• Refine Query
  • Source
  • Publication year
  • to
  • Language
  • 1
  • Tagged with
  • 1
  • 1
  • 1
  • 1
  • 1
  • 1
  • 1
  • 1
  • About
  • The Global ETD Search service is a free service for researchers to find electronic theses and dissertations. This service is provided by the Networked Digital Library of Theses and Dissertations.
    Our metadata is collected from universities around the world. If you manage a university/consortium/country archive and want to be added, details can be found on the NDLTD website.
1

Nitrogen cycling in tall fescue turf with added clippings

Waddill, Dan W. 21 July 2009 (has links)
Grass clippings may be recycled onto nearby areas of turf as an alternative to disposal of clippings in landfills. In May, 1991, two field studies were initiated to evaluate grass clippings as a nitrogen (N) source for tall fescue (Festuca arundinacea, Schreb. Rebel’) turf, and to determine the maximum feasible loading rate of clippings onto tall fescue turf. Test plots in both studies received additional clippings from adjacent donor plots. In the first study, grass clippings alone were applied to 2.2 m² test plots at rates of 1 "plot equivalent harvest" (PEH), 2 PEH, and 4 PEH; where PEH is the amount of clippings harvested from 2.2 m² of donor plots. In the second study, test plots had clippings removed (Rem), clippings returned (Ret), Ret+1 PEH, and Ret+3 PEH. These four clipping treatments were arranged in a factorial combination with three fertilizer-N rates: low (73 kg N ha⁻¹ yr⁻¹), medium (147 kg N h⁻¹ yr⁻¹), and high (220 kg N h⁻¹ yr⁻¹). Donor plots received identical fertilizer-N applications as test plots. For both studies, N uptake generally showed a linear response to total N applied. Clipping-N produced roughly the same amount of growth and N uptake as the fertilizer-N, even as the rate of N uptake varied with time. In both studies, soil nitrate levels remained low until excessive clippings smothered the turf and caused a reduction in N uptake. Soil nitrate concentration tended to decrease with depth for all plots. Soil total Kjeldahl nitrogen (TKN) levels did not differ among treatments, suggesting that clipping-N was not being stored in the soil. At the end of both growing seasons, thatch accumulation was less than 12mm in all plots. In general, increased additions of clippings resulted in improved color, density, and growth. However, at the very high rates of added clippings, excess biomass caused turf thinning, chlorosis, and low growth. Thus, if grass clippings are applied at rates that are low enough to prevent these problems, they can be an effective N source for tall fescue. Furthermore, in order to dispose of the maximum amount of clippings, tall fescue should not be fertilized. / Master of Science

Page generated in 0.0391 seconds