Department of Plant Sciences

A container experiment was conducted to simulate the raised bed cultivation system in upland blueberry production and to identify the major loss pathways of N from the root zone amended with different soil organic matter. Treatments were: PM -Tateyama brown forest soil + peat moss (1:1), SC – soil + sawdust sewage sludge compost (1:1) + ferrous sulfate, and SO – soil only. The response of each treatment to ammonium sulfate fertilization was remarkably different. The nitrous oxide emission was largest in the SO and PM treatments (0.41, 0.31 mg N2O/m2/hour, respectively) and lowest in the SC treatment (0.05 N2O/m2/hour) after fertilizer application. The drainage water nitrate concentration was relatively high in SO and PM (159 and 80 mg L-1 respectively) after fertilization. The highest cumulative berry fresh weight was recorded in SC (816 g) followed by PM (85 g) and SO (81 g). According to these results, the sawdust compost treatment may be most suitable due to lower environmental risks and higher yield.