First Hollow Stem Update And Fall Forage Wheat Yield Report

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. 5, 2016 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 23 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 in Table 1. As of Feb. 5, all the monitored varieties have < 0.1 cm of hollow stem and therefore are far from achieving FHS, which occurs at 1.5 cm (about a half-inch). In most cases, there was no separation between the growing point and the crown area, indicating that the hollow stem did not begin to elongate at this point.

From a FHS perspective, producers grazing wheat in the south central region of Kansas do not have to worry about removing cattle from wheat pastures at this point, regardless of variety selection.

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. Photo by Romulo Lollato, K-State Research and Extension.

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.

Wheat fall forage yield

Forage yield by variety produced during the fall of 2015 is also reported in Table 1. Wheat forage is of very high quality, with 25-30% protein content, and available at a time of the year when other forages are low in quantity and quality.

Wheat fall forage production is largely a function of planting date, seeding rate, and moisture and temperature conditions during the fall. Earlier planting dates at higher seeding rates, coupled with a warm and moist fall, will result in greater forage yield.

The wheat harvested for fall forage yield in this report was planted at 120 lbs/ac for dual-purpose production, but was sown relatively late for a dual-purpose system (Sept. 26). According to OSU research, delaying planting date in two weeks from September 11 can reduce fall forage yields in as much as 1,000 lbs/acre. Still, the long and open fall of 2015 allowed for mean forage yields measured on Jan. 6 ranging from about 1,250 to 1,970 lbs/acre (Table 1).

Table 1. Length of hollow stem measured Feb. 1, 2016 and fall forage yield measured on Jan. 6, 2016 of 23 wheat varieties sown Sept. 26, 2015 at the South Central Experiment Field near Hutchinson. The critical FHS length is 1.5 cm (about a half-inch).

Figure 2. Wheat forage yield sampling on Jan. 6, 2016 near Hutchinson. Photo by Romulo Lollato, K-State Research and Extension.

Source:ksu.edu