Effect of N Source, K Source, and K Rate on Soil Nutrient Levels and the Growth and Elemental Composition of Penncross Creeping Bentgrass, <i>Agrostis palustris</i> Huds.¹

Abstract

Abstract Relationships between soil nutrients, applied fertilizer, and turfgrass response are important in planning turfgrass fertilizer programs. A 4‐year study was conducted to determine the effects of five N sources (urea, Agrinite, Milorganite, Uramite, and Nitroform), two K sources (KCl and fritted potash), and three K rates (0, 1.2, and 2.4 kg/100 m 2 ) on soil nutrient levels and the growth and elemental composition of Penncross creeping bentgrass ( Agrostis palustris Huds.). Soil test levels, elemental content of clippings, and clipping weights were used to evaluate treatments. Soil P and Mg levels were significantly higher with Milorganite as the N source. KCl applications increased K levels and decreased Mg and Ca slightly, whereas fritted potash increased both K and Ca. Tissue analyses indicated highest N with urea as the N source, lowest N with Agrinite, and highest P with Milorganite. Added K increased K in the clippings and decreased N, Ca, Mg, Mn, and Na. Although K additions decreased some elements in the soil and clippings, the magnitude of these changes was not considered critical under the conditions of these experiments. Significant yield differences due to N source decreased over the years. In general, clipping weights were not influenced consistently by K source or K rate; however, significant increases due to K have increased with time.