COMPARISON OF NO HEDGING, MECHANICAL SKIRTING AND MECHANICAL HEDGING TO MANAGE A HEDGEROW HOWARD ORCHARD AT MATURITY

Orchards that are planted in a hedgerow configuration eventually require some type of canopy management to allow safe machinery access down the drive row. The orchard age when this occurs varies depending on tree spacing, variety, orchard vigor, rootstock, etc. The Howard on Paradox orchard described here is the same orchard where a pruned versus unpruned trial took place from 2003 to 2010 (see Lampinen et.al, 2010). By 2010 the yields for all pruned and unpruned treatments were similar, as was midday canopy light interception, so the current trial was overlaid over the previous trial with individual rows serving as the treatment unit. OBJECTIVES The objective of the current study was to test different methods of managing a mature hedgerow Howard planting. The goal was to provide safe access for machinery down the drive row with minimal impacts on yield and or quality. An unhedged control was left to provide a reference to how much yield impact was occurring as a result of the mechanical treatments. PROCEDURES Site description- The orchard is located at Nickels Soil Laboratory in Colusa County and is a Howard walnut on Paradox seedling rootstock planted at a spacing of 14’ x 21’. The orchard was planted in 2002. The orchard averaged about 3.1 to 3.4 tons per acre of production for the 20082010 seasons. Hedging and skirting treatments- The hedging and skirting were performed on 4/18/11. Treatments were imposed on row middles from 33 to 47 trees in length. There were five replications of each of three treatments. No hedging or pruning was done on the unhedged treatment. The skirting treatment consisted of an approximately 45 degree angle cut from near the tree trunk to about 8 feet in height as shown in Fig. 1. Width of the bottom of the hedging cut was about 5 feet with an approximately 7 degree angle in towards the tree at the top of the cut as shown in Fig. 1. The trees were already leafing out by this date and this delayed hedging (rather than dormant hedging) may have impacted results.