By Randy Weisz and Ron Heiniger
Small grain tillers produced in the fall are most likely to have large heads with kernels of high-test weight, which are the two components of a high-yielding crop. Fall tillers also tend to have stronger root systems, which may make them more stress resistant. Because fall tillers are an important component of high-yielding small grains, timely planting is important.
In addition to good soil fertility and adequate soil moisture, temperature also affects tiller production in small grains. The warmer the weather, the more tillers are likely to be produced. Cold temperatures hold back growth, so it is important to plant small grains early enough for tillers to form before winter sets in.
Figure 7-1. Opening planting dates for North Carolina. Increase seeding rates by 15 percent each week after the end of the opening dates for your area.
WHEAT
It takes approximately 60 to 70 heads per square foot to produce high-yielding field of wheat. When this many tillers are produced in the fall, the crop will be off to a good start. Starting planting dates (necessary to produce these tillers in different areas of North Carolina) are shown in Figure 7-1.
Based on average weather, if wheat is planted on the first day of the starting period, enough tillers develop by February 1 to produce as many as 90 heads per square foot. Such a crop needs little or no early spring nitrogen and has a high yield potential.
If wheat is planted at the end of the starting period (about 2 weeks later), the expected growth of the crop will be reduced. By February 1, tillers to produce only 45 potential heads per square foot will have developed. This crop may add the needed extra tillers in February and early March, but it will likely require nitrogen early in February to produce those tillers.
If wheat is planted later than the starting period, increase the seeding rate.
What about planting earlier? A rule of thumb is to plant wheat within 1 week of the first frost. Wheat can be planted earlier than the dates given on the planting date map, if:
Optimal planting dates for barley, oats, and rye are given in Table 7-1 below:
Table 7-1. Optimal planting dates for barley, oats, and rye |
|||
Crop |
Mountains |
Piedmont |
Coastal Plain |
Barley, Oats |
9/20 to 10/10 |
10/1 to 10/25 |
10/15 to 10/30 |
Rye |
9/25 to 11/1 |
10/15 to 11/10 |
10/15 to 11/20 |
Triticale varieties that have been developed for North Carolina, such as Arcia, can be planted on the same dates as wheat. Most other varieties, such Trical 498, are at risk to spring freeze and should be planted 2 weeks later than wheat.
Heavy residue left on the soil surface can reduce soil temperatures. This results in slower germination and tiller growth. Since fall growth can be reduced in no-till, planting small grains early becomes even more important. Establishing a healthy, uniform stand at the start of the optimum planting date window may be a key to achieving high yields in no-till.
Hessian fly has become a serious pest of wheat in North Carolina. Because Hessian fly adults are killed by freezing temperatures, a traditional method for preventing Hessian fly infestation is to delay planting until after the first freeze (often called the fly-free date). But this has not worked well in North Carolina because an early freeze is not a dependable event. A killing freeze often does not occur until December in many areas of North Carolina, which is past the date most growers need to have wheat planted if they want to have enough fall growth to produce high yields. Delayed planting will only prevent Hessian fly infestations if a freeze has occurred.
Timely planting is a critical component of high-yielding wheat. Planting during the opening planting dates can reduce the need to apply nitrogen early in the spring. Timely planting promotes fall tiller growth, which maximizes head size and increases the potential for high-test weight. Wheat can be planted earlier if a frost is expected, if experience has shown there is acceptable risk to Hessian fly, barley yellow dwarf, and winterkill, or if an insecticide and fungicide seed treatment combination is used to control powdery mildew and barley yellow dwarf. Wheat planted after the opening planting dates should be seeded at a higher rate.
Some materials in this chapter were adapted from Intensive Soft Red Winter Wheat: A Management Guide, Blacksburg: Virginia Polytechnic Institute Cooperative Extension Service.
This file is a chapter from Small Grains Production Guide, 2004-05. Recommendations for the use of agricultural chemicals are included in this publication as a convenience to the reader. The use of brand names and any mention or listing of commercial products or services in this publication does not imply endorsement by the NC Cooperative Extension Service nor discrimination against similar products or services not mentioned. Individuals who use agricultural chemicals are responsible for ensuring that the intended use complies with current regulations and conforms to the product label. Be sure to obtain current information about usage regulations and examine a current product label before applying any chemical. For assistance, contact your county Cooperative Extension Center.
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Last Revised Sept. 2004