How much fertilizer per acre in Kenya:Rates by crop, county, and soil type
The most common fertilizer question is also the most variable: how much do I use? A blanket answer of 1 bag DAP and 1 bag CAN is correct for highland maize but wrong for beans, wrong for onions in Kajiado, and wrong for any crop on unlimed acidic soils. This guide provides correct rates for Kenya's 10 most common crop-county combinations.
The most common fertilizer question is also the most variable: how much do I use? A blanket answer of 1 bag DAP and 1 bag CAN is correct for highland maize but wrong for beans, wrong for onions in Kajiado, and wrong for any crop on unlimed acidic soils. This guide provides correct rates for Kenya's 10 most common crop-county combinations.
Fertilizer rates for Kenya's 10 most common crops
| Crop | At planting | Top-dress | Lime needed? | Total cost/acre |
|---|---|---|---|---|
| Maize | DAP 50 kg | CAN 50 kg (knee height) | If pH < 5.8 | KES 7,700 |
| Wheat | DAP 75 kg | CAN 50 kg (tillering) | If pH < 6.0 | KES 9,800 |
| Beans | DAP 25 kg + Rhizobium | NONE | If pH < 5.5 | KES 3,500 |
| Cabbage | DAP 50 kg | CAN 50 kg × 2 (wk 3 + 6) | If pH < 5.5 | KES 11,700 |
| Tomato | DAP 50 kg | CAN 50 kg × 3 (wk 2, 5, 8) | If pH < 5.5 | KES 14,700 |
| Onion (Kajiado) | NPK 17:17:17 50 kg | AmSulfate 50 kg × 2 | No — alkaline | KES 10,400 |
| Potato | DAP 50 kg + MOP 25 kg | CAN 50 kg (earthing up) | If pH < 5.5 | KES 10,200 |
| Sweet potato | DAP 25 kg | Mavuno 25 kg (wk 4) | If pH < 5.5 | KES 5,600 |
| Sorghum | DAP 25 kg | CAN 25 kg (if rain good) | Rarely needed | KES 4,200 |
| Napier grass | DAP 50 kg (establish) | CAN 50 kg per cut (4-6/yr) | If pH < 5.5 | KES 16,000+/yr |
Costs exclude lime. Lime adds KES 10,500\u201335,000/acre depending on starting pH but amortises over 3\u20134 seasons. Get your exact fertilizer rate here.
Three expensive fertilizer mistakes
Applying CAN at planting instead of knee height
Cost: 15–30% nitrogen wasted
CAN volatilises from the surface before roots can absorb it. Wait until knee height when the established root system actively absorbs nitrogen during rapid growth.
Applying nitrogen fertilizer to beans
Cost: KES 3,500 wasted + reduced yield
Beans fix their own nitrogen through Rhizobium. External N suppresses nodule formation. Apply phosphorus only.
Applying DAP to alkaline Kajiado soils
Cost: pH rises further, zinc locks out
DAP's diammonium component releases hydroxide ions. Use NPK 17:17:17 and ammonium sulfate instead.
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