Studies on postharvest losses in Ethiopia for different grains have been made in the past. Experts advised that it is not possible to generalize about postharvest losses for all crops for a variety of reasons. However, the “average” total postharvest losses (PHLs) ranged between 15 to 27 percent. In all cases, storage losses are very high, and the ranges in loss estimates are wide. Such variations could be due to the methodologies used in loss assessment envisaged and due to the differences in study locations. As a result, reliable data pertaining to PHLs are still lacking, especially along supply chains of the different commodities. Most studies have identified the causes of PHLs to be the lack of appropriate and affordable technologies for the different operations, poor infrastructure, lack of awareness, lack of financial support for postharvest operations, tendency of the extension system to focus on pre-harvest operations rather than postharvest, etc.
Numerous options for reduction of postharvest losses in grain crops have been developed and recommended. Ali and Abraham revealed that these methods included cultural practices such as prompt harvesting, proper drying before storage, use of resistant crop varieties, admixing grain with teff, finger millet, or inert dusts, use of airtight storage containers, treatment of grain with pesticides, and use of combination of different compatible options in an integrated manner using integrated pest management (IPM)). However, more efforts are needed to utilize the existing technologies and to develop new, affordable, and more effective technologies to mitigate PHLs of the selected commodities based on a value chain approach.
Grain crops (cereals and pulses) are the major food crops for the majority of the Ethiopian people. They are also sources of income at household level and contribute to the country’s foreign exchange savings. Within the category of grain crops, cereals are the major food crops, both in terms of the area they cover and volume of production. They are produced in larger volumes compared with other crops because they are the principal staple crops. It is indicated that five major cereals such as teff, wheat, maize, sorghum, and barley are the core of agriculture and food in Ethiopia, accounting for about three-fourths of the total area cultivated, about a third of agricultural gross domestic product (GDP) and two-thirds of calories consumed.
It is reported that, according to a 2017 Central Statistical Agency (CSA) report, 12.7 million hectares of land were covered by grain crops and about 290.4 million quintals of grains were produced in private peasant holdings in 2016/17. It is indicated that there has been substantial growth in cereals, in terms of area cultivated, yields, and production, but yields are low by international standards, and overall production is highly susceptible to weather shocks, particularly droughts. Much of the increase in production in the past decade has been due to increases in area cultivated. However, “little” suitable uncultivated land remains in the highlands, apart from pasture land. According to Hamza et al, soil degradation from erosion and soil compaction also threatens crop yields.
Uncertain rainfall and very low levels of irrigation make intensive cultivation with improved seeds and fertilizer risky. Hence, increasing production and productivity is faced with serious challenges in improving food security through ensuring adequate food availability and increasing household incomes. The attempt to ensure food security was made merely by increasing crop productivity and production in the field. However, increasing food production is being “constrained” by limited land and water resources and increased weather variability due to climate change. Regarding productivity per unit area, Ethiopia is far below average, even by some African standards. On the other hand, a huge amount of losses occurs at different stages “after” crops are harvested and before consumption, after a large investment of time, labor, and money in the production process.
Postharvest losses are estimated to be as high 37 percent in sub-Saharan Africa. Recent report indicated that more than one-third of food is lost every year in the postharvest operations. In Ethiopia, crop losses occur in cereals during cutting, drying, threshing, winnowing, and transportation, respectively. Postharvest losses of all crops in the country have been estimated to be very high, reaching nearly half of the harvest. However, these losses occurring in the postharvest process have “not” been given the attention they deserve and have even been neglected for a long time. Many experts realize that appropriate postharvest management (PHM) is the missing link between production and consumption, contributing significantly to the food insecurity problem.
Postharvest losses cause losses of economic value of food produced, waste of scarce resources such as land, labor, water, and capital. FAO reveals losses of non-renewable resources such as fertilizer and energy, all of which are used to produce, process, handle, and transport food. Solutions to reduce postharvest losses require relatively modest investment and can result in high returns compared to increasing the crop production to meet the food demand. It is suggested that with continued efforts to increase production and productivity, it is recognized that PHL reduction can provide an environmentally sustainable and cost-effective contribution to food security. It also improves income of farmers, compared to a “sole” reliance on increasing production with limited natural resources, and in an era of high and volatile food prices.
To reduce postharvest losses, it is first necessary to know the scale of these losses across the different stages of production. It is crucial to know which steps are critical for losses and to identify the causes that can be controlled and improved in the whole process. However, efforts to identify and resolve the critical issues along the value chain in many sub-Saharan African countries, including Ethiopia, are impeded by the lack of a simple, adoptable, and well-defined practical methodology. This helps to estimate the losses in quantitative and qualitative terms. The effort of assessing PHL requires a guideline on the precise, time-saving, effective, and lowest-cost way of estimating grain losses. The estimate could be used in planning, designing, and targeting of loss reduction interventions.
Studies have been conducted on the methodology of assessing losses and designing loss reduction strategies that can be used in Ethiopia. They also lead to the formulation of a nationally harmonized and validated systematic guideline. One of the major objectives of this study is to review and document available in-country information on losses in the grain crops post-production system and identify best technologies and practices recommended locally. The other objective is to tailor workable loss assessment methodologies that would provide standardized and reproducible results. It helps to generate information for sound decision-making and implementation of effective loss reduction measures. These measures are important instruments of preventing food insecurity.
The main stages within the agricultural supply chain during which losses occur in grain crops and the associated causes of losses may be distinguished as indicated next. These stages are harvesting, drying, threshing and shelling, winnowing, transport to farm, farm storage, and transport to market and market storage as briefly mentioned earlier. Harvesting is determined by the degree of maturity. It affects successive operations, particularly threshing, winnowing, storage, processing, and preservation. The optimum time of harvest for grain crops is when the grain reaches physiological maturity at suitable moisture content (WB). However, Ethiopian farmers “commonly” harvest most crops after physiological maturity is attained and when the moisture content reaches low level.
Low moisture content helps to dry the crop in the field and gives farmers adequate time during the overlapping operations in the peak activity time that compete for labor. It is obvious that harvesting too early or too late has its own consequences. While late harvesting results in extended pre-harvest field drying, which may ensure good preservation, it also heightens the risk of loss due to different reasons. The longer the harvest remains standing in the field, the greater the risk of loss due to shattering before harvest; physical grain loss occurs due to incomplete harvesting of straws which consists of lodging loss and standing straw loss; rain will encourage the spread of molds; animals mainly birds, rodents, and monkeys will take their share, while insects will lay eggs in the grain that will continue to do damage during storage.
Poor farmers, however, harvest crops too early due to food deficiency or desperate need for cash. In such instances, the food incurs a loss in nutritional and economic value and may get wasted if it is not suitable for consumption. Farmers determine the right time of harvesting based on their long-established practices that are based on the crop calendar, color change of leaves, harvestable parts, and texture of the seed or kernels. They attempt to reduce loss at harvest by harvesting before the crop is too dry to shatter before or during harvesting. This is particularly important in the case of wheat and haricot bean, which are highly susceptible to shattering loss.
It is important to have reliable and consolidated information on the extent and causes of postharvest losses for effective planning and implementation of loss reduction interventions. It is reported that there is inadequate postharvest research conducted in Ethiopia. Most of these studies are limited as they are focused on storage-related losses in selected parts of Ethiopia. Few recent studies follow the concept of a supply chain-based approach. The methods used for storage studies are designed experiments. However, most postharvest loss assessments strongly rely on rapid appraisal techniques through focus group discussions and key informant interviews, often collecting information based on the perceptions of farmers.
The range of postharvest losses reported by various experts for different crops is wide. As mentioned earlier, the average postharvest loss reported in different reports is high. Also, estimates are too divergent and inconsistent to guide policy, programs and projects in the country. Such variations in estimates are attributed to, among other causes, lack of a standard loss assessment methodology. The causes of postharvest losses reported in Ethiopia include limited awareness, limited availability of and access to postharvest technologies, and limited attention given to postharvest research and extension and infrastructure. The responsible government agency should support farmers in controlling postharvest losses and guaranteeing food security in the country based on PHL studies.
BY GETACHEW MINAS
THE ETHIOPIAN HERALD JUNE 3/2021
