MSU Extension Soybeans

Agricultural economists are projecting tighter profit margins for soybeans in 2023 than those realized in 2021 and 2022 due to rising input costs. Because of this, soybean producers will need to manage production costs carefully. The following research-based recommendations from Michigan State University Extension will help producers reduce production costs without adversely affecting yields.

Reduce or eliminate tillage operations

Tillage trials conducted across the U.S., such as those in the study “No-tillage soybean production” from Iowa State University, and in Ontario have shown that tillage does not significantly affect soybean yield. A single tillage pass performed in the spring was compared to an untilled control at eight locations in Michigan from 2019 to 2021. Tillage increased income at only two locations. If your fields are relatively smooth and free from harvest ruts and your planting equipment is equipped to plant through the existing residue, consider planting without additional tillage. Tillage operations may be necessary to level harvest ruts prior to planting and may be beneficial when planting very early (last week of April).

Select high-yielding and pest resistant varieties

Variety selection is one of your most important decisions when planting soybeans. Based on data from the Michigan Soybean Performance Reports, choosing varieties carefully can increase your yield potential by 5 to 12 bushels per acre and reduce yield losses due to white mold, sudden death syndrome (SDS), Phytophthora root and stem rot and soybean cyst nematodes without increasing costs. Strategically match varieties with the pest pressure and productivity of your fields.

Plant soybeans early

Numerous planting date trials show that planting soybeans early maximizes yield potential. Yield losses of 0.3 to 0.6 bushels per acre have been documented for each day that planting is delayed after May 8. However, it is far better to delay planting than to plant into soil that is too wet.

Reduce planting rates

Results from 67 replicated on-farm trials conducted in Michigan from 2015 to 2021 show that low planting rates can produce surprisingly high yields. In fact, the 100,000-seeds-per-acre planting rate was more profitable than the 130,000 and 160,000 planting rates when all 67 sites were combined. Higher planting rates are recommended when planting in marginal soils and when planting late. Higher rates are also recommended in northern Michigan, where early maturing varieties are planted. Under good planting conditions, planting rates should be 15 to 20% higher than your intended harvest populations.

Base lime applications on soil test results

Soybeans will generally perform well at soil pH levels between 6.0 and 7.0. However, the optimal range is between 6.3 and 6.5 as this range maximizes nutrient availability and biological nitrogen fixation, while minimizing soybean cyst nematode population growth. Variable-rate lime applications are highly recommended to achieve more uniform soil pH levels within fields.

Don’t apply nitrogen fertilizer

Hundreds of university trials have shown that nitrogen fertilizer applications to soybeans are rarely profitable. This has been confirmed in replicated on-farm trials conducted in Michigan.

Don’t apply foliar fertilizers

Foliar fertilizer applications to soybeans are rarely profitable. This has been demonstrated in hundreds of university trials (see “Foliar Fertilizers Rarely Increase Yield in U.S. Soybean” from the Soybean Checkoff), and in the Michigan on-farm foliar fertilizer trials, where only 15 of the 156 replicated trials were profitable. The exception is foliar application of manganese sulfate, which is recommended to correct visible manganese deficiency symptoms.

Consider eliminating starter fertilizer

Eleven on-farm 2x2 starter fertilizer trials were conducted in Michigan in 2021 and 2022. In two of the trials, the starter fertilizer increased income by $4.50 per acre. However, when all 11 sites were combined, the starter fertilizers decreased income by $30 per acre. In-furrow fertilizer placement has not consistently increased soybean yields in Michigan on-farm trials either. In-furrow fertilizers increased yields in only two of 11 trials.

Apply potassium (K) fertilizers as needed to maintain critical soil test levels

Soybean producers can make important potash allocation decisions by comparing their K soil test levels to the values listed in Table 1. If your K soil test levels are at least 10 ppm above the critical level, eliminating potash applications should not adversely affect 2023 soybean yields or drop K soil test levels below the critical level. However, if your soil test levels are less than 10 ppm above the critical levels, a maintenance level K application is warranted. The K levels reported in table 1 are Mehlich III values. If your soil test reports K levels as ammonium acetate values, multiply by 1.14 to convert to Mehlich III.

Apply seed treatments only when warranted

Soybean seed treatments including fungicides, insecticides, inoculants and nematicides have produced inconsistent yield benefits in university trials. For example, base seed treatments containing multiple fungicides and an insecticide were profitable in only 10 out of 31 replicated on-farm trials conducted in Michigan from 2017 to 2020. The average yield increase was 1.4 bushels per acre, which is about breakeven. Seed treatments may be warranted when pest problems such as SDS, or Phytophthora root rot have been verified or when planting conditions favor pest damage. Examples include early planting (Pythium and SDS); planting into grass sods (white grubs and wireworms); and when manure or green plant material has been incorporated within two weeks of planting (seed corn maggot).

Consider eliminating foliar fungicide applications unless field and weather conditions are favorable for white mold

Prophylactic foliar fungicide applications have produced modest yield increases in Michigan on-farm research trials. Stratego YLD, Priaxor, Miravis Neo and Delaro Complete have been evaluated in on-farm trials in Michigan from 2012 to 2023 (Table 2).

However, foliar fungicides rated as providing good white mold control (Aproach, Endura, Lektivar, Omega, and Propulse) can be important tools for managing white mold. Using a combination of tactics is recommended when planting soybeans into fields having a history of white mold. These include wide rows, resistant varieties, reduced planting rates, irrigation water management, careful tillage decisions, foliar fungicides, and using the Sporecaster App to assist with fungicide application decisions.

Select and apply herbicides to maximize weed control, minimize crop damage and reduce herbicide resistance

Christy Sprague, MSU weed scientist, evaluates commercially available weed control programs each year. The most profitable weed control programs year-in and year-out provide the highest level of weed control and minimize crop injury. The cost of the weed control programs is also considered, but it does not affect overall profitability as much as the level of weed control and crop injury.

Reducing production costs and improving efficiency will help soybean producers respond to the projected high input costs.

This article was produced by a partnership between MSU Extension and the Michigan Soybean Committee and originally published in the 2022 Michigan On-farm Research Report.