Soybean Expert: Drought Impacts Soil Microbials

Severe drought conditions limited soybean production (6.2% per-acre yield decline from 2011) across much of the U.S. in 2012. The implications of the 2012 drought may progress well into the 2013 growing season. One area of concern among growers is the impact of the drought on soil microbial populations, most importantly Bradyrhizobium japonicum. Soybeans live in a symbiotic (mutually beneficial) relationship with B. japonicum. The soybean plant provides nutrients and a protective growing environment for the rhizobia, says UW-Madison Soybean Specialist Shawn Conley.

In turn, the rhizobia “fix” atmospheric nitrogen into ammonia (NH3), which can then be used by the soybean plant. For this relationship to exist and benefit the soybean plant, effective nitrogen-fixing bacteria must be present in the soil in relatively high numbers at planting time.

To date, little research has been published that quantifies the impact of soil desiccation (i.e., drought) on endemic B. japonicum populations. Researchers back in 1979 reported a biphasic decline in Rhizobium japonicum numbers in soils undergoing drying. The initial rapid phase of R. japonicum loss coincided with major water loss (simulated drought) whereas the secondary and subsequently slower decline in numbers was governed by the soil water content of specific soils. The same researchers also noted that organic matter content provided little protection against R. japonicum desiccation and loss.

In a parallel study in 1982, similar results were reported when comparing strains of R. japonicum and cowpea rhizobia under desiccation. “As one would expect, variation exists among Rhizobium species as well as individual isolates within species in their response to soil desiccation, though significant losses were evident regardless of species or isolate,” reports Conley.

To further complicate the situation, most soybean acres will be planted into corn ground that was subjected to severe drought stress. This suggests that excess nitrogen may be present for the 2013 soybean crop, Conley continues.

In excess situations soybean will generally utilize the background nitrogen prior to initiating maximum N fixation. This may lead to luxurious early season growth, which in fields with a history of white mold, may cause problems if weather conditions are conducive. High soil N reserves may also lead to increased lodging.

“In either case, manage your soybean crop accordingly to minimize risk of white mold or lodging. This can be accomplished through variety selection (i.e. white mold tolerance, short statured soybean cultivars or good lodging tolerance), decreasing seeding rates, and proper scouting to time fungicide applications if needed,” he says.

“I am not advocating that every soybean acre automatically receive an inoculant treatment, however, the small amount of research that is available on the topic does suggest that growers may expect lowered B. japonicum populations going into the 2013 growing season,” he concludes.

Topics:

Leave a Reply

Crop Inputs Stories
Crop InputsPlatform Specialty Products To Acquire Arysta LifeScience
October 20, 2014
Once the acquisition is complete, Platform Specialty Products will combine Arysta LifeScience with previously acquired companies Agriphar and Chemtura Crop Solutions. Read More
MicronutrientsMicronutrients Going Macro
September 9, 2014
Between 2014’s fantastic growing conditions and a heightened awareness on plant nutrition, the major players in micronutrients are gearing up for another big year. Read More
FertilizerFall Fertility 2014: Forecasting Fertilizer Use
September 7, 2014
Great crops this year have tapped the soil, and fall work is definitely called for, but how challenging will that get? Read More
FungicidesSudden Death Syndrome, Brown Stem Rot Reported In Indiana Soybeans
September 3, 2014
Farmers and retailers should be watching for symptoms of these two diseases over the next few weeks as they are best managed through preventative methods. Read More
Top 100 Articles
CropLife 100The Andersons Starts Venture Capital Subsidiary
January 26, 2015
The Andersons has established Maumee Ventures, a venture capital subsidiary designed to foster promising innovations that strategically align with the company’s core businesses. Read More
CropLife 100CHS Partners With Northern Partners Coop On Fertilizer Warehouse
January 21, 2015
In addition, the two companies will form a joint venture to build and operate a grain barge loading facility that will handle corn, soybeans and wheat for export through the CHS terminal at Myrtle Grove, LA. Read More
CropLife 100Wilbur-Ellis Move To Colorado Complete
January 20, 2015
Wilbur-Ellis Co. announces the opening of its new Agribusiness Division location in the Denver, CO, Metro Area. The new facility will host key personnel as the company shifts the base of its Agribusiness operations from California to Colorado. Read More
CropLife 100United Suppliers, McGregor Co., Five Others To Form Aligned Ag Distributors
January 20, 2015
These companies will continue to operate as independently owned and operated businesses, however, their crop protection divisions will now be formally aligned under the umbrella of Aligned Ag Distributors. Read More
CropLife 100Bozeman Named SEEDWAY Chief Operating Officer
January 16, 2015
He succeeds Donald Wertman, who will retire at the end of August 2015 after 40 years with the GROWMARK subsidiary. Read More
CropLife 100Wilbur-Ellis’ Craig Bair Honored For Safety Contributions To Ag Aviation
January 14, 2015
The William O. Marsh Safety Award recognizes significant achievements in safety, safety education or an outstanding operational safety program. Read More
Latest News
ManagementOABA Conference Set To Highlight Trends, Technology And…
January 29, 2015
The third annual Ohio AgriBusiness Association (OABA) Industry Conference is set to take place February 4-5. Read More
FertilizerThe Fertilizer Institute President Jahn Testifies Befor…
January 28, 2015
The committee hearing, "Freight Rail Transportation: Enhancing Safety, Efficiency, and Commerce," looked at challenges facing our nation's freight rail network created by higher demand, rules and regulations and infrastructure needs. Read More
HerbicidesPurdue University Acquires Technology For Herbicide Mol…
January 28, 2015
Protea's LAESI DP-1000 Instrument System will be used in Purdue's College of Agriculture, the Department of Botany and Plant Pathology, for the molecular imaging of herbicide active ingredients and other related compounds to optimize herbicide applications and improve weed management.  Read More
FertilizerH.J. Baker Hires New Crop Peformance Marketing Manager
January 27, 2015
As Marketing Manager for the Crop Performance division, Usman Khalid will work out of H.J. Baker’s global headquarters in Westport, CT, and will drive new initiatives for the division. Read More
CropLife 100The Andersons Starts Venture Capital Subsidiary
January 26, 2015
The Andersons has established Maumee Ventures, a venture capital subsidiary designed to foster promising innovations that strategically align with the company’s core businesses. Read More
Exclusive state-of-the art Stueve Construction designed “Vista View” Elevated Control Room.
Eric Sfiligoj2015 Agricultural Market Read: Mixed
January 26, 2015
The agricultural market could look radically different this year, profit-wise, depending upon which segment you do business in. Read More
Edward Chell Biosafe
Crop InputsBioSafe Systems Names Ed Chell California Territory Man…
January 26, 2015
BioSafe Systems has announced the recent addition of Ed Chell as California Territory Manager for the agrichemical division, supporting the crop protection, water treatment and food safety business segments. Read More
InsecticidesBayer CropScience Introduces Sivanto Insecticide
January 26, 2015
Sivanto precisely targets key damaging pests at multiple insect life stages to prevent damage to plants and help minimize the spread of diseases from insect carriers. Read More
ManagementRetail Collaboration, Communicating Agriculture’s Good …
January 23, 2015
Editors Paul Schrimpf and Eric Sfiligoj discuss the recent creation of Aligned Ag Distributors, and the US Farmers and Ranchers Read More
FertilizerOSU Expert: Toledo Water Crisis A Turning Point For Ohi…
January 23, 2015
The August 2014 water crisis in Toledo, OH, impacted Ohioans’ views of Lake Erie algae problems by increasing the attribution of blame of algae growth on agriculture. Read More
FertilizerH.J. Baker Launching TIGER XP
January 22, 2015
Tiger-Sul introduces this next generation sulphur-bentonite product with a proprietary activator – ensuring farmers have a well-balanced nutrient replacement program. Read More
Crop InputsH.J. Baker Expands China Sales Force
January 21, 2015
Global Agricultural firm H.J. Baker announced that sales veteran Shi Dongshen has joined their Shanghai office in China. This newest hire follows the recent opening of their Lianyungang Sulphur Bentonite Plant. Read More
CropLife 100CHS Partners With Northern Partners Coop On Fertilizer …
January 21, 2015
In addition, the two companies will form a joint venture to build and operate a grain barge loading facility that will handle corn, soybeans and wheat for export through the CHS terminal at Myrtle Grove, LA. Read More
Matt Hopkins5 Bold Predictions For Ag Retail In 2015
January 21, 2015
This past year was filled with ups and downs for the nation’s top ag retailers, but what will 2015 have in store? Read More
SoftwareDeere Launches App Center
January 20, 2015
The John Deere App Center provides users the ability to search and find apps most useful to their business or operations. Read More
Crop InputsNew Syngenta Herbicide Approved In Soybeans, Sunflowers
January 20, 2015
Syngenta will sell BroadAxe XC herbicide in 2015 for use on soybeans, sunflowers and dry peas Read More
CropLife 100Wilbur-Ellis Move To Colorado Complete
January 20, 2015
Wilbur-Ellis Co. announces the opening of its new Agribusiness Division location in the Denver, CO, Metro Area. The new facility will host key personnel as the company shifts the base of its Agribusiness operations from California to Colorado. Read More
Crop InputsNovozymes Sales Figures Up For 2014
January 20, 2015
Novozymes announces its sales growth in 2014 was in line with expectations as sales grew by 7% compared with 2013. Read More