Seasonal Issues Power for Soybeans and Corn


Inadequate pod sizing on soybeans and ear sizing on corn

Inadequate number of seeds per pod on soybeans and kernels per ear on corn

Inadequate sizing of seeds on soybeans and kernels on corn


As the soybean plants become older, the new growth slows down.  This causes inadequate auxin synthesis in the soybean plant. The level of ethylene and ABA increase in the soybean plant.  This is what causes late season stress. Therefore, the soybean plant must be kept alive and pods forming on the upper third of the plant.

If there is adequate rain and warm temperature during the latter part of the soybean season, the leaves tend to hold their sugars and do not transport them to the stem and developing seed and pods.  Therefore, the amount of gibberellic acid in the leaves must be down regulated and the amount of ABA in the leaves be increased. This will cause immediate movement of sugars.

On a corn plant, the supply of auxin decreases as the corn plant tassels.  The pollination from the corn tassl is dependant upon adequate auxin for pollen viability. If the plant has serious stress, beginning one week before tasseling and continuing two weeks after tasseling, the auxin level is further decreased and the level of ABA is increased. This causes smaller ear sixe, abortion of kernels at the end of the cob, and smaller kernels.

The late season help for both soybeans and corn is significantly important in order to gain the maximum number of seed and the maximum size of the seed or kernels.


The application of Bio-Forge at the rate of 1.0 pint per acre on soybeans at the R4.5 to R5.0 stage of development, will maintain plant health, vigor and increase the amount of sugar transport from the leaves to the developing pods and seeds.

The application of Bio-Forge at the rate 1.0 pint per acre on corn at the V12 stage (approximately 1 week before tassel shows) will increase the plant vigor, even during drought situations.  It does so by regulating the hormone balance in the corn plant. The plant will maintain more auxin for pollen viability and will reduce the level of ABA in the developing ear. Ear size will be larger and the number of viable kernels on the ear will increase. Also, the kernel size will be greater.

The above treatments on both soybeans and corn are designed to maintain plant health in the latter stages of growth in order to maximize yields of both crops.

J/JHS articles/PEP Late Season Plant Power for Soybeans and Corn 052107 bc