Soil Data Methodology & Sampling Standards
Scientific rigor, laboratory calibration datasets, and agronomic rule modeling powering ShambaIQ's hyper-local soil recommendations.
Data Quality Commitment
ShambaIQ aggregates and harmonizes soil laboratory test samples across 47 Kenyan counties and 1,450+ wards. Our goal is to eliminate blanket fertilizer recommendations by providing farmers, agronomists, and agro-dealers with site-specific nutrient diagnostics.
All figures shown on soil pages are modelled 30 m satellite predictions, not laboratory tests. They are calibrated against ground-truth samples but should not be treated as a substitute for a certified soil test.
1. Primary Data Sources & Provenance
Our algorithms synthesize empirical datasets from leading national and international agricultural research institutions:
KALRO & National Agricultural Labs (NAL)
Soil spectral libraries, wet chemistry benchmarks, and historical fertility mapping.
Ministry of Environment & Forestry (MEF)
Agro-ecological zoning (AEZ) shapefiles, elevation bounds, and long-term rainfall patterns.
iSDA Africa / SoilGrids
30 m resolution satellite-derived soil property predictions (pH, nitrogen, phosphorus, potassium, organic carbon) used for ward-level and per-coordinate precision pages.
Certified Agro-Dealer Registry
KEPHIS & PCPB verified stockist listings for certified seeds, fertilizers, and lime distributors.
2. Parameters We Report — and What We Don't
Transparency means being explicit about the boundaries of our data:
✓ Parameters We Report
- Soil pH (H₂O)
- Total Nitrogen (g/kg)
- Extractable Phosphorus (mg/kg)
- Extractable Potassium (mg/kg)
- Organic Carbon (g/kg)
- Texture class
- Rainfall (mm/year) & Altitude (m)
✗ Parameters We Do NOT Report
- Calcium (Ca)
- Magnesium (Mg)
- Sulphur (S)
- CEC (Cation Exchange Capacity)
- Sodium / Aluminium toxicity
- Bulk density
- Sand / Silt / Clay percentages
iSDA can supply several of these, but we do not currently fetch or display them.
3. Soil Chemistry Calibration & Thresholds
All fertilizer recommendations are calculated against standard agronomic reference thresholds:
| Parameter | Testing Method | Optimal Range | Action Threshold |
|---|---|---|---|
| Soil pH (H₂O) | 1:2.5 Soil-Water Ratio | 6.0 – 6.8 | pH < 5.5 (Liming Required) |
| Nitrogen (N) | Kjeldahl Method / Total N | 0.2% – 0.5% | < 0.15% (Apply CAN / UREA) |
| Phosphorus (P) | Mehlich-1 Extraction | 30 – 80 ppm | < 20 ppm (Apply DAP / NPK 23:23:0) |
| Potassium (K) | Ammonium Acetate pH 7.0 | 0.24 – 1.5 meq/100g | < 0.2 meq (Apply MOP / NPK) |
4. Editorial Standards & Expert Verification
All rule models, crop suitability indexes, and fertilizer formulas undergo review before deployment to our programmatic data layer.