Question:

What KI do you use as a cutoff for not putting any potash out on peanuts? The soybean folks are telling me they are recommending 50 for soybean now.

Jordan:

Anything below 70 needs some potash. At 50, NCDA&CS recommends 30 pounds per acre. [Table 3-8 in 2022 Peanut Information lists a series of K indices and rates of potash recommended for this nutrient.]

Follow up:

Okay yes, I understand but most applicators can't spread 30 pounds. You have to round up to 100 pounds product which would be 60 units of K.

Jordan:

Agree, equipment can't go that low. Based on yield calibration curves from years ago, the need is there if KI is below 70. If soil test indicates a need, I would apply the lowest possible rate the equipment will deliver. I realize this is extra as KI approaches 70 and that fertilizer is expensive, but I would not short the plant. I am not aware of any data sets that are available that show a relationship of yield versus KI that could be used for a net return calculation.