Closing Gaps with Higher Emergence

January 29, 2019

We need to manage soybeans with the same expectations as a corn crop. It’s a phrase you’ll hear again and again in this blog.

When we look at seed attrition rates in corn, for example, growers typically expect 95 percent emergence. If 20 percent of the seed they plant doesn’t emerge, they’re on the phone to their dealer looking for answers – and so they should be.

But what happens when 20 to 30 percent of their soybean seed doesn’t emerge? It’s our experience that few growers ever call their seed dealers looking for answers. Most just accept this poor emergence as normal performance for soybeans. That needs to change. Soybean growers should be aiming for an attrition rate of 10 percent or less.

In other blogs, we’ve talked about the important role that a picket fence stand plays in helping you harvest 60-bushel soybeans. Quite simply, it’s very difficult to get that optimum stand if 20 to 30 percent of your seed is not producing viable plants. In this case, growers need to take a systems approach that looks at the genetics, environment and management (G x E x M) of their soybean crop. 

We know that the quality of our seed genetics should allow growers to achieve at least 90 percent germination rate. So why are many growers falling short of achieving that? The answer really comes down to environment and management.

Managing residue

The first thing to consider is residue management. As cereal yields increase, western Canadian growers need to take a close look at the residue coming off the combine. The tonnage is increasing and this creates extremely challenging conditions for soybean establishment.

In this situation, growers need to consider proper sizing, spreading and incorporation of residue in order to accelerate breakdown. It is important to understand that even in drier environments a little bit of tillage goes a long way in helping achieve optimum soybean stand establishment. Additional management techniques can also be employed.

Watch planting depth

Planting depth is a critical management and environmental factor. As soybean growers attempt to increase yields, many are planting earlier to maximize the length of season. Growers should remember soybean germination is highly dependent on temperature. Germination starts with soil temperatures of at least 55°F (12°C).  Early planting at, or below, two inches (5 cm) can potentially increase the attrition rate or at least make for extremely slow and variable emergence.

Maintaining consistent planting depth is also key to closing the gaps. Often growers target 1.5 inches, but actual planting depth can range anywhere from 1 to 2 inches. We need to eliminate this variability; in many cases, maintaining proper down pressure on our row unit and slower planting speeds is the answer.

Protect yield potential

When managing seed attrition rates, growers should recognize the important role seed treatments play in protecting the viability of their seed. Much of the time, stand reduction from soil pathogens such as Pythium, Rhizoctonia, Phytophthora and Fusarium goes unnoticed. When you add this potential impact to the other factors we have listed, yield loss starts to add up. In areas with a longer history of growing soybeans, there could be substantial risk to not using a treatment, especially if we get into wet conditions.

For growers, building a strong plant stand really starts when they pick up their seed at the retailer. Handle your seed with care. You don’t want the germination percentage to decline before you get the seed in the ground.

These are just a couple examples of how intensifying your management can close the gap, get a better return on your seed investment, and help you hit that 60-bushel target.

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