Del Voight – Senior Extension Agent- Penn State Extension – Crop Management Team.
The question right now is how late is too late to put additional N on wheat? How Much?
Wheat takes much of its N up after GS 6. Most N is then assimilated somewhere shortly after heading or GS 10. As long as the N that goes on is available immediately such as in the nitrate form or a form that quickly changes in the soil it will assist in maintaining yields.
How much depends on alot of factors. The growers I talked to had put 100 lbs on at planting. If we assume a 25% loss of the N due to leaching then perhaps an additional 25 units of N would need to be applied prior to GS 10.
Talking to another grower who has not applied any N to date then perhaps a full shot of the N is required. To lower the yield expectation might be prudent particularly if the wheat is yellow in appearance. There fore if one expects 80 bu/acre an additional 80 lbs of N should be considered. As far as form since there is sensitive tissue on the plants now I would recommend a dry formulation that would avoid any hindering of the plant leaves ability to absorb sunshine. This is of great importance with the flag leaf showing.
