Clipping and long-term grazing effects on biomass and carbohydrate reserves of Indian ricegrass
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Authors: A. B. Orodho, and M. J. Trlica
Date: 1990
Journal: Journal of Range Management
Volume: 43
Number: 1
Pages: 52-57
Summary of Methods: Long-term heavy grazing had little effect on root and crown biomass of Indian ricegrass (Oryzopsis hymenoides), nor did it significantly affect the total nonstructural carbohydrate (TNC) reserve levels or the seasonal cycle of reserves in this grass. Orodho and Trlica conclude that 50 years of protection from livestock use had not resulted in ecotypic differentiation in Indian ricegrass for these variables. Clipping reduced crown biomass more than root biomass and removal of 90% of aboveground biomass resulted in more than a 50% reduction in crown biomass and reserve carbohydrate pool. In a garden study that compared the native Chaco Canyon strains to two commercial strains of Indian ricegrass ('Nezpar' and 'Paloma'), the Nezpar strain was superior to Paloma and the Chaco Canyon strains in production of crown biomass and TNC reserves at the more mesic garden site. The native strains from the more arid Chaco Canyon were superior to both cultivated strains in root production, and the native strains were little affected by clipping. These results suggest that long-term heavy grazing has not altered the plant morphology and growth of the field strains of Indian ricegrass and that these field strains may be more drought resistant than commercially available cultivars, however, the results of the garden study suggest that the Nezpar cultivar may also be suitable for use in this area.
Article Summary / Main Points: None
Vegetation Types:
MLRA Ecoregions:
Agrovoc Control Words: Riparian zones Rangelands Wildlife
Article Review Type: Refereed
Article Type: Experimental Research
Keywords: indian ricegrass, oryzopsis hymenoides, heavy grazing, ecotypic differentiation, belowground biomass, carbohydrate reserves
Annotation: Plots were located on a hilltop, hill-side, and in a swale on both heavily grazed and protected (ungrazed) pastures in New Mexico. The area had been grazed by cattle, sheep, goats, and horses until the area was fenced off to livestock in 1984. One of the plots at each site was located within a protected area of the National Park while the other was located on the heavily-grazed area managed by the BLM. Plants were clipped one time at anthesis (typically around June 1st) to a 0,30, 60, or 90% removal of photosynthetic tissue-estimated in the field experiment. Plants in the garden experiment (which took place in Colorado) were clipped one time at anthesis to a 90% utilization level.
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