Thousands of acres of orchards were recently planted at high densities of 1000-2000 trees per acre. A project conducted last year in these intensive orchards gave rise to questions about control of tough perennial weeds like horsenettle, bindweed and Canada thistle. We also had challenges with the ground cover establishment strategies. Glyphosate and 2-4,D are typically used for control of perennial weeds, but the new concerns for glyphosate use in orchards raises the question of pre-plant control of perennial weeds before establishing the orchard. The driving factors for this project include simazine and glyphosate-resistant weeds, potential groundwater pollution with older herbicides, the newly reported risk of glyphosate application resulting in bark injuries and tree death, and the concern for soil health in orchards with such restricted root systems. This project will build on Cornell research on semi-dwarf systems to the more intensive high density systems and measure the impact of 6 ground cover treatments between trees and up to 14 herbicide strategies on tree growth, tree health, and soil health. With the help of 2 growers, 2 on-farm demonstration sites will be used to evaluate the sustainability of treatments in replicated plots for a second year, and provide a foundation for future research funding for a longer term. These two sites will serve as educational centers to evaluate various ground cover and herbicide strategies over a longer term. Results from this project will be disseminated to the conventional and organic grower though multimedia, presentations, publications, and featured on grower tours.
Project objectives from proposal:
The goal of this project is to adapt the Cornell research on semi-dwarf systems to the more intensive high density systems and measure the impact of 6 ground cover treatments between tree rows and up to 14 herbicide strategies on tree growth, tree health, and soil health.
Performance target 1: Evaluate various herbicides for number of days after application for post-emergent followup, and the number of post-emergent control applicaitons needed for the season.
Apply 14 herbicide treatments (3 replicates) in 1-yr established and 2-yr plantings in same plots as 2011. Manage plots using post-emergence herbicides as needed to hold %weed cover to <30%.
Performance target 2: Identify a prospective orchard planting site at each of 2 original farms, identify perennial weed issues, and use weed control resources for multiple commodities to address these weeds before the trees are established.
Performance target 3: Identify pros and cons of Ground cover options for between tree rows.
Manage 3 replicates of each of 6 ground cover treatments established in 2011 in newly and 1-year planting. Evaluate stand establishment, and determine growth rate and frequency of specific ground cover types.
Initiate a new set of ground cover plots at a third site.
Performance target 4: Evaluation.
Evaluate weed control in tree row.
Evaluate ground cover treatments between rows, % stand, % weeds.
Measure tree caliper growth to compare differences in treatments.
Measure soil health parameters.