Figure 9— Old orphaned spoils naturally revegetated during the past 35 years at the Indian Head mine in North Dakota. The 

 steeper, clay-rich slopes of this spoil (right background) are sparsely vegetated because of their high sodium content. 

 This area has abundant wildlife, including deer. October 1978. 



and the yield (biomass) potentials, and although 

 wind may bury seeds and plants, abrade them, or 

 expose them to dessication, the amount of 

 moisture available to plants is the governing fac- 

 tor in successful revegetation. Because of the 

 high evaporation rates in the w/estern coal areas, 

 the availability of soil moisture is the critical 

 element in seed germination, early growth of 

 plants, establishment of transplants, and contin- 

 ued growth. A detailed statistical examination of 

 western coal reclamation potentials using multi- 

 ple regression analysis confirmed that the 

 amount of precipitation and the length of the 

 growing season are highly significant factors 

 (Packer and others, 1981). 



Although there is no realistic way to modify 

 adverse effects of a microclimate except by add- 

 ing moisture through irrigation, a variety of pro- 

 cedures have been used to minimize unfavorable 

 conditions at the microclimatic level. Ground 

 temperatures that affect seed germination and 

 growth can be modified by using mulches or 



temporary cover crops, by altering slope aspect, 

 or by establishing other shading devices such as 

 rows of trees and shrubs, rock piles, or snow 

 fences. These procedures also reduce wind and 

 water erosion and conserve soil moisture. More 

 passive approaches can also be taken. For ex- 

 ample, seed that first needs a cold period to ger- 

 minate can be sown in the fall in accordance 

 with normal seasonal temperature changes. 



SOIL MOISTURE 



Ensuring adequate soil moisture for plants 

 has been approached in several ways, not only 

 to enhance seed germination and early seedling 

 survival, but also to provide deeper, continued 

 sources of moisture as plants mature. Two 

 studies (Wyatt and others, 1980; Schumacher 

 and others, 1977, p. 16) have indicated that most 

 roots are in the upper 5 to 6 feet of mine spoils. 



24 



