Annual Nitrogen Requirement of Bahiagrass Lawns Maintained in Subtropical Climates
2017
(John L.),
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.
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