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Evaluation Of The Early Establishment Phase Of Agropyron Desertorum, Medicago Sativa And Atriplex Canescens In Monocultures And Mixtures, Oscar Luis Prado Escobar

All Graduate Theses and Dissertations, Spring 1920 to Summer 2023

This study evaluated the early establishment phase of various monocultures and mixed species plantings of Agropyron desertorum (AGDE), Medicago sativa (MESA), and Atriplex canescens (ATCA). The study was conducted under both greenhouse and field conditions. In the greenhouse, the experimental design was a split-plot, randomized-block design in time, using transplanted seedlings. The treatments were exposed to three water levels to determine species response to varying moisture availability. Plastic pots of 15.4 cm (diameter) by 17.9 cm (depth) were filled with 2,800 g of sandy-loam soil and brought to field capacity. The pots were weighted twice weekly and the water lost …

Rhizosphere N2 Fixation In A Forest Ecosystem In Situ Assays And Evaluation Of The Acetylene Reduction Technique, Inger Börjesson

All Graduate Theses and Dissertations, Spring 1920 to Summer 2023

In situ assays of N₂ fixation activity, using the acetylene reduction technique, were performed in four successional stages of a Northern Wasatch Mountain subalpine forest ecosystem, elevation 2,800 m. Emphasis was made on rhizosphere fixation in association with Antennaria microphylla and Achillea millefolium. The vegetation period was approximately 100 days.

Assays were performed in Saran bags. A defined amount of propane was injected at initiation of the assay and acetylene was generated from CaC₂. Samples were analyzed for ethylene and propane. Data were evaluated assuming that the ethylene production was directly proportional to the increase in …