As the wet and cold weather continues to delay fieldwork and the window for spring small grain seeding is closing, you may be considering alternatives. Broadcast seeding methods, whether by air or with a pneumatic fertilizer spreader (floater), are an emergency option you can consider if you plan to stick with spring wheat and other small grains. The chances of success are greatly improved when you consider these planting methods.
- Broadcasted seed will need to be incorporated with some light tillage. Tillage prior to seeding is less critical if fall tillage resulted in a smooth and even field. A tillage operation following the broadcasting of seed is needed to incorporate the seed. Incorporation is essential to create seed to soil contact needed for successful germination and seedling establishment. Harrowing often is enough. Incorporation of the seed with tillage will result in variable seeding depth.
- The seeding rate will need to be increased, as the stand loss percentage due to seed placement that is too deep or too shallow will increase. Research in Ohio and Wisconsin with winter wheat showed that the seeding rate needed to be increased by 15%. Local experiences with spring wheat point to an increase of 10-20%.
- Broadcast seeding is an emergency option. Using a floater has the advantage that you will be able to spread fertilizer in a single pass. Expect uneven and often delayed emergence. Barley will be most sensitive to incorporating the seed too deep, while oats will have the most tolerance to seed being placed deeper than the optimum 1.5 in.
Research has shown that, on average, yields decreased 1% per day when planting is delayed past the optimum planting date. Planting after the last possible date is not recommended because the odds that grain yield and quality (test weight) will be dramatically reduced due to heat stress.
You can partially offset this yield loss by increasing the seeding rate and ensuring that you have more main stems per unit area. The recommendation is to increase the seeding rate by 1% for every day after the optimum-planting window. The last possible date for planting is not chiseled in stone. The chances of a profitable crop just drop because of the anticipated weather and temperatures later during the growing season.
Past the last possible date, you may want to consider an alternative crop, though economic reality might prevent this. If you stay with small grains past that date you will have to hope for a cool and dry summer.
The yield potential of a crop is largely determined by the 6-leaf stage. Cool temperatures during this period are particularly important for the development of a high yield potential. Because of the expectation that average temperatures will be higher as we plant later, development of the crop will speed up, too.
The number of heat units required for a plant to move to the next phase of development will accumulate faster. This forces development along faster and causes the plant to have less time to grow. Plants end up with fewer tillers, smaller heads and fewer and smaller kernels per head, cutting into yields. To improve the odds of high grain yields is to ensure that the tillering and head initiation phases occur during relatively cool temperatures by planting early. Early planting is pivotal in this regard.