Factors Affecting Establishment, Survival, and Production of Birdsfoot Trefoil (Lotus Corniculatus L.) and Alfalfa (Medicago Sativa L.) PDF Download

Author: Clee Scott Cooper
Publisher:
ISBN:
Category : Alfalfa
Languages : en
Pages : 202

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Book Description
Field, greenhouse, growth chamber and laboratory experiments evaluated factors affecting establishment, survival and production of birdsfoot trefoil (Lotus corniculatus L.) and alfalfa (Medicago sativa L.) Field studies investigated the effects of a barley companion crop, seedling year harvest management and nitrogen and phosphorus fertilization upon stands, survival and subsequent production of legumes. Seedings were made in each of two years. Stands of legumes were not affected by fertilization or harvest management, but decreased with increasing levels of companion crop competition. Death of seedlings occurred early in the establishment period and the degree of loss was similar for both species. Additional losses of plants did not occur during the establishment year. Losses of birdsfoot trefoil plants established with a companion crop occurred during the first winter following seeding. Stand reduction in the seeding year persisted for the duration of the experiment. Companion crops inhibited the growth of surviving seedlings. Growth inhibition was less when barley was clipped periodically than when it was matured to grain. In the absence of a companion crop, growth of seedlings was inhibited more by frequent clipping of thin weed stands than by allowing weeds to mature. Yields of weeds were inversely proportional to density of barley plants. Wild oats was more detrimental to seedling growth and was less readily controlled by clipping than redroot pigweed or pigeon grass. The percentage of solar radiation intercepted by barley varied from 89 in early morning or late evening to 22 at noon. Light intensity was reduced more by barley in early season and less by barley in late season than by wild oats. Yields of mixtures in the year after seeding were reduced as a result of establishment with a companion crop and to a greater degree and for a longer period of time when barley had been allowed to mature. Yield reductions of legumes were compensated for by increased grass yields. Grass grown with birdsfoot trefoil yielded significantly more in early season and significantly less in late season than grass grown with alfalfa. Greenhouse studies evaluated the influenee of soil temperature and phosphorus fertilization upon growth and phosphorus uptake of birdsfoot trefoil and alfalfa. Root growth of both species increased with increasing soil temperatures. Weight of alfalfa roots was twice that of birdsfoot trefoil at all temperatures. Top growth of birdsfoot trefoil increaeed to a greater degree than that of alfalfa with increasing temperature. The greater top growth of birdsfoot trefoil resulted in reduced root-shoot ratios. Birdsfoot trefoil produced less dry matter per cm.2 of leaf area than alfalfa. Root growth of both species increased with increasing applications of P fertilizer. Phosphorus appeared to be more important to growth at low than at high temperatures. Phosphorus and nitrogen uptake by both species increased with increasing soil temperature. Growth chamber studies evaluated the influence of low light intensities and seedling age upon growth of seedlings and distribution of accumulated dry matter. Seedlings gained weight at light intensities of 200 to 800 f.c. With decreasing light intensity, stem elongation occurred at the expense of roots. A smaller percentage of accumulated dry matter went into roots of two-week than in older seedlings. Roots of two-week old seedlings of alfalfa lost weight at 200 f.c. Laboratory studies evaluated oxygen uptake of germinating birdsfoot trefoil and alfalfa seeds. Average oxygen uptake by both species on a per unit weight basis was similar. Alfalfa, due to its greater size, had a greater oxygen uptake on a per plant basis than did birdsfoot trefoil.