By Mark Badertscher
Cool, wet soils have delayed the start of planting season this spring in Hardin County. Usually farmers would prefer to begin planting corn in late April to early May. However, the calendar doesn’t always determine the best time to put the crop in the ground. Other factors that come into play are temperature and moisture levels in the soil.
Although it may seem warm outside, the soil temperature must be warm enough for corn to germinate. Corn needs a soil temperature of at least 50 degrees to germinate. This temperature should be measured at a depth of 1 ½ to 3 inches in the soil. Although the soil may be dry enough to plant, if the soil temperature is not warm enough, the seed will not germinate.
Another factor in seed germination is moisture. There needs to be enough moisture in the soil to cause the seed to swell and support germination, but if too much moisture is present, the seed and any existing shoot can rot. According to OSU Plant Pathologist Anne Dorrance, seeds that are exposed to cool, wet soils become subject to pathogens, which can infect seeds and seedling growth.
One of the most common pathogens for corn and soybeans is Pythium. There are 25 different species of Pythium (Dorrance, CORN 2014-10), which can cause damage to seeds and growing roots.
Farmers should plant into well drained soils and use seed treatments to help prevent plant diseases caused by Pythium. Although weather conditions may be favorable to planting, long periods of soil temperatures below 50 degrees along with excessive moisture can cause root and seedling damage, increasing the potential need for replanting.
Another factor that can affect the growth and development of corn and soybeans is soil compaction. If soils are too wet when planting occurs, compaction results which restricts air and water movement through the soil.
Tillage should be kept to a minimum, but enough to allow good soil to seed contact to allow exchange of nutrients. Many farmers will plant crops using conservation tillage or no-tillage operations which limit soil compaction and reduce soil erosion.
Although the soil temperature and moisture are important factors to consider when planting corn and later soybeans, there does come a time when crop yields are affected by planting date. Usually this date is between mid-May or even later for corn, depending on weather conditions. After May 20, farmers may consider changing seed varieties for corn to an earlier maturing hybrid to reduce possible yield losses (Thomison and Culman, CORN 2014-10).
Farmers are beginning tillage and planting operations across Hardin County this week. Although there were a few fields tilled and even less planted before this time, the weather is starting to cooperate and soils are drying more each day. Activity will increase with each passing day depending on the rainfall received, drainage, winds, and temperature. Once the corn is planted, farmers will shift to planting soybeans. Soybeans can be planted later and have more flexibility for growing season adjustments.
During this planting season it is important to be aware of slow moving tractors, trucks, and equipment on the roads during all hours of the day. In addition, fertilizer and sprayer equipment will also be out doing their job. This equipment is wide and travels slowly compared to a car on the road. Keep looking for equipment, flashing lights, and slow moving vehicle (SMV) signs.
This is especially true when coming over a hill or around a curve. Give the farmers and commercial fertilizer/pesticide applicators a chance to do their jobs, so they can get their work done in a safe and efficient manner.
For more information about OSU Extension, Hardin County, visit the Hardin County OSU Extension web site at www.hardin.osu.edu, the Hardin County OSU Extension Facebook page or contact Mark Badertscher, at 419-674-2297.
