Weekly Field Crop Report
By Ned Birkey, MSU Extension Educator Emeritus; Spartan Ag; [email protected]; September 10, 2020
Weather Beth Hall of Purdue University has no expectation that below normal temperatures will persist into the second half of September. However, she has a better outlook for below normal precipitation. Despite the calls for frost and even freeze warnings in the upper Midwest, there is no expectation of that in our area. As a reminder, the MSU updated 30-year average date for a 32oF frost for Monroe County is October 18 and the 28oF first freeze date is November 5. At the MSU Enviroweather station located in Deerfield, rainfall since April 1 has totaled 12.41 inches, which compares to 21.55 last year and a four-year average (not including this year) of 16.72 inches. Growing degree totals since April 1, base 86oF for corn are 2610 GDD this year as compared to 2490 last year and a five-year average (including this year) of 2646 GDD.
Corn Bob Nielsen of Purdue writes this week that drooping ears on corn plants prior to physiological maturity is a signal that grain fill has slowed or halted. Ears on corn normally remain erect until some time after physiological maturity (black layer development) has occurred, after which the ear shank eventually collapses and the ears droop down. The normal declination of ears after maturity is helpful of shedding rainfall prior to harvest and avoiding the rewetting of the kernels. Farmers can estimate corn grain yields now using one of two methods. The yield component method estimates the number of corn kernels per acre and uses an adjustment factor to convert the number of kernels into bushels per acre. Take samples from at least three areas within a field to be more accurate. Count the number of harvestable ears in a 1/1000th of an acre, normally 17 feet and 5 inches for corn in 30-inch rows. Select three ears to count the number of kernels per row and rows per ear to get a number of kernels per ear. Multiply the kernel number times 1000 and divide by 85 (an average ear size factor). This factor assumes about 85,000 to 90,000 kernels per bushel. Estimating the ear size factor will also be helpful in adjusting up the cornhead and combine settings. Make sure the combine has a fire extinguisher aboard and keep a small first aid kit next to the cooler.
Soybeans Farmers can see a number of issues in soybeans now that some plants are dying while others remain green. Diseases such as Phytophthora root rot are common. Take a shovel to dig up, not pull up, plants to examine the roots for color or Soybean cyst nematode (SCN). The Michigan soybean checkoff program will pay for 20 free soil samples submitted to the MSU Diagnostic Clinic. Bean leaf beetles will feed upon the softer soybean pods in late maturing soybeans in green fields. Upon pod maturation, these feeding holes are entry points for moisture and airborne plant pathogens that may cause discolored, moldy or shriveled beans. If pods are turning yellow to yellow-brown, they will become less susceptible to this feeding damage.
Vegetables This week Marissa Schuh writes about the weather, rainfall, growing degree days and general crop comments. She notes widespread fruit rots and asks commercial vegetable farmers to contact her now for a proper diagnosis. The recent rains have meant more Blossom end rot and Phytophthora root rot (PRR) on pumpkins, squash, peppers and other crops. Phytophthora is a disease that has a very wide crop range, including soybeans, for example. Contact her at [email protected] or 517-264-5309. She now has the ability to do field visits on a limited basis.
Farm Safety Next week, September 20-26 is National Farm Safety Week. Now, before the harvest is a good time to check fire extinguishers and first aid kits before they are needed! With school back in session and some foggy days, make sure the Slow Moving Vehicle emblems are new or cleaned off and not faded.