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    Author(s): M. R. Haferkamp; P. O. Currie
    Date: 1973
    Source: Agronomy Journal. 65(3): 511-512.
    Publication Series: Scientific Journal (JRNL)
    Station: Rocky Mountain Research Station
    PDF: Download Publication  (148.0 KB)


    Pulling of plants by grazing animals has been a common problem on ‘Sherman’ big bluegrass (Poa ampla Merr.) pastures in Colorado. Fertilizers were applied to individual plants in a greenhouse study to evaluate their influence on plant resistance to pullup. The fertilizer treatments were 56 kg/ha N, 56 kg/ha P, or 56 kg/ha of each element as an N+P combination. Fertilizer treatments were applied to vernalized and nonvernalized plants grown in two soils. Tensions required for pullup in the greenhouse were correlated with total root weight (r = .75**) and significantly increased with N fertilization. Plants fertilized with N produced more vegetative and reproductive shoots, tillers, foliage weight, and root system weight and length. Phosphorus fertilization produced a significant increase in vegetative and reproductive shoots, and a significant interaction between N and P was found for root system size and the amount of roots that were pulled from the soil with the plants.

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    Haferkamp, M. R.; Currie, P. O. 1973. Effects of fertilizer on root strength of Sherman big bluegrass (Poa ampla Merr.). Agronomy Journal. 65(3): 511-512.


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    grazing, Sherman big bluegrass, Poa ampla, fertilizer, root strength

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