Evaluating Winter Wheat Stands

By Mike Rankin

Our cold March weather doesn’t exactly have the winter wheat crop sprinting out of the blocks. Nevertheless, we have to assume the time is near when fields will begin turning from brown to green. When this occurs, the spring ritual of walking wheat fields and assessing stand condition will occur.

The first order of business is to make an accurate stand count. This can sometimes be more difficult than it might initially seem. Most importantly, wait long enough for plants to green-up and sustain growth. Initial growth may vary across the field because of topography and snow cover. What may initially look dead may just be bit delayed.

To make stand counts, use a yard stick and count the number plants along the 3-foot distance. Repeat the procedure at several randomly selected areas in the field. Next, determine the average number of plants per 3-foot of row by averaging your results over the field locations where counts were made. Multiply this number by 4 and then divide by the row width (inches) to determine the number of plants per square foot. For example, in a 7-inch row spacing if the average number of plants per 3-foot of row length is 42, then:     42 x 4 / 7 = 24 plants per square foot

A word of caution when making stand counts:  be sure you are counting plants and not tillers. Often there can be several tillers per plant. Any field with an average stand count of less than 12 to 15 plants per square foot is probably not worth keeping.

Once a decision is made as to whether a stand is a keeper or not, the next determination centers on when to make an application of nitrogen. Nitrogen serves two roles: 1) provides plant nutrition, and 2) increases tiller number.

There is some efficiency advantage to applying nitrogen just before the jointing stage rather than early green-up. However, to employ this strategy an evaluation of tiller number must be made. Research indicates that if tiller number is below 70 per square foot, nitrogen needs to be applied early to stimulate additional tillers and ultimately the number of grain heads. If there are over 70 tillers per square foot, it may be beneficial to delay nitrogen applications until just prior to the point when stems elongate.

Source : uwex.edu