Rapid desiccation of soils witli the onset of the dry season is characteristic of many 

 rangeland sites in southwestern Idaho. Soil moisture, after being recharged in June, dropped 

 to a season minimum of about 2 percent at the 6-inch (15-cm) depth in mid-August (fig. 2). 

 Soil moisture percentages were markedly higher under scalps than under unscalped areas (table 3) . 

 First-year survival trends appear weakly correlated with soil moisture trends. The soil mois- 

 ture recharge in June may have prevented more steeply declining survival curves. 



Table 3. --Average soil moisture content (percent) at three depths (cm) on scalped and unscalped 



areas, 1969^ 



Date 



Treatment 



Depth 



5/1 



5/14 



5/27 



6/18 



7/8 



7/31 



8/20 



9/10 



Scalped 



15 



7.5 



6.4 



5.5 



5.6 



6.8 



3.8 



2.2 



2.7 





30 



7.7 



6.8 



5.9 



5.6 



7.3 



4.4 



3.4 



3.7 





60 



8.0 



8.0 



7 . 1 



5.5 



7.7 



4.6 



4.2 



4.8 



Unscalped 



15 



4.3 



2.8 



-) -7 



4.3 



6.2 



3.2 



1.5 



1.4 





50 



5.8 



3.9 



3.6 



3.2 



7.3 



4.0 



3.0 



3.3 





60 



7.1 



6.0 



5 . 3 



4.0 



6.4 



4.4 



3.6 



3.7 



^Each soil 



moisture value 



is the 



average of 



six samp 



ling sites 



di stributed 



throughout 



the 



planting area. 



Sixtli-year survival differed markedly between species, seed source, and planting method 

 (table 1). Seeded bitterbrush had better survival than bitterbrush transplants. The converse 

 was true for wedgeleaf ceanothus. Overall, seeding treatments averaged 80 percent survival; 

 transplant survival averaged 62 percent. Bitterbrush seeded from local seed sources had a 

 sixth-year survival of 94 percent, higher (P<0.05) than any other treatment. Bitterbrush from 

 local seed sources, whether seeded or transplanted, outjierformed other plants significantly in 

 survival and nonsignif icantly in heiglit growth. Altliough rating standards for shrub plantings 

 are nonexistent, we suspect that few would be dissatisif icd witli sixth-\-ear survival rates from 

 60 to 80 percent (comjKire fig. 3 and 4) . 



7 



