Dr Phillip Ford
Agronomist, Melbourne Polytechnic
What are the 10 main differences between C4 (warm season turf grasses) and C3 (cool season turf grasses)
Water restrictions during the millenium drought demonstrated the vastly superior drought resistance of C4 turfgrasses such as couch and kikuyu, compared to C3 turfgrasses such as perennial ryegrass. Simply put, irrigation of a couch sward in south-eastern Australia is optional; its survival is not threatened by drought. In contrast, around 8 ML/ha per summer needs to be budgeted to sustain life and acceptable quality on a perennial ryegrass field.
The C4 photosynthetic pathway accounts for a 25-30% reduction in irrigation requirement, but the vastly superior drought resistance of a C4 turfgrass goes well beyond that. This is due to a combination or interaction of several factors, such as tolerance to high foliage temperatures and high root growth and functionality through the summer. These differences aren't just physiological, they affect the safety and playability of sporting fields as well. It is important that Parks Managers be reminded of these points, as it is only a matter of time until the next drought crisis - not to mention climate change, and increasing water costs.