Management Allowed Depletion (MAD) is defined as what?

• A. The portion of moisture present in the soil at the start of a cycle
• B. The percentage of AWHC that management allows to be used up before an irrigation
• C. The total irrigation water applied per zone
• D. The daily evaporation rate

Answer: (B)

MAD is about how much soil water you allow to be used before you irrigate again. It’s defined as the portion, expressed as a percentage of the soil’s available water-holding capacity, that you permit to be depleted before triggering an irrigation. In practice, after the soil is brought to field capacity, plants can take water from it down toward the wilting point; the MAD value sets the threshold of depletion you are willing to tolerate. This directly guides irrigation scheduling: you irrigation when the usable water that remains drops to that MAD percentage of the available capacity. The idea is to balance saving water with avoiding crop stress.

The other options don’t describe this threshold. It’s not the initial moisture at the start of a cycle, nor the total irrigation depth applied, nor the daily evaporation rate.