Whether you’re a seasoned farmer or a beginner looking to enter the sector, groundnuts, also known as peanuts, present an excellent opportunity. This widely consumed and economically significant crop balances low production costs with high market demand.
Stephen Kinyua, an agricultural consultant with a passion for communal livelihoods as well as extensive experience in land evaluation and agro-biodiversity conservation, unpacks the fundamentals of groundnut farming. He highlights that the crop requires minimal input while offering high economic returns.
Soil and climate requirements
Groundnuts prefer sandy loam soils with good drainage and an optimal pH of 5.5 to 7.0. The crop requires warm temperatures between 20°C and 30°C, with a frost-free period of 100 to 130 days to ensure proper growth and maturity.
According to a publicly available guide compiled by the Agricultural Research Council (ARC), groundnuts in South Africa are generally planted between mid-October and mid-November. However, the precise planting date varies based on several factors, with rainfall being the most crucial consideration.
Kinyua stresses the importance of soil conditions. “Groundnuts do best in well-drained sandy loam soils. Poor drainage can lead to rotting of the pods, significantly reducing yields.”
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Groundnut varieties
Kinyua explains that groundnut varieties are categorised into four main groups as follows:
- Runner: Valued for their high oil content and commonly used in peanut butter and various processed products.
- Virginia: Large kernels, ideal for roasting.
- Spanish: Smaller seeds, commonly used in peanut butter and snacks.
- Valencia: Sweet flavour, often containing three to four seeds per pod.
According to the department of agriculture, South Africa has a limited number of registered groundnut cultivars, but ongoing research aims to develop improved varieties. For a comprehensive list of registered cultivars suited for their region, farmers should consult local extension officers and seed suppliers.
The South African Groundnut Forum provides detailed insights on the current registered commercial cultivars.
Planting guidelines
Proper spacing and planting depth are key to healthy crop establishment. Kinyua advises that “seeds should be planted about 5cm deep, with a spacing of 15-20cm between plants and 45-60cm between rows to allow proper root development and easy harvesting”.
Pest and disease management
Groundnuts are susceptible to various pests and diseases that can significantly impact yield if not properly managed. Among the most common pests are aphids, which transmit viral diseases; thrips, which cause leaf damage and stunt plant growth; and nematodes, which attack the roots, reducing nutrient absorption.
Additionally, groundnut crops are vulnerable to diseases such as leaf spot, which leads to premature leaf fall and lower productivity, and rust, a fungal infection that causes yellowing and wilting.
To mitigate these challenges, Kinyua advises that “farmers should practise crop rotation, use resistant varieties, and apply fungicides when necessary to prevent the spread of diseases”.
Harvesting groundnuts
Harvesting occurs when the pods are fully mature, typically 90 to 130 days after planting, depending on the variety and growing conditions. Farmers should monitor pod colour and texture to determine the right time for harvesting.
“Proper timing of harvesting is crucial. If harvested too early, the pods will not have fully developed. If delayed, they may begin to sprout underground, reducing quality,” stresses Kinyua.
He explains that the harvest process involves uprooting plants, allowing them to dry, and then separating the pods before storage or sale.
Effective irrigation methods
Farmers can use different irrigation techniques to optimise water use:
- Drip irrigation: Reduces water wastage by directly targeting plant roots.
- Sprinkler irrigation: Suitable for sandy soils, and ensures uniform water distribution.
- Furrow irrigation: A traditional method where water is channelled along crop rows.
Proper irrigation management is crucial, as too much water can lead to root rot, while inadequate moisture can stunt plant growth and decrease yields. Farmers must carefully monitor water application to prevent these issues and ensure optimal crop development.
“Soil moisture sensors or simple field tests can help determine when irrigation is needed,” says Kinyua.
Critical irrigation stages
Groundnuts need adequate water supply at key growth stages to ensure healthy development and maximise yields. The key growth stages that require careful water management are as follows:
- Germination stage: Farmers need to ensure uniform seedling emergence.
- Flowering stage: Water stress at this stage can reduce flower formation.
- Pod development stage: Moisture is essential for proper pod filling.
“Groundnuts need consistent moisture during pod development. Drought stress at this stage can result in small, shrivelled nuts,” says Kinyua.
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