Chapter 4 Nitrogen Fate in a Mature Kentucky Bluegrass Turf

摘要

Research on nitrate-nitrogen (NO_3-N) leaching in immature turfgrass systems indicates that, in most cases, leaching poses little risk to the environment. This may not be true for mature stands of turfgrass. In this study, the fate of nitrogen (N) was examined over two years for a 10-year old Kentucky bluegrass (Poa pratensis L.) turf in monolith lysimeters. Two nitrogen rates were analyzed: 245 kg N ha~(-1) (49 kg N ha~(-1) application~(-1)) and 98 kg N ha~(-1) (24.5 kg N ha~(-1) application~(-1)). NO_3-N concentrations in leachate for the low N rate were typically below 5 mg L~(-1). For the high N rate, NO_3-N concentrations in leachate were often greater than 20 mg L~(-1), now < than 10 mg L~(-1). Results emphasize the importance of long-term research to investigate nutrient fate in turfgrass and lend support support to the theory that older turf sites should be fertilized at a reduced N rate to minimize the potential for NO_3-N leaching.