Davenport, J.

Joan Davenport

Building soil quality, enhancing soil microbial function, and alleviating chlorosis in Concord grapes with inter-row cover crops

Leaf yellowing, or chlorosis, occurs on more than 50% of the Concord vineyards in central WA, resulting in significant reductions in vine size, uniformity, productivity, and eventually vine death. The yellowing of the leaves resembles classic Fe-deficiency chlorosis, however many studies have attempted without success to determine the precise cause and effective treatment of this […]

Monitoring Uptake of Legume N by Apple Trees Using Nitrogen Isotope Discrimination

Intercropped legumes can supply nitrogen to fruit trees and reduce the need for purchased nitrogen fertilizer, potentially reducing costs and environmental footprint. The project evaluated nitrogen isotope techniques (comparing the 15N and 14N signal from the legume N versus other sources) to monitor the degree of uptake by apple trees of legume N grown in […]

Growing nitrogen in the organic orchard

Two on-farm trials were established in 2008 to test different approaches to growing nitrogen within an orchard. The trial at Warren Morgan Orchard (WMO) compared four perennial legume species (ladino white clover, alfalfa, birdsfoot trefoil, kura clover) direct seeded into the existing alley vegetation with or without suppression. All species were successfully established, with better […]