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r . chosen area was the most uniform in terms of plant develop- ment of reseeded areas in Pit No. 6 large enough to be divided into pastures. The chosen pasture area was subdivided into six pastures ranging from 4.7 to 12.2 acres to accommodate two grazing treatments with three replications of each. The treatments are moderate grazing (503a utilization) and no grazing. The long-term objective of the study (objective 2) is to graze native range in conjunction with the reseeded spoil in a com- plementary pasture grazing system. A native range pasture will be selected and baseline plant data will be collected in the coming field season. - Two periods ofgrazing in the designated pastures will be carried out during the firs[ phase of the study. The first will be. from April.to mid-June, The second will begin in August and last until proper utilization of the forage has been reached. During the coming field season the livestock will be held on reserve pasturage during midsummer. In following years livestock will be taken to native range during the dry part of the summer. These grazing periods will utilize reseeded spoil early in [he spring when native range is no[ ready, native range in the summer when reseeded spoil is less palatable and reseeded spoil again in the fall when "greenup" occurs on the spoils seedings. Pastures I, 2 and 4 were randomly chosen for grazing during the lust few years of study. Pastures 3, S and 6 will serve as controls (no grazing) until enough data are collected to determine the initial effects of grazing on vegetation, to determine the proper stocking rate, and to determine the probable cattle weight gains. This project will require long-term support, possibly five or more years When sufficient information has been cdlected on both the reseeded pastures and native range, the study may be expanded in scope to evaluate a yearlong manage- mentsystem integrating both native range and reseeded mine spoil. Establishment of plant communities on newly mined areas which differ greatly from those presently being studied may require adifferent research approach. The experimental approach to the present study, as well as to future studies, will be geared toward proper range management, the key to successful and sustained reclamation. Late Summer 1975 Grazing _ _ Facilities for the grazing of pastures on reseeded mine spoil were completed by mid-August, 1975, and all baseline data (vegetation and soil) were collected by Aug. 21, 1975. Water tanks of 700 gallon capacity were installed and filled from a trailer drawn tank since there was no permanent water in any of the pastures. Twenty-three head of Hereford cattle (cows, calves and yearlings) were selected and put on the three designated pastures on Aug. 3, 1975, in proportion to the amount of forage available. Grazing of the study site continued until Nov. 15, 1975, when the cattle were removed and taken to winter pasture. The purpose of this first grazing period was to utilize the abundant forage produced during the 1975 growing season. Cattle weights were not monitored because facilities were not available. Weigh[ measurements, however, will be taken in each of succeeding grazing periods. Some Preliminary Results Forage production and carrying capacity The grazing area on reseeded spoil supports a varied flora (Tables I and 2) although many species constitute only minor or trace percentages of the total plant production. Table 1. Standing vegetative biomasst (Ibs/A) at the experimental grazing pastures of Colstrip on July 24, 1975. Species p(artr groupings 2 3 Pasture number 4 S 6 Avg. Smooth bromegrass ....... ............... 242 387 166 242 277 286 267 Crested wheatgrass ........ ............... 784 1401 950 1214 901 744 999 Tall wheatgrass .......... ............... 240 248 132 241 205 177 207 Other perennial grasses ..... ............... 176 41 53 55 43 26 66 Annual grasses ........... ............... 36 18 0 0 70 9 22 Legumes and (orbs= ....... ............... 589 424 269 325 284 763 442 Shrubs ................ ............... 0 0 4 2 12 2 3 Total standing biomass ..... ...............2066 2518 1574 2079 1792 2008 2006 This includes only the current year's (ive growth on the date of measurement 1Principally ye!(ow sweetc(over.