Alfalfa Yield Component Responses to Seeding Rate Several Years after Establishment

Abstract

Little information is available regarding the relationships of alfalfa (Medicago sativa L.) forage yield with yield components in seed‐established stands grown under dryland conditions. Field experiments that included two cultivars and 15 seeding rates ranging from m 2.2 to 33.6 kg pure live seed ha−1 were established in 1985 at Brookings and Highmore, SD. The objective was to determine seeding rate effects on components of alfalfa forage yield and on plant morphology several years after establishment. In the seeding year, plant density increased linearly with seeding rate at both locations. Yield components were determined in 1988 and 1989. Mean alfalfa yield during 1988 and 1989 was optimum at the 13.4 kg pure live seed ha−1 rate at Brookings, but did not respond to seeding rate at Highmore. Plant density continued to be affected by seeding rate 4 yr after establishment, but greater mortality at high seeding rates caused the response to deviate from linearity. Shoots per plant were negatively correlated with plant density (r = –0.73, P = 0.01). Shoot weight did not respond to seeding rate at Brookings but declined linearly with seeding rate at Highmore. Nevertheless, path analysis suggested that shoot weight was the major influence on alfalfa yield at both locations. Leaf‐to‐stem ratio and shoot length were not affected by seeding rate. Alfalfa yield components are affected similarly by plant density in seed‐established and transplanted stands. Although yield may not be affected by plant density, shoot weight may be affected because of differences in plant competition.

Optimal plant densities of lucerne (Medicago sativa) for pasture production and soil water extraction in mixed pastures in south-western Australia

“…The conclusion that higher plant densities resulted in higher lucerne biomass and total biomass in most years supports the findings of Volenec et al (1987), Kephart et al (1992) and Dear et al (2007b). However, this is probably because plant densities in all of these studies, especially in our study, were relatively low (Hall et al 2004).…”

“…Farming systems which have included lucerne in the rotation in this region usually consist of lucerne based pastures for 3-4 years followed by crop (Latta et al 2001) so the benefits of a higher plant density were reduced by possibly one year. Previous research has generally found that plants in higher density populations experienced higher mortality rates than lower-density populations (Kephart et al 1992;Hall 1993;Nelson et al 2001;Dear et al 2007b). However, densities in these studies were higher than what we achieved at both Esperance and Katanning.…”

Análise de trilha para rendimento de sementes em trevo vermelho (Trifolium pratense L.)

“…Porém, a mesma também se faz presente em trabalhos com plantas forrageiras, avaliando os componentes do rendimento de sementes (Iannucci & Martiniello, 1998;Lord & Kelly, 1999), bem como os componentes da produção de matéria seca (Gumber et al, 1988;Shukla & Malaviya, 1989;Kephart et al, 1992).…”

Influence of year and row spacing on yield component andseed yield in Alfalfa (Medicago sativa L.)

“…It reported that alfalfa plants were several inches shorter, lodge less, and more easily to pollinating insects in thinned stands than those in unthinned stands (Pederson, 1957). The recommended row spacing in these studies changed from 20 to 91 cm (Kephart et al, 1992). These studies indicate that low bush density and greater row spacing are important elements for increasing alfalfa seed production.…”