Long-term performance of pecan trees when potassium application is based on prescribed threshold concentrations in leaf tissue
1994
Worley, R.E.
Potassium was applied to old 'Stuart' pecan [Carya illinoensis (Wagenh.) C. Koch] trees only when leaf concentrations dropped below thresholds of 0.25,0.50,0.75, or 1.00% K or annually, regardless of leaf K. Depletion of K was extremely slow, with soil K concentrations remaining at 68 to 168 kg.ha-1 (medium) or higher in the 0 to 15 and 15 to 30 cm depths after 20 years without K application. No trees were below the 0.25% leaf K threshold over the 20-year period. Yield, tree growth, nut quality, and tree appearance were similar for all K treatments. A leaf K threshold of O.75% seemed adequate and practical for the low end of the sufficiency range.
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