The effect of organic and conventional management programs on apple and Asian pear tree growth, productivity, expenses and revenues in a hot, humid climate.

摘要

A one-hectare apple and Asian pear orchard was established in 2003 to compare the growth and productivity of trees under organic and conventional management systems. Trees planted in this plot were selected from three broad categories; conventional apple cultivars, disease-resistant apple cultivars and Asian pears. One plot in each of five blocks was managed using current conventional methods. The other plot was managed using approved organic inputs and certified by the Maryland Department of Agriculture (MDA). Trees survived and grew under both production programs but tree vigor and fruit yields were greater in the conventional plantings. We encountered four difficulties in managing the organic plots; (1) slow growth of young trees, (2) difficulty in controlling weed competition, (3) direct pests affecting the fruit and (4) reduced yields. A strong cultivar-by-treatment interaction on yield was measured in two apple cultivars and one Asian pear cultivar. 'Enterprise' trees were very productive under the conventional program but significantly less productive in the organic blocks. An economic analysis was conducted to compare the two management programs. This economic evaluation focused on farming practices and inputs that differed; pest control, nutrient applications, field labor operations and tree support. Organic production took more time than conventional production due to the labor required for weed control and the additional pesticide applications. A great difference in the relative system profitability was caused by the differences in yields from organic plots. Lower organic fruit yields appeared to be a greater barrier to profitability than the higher expenses required for chemicals or labor in the organic plots.