Kentucky Bluegrass Growth and Quality as Affected by Salt Type and Concentration

Abstract

Core Ideas Salinity adversely affected Kentucky bluegrass growth and performance. Chloride salts were more detrimental to Kentucky bluegrass than sulfate salts when applied at the same electrical conductivity. Kenblue had a higher growth rate than Moonlight’under the saline condition at the seedling stage; however, Moonlight outperformed Kenblue at the vegetative growth stage. The growth and functionality of turfgrasses are often challenged by high soil salinity. Previous research mainly focused on plant responses to Cl− salt–induced saline conditions (e.g., NaCl). However, in some regions, including California and North Dakota, in salt‐affected soils the predominant cation is Mg2+ and the predominant anion is SO42−. The responses of turfgrass species to such salinity conditions have not been well documented. In this research, the responses of Kentucky bluegrass (Poa pratensis L.) cultivars Kenblue and Moonlight at the seedling growth and the vegetative growth stages to different salt type (NaCl, Na2SO4, MgCl2, and MgSO4) and concentration (5–20 dS m−1) were investigated. Results showed that shoot dry weight (SDW), root dry weight (RDW), root length (RL), and visual quality of the two turf cultivars decreased with increasing salt concentration at both growth stages. Specific root length increased to 235.7% of the control at the seedling growth stage but decreased to 71.6% of the control at the same salt concentration at the vegetative growth stage. Under the saline condition, Kenblue showed higher SDW (52.1%), RDW (74.4%), and RL (20.6%) than Moonlight at the seedling growth stage; however, Moonlight performed better than Kenblue at the vegetative growth stage. The two turf cultivars were more tolerant to Na2SO4 and MgSO4 stress than to NaCl and MgCl2 stress. Our research indicates that turfgrass managers need to consider plant material (cultivar and growth stage), salt type, and salt concentration to develop a successful salinity management plan.