Calculator Helps With Soybean Seeding-Rate Decisions

With less costly soybean seed and the wide range of which soybean plant populations produce similar yields, soybean seeding rates have not historically been as closely calculated as those for corn. But soybean seed costs have risen to the point at which farmers don’t want to plant more seeds than they need for top yields, according to University of Illinois crop sciences professor Emerson Nafziger.

“Although we often don’t see this, it’s possible in some cases that high soybean plant populations might increase lodging or stress, and actually result in lower yields, especially in wider rows, where plants are closer together,” he added.

With yields usually maximized at 80,000 to 100,000 plants per acre, Nafziger suggests aiming to establish 100,000 to 120,000 plants, which allows for lower- than-expected emergence.

Nafziger said that decreased pod set due to stress in 2012 means that seed this year tends to be larger than normal. This can sometimes mean more stress cracks or mechanical damage, but germination percentages are generally reported to be good and it appears that seed quality isn’t much of an issue.

“Even with good seed germination, we often find soybean seeds establishing plants at lower percentages than we see with corn,” Nafziger said. “This is in part due to lower standard (warm) germination percentages and partly to the fact that soybean seeds, which need to stay healthy long enough to drag the large cotyledons up and out of the soil, often struggle to emerge, especially if conditions are wetter or cooler than normal, or if soils form a crust after planting.

“To help make seeding rate decisions for soybean, Dennis Bowman and I developed a seeding rate calculator — or rather, we resuscitated one that we had running some years ago,” Nafziger said.

The calculator asks for either weight and seeds per pound for seed units sold by weight, or for seeds per unit for seed sold by number. It then asks for the percentage of warm germination, which is required to be on the seed tag or container, and for the cost per unit. Field size and row spacing are also requested.

The only subjective information requested by the calculator is an estimate of the percentage of germinable seed expected to emerge and establish plants under the soil conditions and perhaps the weather forecast at planting.

Nafziger said that under very good conditions it is reasonable to expect close to 100% of good seed to emerge. But if soils are cold or wet (or likely to get wet), this percentage should be decreased. The calculator goes from 100-70%, with the idea that expecting less than 70% emergence of good seed should be a signal to wait for better conditions before planting.

“The calculator returns seed spacing down the row, seed requirements per acre and for the field, and the amount of time it will take to plant the field,” Nafziger said. “While we developed the calculator for soybean, it works for corn or small-grain seed as well.”

The Web-based PC version is available at ow.ly/ko8gL, the Android app is at ow.ly/ko8sm, and the iPhone/iPad online spreadsheet is at ow.ly/ko8au.

Leave a Reply

Precision Ag Stories

Precision AgGoogle Glass: New Tool For Ag
October 8, 2014
New wearable smart technologies such as Google Glass show potential to greatly impact how we accomplish the business of feeding the world. Read More
Precision AgPrecision Agriculture: Finding The Payback
September 6, 2014
Profitability in precision ag is not about any one technology, but the result of employing technology in a total system approach that is agronomically sound. Read More
Precision AgUAS: The S Stands For Smart, Service And Sensors
May 1, 2014
The only thing occuring more rapidly than the technologies’ evolution is the clamoring to implement UAS into agriculture as soon as possible. Read More
Precision AgAg Retail: 3 Tech Trends To Watch In 2014
April 1, 2014
It's been a busy first quarter of technology developments in 2014. Here are some of the highlights, and things to watch in the months ahead. Read More

Trending Articles

CropLife 100Agrium To Cut 500 Jobs, Sell Some Businesses
November 11, 2014
Among the businesses Agrium will try to sell are its micronutrients and European UAN (urea-ammonium nitrate) lines. Read More
HerbicidesMonsanto, Sumitomo Chemical And Valent Extend Crop Protection Collaboration
November 10, 2014
The agreement extends their strategic partnership in Monsanto’s Roundup Ready PLUS Crop Management Solutions platform for soybeans and cotton in the U.S. Read More
FertilizerCorn Rootworm Hybrids And Potassium Uptake
November 4, 2014
To achieve successful yields, grower-customers can’t afford to cut back on their potassium use with corn rootworm hybrids, say experts. Read More
StewardshipResponsibleAg Begins Auditor Training
October 31, 2014
ResponsibleAg auditor training is now underway at the Ford B. West Center for Responsible Agriculture in Owensboro, KY. Read More
InsecticidesNew Research Study Shows The Value Of Neonics
October 29, 2014
The study evaluated seed treatment, soil and foliar uses of neonicotinoid insecticides in the U.S. and Canada. Read More
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

Latest News

EquipmentAGCO Announces Operator Of The Year Finalists
November 20, 2014
Four custom applicators have been selected by AGCO Application Equipment as finalists for 2014 Operator of the Year, an honor that recognizes them as being among the top professionals in their industry throughout North America. Read More
MicronutrientsH.J. Baker Expands Tiger-Sul Business
November 20, 2014
H.J. Baker has created and filled two strategic positions in business development and sales within its Crop Performance Division. Read More
soybean field
FertilizerGeneral Mills Honors United Suppliers For Nitrogen Opti…
November 19, 2014
United Suppliers winning proposal detailed SUSTAIN, a consulting network that provides customized products and services for farmers using a needs-based system approach. Read More
EmployeesOhio AgriBusiness Association Awards $25,000 In Scholar…
November 19, 2014
Each year, the Ohio AgriBusiness Association Educational Trust scholarship program awards scholarship dollars to students enrolled in an agriculture-related field attending several state colleges. Read More
ManagementServi-Tech Names New CEO
November 17, 2014
Servi-Tech has named Greg Ruehle its new president and CEO. Read More
CropLife 100Pinnacle Ag Acquires Colorado Aerial Application Outlet
November 17, 2014
Ft. Lupton, CO-based Reck Aviation — a full-service chemical application company providing aerial crop applications of fertilizers and crop protection products — will operate as part of Pinnacle's AgOne Application Services brand. Read More
Eric SfiligojMcDonald’s Message: Biotech Crops Scarier Than Cancer
November 17, 2014
Despite their potential health benefits, one of the world’s largest potato users will pass on a new biotech offering. Read More
MicronutrientsWinField Releases 2014 NutriSolutions Results
November 14, 2014
A number of significant regional and national crop deficiency trends emerged from the 2014 WinField NutriSolutions tissue sampling program. Read More
FertilizerH.J. Baker Opens Chinese Production Lines
November 14, 2014
The occasion was the official launch of the Tiger-Sul sulphur Bentonite production line of two much anticipated fertilizer products in China, T90CR sulphur fertilizer and TZinc micronutrient enhanced sulphur fertilizer. Read More
ManagementOhio Certified Crop Adviser Program Accepting Nominatio…
November 14, 2014
The award recognizes an individual who delivers exceptional customer service for farmer clients in nutrient management, soil and water management, integrated pest management and crop production in Ohio. Read More
HerbicidesSyngenta Announces Acuron Trial Plot Results
November 14, 2014
Acuron was tested at 167 trial locations across 35 states. Trials included 95 Syngenta locations, 54 university locations and 18 distributor locations. Read More
Crop InputsVerdesian Expands Sales Force
November 13, 2014
The new sales representatives will work with growers, retail partners and distributors to oversee technical training and product education. Read More
EquipmentAGCO Raises $100K For Wounded Warrior Project
November 13, 2014
AGCO Corp. partnered with local AGCO dealers across the U.S. and Canada to raise nearly $100,000 in support of wounded service veterans. Read More
HerbicidesDow AgroSciences Announces Launch Of Enlist Duo Herbici…
November 12, 2014
It will be launched in conjunction with a stewarded introduction of Enlist corn, and seed production of Enlist soybeans in 2015. Read More
FertilizerH.J. Baker Expands Tiger-Sul Business
November 12, 2014
Agricultural firm H.J. Baker has created and filled two strategic positions in business development and sales within its Crop Performance Division. Read More
Blenders13 Fertilizer Blenders For 2015
November 12, 2014
Dealers can find a fertilizer blender to deliver any speed, volume and custom mix they want. Read More
CropLife 100Wilbur-Ellis Vice President Receives Honorary FFA Award
November 11, 2014
Jim Loar, vice president of operations of Wilbur-Ellis’ Agribusiness Division, was awarded the Honorary American FFA Degree at the 2014 National FFA Convention and Expo in Louisville, KY. Read More
FertilizerBASF Makes Limus Nitrogen Management Available In U.S.
November 11, 2014
Reducing ammonia losses by more than 90%, Limus nitrogen management has demonstrated increased crop yields on average of 6%, according to 2013 replicated research. Read More