deducting potatoes for home use, medium and large tubers, along with cut, bruised, and green tubers, are bagged for sale.
As there are usually only a few months between harvests, storing potatoes in large storage facilities is not a common practice in Kenya. However, smaller quantities may be stored on farms. Those operating modern storage facilities are the larger processors or producers of seed potatoes. Most farmers (90%) stored some potatoes after harvest, but most farmers (60%) stored potatoes for seed.
The fork jembe is the main harvesting tool for farmers, although most (90 %) consider it damaging (cuts and bruises) potatoes during harvest. The damage caused by using fork Jembes was estimated at 679 kg/ha. That said, other tools, such as the hoe or stick, damage crops even more.
Most farmers (90%) use casual labor to harvest potatoes, and only 10% also employ family members in their workforce. An important reason for this relates to how work is remunerated: work provided by family members is usually not paid for, making them less willing to work on the family farm. Most farmers (80%) consider harvesting operations the main cause of potato damage during harvest. The amount of damage caused by this type of labor can be estimated at 488.2 kg/ha. However, farmers experience most of their losses during production, e.g., through disease and other issues.
Only a few farmers store potatoes to wait for better market prices; off-season production produced under irrigation secures high prices, so seed tubers are mainly stored in diffused light stores (DLS), which are shaded and aerated. This type of store provides excellent conditions for seed tubers but is not widely used. Farmers sell directly after harvest. Most farmers experience losses during potato storage, mainly caused by rotten potatoes affected by disease or damage.
Brokers act as intermediaries between farmers and local traders and keep in close contact with farmers to stay abreast of their available quantities and varieties. Brokers work in groups, and each group can deal with 30 to 70 farmers. Brokers get a fixed fee per bag from local traders. Brokers tend always to be male as the work involves heavy lifting. Contrary to the perception that they only exploit farmers, brokers also work under difficult conditions. They reported that lifting heavy bags damages their health and that some have been injured when loading and offloading extended bags. It was observed that many of them appeared in poor health.
One of the challenges brokers face is the failure to implement standards in potato marketing. As intermediaries between farmers and traders, they must convince farmers to accept extended bags for sale. Implementing standard bags would facilitate their business operations. When brokers pack, they try to avoid including bad-quality potatoes in the bags; however, they do not grade or buy potatoes by grade.
Solutions for Reducing Potato Losses
To address potato losses, strategies include improving pest management, adopting sustainable farming practices, using better harvesting tools, and investing in storage solutions. Standardization in potato marketing and education for both farmers and brokers can also significantly reduce losses and improve the overall value chain efficiency.
