Establishment of a non-dormant blueberry (Vaccinium corymbosum hybrid) production system in a warm winter climate

Abstract

Summary‘Gulf Coast’, ‘Sharpblue’, and ‘Wannabe’ southern highbush blueberry (Vaccinium corymbosum interspecific hybrid) cultivars were planted at a density of 10,000 plants per ha in southwest Florida to test the feasibility of a non-dormant blueberry production system. A non-dormant production system involves application of nitrogen (N) throughout the fall and winter, which enables the plants to avoid the normal dormancy cycle and the concomitant chilling requirement. If successful, this system could extend the production range of blueberry into subtropical and tropical areas where chilling temperatures are inadequate for traditional (dormant) production systems. Nitrogen fertilizer rate (84 to 252 kg ha–1 N in year 1, 168 to 336 kg ha–1 N in year 2) was evaluated for effects on maintaining plant growth and development in this system. Additionally, since organic soil amendments are known to improve blueberry growth, the effects of municipal solid waste (MSW) compost and acidic peat on maintaining growth were also evaluated. In general, increasing N rates from 84 to 252 kg ha–1 (year 1) or 168 to 252 kg ha–1 (year 2) increased plant canopy volume, leaf retention, and rate of new vegetative budbreak. There was no consistent effect of N rates on soil nutrient concentrations, but leaf N increased and leaf Ca decreased as N rate increased. MSW compost incorporation increased P, Ca, Mg, Cu, Fe, Mn, and Zn soil concentrations compared with peat, but had no consistent effect on leaf nutrient concentrations. Plant height and canopy volume were consistently greater for plants grown in the MSW compost compared with the peat amendment, but there were no differences in leaf retention or vegetative budbreak between the two soil amendments. Plants in this non-dormant system have shown no deleterious growth effects, suggesting that establishing a blueberry planting in a warm winter climate is feasible under the described conditions.