Identify a soil moisture regime relevant to rangelands and explain how it affects grazing management decisions.

• A. Udic
• B. Xeric
• C. Aridic
• D. Aquic

Answer: (C)

Soil moisture regimes describe how much water is available to plants in the soil across the growing season, which directly drives how much forage a rangeland can produce and when that forage will be available. An aridic moisture regime means soils stay dry for a large part of the growing season, with limited moisture available to plants and highly variable, often low forage production.

This dry, moisture-limited condition governs grazing decisions by requiring a conservative approach to stocking. Managers plan for lower carrying capacity, align grazing with brief pulses of growth after rainfall, and build in flexibility to adjust stocking and rotation during drought years. Rest periods and deferred grazing become important to allow forage to recover after dry spells, and species selection may favor drought-tolerant grasses or forbs. Water and grazing access are managed to avoid overgrazing during drought and to exploit any available moisture efficiently.

For contrast, soils with adequate moisture most years (udic) support more consistent forage and may allow more intensive, year-round grazing, while soils with a Mediterranean-type pattern (xeric) have moisture gaps but not as prolonged as aridic. Wet, waterlogged soils (aquic) create completely different constraints for grazing. The aridic regime is the one that most clearly signals the need for cautious, drought-aware grazing management in rangelands.