Physiographic features

This site occurs intermittently on nearly level to sloping uplands. This site commonly occurs on the leeward side of playa lakes and may in effect be a large low dune formed by deposition of wind blown material from the lake floor. Slopes range from 0 to 9 percent. Elevation is from 4,800 to 5,800 feet above sea level. The exposure is generally to the south and west but may vary and is not significant.

Table 2. Representative physiographic features

Climatic features

The climate of this area can be classified as “semi-arid continental”.

Precipitation averages from about 15 to 16 inches annually with approximately 75 percent of this yearly moisture falling during the period of May through October. Most summer rainfall is associated with usually brief afternoon and evening thundershowers, which occasionally produce heavy rain over a small area, and sometimes bring a little hail. Winters are generally dry, with only one or two days a month when as much as one-tenth inch of moisture falls. However, winter average 20 inches of snow, although most snowfalls are light with an occasional storm producing up to six inches. Following these storms, snow may lie on the ground for several days and occasionally moderate to strong winds accompanying these storms result in blizzard conditions and heavy drifting. Although the precipitation patterns favor the production of warm-season plants, sufficient moisture is received in the late winter and the spring to support cool-season plants. Approximately 25 percent of the annual precipitation is received during April and May. May is generally the wettest month followed by July and then August.

Temperatures show the seasonal changes and large annual and diurnal ranges characteristic of such a climate. Summers are generally mild. The high daily temperature reading exceed 90 degrees F about one-third of the time, and readings of 100 degrees F occur about once a year. Rapid cooling after sundown results in minimum temperatures below 60 degrees F on most nights, even in midsummer. Winter shade temperatures usually rise to the mid-40’s and an average of only 15 days fail to see temperatures rise above the freezing mark most of the time from early November through March; below zero readings occur on an average of only three times a year.

The freeze-free season ranges from 168 days to 171 days between April 28th to October 16th. Both temperatures and annual precipitation favor warm-season plants. About 40 percent of the annual precipitation is received during the season where temperatures will benefit cool-season plants and only 10 percent falls during the dormant season.

While open to winter invasions of arctic air over the Great Plains, this area is far enough south and west to miss many of these outbreaks. Mountains to the north and west intercept mush of the precipitation from the Pacific northwest storms coming through this area during the winter. An average hourly wind velocity for the year is 15 miles per hour. Somewhat higher winds prevail during the spring months, but velocities exceeding 24 mile per hour are experienced only 10 percent of the usual year. Stronger winds blow chiefly from a westerly or southwesterly direction during the spring. Relative humidity is moderately low.

Climate data was obtained from http://www.wrcc.sage.dri.edu/summary/climsmnm.html web site using 50% probability for freeze-free and frost-free seasons using 28.5 degrees F and 32.5 degrees F respectively.

Table 3. Representative climatic features

Influencing water features

This site is not influenced by water from a wetland or stream.

Soil features

The soils of this site are deep, well drained and are calcareous on the surface and throughout their profile. The surface layer is loam, sandy loam or fine sandy loam 6 to 8 inches thick. The subsurface is clay loam or loam. The permeability is moderate to moderately rapid. The available water-holding capacity is moderate. Effective rooting depth is 60 inches with some limitations for depth below 20 inches due to dense lime. The calcium content of these soils has a direct effect on the kinds and amounts of vegetation produced.

Table 4. Representative soil features

Hydrological functions

The runoff curve numbers are determined by field investigations using hydrologic cover conditions and hydrologic soil groups.
Soil Series----Hydrologic Group
Bankark---------A
Karde-----------B
Kim-------------B
Spurlock--------B
Valent----------A

Recreational uses

This site provides very limited recreation potential due to the windblown material, lack of live water and shade. It provides poor hiking, camping and picnicking.

Wood products

This site has not significant potential wood production.

Other products

Grazing:
This site can be grazed any season of the year by all classes of livestock. Approximately 90 percent of the total annual production is from species that furnish forage for grazing animals. There is a large variety of grasses that furnish good nutrition for livestock during most seasons of the year. Protein supplement is normally needed only during the late winter months. Continuous grazing yearlong or grazing continually during the period from April to October will cause the plant community to deteriorate. Species such as sideoats grama, blue grama, western wheatgrass and winterfat will decrease and are replaced by alkali sacaton, inland saltgrass, broom snakeweed and annual forbs. The decline in the plant community is usually accompanied by loss of plant cover causing a severe soil-blowing problem. Generally, this site is among the first to be overgrazed due to the proximity of the site to the intermittent playas where many pit tanks are constructed making water available longer. A system of deferred grazing is needed to maintain or improve a healthy well-balanced plant community. Deferment during different seasons of the year benefits different plants. Winter deferment benefits winterfat and fourwing saltbush. Spring (April – June) rest benefits forbs and cool-season grasses such as western wheatgrass, New Mexico feathergrass and bottlebrush squirreltail. Summer (July – September) rest benefits warm-season plants such as sideoats grama, blue grama, and little bluestem. Summer rest allows the cool-season species to complete their growth cycle. Fall rest allows warm-season plants to complete their growth cycle.

Other information

Guide to Suggested Initial Stocking Rate Acres per Animal Unit Month
Similarity Index-----Ac/AUM
100 - 76-------------2.4 – 4.0
75 – 51--------------3.3 – 4.9
50 – 26--------------4.2 – 6.5
25 – 0---------------6.5+

Type locality

Contributors

Christine Bishop
Don Sylvester
John E. Tunberg