Growing Yams in Tharaka Nithi
Soil suitability analysis based on Tharaka Nithi's nutrient profile
Possible but challenging — Tharaka Nithi is only marginally suited to Yams. Tharaka Nithi's soil (pH 4.99, strongly acidic) gives Yams a suitability score of 44/100. Apply agricultural lime before planting to unlock phosphorus and lift the score.
Tharaka Nithi County is a challenging environment for Yams (soil-match score 44/100) and will need significant amendment before planting. At an average pH of 4.99 the soil is strongly acidic, below Yams's preferred 5.5–6.5 range; agricultural lime will lift pH and unlock phosphorus the crop cannot otherwise access. Nitrogen (1.23 g/kg), phosphorus (19.6 mg/kg) and potassium (211 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. On ShambaIQ's soil-match model, Yams is the #87 soil match of the 106 crops we assess for Tharaka Nithi County. Yams's full potential is about 7,000 kg/acre (~KES 560,000/acre at KES 80/kg), but at Tharaka Nithi's 44/100 suitability a realistic target here is closer to 3,850 kg/acre (~KES 308,000/acre) unless the constraints above are addressed.
Better matched to Tharaka Nithi's soil: Avocado, Macadamia, and Cassava — each scores higher on the same soil.
Soil & climate match
| Factor | Tharaka Nithi soil | Yams needs | Status |
|---|---|---|---|
| pH | 4.99 | 5.5–6.5 | Adjust |
| Nitrogen | 1.23 g/kg | min 0.8 g/kg | OK |
| Phosphorus | 19.6 mg/kg | min 12 mg/kg | OK |
| Potassium | 211 mg/kg | min 200 mg/kg | OK |
| Rainfall | 900 mm | 1,200–1,800 mm | Low |
| Altitude | 1,100 m | 0–1,800 m | OK |
Recommended seed varieties
Economics
Fertilizer prices
Green = subsidized · (Commercial) per 50kg bag