SportsTurf provides current, practical and technical content on issues relevant to sports turf managers, including facilities managers. Most readers are athletic field managers from the professional level through parks and recreation, universities.
Issue link: http://read.dmtmag.com/i/306114
20 SportsTurf | May 2014 www.sportsturfonline.com Field Science | By Dr. Nick Menchyk, Dr. Dara Park & Dr. Haibo Liu T urfgrass managers are always trying to leverage acceptable conditions with minimal inputs (water, nutrients, and pesticides). Maintaining optimal plant nutrition is the foundation of sustaining healthy turf- grasses that require fewer inputs. Liebig's Law of the Minimum states that plant growth is controlled not by the total amount of resources (nutrients) available, but by the most scarce resource (limit- ing factor). Due to the fertilization of macro and most micronutrients, this principle isn't usually a problem. However, there are trace micronu- trients that play critical roles in the plant that we should consider, such as nickel (Ni). Nickel constitutes approximately 3% of the earth's crust and is the 24th most abundant element. Nickel is a trace micronutrient that was discovered to be essential for plants in the 1980s. Typical ranges of Ni in soils range from 5-500 ppm; however, measuring bioavailability in soils is difficult because the plant available form Ni2+ readily oxidizes in the soil rendering it unavailable. Nickel is commonly forgotten in the world of turfgrass nutrition because of the low concentration found in plants (0.05-10 ppm) which is thought to be adequately provided by the soil. However, Liebig should not be disregarded when it comes to Ni and turfgrass. Nickel bioavailabiliTy Sports turf grasses are commonly grown in conditions conducive to reduced bioavailability of Ni: • Dry and/or cool soils in early spring, (Common throughout the Carolinas) • Soil pH > 7, (Limestone based calcareous sands, which are com- monly used for turfgrass root zones typically have pH values in the 8.2 range • Sandy and or low CEC soils (Putting greens, tees, and frequently top-dressed playing surfaces) In addition, the following management factors influence Ni bio- availability: • The presence of root-knot nematodes (Meloidogyne sp.) (Root- knot nematodes are not as damaging to turfgrass as sting or lance nematodes but are still commonly found in soils and can contribute to reduced Ni bioavailability) •Exceedingly high concentrations of Zn, Cu, Mn, Fe, Ca, and Mg, (Rooney et al., 2007; Wood et al., 2006) (Many constructed root zones are derived from calcareous sands. Additionally, liming materials and other Ca sources (gypsum) are commonly applied in turfgrass manage- ment increasing Ca in the root zone) • Ni deficiency was triggered in pecan with foliar applications of Fe, and heavy early spring application of N. (Turfgrass managers com- monly fertilize with both of these nutrients to correct deficiencies and improve turf color.) Ni ToxiciTy, deficieNcy, hyperaccumula- TioN, aNd plaNT defeNse Minimal information exists on Ni toxicity and deficiency for turf- grasses. However, by way of other plant research, we can make some conclusions about Ni. One of the most well documented Ni deficiency cases has been in pecan trees, in which the deficiency caused a disruption in carbon metabolism resulting in stunted growth leaves termed "mouse ear." Foliar sprays of Ni corrected the deficiency, but only in newly emerged leaf tissue. The diagnosis and management has brought to surface the importance of Ni in plant health and suggests the possibility that many horticulture crops may possess a "hidden hunger" for Ni. Plants found growing on serpentine soils containing elevated levels of metals (Zn, Cu, Co, Fe, Cr, Mg, and Ni) can hyperaccumulate Ni without deleterious effects. Nickel hyperaccumulator species have been studied for their potential in the phytoremediation of soils contami- These two photos show reduced growth with increasing Ni treatments from Clemson's toxicity study. Each one shows four representative plots of either Diamond zoysiagrass or TifEagle bermudagrass under Control, 400, 800, and 1600 uM Ni treatments. The reduction in clipping yield is significant and easy to see. Nickel aNd TurFgraSS growTh: all you Need To kNow