Planting Dates for Early‐Maturing Soybean Cultivars

Abstract

Early planting dates may not be required for successful culture of early‐maturing soybean [Glycine max (L.) Merr.] at midlatitudes in the USA. The objectives of this research were to evaluate early‐maturing soybean cultivars in southern environments, to try to identify cultivar characteristics contributing to the fit of these cultivars into this cropping system, and to determine the range of planting dates that best discriminate among northern cultivars. Field trials, involving 12 Maturity Group (MG) II cultivars, were planted in late April to mid‐May, late May to early June, mid‐June, and mid‐July on a Maury silt loam (fine, mixed, mesic Typic Paleudalf) near Lexington, KY, in 1993 and 1994. Yield response to planting date was consistent across years, showing best yields for mid‐June plantings. Pioneer 9273 produced significantly more grain than all other cultivars. Across years and planting dates, the lowest yielding cultivar (IA 2008) produced 19% less than did Pioneer 9273, emphasizing the importance of cultivar selection. Canopy closure ratings at reproductive growth stages R2 or R5 were somewhat better related to yield than were plant mass (at R2 or R5) or plant height. The shortest cultivars had the greatest stubble losses; producers may want to avoid such cultivars. Identification of high‐yielding cultivars was clearest for the first two planting dates. Perhaps cultivars that performed well under cool, moist soil conditions were favored by the earlier planting dates. Selection of early‐maturing cultivars for production south of their traditional full‐season areas appears to be best done from early planting dates in the southerly zone.

Effects of early planting and cultivars on the yield and agronomic traits of soybeans grown in southwestern Japan

“…However, there was no significant relationship between the plant height and the seed yield for either planting date (Table 7). Steele and Grabau (1997) reported that the seed yield was significantly correlated with the plant height in late May to early June planting and mid-July planting for MG II cultivars (the growth habitat was not mentioned). Because the latitude of their experimental site (38º7' N lat.)…”

Effect of Planting Date and Starter Fertilizer on Soybean Grain Yield

“…However, starter fertilizer may be beneficial at early planting dates when the soil is often cool, which limits biological nitrogen (N) fixation and N mineralization (Agehara and Warncke, 2005; Osborne and Ridell, 2006; Stanford and Epstein, 1974). Starter fertilizer may also be beneficial when soybeans are planted late, where yield is limited by reduced light interception due to lack of canopy closure (Beuerlein and Dorrance, 2005; Bhatia et al, 1999; Steele and Grabau, 1997). Nitrogen and phosphorus (P) starter fertilizer may improve soybean yield due to increased vegetative growth when soils are cool and N is limited (early planting) or when the growing season is short (late planting) (Egli and Cornelius, 2009; Starling et al, 1998; Taylor et al, 2005; Vitosh et al, 1995).…”

“…beneficial when soybeans are planted late, where yield is limited by reduced light interception due to lack of canopy closure (Beuerlein and Dorrance, 2005;Bhatia et al, 1999;Steele and Grabau, 1997). Nitrogen and phosphorus (P) starter fertilizer may improve soybean yield due to increased vegetative growth when soils are cool and N is limited (early planting) or when the growing season is short (late planting) (Egli and Cornelius, 2009;Starling et al, 1998;Taylor et al, 2005;Vitosh et al, 1995).…”

Profitability and Risk Analysis of Soybean Planting Date by Maturity Group

“…Planting soybean early allows longer vegetative and reproductive periods (Hu and Wiatrak, 2012), which can reduce insect and disease pressures and circumvent late‐summer drought (Salmeron et al, 2014). However, planting soybean too early has been shown to decrease yields through reduced canopy development (Steele and Grabau, 1997) and delayed seedling emergence (Andales et al, 2000) if the soil is too cold or wet. Early planting of soybean can also expose the crop to late frosts, negatively impacting yields (Meyer and Badaruddin, 2001; De Bruin and Pedersen, 2008).…”