Nitrogen leaching and Tifway bermudagrass response to simultaneous nutrient and pre‐emergence herbicide applications

Abstract

Pre‐emergence (PRE) herbicides are commonly applied simultaneously with fertilizers to turfgrass; however, the influence of PRE herbicides on nitrogen (N) uptake and leaching from turfgrass remains unclear. The hypothesis of this study was that PRE herbicides applied simultaneously with N fertilizers increase N leaching from Tifway 419 bermudagrass [Cynodon dactylon (L.) Pers. × C. transvaalensis Burtt‐Davy, ‘Tifway’] above that from fallow soil. A nutrient leaching study was conducted from June 2017 through June 2019 in Fort Lauderdale, FL. Treatments consisted of indaziflam (25 g a.i. ha–1), prodiamine (540 g a.i. ha–1), and oxadiazon (4,480 g a.i. ha–1); a nontreated turfgrass control (turfgrass fertilized but not treated with PRE herbicides); and a fallow soil. Fertilizer (15–2–12) was applied every 60 d at 49 kg N ha–1, and PRE herbicides were applied every 120 d. Pre‐emergence herbicides resulted in a 3.6‐ and 5.5‐fold increases in NO3–N concentration compared with fallow soil during June 2017 and January 2018, respectively, whereas fallow soil resulted in increased NO3–N concentration during 10 mo and ranged from 3.8‐ to 15‐fold greater than that from turfgrass plots. Turfgrass plots resulted in reduced N leaching of ∼7% during 5 mo compared with fallow soil and did not result in increased N leaching during any month. Cumulative N leached from turfgrass plots ranged from 75 to 120 kg ha–1 and did not differ from fallow soil. Turfgrass growth rate and N uptake were not influenced by PRE herbicide. The results indicated that fertilizers applied with PRE herbicides does not result in increased N leaching or reduced N uptake.