Browsing by Author "Perry, D.A."

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    Nitrogen-Fixing Plants for Silviculture: Some Genecological Considerations
    (1979) Perry, D.A.; Wheeler, C.T.; Helgerson, O.T.
    Nitrogen fixation as a silvicultural tool will require symbioses adapted to the relatively harsh temperate forest environment. Ability to survive and fix nitrogen in shade, cold soils, and under water stress are characteristics that must be selected. Research indicates a great deal of genetic diversity among legumes and Rhizobia strains in response to some environmental factors such as temperature, while other potentially important influences have been studied little. Virtually no studies have been done in genotype-environment interaction among nonleguminous symbioses. The small amount of work available suggests that legumes may fix N at higher rates in shade than nonlegumes, although no experiments have specifically tested this question. Legume N-fixation may also be greater in cold soils than that of nonlegumes. Many legumes and nonlegumes grow in droughty conditions, suggesting that searches for drought-adapted species and strains may be worthwhile.
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    Seedling Growth And Mycorrhizal Formation In Clearcut And Adjacent, Undisturbed Soils In Montana: A Greenhouse Bioassay
    (1982) Perry, D.A.; Meyer, M.M.; Egeland, D.; Rose, S.L.; Pilz, D.
    In a series of greenhouse bioassays, tree seedling growth and root-tip development were compared among soils from two areas that had been clearcut and site prepared 16 years earlier and adjacent, undisturbed forest. Seedlings grown in soil from logged areas were shorter and had fewer root tips than those grown in undisturbed forest soil; however, effects on seedling weights were not consistent among species or experimental series. Fertilizing with nitrogen eliminated size differences due to soil source. In Douglas-fir [Pseudotsuga menziesii (Mirb.) Franco], the only species tested in sterilized soils, sterilization of logged soils resulted in increased seedling size and root-tip formation, whereas sterilization of unlogged soils had either no or a negative effect.