ZIMBABWE boasts several indigenous peanut strains that have been grown in the country since the late Iron Age.
It was during this sedentary period in pre-history that the terrigenous Zimbabweans ceased to be nomadic and settled on vast tracts of land, where they began to develop most of the crops we consider indigenous to our land and dietary blue-print today.
Peanuts (amazambani or nzungu), in the local Shona and isiNdebele languages, is one such crop.
The peanut or groundnut (arachis hypogea L.) is a member of the legume family.
It is said to originate from South America (Bolivia and adjoining countries) as well as in tropical and sub-tropical Central Africa, Southern Africa, Zimbabwe, Malawi, Mozambique, Madagascar, Tanzania, South Africa and Zambia where several indigenous African varieties of peanuts exist.
In colonial times, the Portuguese took a variety of nuts from Brazil to West Africa, while the Spaniards introduced a different strain of peanuts to the Philippines from where they spread throughout tropical and sub-tropical Asia.
In countries such as Malaysia, Indonesia, Nusa Tenggara, (the lesser Sunda Islands) and India, the peanut is used in many culinary dishes, liqueurs, confectionary, breakfast cereal mixes and general quisine.
The same can be said in Zimbabwe where the indigenous) Shona peanut butter (dovi) accompanies many local dishes from sweet morning peanut butter porridge (bota ne dovi) to (nhopi) pumpkin in peanut-butter sauce to savoury vegetables (muboora ne dovi), squash leaf vegetable and peanut butter or (tsunga nedovi) mustard leaf vegetable and peanut butter or (mutakura) mealie samp kernels and peanuts – a traditional Shona meal with a high starch content and peanut, vegetable protein.
This dish, mutakura, was specially prepared for men and women who had to undertake arduous agricultural tasks in the fields, particularly in the Zimbabwean dry winter months of May, June, July and August where nomadic traditional hunters and farmers were active.
In countries with less beef supplies and, indeed, the northern hemisphere, peanuts from Africa are imported by many European countries. Peanuts have also become an important, clinically recommended form of protein today — unless of course one is allergic to nuts.The peanut, grown mainly for human consumption, has several uses, as whole seeds or processed to make peanut butter, oil and other products.
Peanuts are classified as a legume botanically and as a fat, which is considered the ‘good’ fat by global nutritionists’.
Peanuts are equally highly digestible and aid nutrient absorption in the body.
This important food and oil crop is currently grown on approximately 42 million acres worldwide.
It is the third major oilseed of the world after soybean and cotton (FAO, 1990). India, China and the US have been the leading producers for over the past several decades and grow about 70 percent of the world’s crop.
In the US, peanut farmers produce around three million tonnes of peanuts annually on approximately 1,5 million acres.
The major peanut producing states here are Georgia, Texas, Alabama, North Carolina, Florida, Oklahoma, Virginia, New Mexico, Arkansas, Mississippi and South Carolina where they produced four main types of peanuts, namely Runner, used primarily for the manufacture of peanut butter; Virginia, marketed mainly as snack peanuts and in-shell peanut products; Spanish, with rounder and smaller kernels, used for snack nuts, peanut butter and confections; and Valencia, which contains three-five kernels per shell, marketed mostly in the shell for roasting and boiling.
This means they enjoy the best of both worlds, containing key nutrients found in both the legume and nut families. Peanuts contain approximately 80 percent unsaturated fat
Nutrient-dense peanuts (and peanut butter) are protein powerhouses, containing more protein than any other nut and providing approximately 15 percent of daily protein needs, including many vitamins and minerals dietary fibre.
They contain 25-30 percent protein (average of 25 percent digestible protein) and 42-52 percent oil.
One kilogramme of peanuts is high in food energy and provides approximately the same energy value as two kilogramme of beef, 1,5 kg of cheddar cheese, nine litres of milk or 36 medium size eggs.
Peanut kernels are widely consumed as snack food in in many countries, including Zimbabwe and can be processed in a variety of ways (for example peanut butter, roasted, fried and salted or liquidised).
The peanut is versatile; in the early 1900s, over 300 uses for the peanut plant were found by a research scientist. He became known as the ‘the father of the modern peanut industry’.
The plant is an annual herbaceous plant that grows to a maximum height of 60 cm.
It is characterised by bearing of fruits that develop and mature underground; elongated stalk (pegs) can attain a length of 15-30 cm.
Once penetration of the soil surface has occurred, fruit enlargement proceeds at the peg tip with eventual formation of the peanut pod. Pods can contain one-six seeds.
Peanuts are divided into two main species; hypogaea and fastigiata, based on the arrangement of the vegetative and reproductive branches.
The hypogaea species does not flower on the main stem; it matures later than other sub-species and has a high-water requirement. It has alternate branching patterns and produces large seeds. Virginia and runner types are in the hypogaea sub-species.
The fastigiate species produce flower on the main stem, has sequential branching, mature earlier, has lower water requirement and produces smaller seeds. Spanish and Valencia are in this sub-species.
In Zimbabwe, the peanut may be divided into three types, according to the time taken to maturity — early, medium and late maturing.
The two sought after short season varieties are mwenje and nyanda which take about 115 days or less to maturity. Both are drought stress tolerant and resistant to aphids, Hilda and grain moth. Late maturing groundnuts take about 160 days to maturity.
Groundnuts grow in sandy, loamy soils, and require 120-160 frost free days. Soils that are well drained, loosely textured and well supplied with calcium, potassium and phosphorous are best for peanut cultivation.
The soil should be well aerated and contain moderate amounts of organic matter. Heavier clay soils or those that tend to have surface crusting are unsuitable due to their high resistance to peg penetration and pod expansion.
Peanut/ groundnuts grows best in slightly acidic soils with a pH of 6.0-6.5. Saline soils are not suitable since peanut has a very low salt tolerance. Low levels of calcium soils result in peanut partial filling out or not at all, resulting in ‘wind nut’ formation.
Groundnut/peanut seed require a lot of water during germination. For optimum germination, high soil moisture is required to facilitate the 35-40 percent water intake by imbibing seeds. Seeds should be planted when moisture levels are favourable for rapid germination and growth.
Rapid germination and vigorous growth help the young plant to counteract diseases.
Good land preparation is critical for maximum moisture retention, precision planting, fast uniform seed germination and emergence and effective weed and disease control. On virgin soils, clearing and leveling is necessary. limestone should be applied at least four weeks before planting.
The first tillage should take place six weeks before planting, using a disc plough. This tillage involves deep turning of the soil 20-30 cm in depth to completely bury weed seed and incorporate crop residues.
The second tillage operation is conducted using a spike harrow in order to create a suitable seedbed that is loose, smooth and level.
However, heavy equipment is not recommended for leveling since these contribute to soil compaction.
Groundnut seed requirements are about 100kg per hectare. Seed should be planted at a spacing of 35- 45cm between rows and 5-10cm between seeds in the row at a depth of 5cm.
Peanut/groundnut crops are attacked by a wide variety of insect and mite pests.
The main insects that attack peanuts are the leaf-feeding caterpillar, thrips, stalk borer, leaf-eating ants, bean and flea beetle, aphids and leaf miner.
Root-knot nematodes exist in the soil in the form of eggs or larvae that feed on the root tissue.
Weeds are also a major problem for peanuts, especially during the first 4-8 weeks.
They reduce yields by competition, and interference with harvest and by harbouring pests.
Ancient Zimbabwean agro-cultural practices, such as good land preparation and crop rotation, are still recommended practices to farmers today.
Crop rotation practices are recommended with non-leguminous crops (maize and sorghum) which have been well fertilised, because groundnuts respond well when fertiliser is applied to the previous crop.
Groundnuts are a good crop to grow before maize or within your maize crop.
Good quality groundnut seed is essential when planting. Seed quality is a combination of multiple attributes; referring mainly to genetic and physical purity, physiological and health quality which independently and in interaction with each other constitute the overall quality of seed. Investing in peanut farming reinvigorates your soil and your profits.
Dr Tony Monda is currently conducting veterinary epidemiology, agronomy, food security and agro-economic research in Zimbabwe and Southern Africa. He holds a PhD, DBA, DVM. E-mail tonym.MONDA@gmail.com