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Postharvest losses: Curse to African farming

Adopting cost-effective technologies could help smallholders in Sub-Saharan Africa tackle postharvest losses and increase their income, a report says.

According to the FAO, postharvest losses reduce the income of the continent’s farmers and value chain actors that depend on farmers by about 15 percent.
The report by the International Food Policy Research Institute (IFPRI) released last month (March) highlights the scale of postharvest losses and the gains farmers could make by using novel technologies such as Purdue Improved Cowpea Storage (PICS) bags, metal silos and zero energy cool chamber (ZECC).

Siddharta Baral, a co-author of the report and senior research assistant at the US-based IFPRI, tells SciDev.Net smallholders to lack access to credit and savings, thus making it difficult for them to adopt practices and cost-effective technologies that can minimize such losses.

“Women and children tend to suffer disproportionately from food insecurity, and post-harvest [losses] contribute to food insecurity,” he adds.

Baral says that the report resulted from a review of journal articles and policy reports on postharvest losses from credible organizations such as the FAO.

According to Baral, their research found postharvest losses that affect mangoes to be 20-50 percent in Ghana and 39-52 percent in Kenya.

Baral says the study assessed the cost-effectiveness of technologies available for preserving grains from harvest to consumption and found the three technologies — PICS, metal silos, and ZECC — better compared to other methods for storing grains such as packaging products in non-ventilated sacks.

“Typical postharvest losses for cabbages in Ghana are extremely high (60 percent)… Use of the ZECC reduced the weight loss to 36 percent,” the report says, noting that a trial in Kenya shows that metal silos helped reduce losses caused by insect pests, thus helping smallholders save 150–198 kilograms of grain, which cost US$130.

According to Baral, poor harvesting practices, pest infestation on the field, and lack of transportation could lead to substantial losses.

Hari Kishan Sudini, principal scientist, ICRISAT, India, says the PICS bags are “totally chemical-free technology and the bags are re-usable so long as they are intact”.

Many studies on PICS, he notes, indicate that farmers could use them for at least three seasons (three years).

Robert Owusu, a postharvest loss specialist at the Ghana-based Savanna Agricultural Research Institute, tells SciDev.Net that PICS could also help prevent postharvest losses of other crops.

“Although the PICS bag was designed for the storage of cowpeas, studies in northern Ghana have shown that it could be used for storing well-dried cereal grains,” he says.
But Owusu adds that if cereal grains are not dried well and stored in PICs bags there is the likelihood of aflatoxin growth as a result of moisture accumulation.