600 Maintaining Yields In Hedgerow Almond Production

Abstract

Four tree training methods have been evaluated since 1979 in California for their affect on yield of “Nonpareil” ctv. almond [Prunus dulcis (Mill.) D.A.Webb] in a tightly spaced “Nonpareil”/”Price” ctvs 1:1 hedgerow planting. Four variations of open center training began at the first dormant pruning in a 2.2 × 6.7-m spacing (667 trees/ha): 1) Temporary Hedge—trees trained to three primary scaffolds, standard pruned with alternate trees gradually whisked back to allow space for permanent trees and then removed at 8th year leaving 4.4 × 6.7-m spacing(333 trees/ha); 2) Permanent Hedge—trees trained to three scaffolds, standard pruned at 2.2-m spacing; 3) Two-Scaffold Hedge—Trees trained into “perpendicular V” two scaffold configuration, standard pruned at 2.2-m spacing; 4) Unpruned Hedge—Trained to three scaffolds then left essentially unpruned at 2.2-m spacing. Replicated yield data accumulated over 15 years shows no difference in production between the three permanent 2.2-m hedgerow methods. Yield for the Temporary Hedge, however, declined 30% the year following alternate tree removal. Adequate canopy expansion resulted in some regained nut production, but yields never recovered and remain 20% below the permanent hedge treatments 13 years post-removal. Observations indicate considerable loss of fruitwood has occurred in the lower canopy of all three 2.2-m hedge treatments, especially in the Unpruned but good commercial production has been maintained at 2400 to 3000 kg/ha The size of almond kernels was not affected by training method. Trunk circumference was affected by treatment. Trees in Temporary Hedge plots grew sustantially larger after alternate tree removal than trees in all 2.2-m hedge treatments that were equal in size.