Effect of nitrogen and potassium on the micro-nutrient content of fifteen bermudagrass cultivars

Information concerning the mineral nutrient composition of various turfgrass species and cultivars is limited. The concentration of nutrients in the turfgrass plant provides an indication of the overall nutrient status and quality of the turf stand. Bermudagrass [Cynodon dactylon (L.) Pers.] is an important turfgrass utilized throughout the Southeastern and Southwestern states and the transition zone of the United States. A study was conducted to determine the effects of different rates of nitrogen (N) and potassium (K) on the macronutrient content of fifteen bermudagrass cultivars. The cultivars utilized were: 'Ormond', 'Texturf 10', 'Tiflawn', 'Tufcote', and 'U-3'; 'Everglades', 'Midiron', 'Midway', 'Pee Dee', 'Santa Ana', 'Tifdwarf', 'Tifgreen', 'Tifway', and 'Tifway II' [Cynodon dactylon (L.) Pers. x Cynodon transvaalensis Burtt-Davey]; and 'Sunturf' [Cynodon magennisii Hurcombe]. Cultivar plots were replicated three times and were divided into four sub-plots for the application of N and K monthly from July to October, 1996 at rates of 227 g N and K 93 m-2 (low rates) and 454 g N and K 93 m-2 (high rates). The four N:K treatments were: (i) high N:high K; (ii) high N:low K; (iii) low N:high K; and (iv) low N:low K. Plant tissue samples were collected in late August and analyzed for N, K, phosphorus (P), calcium (Ca), magnesium (Mg), and sulfur (S). The high N:low K treatment was the only one to result in differences of N content among the cultivars. There were differences in P, K, Ca, Mg, and S content among the cultivars under each of the four treatments. The N, P, and S contents for all cultivars under all treatments were within the sufficiency ranges for these elements while K, Ca, and Mg contents were less than the lower value of the sufficiency range for these three elements for some cultivars under certain treatments. The content of K for most cultivars was toward or below the low end of the sufficiency range regardless of the high or low K rates.