Pedestrian orchards offer potentially significant savings in labor costs for California’s stone fruit growers, but industry officials have never evaluated the orchard systems for feasibility and affordability. A new research project is evaluating the concept of a true pedestrian orchard and the potential for it being adopted by growers.
Kevin Day, University of California Cooperative Extension tree fruit farm advisor for Tulare County, is leading the project to assess pedestrian orchard systems in a side- by-side, uniform setting, to allow growers to see early and late-season peach and nectarine varieties grown on the industry standard rootstock Nemaguard and on the University of California’s newly released size-controlling rootstocks Controller 9 and Controller 5. Trees on Controller 9 are about 90 percent of the vigor of Nemaguard, with Controller 5 trees being about 50 percent the size of Nemaguard.
The trial, to be planted at UC’s Kearney Agricultural Center in Parlier this spring, will compare planting densities ranging from 202 to 622 trees per acre and six rootstock/training system combinations—the hexagon-V (vase), quad-V, and two-leader KAC-V. All trees will be kept at a height of 7 to 9 feet, except for one of the Nemaguard treatments that will be allowed to grow to an industry standard of 12 to 13 feet. Trees in a second Nemaguard treatment, planted at the same spacing as the first, will be kept at the same height as the trees on size-controlling rootstocks in the study. The project is funded by the California Tree Fruit Agreement.
Previous research has shown that reducing tree size from 12 to 9 feet reduced labor costs by about 35 percent, according to Day. Trees on Controller rootstocks are smaller and less vigorous than conventional trees. However, growers and researchers want to learn if the smaller trees will carry and size fruit as well as those on more vigorous rootstocks like Nemaguard. Fruit size has been a problem with dwarfing rootstocks in other crops like cherries. Growers have had to learn new management techniques, such as pruning and training methods, to overcome small fruit.
The research will show if the Nemaguard trees can be kept as short as the trees on dwarfing rootstocks and still reap the benefits of the Nemaguard rootstock—nematode resistance, large fruit, and earlier fruit maturity.
“I still think that we may be able to do it with Nemaguard. It’s always easier to do nothing to a tree for training and pruning than to have to do more to accomplish the same thing.”
Day said that while the goal to reduce or eliminate ladders from orchards is laudable, emphasis must continue to focus on fruit quality and yield. The pedestrian orchards cannot be so expensive that growers cannot afford to plant them.