Growing Oilseed Rape (Canola) in Tharaka Nithi

Soil suitability analysis based on Tharaka Nithi's nutrient profile

Tharaka Nithi County is a challenging environment for Oilseed Rape (Canola) (soil-match score 34/100) and will need significant amendment before planting. At an average pH of 4.99 the soil is strongly acidic, below Oilseed Rape (Canola)'s preferred 5.8–7.5 range; agricultural lime will lift pH and unlock phosphorus the crop cannot otherwise access. The main gap is phosphorus — measured at N 1.23 g/kg, P 19.6 mg/kg, K 211 mg/kg against this crop's high/high/medium demand — so the fertilizer plan below prioritises closing that deficit. The county's predominantly sandy loam soils suit Oilseed Rape (Canola), which favours loam. Oilseed Rape (Canola)'s full potential is about 1,000 kg/acre (~KES 60,000/acre at KES 60/kg), but at Tharaka Nithi's 34/100 suitability a realistic target here is closer to 425 kg/acre (~KES 25,500/acre) unless the constraints above are addressed.