The Fate of Nitrogen Applied to a Mature Kentucky Bluegrass Turf

Abstract

Research on nitrate-nitrogen (NO 3 -N) leaching in turfgrass indicates that, in most cases, leaching poses little risk to the environment. Most of the research was conducted on sites that were recently established, and the potential for greater NO 3 -N leaching from mature turf sites is unknown. The fate of nitrogen (N) was examined for a 10-yr-old Kentucky bluegrass (Poa pratensis L.) turf using intact monolith lysimeters and microplots. From October 2000 through July 2002, half of the lysimeters and microplots were treated annually with urea at a high rate of 245 kg N ha 21 (49 kg N ha 21 application 21 ). The remaining lysimeters and microplots were treated annually with urea at a low rate of 98 kg N ha 21 (24.5 kg N ha 21 application 21 ). The Oct. 2000 urea application was made with 15 N double-labeled urea to facilitate fertilizer identification among clippings, verdure, thatch, soil, roots, and leachate. The average total recovery of applied labeled fertilizer nitrogen (LFN) for the low and high N rates was 78 and 74%, respectively. NO 3 -N concentrations in leachate for the low N rate were typically below 5 mg L 21 . For the high N rate, NO 3 -N concentrations in leachate were often greater than 20 mg L 21 . Over approximately 2 yr, 1 and 11% of LFN was recovered in leachate for the low and high N rates, respectively. This research indicates that single dose, high rate, water soluble N applications (49 kg N ha 21 application 21 ) to mature turfgrass stands should be avoided to minimize the potential for NO 3 -N leaching.

Nitrogen budgets of urban lawns under three different management regimes in southern California

“…At the annual scale, clipping biomass N for each of the three lawns was estimated as the sum of biomass N from all mowing events. We did not measure the aboveground biomass that remained after mowing (verdure), since it was always left at similar height and not likely to vary very much in N stocks (Engelsjord et al 2004;Frank et al 2006).…”

“…Therefore, it is important to study the N biogeochemistry of fertilized urban lawns within the context of global change. 15 N-tracer studies have shown that mineral soil and plant biomass are usually the primary sinks for fertilizer N in lawns (Engelsjord et al 2004;Frank et al 2006;Horgan et al 2002a, b;Raciti et al 2008). Raciti et al (2008) and Frank et al (2006) similarly reported a peak recovery of 15 N-labeled fertilizer in plant biomass within a short period (days), while soils dominated the long-term 15 N recovery (C1 year) in urban lawns.…”

“…15 N-tracer studies have shown that mineral soil and plant biomass are usually the primary sinks for fertilizer N in lawns (Engelsjord et al 2004;Frank et al 2006;Horgan et al 2002a, b;Raciti et al 2008). Raciti et al (2008) and Frank et al (2006) similarly reported a peak recovery of 15 N-labeled fertilizer in plant biomass within a short period (days), while soils dominated the long-term 15 N recovery (C1 year) in urban lawns. However, a large portion of 15 N could remain in clipping biomass, if such clippings were removed from the lawns instead of being left on site (Engelsjord et al 2004;Horgan et al 2002a, b).…”

“…Fertilizer N that exceeds plant needs and soil capacity may leave lawns in various ways, while the potential of high N losses in response to overfertilization may increase with lawn age (Frank et al 2006). Excessive N inputs to lawns may enter groundwater as ammonium (NH 4 ? )…”

Introduction to Ecological Landscaping: A Holistic Description and Framework to Guide the Study and Management of Urban Landscape Parcels

“…A common output that readily crosses parcel boundaries is the noise generated by landscaping tools such as lawn mowers and leaf blowers; while certainly noticeable by humans, the collective noise created in urbanized environments has also been found to affect the songs of urban birds (Slabbekoorn and Margriet 2003;Wood and Yezerinac 2006). Although other research has been conducted on the physical-ecological outputs from urbanized landscapes (e.g., gases: Kaye et al 2004;Byrne et al 2008; water and nutrients: Easton and Petrovic 2004;Frank et al 2006), this aspect of the ecological landscaping framework remains a relatively unexplored area of study in need of future study.…”