CONDITIONS. 

 MATERIALS, 



FUMIGATION METHODS 



Soils of the Coeur d'Alene nursery, where most of the trials were conducted, are 

 well-drained sandy loam underlain by water-sorted sands and gravels. Surface-soil pH 

 averages 6.2; organic matter content ranges from 2.6 to 4.2 percent. The site is 

 located at an elevation of 2,500 feet and was previously forested with ponderosa pine 

 {Finns ponderosa Laws . ) ^ 



Savenac nursery soils involved in fumigation studies are well-drained loams and 

 silt loams derived from stream and glacial outwash deposits. The original vegetation 

 of this site was a mixed conifer type, Douglas-fir [Pseudotsuga menziesii var. glauca 

 (Beissn.) Franco], grand fir [Abies grandis (Dougl.) Lindl.], western ^larch {Larix 

 oooidentalis Nutt,), and lodgepole pine {Finns aontorta Dougl.). Surface soil pH 

 averages 6.6 with an organic matter content of about 2 percent.^ 



After some promising trials of soil fumigation at both Savenac and Coeur d'Alene 

 in 1960, serious experimentation was started at the Coeur d'Alene nursery in the fall 

 of 1961. By 1962, it was obvious that a more complete evaluation was needed. Conse- 

 quently, in 1963 a major fumigation test was initiated. This included both spring and 

 fall fumigation, a number of additional promising fumigants , varied rates of application 

 for some, and applications at both the Coeur d'Alene and Savenac nurseries (table 1). 

 Soils treated with each fumigant at these two nurseries were broadcast sown with 

 stratified, but otherwise untreated, western white pine {Finns monticola Dougl.), 

 Douglas-fir, ponderosa pine, and Engelmann spruce {Picea engelmannii Parry). 



Since the 1963 trials, all of the operational fumigation areas have been closely 

 observed, usually with some unfumigated check areas incorporated into the program, to 

 provide continued monitoring of fumigation effectiveness. Additional species have 

 been grown in fumigated soils including grand fir, western larch, and lodgepole pine. 



2r. C. McConnell and M. G. Klages. Forest nursery soils of northern Idaho and 

 western Montana. Mont. Agr. Exp. Sta. Bull. 63, 33 p., illus. 1969. 



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