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= 7.a <br />s , = 1.543 <br />Based on these values, the calculated t-value, 6.12 was greater than the tabulated t-value for <br />alpha error probability of 0.10 at 22 degrees of freedom and the null hypothesis was rejected. <br />The conclusion was that the Pre-1986 Reclamation Area is less than 90% of the approved <br />standard. <br />Total Annual Production <br />Total annual production for the areas sampled in 1999 is summarized in Table 17, represented <br />graphically in Fig. 2, and is detailed in each of the production tables (See 1999 Production Data <br />tables in Appendix 1). Reclamation at the Kerr Mine is deemed successful for biomass <br />production when total annual biomass production in the reclamation block exceed 90% of <br />acreage weighted reference area standard. Details regarding weighted reference area are <br />included in the section, "Statistical Methods- Reclamation Area Success Standards". The <br />calculated success standards and area means for each of the reclaimed areas are included in the <br />following table: <br />Total Annual Biomass Production (gms/0.5 sq.m.) <br />Pre-1986 Rec. 1995 Rec. 1996 Rec. <br />Area Mean 40.9 74.0 52.6 <br />Production Success Standard 30.7 28.8 31.3 <br />Area means in all reclaimed areas exceeded the production success standard. It was concluded <br />that all reclamation units were successful for this parameter. <br />Stocking Rate and Utilization <br />The usefulness of reclaimed area production can initially be assessed by determining the proper <br />livestock stocking rates based solely on measured annual production and desired levels of <br />utilization. Secondary assessments of correct livestock stocking rates also include species <br />composition, distribution of water resources, terrain, and wildlife usage. A range of <br />recommended utilization rates based solely on annual production exist for the Kerr Mine. First, a <br />30-40 percent utilization rate has been found to maintain forage production on sagebrush <br />grassland communities that receive 8 to 12 inches of annual precipitation (Holechek et al, 1989). <br />Second, fifty percent utilization or "take half, and leave half" is a rule-of-thumb value commonly <br />used to estimate proper stocking rate on western rangelands. Each recommended utilization rate <br />and the subsequent stocking rate are summarized as follows: <br /> Stocking Ra[e (AUM1/Acre <br />at Three Levels of Utilization <br />Reclaimed Area Hetbaaous Production <br />Oven-tlry Ib./acre 308 Utilieatim 408 Utilisation 508 Uiliration <br />Pre-1986 Rec. 729.81 0.27 0.36 0.45 <br />1995 Rec. 1320.40 0.49 0.65 0.82 <br />1996 Rec. 938.60 0.35 0.46 0.58 <br />Alkali-Sa a ReF. Area 563.90 0.21 0.28 0.35 <br />Sa a-Grass Ref. Area 854.72 0.32 0.42 ~ 0.53 <br />Sa aGravel Ref. Area 529.96 0.20 0.26 0.33 <br />14 <br />