Nitrogen that stays the course
Nitrogen (N) timing and placement plots are no stranger to the Farm Journal Test Plots efforts. The long-standing goal of the multiyear effort is to never let corn have a bad day, from emergence to black layer. To achieve this, it's essential to keep a tight grasp on Mother Nature as the environment sets the tone. In 2015, the plots in central Illinois experienced more than 16" of rain in June, allowing the test plots crew to monitor the in-season effects, resulting in significant yield swings.
"When we have abnormal weather during the growing season, we often learn more than in perfect growing seasons," says Farm Journal Field Agronomist Ken Ferrie. "With a wet June and July, we experienced first-hand the importance of managing N in a timely manner during the season."
Timing N is essential—not necessarily when it's applied but when the plant demands it. Ferrie recommends approaching your N program as a complete management system, meeting the needs of the crop through black layer.
Farm Site #1
In 2015, Ferrie and the test plots crew conducted a field trial in central Illinois to compare four timings of N application: pre-emergence broadcast, preplant strip-till, sidedress and late-season. While the timing and rates varied, in the end, the same amount of N was applied across the plot.
The field was leveled on April 17 using a McFarlane Incite harrow and the strip-till treatments were applied the same day using a Great Plains Nutri-Pro toolbar. With coulters 8" apart, the toolbar placed the banded N 4" on both sides of each row and 3" from the surface. The test plots crew used RTK to strip-till the N treatments for later planting. On April 29, starter was applied in-furrow across the field.
The vertical-till field is in a long-term corn-on-corn rotation. The heavy residue growing environment is important to note, in order to ensure the carbon penalty is paid on the front end. Ferrie recommends a combination of broadcast and banded N applications to weatherproof the N program.
"To pay the carbon penalty up front in a corn-on-corn rotation, allocate up to 100-lb. broadcast N or 60-lb. banded N out of your overall N program," Ferrie says.
To band nitrogen before planting, the Great Plains Nutri-Pro toolbar uses coulters to apply nitrogen 4" on both sides of the row. This toolbar was used in both Illinois and Michigan test plots locations.
Strip-till and planter-applied N, which accomplish the same goal, bypass the carbon penalty by keeping the plant happy while the microbes immobilize N to decompose residue, Ferrie explains. Those placements trigger less decomposition of surface residue and are less susceptible to nutrient tie-up.
Application timing depends on geography as well. Southern farmers who want to conserve residue should consider banded applications because they don't speed up decomposition of surface residue, Ferrie notes.
At Farm Site #1, there was a 44 bu.
increase to split-applying N and managing both the front end and back end of the crop.
In this application, 60 lb. were applied via strip-till to manage the front end and 160 lb. were applied via sidedress to finish the crop through sidedressing. This yield boost is unachievable if you only manage one versus the other. For example, in the second bar of the chart below, the corn was taken care of on the back end with 220-lb. sidedress application compared with the fifth bar where the corn was taken care of on the front end with a 220-lb. broadcast application. In this case, managing the front end resulted in a 13 bu. increase compared with only managing the back end.
The field received more than 16" of rain in June and 9" in July. This allowed for a unique look at how the various timings and placements responded during the growing season and at harvest. Check out the photos below. Early in the season, the corn responded best to the surface-rich 220-lb. N broadcast application compared with the sidedress application. The sidedress band is applied in the middle of the row, more than 15" away from the corn plant. Therefore, it takes time for the roots to reach the N and respond to the band. As evident in the later-season aerial image, the corn in the 220-lb. sidedress application is responding to the N, while the 220-lb. broadcast application is falling short.
"From emergence to thigh high, inches matter," Ferrie says. "Although we visually saw the applications flip-flop near the end, the costly impact in the spring resulted in the broadcast application outyielding the sidedress application by 13 bu."
Ferrie and the test plots crew recommend taking care of the plant on the front end and back end for optimum results. This year, the unpredictable weather provided a unique opportunity to study the effects midseason.
For example, in the 90-lb. strip-till application and 130-lb. sidedress application compared with the 90-lb. strip-till and 130-lb. late-season applications, both treatments progressed similarly until midseason. Before the late-season application, the 90-lb. strip-till application was showing signs of deficiency. With excessive rain in June and early July, the crew could not apply N until July 6. This late-season application would ideally have happened 2.5 weeks earlier, Ferrie notes. The corn did visually respond and turn green by Aug. 1, but the damage was already done.
"At this point, the late-season application could not make up for yield that was lost midseason," Ferrie says. "It is essential to pay close attention mid-season to your N levels because if not taken care of in time, the yield cannot be recovered."
Overall, at Farm Site #1, the yield results show the synergistic effect of managing the front end of the crop and pushing the sidedress rates higher to stay the course until the end of the season. The positive results to the majority of the N being applied to finish off the back end, is beneficial if applied in a timely manner.
Farm Site #2
In the sandy loam soils in Coldwater, Mich., Farm Journal Associate Field Agronomist Missy Bauer found similar yield results in her second year of N timing and placement plots. The 50-acre field compared three timings of N application: preplant strip-till, pre-emergence broadcast and sidedress N. To take care of the carbon penalty in the irrigated corn-on-corn field, 35 lb. of starter fertilizer was applied 2" to the side and 2" below the surface. The field also received three applications of N through fertigation at V10, tassel and again at R2 (brown silk) totaling 60 lb. N.
At Farm Site #2, the 30-lb. strip-till and 130-lb. sidedress applications yielded the highest at 223 bu. per acre.
This application managed both the front end and back end of corn, saving a majority of the N for the sidedress application timing.
"In the sandy loam soils, we found as long as N is taken care of up front, push the majority of N to your sidedress and late-season applications to be more efficient and help finish out the back end of the crop," Bauer says.
The chart below
shows a 28-bu. loss due to an inadequate sidedress rate that didn't provide the staying power to finish out the crop.
To help manage the front end, the southern Michigan plots determined high rates of N starters in 2x2 and low rates of broadcast or strip-till applications are important to help
combat early season N immobilization.
"The key is not to put too much N up front once the carbon penalty is paid because N on the back side is more efficient," Bauer says.
The chart below
shows a 7-bu. yield loss to not applying starter fertilizer while still taking care of the front and back end of the crop. This shows the positive effects of using high rates of N starters in 2x2 in sandy loam soils.
At a second location in Jonesville, Mich., Bauer found similar yield results studying the same three N timings and placements. This field had
30-lb. spring-applied AMS, 35-lb. starter fertilizer applied 2x2 and two shots of N through fertigation at V10 and tassel. The highest yielding application used a high sidedress rate while still managing the front end of the crop, which increased yields by 37 bu. per acre. Where sidedress rates declined, yield quickly followed.
"Overall, sidedress and late season N is a big deal in our sandy loam soils," Bauer says. "Keep in mind though, to reach optimum yield, you have to make sure you are following the crop all the way through."
Another important factor to note, is the differences in growing environments in 2015 versus 2014. In 2014, favorable weather conditions played an integral role in the success of the N timing and placement plots. At Farm Site #1 in central Illinois in 2014, the 220-bu. yield goal was surpassed by 55 bu. In 2015, the highest yield in the field was 210 bu. While still a great yield, Ferrie reminds farmers this is a clear example of why it's important to be proactive in your N program.
"Always have your ducks in a row. If the environment changes, like we experienced in 2015, you need to be ready to respond with a well-rounded N program to capture as many bushels as possible," Ferrie says.
Bauer had yield gains in 2014 ranging from 8.5 bu. to 20 bu. by managing the front end and back end of the crop. In 2015, those yield gains ranged from 28 bu. to 37 bu.
"Keep in mind looking at the past two years of results, the irrigated corn-on-corn field received late season N through fertigation yet we still saw big responses to high sidedress rates," Bauer says. "Proving from emergence to thigh high, inches matter."
To combat N deficiency and stay ahead of midseason troubles, Ferrie and Bauer recommend pulling frequent nitrate samples.
This ensures you can keep the crop progressing smoothly through each stage without running into any issues that could limit yield potential.
"Moving forward, every farmer should incorporate nitrate sampling into standard operating procedures," Ferrie says. "Designate someone in the operation, similar to your 'pest boss' to regularly test the soil."
With numerous tools available on the market to test soil and provide quick results, this process can be more seamless and convenient than it once was—if time is dedicated to do so. "You don't have to own a nitrate machine to pull frequent nitrate samples for testing, but you do need to ensure that yield crashes won't happen," Ferrie says.
Bauer plans to continue her third year of N timing and placement plots in southern Michigan this spring. Ferrie and Bauer both plan to take a deeper look into the role of late-season N as part of the overall program as well as its optimum timing and placement.
Test Plot Details
Farm Site #1
Farmers: McLaughlin Dooley farms, north of Heyworth, Ill.
Field size: 80 acres
Field specifics: Vertical till, 30" rows, corn on corn
Soil types: Catlin silt loam, Sable silty clay loam, Ipava silt loam, Osco silt loam, Dana silt loam
Planting date: April 29, 2015
Hybrid: Wyffels 7888 flex hybrid
Plant population: 34,000
Application timing and placement: Preplant strip-till (April 17), starter applied with the planter (April 29), pre-emergence broadcast (May 1), sidedress (May 21), late season (July 6)
Total nitrogen program: 251 lb.
Starter blend: 3 gal. 10-34-0 Zn Avail
Farm Site #2
Farmers: LDK Farms, Coldwater, Mich.
Field size: 50 acres
Field specifics: Vertical till, 30" rows, irrigated corn on corn
Soil types: Sandy loam
Planting date: April 30, 2015
Hybrid: Pioneer 0419
Plant population: VRT ranging 34,000 to 37,000
Application timing and placement: Preplant strip-till (April 29), starter applied with the planter (April 30), pre-emergence broadcast (May 2), sidedress (June 5)
Total nitrogen program: 255 lb.
Starter blend: 15 gal. (1/3) 10-34-0, (2/3) 28-0-0
Thank You to Our Test Plot Partners
Case IH, Jay Barth, Bill Hoeg, and CJ Parker; New Holland, Mark Hooper, Daniel Valen, Ken Paul, Mike Kizis and Sheldon Gerspacher; Burnips Equipment and Carl VanderKolk; Great Plains Manufacturing, Tom Evans and Doug Jennings; Versatile and Adam Reid; Central Illinois Ag and Kip Hoke; Kinze Manufacturing, Susanne Veatch and Phil Jennings; Schaffert Manufacturing and Paul Schaffert; Unverferth Manufacturing and Jerry Ecklund; Wells Equipment; Apache Sprayers; Trimble, Frank Fidanza and John Pointon; AirScout and Brian Sutton; GeoVantage; Ag Leader and Luke James; Yetter Manufacturing, Pat Whalen and Scott Cale; Blu-Jet and Nick Jensen; Fast and Dan Liening; GreenMark Equipment and Chad Kasprazak; LeRoy Fertilizer and Bob Spratt; Yamaha; Don Schlesinger; Lawrence "Shorty"
Olson; McLaughlin Dooley Farms; Crop-Tech Consulting, Isaac Ferrie, Brandon Myers and Eric Douglas; LDK Farms and Leon Knirk; Jerry and Peg Reed; B&M Crop Consulting, Bill Bauer, Amanda Anderson, Jared Haylett, Lauren Mezo, Abigail Wilson and Olivia Hoffman
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