Soil Science

Soil Science Cheat Sheet: pH, CEC, and Nutrient Availability

Quick-reference guide covering soil texture, pH effects on nutrients, CEC, and fertilizer calculations. Perfect for last-minute review.

LisensyaPrep Team•April 5, 2025•4 min read

Soil Texture Triangle

The three primary soil separates: Sand (0.05–2 mm), Silt (0.002–0.05 mm), Clay (<0.002 mm).

Ideal texture: Sandy Clay Loam or Clay Loam for most crops.

pH Range	Condition	Effect on Crops

|----------|-----------|-----------------|

CEC measures the soil's ability to hold cations (positively charged nutrients). Higher CEC = better nutrient retention.

•Sand: 2–5 meq/100g

•Clay: 20–60 meq/100g

•Organic matter: 200+ meq/100g

•Nitrogen — yellowing of older leaves first

•Phosphorus — purple/reddish discoloration of leaves

•Potassium — leaf scorch (brown edges, older leaves)

•Calcium — blossom-end rot in tomatoes, tip burn

•Magnesium — interveinal chlorosis (younger/older leaves)

•Iron — interveinal chlorosis of young leaves

•Lime (CaCO3) — raises pH in acidic soils

•Sulfur — lowers pH in alkaline soils

•Gypsum (CaSO4) — improves soil structure, adds Ca/S without changing pH

•Organic matter/compost — improves all soil properties

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