INFLUENCE OF CORE AERIFICATION, TOPDRESSING, AND NITROGEN ON MAT, ROOTS, AND QUALITY OF MEYER ZOYSIAGRASS

Thatch accumulation is a common occurrence in lawn and sports turf and is usually detrimental, We initiated aerification, topdressing, and N treatments in July 1987, to investigate their influence on thatch, ma t, quality, and color of zoysiagrass (Zoysia japonica Steud. cv, Meyer ). Turfgrass color responses to N were positive and strongly linear. T urfgrass quality was generally good to excellent in response to N. How ever, trends were not as well defined as color responses and varied ac cording to month and year. The aerification + topdressing combination according to N level was nonsignificant for turfgrass quality in all m onths and significant for color only in October, Weight of mat, which consisted mostly of rhizomes, and root weights declined linearly in re sponse to increasing N. The root weight response is consistent with re search reports of C-3 turfgrasses but inconsistent with earlier studie s of C-4 turgfgrasses where root weights increased with increasing N. Mat depth averaged over N was equal in response to topdressing vs. no topdressing. Root weights and mat weight were significantly greater wi th topdressing, Mat organic matter (OM) was greater with no topdressin g. Our results suggest that maintenance of zoysiagrass with only enoug h N to provide acceptable turfgrass density and color will give the be st root development in nonsandy soils. Annual topdressing with soil si milar to that of the growing site may further enhance root development .