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    Author(s): Marshall R. Haferkamp
    Date: 1969
    Source: Fort Collins, CO: Colorado State University. 68 p. Thesis.
    Publication Series: Theses
    Station: Rocky Mountain Research Station
    PDF: Download Publication  (991.0 KB)


    Sherman big bluegrass (Poa ampla Merr.) is a long-lived bunchgrass native to the Pacific Northwest. This species has been seeded in the Rocky Mountains and in some areas has produced greater livestock gains than native range during spring, summer, and late fall. Unfortunately, big bluegrass has an undesirable characteristic that reduces its value and use; plants are frequently pulled up by grazing animals. This occurs because the root system breaks at the crown to 7 to 10 cm below the soil surface. Low soil fertility was suspected as a possible cause of root breakage. To evaluate this factor, 96 vernalized and unvernalized big bluegrass plants were grown in two sets of 24 glass-faced planter boxes, one set containing new soil, and one set containing soil that was stored for a year. Plants received one of four treatments; a check, with no fertilizer, 56 kg/ha elemental N, 56 kg/ha elemental P, or both Nand P at the 56 kg/ha rate. Foliage and roots were measured to establish what effect the fertilizers had on growth, and how breakage of root systems was altered. Pullup tension appeared to be closely correlated with total root weight, and results indicate that fertilizers can be used to reduce root breakage.

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    Haferkamp; Marshall R. 1969. Effect of fertilizer on big bluegrass. Fort Collins, CO: Colorado State University. 68 p. Thesis.


    Sherman big bluegrass, Poa ampla, livestock gains, range management

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