Ubiquitous Chlorine Performs Vital Tasks In Turf

Although chlorine (CI) is the most abundant micronutrient in most plant tissues, Turner and Hummel (1992) reported that "deficiency symptoms or beneficial responses of turfgrasses to Cl have not been reported." This apparent inconsistency reflects the simple fact that Cl is ubiquitous in nature, and deficiency symptoms are never observed in turfgrasses or any other plants. It was not until 1954 that Broyer and his colleagues reported the general requirement of plants for Cl (Broyer et al. 1954). They were able to demonstrate Cl deficiency symptoms in plants only after filtering the air entering their Berkeley, Calif., greenhouses and growing plants on nutrient solutions prepared with doubly recrystallized salts to remove all Cl. While the Cl content of plant tissues normally ranges between 2 to 20 millograms per gram dry matter (parts per thousand), the Cl content required for optimum growth is in the range of 0.2-0.4 mg/g (Marschner, 1995). Apparently there are no data on the specific Cl requirements of turfgrasses, but it is unlikely their needs are different from those of most other plants. Since a Cl insufficiency is not likely, the turf manager need be little concerned about supplying this nutrient, but that does not mean it is unimportant.