Soybean varieties from the Group 4’s down to the 000’s are INDETERMINATE varieties.
INDETERMINATE varieties continue vegetative growth even after reproductive growth (flowering) has begun. DETERMINATE soybeans (Group 5’s and later) grown in the South have vegetative growth first, then they do the reproductive growth.
BECAUSE OF THIS DIFFERENCE, THERE ARE MAJOR ADVANTAGES TO RAISING INDETERMINATE BEANS…
WHAT ARE THE ADVANTAGES OF INDETERMINATE SOYBEANS?
- THEY ARE MORE TOLERANT TO STRESS. Does the phrase “August rains make beans” sound familiar?
- YOU HAVE A WIDER REPRODUCTION WINDOW. If weather is bad for a while, indeterminate beans can hang in there longer.
- TIMING ALWAYS REVOLVES AROUND THE SUN. Flowering begins when the day length maxes out and begins to shorten.
TAKE ADVANTAGE OF THE ADVANTAGES!
I have 7 main ways for you to turn the features of indeterminate beans into benefits on your farm.
- 1
EARLY PLANTING. By planting early, your beans are bigger earlier in the season. This gives you more trifoliates to catch sunlight on the longest days of the year in June/July rather than just in July/August.
- 2
POST-EMERGE HERBICIDE APPLICATIONS CAN BE FINISHED EARLIER. Herbicides put stress on soybeans. You don’t want unnecessary stress on the beans when they are flowering and putting on pods. Finish applications before flowering, which normally begins after the longest day of the year, June 21. Besides that, after full bloom the only herbicides still labeled are volunteer corn/grass killers or PPOs like Cobra and Ultra Blazer, so the weed control options aren’t very good after that point.
- 3
BOOST FERTILITY IN ADVANCE. Soybean plants have their highest demand for nutrition once reproduction begins up until the pods are filled. If you want/need to improve fertility, get it done before reproduction.
- 4
WHITE MOLD PROTECTION BEGINS NOW. The cheapest way to reduce white mold in soybeans is to use 6 ounces of Cobra for about $3/acre just before flowering. That usually means getting it done between June 10 and June 20.
- 5
USE PGRs APPROPRIATELY. In the reproductive stages of growth, the focus needs to be on pollination and pod set. Cytokinin-dominant products have potential to help, but you have to be careful. Years ago, we used a product called Happy Gro. It was straight cytokinin and it worked well. In fact, it worked so well that it pushed plants even when there wasn’t enough nutrition to fill the pods. Now we have a much better product to work with called Amass. It improves pollen viability, increases podset, and improves photosynthesis and food production to fill more pods.
- 6
AVOID DICAMBA DRIFT. Dicamba drift is ugly in non-dicamba tolerant soybeans, but it doesn’t normally cause much yield loss if it happens BEFORE flowering. AFTER flowering, it can really destroy yields. If you have dicamba applications to make in corn or non-crop areas, get them done safely – and definitely get them done before flowering begins in soybeans.
- 7
PLANT HEALTH FUNGICIDES. Rather than spraying before flowering, with fungicides we’ve seen the best plant health benefits and yield protection when spraying at full bloom (R2) to first pod (R3).