Table 5. Effects of wood-chip mulch and fertilizer 



Treatment 



Plants per sq.ft 



1957 



1958 



Percent ground cover 



1957 



1958 



'^Control 



Kood-chip mulch 

 Fertiliser 



s>|ulch and fertilizer 



9.4 

 5.8^ 

 10.6 

 7.4 



10.7 

 12.2 

 8.9 

 9.4 



11.5 

 3.0^ 



10.0 

 5.6^ 



16.3 

 9.6^ 

 12.1 

 11.6 



•Comparison with control significant at 1-percent level. 



EFFECT OF SITE VARIABLES 



Several site properties affected plant density in the 2 years of measurement. 

 Plant density was related positively to aspect. The density of plants per square 

 tfoot increased as the roadljed aspect changed from south to north. 



The amount of shade cast by surrounding trees and topography was related benefi- 

 cially to plant density, but not significantly so. 



Roadbed compaction caused by posttreatment vehicular trips back and forth over the 

 )adbed had latent adverse effect on plant density (see fig. 1). 



SPECIES PERFORMANCE 



Results in terms of seedling establishment for the six species are shown in 

 'table 4. Manchar smooth bromegrass and the two wheat grasses--intermediate and 

 ^Standard crested--produced the greatest number of plants per square foot, almost 71 

 ^percent of the total plant count. Their establishment percentages, based upon number 

 :*f_viable seeds broadcast per square foot, were also the highest, 16 to 22 percent, 

 Icating that of the five perennials tested, these three grasses appeared to be best 

 ted to the growing conditions of the study area. Interestingly, in 1957 smooth 

 :ass and winter rye were more abundant on the cool, northeast aspects than on 

 ithe southwest aspect. The southwest aspect was superior for bulbous bluegrass. By 

 ''^"^^^ ^® ^^'^ practically disappeared from the roadbeds. 



lndi( 

 Sdaptt 

 Ibromegxa 

 ^the ! 

 1958. 



Other adaptability studies conducted in the ponderosa pine zone of the Inter- 

 and Rocky Mountain regions show Manchar smooth bromegrass and the two 

 catgrasses as being well suited. Evanko (2), working in a large ponderosa pine 

 iiung in northeastern Washington, rated the wheat grasses in a superior group and 

 ichar smooth bromegrass in the next-best group. He found timothy unsatisfactory in 

 ^^^Pects , but rated orchardgrass as good as the wheatgrasses . Johnson and Hull 

 lyj reported that intermediate and crested wheatgrass, smooth and meadow bromegrass, 

 tsian wildrye, and big bluegrass out of 82 species tested appeared to be the most 

 generally adapted to central Colorado. 



