📅 Irrigation Schedule Calculator — Days Between Irrigations
Calculate optimal irrigation intervals based on soil type, rooting depth, and crop water use. Avoid over or under-watering.
Quick answer: Days between irrigations = Readily available water ÷ Daily crop water use. Sandy loam, 0.5m root depth, 6mm/day crop use = 5 days between irrigations.
📅 Calculate Irrigation Schedule
Wheat 0.5-1m, Maize 1-1.5m, Pasture 0.3-0.5m
Summer crops 6-10mm, Winter crops 3-5mm
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Days Between Irrigations
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Readily Available Water (mm)
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Weekly Water Requirement
📐 How Irrigation Schedule Is Calculated
Total available water = Soil water holding capacity × Rooting depth Readily available water = Total available water × 0.5 (50% depletion) Days between irrigations = Readily available water ÷ Daily crop water use
Identify soil type — determines water holding capacity
Measure rooting depth — depends on crop and soil
Calculate readily available water — 50% of total available
Divide by daily crop use — gives irrigation interval
📊 Worked Example
Sandy loam (65mm/m), rooting depth 0.5m, summer crop using 6mm/day.
Total water = 65 × 0.5 = 32.5mm Readily available = 32.5 × 0.5 = 16.25mm Days between = 16.25 ÷ 6 = 2.7 days ≈ every 3 days
Apply 16mm every 3 days. In sandy soil, more frequent lighter irrigations are better (every 2 days, 12mm).
❓ Frequently Asked Questions
Days between irrigations = Readily available water ÷ Daily crop water use. Example: Sandy loam 60mm/m × 0.5m roots = 30mm RAW ÷ 6mm/day = 5 days.
Start when 40-50% of available water is depleted. Use soil moisture probes or tensiometers. Visual cues: leaf rolling, colour change. Don't wait until wilting.