Growing Yams in Wajir

Soil suitability analysis based on Wajir's nutrient profile

Wajir County is a challenging environment for Yams (soil-match score 1/100) and will need significant amendment before planting. At an average pH of 8.4 the soil sits above Yams's preferred 5.5–6.5 range, which can limit uptake of phosphorus and micronutrients. The main gap is nitrogen — measured at N 0.52 g/kg, P 39.3 mg/kg, K 396 mg/kg against this crop's medium/medium/high demand — so the fertilizer plan below prioritises closing that deficit. The county's predominantly sandy soils suit Yams, which favours sandy loam. Wajir receives approximately 200 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.

1Suitability score

Soil match analysis

NutrientWajir soilYams needsStatus
pH8.45.56.5Adjust
Nitrogen0.52 g/kgmin 0.8 g/kgLow
Phosphorus39.3 mg/kgmin 12 mg/kgOK
Potassium396 mg/kgmin 200 mg/kgOK

Recommended seed varieties

Local White (Nyandarua/Meru)Medium/Highland 1000-1800m
Local · 240-300 days · 2.5–3.5 tons/acre
Traditional tuber crop; highly valued for food security; propagated via tuber sets.
Local PurpleMedium/Highland 1000-1800m
Local · 270-330 days · 2–3 tons/acre
Vigorous climbing vine; highly nutritious tuber.

Economics

Market priceKES 80/kg
Expected yield6,000 kg/acre
Estimated revenueKES 480,000/acre

Preferred textureSandy Loam

Fertilizer prices

DAP
KES 2,500(6,500)
CAN
KES 2,500(4,500)
NPK 17:17:17
KES 2,500(5,600)
Urea
KES 2,500(5,500)
Lime
KES 1,500(1,800)

Green = subsidized · (Commercial) per 50kg bag