Given a very warm vegetative period, flowering can start before the dark period begins to lengthen. Since flowering response of corn and sorghum is more temperature dependent than that of soybeans, accumulated growing degree days are reliable for estimating corn and sorghum growth stages but not for estimating soybean growth stages. Planting Date Considerations Soil temperature is an important aspect. Planting into seedbeds that are in the low fifties is not advisable unless soil temperatures are rising rapidly. Sixty degrees Fahrenheit is a good target at which to begin planting.
Soybeans have a unique ability to yield well when planted over an extended time period.
This permits them to complement other crops in Nebraska's cropping system. The data in Table I , which are averages of six indeterminate varieties, illustrate this well. Soybeans planted in May were the most productive. Yields were considerably lower after mid-June. Podding height dropped off considerably in July.