Corn Plant Tissue Results May 27
Because we had not yet raised all our funding at the time of the sample, we took plant tissue samples from the first 12 plots (3 reps) to give us an indication of what might be happening. The raw graphic results are shown in Figure 1, the treatments of N-P2O5-K2O are shown on the x-axis. Red lines indicate the lower level of the sufficiency ranges for the element in question e.g., lower level of the sufficiency range for corn in the vegetative stage is 3%. The Check plot on the extreme right of the plot is sample from a plot that has no fertilizer whatsoever. From Figure 1, at least two samples from our 50-0-0 test came back below the sufficiency range for N, one for plant tissue K (140-0-0), while Ca and Mg were at or below the sufficiency levels. The N concentrations are self-explanatory and I'll pass for now on why we had a low/marginal K on the one plot. Ca and Mg appear to be low not just for these plots but also for other fields I have sampled. Not sure if this is due to cooler wetter weather, any insights would be appreciated. Soil test Mg numbers are all in the sufficient range (>60 lb/ac), while 68% of the soil test Ca samples are in the sufficient range (800 lbs or more) - what we'll need to do is check for sensitivity to Ca in this analysis.
What is remarkable from Figure 1 is that while no phosphorus (P) was added, we saw all tissue samples come back well into the sufficiency range. While this is only for this field, I have yet to find a corn plant tissue sample this year (and I have around 50 samples taken) that display any phosphorus deficiency.
Statistically, the only results that were different from one another were the plant tissue N results for the 140-0-85 and the 50-0-0 treatments (Table 1).
Figure two provides plots of fertilizer N (lb/ac) vs plant tissue N (including the check plot), we included fertilizer N vs. %P and %K and fertilizer K vs %K.
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