UBC Theses and Dissertations
Study of some agronomic factors affecting the yield of Medicago sativa L. var. Ladak and Medicago sativa var. Rhizoma. Davis, William Ernest Paul
Two alfalfa varieties differing in root characteristics were studied under the climatic conditions existing at Agassiz, in the Lower Fraser Valley of British Columbia. The soil type of the experimental area was Monroe fine, sandy loam underlain with gravel. A preliminary study of plant densities in old established plots of alfalfa was conducted in the spring of 1951. The main study commenced in the early summer of 1951 and the first harvest data were obtained in 1952. Ladak alfalfa, a tap-rooted variety, and Rhizoma alfalfa, a branched-rooted variety, were grown in separate associations with Hercules orchardgrass and with Parkland bromegrass. Two planting methods, seeding and spaced-planting of seedlings, were compared as methods for obtaining the optimum rate of planting for alfalfa. Comparisons based on yield of dry matter were made between the two alfalfa varieties In relation to their response to the following factors: (a) Density of alfalfa in the association -- (1) Seeded at three rates (2) Spaced-planted at three densities. (b) Cutting managements -- (1) Clipping as continuous pasture (2) Cutting at the hay stage, followed by clipping the aftermath to simulate pasturing (3) Taking two cuts at the hay stage and a third cut at the silage or early hay stage. (c) The grass associate -- (1) Orchardgrass (2) Bromegrass. The findings presented are of the first harvest year of a continuing study. The two alfalfa varieties displayed a similar response to treatments. The tap-rooted variety Ladak produced more dry matter than did the branched-rooted variety Rhizoma. Superiority was not established for one grass over the other as the grass associate. Nearly identical results were obtained between methods of planting. The indications were that spaced-planting with its higher cost was only suitable for basic forage studies. The highest rate of planting gave the greatest yield of dry matter. However, the results are inconclusive as the effect of plant spread has not been determined. The spreading habit of Rhizoma was established for the particular area of the study. Its effect on managements has not been established. The hay cutting management produced the greatest yield of dry matter. The continued study will stress the effect of cutting managements, including interval between cuts, date of last fall cut, and date of first spring cut, on the root reserves and the production of nutrients per acre.
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