by Dr. Calvin Trostle, Extension Agronomy, TAMU Dept. of Soil & Crop Sciences, Lubbock, 806-746-6101, ctrostle@ag.tamu.edu; Dr. Jake Mowrer, Extension Soil Fertility, TAMU Dept. of Soil & Crop Sciences, College Station, 979-845.5366, jake.mowrer@tamu.edu

Soil & Crop Sciences extension has developed a new publication for Texas wheat. Nitrogen topdress timing involves recognizing the key jointing growth stage in wheat, and understanding when conditions may merit earlier application of topdress N.  Much of the discussion in the new document is presented in the context of twelve common grower questions about N for wheat grain, a subtitle of the publication.

The new publication is posted at http://varietytesting.tamu.edu/wheat as well as our wheat pages at the Lubbock and Amarillo Centers.

A key element in our discussions with Texas wheat growers is an improved understanding of jointing in wheat, and why it is important.  What you visually see in the field is ‘jointing,’ that is, you notice a few stems coupled with erect growth.  If you rub the lower stem between your thumb and forefinger you may feel a small ‘bee-bee,’ or node, within the stem.  This means the growing point for that individual stem is differentiating, i.e., the growing point has switched over from producing another leaf to now determining potential head size (spikelet number, potential seeds per spikelet, Fig. 1).  This is an important component of yield potential.  Because this process for an individual head only lasts about 7 to 10 days, when you see the first few joints then most of the rest of the field has probably initiated growing point differentiation.

Figure 1. Sliced wheat stem reveals young growing point differentiation with hollow stem to the right. Growing point differentiation—spikelet number and seeds per spikelet—is likely complete.

Calvin Trostle
Professor and Extension Specialist
Lubbock, TX
803.746.6101
ctrostle@ag.tamu.edu