As we move into August corn growers begin to think about harvest.  Aside from the current poor prices in the market, growers must consider when to harvest and how to handle the crop.  One of the frequent questions is at what moisture level should I begin harvest?  With low prices it’s tempting to leave the crop in the field until dry (15.5%) moisture but that may not be the best choice.  With low prices the only way to reap a profit is to increase yield or at least capture to most yield from the planted acres. There are several factors to consider in determining when to harvest.  These include shrinkage, the cost of drying and field loss.  The real risk here is from field loss since shrinkage is the water weight lost due to the dry down of the grain (either in the field or taken as shrink at the elevator) and the cost of drying is somewhat stable whether taken  as a discount at the elevator or  dried on the farm.   Field loss can be described as ear loss either from stalk lodging or ear loss primarily due to a severe storm or prolonged period of wet weather which can result in ear rot, losses in kernel weight or aflatoxin.  Given, greater field losses can be tolerated with lower prices to offset the price of drying but in any case, growers should not allow the grain to dry down below 15.5% unless storing on the farm for 3-4 months.  Anything below this and growers are leaving weight and profit in the field.  For assistance in calculating costs and risks review the article by Dr. Ron Heiniger.