Do you remember the field conditions from two years ago in your soybean fields? Shaun Casteel says you would if you had detailed notes on early emergence to refer back to. Casteel is the Purdue University Extension soybean specialist.
Take notes of seed rates and field conditions, he says. Early season notes from planting to emergence can help to assess conditions favoring disease infection, such as dampening off or SDS, and herbicide injury.
They can also help document performance of field preparations, planting equipment, varieties and seed treatments.
Here’s how to develop a systematic approach so taking notes.
Step one: Track a few fields closely once soybeans start to crack the ground. Earlier plantings typically take longer to emerge, maybe 14 to 21 days, since the soil is taking longer to warm up compared to late plantings, when emergence may be in five to 10 days.
Step two: Simply mark off a few rows with flags. Two 1/10,000th of an acre equals:
• 42 inches of one 30-inch row
• 42 inches of two 15-inch rows
• 42 inches of four 7.5-inch rows
Step three: Count the number of emerged plants in that area daily at roughly the same time each day. You could count them twice a day if you want a fine resolution.
Step four: To calculate your plant population, divide the total number of plants by 2 and multiply it by 10,000. For example, 26 plants ÷ 2 × 10,000 = 130,000 plants per acre.
Step five: Compare these emergence notes on dates, rates, and total stand to variables in your scenarios and heat units accumulated from planting to emergence, and from cracking to complete emergence.
This intense emergence evaluation will help give you an indication of the performance of your planting and stand establishment – field preparations, equipment, variety, and seed treatment under the growing conditions you just experienced. It will also help you diagnose potential problems this year and guide decisions for next year. Contact Casteel by email at: [email protected] or visit: soybeanstation.org.