Lessons From the 2009 Wheat Crop Year

By David Boehm

After five years of writinga wheat-season article, I can say that no years were exactly the same. But at least the last five years were collectively average!

WEATHER As always, wheat production can be narrowed down to two main factors – water and temperature. 2009 did produce differences across the four state region, but mostly, it was cool and wet, perfect for small grains. For most, a delayed planting season put wheat development under the gun, however we didn’t experience above average temperatures for the entire wheat growing season. This allowed wheat the time to mature naturally. Considering the late planting, this temperature factor was very good. Moisture varied from month-to-month, but much of the region had ample rainfall. The exception here was an area of east central ND where growers said they received less than 3” all growing season. North-central ND was also dry late season. The stored soil moisture and cool temps still provided good yields. Western ND had far above average moisture for much of the season.

YIELD VS PROTEIN The cool and wet season had profound impacts on grain yield, protein and disease development. It’s no question that most of us thought wheat yields would be reduced because of the generally late planting. I’m sure everyone remembers the cost of nitrogen last winter and spring, so it might have been easy to adjust fertility levels to correspondingly lower yield expectations. But the cool conditions and adequate water allowed for much higher than expected production. Yields in western regions could be considered 2x normal for many growers. Hindsight as it is, there is no surprise to see protein levels reduced. There was little stress on the wheat crop as we did not experience normal heat or drought stress in late summer. Test weights were incredible and conversely, most, if not all, varieties had 1-2% less than “normal” protein. A normal plant response is to “finish” by storing protein in the berry. In the absence of stress, the plant continues to store carbohydrates all season long. Thus we get increased test weight and higher yields, with lower protein %. Remember that we talk of protein as a % of the grain kernel, not protein produced per acre.As I talked with growers post-harvest, most confirm that all varieties had lower-than average protein, particularly when yields were high. In cases with more average farm yields, the protein levels were also closer to the average. Also of note, varieties responded as they should have. If you group varieties by their genetic protein potential, the categories of lower protein, average protein, and higher protein held true. Higher yielding varieties still had comparatively lower protein, depending on fertility.

DISEASE The other impact of the growing environment is disease development. Fortunately there isn’t much to talk about here. Tan spot is an early and cool season disease and it continued to show up. As normal, tan spot was most common in western regions with no-till or reduced tillage and less broadleaf rotations, but tan spot was also prevalent in the east. Early fungicide applications with the herbicide did a good job of control. One thing of note this season is that the cool summer temps were within the preferred range of tan spot, so we did see this pathogen continue on after early fungicides would have run their course. Leaf rust was nearly non-existent however there were moderate levels in some locations in western ND and eastern MT. Lighter levels of rust came in late season and were fairly benign. Frankly, it wasn’t warm enough for rust and little innoculum was present in the central or southern plains. Scab was also not a big concern for most. While I did see low levels of scab throughout the region, even western ND, it appeared on only the most susceptible varieties and caused low-level damage. Bacterial blight continues to be an issue for some, yet it’s unclear how much of a problem it really is. Areas in west-central MN and north-central SD were hit pretty hard. We still see more damage when heavy rains occur at early growth stages. Increased attention is being paid to bacteria by extension and university pathologists and plant breeders. In late October, a group of researchers organized to coordinate information and possible research.

PLANT GROWTH Since wheat is a cool-season crop that, we noticed above average plant growth and tillering this year, particularly in the central and western regions. In fact, the heaviest occurrence of plant lodging was in south-west ND where taller varieties with less straw strength are common. I received more calls than ever about the tall plants sticking out above the field, questioning genetic purity. Cool temps enhance internode or stem elongation, so any slight differences in the dwarfing genes found in semi-dwarf varieties were exhibited this season. Remember wheat isn’t 100% genetically pure, usually 92-95%. Certain varieties, and older seed, will show more tall plants and this year was perfect for that extra growth. In hot or dry years, you won’t see this effect. Therefore, seeing these off-types can be a sign of better yield potential (or old seed).

WHEAT STEM SAWFLY One final topic of 2009 was the increased occurrence of wheat stem sawfly (WSS). WSS continues to be a major pest problem in western ND and throughout MT. While solid-stemmed varieties offer the best management, they generally yield less. NDSU has released a new solid-stemmed variety, “Mott” that looks very promising. Another solid-stemmed variety will be released from AgriPro in 2011. For growers with this issue, continue to learn about production practices from entomology and wheat specialists from NDSU, and from Montana State University where WSS has been a long-term problem. Topics might include broadleaf crop rotations, variety blends, and refuge borders.

NEXT YEAR So let’s look at next year, bearing in mind what we just went through. Although there probably are long-term weather forecasts, unless I know when and how much moisture, and when and what the temps will be, I’ll continue to manage wheat for the unknown.

Protein and yield are inversely proportional. Extra N is needed for higher yielding varieties and in years with more yield potential. We still need to follow the most recent yield and N guidelines to keep good protein levels. A crop consultant in central ND had a field hit 93 bu/a while maintaining 15% protein after a late N application. Given these growing conditions, supplemental N could be considered as your yield goal changes.

Always grow multiple varieties. Yield potential, protein potential, and disease tolerances should be utilized in different varieties. Don’t forget about scab, even if we haven’t seen epidemic levels since 2005, it will come back. Always spread out maturity ratings. A long-season maturity is favored in years like 2009, but not a hot or dry year. I know growers that planted large percentages of their farm to high yielding varieties (or one variety) that don’t have good protein potential. I heard more than a few tell me they weren’t going back with those varieties. A good strategy is to always have an adequate varietal mix.

Soil test to see how temp and moisture affected your carryover fertility. Some agronomists suggested to me that the wheat may not have used the nitrogen available in 2009 since it was never stressed, adding that soil N levels are still high after harvest. Others have suggested low levels of N depending on crop use and moisture. Ultimately, know where you start after an unusual year. Keep in mind that less fall tillage affects organic matter mineralization.

Get a germination test on your grain if you intend to keep it for seed. A lot of pre-harvest glyphosate was used to push harvest along. Especially if it was used at higher grain moisture, it might have an adverse effect on seed germination. I would advocate that getting germination and seed count on grain used for seed is always the best money you can spend. Call your state seed certification agency for information. (ND State Seed Dept, 701-321-5400; MN Crop Imp Assn., 800-510-6242; SD Crop Imp Assn., 605-688-4606)

Finally, it’s too easy to overreact to the growing season we just finished. I’ve seen where we switch to scab tolerant varieties, higher protein varieties, better straw strength, or different maturities, all because of what worked, or didn’t, last season. Just like an investment plan, have a balanced approach with multiple parts and don’t react too much – unless you know the future! Best wishes next season.

Boehm is regional manager for AgriPro Wheat and a board member of the MN Crop Improvement Assn., with a master’s degree in plant breeding from NDSU. He can be reached at david.boehm@agripro.com.