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Abstract
Nitrogen and K were applied to 26-year-old ‘Western’ pecan [Carya illinoensis (Wangenh.) C. Koch] trees at 0, 56, 112, or 224 kg ha−1, and 0, 93, or 186 kg ha−1, respectively, for 6 consecutive years (1978–1983). There was a positive relationship between N rate and leaf N concentration and shoot growth. The number of new shoots per 1-year-old shoot was increased by N application. Yield was greater using 56, 112, or 224 kg N ha−1 than no N. Nitrogen rate was negatively related to leaf K concentration and curvilinearly related to leaf Mn concentration, but did not affect leaf Ca or Mg. Leaf P and Zn concentrations were reduced during some years by N application. Potassium application increased leaf K concentration in 1980, 1982, and 1983, but did not affect leaf K concentration in other years. Surface applied K moved to the 30–45 cm depth by 1980 and to the 45–60 cm depth by 1982. Potassium rate was positively related to leaf Mn concentration, but not leaf N, P, Ca, Mg, or Fe concentration. Annual yield was increased by K rate only in 1979, but cumulative yield was positively related to K rate.