Wheat Nutrition – Secondary Macronutrients and Micronutrients

March 12, 2008

  Richard Taylor, Extension Agronomist; rtaylor@udel.edu

Sulfur (S)
In past years, quite a few small grain fields located on sandy soils in both Delaware and Maryland have shown large areas of yellowed, stunted plants for both wheat and barley. Usually symptoms are noticed or appear shortly after spring fertilization with nitrogen (N). In many cases, deficiency of either S or Mg has been confirmed with both tissue and soil samples. Examples of fields showing classic deficiency symptoms for S are shown in photos 1 to 4. The symptoms include stunting of plants, general yellowing or chlorosis especially of the new growth (remember that S is immobile in the plant causing symptoms first to occur on new growth but when deficiencies are severe symptoms can involve the whole plant), and poor root development. In the barley shown in Photos 1 through 4, the root systems of the affected plants were limited to the upper 2 to 4 inches and the soil type was loamy sand. Read the rest of this entry »

Small Grain Weed Control

March 12, 2008

Mark VanGessel, Extension Weed Specialist; mjv@udel.edu

If you did treat your fields in the fall for weed control, is time to be scouting the crop. Weed control is important to achieve maximum wheat yields. There are a number of good herbicides for small grains, provided they are used at the proper time. Weeds need to be small (less than 2 inches in height or diameter) and actively growing. This often requires a separate application for herbicides since this often does not coincide with nitrogen applications. Often weeds are not actively growing during the first nitrogen application and then weeds are too large (and wheat interferes with herbicide coverage) at the time of the second application.

Fields that were no-tilled or where chickweed emerged shortly after planting in the fall are fields to check first for spring treatment. If you have wild garlic or Canada thistle, the time of application should be delayed since you need to spray these weeds when they have fully emerged. Yet, coverage is important for these species; so allow adequate emergence, but do not wait too long. If weed pressure from winter annuals is great, it may not be possible to get control of the winter annuals and perennials with one application. In that case, two applications may be required. Read the rest of this entry »