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Groundnut production: A big driver of nutrition

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Mr Gerald Ssendaula examines the pods of a groundnut plant in his garden as he explains how to use legumes to boost fertility at his farm. Photo/Michael J Ssali

The main reason Gerald Ssendaula, a former minister of Finance, grows groundnuts is to have them as part of the diet in his household at Kyabbogo village in Masaka City. “I grow them because we eat them as a very good sauce and we also sometimes enjoy eating them roasted along with coffee,” he said during a conversation with Seeds of Gold recently during a tour of his farm.

Dr David Kalule Okello, principal research officer and plant breeder-geneticist at NaSARRI, told Seeds of Gold, “Groundnut is a highly nutritious food crop which is easily accessible to most people and is fast becoming a cash crop. Since it does not take long to prepare groundnut sauce, a lot of people prefer purchasing it because it does not take a lot of charcoal or firewood to prepare it. It is quite affordable to poor people.”

Dr Okello and a team of other researchers have produced a groundnut production manual in which it is stated that groundnut seeds contain 40-50 percent oil, 20-50 percent protein and 10-20 percent carbohydrates depending on the variety. “With the costs of animal protein becoming increasingly prohibitive, groundnut is becoming an even more important source of protein,” reads the manual. “Groundnut seeds are rich in vitamin E, niacin, falacin, calcium, phosphorus, magnesium, zinc, iron, riboflavin, thiamine, and potassium. One kilogramme of groundnuts provides approximately the same energy value as two kilogrammes of beef, 1.5 kilogrammes of cheddar cheese, nine litres of milk or 36 medium size eggs,” says Dr Okello.

Groundnut is consumed raw, roasted, blanched, as peanut butter, crushed and mixed with traditional dishes as a sauce or as binyebwa, a cooked paste. It is also an excellent source of cooking oil and groundnut cake and haulms (straw, stems) are commonly used as animal feed.

Groundnuts thrive under low rainfall and as a legume it improves soil fertility by fixing nitrogen. “Therefore the crop generally requires few inputs, making it appropriate for cultivation in low-input agriculture by smallholder farmers. As a cash crop, it gives relatively high returns for limited land area and is well adapted to the hot, semi-arid conditions of Uganda. These multiple uses of groundnut make it an excellent cash crop for domestic markets as well as for foreign trade,” says Dr Okello.

In 2019 Uganda produced 133,000 metric tonnes from an estimated planted area of 420,000 hectares according to the Uganda Bureau of Statistics. Teso produced 20000 metric tonnes, Acholi 15,000 and Lango 13,000 metric tonnes.

The crop’s value chain comprises input suppliers, seed dealers, and producers, rural traders, market sellers, processors, exporters and consumers.

Groundnuts according to Okello, grow best on friable soils that are well drained, well aerated, loosely textured and well supplied with calcium, potassium and phosphorus. He recommends that the farmers get certified seed of adapted varieties purchased from a reliable source.

He particularly recommended three new seed varieties released last February but are yet to be officially launched by the Minister of Agriculture and the Director General of National Agricultural Research Organisation (Naro).

He said Naro Holdings Ltd and a number of seed companies across Uganda are good sources of certified groundnut seeds. “A good amount of rain, evenly distributed annually, is required for good growth and yield. Early maturing small seeded varieties require 300-500mm while medium to late maturing large seeded varieties need 1000-1200mm rainfall.”

For farmers who save seed from previous harvests, Dr Okello recommends that the seeds should be pure (true to type or unadulterated), graded (medium size) undamaged, fully developed and free from discolouration and fungal infection with germination rate of above 90 percent. Germination tests on seeds should be carried out one week before sowing and the seed rate adjusted accordingly. He goes on to say that several other factors must be considered when deciding on a variety. They include, yield, resistance to major pests and diseases, grades, farmer preferences, seed colour, growth habit and maturity periods. Pods should be shelled 1-2 weeks before sowing and only good quality seed should be selected for sowing. He said groundnut seed has a high demand for water during germination. “For good germination, optimum soil moisture is required to facilitate the 35-40 percent water intake by imbibing seeds, “ Okello says.

“Seed 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.”

Groundnut seed is susceptible to a number of pathogens particularly fungi that cause seed decay and seedling death. Seed treatment prior to planting will protect the seed and seedlings from these pathogens and increase the plant stand in the field.

“Two seed dressing fungicides, Mancozeb and Thiram, are currently registered for use on groundnuts. Directions for use of these agents are indicated on the label.

Dr Okello recommends good land preparation for maximum moisture retention, precision planting, fast uniform seed germination and emergence and effective weed and disease control. He says land should be prepared early, maybe six weeks before planting, before the rains start, so that sowing can take place early in the rains.

“Groundnut does well in soils that are rich in organic matter. Fertilizer application should be guided by results of soil tests and the productivity levels targeted for the crop.” It is further generally recommended that farmers consult their area agricultural extension officers about which fertilisers to apply and how to apply them.

Okello also recommends sowing in rows and at the recommended spacing, which depends on the growth habit of the groundnut variety, botanical type, seed mass and germination rate of the seed-lot. Groundnuts may be planted at the spacing of 34 cm between rows and 10-15cm between plants. It is important to plant according to recommended spacing leaflets.

The farmer must uproot all weeds. Okello says weeds may significantly lower the groundnut yield by competition, interference with harvest and by harbouring pests and diseases as alternative hosts. At harvest time, some weed seeds will be harvested along with the groundnuts so that your seed will be contaminated with weed seed. “Groundnut is inherently a poor weed competitor particularly 3-6 weeks after sowing; therefore, effective early weed control implies good control of weed throughout the growing season and will translate into higher yields.”

Dr Okello discourages the practice of mounding soil around the plant in the hope that more pegs from higher nodes will enter the soil and increase the yield. He actually refers to this practice as an important yield limiting factor as it influences pod formation of the lower highly productive nodes and promotes growth of the stem rot causing fungus. It also deteriorates the quality of earlier set mature pods.

Disease control 
He says diseases and insect pests affect groundnut productivity and the quality of produce –poor pod filling, low shelling out-turn, small seed size, shriveled seed, discoloration, seed damage, and low germination rate. “There are a number of disease resistant measures, including the use of resistant cultivars, cultural, chemical and biological. Growing resistant/ tolerant cultivars is the most economical method.”

Groundnuts must be harvested at the right time. Premature harvesting can affect the yield and the quality of seeds. Yet delayed harvest after physiological maturity can lead to aflatoxin formation. He said the timing of the crop is very critical as it can significantly affect the yield and the quality of seeds.