🇪🇷 Eritrea Irrigation Water Calculator

Reference Evapotranspiration (ETo) measures how much water evaporates from soil and transpires through plants under standard conditions. It varies by climate zone — arid regions like the Sahel have higher ETo than humid tropical zones.

Crop Coefficient (Kc) adjusts ETo for each crop and growth stage. At flowering, most crops have their highest water demand (Kc = 1.0–1.2). During germination and maturity, demand is lower.

Effective Rainfall is the portion of rain that actually reaches crop roots. Not all rainfall is usable — some runs off, some evaporates. The USDA SCS method estimates this from monthly totals.

Irrigation Efficiency varies dramatically by method. Drip irrigation delivers 90% of water to crops, while flood irrigation loses 60% to evaporation and runoff. Upgrading your method can cut water use by half.

• Mulching: Apply 5–10 cm of organic mulch to reduce soil evaporation by 25–50%.
• Deficit Irrigation: Reducing water by 20% during vegetative stage has minimal yield impact for many crops.
• Schedule by Need: Water early morning or evening to reduce evaporation losses.
• Soil Improvement: Adding organic matter increases water-holding capacity, reducing irrigation frequency.
• Rainwater Harvesting: Collect rooftop and surface runoff for supplemental irrigation during dry spells.