Wheat Tissue Sampling April 7, 2017

At last, a few moments for a lab note! 

We sampled 24 of our 40 plots for biomass and sent the samples off for tissue sampling at the Clemson labs.  Growth stage was at flag leaf emergence.  The results are in Figure 1 where treatments are shown as N-P2O5-K2O which are simply lb/ac equivalents of N, P2O5 and K2O fertilizer.  

 

Figure 1: Mean Wheat Biomass and Plant Tissue Percent by Treatment

A few observations from Figure 1 are that the biomass, %plant tissue N, P, and K all seem to be dependent on how much nitrogen was added - this is not a new observation (for the %P and %K).  Keep in mind that no P has been added to these plots for two years. Also note that the averages of the plant tissue %K were no different for the 90-0-0 and 90-0-90 treatments, i.e.,  it seems like the potassium added in November made no difference to the plant tissue P.

Bottom line here though is that, based on biomass and almost identical plant tissue samples we are in for a second year where we won't see any difference between the 90-0-0 and the 90-0-90 treatments.  If the harvest bears out what we saw on April 7,  it means that once gain (we saw it in the 2015 wheat, and beans and in the 2016 corn) the $22/acre spent on potassium fertilizer was a complete (I am not exaggerating) waste of money.