The field above averaged 213 bu/acre of corn in 2008. It was fall molbboarded and spring worked twice before being planted to soybeans this spring. As you can see very little residue remains on the soil surface allowing for quicker soil warm-up.A temporary short period of limy green soybeans was noted before nodule formation occurred but growth has been reasonably close to normal.
Other growers who had similar top yields in 2008 but left their corn residues either partially worked in or all on the surface have experienced slower soybean development and a longer period of slow growing limy yellow soybeans.Part of the reason for this is that last years heavy residues have kept the ground cooler and wetter.This has slowed overall growth and curtailed the plants ability to produce root nodules which are the Nitrogen fixers for the crop.Another factor is that soil microbes are trying to break down the extra Carbon in the soil from last years high yielding crop residues.To break this carbon down these soil microbes are tying up a lot of the mineralized N in the soil.
With the tie up of a lot of the mineralized N by these soil micobes the crop is not able to capture as much N from the soil.Also with nodules not yet fully functional soybeans are expressing a more limy green appearance like that shown in the field above. As long as we soon get some heat nodules will kick in gear and soybeans will turn a dark green.Another factor that could be responsible for some of the yellowing being noted in soybean fields is the slower metabolism of the crop particularly where glyphosate has been applied.Glyphosate binds to an enzyme in the plant which will move to the meristematic tissue.Under slow growth the presence of this glyphosate/enzyme complex can cause the plant to slightly yellow.There should be no alarm for this but it can make a grower slightly uncomfortable to see it happen to his crop.
The field above averaged 213 bu/acre of corn in 2008. It was fall molbboarded and spring worked twice before being planted to soybeans this spring. As you can see very little residue remains on the soil surface allowing for quicker soil warm-up.A temporary short period of limy green soybeans was noted before nodule formation occurred but growth has been reasonably close to normal.
Other growers who had similar top yields in 2008 but left their corn residues either partially worked in or all on the surface have experienced slower soybean development and a longer period of slow growing limy yellow soybeans.Part of the reason for this is that last years heavy residues have kept the ground cooler and wetter.This has slowed overall growth and curtailed the plants ability to produce root nodules which are the Nitrogen fixers for the crop.Another factor is that soil microbes are trying to break down the extra Carbon in the soil from last years high yielding crop residues.To break this carbon down these soil microbes are tying up a lot of the mineralized N in the soil.
With the tie up of a lot of the mineralized N by these soil micobes the crop is not able to capture as much N from the soil.Also with nodules not yet fully functional soybeans are expressing a more limy green appearance like that shown in the field above. As long as we soon get some heat nodules will kick in gear and soybeans will turn a dark green.Another factor that could be responsible for some of the yellowing being noted in soybean fields is the slower metabolism of the crop particularly where glyphosate has been applied.Glyphosate binds to an enzyme in the plant which will move to the meristematic tissue.Under slow growth the presence of this glyphosate/enzyme complex can cause the plant to slightly yellow.There should be no alarm for this but it can make a grower slightly uncomfortable to see it happen to his crop.
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