By Mike Staton, Michigan State Crop and Soil Scientist

Soybean growers often wait to begin harvesting until every leaf has dropped and the moisture level of the soybeans has dropped to, or below, 13%. While these first fields may be harvested at the optimum conditions and moisture level at maximize value per bushel, the plants in the remaining fields will probably become too dry, increasing harvest losses and lost income due to the lost moisture weight. 

The main reason producers delay soybean harvest is to avoid paying moisture discounts or drying charges. The table below clearly shows the net value per bushel of soybeans when delivered at various moisture levels. Even when moisture shrink factors and discounts are applied, it is more profitable to harvest soybeans at 15% moisture than to harvest them at 10% moisture.

These calculations don’t factor in any of the other risks associated with delaying soybean harvest, such as increasing the potential for harvest losses, soil compaction, combine ruts or delayed wheat planting. Shatter losses due to brittle pods increase as moisture levels drop below 11%. They also increase whenever soybeans dry to 13% and then undergo repeated wetting and drying cycles.

A shrink factor of 1.6% per wet bushel increased by 0.8% for each 0.5% moisture above 13.1% was used to calculate dry weight. Actual moisture loss was used to calculate dry weights when moisture was below 13%. Market price is $9 per bushel. Moisture discount/drying charge of $0.05 for each 1% above 13% was used.

Ideal weather and soil conditions don’t last forever. This is another strong argument for taking off some of your soybean fields at 15% moisture as long as the weather and soil conditions are conducive. Every acre harvested under good weather and soil conditions is one less acre that may have to be harvested under poor conditions.

Wheat growers should be especially motivated to harvest soybeans early as wheat yields have been shown to decrease by 1.1 bushels per acre for each day planting is delayed after Oct. 1. The higher wheat yields realized from early planting will more than compensate for the small level of lost income realized by harvesting soybeans at 15% moisture.

Consider harvesting some of your soybean fields at 15% moisture as a way to reduce risk and improve farm income.