First Hollow Stem Update: Feb. 22, 2017

Feb 23, 2017

By Romulo Lollato

Wheat and Forages Specialist

Cattle should be removed from wheat pastures when the crop reaches first hollow stem (FHS). Grazing past this stage can severely affect wheat yields (for a full explanation, please refer to eUpdate article “Optimal time to remove cattle from wheat pastures: First hollow stem” in the Feb. 22, 2017 issue).

First hollow stem update

In order to screen for FHS during this important time in the growing season, the K-State Extension Wheat and Forages crew measures FHS on a weekly basis in 20 different commonly grown wheat varieties in Kansas. The varieties are in a September-sown replicated trial at the South Central Experiment Field near Hutchinson, in cooperation with Gary Cramer, Agronomist-in-Charge of the Field.

Ten stems are split open per variety per replication (Figure 1), for a total of 40 stems monitored per variety. The average length of hollow stem is reported for each varieties in Table 1. As of Feb.17, none of the varieties had yet reached first hollow stem but all varieties had started to elongate the stem.

Figure 1. Ten main wheat stems were split open per replication per variety to estimate first hollow stem for this report, for a total of 40 stems split per variety.

Table 1. Length of hollow stem measured Feb. 17, 2017 of 20 wheat varieties sown mid-September 2016 at the South Central Experiment Field near Hutchinson. The critical FHS length is 1.5 cm (about a half-inch or the diameter of a dime).

While none of the varieties had yet reached first hollow stem as of February 17, this stage is generally achieved within a few days from when the stem starts to elongate, provided sufficient moisture and warm temperatures. Thus, producers should keep a closely monitor first hollow stem in their wheat pastures at this time. In fact, some commercial fields in the region were already at first hollow stem and reaching jointing by February 20 (Figure 2). Our team is performing first hollow stem measurements on February 22 again, and will report these measurements on the February 24 issue of the Agronomy eUpdate.

Figure 2. Commercial wheat field on Feb. 20, 2017 in Rice County planted Sept. 27-30, 2016 showing first hollow stem.

The intention of this report is to provide producers a weekly update on the progress of first hollow stem development in different wheat varieties. Producers should use this information as a guide, but it is extremely important to monitor FHS from an ungrazed portion of each individual wheat pasture to take the decision of removing cattle from wheat pastures.

Source: ksu.edu