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than one method (Mehlich II and III, DTPA) can be used to extract micronutrients from soil and results often vary from one method to the next. After testing soil, very specific recommendations may be made regarding the application of individual micronutrients (Table 1). Interestingly, it is not uncommon for turfgrasses to respond favorably to an application of Fe even though a soil test report indicates that the concentration of the micronutrient is in the high range. An analysis of plant tissue is recommended as a supplement to soil testing. Micronutrient levels in turfgrass tissue are usually reported as ppm on a dry-weight basis. For example, bermudagrass turf is often considered nutrient deficient if shoot tissue contains less than 100 ppm Fe, 30 ppm Zn, 25 ppm Mn and 10 ppm Cu on a dry-weight basis. Information regarding specific micronutrient sufficiency ranges for individual turfgrass species or varieties is limited, however general or common sufficiency ranges have been published (Table 2). Possibility of a micronutrient deficiency Some micronutrients are more apt to be at low or deficient levels than others. A deficiency of Fe in turfgrasses maintained out of doors is much more common than a deficiency of the other micronutrients. Iron deficiencies are most likely to occur in poorly rooted and thatchy turfs maintained in calcium-rich soils with high P and pH (> 7.5) levels, and very little organic matter. Turfgrasses irrigated with water high in bicarbonates, P, Ca, Cu, Mn or Zn may also be deficient in Fe. Although less commonly observed than a Fe deficiency, a Mn deficiency in turfgrasses is not unusual. A Mn deficiency, like that of Fe, may occur in plants maintained in soil with a high pH and Ca level. Extended periods of dry, warm weather reduce Mn availability in soil. Boron, Cu, Mo and Zn deficiencies are rare. High levels of Ca in soils can reduce the availability of B. Boron deficiencies are also more likely to occur in turfgrasses growing in porous, sandy soils with a high pH and high level of K. Since Cu can tightly bond with soil organic matter, deficiencies of Cu have been observed in turfgrasses growing in organic soils. Copper deficiencies have also occurred in turfgrasses maintained in sandy and alkaline soils, and soils with high www.landscapeirrigation.com N, P, Fe, Mn, Zn or pH levels. Molybdenum deficiencies are more prevalent in turfgrasses growing in acidic and sandy soils. High levels of S, Cu, Fe and Mn may limit the amount of Mo turfgrasses absorb from soil. Zinc deficiencies have occurred more often in turfgrasses in shade, in alkaline or acidic soils, and during cool, wet weather. At present, no Cl or Ni deficiencies have been documented in turfgrasses. Once inside a turfgrass plant, some micronutrients are much more mobile than others. Iron and Mn are immobile and Cl is mobile in turfgrass plants. Boron, Cu, Mo and Zn are somewhat mobile. The location of a deficiency symptom on a turfgrass plant is influenced by nutrient mobility. For example, due to the inability of a turfgrass plant to move the micronutrient from older to younger leaves, symptoms of a Fe and a Mn deficiency occur first on young leaves. Leaf tissue between veins of young leaves of a plant deficient in Fe often turns yellow then white. This condition is commonly referred to as interveinal chlorosis. The youngest leaves of a plant deficient in Mn usually develop small grayish-green spots before the leaf tips and the tissue between veins turn yellow. Turfs deficient in Mn often appear mottled. Young leaves of a turfgrass plant deficient in B may have yellow or white leaf tips and exhibit interveinal chlorosis long before older leaves. The margins of young and middle-aged leaves of plants deficient Landscape and Irrigation 11