DEVELOPING ORGANIC STONE-FRUIT PRODUCTION OPTIONS FOR UTAH AND THE INTERMOUNTAIN WEST UNITED STATES

Fruit production in Utah and throughout the US Intermountain West has come under increasing pressure due to rising input costs, diminishing water supplies, loss of export markets, and urban encroachment. These challenges also present considerable opportunity in the form of increased local and value-added marketing potential. Organic production may help growers to access new markets and cut production costs through enhanced synergies between ecosystem services and production goals. A peach (Prunus persica) orchard was established in 2008 with six organic treatment combinations: 1) straw mulch and grass alleyway; 2) straw mulch and legume (birdsfoot trefoil, Lotus corniculatus) alleyway; 3) living mulch (low-growing shallow rooted alyssum, Lobularia maritime) and grass alleyway; 4) living mulch and legume alleyway; 5) woven plastic mulch and legume alleyway; 6) tillage and grass alleyway. Paunch manure compost was applied at a baseline rate of 25, 48 and 96 g total N per tree in the first, second and third years of establishment and adjusted up or down relative to the baseline rate against tree growth. Tree growth as measured by trunk cross sectional area was initially slowed in living and non-living mulch treatments; by the end of 2011, trees were largest in legume alleyway treatments despite considerable tree row weed pressure. The ultimate goal of the research was to quantify the benefits and/or tradeoffs between different organic management scenarios on water use, pest dynamics, and fruit and soil quality in order to assist growers in making both economically and environmentally sound organic management practice decisions.