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Accueil du site → Master → Etats Unis → 1986 → EFFECT OF CLIPPING ON PHOTOSYNTHESIS, RESPIRATION AND PRODUCTION OF ERAGROSTIS LEHMANNIANA NEES AND DIGITARIA CALIFORNICA (BENTH.) HENR (ABOVE GROUND BIOMASS, ARIZONA, ROOT PRODUCTION)

University of Arizona (1986)

EFFECT OF CLIPPING ON PHOTOSYNTHESIS, RESPIRATION AND PRODUCTION OF ERAGROSTIS LEHMANNIANA NEES AND DIGITARIA CALIFORNICA (BENTH.) HENR (ABOVE GROUND BIOMASS, ARIZONA, ROOT PRODUCTION)

Giner-Mendoza, Mateo

Titre : EFFECT OF CLIPPING ON PHOTOSYNTHESIS, RESPIRATION AND PRODUCTION OF ERAGROSTIS LEHMANNIANA NEES AND DIGITARIA CALIFORNICA (BENTH.) HENR (ABOVE GROUND BIOMASS, ARIZONA, ROOT PRODUCTION)

Auteur : Giner-Mendoza, Mateo

Université de soutenance : University of Arizona

Grade : Master of Science (MS) 1986

Résumé
Arizona cottontop [Digitaria californica (Benth.) Henr.] has been replaced by Lehmann lovegrass (Eragrostis lehmanniana Nees.) on Southeastern Arizona rangelands. This research was conducted to investigate the effects of defoliation on their physiological and morphological characteristics. Plants were defoliated by clipping at a 5 cm height and measurements made every 14 days. Clipping did not affect apparent photosynthesis or dark respiration during the 56-day study, however, defoliation reduced above ground biomass and the nitrogen and phosphorous content in both species. Root biomass of clipped Arizona cottontop and Lehmann lovegrass declined 59 and 28%, respectively. Nitrogen and phosphorous concentrations in Arizona cottontop roots declined 42 and 61%, and 32 and 27% in Lehmann lovegrass, respectively. The small decline in Lehmann lovegrass root production and the major change in Arizona cottontop root biomass after defoliation may partially explain why Lehmann lovegrass has been replacing Arizona cottontop.

Mots clés : Range plants — Arizona.

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