Winter wheat emergence improves
By Noel Mues
University of Nebraska-Lincoln Extension
As reported by the Nebraska Ag Statistics Service, while winter wheat emergence improved from 74 percent last week to 83 percent this week, it still lagged behind the long-term average of 99 percent by this date. Winter wheat condition was much below average at 19 percent very poor, 30 percent poor, 38 percent fair, 13 percent good to excellent, well below the average of 69 percent good to excellent.
Dryland wheat emergence in our area of the state is probably less than 50 percent and delayed emergence caused by lack of soil moisture is cause for all sorts of problems for next year's wheat crop.
Delayed seeding date and/or poor growing conditions, for whatever reason, prevents or delays root growth to the dual placement fertilizer band. Poor root growth limits root fertilizer contact and tillering, which affects yield.
For optimum yield winter wheat should be well tillered in the fall. Much of the grain yield of winter wheat occurs on tillers that develop from buds in the axils of lower leaves. Under normal conditions, as much as 70 percent of the grain yield comes from tillers. Tillering also enables the plant to adapt to different conditions. Few tillers develop when moisture, nutrition, and other conditions are poor, whereas numerous tillers that increase the yield potential form when conditions are favorable.
Seeding date greatly affects development of tillers in winter wheat. Seeding during the optimum period enables wheat to form sufficient but not excessive tillers. Early seeding results in too many fall tillers, which may compete with each other, become diseased, and deplete soil moisture so that grain yields are low. Late seeding gives plants little time to develop tillers, resulting in an inadequate numbers of spikes (heads) for high yields the following spring.
Senescence (biological aging of plants) and death might eliminate excessive tillers that form during the fall. Conversely, if too few tillers develop during fall, additional tillers may form during spring; however, the yield potential is greater for tillers that develop during fall than those that develop during spring.