The 2007 growing season could raise its ugly head and even affect our 2008 soybean crop. Many of the soybean production fields were harvested when the seed was very dry.
This resulted in more than the usual amount of mechanical damage to the seed.
Many seed lots have germination rates lower than normal. In addition, Jim Beuerlein, Ohio State University Extension specialist said that many lots also have reduced vigor and quality.
Seed with reduced vigor is more susceptible to seedling damping off caused by pythium and phytophthora, warned Ann Dorrance, Ohio State University Extension plant pathologist. Fungicide seed treatments will protect this type of seed, especially if it is planted into a field where you have a history of stand establishment problems.
Seed lots are evaluated using two tests. The germination rate that is printed on the seed tag is the result of the warm germination test. It gives the percentage of seeds that are alive and will germinate under ideal field conditions. The second test is called the cold germination test and evaluates the seeds vigor under extremely stressful conditions.
You can get the germination rates from the cold test from your seed dealer.
The exposure to cold wet conditions allows only the most vigorous seeds to survive and be disease free. A cold test result of 70 percent or more indicates the seed is highly vigorous and will provide good emergence under severe field conditions.
Beuerlein said that seed will fall into one of three categories:
•High warm test (90-plus percent) and high seed vigor (70-plus percent).
•High warm test percent but only a medium vigor test (60-69 percent).
•Medium warm test (85-89 percent) germination and a medium vigor test.
The specialists both agreed that all seed should be treated with fungicides for protection from root rot diseases.
You need to be sure you know which of the seed quality categories your lots fall into. This way you can plant the highest quality seed first when conditions will likely be less than ideal. Use the poorest quality seed where you have excellent drainage and when the soil is warm. The views and opinions expressed in this column are those of the author and not necessarily those of Farm World. Readers with questions or comments for Steve Bartels may write to him in care of this publication. |