Yield potential is maintained with high populations since there are more plants per acre. Soybean populations that are too high also undergo a natural thinning process due to the intense competition between plants, which reduces the stand to a more acceptable level. In other words, plants are eliminated after emergence. In summer, soybean populations can vary perhaps as much as 50 percent from recommended levels without affecting yields, as long as missing plant spaces are not too large and weeds are controlled. Taller varieties that are lodging prone are likely to have reduced yields if populations are too high.
Shorter varieties are more likely to have reduced yields if populations are too low.
In general, fewer problems occur when stands are established at or near recommended levels. It is usually expressed in terms of plants per acre or plants per linear foot of row. The population guidelines in Table 1 are based on responses of different public soybean varieties. Most varieties grown in Indiana will produce maximum yields at these populations but there are exceptions. For determinate varieties, you may need to increase plant populations to realize full yield potential.