|Green and Growing|
|Written by D. Bruce Bosley, CSU Extension Agent/Cropping Systems|
To replant or not to replant is the question that many wheat producers are now pondering. Nearly all wheat-growing areas in Colorado have poor, patchy wheat stands.
The dry fall and winter have kept wheat seed in some field areas from germinating and establishing a viable wheat sprout or allowed germinating wheat to dry out before becoming established. Now dryland wheat farmers are considering their replanting options for spots and entire fields.
Determining whether a field has an adequate stand in late winter is not always straight-forward. Winter wind and freeze injury can make wheat plants look dead or non-existent. However, upon close inspection, these plants are often found to be viable.
I took the opportunity to look at four wheat fields on Monday, Feb. 28. One in particular looked very bare. However, on closer inspection, an adequate plant stand had been there at between six and 10 plants per linear foot of row.
Furthermore, those I dug had viable crowns and green tissue to the soil line. The surface leaves had been damaged and mostly removed by wind, frost and sun-scald. I strongly suspect that these plants will probably recover and still produce reasonably well.
I’ve had wheat test plots that had little ground cover and had gotten beat up through the winter in a similar manner. One plot in particular, after getting sever winter damage, recovered well through the spring. Upon harvest, it was one of the best yielding fields in the area.
Nebraska Extension has published an excellent fact sheet, “Estimating Winter Wheat Grain Yields.” It includes a method for evaluating damaged wheat crowns and for determining plant yield based on plants per foot of row at different row spacings.
Wheat reseeding studies have been conducted by Extension researchers in Colorado and Kansas. Winter wheat that emerges in the late winter generally yields about half as much as fall-emerged wheat. Furthermore, grain test weights are normally two to three points less on late winter plantings.
Flowering and grain fill of early March-planted wheat takes place seven to 14 days later than fall wheat plantings. This increases the potential for exposing wheat heads in these critical growth stages to hotter and unfavorable summer conditions.
Plant stand studies from Kansas and the Nebraska Panhandle Extension researchers complement these reseeding studies in helping determine when to keep a marginal wheat stand in favor of reseeding or interseeding. The gist of these studies is that when one has about a third of a wheat stand, it is better to keep it than to reseed.
Having five wheat crowns per foot of row for a 12-inch planting is about one-third of the normal stand. If portions of a field suitable for interseeding have an average of three or fewer plants per linear foot, replanting is probably justified. Having four plants per foot of row is at the break-even point, so replanting is at the farmer’s discretion.
Make the decision whether or not to replant based on doing footwork in the fields, assessing the plant stand. Make it soon. The decision should be made as soon as possible.