Farming is an occupation that is ruled by the seasons. In the "lazy days" of late summer there may not seem to be a lot of activity in the fields, but one of farming annual rituals is now underway. Several ag groups and businesses are conducting yield surveys. The results of these surveys will be hot topics at fairs, field days and coffee shops. Is the crop as good as it looks from the road or did the recent dry weather and heat have an impact on its potential?

You can easily do your own yield survey. As long as you don't mind walking into 7-8 foot tall mature corn fields in August. I recommend early in the day as soon as the dew has burnt off.

For corn, go into the field collect a random sample of ears and check the population density. The formula for estimating corn yields is easy to remember. Take the average number of kernels per ear times the average number of ears in a thousandth of an acre and then divide by 90. These results are still just an estimate because they don't fully take into consideration variations in kernel weight.

The soybean formula is much harder to memorize. It starts off fairly simple but gets complicated. Start by taking the average number of pods per plant times 2.5 seeds per pod divide by 2900 seeds per pound then divide by 60 pounds per bushel times the average number of plants per acre. Determining the number of plants per acre can be a little tricky. Rowed beans can be done just like corn, measuring off one thousandth of an acre, 17 feet 5 inches for 30 inch rows. However, in drilled beans with 7-inch rows one thousandth of an acre is 74 feet 8 inches, not quite as practical. Using a hula-hoop, just like early season stand counts, might be little more reasonable. Do not put to much faith in these yield estimation techniques. These formulas make a lot of assumptions. The elevators buy based on weight not number of kernels and beans. When test weights are low and seed size is small these formulas tend to over estimate yield.

While you're counting the pods it is a good idea to be on the lookout for insect damage. We saw some soybean aphid populations increase drastically in many areas over the last two weeks. During the growing season we don't get too excited about a little insect damage, but when damage starts happening to pods we get excited pretty quickly. Bean leaf beetles, grasshoppers and stink bugs are some of the main culprits. For both bean leaf beetles and grass hoppers, if more than 5 to 10 percent of the pods are injured an insecticide treatment may be warranted. Beetle damage is generally only to the surface of the pod, but enables disease infection that can interfere with seed development. Grasshoppers may eat all the way through the pod and into the seed. Stink bug damage isn't as obvious; their piercing mouthparts leave little evidence of damage. Stink bugs inject digestive enzymes as well as providing a route for infection to enter the pod.