Objective

The purpose of this study was to determine fertilizer rate and timing on yield and quality of spring wheat.

Summary

This study was laid out in a randomized complete block design with three replications. The Nitrogen (N) treatment was the main plot. The five elite spring varieties were the subplot. Management information for this study is presented in Table 1.

Results of this two-year study showed a significant yield difference with N application regardless of timing (Figure 1) in relation with the control. Higher yield was obtained with a total N application of 150 and 200 lb/a (residual + applied N) compared to control (residual N).

Fertilizing N increased grain protein. In particular, the spilt-application treatment ‘75p + 75h’ consistently had the highest grain protein across years and is optimal. In general, falling number increased with N application relative to the control (Figure 3), except ‘75p + 75h’ treatment.

The yield, yield component, and quality of the five elite varieties are presented in Table 2. Among the five elite varieties, Vida  obtained the highest grain yield, Egan the highest grain protein content and  Dagmar showed the highest test weight and thousand seed weight.

Table 1. Management Information

Seeding date:

4/18/2025 (108 Julian)

Field Location:

R6

Seeding rate:

26 Seeds/ft2

Harvest date:

8/11/2025 (223 Julian)

Previous crop:

Canola

Soil type:

Creston silt loam

Herbicide:

Axial Bold 

Cleansweep 

Tillage:

Conventional

Soil residual nutrient

(N, P, K lb/A):

66-8-140 (Fall 2024)

Insecticide:

N/A

Nutrient fertilizer applied (N, P, K lb/A):

Various by TRT

Fungicide:

N/A

 

Table 2. Yield, Yield Component, and Quality of Spring Wheat in Response to Different Nitrogen Rates and Timing

Yield, yield component, and quality

Variety

Dagmar

Egan

MT Carlson

MT Ubet

Vida

Grain yield (bu/a)

64.5c

61.4d

67.9b

65.1c

73.9a

Grain protein content (%)

15.6b

16.9a

14.8d

14.9c

14.9cd

Test weight (lb/bu)

61.1a

59.4d

59.6d

59.9c

60.8b

1000 seed weight (g)

47.0a

41.3e

45.3b

43.6d

44.4c

Falling number (seconds)

394c

539a

396c

471b

346d

Note: The same letter assignment denotes non-significance at α=0.05.

 

Figure 1. Yield response with N application timing. Actual applied N fertilizer is shown in x-axis by year.

Figure 1. Yield response with N application timing. Actual applied N fertilizer is shown in x-axis by year. The same letter assignment denotes an insignificant difference at α =0.05 within year.

 

Figure 2. Grain protein concentration with N application timing.

Figure 2. Grain protein concentration with N application timing. The same letter assignment denotes an insignificant difference at α =0.05 within year.

 

Figure 3. Falling number with N application timing.

Figure 3. Falling number with N application timing. The same letter assignment denotes an insignificant difference at α =0.05 within year.

Acknowledgements

We thank farm operations staff J. Penney and A. Goodman, without whom this research would not have been successful. We also acknowledge T. Burkhart, J. Cain, A. Mathison, and E. Schreifels for their assistance with field operations, data collection, and sample processing. This study was supported by the Montana Fertilizer Advisory Committee (MFAC).

Link to 2025 Conventional and Split-Application Nitrogen Rate Performance in Elite Spring Wheat Varieties Printable Report (PDF)