Management practices for optimal kikuyugrass quality and playing conditions.
Kikuyugrass [Cenchrus clandestinus (Hochst. ex Chiov.) Morrone] is considered either an invasive weed or the desired species on many golf courses, athletic fields, and other turf areas along coastal and inland California. A field study was conducted at the University of California, Riverside in 2012 and 2013 on 'Whittet' kikuyugrass mowed at 11 mm to identify management practices for producing sufficient turf quality and optimal playing conditions for golf course fairways and athletic fields. The study evaluated the effect of mowing frequency (three vs. six times per week), cultivation practice (verticutting vs. grooming), applications of trinexapac-ethyl (TE), and nitrogen fertilization rates (96 vs. 240 kg N ha-1 yr-1) on turf quality, Normalized Difference Vegetation Index (NDVI), turf firmness, ball roll distance (BRD), and tensile strength. Mowing six times per week produced the highest turf quality turf during summer when kikuyugrass grows most vigorously, while trends were not clear for cultivation practice effects on turf visual quality. However, verticutting twice per year produced the least scalped and firmest turf, while decreasing BRD. Application of TE increased turf quality, NDVI, and BRD, but decreased tensile strength of the sward. Slightly higher turf quality was detected in plots fertilized at 240 kg N ha-1 yr-1 compared to those fertilized with the low N rate (6.0 vs. 5.8), but results do not seem to justify higher N fertility. Overall, results demonstrated that kikuyugrass available in California could benefit from high input management practices such as TE applications, high mowing frequency, and verticutting.