The Fate of Nitrogenous Fertilizer Applied to
Differing Turfgrass Systems

A Research Report

by

Peter F. Schuchman

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