Drip irrigation is often promoted as a water-saving technology, but how much does it actually save? And does the cost savings justify the investment? In this article, we walk through a real calculation for a 5-hectare tomato farm using our irrigation calculators.
Let's compare two irrigation systems for a 5-hectare tomato farm in a Mediterranean climate with 5mm/day peak ETc:
Peak daily water requirement (net): 5mm/day × 5ha × 10m³/ha/mm = 250 m³/day
Flood irrigation: 250 ÷ 0.55 = 455 m³/day applied
Drip irrigation: 250 ÷ 0.90 = 278 m³/day applied
Daily water savings: 455 - 278 = 177 m³/day (39% less water)
Over a 120-day growing season: 177 × 120 = 21,240 m³ saved per season. That's enough water to grow an additional 2 hectares of tomatoes!
Pumping water requires energy. Let's assume: water source is 20m below ground, pump efficiency 60%, diesel cost $1.20/L, electricity cost $0.12/kWh.
Flood (diesel): 455 m³/day × 20m × 9.81 kPa/m ÷ (0.60 × 3.6 MJ/kWh) ÷ 38 MJ/L diesel = ~2.6 L diesel/day = $3.12/day
Drip (electric): 278 m³/day × 20m × 9.81 ÷ (0.60 × 3.6) = ~25.2 kWh/day = $3.02/day
Energy costs are similar, but the drip system uses 39% less water. In areas with water scarcity or water pricing, the savings are substantial. If water costs $0.50/m³, flood irrigation costs $227/day vs drip $139/day — a savings of $88/day, or $10,560 per season.
Beyond water savings, drip irrigation typically increases yields by 15-30% due to: consistent soil moisture (no wet-dry cycles), reduced disease (foliage stays dry), precise nutrient application (fertigation), and better weed control (water only where crops are). For our tomato farm at 40 tons/ha baseline, a 20% yield increase = 8 extra tons/ha × 5ha = 40 tons × $800/ton = $32,000 additional revenue.
Drip irrigation system cost: ~$3,000-5,000/ha (including filters, pumps, tubing, emitters). For 5ha: $15,000-25,000. Annual savings (water + yield increase): $10,560 + $32,000 = $42,560. Payback period: less than 1 season.
Use our Irrigation Calculator and Drip System Designer to calculate savings for your specific farm. Read our complete drip irrigation design guide for system planning.
Put these concepts into practice with our free agricultural calculators.
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