Reason to be concerned about your wheat crop

(The following information was published in the Jan. 23-Feb. 6 Ohio State University C.O.R.N Newsletter. The information was compiled by state specialists Jim Beuerlein, Pierce Paul, Ron Hammond, Robert Mullen, Edwin Lentz .)
COLUMBUS – A cool, wet September delayed the maturity of most bean fields last fall and harvest got off to a late, slow start. We had November weather in October, with two days to harvest and then seven days to watch it rain, two harvest days and then more rain.
Some northern producers were able to plant wheat timely because of their short season beans and because some of the rain missed their farm. Southern Ohio was wetter than northern Ohio through most of October.
Throughout Ohio, the inability to harvest beans interfered with wheat planting, which was either later than desirable or not at all, especially in southern Ohio.
To our memory, 2006 was the latest, coldest, and wettest harvest season of the last 40 years.
Wheat suffering. As we start a new year, much of the wheat crop does not look good, and many fields have either poor or uneven stands.
We question whether these late start wheat fields will survive till spring. Many of the fields with good stands have not tillered well, and will need to finish that process next spring, which means heading may be later than normal, the grain filling period shortened and yields reduced.
However, we have seen some limited growth due to the warm weather the last half of December and early January.
Standing water in low spots has killed the plants in those areas and the location of tile lines is evident in many fields, reinforcing the point that soil drainage is a crucial part of a wheat production system.
If you are an optimist, then March and April will be warmer and drier than normal, wheat will tiller well, head on time and produce a great yield.
Many producers did not get enough acres planted, or planted later than they intended to plant or under less-than-ideal conditions.
Moving forward. There are lots of questions about what can be done to improve the outlook for the crop and compensate for the lack of planted acres. Following are some of those questions and our answers:

Can I plant winter wheat really early next spring and get a good crop?

Winter wheat will not joint and produce a stalk and head, grain or straw, unless it is exposed to about 15 days of sub freezing temperatures after germination. Winter wheat planted next spring will not produce a crop.

Given that the winter has been unseasonably warm, has our wheat received the minimum number of days of cold temperatures it needs to produce a crop?

Based on the temperatures we have had over the past few days and predicted temperatures for the latter part of January, our wheat will be vernalized at the end of that period.

Does the wheat require a minimum of 15 consecutive days of cold temperatures or a minimum total of 15 days of cold temperatures?

No! The requirement is for a certain amount of “cold” expressed as a combination of both temperature and time of exposure to that temperature.
For example, the effect of 20 hours of 25 degree temperature may be equivalent to the effect of 30 hours of 31 degree temperature. The exact requirement for each variety is unknown, but we have never had a problem to date with the crop not getting vernalized.

What is the grain and straw yield potential for planting spring wheat early next spring?

The grain and straw yield potential of spring wheat varieties planted early in the spring is around 50 percent to 60 percent that of our soft winter wheat varieties. Also, our market is for soft wheat and there are no soft spring wheat varieties available.
Ohio’s flour mills purchase some hard wheat to make special purpose flour. Most of that grain is produced through prearranged contracts and for the production of specific varieties.

How early and what amount of nitrogen should I apply next spring to increase tillering?

Applying N at greenup may stimulate growth sooner than later applications but most likely will not increase tillering or yields.
Tillering is a function of carbohydrate availability in the plant, which depends on photosynthesis, sunlight interception and plant size. Each plant can produce over 50 tillers but can support only a few of them.
We are most concerned about how large the tillers are at green-up and not so much about their number.
Do not apply N sooner than initial greenup. Potential for N loss greatly increases with applications prior to greenup. Consider urea or ammonium sulfate instead of 28 percent for early greenup application (less chance for N loss).
Nitrogen rate should be adjusted to reflect any changes in expected yield. If N was applied in the fall, a producer may want to delay spring nitrogen until a decision can be made on whether to keep or discard a poor wheat field.
Ohio State University research has shown that yields generally are not reduced if spring N is applied sometime prior to early stem elongation.
Split applications may be more N efficient in some years but generally are not as economical as a single spring application, even for poor stands.

I no-tilled my wheat in late October and am wondering if I should have disked before I planted.

Most fields had smaller than normal wheat plants at the onset of winter which makes them more susceptible to heaving next spring. If your crop was planted without tillage, the potential for heaving next spring is reduced regardless of plant size.

My wheat is thinner than normal by about 20 percent. How will that affect my yield?

Seeding rate studies indicate that wheat yield is affected only slightly by seeding rate because of its vast tillering potential.
Currently, the thin stands are generally associated with the later plantings or poor planting conditions. Tillering typically compensates for some reduced stand when planting is accomplished in a timely manner.
We are most concerned about the late planting and slow start of the 2007 crop. Plant population will likely have more effect on yield in 2007 than normal, but that effect will not be nearly as great as the loss due to late planting.

My wheat got planted late and was only 2 inches tall at Christmas. Should I start planning now to switch crops?

We may have an early spring and end up with a great crop in spite of the poor start. By early April we will be better able to evaluate a field’s potential and have two to six weeks to switch crops if needed.

Should I fill in the drowned spots and thin areas with a spring wheat variety?

No! A hard spring wheat variety will mature about two to three weeks later than our winter varieties and interfere with harvest of those areas. Elevators often will not accept mixtures of hard and soft wheat because the mixing destroys the utility of each grain type.
Also, hard spring wheat varieties are not adapted to our environment and are susceptible to many of the diseases that our winter varieties are resistant to.

Is there anything positive to be said about this wheat crop?

The beneficial effect of our late planting is that very little if any disease got started in the fall, and we probably escaped much of the normal fall insect damage. Therefore, two yield reducing stresses that normally occur in the fall have been eliminated and that condition may add some bushels.
However, the late planting will not reduce potential damage due to armyworm, wheat sawfly, or other insects that attack the crop in the spring, nor will the crop be protected from spring diseases such as powdery mildew, head scab and Stagonospora.