Planting Winter Wheat in Severe Drought: What are the Options?
As of Sept. 1, 2022, the entire area of Perkins and Hayes counties is experiencing an “exceptional drought,” the most severe category of drought listed by the U.S. Drought monitor (Figure 1).
Drought conditions have persisted for most of this year’s growing season in Perkins and portions of neighboring counties. According to the High Plains Regional Climate Center, areas of Perkins County have received only five to eight inches of precipitation since Jan. 1, roughly 10 inches below normal.
This situation has undoubtedly left producers wondering what their best options are regarding whether to seed wheat in the coming weeks or look for an alternative.
If the field has crop residue to prevent wind and water soil erosion, the best decision may be not to seed wheat this fall unless we get about three inches of precipitation on soil that is dry (less if the soil has some soil water) before the recommended seeding date of Sept. 15. This seeding date can be delayed to two weeks later (around Sept. 29); however, adjustments should be made to fertilizer applications and planting protocols (see below). The three inches of precipitation will provide enough soil water for the wheat until dormancy this fall.
If none or little precipitation occurs before the first week of October, consider planting proso millet or another low water use crop next spring. This could also include spring wheat depending on fall and winter precipitation.
If the field does not have crop residue to protect the soil from wind and water soil erosion as a result of fallow with tillage, or the crop this summer was hayed or cut for silage, one needs to try seeding a crop to protect the soil. Winter wheat is usually one of the best crops to protect the soil from wind and water erosion. Seeding the winter wheat as soon as one can place the seed at the proper depth and in firm soil, if possible, is usually the best practice.
Do not remove the corn, grain sorghum or other crop residue to be able to seed. The crop residue is easy to cut with no-till drills, but most no-till drills will need additional weight to get the seed to the proper seeding depth in the dry soil. Even with additional weight, it may still not enable the drill to place the seed at the proper depth. The crop residue will protect the soil from erosion and will make any rainfall more effective.
Remember, most winter injury and loss of stands is a result of loose seedbed and seeding depth. Observations over the years resulted in whenever the seed placement was shallow, the stands were not as good and had more injury or loss. For example, with large drills the outer units did not have as much weight per seed unit and the seed was not seeded as deep, and those areas had less stands and suffered more stand loss.
For producers still considering planting wheat this fall, there are two viable options (see NebGuide G2211, "Planting Winter Wheat in Dry Soil"):
Plant and Hope for Rain
Currently, the forecast suggests the current pattern of warm and dry conditions will persist through mid-September. Only seed if you can place the seed at the proper depth, which is one to 1.5 inches in medium to fine textured soils, and two inches for coarse textured soils. In dry conditions, if possible, it is probably best to place the seed at 1.5 in the medium and fine texture soils and make sure that in coarse soils, the seed is at least two inches deep. Seeds should never be covered with more than three inches of soil.
Wait for Rain and Then Plant
The recommended seeding date for wheat in Perkins County is Sept. 15; however, if the choice is made to delay planting, adjustments to the seeding rate, row spacing and fertilizer application should be considered.
Because late seeding of wheat generally results in reduced tiller and root development, seeding rates should be increased. A general recommendation for rainfed wheat is to increase the seeding rate by 10-15 lbs./acre for every week after the suggested seeding date for your area. Keep in mind that the maximum seeding rate for rainfed wheat is 120 lbs./acre (1,800,000 seeds/acre). See Figure 2 for a summary of the yield results of a study conducted by Kansas State University comparing the effects of planting date and seeding rate on wheat yield.
When seeding after the recommended date, the use of narrower row spacings of five to eight inches is preferred over wider spacings of 10-15 inches. If this is not feasible, consider seeding twice by using half of the seeding rate each time with the second pass at a slight angle to the first. (Note: this will only work with disc drills as hoe drills would bury most of the seed laid down on the first pass.)
A study conducted by the University of Nebraska-Lincoln at three locations in Nebraska showed that when seeding wheat late, phosphorous fertilizer placed with the seed helps to improve yield (Figure 3). A general recommendation is to apply 20 lbs. of phosphorous even when none is called for by soil tests. If soil tests do indicate a need for phosphorous over 20 lbs., increase the application rate by 20%.
It is important to note that nitrogen applications with the seed should not exceed 10 lbs./acre in dry conditions. If equipment is not available to place fertilizer in the seed furrow, 11-52-0 or 18-46-0 can be mixed with the winter wheat seed. A good mix is important and fertilizer dealers can usually do this for you. It is often preferable to use 11-52-0 with its lower nitrogen content.
With this method, check to see if you are satisfied with the mix by test drilling on top of the ground so you can observe how well the winter wheat seed and fertilizer are mixed. Be aware that with this method, the fertilizer may cause more wear to the drill. Also, fertilizers can absorb water, so take precautions against this.
Finally, keep in mind that many drills need more weight per seeding unit to penetrate the soil under dry conditions. Keeping seed boxes and fertilizer boxes or tanks close to full if attached to the drill may help in getting the seed to the proper depth. We have even converted 7.5-inch drills to 10 inches to get the seed placed at the proper depth. This does go against the recommendation for narrower rows under late seeding, but the number one goal in seeding is getting the seed to the proper depth.