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University of Arizona (1977)

Predicting semidesert range perennial grass production from recent precipitation and grazing levels

Rivers, William James

Titre : Predicting semidesert range perennial grass production from recent precipitation and grazing levels

Auteur : Rivers, William James

Université de soutenance : University of Arizona

Grade : Master of Science (MS) 1977

Résumé
Perennial grass production on the Santa Rita Experimental Range about 4o miles south of Tucson is studied for responses to recent precipitation, use, key species, and range condition. Responses were evaluated by multiple linear regression analysis, cOrrelation coefficient analyses, and path coefficient analyses. Data were made available by the U. S. Dept. Agr. Forest Service. Observations were recorded annually from 1957 to 1966 for use, precipitation, and perennial grass production on 20 transects in each of four pastures. Perennial grass and shrub intercepts were read from the same transects for the period 1956-1966, excluding 1960. Range condition ratings were made on each of the transects in 1966. Perennial grass production was shown to be dependent on the product of current August X previous June-September precipitation. Use levels generally had weak negative effects on production. Range condition was found to be correlated with 10-year mean use. Range condition was not closely correlated with perennial grass production. Forage cover and percent invaders, decreasers, and increasers were the major determinants of range condition rating. These factors were not strongly correlated with perennial grass production.

Mots clés : Hydrology. ; Rangelands — Research — Arizona. ; Grasslands — Arizona. ; Grasses — Arizona.

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Page publiée le 6 mai 2016, mise à jour le 16 décembre 2017