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2 steps to boost soybean yield

Last year at this time I wrote about tracking the moisture level in corn that was still in the field. With the snow depths this year, I’m thankful producers are not out pulling ears every week, worrying about this issue again.

Corn acreage in our region has increased significantly in the past five years, but soybeans still have twice the acreage and get about half the publicity. The biggest reason I see for this is the difference in how yield is determined between these crops. We have a lot more influence over corn yields than over soybean yields.

The biggest yield determiner in soybeans is Mother Nature. I have seen countless university and private soybean yield studies resulting in equal numbers of positive and negative yield responses to agronomic trials on population, seed treatments and post-applied inputs.

A recent study from Ontario showed a high-yield soybean trial designed simply to get the highest yield possible out of a larger-sized plot. The study included eight different products along with the seed. Researchers did achieve 75 bushels per acre in their plot, which is excellent. However, the untreated check plot ran 72 bushels per acre. It doesn’t take much figuring to see that the higher-yielding plot lost in overall profit.

Soybean genetics are at the point now, even in the Upper Great Plains, where excellent top yields in soybeans are achievable. But how do we preserve those yields? I really think this question should be the focal point in raising soybean yields. Since Mother Nature is our biggest foe, how do we prevent her from robbing us of yield? There are many practices and products to consider. I’ve tested the following and each has had consistent returns.

Seed-applied fungicides have given me an economic return most of the time. They won’t net an additional 5 bushels per acre every year; however, I’ve seen about 1 bushel per acre in 12 trials over the last six years. With low input cost, this is a very positive return. Make sure the treatment you use is right for your area, though.

We use a higher rate of Metalaxyl (Allegiance) in our location, due to higher phytophthora pressure in our soils. Seed treatments are most highly recommended at the beginning of the planting season due to cooler soil temperatures at that time. But rhizoctonia, phytophthora and fusarium are all active in warmer soils as well — so use treatment throughout the entire planting season.

Another thing to consider is planting date. I’ve had great luck with our early-planted soybeans. We are able to get a larger plant by flowering, enabling the plant to keep a higher percentage of those flowers to later turn into pods. I have not figured out why soybeans haven’t been pushed earlier like sugarbeets have. They do not respond any differently to a frost. And normally, a crop-killing frost will hit us in late May when mid-May planted beans will be affected as well.

This spring, try some yield preservation tactics on your soybeans. Let’s get our yield growth curve to match what corn has done in the past five to 10 years. High-yield soybeans shouldn’t be an anomaly in this region!

Spelhaug is an agronomist with Peterson Farms Seed, Harwood, N.D. Contact him at 866-481-7333, or visit


This article published in the March, 2011 edition of DAKOTA FARMER.

All rights reserved. Copyright Farm Progress Cos. 2011.