Groundnut

Groundnut is grown as an annual oilseed and food legume whose distinctive underground pod development sets it apart agronomically from nearly all other major crops, most notably in its strong preference for loose, easily penetrated soil.

Production spans smallholder systems, especially across parts of Africa and Asia, to large mechanized operations in the Americas, with cultivar choice shaped by market use — confectionery, oil extraction, or roasting.

Family

Fabaceae (legume family)

Genus and species

Arachis hypogaea

Reproductive habit

Geocarpic: pollinated flowers form a peg that pushes the developing pod underground to mature

Groundnut was domesticated in South America, in the region of present-day Bolivia, Argentina, and Paraguay, and was subsequently spread by European traders to Africa and Asia, where it became deeply integrated into food systems and, in turn, was reintroduced to North America.

It is now grown pantropically and in warm temperate regions worldwide. Current statistics on planted area, production, and trade by country are compiled by FAO and national agricultural agencies.

Groundnut is a warm-season crop requiring a long frost-free period to complete its cycle, with germination, pegging, and pod development all favored by warm soil and air temperatures.

The crop is sensitive to cold, particularly during establishment and again during pod-fill, and planting timing is set locally to ensure the growing season provides sufficient warm days for pod maturation.

Loose, well-drained sandy soils are strongly preferred because pegs must penetrate the soil easily for pods to form normally, and because pods are dug directly from the soil at harvest — heavier or compacted soils impede pegging and complicate clean harvest.

Groundnut is typically direct-seeded from shelled kernels, with row spacing set according to growth habit (bunch or runner). Rotation with cereals is recommended to manage the buildup of soilborne pathogens over time.

• Growth habit selection (bunch or runner) matched to local row-spacing and harvest equipment
• Crop rotation with cereals to manage soilborne diseases
• Maintaining loose, friable soil in the pegging zone through appropriate tillage
• Timely weed management, since groundnut competes poorly with weeds during early growth

Biological nitrogen fixation can supply much of the crop’s nitrogen requirement where nodulation is effective. Calcium availability specifically within the pegging and pod zone is particularly important for groundnut, since calcium for pod and kernel development is absorbed directly by the developing pod rather than primarily through the roots.

Flowering, pegging, and pod-fill are all moisture-sensitive stages in groundnut. In some regions, drought stress late in the season has also been linked to an increased risk of fungal contamination associated with aflatoxin, a recognized food-safety concern managed through variety choice, timely harvest, and proper drying and storage.

Crop water requirements are estimated from evapotranspiration and local climate data, following reference methods published by FAO and national agricultural agencies.

Root rot can develop in wet or compacted soils, and anthracnose has been documented affecting groundnut foliage and pods in some regions. Thrips are a major pest, feeding directly on foliage and acting as vectors for certain plant viruses, while aphids are also present in many production areas.

Management combines resistant cultivars, crop rotation, field monitoring, and, where warranted, locally authorized control measures applied according to their labels.

Plants are lifted or dug once pods reach maturity, assessed by internal shell coloration and pod fill, since maturity cannot be judged from the foliage alone. After lifting, pods are dried before threshing, further drying, and storage — a critical step for both quality and safe storage.

• Crushed for edible groundnut (peanut) oil
• Direct food consumption — roasted, boiled, or processed into peanut butter and confectionery
• Protein meal by-product used in animal feed
• Haulm (vines) used as forage or fodder in some production systems