In irrigation scheduling based on evapotranspiration, what does ET primarily guide?

In irrigation scheduling based on evapotranspiration, what does ET primarily guide?

• A. The rainfall rate used to decide when to water
• B. The soil type that determines root depth
• C. The schedule of fertilizer applications
• D. The amount of water to apply to meet plant needs without overwatering

Answer: (D)

ET tells you how much water the crop uses and therefore how much you need to replenish. In irrigation scheduling, the goal is to replace the water lost by the plant in a given period so the root zone stays moist enough for growth without becoming waterlogged. So ET primarily guides the amount of water to apply to meet plant needs and avoid overwatering. Rainfall and soil type influence how you implement that amount, but ET itself is about crop water use, not when to apply rainfall or what soil properties are, and it isn’t about fertilizer timing. On hot, dry days ET rises, so you apply more water; when rainfall occurs or ET is low, you reduce the irrigation.

ET tells you how much water the crop uses and therefore how much you need to replenish. In irrigation scheduling, the goal is to replace the water lost by the plant in a given period so the root zone stays moist enough for growth without becoming waterlogged. So ET primarily guides the amount of water to apply to meet plant needs and avoid overwatering. Rainfall and soil type influence how you implement that amount, but ET itself is about crop water use, not when to apply rainfall or what soil properties are, and it isn’t about fertilizer timing. On hot, dry days ET rises, so you apply more water; when rainfall occurs or ET is low, you reduce the irrigation.