Question:

Noticed in 23 pnut prodn info book the recommendation for gypsoil gypsum is 1200# for va pnuts? I use product out of ADM Southport. I have been using 2000#/ac rate. Your thoughts?

Jordan:

We base the recommendation on percent calcium in the material. Check behind me but we have that product at 85% calcium sulfate. You don’t need any more gypsum than the rates listed in Table 3-9 for the percent calcium sulfate that is listed. Sometimes a half and suggested rate work similarly. But sometimes there is a clear difference between these rates in favor of those listed in the table.

We can apply too much gypsum if pH is low. So if pH is 5.9 or higher, extra gypsum does not cause a problem. But no positive benefit. At a pH of less than 5.9, in the 5.5 range, higher rates of gypsum can reduce yields. My recommendation is that if you find yourself with low pH, put out half the rate in the table. If at optimum pH, apply the rate in the table.