Chance to Grow More Tillers
With what little wheat that was planted due to the wet year that many areas experienced and delayed harvest due to the wet conditions, late January to early-mid February is the time to determine if the crop has enough tillers to optimize yield. This is a very important decision in regards to wheat production. Apply nitrogen in late January or February only if tiller densities are less than 50 tillers per square foot. If nitrogen is not needed and an application is made in January or February can result in increased risk of freeze damage, disease, lodging, and reduced yield. If tillering is low; however, an early application of N can help to stimulate further tiller development in the last few weeks before growth stage 30, resulting in higher yield and profit. The calendar date when wheat reaches growth stage 30 is influenced by variety, planting date, and environmental conditions. Early heading varieties can reach it in February. Late heading varieties may not reach growth stage 30 until mid-March. The following guidelines will help you decide whether to apply nitrogen in late January or early February.
If at the end of January or in the first week of February, wheat looks fully matted, then it is well on the way to being a potentially high yielding field. This wheat has about 100 well-developed tillers per square foot and should not have any nitrogen applied until growth stage 30. A well-developed tiller or stem is one with at least three leaves. Wheat with a “medium” density stand with about 50 tillers per square foot, is also is well on the way to being a good yielding crop, and should not have any nitrogen applied until growth stage 30. If wheat has poor tiller development and only has about 20 tillers per square foot, then it has a low yield potential and needs more tillers to develop in February. It should have 50 to 70 pounds of nitrogen fertilizer applied in late January or early February. A second nitrogen application should be made to finish this crop off at growth stage 30. Thin stands need timely weed management, but should not have 2,4-D applied because 2,4-D may inhibit tiller development. Growers also need to scout for cereal leaf beetle in April, as these insect pests are often attracted to thin wheat stands.
Wheat stands that are thicker but not as well developed may also need an early nitrogen application. Such a field will yield best with 40 to 50 pounds of nitrogen fertilizer applied in late January or early February.
To determine tiller density, count all the tillers or stems that have at least three leaves in a foot of row. Do this in several places and take an average. Tiller density is then computed as follows:
Tillers per square foot =
(tillers per foot of row) X 12
(row width in inches)