Effects of Reclaimed Water Irrigation on Nutrient Management and Fruiting in Blueberry Production Systems

Increasing pressure on freshwater resources has heightened interest in reclaimed water (RW) as an alternative irrigation source for agriculture, yet its elevated salinity and variable nutrient composition may influence nutrient dynamics and crop performance in salt-sensitive species such as blueberry (Vaccinium corymbosum L.). This study assessed the short-term effects of RW irrigation on substrate nutrient status, nutrient leaching, and fruit production in a 10-month greenhouse experiment using groundwater (GW) and RW from two treatment plants (RW1 and RW2) applied to mineral soil, pine bark, and a 1:1 soil–pine bark mixture in a split-plot randomized complete block design. RW1 and RW2 were diluted 1:1 with GW; all water sources were adjusted to pH 5.5 before application. Relative to GW, NH4+–N in soil increased by 203% under RW1, and B and Mo concentrations in pine bark increased by 23% and 35%, respectively. Fruit number and weight were influenced by the substrate × water source interaction, although Tukey-adjusted pairwise comparisons did not identify significant differences among treatments. Irrigation water source did not affect cumulative NH4+-N, NO3−-N, or PO43−-P leaching losses. This study evaluated diluted RW in containerized plants under greenhouse conditions; therefore, findings should not be directly extrapolated to field production systems.