Document Type

Thesis - Open Access

Award Date

1990

Degree Name

Master of Science (MS)

Department

Agronomy

First Advisor

Gary D. Lemme

Abstract

The Black Hills are a sharp contrast of trees and steep gradients compared to the rolling grassland seas of the Great Plains. Their complex geology has given rise to a mosaic of soils and vegetation. The Limestone Plateau, comprised of Pahasapa and Minnekahta limestone and Minnelusa sandstone, surrounds the central core of metamorphic and granitic rock. A series of uplifts formed the roughly concentric ovals. The extensive beds of Pahasapa Limestone can reach thicknesses of up to 396 meters (Darton and Paige, 1925). Of particular interest to natural resource managers and ranchers is the understory vegetation production on limestone derived soils. Little work has been done in the Black Hills on these soils, yet they have potential for higher forage returns per management dollar spent than other soils in the area (Bennett et al., 1987). Understory vegetation, which consists of grasses, forbs, and shrubs, is of great economic importance. These plants support not only the indigenous herbivores such as deer (Odocoileus virginianus and O. hemionus) and elk (Cervus elaphus), but also a large commercial livestock ranching industry in the Black Hills. According to Hof et al. (1985), “…most management practices effect all resource outputs. This concept of joint resource production is especially important for timber management practices on forested communities.” Of the over 485,830 ha of land in the Black Hills under the auspices of the United States Forest Service, 481,781 ha are leased for grazing. However, only 193,927 ha are suitable for grazing. Dense overstory vegetation, steep slopes, and water availability were cited as the primary limiting factors (USFS, 1983). Harvesting the overstory should alleviate part of the problem. Schmidt (1979) summarized the importance of understory plants to the ecosystem stating that, “…serves both actively and passively to increase wildlife and aesthetic values, and to protect the basic soil resource.” Since the passage of the National Forest Management Act (1976) and the Forest and Rangeland Renewable Resources Act (1974), the Forest Service is required to employ a multiple-use management scheme. Foresters must document the impacts that a silvicultural practice has on recreation, wildlife, watershed, and grazing resources. Understory vegetation models generated for the limestone plateau would be an asset for management planning as well as an indicator of the extent a silvicultural treatment might affect the other resources, especially range and wildlife. In order to fill the void in the information concerning understory vegetation production on limestone soils, the Soil Conservation Service, the Forest Service, and South Dakota State University established a cooperative agreement. The objectives of this study were: 1) To quantify the annual understory vegetation production on five soil series found in the limestone areas of the Black Hills. 2) To develop statistical models for predicting understory vegetation production relative to canopy cover for said soils. 3) To characterize the physical, chemical, and morphological properties of the major soils on the Limestone Plateau. 4) To make a preliminary assessment of forage quality of understory plants.

Library of Congress Subject Headings

Forage plants -- Black Hills (S.D. and Wyo.) -- Soils
Soils -- Nitrogen content

Format

application/pdf

Number of Pages

125

Publisher

South Dakota State University

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