Growing Arrow Root in Lamu

Soil suitability analysis based on Lamu's nutrient profile

Quick answer

Generally not ideal — Lamu is poorly suited to Arrow Root. Lamu's soil (pH 6.31, slightly acidic) gives Arrow Root a suitability score of 30/100. Match fertilizer to Lamu's nitrogen and phosphorus levels for the best result.

Lamu County is a challenging environment for Arrow Root (soil-match score 30/100) and will need significant amendment before planting. Local soils average pH 6.31 — slightly acidic to near-neutral and inside the 5–7 band Arrow Root prefers, so no lime is usually required. The main gap is nitrogen, phosphorus, and potassium — measured at N 0.74 g/kg, P 9.6 mg/kg, K 117 mg/kg against this crop's medium/medium/high demand — so the fertilizer plan below prioritises closing those deficits. Arrow Root prefers clay loam soils, while Lamu is largely sandy, so drainage and organic-matter management matter more here. Lamu receives approximately 600 mm/year — well below Arrow Root's minimum of 1000 mm — so supplemental irrigation would be essential for this crop. Arrow Root's full potential is about 5,000 kg/acre (~KES 275,000/acre at KES 55/kg), but at Lamu's 30/100 suitability a realistic target here is closer to 1,875 kg/acre (~KES 103,125/acre) unless the constraints above are addressed.

30Suitability score

Soil & climate match

FactorLamu soilArrow Root needsStatus
pH6.3157OK
Nitrogen0.74 g/kgmin 0.8 g/kgLow
Phosphorus9.6 mg/kgmin 12 mg/kgLow
Potassium117 mg/kgmin 200 mg/kgLow
Rainfall600 mm1,000–2,000 mmLow
Altitude10 m0–1,800 mOK

Top dressing guide

Product
CAN
Timing
3 months after planting
Instruction
Apply in a ring around the plant. Arrow Root is a long-season crop and benefits from one mid-season application.
Bags per Acre
0.5

Recommended seed varieties

Nduma LocalMedium/Highland
KALRO · 270-365 days · 2.5–4 tons/acre
Traditional variety; good corm size; suited to wet highland areas.

Economics

Market priceKES 55/kg
Expected yield in Lamu1,875 kg/acre
Estimated revenueKES 103,125/acre
Adjusted for Lamu's 30/100 suitability. Under ideal conditions Arrow Root can reach 5,000 kg/acre (~KES 275,000/acre) — attainable here only after the climate and soil constraints below are addressed.

Preferred textureClay Loam

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