Organic pear growers must balance the conflicting pressures between nitrogen levels and densities of pear psylla, a nitrogen-loving pest of pears. We are assessing in 3 certified organic orchards and 1 experimental orchard whether planting of alfalfa leads to improved tree nutrition and biological control of psylla. Alfalfa was planted in 2 ft wide strips […]
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 […]
Sustainable methods of nitrogen (N) fertility and weed management in organic production systems remain a challenge. Composted animal manures are commonly used to supply N, but only a fraction is in immediately available forms with the remainder released slowly as a result of microbial driven processes. These amendments come at a high cost, and excess […]
Cover crops are a locally grown source of organic matter and nitrogen and a weed management tool. Despite these benefits, many organic farmers have not been able to work cover crops into their management systems. We are evaluating different cover cropping systems, to help organic farmers determine how to best use cover crops on their […]
Two three-year rotations are being investigated for suitability for organic transition in northwestern Washington. Cover crop growth was greater and resulted in better weed suppression during 2004-05 than in 2003-04. Common chickweed was the major winter weed species, accounting for 90% of the total weed biomass during the first winter and 75% during the second. […]