Soybean growth and development in various management systems and planting dates. Crop Sci

ABSTRACT lar grain yield occurred despite significant differences in total DM yield over the growing season. Overproduc-Soybean [Glycine max (L.) Merr.] has the ability to produce similar tion of vegetative DM does not always reduce seedyields across a broad range of management systems and planting dates. Our objective was to better understand growth factors affecting yields, but improved partitioning of dry weight could yield component compensation in the upper Midwest under different result in higher seed yields (Shibles and Weber, 1966; management systems. An older cultivar, Hardin, and two newer culti- Beuerlein et al., 1971). vars, DeKalb CX232 and Spansoy 250, were grown in five management Total DM is influenced by CGR, relative growth rate, systems during four growing seasons from 1997 to 2000. Four of the relative leaf area growth rate, and net assimilation rate five management systems were located near Arlington, WI, on a silt (Hunt, 1982). Crop growth rate is a prime dynamic loam soil consisting of conventional and no-tillage systems with and growth factor to study since it reflects canopy assimila-without irrigation. The fifth management system was located near tory capacity, and affects total DM levels and equili-Hancock, WI, on a conventionally tilled, irrigated sandy loam soil. brates through adjustments of LAI and/or net assimila-Yield component compensations gave similar grain yield among culti-tion rate (Imsande, 1989). Shibles and Weber (1966)vars, planting dates, and management systems. At R6, CX232 and Spansoy 250 averaged greater dry matter (DM) accumulation, leaf demonstrated that optimal CGR and yield resulte