MSU Expert: Soybean Seed Applied Inoculant Best Practices

Nitrogen fixation is a result of the symbiotic relationship of Rhizobia bacteria and soybean plants. These bacteria fix atmospheric N2 into the NH4 form, which is useful to the plant. In return, the plant provides the bacteria with carbon photosynthesis products (dicarboxylic acids), which the bacteria use as food. Establishing rhizobia or inoculation in a field that has never grown soybean is needed to ensure nitrogen fixation. Elmore (1996) suggests when and how soybeans should be inoculated, and provides recommendations on inoculate type to use. Soybeans grown on soils without a rhizobia population will use available soil nitrogen, and if soil nitrogen levels are low because of soil type, soil erosion, etc., the symptoms of nitrogen deficiency may occur.

Field studies in Northern Michigan showed 45% and 23% soybean yield increases in 2004 and 2005 where inoculant was used and fields had not seen a previous soybean crop. Soybean plant coloration differences were obvious in this study, as inoculated plots appeared much greener.

On other Michigan sites with a history of soybean cropping, soybean seed inoculation increased yield by an average of 1.3 bushels, with significant increases at 6 of 14 sites from 2003 to 2005. Because most commercially available inoculant products are relatively inexpensive, the 1.3 bushel/acre expected average yield increase will generally cover application costs. Therefore, it is recommended to apply Rhizobium inoculant to soybean seed each time you plant soybeans. This is especially true on sandy soils, where it is more difficult for the Rhizobia to survive from one season to the next. Also, it is important to inoculate on any soil if soybeans are to be grown for the first time.

Two types of inoculants can be used: seed-applied and soil-applied. The seed-applied inoculate is more effective when mixed with water to form a slurry that is used to coat the seed. This should be done as close to planting time as possible, preferably within several hours. The soil-applied inoculate may be easier to apply than the seed-applied inoculate, but it is more expensive on a per acre basis. Thus, seed applied inoculant is generally the method of choice for most growers.

In addition to the recommended short time period between seed applied inoculant application and planting, there are other potential challenges associated with proper soybean seed inoculation. Care should be taken in applying inoculant to fungicide or insecticide treated seed. Fungicide and insecticide labeling should be checked to ensure that the particular pesticide product is compatible with Rhizobium inoculant. Potter (2004) conducted field trials to examine the effects of inoculating soybean seed with rhizobium, seed applied insecticides and fungicides, and combining bacterial inoculant, insecticidal and fungicidal products in Southwest Minnesota. For the trial, one bacterial inoculant, two insecticidal products, and two fungicidal products were used. There were 12 treatment combinations among the 5 different products tested. The results showed that crop injury was not observed with any treatment. Further, differences in root disease, soybean height, nodulation or yield were not observed among treatments.

A three-year Michigan study tested the effects of combinations of seed inoculant, fungicidal seed treatment and insecticidal seed treatment. Inoculant was used alone, in combination with either Apron Maxx, Cruiser, or Gaucho, and in combination with Apron Maxx and one of the two seed applied insecticides. Results of the trial showed that in fields where soybean seed inoculation did significantly increase yields versus non-inoculated seed, the addition of insecticidal and fungicidal seed treatments did not significantly negate the observed yield increases.

Finally, Rhizobia do not function below pH 5.0 and molybdenum, which is important for Rhizobia nodule formulation, can be deficiencient at pH levels below 6.0. Liming of low pH soils is the best solution for these challenges.

Recommendations

  • Inoculates should be stored in a cool place and not exposed to the sun prior to use. Refer to product labels for specific handling recommendations.
  • The safest approach is to buy fresh inoculate each year.
  • Seed should be planted within four hours of inoculation. New products are being developed with a longer preplant application interval, but data on the performance of these products is somewhat limited.
  • When applying a fungicide or using fungicide treated seed, be sure the fungicide has dried before applying inoculate to the seed. Inoculate should NOT be mixed with fungicides and applied together.
  • Refer to product labels for specific handling recommendations.
  • When loading a drill or planter using an auger, inoculation materials (liquid or dry) should be added to the seed as it enters the auger for thorough application.
  • When loading a drill or planter from bags, fill the seed box to a depth of three inches and scatter the appropriate amount of inoculate over the seed and mix it in thoroughly. Continue to add seed in six-inch deep layers, treating each until the seed box is filled.
  • With some dry materials it may be desirable to slightly moisten seed to increase the adherence of inoculate. Individual seeds need no more than a three to five percent coating of dry material.
  • Liquid materials will usually cover most of the seed.
  • Seeding equipment should be calibrated using treated seed.
  • Lime soils used for soybean production according to soil test recommendations.

SOURCE: Michigan State University Extension

Leave a Reply

Crop Inputs Stories

Crop InputsLand O’Lakes Announces Minnesota Water Quality Partnership
May 25, 2016
Governor Mark Dayton and Land O’Lakes, Inc. President and CEO Chris Policinski today announced a new public-private partnership to protect Read More
Corn close up
Crop InputsArysta LifeScience Establishes Global Headquarters In RTP
May 25, 2016
Arysta LifeScience has announced plans to relocate its global headquarters from West Palm Beach, FL, to Cary, NC, over the Read More
Southern States Cooperative
glyphosate
Crop InputsWHO: Glyphosate ‘Unlikely’ To Cause Cancer
May 16, 2016
Via Reuters.com reporter Kate Kelland: The weed-killing pesticide glyphosate, made by Monsanto and widely used in agriculture and by gardeners, Read More
Trending Articles
Eric SfiligojPity The Monsanto Haters
May 23, 2016
An old saying goes thus: “Be careful what you wish for. You just might get it.” Given current events, there Read More
Monsanto Luling Plant
Crop InputsReport: Bayer Eyeing Monsanto For Possible Mega-Merger
May 16, 2016
Bayer AG is exploring a potential bid for U.S. competitor Monsanto Co. in a deal that would create the world’s Read More
Aerial Drone
Precision AgA Deeper Dive Into The Future Of Precision Ag
May 9, 2016
For about two decades now, through the good and the bad times, the ups and the downs inherent in agriculture, Read More
Palmer amaranth in soybean stubble
HerbicidesWSSA: Billions In Potential Economic Losses From Uncontrolled Weeds
May 4, 2016
What losses would corn and soybean growers experience if they were forced to eliminate herbicides and other control techniques from Read More
Eric SfiligojReasons For Hope In Commodity Prices
May 2, 2016
For many months now, the doomsayers have ruled the day in agriculture. Too much supply with too little demand would Read More
Eric SfiligojMissing The Family Ties In Agriculture
April 25, 2016
By its nature, the agriculture market is cyclical. Up and down cycles come and go with a regular pattern. For Read More
Latest News
ManagementWashington Visit and Bayer/Monsanto Deal Update
May 26, 2016
Editors Paul Schrimpf and Eric Sfiligoj discusses a recent trip to DC and the latest news on the proposed pairing Read More
Fertilizer closeup in hand
Industry NewsVerdesian: Striking A Balance Between Yield & ROI
May 26, 2016
Finely tuned nutrient management plans are helping farmers throughout the U.S. improve nutrient use efficiency, increase return on investment (ROI) Read More
Crop InputsLand O’Lakes Announces Minnesota Water Quality Pa…
May 25, 2016
Governor Mark Dayton and Land O’Lakes, Inc. President and CEO Chris Policinski today announced a new public-private partnership to protect Read More
Soybean Plant closeup
Industry NewsMonsanto Rejects Bayer Bid; Open To More Talks
May 25, 2016
Monsanto Co, the world’s largest seed company, turned down Bayer AG’s $62 billion acquisition bid as “incomplete and financially inadequate” Read More
Corn close up
Crop InputsArysta LifeScience Establishes Global Headquarters In R…
May 25, 2016
Arysta LifeScience has announced plans to relocate its global headquarters from West Palm Beach, FL, to Cary, NC, over the Read More
fertilizer blending and storage, Top 100
BlendersCHS Dakota Expansion Features AGCO’s GSI InterSys…
May 25, 2016
The continued growth of precision agriculture has increased farmer use of customized fertilizer blends best-suited for their soil conditions. Several Read More
ManagementAgriculture 3.5: A Bumpy Road Ahead
May 24, 2016
You may have read my article a few years ago on Agriculture 3.0, which is a term I coined to Read More
Topcon’s X30 display with CropSpec sensors
EquipmentGPS Autosteer Systems: Product Updates From Precision A…
May 24, 2016
Throughout 2015 GPS Steering solutions continued to evolve from what was once an after-market add on, to today’s cab where Read More
Trimble TMX-2050 In-Cab Display
Eric SfiligojThe Precision Ag Revolution Continues
May 24, 2016
It’s funny how much “the first time” tends to mean to someone as they get older. I sometimes can’t recall Read More
Eric Wintemute, AMVAC
Precision AgAMVAC Ups The Ante With New Precision Ag Technology
May 24, 2016
A potentially industry-changing at-plant soil treatment system from American Vanguard Corp., or AMVAC, is coming soon to large growers in Read More
Dry and Liquid Plant
CropLife 100CropLife 100 Map
May 24, 2016
The new CropLife 100 map shows the locations of each of the headquarters of the 2015 CropLife 100 retailers. The interactive Read More
Southern States Cooperative
Corn Field
Industry NewsTiger-Sul Names Veteran Account Manager To Lead Central…
May 23, 2016
With the continuing growth of the sulphur bentonite and precision crop nutrient industry, global agriculture firm H.J. Baker has announced that Read More
Bayer sign
Industry NewsReuters: Bayer Defies Critics With $62 Billion Monsanto…
May 23, 2016
German drugs and crop chemicals group Bayer has offered to buy U.S. seeds company Monsanto for $62 billion in cash, Read More
Eric SfiligojPity The Monsanto Haters
May 23, 2016
An old saying goes thus: “Be careful what you wish for. You just might get it.” Given current events, there Read More
Industry NewsCompass Minerals Hires Industry Veteran To Lead Plant N…
May 19, 2016
Compass Minerals has hired plant nutrition industry veteran Vatren Jurin to steer the company’s portfolio expansion into specialty liquid micronutrient Read More
ASMARK Retailers LIVE! Tour 2016 Group shot The Andersons
CropLife 100The Andersons Rejects Unsolicited Proposal From HC2
May 19, 2016
The Andersons, Inc. has announced that its Board of Directors has rejected two non-binding, highly conditional, unsolicited proposals from HC2 Read More
glyphosate
Crop InputsWHO: Glyphosate ‘Unlikely’ To Cause Cancer
May 16, 2016
Via Reuters.com reporter Kate Kelland: The weed-killing pesticide glyphosate, made by Monsanto and widely used in agriculture and by gardeners, Read More