An Orchard Blueprint for High Density Apple Plantings
Posted: April 18, 2012
In two videos, we discuss the orchard blueprint concept for increasing orchard efficiency. Here are the orchard blueprint rules for success:
Size controlling rootstocks and tree density between 518 (6 by 14 feet) and 1320 (3 by 11 feet) trees per acre
Quality nursery stock
Single rows of tall narrow canopies
Canopy shape that complements natural tree form
Minimal branching structure
Simplified pruning and training tasks
Planting dwarf apple trees and adopting practices such as minimal pruning and simplified training is a key step toward labor efficiency. Older training systems that were designed to facilitate mechanization, such as the Tatura trellis, were developed to facilitate shake-and-catch harvest, but this method was abandoned by engineers for use on large-fruited species such as apple and peach because it results in unacceptable levels of bruising. Other systems were developed to create pedestrian orchards for labor efficiency, such as the Penn State Low Trellis Hedgerow and the Lincoln Canopy. These training systems failed to catch on because tree training was intensive and required skill, and the extreme pruning and horizontal bending necessary for restricting canopy height often led to excessive vegetative growth and shading. In order to be economically productive, the orchard needs to achieve high light interception without creating dense areas in the canopy. Over time horticulturists found that when an orchard system is entirely within the reach of a person on the ground one of two bad things happens. Either a) the canopy is productive but too dense, causing a loss of fruit quality, or b) the canopy is too small, causing loss of yield. The solution has been to increase canopy volume without condensing the canopy by growing the tree taller, while keeping it narrow and orienting the rows in a north-south direction wherever possible to minimize cross-row shading.
While these tall narrow canopies satisfy both the interception and distribution requirements for light, increasing tree height reduces labor efficiency because it introduces the need for ladders. The tree height problem can be addressed with labor platform technology. Orchard platforms were tried in the past, but failed to save time because the orchard systems they were applied in consisted of larger trees and more distant spacing. With the new narrow fruiting wall systems we can achieve horticultural and technological compatibility:
The tall narrow tree wall is horticulturally sound, and its biological efficiency surpasses the performance of most existing systems.
Sunlight and labor have the same reach. Light becomes limiting after penetrating a fruit tree canopy to a depth of about three feet. With narrow canopies, we have addressed both problems of light distribution and platform labor reach simultaneously.
Tree height creates a simple labor access problem with an engineering solution.
Our proximity to the world’s most important fruit market (the U.S. east coast) is a growing competitive advantage for our industry, not only in transportation costs, but also due to growing consumer preference for locally-grown produce. The future for our fruit industry seems bright, except for the growing cost and scarcity of farm labor. The aim of a Penn State NRCS Conservation Innovation Grant (CIG) project (now in its fourth year) is to develop growing systems and technologies that will allow greater mechanization and labor efficiency in the short term, and fully automated systems in the future.
In twelve 1-acre CIG pilot plantings we are evaluating the effect of two high density apple growing systems on productivity, fruit quality, and labor efficiency. These training systems utilize the same support system, and trees are planted at the same spacing (691 trees per acre). The trees are being trained to form either a continuous tree wall, or as cone-shaped canopies with discrete gaps in the tree tops. Two popular varieties, one with high vigor (Cameo) and one with low vigor (Honeycrisp) are being used to determine if a difference in tree vigor level influences the performance of these systems based on fruit quality and labor efficiency. Labor efficiency between the two systems is being compared using both ladders and a mobile platform. The large number of CIG trials and the relatively large size of the plantings will also provide adequate space for evaluating additional labor saving technologies developed through two USDA Specialty Crop Initiative projects funded in 2008. By blending this research into the CIG demonstration project, we can increase the visibility of the results and speed industry adoption of new practices as they develop.
- Associate Professor of Pomology