Response of Deltapine® Brand Cotton Products to Nitrogen Application Rate

January 13, 2025

TRIAL OBJECTIVE

  • Nitrogen (N) fertility is a very important factor to balance in cotton production systems and questions about N fertilizer management arise as new cotton varieties are introduced into the marketplace.
  • Inadequate N can lower yield potential, while excessive N can lead to excessive vegetative growth, also lowering yield potential and possibly requiring additional plant growth regulator (PGR) management.
  • Heavy clay soils often need higher N rates due to the reduced availability of applied fertilizers.
  • This study attempts to provide growers with information for the fertility decision making process.

RESEARCH SITE DETAILS

Site details

  • Four N application rates were tested in this demonstration. All treatments were applied as 30-0-0-2.5 and all rates are actual lb N applied per acre.
    • 80 lb N/acre
    • 120 lb N/acre
    • 160 lb N/acre
    • 200 lb N/acre

Table 1. Deltapine® brand cotton varieties planted in this trial.

  • All varieties were planted as strip plots with no replications at 44,000 seeds per acre and establishment was approximately 80% across the trial.
  • Plots were 12 rows wide and 1,000 feet long, for approximately 1 acre per plot.
  • PGR was applied as needed based on scouting and measured plant growth rates.
    • Three applications were required at typical timings and rates.
    • This production system did not develop huge excess vegetative growth potential due to growing conditions in the 2024 season. Growth potential would be characterized as moderate.
  • All field work, tillage, and herbicides were applied per local standards.
  • Yield data were collected using commercial harvest equipment and representative site turnout was used when calculating yields.

UNDERSTANDING THE RESULTS

Figure 1. Average yield response of all cotton products tested across nitrogen application rates.
Figure 1. Average yield response of all cotton products tested across nitrogen application rates.

Figure 2. Yield response of the seven tested Deltapine® brand cotton products to different nitrogen application rates.
Figure 2. Yield response of the seven tested Deltapine® brand cotton products to different nitrogen application rates

  • When averaged across all varieties test, the highest yield in this trial occurred at N rates of 120 lb N/acre.
  • The 120 lb N/acre application also produced the highest yield in three of the tested cotton varieties: DP 2211 B3TXF (1,276 lb lint/acre), DP 2333 B3FX (1,286 lb lint/acre), and DP 2328 B3TXF (1,207 lb lint/acre). These were the two highest yields observed in the trial and the sixth highest yield, respectively.
  • Some additional vegetative growth was observed in higher N rates, but those treatments did not require additional PGR applications in this case.
  • This demonstrates the excellent potential of recently introduced Deltapine® cotton genetics coupled with the latest trait technology in ThryvOn® cotton.

KEY LEARNINGS

  • Typical rates of N used in cotton production range from 80 lb N/acre to 150 lb N/acre. Based on the data from this study, this range appears to be adequate for the yield levels measured during 2024.
  • Many factors can contribute to the need to change N rates including:
    • Cotton on cotton production systems – Typically requires an increase in N rates.
    • Cotton on corn production systems – Typically a decrease in N rates.
    • Cotton planted on heavier soils – Typically an increase in N rates.
    • Cotton on sandier/stronger soils – Typically a decrease in N rates.
    • Cotton on thinner/weaker soils – Typically an increase in N rates.
  • Several of the above factors can be interactive and influence the need for changes in N rates.
  • Growers should carefully consider all the above factors when selecting N rates for any production system to help avoid excess vegetative growth as a side effect of higher N rates.
  • Alterations in PGR use may be required in some systems. Awareness, scouting, and prompt action are essential to developing an optimized production system.
  • Please contact your local Bayer/Deltapine® representative for more information.

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