EARLY-SEASON PRODUCTION SYSTEMS UTILIZING INDETERMINATE SOYBEAN

Soybean [Glycine max (L.) Merr.] yield and yield components can be influenced by production practices that affect soil moisture and plant architecture. This study evaluated the effects of variations in soil moisture and inter-row spacing on seed yield and yield components of an indeterminate soybean grown in an early-season production environment in south-central Texas. 'Williams 82' soybean (Maturity Group III) was planted in mid-April in 1988 and 1989 near College Station, TX (30-degrees 32' 33" N lat) in a Ships clay (very fine, mixed, thermic Udic Chromusterts) that is intergraded with Weswood silt loam (Fluventic Ustochrepts). Harvest occurred in late August. Soil moisture regimes were irrigation and no irrigation; inter-row spacings were 0.36 and 1.02 m. Seed yields were greater in 1989 (4260 kg ha-1) than in 1988 (3550 kg ha-1). Soil moisture level and row-spacing treatments had no effect on seed yield either year. Year-by-inter-row spacing interactions were significant for single seed mass and total seed and pod number. Seed size was greater in 1989 than in 1988. The year-by-soil moisture level interaction was significant for mean seed per pod. Both years, yield component characteristics were more consistent in 1.02-m rows than in 0.36-m rows. These results indicate that adequate yields, with maturation in late-August, are possible using an adaptable indeterminate soybean in an early-season production environment in south-central Texas.