Traditional methods of storing grains

Food grains are the most commonly stored durable food commodities in the tropic and subtropics usually stored to provide food and feed reserves as well as seed for planting. The major grain crops cultivated in tropical and subtropical nations are maize, rice, wheat, sorghum, cowpeas, soybean, pigeon pea, kidney beans.

Traditional storage techniques are usually cheap, eco-friendly and impart high shelf life to the stored commodities. A substantial amount of food grains is being damaged after harvest due to lack of adequate storage and processing facilities. The Food and Agricultural Organisation (FAO) estimates that the world loses about 10 percent of all stored grain globally. In Sub-Saharan Africa, 25 to 40 percent of food grain losses occur during storage at the farm level.

According to Julia Kamau, the head of programme Seed Savers Network, storage practices differ and there are small or big storehouses, indoor or outdoor, temporary or permanent and individual or community storage design.

Solarisation
The process of heating grain in the sun to kill insects is one of the oldest practices by farmers before storing the grains. The seeds are usually spread on the bare grounds, polythene or on tarpaulin, bamboo mat, roadsides or on rooftops to reduce the moisture content and kill pests.

 “The solarisation time varies based on the products. The dried grains are chewed to determine whether the grains are dried to a satisfactory level. If the grain is placed in an insect-proof container, then it will remain free of infestation,” she says.

Open fireplace
Smallholder farmers usually store food grain crops above the kitchen fire in the farm hut or in open where the high temperature due to direct solar radiation may also kill the developing larvae in the seeds.

Aerial storage
Unshelled maize cobs and other unthreshed cereals are suspended in bunches or sheaves, using rope or plant material, under eaves, from the branches of trees or the top poles driven into the ground. 

Julius Ayebare a subsistence farmer says, “The grain dries in the air and the sun until it is needed by the farmer for consumption or marketing. When the grains are stored in the open air, the farmers always ensure to protect the grains from rainfall by covering them with polyethene. The disadvantage of open-air storage is that the grain is exposed to the environment and pests.”

Storage bags
Short duration storage of food grains in sacks is widely used in farms, villages and commercial storage centers. Sacks are made of woven jute, sisal, local grass, cotton and depend on the materials that are available in the area.
“Ranging from 25 to 100 kilogramme sizes, polyethylene storage bags create a highly efficient, hermetic storage environment for all crops. 

Polyethylene bags are placed inside ordinary storage bags for an additional layer of protection to form multi-layer polyethylene storage bags to ensure water resistant and completely air tight storage condition,” Kamau says.
Bags can be transported and handled without special equipment; above all these sacks allow for gaseous exchange and insect control using fumigants in a closed storehouse or underneath a plastic sheet covering the sack is made possible.

Gourds
In many rural areas, gourds are used for storing small quantities of food grains required for home consumption or planting for a period between six months and one year.
According to Isaac Bukenya, a subsistence farmer in Masaka, gourds and calabashes are normally kept indoors or under shelter and above the kitchen or places where they are not prone to insect infestation.

“Gourds used for grain storage are treated with varnish, paint or linseed oil and once the grains are poured in, the lid is covered with mud or cow dung to make an airtight storage condition,” he says.  

Platform storage
The traditional raised platform is used for stored grains to reduce moisture, larvae killing, and to discourage insects or other pests. In some instances, straw mats, bamboo mats or raffia mats are spread on the platform. The legs of the raised platform are shielded with rodent proof. The high temperature due to direct solar radiation continually heats up the grains which reduce the moisture content and may also kill the developing larvae in the seeds thus preventing insect infestation. 

Underground pit
Underground grain storage is carried out by farmers in an agro-ecological zone with low water table for long duration storage of large quantities of threshed grains such as cow peas, millet, and sorghum ranging
Storage pits may be of two different types; the bell-shaped ones with a pronounced storage chamber and a small entrance and cylindrical ones with a wide opening and walls supported with mats. Because of the pit depth it keeps the grain cool and storage duration could be between one and five years. However, this type of storage causes increased moisture content of the grain with time, leads to mould damage, lower grain quality and reduction of viability.

Storage with cow dung
In some parts of East Africa, seeds meant for next season sowing are stored with cow dung. The seeds are first dried thoroughly.

Farmers then collect fresh cow dung and make it to a plate-like round shape and the seeds are embedded into the cow dung and then sun dried for 2–3 days depending on the intensity of the sunlight. Kamau says, “In the process of sun drying, the seeds get stuck onto the cow dung and then stored in an open or inside a wooden box. Seeds treated this way can be stored for up to a year. Rural farmers believe that cow dung possess properties that protect such seeds from pests.”

Others first dry the dung, burn it to form ash and then mix with the dry seeds. Other farmers mix dried seeds with ash, salt, dust from baked bricks and Tithonian leaves before storage.