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• First cutting hay bales were counted either in the field or from the stacks. Next, an adequate sample of <br />the bales from each field was weighed using a Hanson 93490 portable scale. This scale has a maximum <br />capacity of 200 pounds and is accurate to the nearest pound. A minimum of 30 bales were weighed from <br />each field except for one field which had 21 bales. In that field, 10 bales were weighed. Care was taken <br />to select bales from throughout a field, or in cases where the bales had already been stacked, from many <br />locations in the stack. The hay production in the fields, expressed on a dry weight basis as pounds/acre, <br />was calculated by multiplying the total number of bales counted in a field by the average adjusted bale <br />weight and dividing by the size of the field in acres. Additionally, clipped plots in similar irrigated pastures <br />were used for comparision. <br />Woody Plant Densities - 1999. Woody plant densities were measured in the sagebrush types, dryland <br />pasture reference area, and willow component of the Swale/drainage type using belt transects. All trees <br />and shrubs were included in the counts as outlined in CDMG "Guidelines for Compliance with Land Use <br />and Vegetation Requirements for Coal Mining". A species was counted for density if it was rooted within <br />the belt. For all species except willow stems were traced back to their origin and counted as one plant. <br />For example, a sagebrush plant that had 4 stems emanating from a central point was counted as one <br />plant/stem. A 3 ft. x 100 ft. belt, originating at the randomly-located sample point and extending in a <br />random direction, was used in the sagebrush type and dry land reference area. Arandomly-located 1 <br />• square meter sampling frame was used for stem counts in the willow component of the Swale/drainage. <br />All willow stems emanating from the ground were counted as it was impossible to determine if any one <br />stem belonged to any one plant. Fifteen samples were collected in this manner. <br />Sample Adequacy 1987 and 1999. The following formula was used to determine the adequacy of the <br />quantitative cover, production, and woody density samples in the New Horizon 2 studies: <br />where, <br />Nmin =minimum sample size <br />s =sample standard deviation <br />= two-tailed t-value at the 90 percent confidence interval <br />(alpha = 0.10) with infinite degrees of freedom (t = 1.645) <br />d =desired level of reduction about the sample mean (0.10) <br />x =sample mean <br />• (REVISED B/15/00) 2.04.10 - 21 <br />