Nitrogen management opportunities concluded with the last fertigation being completed on the corn competition plots on Aug. 11. Nitrogen management is the fourth of six management decisions to be finalized in the corn competitions, with only irrigation and marketing left to round out the 2021 TAPS contests. The nitrogen decisions will take a leading role in identifying this year’s efficiency and profitability winners. Below is a look at the nitrogen (N) decisions made in each competition and some conclusions derived from the decisions and how they were submitted.

Sprinkler Irrigated Corn Competition

Among the 30 teams in the sprinkler corn competition, only two teams were identical in how they managed their N fertilizer. The total N applied ranged from 120 to 290 lbs/acre, excluding the control plot which received no N fertilizer. All but three teams chose to apply a portion of their N fertilizer as pre-plant. Nearly a third of the teams chose not to apply N during the side-dress application. All teams except one utilized at least one of the four fertigation options.

On July 20, 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 their final fertigation opportunity. Only two teams had values over 3.42%, which is considered high, but neither of these teams chose to modify their previous N decisions.

Thirteen teams submitted their N management plan at the beginning of the season and didn’t modify it throughout the year. Only one of the competitor teams submitted each N management individually throughout the season.

SDI Corn Competition

The seasonal N fertilizer decisions submitted in the SDI corn competition ranged from 120 to 260 lbs/ac. One team chose to not have any nitrogen applied throughout the season. Four teams chose to forgo pre-plant, seven chose to forgo side-dress, but all teams chose to apply a portion of their N fertilizer via fertigation. One team chose to just apply N through fertigation opportunities.

Five of the teams submitted all of the N management decisions at the beginning of the year with no modifications throughout the season. Not a single competing SDI team submitted their decisions individually throughout the season.

Sorghum Competition

With the change in the sorghum competition this year, participants were able to decide on their N for both irrigated and dryland sorghum. These decisions are interesting to analyze, not just for each individual field but also what each competitor did across the two fields. Participants were only given the option to apply N as pre-plant and side dress applications.

In the dryland sorghum, the 16 teams seasonal N fertilizer decisions ranged from 33 to 180 lbs/ac. Only two teams chose to apply their N in the same manner, although five chose the same total amount (110 lbs/ac). All teams chose to apply N during the pre-plant opportunity, but only 12 chose to apply N via side-dress. The average N amount applied, excluding the control, was 108 lbs/ac.

As for the irrigated sorghum, competitors N fertilizer decisions ranged from 45 to 260 lbs/ac, a range of 215 lbs/ac (See Chart 4). None of the teams chose to apply their N in the same manner. All teams chose to apply N as a pre-plant operation, and all but one team chose to follow with a side-dress application. The average N amount applied was 150 lbs/ac excluding the control.

Only one team chose the same N application method for both their dryland and irrigated sorghum.