We Are Still Very Early, but if Crop Stands Are a Concern…

May 10, 2023

By Osler Ortez and Laura Lindsey et.al

We are still early, but if you planted in April or the first few days of May, soil conditions have been wet and cold in many parts of the state. Early plantings, cold air/soil temperatures, and precipitation cause slow progress in corn and soybean. In Figure 1, corn and soybean plants slowly emerge from the ground under wet soil conditions. The pictures were taken during the first week of May—almost three weeks after planting.

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One of the downsides of planting early is the risk of seeds sitting too long in the field. Seed damage (biotic or abiotic) can lead to reduced stands in planted fields. Factors to consider are imbibitional chilling, frost damage, seed treatment duration/viability, insect/disease damage, soil crusting, and standing water. These factors (or combinations) can negatively affect seedling vigor, plant growth, crop establishment, ultimately reducing crop stands. If reduced stands are a concern, a potential solution is to replant fields. However, we are still early to make accurate assessments of crop stands.

Our 101 recommendation now is to wait… Crop stands should be assessed after ‘stable’ and ‘better’ conditions are achieved (e.g., warmer temperatures, adequate soil moisture conditions):

For corn, past work has shown that 50% emergence can be expected following accumulation of 150 soil GDDs (base of 50°F) from planting, about 5-7 days under normal conditions (much longer under cold/wet as areas of Ohio have been).
For soybean, assess the stands no earlier than the VC growth stage. Visual stand assessment at the VE growth stage often underestimates the number of plants that will emerge.

Often, hasty decisions are not the best. When replanting decisions on early planted acres are made, one should be careful about getting more plants than necessary in the field. In the following picture (Figure 2), the first set of soybeans was planted early and took a long time to emerge from the ground. So, a replanting decision was made (replanted at an angle). Once the weather conditions turned better, the first planting and replanting came up, in which case the replant was unnecessary. We suggest caution when replanting decisions are made.

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Figure 2. Soybean field with plants from first planting and plants from replanting (at angle) in Ohio.

According to the USDA-NASS report for the week ending 05/07/23, 11% of Ohio’s corn and 16% of Ohio’s soybean acres were planted. In 2022, the same period showed 5% corn and 4% soybean planted acres in the state. Only about 2% of corn and soybean were reported emerged in this week’s report. Ohio’s planting (and emergence) progress has a long way to go. Following the OSU Agronomy Guide recommendations, this article lists key reminders/considerations for planting season this year.

Follow more planting and other Agronomic Crop Updates here (C.O.R.N. Newsletter) or visit the Ohio State Agronomy YouTube channel.

Crop Observation and Recommendation Network

C.O.R.N. Newsletter is a summary of crop observations, related information, and appropriate recommendations for Ohio crop producers and industry. C.O.R.N. Newsletter is produced by the Ohio State University Extension Agronomy Team, state specialists at The Ohio State University and the Ohio Agricultural Research and Development Center (OARDC). C.O.R.N. Newsletter questions are directed to Extension and OARDC state specialists and associates at Ohio State.

Source : osu.edu