Growing Sweet Potato in Samburu

Soil suitability analysis based on Samburu's nutrient profile

Samburu County is a challenging environment for Sweet Potato (soil-match score 18/100) and will need significant amendment before planting. At an average pH of 8.28 the soil sits above Sweet Potato's preferred 4.5–7 range, which can limit uptake of phosphorus and micronutrients. Nitrogen (0.67 g/kg), phosphorus (42.1 mg/kg) and potassium (387 mg/kg) all meet Sweet Potato's requirements, so a maintenance fertilizer programme is enough. The county's predominantly sandy soils suit Sweet Potato, which favours sandy loam. Samburu receives approximately 350 mm/year — well below Sweet Potato's minimum of 600 mm — so supplemental irrigation would be essential for this crop. Sweet Potato's full potential is about 5,000 kg/acre (~KES 90,000/acre at KES 18/kg), but at Samburu's 18/100 suitability a realistic target here is closer to 1,125 kg/acre (~KES 20,250/acre) unless the constraints above are addressed.