Evaluation of Fall Applied Organic Based Nutrient Sources for Tree Fruit Production

Hebb, D., Embree C.
Agriculture and Agri-Food Canada, Kentville, Canada

Nutrient release and therefore availability is typically spread out or delayed in production systems with high levels of organic matter. This is especially true in organic production, where chemical fertilizers are not used and organic based nutrient sources are prominent. This can result in nutrients not being available in the year of application, or available late in the season. For nitrogen, this has a number of implications in tree fruit production, as late season nitrogen availability can negatively impact ripening and winter hardiness. Fall or pre-season application of organic based nutrients may provide for timely nutrient supply during the growing season and reduce the risk related to late season availability.

Three nutrient sources were evaluated for possible fall application: an organic pelletized poultry manure, a locally produced poultry layer compost and a standard ammonium nitrate fertilizer. Each product was applied in three treatments of 100% in the fall, 100% in the spring and a split application (½ fall and ½ spring) based on the same nitrogen application rate. Tree growth, fruit yield and quality were recorded for the two growing seasons of 2004 and 2005. Each year soil and leaf samples were analyzed for nutrients including nitrogen.

Tree performance has not been noticeably different among treatments, (2005 harvest data are required for final results). Analyzed results should show the risk and potential benefit for fall applied organic based nutrients in tree fruit production.