Field Evidence for Lateral Transfer of Water and Nutrients In Highbush Blueberry

Split-root studies done in the 1980’s on potted blueberry plants revealed that applying irrigation or fertilizer on only one side of the plant reduced growth and production on the other side, suggesting that blueberry has little ability to transport water and nutrients laterally within the plant.  However, this work was never verified in the field.  Thus, we initiated a field study in 2009 to determine if this was the case in a mature planting of ‘Elliott’ blueberry.  Plants were either irrigated on only one side or fertilized on only one side and compared to plants irrigated and fertilized on both sides.  Applying water to only one side reduced shoot and fruit production, while applying N fertilizer to only one side reduced leaf N.  However, shoot growth, yield, berry size, plant water potential, and leaf N were similar on both sides of the plant whether water and N fertilizer were applied to only one side or both sides.  Interestingly, plants naturally produced three times as many roots on the east side than on the west side of the row, which resulted in 1) greater root water uptake from the east side and 2) higher water status in plants only irrigated on the east side than in those only irrigated on the west side.  Likewise, leaf N status was higher when N fertilizer was applied on the east side than on the west side.  Blueberry may therefore benefit when proportionally more water and nutrients are applied on the row side with most roots.