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Soil amendments of complete fertilizer, manure and limestone added to backfill soil at transplanting did not influence pecan tree appearance or growth. Removal of ⅓ or ½ of the top at transplanting was compared with no top removal. Removal of ½ the top improved tree vigor the first year but differences in vigor and growth had dissipated by the second year. With 60 cm diameter holes, vigor and growth increased as depth increased from 30 to 90 cm. Trees planted in a 20 cm diameter post hole had poorer vigor and growth the first two years than trees planted in 60 cm diameter × 90 cm depth hole. Differences in vigor and growth due to hole size also dissipated with time and were not significant at the end of the third year. Pecan trees apparently are resilient and can overcome a poor transplanting job.
NAA was applied to pecan nuts at concentrations of 0, 20, 50, 100, 200, and 500 μg·g-1 on May 19, June 16, and July 20. The 500 μg·g-1 concentration induced nut drop at all dates but was phytotoxic to leaves when applied on May 19. Concentrations of 50-100 μg·g reduced preharvest drop of nuts.
Nitrogen at 112 and 224 kg·ha-1 and K at 0, 56, 112, 168, and 224 kg·ha-1 were applied to young `Desirable' pecan [Carya illinoensis (Wangenh.) C. Koch] trees to evaluate their influence on leaf scorch. Scorch severity in the orchard decreased with time even though large imbalances of N and K existed. Scorch was increased only slightly by the high N and the zero K treatments. Little scorch was observed in trees receiving K applications. Increasing K rates >56 kg·ha-1 did not reduce scorch. Correlation was not significant or very weak for leaf N, leaf K, or the leaf N: K ratio with leaf scorch in the Ray City, Ga. study, depending on the year of observation. Another study at Tifton, Ga., revealed no correlation between scorch and leaf K or the leaf N: K ratio. A very weak correlation occurred for scorch and leaf N in 1 of 2 years.
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 0.75% seemed adequate and practical for the low end of the sufficiency range.
Abstract
Drip irrigation on 1 and 2 sides of pecan [Carya illinoensis (Wang.) Koch.] trees was programmed to irrigate when soil water suction 61 cm from the emitter was greater than 0.1 bar at either 15, 30, or 45 cm depth. Results were compared with no irrigation. The data indicate little advantage of 2 lines of emitters over one line when the same number of emitters/tree are used. The data often favored 1 line over 2 lines. Total yield of pecans was increased substantially by drip irrigation on one side (‘Desirable’ and ‘Elliott’) or both sides of the tree (‘Elliott’), but increases from ‘Farley’ were not significant. In 1968, an extremely dry year, ⅓–½ of the shucks did not dehisce completely on nonirrigated trees while 1 to 7% of the shucks did not dehisce on irrigated trees. Irrigation increased nut size. Percentage kernel was increased by irrigation in 1968 but not in other years. In 1968, percentage fancy kernels was almost doubled by irrigation for ‘Desirable’ but was reduced for ‘Elliott’.
Abstract
Best marketable yields of tomato (Lycopersicon esculentum Mill.) were obtained when the soil pH (Tifton loamy sand) was between 6.5−6.9. Yields were reduced when soil pH was below 6.0. Liming to the desired pH increased the percentage of decaying fruit but decreased the percentage of other cull fruit. Liming increased leaf N, P, Ca, and Mg and decreased leaf Mn, Fe, and B concentrations.
Abstract
Defoliation of pecan trees [Carya illinoensis (Wang) K. Koch] prior to October 1 prevented nutlet formation the next year in 2 out of 3 years. September defoliation was most damaging to yield, October defoliation was less damaging, and defoliation on November 1 did not reduce yield. Early defoliation delayed bud break the next year and August defoliation reduced nut size. Percentage kernel was reduced when defoliation date moved from August 1 to September 15.
Abstract
Fall defoliation was followed by a depletion of carbohydrate (CHO) reserves and reduction or prevention of yield if defoliation occurred prior to November 1. Refoliation of August-defoliated trees restored the depleted reserves in current season’s wood tissues by December 1 but either completely prevented or greatly reduced yield the next year. September defoliation caused the greatest depletion of reserves and prevented pistillate or staminate flower production the next year. Defoliation on November 1 had no significant effect on CHO reserves.
Abstract
Twenty-year-old ‘Elliott’, ‘Desirable’, and ‘Farley’ trees were pruned over, an 8-year period using: 1) pruning on only low and broken limbs, 2) removal of competing wood from alternating temporary trees, 3) top and side hedging, and 4) selective limb pruning. Wood removal from temporary trees was low, except for the last two years of the study, and little difference in yield and quality from the control was obtained. Top and side hedging reduced overall yield of ‘Desirable’ and ‘Farley’ and it changed the alternate bearing phase of ‘Elliott’ so that yields were increased and decreased in alternating years. Selective limb pruning increased yield of ‘Desirable’ in one year but, overall, gave no significant yield changes from the control. Selective limb pruning increased ‘Elliott’ yield in some years and reduced it in others to give an overall reduction in yield. Selective limb pruning did not reduce yield of ‘Farley’ significantly. Selective limb pruning usually increased nut size, and pruning effects on quality were erratic. Both hedging and selective limb pruning usually increased terminal growth. Most parameters measured showed significant cultivar × year × irrigation × pruning interactions.