Yellow Soybeans Need Sun

Chad Lee, Extension Professor and Agronomist, University of Kentucky

Numerous fields of soybeans appear yellow or bright green right now. The symptoms mimic nitrogen deficiency, but the plants are really starving for air to the roots and sun on the leaves. Everyone is thinking about applying some nitrogen to help make the plants greener. But what these plants really need is for sunshine to help partially dry the soils.

Poor or No Soybean Nodules in Many Fields

Chad Lee, Extension Agronomist, University of Kentucky

A field with soybeans with nodules
and soybeans without nodules. 

Several soybeans have turned yellow in the past few weeks and further examination revealed little to no nodules. The problem has occurred with seed inoculated in the bag and seed inoculated at the farm. It has even occurred in cases where a 2x rate was applied at the farm. Several brands of inoculant have been indicated. It has occurred in fields all across the state. The problem has occurred in full season soybeans and in double-crop soybeans.

Good Corn Yields Despite Nitrogen Losses

Chad Lee, Extension Agronomist, University of Kentucky

Excellent seed fill,
even though N deficiency is evident.

Corn in most fields across the state displayed nitrogen (N) deficiency before black layer was reached. Those losses were expected this season as we experience more rain. Normally, we expect yield losses to occur when the corn crop runs low on N before the seeds are done developing on the cob. However, walking some of these fields reveals that corn yields should be very good despite the apparent lack of N.