Texas Gulf Coast Soybean Yield Affected by Soybean Variety and Planting Date

Abstract

Soybeans (Glycine max) are planted along the upper Texas Gulf Coast from mid‐March through May to try to take advantage of early season spring and summer rains and also to complete harvest before hurricane season and fall rains become a problem. These plantings are with maturity groups (MG) IV and V and are mainly grown under nonirrigated conditions. Under normal rainfall conditions (rainfall in April, May, and early June), this study shows that a late March or early April planting date provided the highest yield although a May plant date can result in yields of greater than 50 bu/acre if rainfall is received at the proper times. However, when planting was delayed, there was a greater risk of detrimental late‐season effects from drought and southern green stink bug (Nezara viridula) or the brown stink bud (Euschistus heros). In 2004 and 2005, at both locations, soybeans planted at the early plant date took longer to reach physiological maturity than the later plant dates. Generally, the earlier the plant date, the greater number of days from planting till harvest.

Response of Soybean to Early-Season Planting Dates along the Upper Texas Gulf Coast

“…Generally, the later the planting date, the shorter the interval between soybean planting and harvest [10]. However, in the year with above average rainfall, trends toward a greater number of days from planting to harvest were noted.…”

“…Effects from glyphosate drift could easily be severe enough to invalidate the experimental results if not avoided. Drift problems with glyphosate that are severe enough to cause substantial yield losses are sometimes very difficult to detect [10].…”

“…However, in the year with above average rainfall, trends toward a greater number of days from planting to harvest were noted. This is important in that the longer the plant is exposed to the elements, whether it is an increasing chance of a hurricane or an increase in green or brown stink bug populations, the greater the chance of yield loss is [10].…”

“…In 2007, the interval between plant date and harvest date was longer for the March planted soybean than in 2006 and this was due to the above average 6 International Journal of Agronomy (Table 3) and below normal temperatures (data not shown). These weather conditions slowed plant growth and therefore extended the growing season [7,10]. When the soybean plant reaches beginning maturity, warm weather does not hasten maturity unless it causes water deficit stress and maturity is more strongly influenced by photoperiod [11].…”

“…The effect of planting date on soybean yield can vary substantially from year to year depending on variations in environmental conditions, principally rainfall amounts and distribution [9]. Soybean planted along the upper Texas Gulf Coast in late March through April can yield over 1400 kg/ha when timely rainfall is received during the growing season [10]. Soybeans planted during early April through early May in the Calhoun County area of Texas have yielded less than 1000 kg/ha and although the plants develop normally, the pods in many instances do not contain any soybean.…”