Many of the farmers attending the annual agronomy field day on the Montsma Farms in Fond du Lac County on Aug. 27 were concerned that the recent combination of heat and lack of rainfall would prevent their crop from finishing its reproductive stages properly, thereby hurting yields and quality.
Less than 12 hours later, a series of thunderstorms moved through the area from the northwest, providing an inch or more of rain in many cases.
Those storms covered all or parts of the counties in east central Wisconsin from Lake Winnebago to Lake Michigan and northward to areas west of Green Bay.
At the field day here, sponsored by the AgriPartners cooperative and the Fond du Lac County Extension Service office, agronomist and soybean specialist Shawn Conley of the state Extension Service addressed several of the concerns of the soybean growers in the crowd had at the time.
Conley had learned that some growers were thinking about harvesting their crop as forage either because parts of fields were drying prematurely due to lack of moisture or because of concerns that the beans would not be physiologically mature before a killing freeze strikes. He offered several related cautions.
One is that the labeled restrictions for all insecticides and most herbicides, except for glyphosate and very few others, make it illegal to take the soybeans for forage if those products were applied to the crop, Conley pointed out.
This also applies to using any soybeans intended for use as straw, he added.
Noting that the soybeans being grown in the various plots on the Montsma Farms had generally reached the R6 growth stage after being planted in mid-May, Conley stated that this would be the ideal time - both for tonnage and feed quality - to harvest them as a forage feed.
Anyone deciding to take soybeans for forage should remove the foliage from the field before it has dried enough to cause the beans to shatter and be lost, he advised.
Each of the reproductive stages of soybeans generally runs from 10-15 days but the period can be extended or shortened, depending on the availability of moisture, Conley observed.
For example, he said seed fill can occur as quickly as nine days or as many as 30 days, depending on rainfall at the time.
Soybeans are considered to have reached physiological maturity at their R7 stage, Conley noted.
This means there is at least one brown pod per plant - a point at which the crop's yield is safe, he explained.
Although the recent stretches of hot weather have created stress in many soybean fields, this wasn't necessarily all bad, Conley stated.
He noted that the heat pushes the plants toward maturity - a benefit for the significant number of fields which were planted relatively late this year.
During his inspection of the plots here, Conley found a few plants exhibiting several of the most common diseases affecting the crop.
In most cases, it is too late to treat with fungicides, he pointed out.
This is definitely true with white mold, for which the infection period occurs when the spores enter the flowers, Conley indicated.
Despite the concerns about white mold, he said yields are not significantly affected until the infection strikes at least 20 percent of the plants.
Conley announced that a Wisconsin team, headed by now retired agronomist Craig Grau, has succeeded in breeding soybeans for resistance to white mold.
This trait will be licensed to the commercial sector by the Wisconsin Alumni Research Foundation.
There are sporadic outbreaks of phytophthora root rot, which is most easily identified by the brown stems on plants from the ground up, Conley said.
Using the appropriate seed treatment should stem most of the concern with that disease, he suggested.
Sudden Death Syndrome
Sudden Death Syndrome (SDS), a mid to late season threat to soybeans, was first detected in Wisconsin during 2006, Conley noted.
He found a few affected plants here, demonstrating that the white inside of the stem is a reliable sign of the disease while a brown inside would indicate brown stem rot instead.
The weather conditions were perfect for SDS to break out this year, Conley stated.
SDS has been linked to the presence of the soybean cyst nematode in other states but no such link has been proven in Wisconsin, most likely because of the greater prevalence of crop rotations here, he remarked.
Soybean cyst nematode populations have been verified in a great majority of Wisconsin's counties where soybeans are grown regularly, Conley pointed out.
To learn whether they're in particular fields, he urged growers to take advantage of the free testing program - four soil samples per year - offered by the Wisconsin Soybean Marketing Board.
Even without a test, lower yields of soybeans in portions of fields if there is no other evident reason suggests the presence of the soybean cyst nematode, Conley advised.
With an expanded testing procedure to also check for different nematodes which are a pest for corn, 20 percent of the samples tested in 2012 had moderate to high infestations of that nematode, he reported.
The proper control for the corn root nematodes is to treat corn seeds with Avicta or Poncho VOTIVO insecticide, Conley stated.
During 2012, the response to the effectiveness of those treatments in Extension Service plots varied according to the corn hybrid, he indicated.
Winter Wheat Updates
Conley announced that, starting this autumn, a winter wheat plot will be established on a portion of the Montsma Farms here.
Overseen by the Extension Service and the University of Wisconsin-Madison College of Agriculture and Life Sciences, the new plot will replace the one previously located near Lancaster.
The reason for the change is the much higher number of acres of winter wheat grown in Fond du Lac and nearby counties than in the southwestern part of the state, Conley indicated.
He said the new plot will consist of a soybean and winter wheat rotation that will also allow for additional soil nutrient research by soil scientists.
With the planting dates for the next winter wheat crop coming up within the next two months across Wisconsin, Conley urged growers to check the seven-point formula for establishing a successful stand that's available on the coolbean.info website.