Annual Nitrogen Requirement of Bahiagrass Lawns Maintained in Subtropical Climates

Abstract

Current best management practices (BMPs) regarding the application of nitrogen (N) to bahiagrass (Paspalum notatum Flügge) in southern Florida are 98 to 196 kg ha−1 yr−1. This range has not been tested to determine if the range adequately produces quality bahiagrass without adversely contributing to nonpoint source additions of N to ground water. The objectives of this research were to determine the N necessary to support acceptable bahiagrass quality by measuring associated color, growth, and nitrate‐N (NO3–N) leaching. Research was conducted from October 2006 to October 2008 in Fort Lauderdale, FL. Nitrogen was applied in 60‐d cycles at rates of 49, 98, 196, or 294 kg ha−1 yr−1 under two irrigation regimes (2.5 mm d−1 and 13 mm three times weekly). Bahiagrass quality and color was acceptable under each N rate during each cycle and regression indicated application of N to bahiagrass was not necessary to produce acceptable turfgrass. Nitrate‐N leaching was unaffected by N rates during each cycle except during Cycle 3 of 2008 when the 196 and 294 kg ha−1 yr−1 led to 93 and 94% greater leaching, respectively, than the 49 kg ha−1 yr−1. The high‐irrigation regime increased NO3–N leaching by as much as eightfold but was not consistent among cycles. If current N recommendations were revised downward (∼49 kg ha−1 yr−1), bahiagrass quality would remain acceptable and the risk of NO3–N leaching would be reduced.

Nutrient Use and Management Practices on United States Golf Courses

“…A reduction of applied N results in less N available for plant uptake, but, depending on many factors, including turfgrass type, soil, and environmental conditions, it may not necessarily result in a reduction of turfgrass quality (Tang 2018). Recent research has shown that N rates that were previously recommended may exceed the minimum necessary to result in acceptable turfgrass (McGroary et al 2017). Therefore, the reduced N rates measured during the current study are consistent with current evidence and may result in reduced environmental risk (Shaddox et al 2016b) and maintenance costs without measurable loss of turfgrass quality.…”

The Fate of Nitrogen Applied to Florida Turfgrass

“…UF/IFAS turfgrass nutrient recommendations take into account the turfgrass need for N and the potential impact on the environment. UF/IFAS nutrient recommendations are often 50-75% less than the amount of N necessary to increase N leaching losses above the natural environment (McGroary et al 2017;Trenholm et al 2012). Thus, current rates are considered conservative, and exceeding these rates is unnecessary because any further increase in turfgrass growth or quality is minimal and could come at a cost to the environment.…”