Spring checklist for improving soybean yields
April 17, 2008 - Author: Mike Staton, MSU Extension educator and Soybean 2010 coordinator
The following checklist summarizes management practices that are proven to contribute to high-yielding soybeans.
Inspect, repair and calibrate planting equipment. Uniform seed spacing in the row will improve yields. Small seed will plant more evenly and will experience less mechanical damage than large seed when planted with a drill equipped with a fluted metering system. Always calibrate your drill by seeds per foot of row or seeds per acre. Recalibrate whenever seed size changes.
Control weeds prior to planting. Always plant into weed-free fields. Delayed burn-down applications have resulted in yield losses of 8 bushels per acre in MSU research trials. Tillage and/or herbicides can be used to control weeds.
Broadcast potash on coarse-textured or organic soils if needed. Fall applications of potash are not recommended on coarse-textured soils having CECs less than 6 meq/100 g or on organic soils due to the potential for leaching losses.
Apply phosphate fertilizers if recommended. MSU recommends applying maintenance level phosphorus (0.8 lbs. of actual P2O5 per bushel) when phosphorus soil test levels are between 15 and 30 ppm. No phosphorus is recommended when soil test levels exceed 40 ppm.
Plant into good soil conditions. Adequate and uniform soil moisture, soil temperatures higher than 50oF and a level surface will promote uniform seedling germination and emergence.
Plant soybeans early. The first two weeks of May is considered the ideal planting window for soybeans in the lower half of the Lower Peninsula. Yield losses of 0.6 of a bushel per acre per day can occur when planting is delayed past May 15. Please see the Soybean Facts fact sheet entitled “Early-Planted Soybeans - Risks, Benefits and Recommendations ”when planting prior to May 1. You can find this bulletin at http://web1.msue.msu.edu/soybean2010/.
Inoculate seed whenever soybeans are planted. Researchers from Michigan State University and Ohio State University report average yield increases of 1.3 bushels per acre from using inoculants on fields having a history of soybean production.
Consider a soil-applied residual herbicide application followed by a post-emergence application. Benefits include: reduced early-season weed competition, consistent control of weeds that emerge over a long time period, consistent control of hard-to-control weeds and herbicide resistance prevention.
Plant at the optimum seeding rates. Plant 175,000 seeds in 7.5” rows, 150,000 seeds per acre in 15” rows and 130,000 seeds per acre in 30” rows.
Plant in narrow rows. University research trials have shown that planting in narrow rows significantly increases soybean yields.
Plant at the optimum depth. Plant beans between ¾-inch and 1-1/4-inch deep. In general, plant at the shallower end of the range when planting early and in no-till, and plant at the deeper end of the range later in the season.
Plant a range of maturity groups. Planting a range of soybean maturity groups spreads your risk during the growing season, allows more of the crop to be harvested at the optimum stage and allows for timely wheat planting.
Use seed treatments where warranted and provide uniform coverage of the seed. Fungicide seed treatments are warranted when planting very early and/or where pythium is known to be a problem (Southwest Michigan). Insecticide seed treatments are warranted when seedcorn maggot, wireworm or bean leaf beetle damage is expected.
Monitor fields closely beginning at emergence. Diagnose emergence problems early. Emergence can take six to 18 days depending on soil temperature and soil moisture conditions. If slow and uneven emergence occurs, dig up the delayed plants and look for disease or insect damage. Plant stands of 100,000 plants per acre will produce optimum yields if the plants are relatively evenly spaced. After emergence, continue checking fields for bean leaf beetles and black cutworms. Monitor weed heights and use this information to time post-emergence herbicide applications.