Causes of post-harvest losses are the events that lead to the degradation of grains in quality and quantity. For example; aflatoxins cause discoloration of grains. Post-harvest losses do not occur by themselves or as they say; do not occur in a vacuum. Some various events or practices make post-harvest losses occur. Post-harvest losses occur at each point of the value chain. That is; during pre-drying, harvesting, threshing, transportation, storage, and processing. Read on to find out more about the causes of post-harvest losses in grains.

The events that occur at each stage of the value chain can be grouped into two; internal and external factors. Internal factors refer to stages that the farmer may have control over. While external factors refer to factors totally beyond the control of the farmer.

Internal Causes of post-harvest losses

The internal causes include many of the stages along the value chain. Let’s look at three of these stages.

• Harvesting Practices: harvesting stage is largely determined by crop maturity and weather conditions. At the harvesting stage, several things can go wrong. Things such as wrong or rough handling of the crop while harvesting, lack of appropriate harvesting tools, equipment, and containers, and untimely harvesting.
• Transportation Practices: lack of appropriate transport systems and lack of appropriate transport vehicles. This challenge is however more prevalent in developing countries.
• Storage Practices: this includes the inadequate use of appropriate storage bags and containers for storing crops, inappropriate care of warehouses, inadequate storage facilities, and improper management of pests and insects such as weevils for grains.

External factors of post-harvest loss

External factors are events that are totally beyond the control of the farmer or commodity trader. These include;

• Weather conditions: rainfall, whether excessive or not, and sunshine whether hot or not, affects the quality of crops. Excessive rainfall may cause flooding of farmlands and warehouses and destroy farm or stored crops. It may also disrupt preharvest and postharvest drying processes. Excessive sunshine will cause an increase in temperature and decrease the storage life of a crop as most factors that destroy crops, such as mold growth occur at a faster rate when temperatures are high.
• Time: the longer the produce, crop, or grains are kept in storage, the greater the decline in the quality of the product especially for those that have a short storage life. Change in taste preferences or lack of immediate market for produce can increase the storage time of production and this may cause post-harvest loss due to insect infestations.
• Socioeconomic factors: social trends such as rural-urban migration have caused urban areas to increase drastically, resulting in increased demand for food produced in urban areas. Hence, to cater to the increasing demand for food products, especially grains, we are forced to import from other countries to subsidize what we have. Grain importation can introduce a new species of insects that pose a very significant problem. In 1980, along with grain importation, new insect species were introduced to Africa which caused weight losses of up to 30% in just 3-6 months of storage (Boxall 2001).

In Conclusion

Post-harvest losses do not occur in a vacuum. Knowing the events and practices that encourage post-harvest losses will help to know what we can do to control, manage and reduce the challenge. Farmers and commodity traders must do everything in their power to put in place and practice the appropriate measures and practices to reduce post-harvest losses.

At Sesi Technologies, we are dedicated to helping grain farmers, traders and aggregators reduce post-harvest losses and increase revenue through affordable technology. Kindly get in touch on 0555699870 and let us help you. You can also download our GrainMate Grain Moisture Meter here to have access to our wide range of post-harvest management resources.