Use of lime to neutralize soil acidity was ' 

 necessary to allow plant establishment. Extensive 

 sampling of a potential reclamation site was needed 

 before the lime requirement could be predicted. 

 Both the average and range in lime requirement 

 should be characterized, and lime rates should be 

 set to improve 85-95 percent of soils to a target 

 pH of 6 to 6.5. 



In soils that were high in copper and zinc, the use 

 of liming alone did not ensure adequate plant 

 performance. Additional soil amendments, such as 

 phosphorus and manure, might be required to further 

 reduce the availability of copper and zinc to 

 plants. 



Plant performance on the test plots was variable. 

 Some plants may have done poorly partly because the 

 first year of the study was hot and dry. However, 

 promising results were obtained with a number of 

 species, including crested wheatgrass, pubescent 

 wheatgrass, basin wildrye, Russian wildrye, altai 

 wildrye, yellow sweetclover, cicer milkvetch, and 

 birdsfoot trefoil. None of the plants sampled 

 appeared to accumulate metal levels that would be 

 toxic to livestock. 



A moldboard plow/ chisel, plow/harrow tillage 

 sequence gave the best results due to better 

 seedbed preparation, better mixing of lime, and 

 reduced competition from existing vegetation. 



The first phase of the hydrogeologic study was completed 

 in 1986 (Osborne et al. 1986) and was discussed earlier in 

 this chapter. The second phase is ongoing and is being 

 conducted by the Montana Bureau of Mines and Geology. The 

 objectives are: 1) to quantify the concentrations of trace 

 elements in selected intervals of soil and unconsolidated 

 deposits underlying the Spangler Ranch agricultural sites 

 and 2) to identify the mechanisms and rates of trace element 

 movement in the unsaturated zone and shallow aquifers on the 

 sites. The study involves laboratory leaching column 

 experiments and field site lysimeter sampling. 



The following observations were made at the conclusion 

 of the first round of leaching column experiments (Wilson et 

 al. 1988): 



• Of the elements tested, arsenic was most mobile in 

 both amended and nonamended soils. 



3-51 



