EAST LANSING, Mich. — Soybean market prices for the 2020-2021 marketing year are projected to be below the breakeven price when land costs are included. The following is a list of recommendations from Michigan State University Extension for reducing soybean production costs without significantly affecting yields.
Planting soybeans after soybeans will reduce your yield potential up to 5%. Yield reductions can exceed 10% when soybeans are planted in the same field for a third year. In addition, long-term pests such as soybean cyst nematodes and white mold are more likely to increase when soybeans are planted after soybeans.
Reduce or eliminate tillage operations
Tillage trials conducted across the U.S. and in Ontario have shown that tillage does not significantly affect soybean yield. In some cases, no-till yields were higher than tilled yields. If fields are relatively smooth and free from harvest ruts and planting equipment is equipped to plant through the existing residue, consider planting without additional tillage. Two on-farm tillage trials conducted in 2019 support this recommendation as one pass of a spring tillage operation reduced net income by $8 per acre when both sites were combined.
Select high-yielding and pest resistant varieties
Variety selection is always one of your most important decisions when planting soybeans. By choosing varieties carefully, you can increase your yield potential by 5 to 10 bushels per acre and reduce yield losses due to white mold, sudden death syndrome, Phytophthora root and stem rot and soybean cyst nematodes.
Plant soybeans early
Numerous planting date comparisons have shown that the optimum time to plant soybeans is the first week of May. 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 better to delay planting rather than to plant into soil that is too wet. Planting early into good soil conditions may also prove to be an important way to avoid the problems associated with wet springs.
Reduce planting rates
In general, agronomists agree that 100,000 relatively uniformly spaced plants at harvest will produce the maximum economic return under most conditions. However, data collected from 49 replicated on-farm trials conducted from 2015 to 2019 show that thin soybean stands can produce surprisingly high yields when planted timely. In fact, the 100,000 seeds per acre planting rate was more profitable than the 130,000 and 160,000 planting rates when all 49 sites were combined. Higher planting rates are recommended when planting into marginal soils and planting late which will limit soybean growth. Higher rates are also recommended when planting 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.
Don’t apply nitrogen fertilizer
Hundreds of university trials have shown that nitrogen fertilizer applications to soybeans are rarely profitable. Recent on-farm trials conducted in Michigan support this as a pre-plant application of 100 pounds per acre of ammonium sulfate was profitable at only one of eight locations and it reduced net income by $16 per acre when all sites were combined.
Consider eliminating foliar fertilizer applications
Foliar fertilizer applications to soybeans are rarely profitable. This has been demonstrated in hundreds of university trials conducted across the U.S. and the Michigan on-farm foliar fertilizer trials where they increased yields in only nine of the 133 replicated on-farm trials. The exception is foliar applications of manganese fertilizers which are recommended to correct visible manganese deficiency symptoms occurring in the vegetative stages
Apply phosphorus (P) and potassium (K) fertilizers as needed to maintain critical soil test levels
The critical level for a given nutrient is the soil test level at which 95 to 97% of the crop’s yield potential will be reached with no additional inputs of the nutrient. The critical level for P is 15 ppm. Producers need to apply 0.8 pounds of P2O5 per bushel of soybeans to maintain P soil test levels. The critical K level is calculated by multiplying the cation exchange capacity (CEC) by 2.5 and adding 75. For example, the critical K level for a soil having a CEC of 10 meq/100g is 100 ppm [(10 x 2.5) + 75]. Producers need to apply 1.4 pounds of K2O per bushel of soybeans to maintain K soil test levels.
Consider applying seed treatments only when warranted
Soybean seed treatments (fungicides, insecticides, inoculants and nematicides) have produced inconsistent yield benefits in university trials. For example, complete seed treatments were profitable in only five out of 29 replicated on-farm trials conducted in Michigan from 2017 to 2019. Seed treatments may be warranted when pest problems such as sudden death syndrome or Phytophthora root rot have been verified or when planting conditions favor pest damage. Planting conditions that may promote pest damage include early planting (Pythium and sudden death syndrome), planting into grass sods (white grubs and wireworms) and when manure or green plant material has been incorporated into the soil within two weeks of planting (seedcorn 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 was evaluated in nine trials in 2012 and 2013 producing an average yield increase of 1.4 bushels per acre. Priaxor increased yields by 2.1 bushels per acre when averaged across 22 trials conducted in 2014 and 2015. These yield increases are not sufficient to cover product and application costs given the projected market prices. This is also true when an insecticide is applied with the fungicide. Foliar applications including a fungicide and an insecticide were profitable in only two of 15 on-farm trials conducted in Michigan between 2017 and 2019.
However, foliar fungicides can be an important tool for managing white mold as they have reduced disease incidence by 0 to 80% in university trials. 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, tillage, foliar fungicides and using the new Sporecaster app to aid with fungicide application decisions.
Select and apply herbicides to maximize weed control, minimize crop damage and reduce herbicide resistance
The MSU Weed Science Program evaluates commercially available weed control programs each year for GMO and non-GMO soybeans. Results are available at the MSU Weed Science website. The most profitable weed control programs year-in and year-out provide the highest level of weed control and the least crop injury. Herbicide cost was also considered but it did not affect overall profitability as much as the level of weed control and crop injury.
This article was previously published in the Michigan Soybean News Volume 12 – Issue 2.
— Michael Staton, Michigan State University Extension
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