U.P. Hedrick Award Winner 2011: Alternative Alleyways for Tart Cherry Orchards

Abstract

Current commercial orchard floor practices in the U.S. Intermountain West consist of a grass alleyway and a vegetation-free strip in the tree row. Leguminous cover crops in the alleyway may provide the orchard with additional nitrogen inputs. Alleyway treatments of alfalfa ( Medicago sativaL.), alfalfa-clover mix ( Trifolium fragiferumL., and T. repensL.), birds-foot trefoil ( Lotus corniculatusL.), black medic ( Medicago lupulinaL.), hairy vetch ( Vicia villosaRoth), and a commercial standard grass mix were compared in a mature tart cherry orchard for stand establishment, biomass production, water use, and nitrogen content. A subset of these treatments was also tested in a newly planted tart cherry orchard, and evaluated for stand establishment and weed suppression. Results show that alfalfa, alfalfa-clover mix, and hairy vetch had the best stand establishment at 92.3, 94.6, and 91.5% cover, respectively, comparable to the existing grass alleyway at 91.7%. Alfalfa and alfalfa-clover mix produced the most biomass at 5.28 and 4.53 T·ha ^-1, respectively. However, water use exceeded 5.60 mm·d ^-1compared to 2.59 mm·d ^-1for the grass treatment. Birds-foot trefoil did not establish very well and did not suppress weeds significantly. Based on above-ground biomass production and nitrogen content, total potential nitrogen contribution from an alleyway cover of alfalfa would be 143 kg·ha ^-1.