Nitrogen Management Decisions Finalized in 2023 Competitions
August saw the conclusion of the nitrogen management decisions for the TAPS competitions. For the second year, participants in the sprinkler and SDI corn competitions had the option to fertigate five times, whereas the new popcorn competition had three fertigation opportunities. All competitions, including sorghum at the Stumpf International Wheat Center in Grant, Nebraska, had pre-plant and side-dress options.
Below is a look at the nitrogen (N) decisions made in each competition and some conclusions derived from the decisions.
Sprinkler Irrigated Corn Competition
Among the 28 competing sprinkler corn teams, none chose to manage their nitrogen (N) fertilizer the same. The total N applied ranged from 90 to 300 lbs/acre with the average being 189.5 lbs/ac, excluding the control, which received no N fertilizer. Only eight teams chose to forgo applying a portion of their N fertilizer as pre-plant and five teams chose not to apply N during the side-dress application, including one that refrained from pre-plant also. Four teams chose to only apply their N during pre-plant and side-dress operations (i.e., did not apply via fertigation). The remaining 33 teams utilized at least two of the five fertigation options.
The unfortunate hail event that took place July 22 made a number of participants revise their N management plan for the final two fertigation opportunities. Eleven teams applied N at the fourth fertigation and only six teams took advantage of the fifth fertigation opportunity. Only three teams chose to apply N at each of the seven opportunities, including pre-plant, side dress and five fertigations.
On July 17 and at the VT growth stage, leaf tissue samples were collected and submitted to Ward Laboratories in Kearney, Nebraska, to determine N sufficiency. Participants were provided this information prior to the last two fertigation opportunities. Six teams had values over 3.42%, which is considered high, with the rest of the teams falling in the sufficient category.
SDI Corn Competition
The seasonal N fertilizer decisions submitted in the SDI corn competition ranged from 140 to 260 lbs/ac, excluding the control farm, which received no N fertilizer. The average for the 15 competing farms was 192.7 lbs/ac. Five teams chose to forgo pre-plant and six chose to forgo side-dress. Whereas one team chose to apply their total N at pre-plant and one team chose to only apply N at pre-plant and side-dress. The remaining teams all chose to use at least three fertigation opportunities, with one of those choosing to just apply N via fertigation.
Unlike the sprinkler corn participants, the hail event on July 22 only resulted in a few participants revising their N management plan for the final two fertigation opportunities. Nine teams applied N at the fourth fertigation and nine teams took advantage of the fifth fertigation opportunity. Three teams chose to apply N using all seven application times.
Similar to the sprinkler corn competition, leaf tissue samples were collected on July 17. Participants were provided this information prior to the last two fertigation opportunities. Only three teams had values over 3.42% considered high, while the others all fell in the sufficient range.
Popcorn Competition
The seasonal N fertilizer decisions submitted in the first year of the popcorn competition ranged from 50 to 225 lbs/ac, excluding the control plot, which received no N fertilizer. The average for the 12 competing farms was 135.4 lbs/ac. Only one team chose to forgo pre-plant and one chose to forgo side-dress. All but two of the teams chose to take advantage of at least one of the three fertigation opportunities. Eight of the 12 competing teams chose to apply N during the two fertigation options following the hail event on July 22. Only three teams chose to apply nitrogen using all five N application opportunities.
Unfortunately, leaf tissue sampling for percent N was not performed due to the hail damage.
Sorghum Competition
Participants in the sorghum competition were required to decide on their N for both irrigated and dryland sorghum. Participants had the option to apply N as pre-plant and side-dress applications, since fertigation was not available.
In the dryland sorghum, the seasonal N fertilizer decisions ranged from 0 to 125 lbs/ac, excluding the control, which received no N fertilizer. Even with just two nitrogen application options, none of the teams chose to apply their N in the same manner, although a few teams applied the same total amount. Seven teams chose not to apply N during the pre-plant opportunity, four chose not to apply N via side-dress and seven teams applied N at both opportunities. The average N amount applied, excluding the control, was 70 lbs/ac.
As for the irrigated sorghum, competitors’ N fertilizer decisions ranged from 0 to 200 lbs/ac. Here again, none of the teams chose to apply their N in the same manner, although a few teams applied the same total amount. Five teams chose not to apply N during the pre-plant opportunity, four chose not to apply N via side-dress and nine that applied N at both opportunities. The average N amount applied was 100 lbs/ac, excluding the control.
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