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•t • • 2 The major objectives of the study are: (1) to determine the effect of graz- ing intensity on growth and persistence of the vegetation and on the ability of reclaimed strip-mined soils to remain productive and stable, and (2) to develop methodology for proper evaluation of grazing effects:on newly reclaimed land. The influence of grazing intensity on the forage production and animal per- formance after two season's grazing are presented in this paper. METHODS OF STUDY The study area did not have topsoil replaced as is now required by North Dakota reclamation laws. However, spoils at the study area do not have the moderate to high sodium content found at many other North Dakota mines which limits vegetation establishment (1). _ -~A mixture of smooth bromegrass (Bramus irtermis Leyss.), crested wheatgrass [Agropyran desertorwn (Fisch. Ex Link) Schult.], intermediate wheatgrass [Agropyron intermedtiwn (Host) Beauv.], alfalfa (Medi¢ago sativa L.) and yellow sweetclover (MetiZotus officirtalis Lam.) was seeded at the site in spring 1973. Except for sweet clover, these species predominated at the start of the grazing study consti- tuting 99~ of the live vegetation, as determined by point-frame quadrats. The vegetation was not clipped or grazed before the start of the study. Duplicate pastures of 0. 7, 1.4, and 2.1 ha were fenced on the reclaimed area. Each of the six pastures was stocked with three yearling Hereford steers, producing a stocking rate of 0.24, 0.48, and 0.72 ha/animal for heavy, moderate, and light grazing intensities, respectively. Within each pasture, two 15- X 30-m exclosures provide controls of ungrazed areas throughout the duration of the study. Six 1.2- X 1.5-m cages were placed randomly within each pasture to provide a measure of the current season's growth. All pastures were stocked the same day. All grazing was terminated the same day when we estimated half of the available vegetation for the grazing season had been grazed under the moderate stocking rate. Steers used in the study were weighed daily for 3 days and sorted into uniform weight lots of 3 and assigned to each pasture. After removal from the pastures, they were again weighed daily for 3 days and the average weight from these weigh- ings was used to measure animal performance. Vegetative dry matter production was measured grazing season by clipping six 0.9- X 3.0-m strips exclosures with a sickle bar mower each year. Two were hand clipped at the end of the grazing season production for each pasture in 1977. Each was cut samples were oven-dried at 60C to obtain dry matte RESULTS Vegetative production at the beginning and end of the in the pastures and ungrazed 0.18-m2 areas within each cage to determine the dry matter leaving 4-cm stubble. All yield. Dry matter production for the controls, pasture treatments, and the 1977 season are shown in Table 1.