Soybean Inoculation: Its Science, Use And Performance

The soybean is a legume who’s seeds generally contains 37% to 45% protein by weight. Depending on the protein content, a bushel of soybeans will cont ain between three and four pounds of nitrogen. The production of a 60-bushel per acre crop requires in excess of 300 pounds of nitrogen.

Some of the nitrogen comes from the oxidation of soil organic matter with the balance produced by bacteria residing in nodules on the plant’s roots. Each legume species requires different bacteria to fix nitrogen from the air and produce ammonium for use by the plant.

The Inoculation Process

The bacterial strain of Rhizobium used by soybean is Bradyrhizobium japonicum, and the process by which it gains access to the plant is very complex, but fairly well understood. Soybean plants release chemical signals (flavanoids) into the soil as they germinate and the plants emerge. These signals are picked up by the rhizobia in the soil and in inoculation material, and produce a return signal “Nod factor signal” to the plant. This return signal results in the plants’ roots preparing for infection by the bacteria.

The Nod factor signal causes the root hairs to curl, trapping rhizobia that are present on the surface of the root. An infection thread develops, and the rhizobia multiply until they reach the inside of the root. The cells of the root also begin to divide and form a specialized structure called a nodule. The rhizobia continue multiplying inside the nodules increasing their size. The enzyme (nitrogenase) that fixes nitrogen from the air to form ammonium cannot function in the presence of oxygen. In order for nitrogen fixation to occur, the plant must produce Leghaemoglobin in side the nodule to absorb oxygen in the root to prevent it from interfering with the nitrogen fixation process. Since Leghaemoglobin is red, the inside of an actively fixing nodule is pink. Sugars produced in the leaves travel to the root system and move into the nodules to provide energy that the rhizobium uses to extract nitrogen from the air to make the nitrogen compounds which the plant then uses to produce protein. The better this process works, the greater the grain yield and amount of protein produced.

Both plant and bacteria genes govern the entire nitrogen fixation cycle. Stresses on the bacteria or the plant such as cold, flooding, drought, and low soil pH can all interfere with this process. Cold temperatures delay the recognition of both the plant and bacteria signals. The plants and bacteria have to produce more signals in order to begin nodulation, which delays the onset of nitrogen fixation. Once enough signal is received and nodules develop, ammonium is produced and provided to the crop.

Drought reduces the moisture in the soil that protects the bacteria while it lives on the seed surface after planting. A dry seedbed and dry seed will quickly draw moisture from the inoculation material causing the bacteria on the surface of the seed to dry and die. If enough bacteria die, there will be little nodule formation and insufficient ammonium production for a good yield. Other stresses, including low soil pH, seed treatment chemicals, and starter fertilizers, can also kill the bacteria or inhibit nodulation. In fact, soil nitrogen levels in excess of 30-50 lbs per acre can stop both nodulation and nitrogen fixation altogether.

Click here to read Dr. Beuerlein’s full .pdf “Soybean Inoculation; Its Science, Use And Performance.”

SOURCE: Dr. Jim Beuerlein, The Ohio State University

Leave a Reply

Seed/Biotech Stories

Monsanto sign
Crop InputsCould a Monsanto-Bayer Union Be 2 Weeks from Fruition?
August 24, 2016
Via STLToday.com (The St. Louis Post-Dispatch): Merger talks between Monsanto Co. and Bayer AG are advancing after a series of Read More
Seed/BiotechMycogen Seeds Research Station Celebrates 30th Anniversary
August 9, 2016
The Mycogen Seeds research station in Mount Vernon, IN, is celebrating 30 years of corn hybrid innovation. To mark the Read More
Peanut field
Crop InputsVerdesian Introduces New Inoculant For Peanuts
July 28, 2016
As planning begins for the next growing season, Verdesian Life Sciences adds Primo Power CL, a new liquid inoculant, to Read More
Soil Young Corn
Crop InputsSmithsonian: 5 Things to Know About New GMO Labeling Bill
July 27, 2016
On July 14, the House of Representatives passed a bill requiring large food companies to label products containing genetically modified Read More
Trending Articles
ASMARK 2016 Retailers Live! Tour - CPS
CropLife 100CPS Acquires Texas Retail Operation
August 23, 2016
Crop Production Services (CPS) has acquired the assets of Larry’s Chemical and Spray, Inc., for an undisclosed amount in an Read More
Key Cooperative Marcus Construction Steel Building
Retail FacilitiesMarcus Construction Builds High-Speed Agronomy Center For Key Cooperative
July 7, 2016
Key Cooperative in Grinnell, IA, wanted a state-of-the-art Agronomy Center to better serve its customers. Marcus Construction delivered exactly that. Read More
Heritage Cooperative
Retail FacilitiesKahler Automation Designs State-Of-The-Art Facility For Heritage Cooperative
July 4, 2016
Heritage Cooperative in Marysville, OH, needed an efficient liquid, dry and grain facility to serve the many needs of their Read More
The Andersons Waterloo
ManagementFirst Indiana Facility Certified Under 4R Nutrient Stewardship Certification Program
June 27, 2016
The 4R Nutrient Stewardship Certification Program has announced that The Andersons, Inc.’s Waterloo, IN, facility has been added to its Read More
Food IT
Industry NewsCalifornia Event Will Mix Ag And Tech Professionals To Explore IT Solutions
June 20, 2016
Silicon Valley is hot on agriculture, and an upcoming event in California will bring together the food and tech industries Read More
Monsanto Luling Plant
Eric SfiligojWhat’s Next For Monsanto?
May 31, 2016
For the folks at Monsanto’s headquarters in St. Louis, MO, it has been an eventful few weeks. Back on May Read More
Latest News
Soybean Field
FungicidesSyngenta Launches Interactive Tools For Vibrance Seed T…
August 30, 2016
As part of the ongoing commitment to provide growers and retailers with the most current crop protection products and agronomic Read More
EquipmentAGCO Celebrates Manufacturing In Minnesota
August 30, 2016
AGCO Corp. welcomed the I Make America campaign to its Jackson, MN, factory last Friday to celebrate the contributions of manufacturing Read More
MAGIE 2015 Overview
Eric SfiligojThe Read From MAGIE
August 29, 2016
As I write this column, I’ve just returned from the annual Midwest AG Industries Exposition (MAGIE) in Bloomington, IL. Being Read More
EquipmentAGCO Opens Nominations For 11th Annual Operator Of The …
August 29, 2016
AGCO Corp. is now accepting nominations for 2016 Operator of the Year, which recognizes hard-working applicators across the country. These Read More
CHS St. Paul, MN fertilizer terminal
CropLife 100CHS Completes $10 Million Renovation Of St. Paul Agrono…
August 29, 2016
CHS Inc., North America’s leading farmer-owned cooperative and a global energy, grains and foods company, has completed a $10 million Read More
2016 ShowStopper | Case IH Patriot 4440 Sprayer
Equipment5 Show-stopping Products On Display At 2016 MAGIE
August 26, 2016
For 10 years now, visitors to the yearly Midwest AG Industries Exposition (MAGIE) show have been tasked with voting for Read More
Crop InputsDuPont Pioneer: Corn Belt P and K Levels Lagging
August 24, 2016
A new DuPont Pioneer study conducted across 12 Corn Belt states demonstrates that growers may be leaving profit potential in Read More
Monsanto sign
Crop InputsCould a Monsanto-Bayer Union Be 2 Weeks from Fruition?
August 24, 2016
Via STLToday.com (The St. Louis Post-Dispatch): Merger talks between Monsanto Co. and Bayer AG are advancing after a series of Read More
EquipmentCase IH Debuts Nutri-Tiller 955 Strip-Till Applicator
August 24, 2016
With strip-till continuing to expand across new acres, Case IH designed the new Nutri-Tiller 955 strip-till applicator to help producers Read More
EquipmentCase Launches Aim Command FLEX, 25th Anniversary Patrio…
August 24, 2016
Case IH announces new AIM Command FLEX advanced spray technology for greater application accuracy, as well as special 25th Anniversary Read More
ASMARK 2016 Retailers Live! Tour - CPS
CropLife 100CPS Acquires Texas Retail Operation
August 23, 2016
Crop Production Services (CPS) has acquired the assets of Larry’s Chemical and Spray, Inc., for an undisclosed amount in an Read More
PrecisionAg Video Conference
Precision AgVideo: PrecisionAg Vision Conference
August 22, 2016
A Strategic Conference Focused on the Future of Farm Digitization and Precision Agriculture Visit precisionagvision.com and register today! Read More
Young Corn Plants
Industry NewsOABA Welcomes Nicole Wallace As Communication & Adm…
August 22, 2016
The Ohio AgriBusiness Association has hired Nicole Wallace as its communication and administrative coordinator. Wallace will help provide comprehensive communication Read More
Syngenta Sign
Crop InputsChemChina, Syngenta Receive Clearance From CFIUS
August 22, 2016
China National Chemical Corp. (ChemChina) and Syngenta have announced that the companies have received clearance on their proposed transaction from the Read More
ManagementAg Industry Shows and Rumors
August 18, 2016
Editors Paul Schrimpf and Eric Sfiligoj talk about the upcoming trade show schedule, crop protection merger updates, and content for Read More
MAGIE 2015
EquipmentMAGIE Takes The Pulse Of The Ag Retail Industry
August 18, 2016
Every year, one of the major highlights of my career as an ag journalist is attending the Midwest AG Industries Read More
MAGIE 2015 Overview
EquipmentPride In Professionalism On Display At MAGIE
August 18, 2016
The Illinois Fertilizer & Chemical Association (IFCA) is proud to partner with CropLife IRON and continue the tradition of bringing Read More
SprayersJenner Ag To Debut 25th Anniversary Edition Case IH Pat…
August 18, 2016
Visitors at the 2016 Midwest Ag Industries Exhibition (MAGIE) in Bloomington, IL, will have a unique photo opportunity, as Jenner Read More