Use of Pine Bark In Soil Management of Southern Highbush Blueberries (Vaccinium corymbosum, L)

Southern highbush blueberry plants (Vaccinium corymbosum hybrid) require acidic soils that are well-drained and have high organic matter content. Very few soils in Florida are suited for blueberry production without significant modification. As a result, blueberries are commonly planted on pine bark beds that are 15 to 18 cm deep and approximately 1 m wide and are situated on top of deep, well-drained, sandy soils. SHB blueberries are vigorous and productive on pine bark beds but typically require more water and fertilizer than when they are grown directly in soil partly because blueberry roots in pine bark beds are confined to the pine bark layer and do not typically grow into the underlying soil. Pine bark bed production systems may use up to 1,000 to 1,200 m³/ha of pine bark for establishment which represents a significant portion of the overall planting costs. A study was conducted at the University of Florida Plant Science Research and Education Unit, Citra, FL to examine methods of pine bark application with the goal of reducing pine bark inputs without reducing plant growth and fruit yield. Treatments consisted of 1) Non-amended soil; 2) 8 cm of pine bark incorporated into the top 15 cm of soil; 3) 8 cm of pine bark incorporated plus 8 cm of pine bark mulch; and 4) 15 cm deep pine bark beds on top of the soil.  Canopy volumes were smaller and berry yields were less for plants grown in non-amended soils than for plants in any of the pine bark treatments. However, few differences were observed among the pine bark treatments for canopy size, berry yield, or mean berry size. Our preliminary results suggests that alternatives to pine bark bed production such as soil incorporation of pine bark may result in reduced organic matter inputs without reducing plant growth or yield.