Simulated traffic on turfgrasses during drought stress: II. Soil moisture, soil compaction, and rooting

Abstract

Turf is often subject to traffic stresses during drought. Our objectives were to evaluate the impacts of golf cart traffic applied during simulated drought on soil properties and turfgrass rooting. Soil and roots in the upper profile (0-30.5 cm) were evaluated in two cool-season (C 3 ) [Kentucky bluegrass (Poa pratensis L.) and perennial ryegrass (Lolium perenne L.)] and two warm-season (C 4 ) turfgrasses {buffalograss [Buchloë dactyloides (Nutt.) Engelm.] and zoysiagrass (Zoysia japonica Steud.)} maintained at golf course mowing heights (1.6 [fairway] and 6.3 cm [rough]) during a 41-d drought (with traffic) and subsequent 40-d recovery (without traffic). After drought, soil bulk density was ≤1.40 g cm −3 and generally below the 1.55 g cm −3 threshold, where root-growth restriction is more problematic. After drought, soil penetration resistance exceeded 2.0 MPa at lower depths, especially at fairway height, which may impede root-growth. The C 3 turfgrasses had 46-70% more root biomass and 150-290% more root length density than C 4 turfgrasses. However, only root diameter was correlated with turf canopy performance (r = 0.501; P < .001), which was 20-23% less in Kentucky bluegrass; a smaller root diameter may have diminished its ability to explore for moisture as soils dried. Most differences in soil and root characteristics resulted from drought and not traffic stress, since the traffic main effect was not significant. Results indicate cart traffic during acute drought may have negligible effects on soil compaction and rooting.

Simulated traffic on turfgrasses during drought stress: I. Performance and recovery of turf canopies

“…Interestingly, trafficked perennial ryegrass had as high of GC as the two trafficked C 4 turfgrasses at the end of the drought in 2015, while trafficked Kentucky bluegrass had considerably lower GC (18–22%) than the other three trafficked turfgrasses. In a companion paper (Braun et al, 2021), we reported that golf cart traffic during drought had a minimal impact on soil and root characteristics as a result of decreasing soil moisture of this same experiment. It was also found that the C 4 turfgrasses and perennial ryegrass had larger root diameters, which may have led to greater capabilities of exploring large volumes of soil, thus better drought performance.…”

“…Data were collected from 26 June to 18 Sept. 2015 and 23 June to 15 Sept. 2016 from two 1.8‐ by 0.21‐m areas (tire width = 0.216 m) within each 1.8‐ by 1.4‐m plot including nontrafficked treatment plots. To evaluate the impacts on soil from and the responses of roots to traffic applied during a drought period, soil and root measurements conducted prior to and after termination of the drought and recovery periods are discussed in a companion paper (Braun et al, 2021).…”

Review of cool‐season turfgrass water use and requirements: II. Responses to drought stress

“…During a 41‐d dry down with no irrigation or precipitation in Manhattan, KS, green cover generally remained higher in ‘Paragon GLR’ perennial ryegrass than ‘America’ Kentucky bluegrass including when golf cart traffic was applied (Braun et al., 2021). Those authors reported that better performance in perennial ryegrass was strongly correlated to its larger root diameter compared with Kentucky bluegrass (Braun, Bremer, & Hoyle, 2022). Root parameters were not measured below 30 cm in that study, but in a drought study in Columbia, MO (silt loam soil; warm temperate, no dry season, hot summer [Cfa] climate [Kottek et al., 2006; Rubel et al., 2017]), root mass was greater in ‘Manhattan’ perennial ryegrass than in ‘Fykling’ Kentucky bluegrass below 36 cm (Sheffer et al., 1987).…”