Rooting Characteristics and Canopy Responses to Drought of Turfgrasses Including Hybrid Bluegrasses

Drought stress is common among cool‐season turfgrasses during summer in the U.S. transition zone. A 2‐yr field study was conducted near Manhattan, KS, to evaluate rooting characteristics and effects of drought on canopy physiology and appearance of ‘Apollo’ Kentucky bluegrass ( Poa pratensis L.) (KBG), ‘Dynasty’ tall fescue ( Festuca arundincea Schreb.) (TF), and two hybrid bluegrasses (HBG) ‘Reveille’ and ‘Thermal Blue’; HBG are genetic crosses between native Texas bluegrass ( P. arachnifera Torr.) and KBG. Rooting characteristics were measured in the field and greenhouse under well‐watered conditions to evaluate root contributions to drought avoidance. Two irrigation treatments in the field included: (i) 60% (water‐deficit); and (ii) 100% (well‐watered) evapotranspiration (ET) replacement. Ninety to 96% of all root length (0–80 cm) in the field and 74 to 80% of all root length (0–120 cm) in the greenhouse were in the upper 30 cm among Thermal Blue, Reveille, and KBG while in TF, only 86 and 70% of all root length in the field and greenhouse, respectively, were in the top 30 cm. In the field, tall fescue had 3 to 12 times greater root length in the lower profile (60–80 cm) among turfgrasses. Visual quality and gross photosynthesis (P g ) were greatest in TF among turfgrasses in both irrigation treatments. Reveille used more water from the 0 to 50 cm profile and performed better than Thermal Blue during water‐deficit, but both HBG recovered from water‐deficit slightly faster than KBG. Performances in visual quality and P g generally ranked: TF > Reveille ≥ Thermal Blue = KBG.