Teaching Organic Farming and Gardening

Irrigation

30 | Unit 1.5

Appendix 5: Amount of Water Needed to

Pre-Irrigate a Dry Soil to Different Depths

(Approximate)

1

SOIL tyPE^2 INcHES WAtER PER FOOt SOIL

DEPtH

INcHES WAtER tO REAcH 6 FEEt

DEEP

Clay 1.4–1.8 8.6–10.8

Silty clay 1.6–1.9 9.6–11.4

Sandy clay 1.6–1.9 9.6–11.4

Silty clay loam 2.2–2.3 13.0–13.7

Clay loam 2.0–2.2 12.2–13.0

Sandy clay loam 2.0–2.2 12.2–13.0

Silt-loam 1.8–2.0 10.8–12.2

Loam 1.7–1.9 10.1–11.4

Very fine sandy loam 1.7–1.9 10.1–11.4

Sandy loam 1.1–1.3 6.5–7.9

Loamy   very    fine    sand 1.1–1.3 6.5–7.9

Loamy   fine    sand 1.0–1.2 5.8–7.2

Loamy   sand 0.7–1.0 4.3–5.8

Very fine sand 0.7–1.0 4.3–5.8

Fine    sand 0.7–1.0 4.3–5.8

Sand 0.7–1.0 4.3–5.8

Coarse sand and gravel 0.4–0.7 2.2–4.3

(^1) Based on available water holding capacity; plants have dried soil to permanent wilting point, 15 ATM.
(^2) Assumes the soil is uniform throughout irrigation depth.
Appendix 5