Kersting's groundnut (Macrotyloma geocarpum) is a rare and underexploited leguminous crop cultivated in parts of West Africa, which now faces extinction. A study was conducted in northern Ghana, which falls within the Guinea Savannah ecological zone, to establish the status of the crop, its production constraints and prospects for its future development or improvement. Sixteen types of Kersting's groundnut were collected which could be distinguished by three seed colours. It is predominantly grown on a small scale (0.1-0.5 acre) as a sole crop, but is often intercropped with other food crops. Pest and disease are not a significant constraint in the cultivation of Kersting's groundnut. Over-tasked farmers harvest it late when the soil has hardened, and this has been the main constraint to its largescale production. Variation in seed size exists and could be used for crop improvement.

Twelve landraces of kersting's groundnut (Kerstingiella geocarpa Harms), collected from northern Ghana in 2004 were evaluated for plant height, canopy spread, leaf area index, nodule count, days to 50% flowering, fresh and dry shoot weight, fresh and dry root weight, pod number per plant, grain yield and hundred seed weight. The following parameters were similar (p > 0.05) among the landraces: leaf area index, nodule count at 7 and 9 WAP, dry shoot weight at 7 WAP, fresh and dry shoot weight at 7 WAP, number of pods per plant and hundred seed weight. Plant height at 8 WAP significantly varied (p = 0.026) among the landraces. The landraces Boli, Heng milk mottled, Gbangu, Nakori and Puffeon produced the tallest plants. Canopy spread of Heng red mottled, Heng milk mottled, Boli, Nakori, Nankpaduri, Puffeon and Gbangu exceeded other entries at 9 WAP. Days to 50% flowering varied significantly (p = 0.001) among landraces with Puffeon, Gbangu, Heng milk mottled, Nakori and Heng red mottled flowering early. At 7 WAP, fresh shoot weight was significantly (p = 0.002) different among the landraces with Heng milk mottled, Funsi, Nankpaduri, Boli, Sigiri, Dugulatuk, and Gbangu outstanding. Grain yield was highly significant (p = 0.001) with Heng red mottled, Funsi, Puffeon, and Sigiri as best yielders. Six Principal components (PC) were significantly informative in a factor analysis. The PC1 contained 90.76% of the total variation in the collection. A cluster analysis revealed that the measured traits accounted for only 12% of the variation with two major clusters.

Peanut (Arachis hypogaea L.) yield and financial returns are often low for smallholder farmers in Ghana.  Additionally, aflatoxin concentration in foods derived from peanut can be high enough to adversely affect human health.  Eight experiments were conducted in 2016 and 2017 in northern Ghana to compare yield, financial returns, pest reaction, and aflatoxin contamination at harvest with traditional farmer versus improved practices.  Relative to the farmer practice, the improved practice consisted of weeding one extra time, applying local potassium-based soaps to suppress arthropods and pathogens, and application of either homogenized oyster shells or a commercial blend of fertilizer containing calcium.  Each of these field treatments were followed by either drying peanut on the soil surface and storing in traditional poly bags or drying peanut on tarps and storing in hermetically-sealed bags for 4 months.  Peanut yield and financial returns were significantly greater when a commercial blend of fertilizer or oyster shells were applied compared to the farmer practice of not applying any fertilizer.  Yield and financial returns were greater when a commercial fertilizer blend was applied compared with oyster shells.  Severity of early leaf spot [caused by <em>Passalora arachidicola</em> (Hori) U. Braun] and late leaf spot [caused by <em>Nothopassalora personata</em> (Berk. & M.A. Curtis) U. Braun, C. Nakash., Videira & Crous], scarring and penetration of pods by arthropods, and the number of arthropods at harvest were higher for the farmer practice than for either fertility treatment; no difference was noted when comparing across fertility treatments.  Less aflatoxin was observed for both improved practices in the field compared with the farmer practice.  Drying peanut on tarps resulted in less aflatoxin compared to drying peanut on the ground regardless of treatments in the field.  Aflatoxin concentration after storage was similar when comparing post-harvest treatments of drying on soil surface and storing in poly bags vs. drying on tarps and storing in hermetically-sealed bags. These results demonstrate that substantial financial gain can be realized when management in the field is increased compared with the traditional farmer practice.

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The cereal–legume cropping system is a common practice across the tropical world. However, there are limited quantitative data on the effect of cereal–legume intercropping on weed species diversity. A study was conducted in the Guinea savanna zone of Ghana to evaluate the effect of maize–soybean intercropping on yield productivity and weed species control. The treatments used include three maize maturity types (extra‐early: Abontem, early: Sammaz 27 and medium: Obatanpa) intercropped with soybean at three intraspacing (10, 20 and 30 cm), and their sole crop treatments were laid in a randomized complete block design with three replications. Results showed that the land equivalent ratio (LER) for the intercrops was above 1, indicating better intercrop productivity than the sole crops. An average of 40% land was saved for the intercrops compared with the sole crops. Intercropping Sammaz 27 maize with soybean significantly increased LER by 9% compared to the other types. Intercropping maize with soybean significantly reduced weed biomass at 6 and 9 weeks after planting (WAP) and at harvest relative to the sole maize. The weed biomass at 6 and 9 WAP and harvest increased (p < .05) with increasing soybean intraspacing. The grass and broadleaf weed species count at 6 WAP and harvest from the sole crops were significantly higher than that of the intercrops. The results suggest that intercropping early maize maturity type with soybean at 10 cm intraspacing could be used to increase grain yield, LER and control of grass and broadleaf weeds in a maize‐based cropping system in the Guinea savanna zones of West Africa.