By Joel Ransom, North Dakota State University Extension Agronomist for Cereal Crops
Source: North Dakota State University
Planting of most crops continues to lag behind the five-year average, and early-planted small grain and corn are just now emerging. Establishing a uniform stand is the first requirement of a high yielding crop. I have not received any reports that there have been problems with stand establishment this year, at least so far, but invariably there are fields where poor stand will seriously limit yield. Challenges with emergence may increase with later plantings unless there are timely rains, as soils are drying out in many regions of the state. Assessing stand establishment soon after emergence is important, as it allows for more time if reseeding is needed. Moreover, in the case of small grains, it is much easier to count individuals plants before tillering begins.
Generally, there is less attention given to stand establishment of small grains relative to corn because the seeding rate used is much higher and because plants are able to tiller and fill-in small gaps effectively. Nevertheless, I believe there is value in determining the percent of sown seeds that ultimately establish. Our most recent field guide indicates that one can expect that 10 to 20% of the small grain seeds will not establish. In some of our counts in our research plots this year, we found between 0 and 40% loss, depending on the location and the seeding rate used. However, most of our locations were within that 10-20% loss range previously mentioned. For reasons that I cannot explain, we found the highest stand losses, as a percent of the seed sown, at the highest seeding rates. We have noted this trend in previous years. As mentioned previously, I think there is value in knowing what level of stand loss occurs in your fields especially if you can relate it to soil conditions, equipment used, weather or other factors. Learning from fields with poor establishment is important so that causal issues can be avoided or procedures modified so that stand losses in the future can be minimized.
For fields of small grains with serious stand establishment issues the following are our current recommendations:
1- If the reduced stand is uniform (no big skips or holes), keep stands of 15 plants per square foot.
2- If skips are large (3 to 6 feet) or holes are 4 to 6 feet in diameter and the stand is 18 plants per square foot or less, then replant if moisture is adequate.
3- After June 1, replant with a crop other than wheat or barley since yield loss will be substantial when planting after this date compared to normal planting dates.
Relatively speaking, plant populations play a much more important role in corn yield potential than they do in small grains. Corn emergence is lagging significantly behind previous years though the recent warmer weather has been favorable for emergence and growth. Given the lateness of the season, evaluating corn stands should be given priority if a decision on replanting might be needed. Estimate your plant population by counting the number of emerged plants in a thousandth of an acre (17’ 5” and 23’ 10” row lengths for 30 inch and 22 inch row spacing, respectively) in about 20 places in your field and then multiple the average of those counts by 1,000. Use Table 1 to estimate the likely yield of your current crop and the likely yield if you replant.
These data (Table 1) suggest that even a half stand planted early will be more productive than a full stand planted after the June 1st. Of course, uniformity of the field and uniformity of emergence can also be factors to consider when looking at the potential productivity of your field and the need for replanting.
If you determine that replanting is required, chose a hybrid that is earlier than the “full-season” hybrids recommended for your area of the state, along the lines of the recommendations given in my Crop and Pest Report last week. Also, take into account the final planting date for full insurance coverage for corn in your area. When replanting, the original stand of corn should be destroyed before you replant. Late-planted plants that grow next to an early-planted plant will be at a competitive disadvantage and will not likely produce an ear.
Originally posted by North Dakota State University