Now 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 spring is unique in that in many fields the wheat crop has progressed to GS 4 and 5 in the fall and now growers need to also assessing powdery mildew at this time rather than more N to induce tillering as many fields are extremely progressed and additional N now might create more issues. This article will detail some points to consider that may help with management decisions.
Spring tiller assessment is the first item to check in the field. Without having to do a miriad of calculations here is a simple method. 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 plants per square foot). To determine the amount your stand has once you count the total tillers found in the linear 3 foot stick calculate the tiller count per square foot by taking total tillers multiplied by 4 and then divided by the row width in inches. The new number represents tillers per square foot. For example if you checked 5 areas in a field and the average tiller count you find is 60 tillers then you would take 60 times 4 (240) then divided by the row width(7inch) to arrive at a total of 35 tillers per square foot. Since the goal is to have 70 -100 tillers and this is far below minimum, Nitrogen will be needed to stimulate more tillering.
A second way is to count the plants and use the table to provide guidance. This guide converts sq foot to different linear feet by varying row spacings.
Row Spacing Table.
In marginal fields wheat will respond to nitrogen applied at this time to promote tillering. In no till 40-60lbs of actual N/acre will be adequate to promote tiller development. Most of the wheat grown in our area has a straw market available and with the removal of straw comes the removal of phosphorus and potassium. Wheat removes 1lb of P205 and 1.8lbs of K20 per bushel of harvest. That is a large amount of nutrient taken from the soil reserves. I was in fields last year that double crop soybean crop planted after wheat showed potash defiency due to low levels in the soil. My point here is that unless the soil test is above optimum P and K removal rates should be satisfied through fertilizer or manure sources.
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, may hamper tiller formation 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 tiller development. If this is the case then do not apply any herbicide unless absolutely necessary.
|Seeds or plants per sq. ft||Seeds or plants (millions/acre)||Plants or seeds per foot|
|6 inches||7 inches||7.5 inches||8 inches||10 inches|