Once the snow recedes is the time to assess small grain stands; determine whether an early topdress is required and to assess the status of some early season pests. This article will detail some points to consider that may help with management decisions.
Tillering Assessment: Spring tillering assessment is the first item to check in the field. The method can be the same as described in last month’s article for assessing plant numbers. To do this you will need a 3 foot measuring stick. Walk the field in numerous locations and drop the stick on the ground near the base of the plants and count the total number of tillers. Average the sites you check to arrive at an average tillers per three feet. The goal is to have 70–100 tillers per square foot (25–35 plants per square foot). To determine the number of tillers per square foot, calculate the average number of tillers found in the all the 3 foot measurements made, multiply by 4 and then divided by the row width in inches. This number represents tillers per square foot. For example if you checked 5 areas in a field and the average tiller count/ 3ft is 60 tillers, then you would take 60 times 4 (240) then divided by the row width(ex.7inches) to arrive at a total of 35 tillers per square foot. Since the goal is to have 70–100 tillers, this is far below the minimum. Nitrogen will be needed to stimulate more tillering and fields in this condition should be topdressed first. If you would like more detail there is a video at the CMEG Web site.
Topdress Decisions: Except to stimulate tillering, from the standpoint of crop need there is no need to top-dress N before green up. But top-dressing should be completed by the time the first node on the stem can be seen or N demand may not be met. Most wheat in our area provides straw and with the removal of straw comes the removal of phosphorus and potassium. Wheat removes 1.0 lb of P205 and 1.8 lbs of K20 per bushel of harvest. Last year, in some fields that double crop soybean crop were planted after wheat, potash deficiency showed up in the soybeans due to low levels in the soil. The point here is that unless the soil test is above optimum, compensate for P and K removal through fertilizer or manure sources.
Pest Considerations: This time of year, most pests like insects and disease are not active. However, weeds may be of concern depending on the number of weeds and there growth relative to the wheat. Weeds that encroach can hamper tillering and compete for nutrients. As you scout the wheat stands and determine the need to apply a herbicide for control, be sure to check the plants crown location. If roots are exposed from heaving or from improper planting depth, the herbicide may cause injury to the plants which will limit tillering. If this is the case then do not apply any herbicide unless absolutely necessary.