Browsing Journal of Range Management, Volume 40, Number 6 (November 1987) by Subjects
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Germination of downy brome from southern Kansas, central Oklahoma, and north TexasMature downy brome (Bromus tectorum L.) seeds collected in Texas, Oklahoma, and Kansas in mid-June did not germinate at summer temperatures even when supplied with adequate moisture. The after-ripening of seeds for 3 months produces germination of 50% or more in most populations, as does subjecting fresh seeds to November temperature regimes. These results are similar to those reported for downy brome seeds from eastern Washington, central Idaho, and central California in which fresh seeds are dormant. They differ from those reported for seeds from Montana, northern California, northern and western Nevada, southern Idaho, and northern Utah in which fresh seeds germinate at high percentages. Dormancy of fresh seeds from the Southern Great Plains delays downy brome germination until the fall season at which time rainfall and other climatic conditions are more favorable for its survival.
Selective control of annual bromes in perennial grass standsThree soil-active herbicides: atrazine [6-chloro-N-ethyl]-N1-(1-methyethyl)-1,3,5-triazine-2,4-diamine]; propham (1-methylethyl phenyl carbamate); and pronamide [3,5-dichloro(N-1,1-dimethyl-2-propynyl)benzamide] were applied in the fall, postemergence to annual bromegrasses at 2 rates. These herbicides were evaluated for their efficacy in selective control of cheatgrass (Bromus tectorum L.) and Japanese brome (Bromus japonicus Thunb.) in perennial stands of crested wheatgrass (Agropyron cristatum [L.] Gaertn.), pubescent wheatgrass (Thinopyrum intermedium Host), Russian wildrye (Psathrostachys juncea [Fisch.] Nevski), and western wheatgrass (Pascopyrum smithii (Rydb.) Löve) and blue grama (Bouteloua gracilis) [H.B.K.] Lag. Ex Griffiths. Yields of annual bromegrasses and perennial grasses and crude protein (CP), phosphorus and total nonstructural carbohydrate (TNC) content of perennial grasses were measured 2 consecutive years after the single herbicide application. Yields of annual bromegrasses from the 3 herbicide treatments averaged 91 and 47% less than those of the control the first and second year posttreatment, respectively. Pronamide provided substantially better control the second year posttreatment than the other 2 herbicides. Yields of perennial grasses in the majority of the herbicide treatment-study site combinations were significantly increased the first year posttreatment (P<0.10). Crude protein of perennial grasses was increased in the atrazine treatment. Atrazine at 0.6 kg/ha was the most cost-effective herbicide for decreasing competition of annual bromegrasses and increasing yield of perennial grasses.