GENERAL56215 - Laserfiche WebLink

Home Browse Search

~' ~ i • EFFECTS OF GRAZING INTENSITY ON VEGETATION AND ANIMAL PERFORMANCE ON RECLAIMED STRIP-MINED LAND 'L. Hofmann, R. E. Ries, J. F. Power and R. J. Lorenz Research Agronomist, Range Scientist, Soil Scientist and Research Agronomist, respectively Northern Great Plains Research Center, North Central Region Agricultural Research Service, USDA, Mandan, ND 58554 ABSTRACT Reclaimed strip-mined land in North Dakota is somewhat fragile and the effects of grazing these lands are unknown. To study these effects, we stocked duplicate sets of pastures at 0, 0.24, 0.48, and 0.72 ha/yearling steer to obtain control, heavy, moderate, and light grazing intensities, respectively, on land reclaimed under the state's 1969 reclamation law near Center, North Dakota. A mixture of cool-season grasses and legumes was seeded in 1973 and not harvested before begin- ning the study in 1976. During 1976, 3734 kg/ha dry matter was produced on the ungrazed control, and 80, 44, and 32~ of the forage was grazed at the heavy, moder- ate, and light grazing intensities, respectively. The 1976 grazing season was 55 days as compared with 30 days in 1977, which had a much drier spring. In 1977, the heavily grazed pasture had significantly less dry matter than the other treatments when grazing was started. When grazing was stopped, no harvestable forage remained on the heavily grazed pastures. Steers on heavily grazed pastures produced average daily gains of 0.4 kg/head as compared with 0.9 kg/head on the moderately and lightly grazed pastures. Beef production in 1977 equalled 55, 58, and 41 kg/ha for the heavy, moderate, and lightly grazed pastures, respectively. These preliminary data indicated that reclaimed mined land should be suitable for grazing, but addi- tional research is needed to establish good grazing management guidelines for reclaimed land. INTRODUCTION In the Northern Great Plains, most land disturbed by strip-mining for coal, was once productive agricultural land. Therefore, after mining, reclamation practices are aimed at returning land to its full agricultural potential. About SOB of the land proposed for mining in North Dakota is pasture or rangeland, much of which will be revegetated with perennial forage species to provide grazing for the livestock industry. Although most grass and legume species currently used for grazing on unmined lands in the Northern Great Plains have been extensively studied, the effects of grazing these species on reclaimed lands are unknown. To evaluate the effects of grazing intensity on the plant and soil aspects of reclaimed strip-mined land, we initiated a grazing study in spring 1976 on a site located near Center, North Dakota which had been reclaimed under the state of North Dakota's 1969 reclamation law. In spring 1973, the land was reshaped and seeded to a mixture of six perennial grass and legume species by the Baukol-Noonan Mining Company. The site was released from bond by the North Dakota Public Ser- vice Commission and returned to the original owners in spring 1976, when the Agricultural Research Service leased part of the area for this study.