Title: The Effect of Pre-plant Incorporation with Sawdust, Sawdust Mulch, and Nitrogen Fertilizer Rate on Soil Properties and Nitrogen Uptake and Growth of

The effect of incorporated sawdust, sawdust mulch and nitrogen (N) fertilizer rate on soil nutrients and other properties, N uptake, and plant growth in a young blueberry planting on a silt loam soil type was studied in 2004 and 2005. ‘Elliott ’ highbush blueberry plants were established on raised beds that were either constructed with the incorporation of a fir sawdust amendment, or left un-incorporated. Plots were then mulched with sawdust or left bare after planting. Nitrogen fertilizer, depleted 15N ammonium sulfate, was applied at three rates, 22, 68, and 114 kg·ha-1 of N in the first year, with non-labeled N fertilizer applied in the second year at the same rates. There was a wider range in soil temperature in plots incorporated with sawdust and mulched, from-2 ºC in winter to 41 ºC in summer, than in un-mulched plots. Sawdust mulch did not appear to mitigate summer or winter soil temperatures. Incorporated plots required 5-6 times more irrigation water than non-incorporated plots during the growing season. Soil pH was reduced with higher rates of application of fertilizer N, but incorporating sawdust or mulch minimized the reduction in pH. Soil phosphorus concentration was reduced in incorporated plots