THE EFFECTS OF GROUNDCOVER MANAGEMENT AND NUTRIENT SOURCE DURING ORGANIC ORCHARD ESTABLISHMENT

Abstract

Expansion of organic tree fruit production in the southern region of the USA has been hindered by lack of reliable, regionally appropriate, and scale-neutral technologies. In March 2006, an experimental organic apple orchard of 'Enterprise'/M26 was planted in a replicated trial to examine the effects of three organic fertilizer treatments (control, composted poultry litter and commercial pelletized fertilizer) and four groundcover treatments (shredded paper, wood chips, municipal compost and mow-blow), with the goal of developing organic management recommendations. The effects of nutrient and ground cover treatments on tree growth, canopy and root development, soil biological, chemical and physical characteristics, foliar nutrient content, and weed density were evaluated during the establishment period of the orchard as a precedent for cropping. This paper reports on the effects of these treatments on early tree growth, development, and physiology. Significant differences have been found among the organic production systems were observed after two seasons of growth. Trees grown with ground cover managed with compost or wood chips were larger than those using shredded paper or mow-blow. Both composted poultry litter and commercial fertilizer resulted in trees larger than trees which derived nutrition solely from the ground cover treatments without additional nutrients. In the third season, trees with compost or woodchip mulch had significantly more flowers, more harvested fruit, and higher fruit set than those grown with mow-blow or shredded paper. Trees that did not receive supplemental nutrition had significantly fewer flowers, fruit set, and harvested fruit, compared with those receiving poultry litter or a commercial fertilizer.