Figure 11.— Second season of revegetation by seeding at the McKinley mine in New Mexico. The area was seeded with west- 

 ern and crested wheatgrasses (light clumps) and planted with seedlings of fourwing saltbush (dark clumps). Some fourwing 

 saltbush has reseeded on this slope. Thin topsoil was used; some undisturbed areas at the mine site have little if any soil to 

 be saved for topsoiling. This land will be returned to use as range. Note the spacing of the saltbush in this planting, which 

 was made without irrigation; the plants developed in adjustment to natural moisture availability. November 1978. 



Irrigation allows planting over a greater time 

 period and assures the highest percentage of 

 seed germination and initial plant survival, irri- 

 gation was observed as an operating procedure 

 only at the Navajo and San Juan mines of New 

 Mexico where powerplant cooling water is read- 

 ily available. It has also been experimentally 

 used at other mine reclamation sites (Ries and 

 Day, 1978, p. 509-512). Sprinkler irrigation has 

 proved to be the most satisfactory method under 

 field conditions (Aldon and others, 1976). Irriga- 

 tion must be scheduled, however, so that when 

 it is discontinued some plants will survive with- 

 out it (Curry, 1975, p. 36-37). It has been ob- 

 served that on some irrigated mine spoils in New 

 Mexico, vegetation thinned out significantly 

 after irrigation was stopped. 



Droughts occur periodically in the western 

 coalfields. A plant species or plant community 

 that is only marginally established is more sen- 

 sitive to the stress of overgrazing, insect attack, 

 or drought. Although the first two can be con- 

 trolled, the climate cannot. Dry years have had 

 disasterous effects on new plantings, but the 

 effects of sustained drought on established 

 mine reclamation plantings have not been docu- 

 mented. There have been no sustained long 

 droughts in the western coal region since the 

 late 1930's (Curry, 1975, p. 40). Following the 

 droughts of that period, however, large changes 

 in plant communities, both native and planted, 

 did occur in a variety of physical situations 



26 



