Crops & Conservation

by Blake Vander Vorst
bvandervorst@ducks.org

Notes and Observations from the 2006 Winter Wheat Crop

The 2006 growing season accentuated what is often an advantage of including winter wheat in the crop rotation: the one to two week earlier maturity of winter wheat lessened the impact of the extreme heat and drought Mother Nature ‘shared’ with many of us in the Northern Plains this summer. 

Indeed, an extremely important factor in winter wheat’s performance is the crop’s ability to avoid some of the moisture and temperature stress because of its earlier maturity.

More observations from the 2006 winter wheat growing season follow, with acknowledgements to Joel Ransom, Marcia McMullen and Kent McKay of NDSU, Jochum Wiersma at the U of M, David Boehm of AgriPro Wheat, and Roger Knapp, DU field agronomist, for their contributing observations in preparation for this article.

CDC Buteo and Radiant hardiness stands out

The 2005 season provided for a fair number of prevent plant acres for winter wheat to be seeded at an earlier date in northeast N.D. and northwest Minn.  This ground had a full soil profile of water and as mentioned, the winter wheat was early enough to avoid most of the heat and drought in 2006.

Winter survival was average to good across the region with the above average winter temperatures. There was some stand loss due to dry conditions at seeding in the fall of 2005 preventing adequate establishment. Minimal field losses occurred from ice damage associated with the freezing rain after Thanksgiving in southeast N.D. and eastern S.D.

The hardiness of two winter wheat varieties caught my attention this past year at our research site with SDSU at Bristol, S.D. CDC Buteo and Radiant are two of the most recent releases from Canada. I seeded the remaining excess seed of these two varieties in a bulk area. The increased survival last spring was apparent for the two varieties, especially when compared to Jagalene, which I also planted in the bulk area. Jagalene is a variety bred for the central and southern plains that has less winter hardiness. 

Data from the Hettinger Research Extension Center winter wheat variety trial indicated a similar trend. Dry conditions at seeding and through the winter resulted in significant stand losses that resulted in highly variable data. Despite the variability, CDC Buteo and Radiant caught my attention because of their winter survival ratings of 87% and 90%, respectively. The next closest survival ratings were in the low 60% range.

Damage from the November ice storm was most prevalent when winter wheat was seeded into very short stubble or soybean stubble where the stubble height was below 3 or 4 inches.  If there was adequate standing stubble that was visible through the ice layer, there seemed to be adequate oxygen flow to prevent suffocation.  It was also fortunate that the soil temperatures were still warm prior to the storm. The ice layer actually melted or turned to a granulated porous structure within a few days as a result of the soils’ warmth.

Fungicide response, wheat streak mosaic

The dry summer weather in 2006 provided for minimal disease pressure as compared to the severe scab, rust and leaf spot diseases experienced in 2005.  It again lends credence to the mantra not to base variety selection on one year of data, because of the differences in the growing season environment from one year to the next.

Dr. McMullen indicated that most of the variety trials had minimal visual symptoms of leaf and head disease. Yield response to fungicide application was negligible at a number of the sites, including Kent McKay’s trial at Minot.

However, some variety trial sites had significant yield increases due to fungicide application, such as Lisbon. There was a 14.7 bushel per acre yield increase averaged over the varieties to a Folicur fungicide application at the early flower stage of growth, increasing the yield from 80.4 to 96.1 bushels per acre. 

A trial DU conducted at Steele, N.D. with 12 varieties, with only two replications, showed a 7.1 bushel yield increase from a four-leaf stage Stratego fungicide application when the prior crop was flax. This was a bit surprising, as I did not expect to see any response considering the dry conditions and flax being the prior crop.  However, the cooperating grower, Tim DeKrey, reminded me that there was some early precipitation in April and early May, and there was considerable dew in the mornings prior to application.

Overall, fungicide response was variable depending on location and yield level. Yield increases from fungicide application can still happen when disease pressure is low and winter wheat yield potential is high, as they were at the NDSU trials at Lisbon and Prosper.

Wheat streak mosaic was observed in northern N.D. and in one field in northwest Minn.  Dr. McMullen and Kent McKay said the infections were the result of two separate management issues.  Winter wheat volunteers from the 2005 winter wheat crop were not controlled until May, 2006. This allowed the spread of the virus to a neighboring spring wheat field that had emerged prior to the desiccation of the volunteer winter wheat. 

The other scenario found prevent-plant fields from 2005 being planted to winter wheat in early to mid-August. Winter wheat fields seeded prior to September are at very high risk of being infected with the wheat streak mosaic virus by the wheat curl mite. They were planted early because of farm program seeding date requirements for cover crops.

To manage wheat streak mosaic, control volunteer small grains and grassy weeds two weeks prior to seeding winter wheat to eliminate the “green bridge.” Wheat streak mosaic is spread by the wheat curl mite, and volunteer small grain and grassy weeds are the hosts for the mite. Eliminating the grassy hosts breaks the life cycle of the mite and stops the spread of the disease. Neighboring corn fields can also be a host for the mite.  Seeding later during the optimal seeding period can assist in reducing exposure to wheat streak mosaic as well. NDSU has a wheat streak management bulletin online at www.ag.ndsu.edu/pubs/plantsci/smgrains/pp646w.htm.

HRW vs HRS yields

Winter wheat yield reports this year have ranged from 30 to 90 bushels per acre outside of the extreme drought area of south central N.D. and parts of S.D. Spring wheat yield reports I have received have ranged from 10 to 65 bushels per acre in the same areas.  The spring wheat yields were heavily influenced by planting date and crop rotation. A few growers who seeded spring wheat in late March to early April had yields that rivaled their winter wheat, but these growers were far and few between.

As a whole, yields were probably average, but when compared to other early season crops, they seemed very good. It was common to hear reports of winter wheat yielding 10 to 20 bushels per acre more than its spring relatives.  Yield differences were less in the eastern growing areas and greater as you moved into the drier areas. On average, protein and test weights were very good in 2006.

Promising price outlook

The wheat prices encouraged more winter wheat acreage to be planted this fall.  Winter wheat prices have actually exceeded spring wheat at times this summer.  The Kansas City board of trade July 2007 HRWW contract has topped $5.00 in May, July and October. The July 2008 contract has exceeded $4.90 on several occasions. Some growers have used this opportunity to price some of their 2007 and 2008 production.

With new varieties along with increased knowledge and changes in tillage and crop management systems, new opportunities for winter wheat are developing in the Northern Plains. Finding that winter wheat can help spread workload and risk, many winter wheat growers had a positive experience in 2006 and are excited about the prospects for 2007.

Vander Vorst is regional agronomist with Ducks Unlimited, Inc., Bismarck, N.D. Find more information about DU’s agronomy program, including winter wheat performance data, online at www .ducks.org/conservation/initiative45.aspx - click on the link ‘Agronomy News’