Sandy Loam 23-31" PZ

Description

This is the reference or diagnostic community for the site. The description is based on early range site descriptions, clipping data, professional consensus of experienced range specialists, and analysis of field work.

The Midgrass Prairie Community (1.1) is the interpretive plant community for the Sandy Loam Prairie Ecological Site. A variety of midgrasses comprised most of the production. The historic plant community was characterized by sideoats grama and little bluestem. Arizona cottontop, plains bristlegrass and vine-mesquite were locally abundant. Tallgrasses occurred occasionally, with sand bluestem the most common. Sand dropseed, three-awns, hairy grama, fall witchgrass, sand dropseed, blue grama and buffalograss were common shortgrasses. Yucca, catclaw acacia, lotebush, sumac, wolfberry, plum and bumelia were infrequent shrubs. Gaura, dotted gayfeather, primrose, western ragweed, trailing ratany, Mexican sagewort, guara, and Engelmann’s daisy were characteristic forbs. The Midgrass Prairie Community produced from 1,800 to 3,600 pounds of herbage annually.

The Mixed-grass Community (1.2) is mixed-grass dominated grassland. Shrubby species are increasing in density. Typically, mesquite, lotebush and pricklypear are early and persistent invaders. Juniper often invades on the western side of the MLRA. The preferred tall and midgrasses are being replaced by the more grazing resistant meadow dropseed, sand dropseed, hooded windmillgrass, silver bluestem, buffalograss, blue grama and threeawns. Most of the historic grammas, bristlegrasses and feathery bluestems persist in this phase. The perennial forbs found in the historic climax are still present, although in lesser amounts. Annual grasses and forbs invade as ground cover increases and more soil is exposed to erosion. The encroaching woody species are generally less than three feet tall and subject to suppression by prescribed burning in combination with proper grazing management. The woody canopy varies between 5 and 15 percent. Annual primary production is reduced, ranging from 1200 to 3000 pounds per acre.

Submodel

Description

The Shortgrass/Mixed-brush Community supports a 15 to 30 percent woody plant canopy with mesquite, lotebush, pricklypear and yucca the most common shrubs. Mesquite generally dominates although juniper can be locally dominant. There is a decline in diversity of the grassland component and an increase in woody species. Annual herbage production is reduced to approximately 1000 to 2800 pounds per acre.

The Mixed-brush/Shortgrass/Annuals Community is a shrubland with mesquite generally dominates, but pricklypear, lotebush, yucca, and catclaw acacia are common. With continued heavy grazing and no brush control, the shrubs can approach 75 percent or more ground cover. Shortgrasses and low seral stage annual and perennial forbs occupy the woody plant interspaces.

Submodel

Description

The Converted Land Community has been cultivated for cropland or pastureland purposes. Small grain or forage sorghum may be cropped. Permanent native and introduce pasture may also be planted. Sometimes the community may be abandoned and let “go back” to native species encroached by woody species.

Submodel