Objective:
To evaluate the performance of the split-application of nitrogen in a rainfed winter wheat environment in northwestern Montana
Personnel:
J.A. Torrion, Eeusha Nafi, Daniel Porter
Summary:
The off-station winter wheat nitrogen (N) trial was planted under no-till rainfed ground with row-spacing 12-in apart on Sept. 22, 2020. There were six different nitrogen application treatments for this trial. The nitrogen rates applied were: 1) 0 as control, 2) 40, 3) 80, 4) 80 but were split-applied, 5) 120, and 6) 120 but were split-applied lbs N/A. Urea was used as an N fertilizer source. The soil had a 52 lbs/A residual nitrate and 10 lbs N drilled with the seeds at planting.
Grain yield linearly increased from no N application until 80 lbs/A, then plateaued afterward. No significant yield differences were recorded between 80 lbs/A and 120 lbs/A N applications in either N-applied in early spring or split (early spring + heading) treatments. The grain protein increased up to the split 80 lbs/A N application (Figure 2). The spring-applied 80 lbs/A N had an inferior grain protein compared with the split 80 lbs/A N application (40 lbs in spring & 40 lbs at heading). Increasing N application to 120 lbs/A (split or not) did not show a significant protein increase in reference to the split 80 lbs/A N application. The plant height, test weights, and the falling number increased at 80 lbs/A N application (for both spring and split application) then plateaued after that (data not presented).
In 2021, this nursery received 9.7 inches of rain.
Table 1. Management Information |
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| Seeding date: | 9/22/2020 | Field Location: | R13 |
| Julian date: | 266 | Harvest date: | 8/12/2021 |
| Seeding rate: | 130 lbs/A | Julian date: | 224 |
| Previous crop: | Barley | Soil type: | Creston Silt Loam |
| Herbicide: | 5/6: CleansweepM | Tillage: | No-till |
| Insecticide: | None | Variety: | FourZeroSix |
| Fungicide: | 6/11: Headline | Soil residual nutrient (NO3-, P, K lb/A): | 52-28-604 |
| Nutrient fertilizer applied (N, P2O5, K2O lb/A): | 10-35-45 (10 S, 1 Zn) Fall-drilled N applied varied, see N treatment | ||
Figure 1. Yield response to nitrogen (N) application rates and timing (split-applied at heading). The first application was in early spring. The split (second) application is indicated by a ‘+’ sign and H (at Heading). The application rate treatments specified did not include the residual N (52 lbs/A) and the amount drilled with the seeds (10 lbs/A). The same letter assignment indicates nonsignificance at α= 0.05.
Figure 2. Grain protein response to nitrogen (N) application rates and timing (split-applied at heading). The first application was in early spring. The split (second) application is indicated by a ‘+’ sign and H (at Heading). The application rate treatments specified did not include the residual N (52 lbs/A) and the amount drilled with the seeds (10 lbs/A). The same letter assignment indicates nonsignificance at α= 0.05.