Dry Shallow Loam

Description

If ecological retrogression is cattle-induced, Indian ricegrass, mountain muhly, and Arizona fescue decline relatively fast. Blue grama, needle and thread, bottlebrush squirreltail, and western wheatgrass initially increase, but with continued retrogression they also decline. With advanced retrogression, slimstem muhly and poor vigor blue grama become the dominant grasses. Forbs such as sidebells penstemon will decrease with heavy over grazing. Other forbs, such as hairy goldaster, germander penstemon, matted nailwort, and Nuttall Kentrophyta milkvetch will increase.

Shrubs such as spineless (gray) horsebrush, small (yellow) rabbitbrush, broom snakeweed, pingue hymenoxys, fringed sage, and small soapweed tend to increase into the available niches left by disappearing grass plants.

Basal area (the area of ground surface covered by the perennial vegetation measured one inch above the soil) is approximately 15 percent.

Annual production
If the range is in excellent condition, the approximate total annual production (air-dry) is:
Favorable years 600 pounds/acre
Normal years 450 pounds/acre
Unfavorable years 300 pounds/acre
Of this production 15 to 20 percent will likely be unpalatable or out of reach of grazing animals.

Submodel