MY SOYBEANS DISPLAY DIFFERENT SHADES OF GREEN - WHAT CAUSES THIS ?
The above colour difference is due to a recent herbicide application.Under certain environmental conditions there will be a lightening up in the chlorophyl concentration and a so called limy green or yellowing observed.It generally lasts for only a temporary period.
ON the other hand mottled shades of green across a field is generally an indication of different N rate availabilities caused by differences in root nodulation and Soil N mineralization.
Temperature differences across a field due to differences in residue coverage,soil texture differences,internal drainage differences, top soil depths and Organic matter differences are what makes differences in soil N mineralization and nodulation take place which in turn causes a crop to take on different shades of green colour.
The less N being made available is generally a big factor in why the crop appears lighter in colour.With time these colour differences will disappear and the crop will seemingly even out.
Then again differences in green colour across a field can be nothing more than the differences in the chlorophytic green expression that different soybean varieties can express at an early growth stage.The above photo is a good illustration of this as it is actually a soybean plot that shows a big contrast in green between one variety and another.