Impact of potassium sulfate salinity on growth and development of cranberry plants subjected to overhead and subirrigation

New recommendations in cranberry production suggest reducing overhead irrigation and the use of subirrigation as an alternative irrigation method, two strategies suspected to increase the risk of salt buildup in soil. Because very little is known about cranberry tolerance to salinity, this study was conducted to determine if deficit irrigation and subirrigation could cause salinity issues and affect plant yield. In a greenhouse, cranberry plants were submitted to eight different treatments combination from two irrigation methods (overhead irrigation and subirrigation) and four salinity levels created by increasing amounts of applied K2SO4 (125 (control), 2500, 5000, and 7500 kg K2O ha(-1)). Irrigation methods showed no significant difference in measured electrical conductivity of soil solution (ECss). Meanwhile, growth and yield parameters decreased significantly with soil salinity in both irrigation treatments, and an average ECss of 3.2 dS m(-1) during flowering caused a 22% drop in relative photosynthetic rate and a 56% decrease in yield when compared with the control. Cranberry seems to be salt sensitive, and further work should investigate ECss levels under different field and irrigation practices to make sure that it does not reach critical levels.