Nitrogen fertilization and rates of glyphosate as growth regulators in zoysiagrass

Abstract

Nitrogen fertilization provides, in addition to nutrition, the maintenance of intense green color in ornamental turfgrasses, necessary undeesthetic viewpoint. But, nitrogen (N) increases the growth of shoots and, thus, the frequency of cuts, the main factor in the cost of turfgrasses maintenance. In this context, this study aim to evaluate nitrogen fertilization (via soil and foliar) and the use of rates of glyphosate as a growth regulator in zoysiagrass (Zoysia japonica Steud.) to maintain the visual quality (intense green) and good nutritional quality as well as reduce foliar growth. The research will be conducted at the Experimental Station of UNESP, Ilha Solteira/SP, from August/2014 to July/2017. It will be used a randomized block design with 20 treatments arranged in a factorial scheme 5 x 4 with four replications and 10 m2 per plot. The treatments will be: control (without N), 15 g m-2 of N in the soil without application of foliar N; 30 g m-2 of N in the soil without application of foliar N; 15 g m-2 in the soil with foliar application of N (1% urea) and 30 g m-2 of N in the soil with foliar application of N (1% urea) combined with four rates of glyphosate (0, 200, 400 and 600 g ha-1 active ingredient (a. i.). Will be evaluated: the chemical characteristics of the soil, height and dry matter of leaves, leaf area, ICF index (leaf chlorophyll), the chlorophyll a and b, the digital image analysis and the percentage of phytotoxicity of the shoot, beyond the occurrence of weed species and number of inflorescence, as well as the concentration and accumulation of macro and micronutrients by leaves of turfgrass and log-isometrics balance of nutrients in the leaves and cationic balance in the soil (isometric log ratio - ilr). Will be also assessed the root system (dry matter and macronutrients in roots + rhizomes). (AU)