Delayed Double-Crop Soybean Planting and Maturity Groups

Chad Lee and Jim Herbek, Extension Agronomists, University of Kentucky

Double-crop soybean planting often
occurs the same day as wheat harvest.

The delayed wheat harvest is delaying double crop soybean planting. If double crop soybeans are planted by late June or early July, there is no need to adjust relative maturities. If double-crop planting ventures into the second week of July, then producers may want to reduce the relative maturity by 0.5 to 1.0 in an attempt to avoid frost damage in the fall.

As a refresher, soybean relative maturities of 4.0 to 5.0 would be considered full-season in far western Kentucky and southern Kentucky, which includes the Purchase Area and areas south of the Western Kentucky Parkway. Relative maturities from about 3.5 to 4.5 would be considered full-season in northern and eastern Kentucky, which would include the areas north of the Western Kentucky Parkway, the Central Bluegrass and Eastern Kentucky.

Soybean seeding rates should be around 160,000 to 180,000 seeds per acre for double-crop soybeans. Even though double-crop planting is delayed, that delay in planting maybe offset by the most soils this year. That moisture and the warm temperatures should allow for quicker germination and growth.

Watch Seeding Depth on Soybeans

Chad Lee and Jim Herbek, Extension Agronomists, University of Kentucky

With soil conditions dry in the upper 3 to 4 inches in many fields, farmers are tempted to place soybean seeds deeper in search of moisture. In general, soybeans should be placed about 1 to 1.5 inches deep and no deeper than 2 inches in dry conditions. The more ideal situation would be to wait for a rain and then plant 1 to 1.5 inches deep. However, many growers believe they cannot wait for the ideal situation because of the total number of acres they need to cover.

Soil type and soil condition influences soybean planting depth. The following are our general guidelines for soil conditions and soybean seed placement. Dry, silt loam soils (the majority of our fields at this time) should have soybeans placed no deeper than 2 inches, even if soil moisture is deeper. When planting in sandy soils (very few of those in Kentucky), soybeans should be placed about 2 inches deep. Heavy clay soils require soybeans to be planted about 1 to 1.5 inches deep. Cool, wet soils (not many of those at this time) cause slower germination and soybeans can be placed about 1 inch deep.

For more information on this, see: Soybean Planting in Kentucky.

Do as I Say not as I Do ... Challenges with Planting

Chad Lee, Grain Crops Extension Agronomist, University of Kentucky

Often this spring, I have warned farmers not to plant one day too early to avoid "mudding in" the corn or soybeans. When we plant just one day too soon, we increase the chances of getting sidewall compaction and run a higher risk of keeping the roots bound within the furrow. Roots trapped in the furrow can lead to some real problems later in the growing season. However, yesterday, I disregarded all of that caution and mudded in soybeans.

Soybean Planting

Jim Herbek, Extension Agronomist, University of Kentucky

A very wet April has prohibited any early soybean planting. Little, if any, soybeans have been planted as of April 25. Wet weather forecast through the end of April indicates soybean planting may not get started until after May 1. Be patient; we still have time to get good yields on soybeans. Recent soybean planting date research in west Kentucky indicates soybean yield losses do not normally occur until after mid-May. So we still have about three weeks to plant soybeans for top yield potential. Soybeans planted after May 15 to 20 has an average yield loss of ½ bu per acre per day, and soybeans planted in early June has an average yield loss of 1 bu/acre/day. Currently, soil temperatures are adequate for planting soybeans, but wet soil conditions are not suitable. Planting into wet soil conditions can result in sidewall compaction, poor emergence, and a reduced soybean stand.

Planting soybean into sod, 2011

Chad Lee and Jim Herbek, University of Kentucky
email: Chad Lee or Jim Herbek

Planting soybean into sod is an option for producers looking to increase acres.  Soybean could generate a gross return of  $500 per acre, or more, depending on yield and marketing. Soybean is also a good option for producers who need to renovate pasture and hayfields. Some producers have a lot of experience with soybean while others may be looking at the crop for the first time. The following guidelines attempt to be applicable to both groups of producers.

Consider the following when converting sod to soybean: