By Harold Watters, Ohio State University Extension agronomist
Increased precipitation and extended cold periods into May have resulted in extended/late corn planting for at least parts of Ohio in many recent years. A reduced number of field days in April can be documented with the trend from 1995 to 2020 for five less working days. The prediction for 2021 looks like it will extend this pattern. The La Nina pattern appears to have kicked in, with more moisture and an Arctic outbreak giving us a snowy February.
Aaron Wilson, Byrd Polar Research Center and OSU Extension Climatologist, expects the active La Nina pattern to continue into spring planting season. Precipitation will transition to more rain as we head into March and April. The current Ohio spring outlook is for above average precipitation through at least May-June. His current temperature outlook calls for a warmer than average spring — a typical impact of a La Nina pattern.
A wet spring will often result in an increased number of fields with poorly established corn stands in affected regions. In post planting diagnosis we find a variety of maladies. Uneven seed depth in the furrow or open seed slots are seen where seedlings germinate but do not emerge, or malformed plants that result in lower plant populations and uneven stands. Where soil is too wet, the disk opener smears the sidewall and emerging seedlings are unable to expand the root outside the seed furrow resulting in “Tomahawk” roots. Plants will show various nutrient deficiencies including phosphorous (purple color) or potassium (chlorotic yellow leaf margins) through early vegetative stages. Ultimately the impacts of planting too wet are season long and significantly reduce yields.
Bob Nielsen, Corn Specialist at Purdue University provides some “Factors for successful corn stand establishment.”
- Be Patient! This is easier said than done. But the past few years have shown planting in windows of opportunity where soil conditions match our equipment capabilities have better emergence/stand establishment and avoid replanting.
- Do not fixate on the calendar. Planting in late May/early June still can produce a 200-bushel corn crop.
- Pay attention to the short-term weather forecast. The short term 6-10 or 8-14 day forecast are useful to identify potential precipitation and maybe more importantly temperature conditions. You may not stop planting but an upcoming wetter/colder event could reduce urgency.
- Have the planter repaired, tuned up and adjusted. Be ready for the windows of opportunity where the soil conditions and weather forecast are favorable.
- Operate the planter smartly. Match the depth to soil moisture conditions and be aware of sidewall compaction and forced closure of seed slots. Take a few moments to check position of the seed and slot condition with a shovel after a planter pass.
- Avoid unnecessary spring tillage passes. Tillage that beats soils into a fine powder are more likely to have surface crusting with heavy rainfall events that have become more frequent. If soils are suitable look toward reduced tillage options such as conservation tillage, strip till or no-till.
- Minimize the risk of soil compaction. With soils that never quite dry out tillage results in layers of soil compaction that the plant never grows out of in the current season and possibly affect crops for many seasons to come.
- Consider using 2 by 2 row starter. Starter response is unpredictable and many years we do not see a yield response but in years with a response 10 to 15-bushel increases occur.
If you are interested in more on this topic, search YouTube using “Gambling with planting decisions.”