Growing Yams in Machakos

Soil suitability analysis based on Machakos's nutrient profile

Machakos County is a challenging environment for Yams (soil-match score 26/100) and will need significant amendment before planting. At an average pH of 7.03 the soil sits above Yams's preferred 5.5–6.5 range, which can limit uptake of phosphorus and micronutrients. Nitrogen (0.82 g/kg), phosphorus (31.4 mg/kg) and potassium (338 mg/kg) all meet Yams's requirements, so a maintenance fertilizer programme is enough. The county's predominantly sandy loam soils suit Yams, which favours sandy loam. Machakos receives approximately 700 mm/year — well below Yams's minimum of 1200 mm — so supplemental irrigation would be essential for this crop. At current prices (about KES 80/kg) and a typical 6,000 kg/acre yield, a well-managed Yams crop here can gross roughly KES 480,000 per acre.