Severity of Sanding or Pruning Impacts Yield and Microclimate of Cranberry Vines

Sanding and pruning are two practices used in the cranberry (Vaccinium macrocarpon Ait.) industry for vine management and yield stimulation.  This study compared the effects of varying levels of sanding and pruning in April 2006 on vine canopy characteristics and yield over the course of two growing seasons.  Each practice was applied at four levels: sanding application directly onto the vines at four depths: control (0 cm), light (1.5 cm), moderate (3.0 cm), or heavy (4.5 cm); pruning at four severities with a commercial pruner: control (not pruned), light (1 pass with pruner), moderate (2 passes), and heavy (3 passes).  Pruning levels had no effect on upright density over the two seasons, but the heavy sanding treatment decreased the number of uprights per unit area significantly.  A linear increase in light penetration to soil level was observed for the first season only as severity increased for both pruning and sanding.  Number of fruiting uprights relative to total uprights decreased in the first year as severity increased for both practices.  This effect continued in the second year for sanding treatments.  Yield and net returns averaged over the 2 years were greatest in lightly pruned plots, followed by lightly sanded plots.  Moderate and heavy treatments were associated with lower yields and net returns than those for the controls.