Date of Award:

11-2011

Document Type:

Dissertation

Degree Name:

Doctor of Philosophy (PhD)

Department:

Plants, Soils, and Climate

Advisor/Chair:

Kelly Kopp, Ph.D.

Abstract

This research investigated the water use of different plant types in urban landscapes, nitrogen (N) and water transport in turf, and potential N leaching from urban landscapes to ground water. In the first study, three landscape treatments integrating different types of plants—woody, herbaceous perennial, turf—and putative water use classifications—Mesic, Mixed, Xeric—were grown in large drainage lysimeters. Each landscape plot was divided into woody, turf, and herbaceous perennial plant hydrozones and irrigated for optimum water status over two years, with water use measured using a water balance approach. For woody plants and herbaceous perennials, canopy cover, rather than plant type or water use classification, was the key determinant of water use relative to reference evapotranspiration (ETo) under well-watered conditions. For turf, monthly evapotranspiration (ETa) followed a trend linearly related to ETo. In the second study, water transport parameters were calibrated using an inverse simulation with Kentucky bluegrass (KBG). Subsequently, those parameters were applied to simulate water use by tall fescue (TF) and buffalograss (BG) turfgrasses using numerical modeling (Hydrus-1D). By using the calibrated soil hydraulic parameters obtained from the water transport simulation, N transport and transformation was modeled with Hydrus- 1D under different irrigation rates and different fertilization rates. Different soil texture scenarios were also simulated to demonstrate the influence of soil texture on N leaching. In the third study, the simulated N-leaching from different soil textures was integrated into a Geographic Information System (GIS) approach to estimate NO3-N leaching mass from urban turf areas. Nitrate-N leaching risks to ground water under overirrigation and overfertilization scenarios and efficient irrigation and fertilization scenarios were estimated. The results showed improvement of turf irrigation and fertilization management may decrease N-leaching significantly and greatly decrease the risk of ground water being contaminated by NO3-N leaching in the Salt Lake Valley.

Comments

This work made publicly available electronically on November 21, 2011.

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