Influence of Crusting Soil Surfaces on Emergence and Establishment of Crested Wheatgrass, Squirreltail, Thurber Needlegrass, and Fourwing Saltbush

Crusting soil surfaces with vesicular pores occur in arid and semiarid regions of the world where herbaceous vegetation is sparse. Morphological properties of crusting surfaces can impair seedling emergence and plant establishment. This study evaluated site preparation and seeding methods and species useful for encouraging successful stand establishment in such soils. Plowing to prepare a seedbed reduced seedling emergence on some soils but increased plant establishment on all soils. More seedlings emerged and established on non-crusting coppice soil beneath shrubs than on crusting interspace soil between shrubs. Crested wheatgrass was the most successful species followed closely by squirreltail and distantly by Thurber needlegrass and fourwing saltbush. Fourwing saltbush seedlings became established and grew well in some treatments. Seedling emergence and establishment were highest with the deep-furrow seeding technique on the non-crusting coppice soil. The standard-drill technique gave the best stand on the site with the largest surface cover of bare, crusting interspace soil. Soils with crusting surfaces occur in many arid and semiarid regions of the world. Various features of these soils in the western United States were described by Hugie and Passey (1964) and Schlatterer (1968). In the Great Basin these soils commonly are associated with northern-desert shrub and salt-desert shrub plant communities that have sparse herbaceous vegetation. In northern Nevada, such soils are found in the Humboldt Loess Belt, an &million-ha area of shallow, windblown silt and very fine sand deposition. These soils are on gently sloping fan piedmonts and nearly level alluvial flats. They include both typic and xerollic Durargids, Haplargids, Nadurargids, and Natrargids and have moderately fine and fine textured B2t horizons. These soils generally are crusted between shrubs (interspace soil) and are noncrusted beneath the shrubs (coppice soil) (Stuart et al. 1971, Blackburn 1975). The microtopographic positions, surface physiognomy, and morphological characteristics of the A horizon were presented by Eckert et al. in 1978. These surficial features are not mapped or measured even in detailed soil surveys, but must be determined on a site by site basis. The crusting interspace surfaces commonly are sandy loam, loam, or silt texture high in very fine sand or silt, with low organic matter content, are massive, and have vesicular pores. These factors contribute to the unfavorable behavThe authors are presently assistant professor of watershed management, Department of Animal and Range Sciences and Range Improvement Task Force, New Mexico State University, Las Cruces, 88003; range scientist, U.S. Dep. Agr., Agr. Res. Serv. Renewable Resources Center, University of Nevada, 920 Valley Road, Reno, 89512; professor of watershed management, Range Science Department, Texas A&M University, College Station, 77843; and professor of Soil Science, Plant, Soil. and Water Science Division, University of Nevada, Reno, 89512. This study was a cooperative investigation among U.S. Dep. Agr., Agr. Res. Serv., Bureau of Land Management, and Agr. Exp. Sta., Univ. of Nevada, Reno. Journal Series No. 483. Plant nomenclature follows Plummer et al. (1977). Manuscript received August 20, I98 I. 282 ior of this surface: unstable and slakes when saturated, dries to a crust that can reduce seedling emergence (Wood et al. 1978), and has a low water infiltration rate and high sediment production (Blackburn 1975). Wood et al. (1978) stated that rangelands with these kinds of soils have higher potential productivity than their present fair to poor condition suggests. These authors postulated that theareas of crusting interspace soil increase with overgrazing, loss of herbaceous cover, and lowered range condition at the expense of noncrusting coppice surface soil. They also stated that revegetation of these problem soils through grazing management alone would be difficult, if not impossible, in a reasonable time and that artificial seeding methods are required to establish forage species. Therefore, we evaluated seedling emergence and plant establishment of various species seeded by different techniques on soils with crusting and non-crusting surfaces.