to
The Graduate School
in Partial Fulfillment of the Requirements
for the degree of 

Master of Science

in
Hydrogeology
Department of Geosciences
State University of New York
at Stony Brook

December 2001

Abstract

Nitrate is a widespread contaminant of groundwater supplies at the local and national levels.  Leaching of nitrogen from turf systems is of concern for environmental and economic reasons.  Past studies have documented that nitrogenous fertilizer applied to a turfgrass system can pose a threat to groundwater quality.  Nitrate levels in potable groundwater must remain below 10 mg/L and, in suburban environments, levels can be elevated by lawn fertilizers as well as sewage septic systems.  Overfertilization can be an unnecessary expense not only for the homeowner but for golf courses, municipal parks and others involved with turf management.  The turfgrass system is complex and a complete study requires an examination of multiple variables. 

This study initiates, a tension lysimeter system, in two study plots to assess the leaching of nitrate from fertilizer through a turf system.  The observations from this installation will be continued as part of an ongoing study of the sites on Long Island.  The two sites, located at the State University of New York (SUNY) at Stony Brook and the Suffolk County Water Authority (SCWA) at Oakdale, differ in the nature of turfgrass cover and management.  The turfgrass at the SUNY site is newly planted sod and the SCWA turfgrass is greater than ten years in age.  The SUNY site is fertilized according to the suggestions from the sod company and the SCWA is fertilized and managed by an outside landscaping company.  The tension lysimeter system allows for the collection of soil water in a manner that minimizes soil disturbance.  Nitrate nitrogen concentrations, were on average below drinking water standards, but some of the samples were above the standard.  At these levels, the turfgrass system poses a threat to groundwater quality, depending on the extent of fertilization.

Table of Contents

                                               

                                                                 

I.                    Introduction                                                                            

II.                 Background 

  Nitrate and the Nitrogen Cycle on  Long Island 

  Fate of Turf Nitrogen                                                             

III.               Site Description

SUNY Stony Brook Site 

SCWA Site                                                                       

 IV.              Methods

Lysimeter Monitoring  System  

Lysimeter Design    
Lysimeter Installation
Lysimeter Operation  
Chemical Analysis                                                           

V.                 Results and Discussion 

Nitrate Levels

Lysimeter Operation                                                           

VI.              Future of Study                                                                     

 References                                                                                          

Appendix I – SUNY Irrigation and Precipitation Data 

Appendix II - Lysimeter Instruction Manual 

List of Figures and Tables

 

Figure 1 – SUNY Site Map

Figure 2 – Aerial Sketch of SUNY Site

Figure 3 – Profile of SUNY Site 

Figure 4 – SCWA Site

Figure 5 – Profile of SCWA Site

Figure 6 – PVC Lysimeter

Figure 7 – Acrylic Lysimeter 

Figure 8 – Head Assembly

Figure 9 – Lysimeter Installation Profile

Figure 10 – Sample Collection

Figure 11 – SUNY Nitrate Nitrogen Concentrations

Figure 12 – SCWA Nitrate Nitrogen Concentrations                                        

Figure 13 – Study of Total Inorganic Nitrogen Under a Well- Kept Household Lawn

Figure 14 – Comparison of Nitrate Nitrogen Concentrations to Depth at Both Sites

Table 1 – Comparison of Nitrate Concentrations at the SUNY and SCWA Sites