Highlights From UC Riverside Field Day September 27, 2011 By Pat Gross

(L) A project investigating the ability of different warm season and cool season grasses to sequester carbon under deficit irrigation, and (R) a study evaluating different mowing, fertility, vertical mowing and growth regulator treatments on kikuyugrass, were highlighted recently at the UC Riverside Field Day.  



Dr. Jim Baird and staff hosted a very successful turfgrass research field day at UC Riverside on September 15th.  There were more than 200 people in attendance to see the latest in turfgrass research.  Thirteen different projects were highlighted ranging from fungicide trials to kikuyugrass maintenance and salinity management.  Research activity at UCR has steadily increased in recent years as noted by the five graduate students involved in various projects.  The following is a brief highlight of the studies in progress at UCR.

Evaluation of fungicides on creeping bentgrass under drought stress – Drought is one of the primary stress factors in the Southwest, and this study is evaluating the impact of various fungicides on sustaining healthy turf growth when subjected to severe water reduction and also evaluate the role the treatments play in turf recovery following core aeration.  The Intrinsic brand fungicides (Pillar, Honor, and Insignia), Daconil ACTion, and Interface controlled an unintentional outbreak of dollar spot during the study and also demonstrated the highest turf quality during the dry down process.  The core aeration part of the study is still under evaluation

Drought and salinity effects on perennial ryegrass – This study was initiated in July on a specially constructed plot with alternating lines of potable and saline water with the ability to apply different amounts of water ranging from deficit irrigation to leaching.  Preliminary results have shown a reduction in clipping yield and visual quality in the plots receiving the highest salinity water and less overall irrigation.  Salt concentrations of ≥ 5dS/m have caused turf damage.  So far, irrigation replacement of 100% to 140% of ETo appears necessary to sustain perennial ryegrass color and quality in the warm inland climate of Riverside.  In-ground moisture and salinity sensors will continue to monitor the impact of water quality and irrigation quantity through the duration of the study.

Carbon fixation and water use efficiency of warm and cool season grasses – Media reports have highlighted the concern about increasing levels of CO2 in the atmosphere.  This study is investigating the ability of various grasses to sequester carbon (C) when subjected to deficit irrigation.  As expected, the warm season grasses displayed the greatest water use efficiency.  Under deficit irrigation, Tifway bermudagrass showed the best water use efficiency of the warm season grasses and a blend of Kentucky bluegrass and perennial ryegrass (Bayside blend) was the best for the cool season grasses. Tifgreen 328 and Tifway II exhibited the highest C fixation potentials of the warm-season species while the Kentucky bluegrass/perennial ryegrass mixture was highest of the cool-season species.  An interesting outcome of the study to this point was that drought tolerance does not necessarily equate to greater water use efficiency or the ability to sequester more C as noted by tall fescue and buffalograss, two species with exceptional drought tolerance/avoidance among the cool- and warm-season turfgrasses that did not rank highest in the study thus far.

Kikuyugrass management practices – Love it or hate it, kikuyugrass is managed as the primary turf at many golf courses, parks and sports fields in California.  This study was initiated to look at the impact of different fertilizer, verticutting, growth regulator treatments, and mowing practices on the quality of kikuyugrass.  Although the study was only in its sixth week,  there was a clear visual difference in plots treated with Primo MAXX and mowed on a frequency of six times per week.  The overall impact of grooming and vertical mowing treatments is still being evaluated. 

Source: Pat Gross,