Contributed by William Nkhunga.
The Bible verse “a time to plant and a time to uproot” (Ecclesiastes 3:2) is one of the best ways to explain this time of year at Kusamala. On 23 April 2014, the largest permaculture demonstration centre in Malawi embarked on harvesting groundnuts, or peanuts (Arachis hypogaea), which were planted in the middle portion of the staple field. At Kusamala, peanuts are part of the crop rotation as they are a nitrogen fixing legume. They fix atmospheric nitrogen and have the advantage of generating residual nitrogen in the soil that benefits subsequent crops, especially when peanut residues are incorporated into the soil during ploughing.
The peanuts were planted with the first soaking rains on 17 December 2013 and it has taken 121 days for the nuts to fully mature. After planting, many other activities took place including weeding, banding, and pest and disease scouting. As harvesting time was approaching, the peanuts maturity had to be determined by inspecting plants in different parts of the rows in the field every couple of days. Normally, fully matured peanuts start to loose their green color, the leaves turn yellow, the vein colour inside the mature pods turns dark, and the peanut skins will be papery thin and light pink.
After peanuts are harvested it is important to control the moisture content during the drying process, as a high moisture content makes them prone to mould infestation, specifically the development of Aspergillus flavus fungus and the dangerous aflatoxins the fungus produces. To minimize aflatoxin and disease, it is important to dry peanuts effectively. We used the Mandela cock (stack) system instead of traditional drying techniques such as laying pods in the field for several days, drying ground nuts on roofs, heaping groundnuts in the field or in houses, or storing wet groundnuts in bags while waiting for the sun, because those traditional techniques greatly increase the risk of aflatoxin development.
To create a Mandela cock drying system, first build a circular platform of soil about 1-2 meters across and 18 inches high. Place the peanut plants in a circle around the perimeter of the platform, with the pods in the inner part of the circle. Continue to place the plants around the circle, building up the layers and gradually reducing the diameter of the circle until there is only a small opening at the top of the cock. Then cover this opening with peanut plants with the pods turned downwards. The cock can be built to a height of one to one and half meters and it takes 2-4 weeks of drying to reach the recommended moisture content of 6-8%.