Fall forage production and first hollow stem date in small grain varieties during the 2017-2018 crop year

June 2018


Introduction
Fall forage production potential is one of the major considerations in deciding which variety to plant. Dual-purpose wheat producers may find varietal characteristics, such as grain yield after grazing and disease resistance to be more important selection criteria than an advantage in early forage production potential. Forage-only producers might place more importance on planting an awnless wheat variety or one that germinates readily in hot soil conditions. Ultimately though, fall forage production is a selection criterion that should be considered.
Fall forage production potential is determined by genetics, management and environmental factors. The purpose of this publication is to quantify some of the genetic differences in forage production potential and grazing duration among the most popular small grain varieties grown in Oklahoma. Management factors such as planting date, seeding rate and soil fertility are very influential and frequently more important than variety in determining forage production. Environmental factors, such as rainfall amount and distribution and temperature also play a heavy role in dictating how much fall forage is produced. All of these factors, along with yield potential after grazing and the individual producer’s preferences, will determine which variety is best suited for a particular field.

Site descriptions and methods
The objective of the fall forage variety trials is to give producers an indication of the fall forage production ability of small grain varieties commonly grown throughout Oklahoma. The forage trials were conducted under the umbrella of the Oklahoma State University Small Grains Variety Performance Tests. During the 2017-2018 crop year, the forage trial was conducted at Chickasha, Haskell and Stillwater test sites. Additionally, first hollow stem measurements were collected at Chickasha and Stillwater. Weather data for those locations are provided in Figures 1 through 3.
A randomized complete block design with four replications was used at each site. Plots at each location were established in a conventionally tilled seedbed and received 50 pounds per acre of 18-46-0 in furrow at planting. The seeding rate for each small grain at all three locations was 120 pounds per acre for wheat, triticale and rye; 96 pounds per acre for barley; and 65 pounds per acre for oat. Forage was measured by hand clipping two, 1-meter by 1-row samples approximately ½ inch above the soil surface from the interior rows within each plot. Two separate forage clippings were collected at each location. After the first clipping at Chickasha and Stillwater, plots were mowed to 2.5 inches to simulate grazing. For these two locations, the results for each clipping is presented, and the combined total of the two clippings represents the fall forage yield potential. At the Haskell location, plots were not mowed after the first clipping. For this location, the results for each clipping are presented and represent a forage stockpiling scenario. All samples were placed in a forced-air dryer for approximately seven days and weighed. Fertility, planting date and clipping date information is provided in Table 1.
First hollow stem sampling began at the end of February at the Stillwater and Chickasha locations and continued every three to four days on a by-variety basis until varieties reached first hollow stem. Plant samples were collected for each variety by digging an approximately 8-inch section of row and selecting 10 plants randomly from this sample. The largest tiller on each plant was split longitudinally, and the hollow stem below the developing grain head was measured. Varieties were considered at first hollow stem when the average of the 10 plant samples was 1.5 cm or greater.

 

Figure 1. Average daily temperature (line graph) and rainfall (bar chart) from Sept. 1, 2017 to March 31, 2018 at Stillwater. Weather data courtesy Oklahoma Mesonet.

 

Figure 2. Average daily temperature (line graph) and rainfall (bar chart) from Sept. 1, 2017 to March 31, 2018 at Chickasha. Weather data courtesy Oklahoma Mesonet.

 

Figure 3. Average daily temperature (line graph) and rainfall (bar chart) from Sept. 1, 2017 to Dec. 31, 2017 at Haskell. Weather data courtesy Oklahoma Mesonet.

 

Table 1. Location, planting, clipping and soil information       
STP: soil test P index; STK: soil test K index.
Planting dateSampling datesSampling datespHNSTPSTK
Chickasha0/25/1711/16/1712/18/176.59637277
Haskell9/11/179/3/1712/14/17----
Stillwater9/15/1711/14/1712/13/175.1166128313

Results
The 2017-2018 wheat fall forage production season cannot be described other than disappointing for most producers. Adequate soil moisture was present at the end of August through the first few days of September. Those who planted during this window and were able to protect the crop from fall armyworm achieved good stands and had some available pasture later in the fall. However, for those who waited until mid-September or later to plant, the soil moisture quickly dried up and most wheat was sown into dry conditions. Some producers did receive precipitation in late-September, but other than that, the rain did not return for the rest of the fall. The result was a limited number of days of grazing or no available pasture at all. Dry conditions also remained throughout December, January and into February. A widespread rainfall event finally occurred in late February. Temperatures toward the end of winter remained cool, and the wheat broke winter dormancy almost two weeks later than normal. Although the cooler temperatures persisted throughout the time for cattle removal, the dry conditions did not provide a good opportunity for grazed wheat to recover.
The forage trial at Stillwater was ‘dusted-in’ on Sept. 15. The trial received 3.5 inches of rain from Sept. 25 to Sept. 27 and another 3.5 inches of rain on Oct. 4. Unfortunately, the portion of the field where the triticale, barley, rye and oat plots were located had significant ponding issues, and that portion of the trial had to be abandoned. Fortunately, the winter wheat varieties were at least spared from this issue. Limited growth occurred during the fall and little forage accumulated after the simulated grazing in November. Average total winter wheat fall forage production at Stillwater was 1,480 pounds per acre (Table 2), which was 1,310 pounds per acre less than the 2016 average and 1,200 pounds per acre below the 10-year average at this location. The range in forage production was 1,840 to 1,080 pounds per acre.

CR-2141 Table2

The forage trial at Chickasha was sown into moist soil, and good stands were established. However, overall growth was less throughout the fall and, similar to Stillwater, limited regrowth occurred after the simulated grazing in November. The average total fall forage production at Chickasha was slightly better than Stillwater at 2,060 pounds per acre (Table 3), which was 1,860 pounds per acre below 2016 and 720 pounds per acre below the four-year average at this location. The range in total forage yield was 2,560 to 1,490 pounds per acre. Average total fall forage production for the triticale, rye, barley and oat varietes was 1,940; 2,180; 1,950; and 1,020 pounds per acre, respectively (Table 4).

CR-2141 Table3

CR-2141 Table 4

The Haskell location also received limited rain in the fall. The rains were timely, however, and the forage production was much greater. Average winter wheat forage collected in December was 4,190 pounds per acre (Table 5). The average forage production for the triticale, rye, barley and oat varieties was 3,770; 3,960; 4,110; and 4,900 pounds per acre, respectively (Table 5).
First hollow stem data are reported in ‘day of year’ (day) format for the winter wheat varieties in Table 6 and the triticale, rye, barley and oat varieties in Table 7. To provide reference, keep in mind that March 1 is day 60. The beginning of 2018 was the opposite of that experienced in 2017. Cooler-than-normal temperatures resulted in a much later break from winter dormancy, and overall crop development was slow during this time. The average winter wheat first hollow stem date at Stillwater was day 70 (March 10). This was 19 days later than in 2017 and 10 days later than the 20-year average at this location. At Stillwater, there was a 20-day difference between the earliest and lastest varieties, compared to only a nine-day difference in 2017 and a 15-day difference in 2016. The average winter wheat first hollow stem date for the Chickasha location was 64 (March 4). There was a 25-day difference between the earliest and latest varieties, compared to a 12-day difference at this location last year.

CR-2141 Table 5

 

CR-2141 Table6

 

CR-2141 Table 7

 

Acknowledgments
The authors want to thank the Oklahoma Wheat Commission and the Oklahoma Wheat Research Foundation for providing partial funding for this research.

Seed Sources and Abbreviations
AGSECO = AGSECO Inc.
AgriMAXX = AgriMAXX Wheat
CROPLAN = CROPLAN by WinField United
Dyna-Gro = Dyna-Gro Seed
KWA = Kansas Wheat Alliance
LCS = Limagrain Cereal Seeds
Northern Seed = Northern Seed, LLC / TRICAL
OGI = Oklahoma Genetics Inc.
OSU = Oklahoma State University
PlainsGold = PlainsGold Seeds
AgriPro = AgriPro|Syngenta Seeds
USDA = United States Department of Agriculture ARS
Watley = Watley Seeds
WestBred = Monsanto Co./WestBred Wheat

 

David Marburger
Former Small Grains Extension Specialist

Robert Calhoun
Senior Agriculturalist

Brian Pugh
Northeast Area Extension Agronomist

Branden Watson
Graduate Research Assistant

Christopher Gillespie
Graduate Research Assistant

DASNR Extension Research CASNR
OCES  Contact
OCES
139 Agricultural Hall
Oklahoma State University
Stillwater, OK 74078
OKLAHOMA STATE UNIVERSITY