Growing Napier Grass in Kirinyaga

Soil suitability analysis based on Kirinyaga's nutrient profile

Quick answer

Yes — Kirinyaga is well suited to Napier Grass. Kirinyaga's soil (pH 5.31, strongly acidic) gives Napier Grass a suitability score of 75/100. Apply agricultural lime before planting to unlock phosphorus and lift the score.

Kirinyaga County is well suited to Napier Grass, scoring 75/100 on ShambaIQ's soil-match model. Local soils average pH 5.31 — moderately acidic and inside the 5–8 band Napier Grass prefers, so no lime is usually required. Nitrogen (1.36 g/kg), phosphorus (12.5 mg/kg) and potassium (177 mg/kg) all meet Napier Grass's requirements, so a maintenance fertilizer programme is enough. Napier Grass prefers loam soils, while Kirinyaga is largely clay, so drainage and organic-matter management matter more here. At current prices (about KES 5/kg) and a typical 30,000 kg/acre yield, a well-managed Napier Grass crop here can gross roughly KES 150,000 per acre.

75Suitability score

Soil & climate match

FactorKirinyaga soilNapier Grass needsStatus
pH5.3158OK
Nitrogen1.36 g/kgmin 0.8 g/kgOK
Phosphorus12.5 mg/kgmin 6 mg/kgOK
Potassium177 mg/kgmin 150 mg/kgOK
Rainfall1,300 mm800–2,000 mmOK
Altitude1,500 m0–2,500 mOK

Top dressing guide

Product
CAN
Timing
After each cut
Instruction
Apply after every harvest cut to support rapid regrowth. Critical for maintaining high biomass yield.
Bags per Acre
0.5

Recommended seed varieties

Clone 13Medium/Highland
ICIPE/KALRO · 90-120 days · 10–15 tons/acre
Push-pull trap crop; high biomass; excellent fodder quality.
Kakamega 1Medium
KALRO · perennial days · 9–12.5 tons/acre
High dry matter yield; tolerant to head smut disease.

Economics

Market priceKES 5/kg
Expected yield in Kirinyaga28,125 kg/acre
Estimated revenueKES 140,625/acre
Adjusted for Kirinyaga's 75/100 suitability. Under ideal conditions Napier Grass can reach 30,000 kg/acre (~KES 150,000/acre) — attainable here only after the climate and soil constraints below are addressed.

Preferred textureLoam

Fertilizer prices

DAP
KES 3,500(6,500)
CAN
KES 2,875(4,500)
NPK 17:17:17
KES 3,275(5,600)
Urea
KES 3,500(5,500)
Lime
KES 1,500(1,800)

Green = subsidized · (Commercial) per 50kg bag