Effects of mowing interval on turfgrass clipping tissue characteristics and soil nitrogen dynamics.

Understanding the role of clipping biomass in nutrient budgets of turfgrass systems is critical to improving N use efficiency (NUE). The objective of this study was to evaluate the effect of mowing frequency on clipping tissue characteristics, N mineralization (NMin, %), and NH3 volatilization (AV, %) from decomposing 'TifTuf' bermudagrass [Cynodon dactylon (L.) Pers. × Cynodon transvaalensis Burtt Davy] clippings applied to the soil surface. Turfgrass clippings were collected from two research facilities in Athens, GA, at 3‐, 7‐, 10‐, and 14‐d mowing intervals (MIs). A subsample of clippings from each plot was ground and analyzed using near‐infrared spectroscopy to determine tissue characteristics. Soil from each location was packed into polyvinyl chloride cylinders, treated with grass clippings on the surface or left unamended, and incubated for 90 d. Cumulative evolved NH3 was trapped, and inorganic N was extracted from each cylinder and analyzed colorimetrically after 90 d. Rates of NMin varied significantly across treatments and locations, making it difficult to generate informed recommendations for reducing N fertilization based on MI. Although dry yield (g m–2) and tissue characteristics (carbohydrates, cellulose, and lignin) were found to be significant parameters in predicting NMin, no clear relationship was established between MI and tissue characteristics in this study. More frequent mowing (3‐d MI) appeared to support more vigorous turfgrass growth through greater net clipping yield and may also decrease AV as a function of smaller clipping yield for unique mowing events. Mowing more than one time per week may be more N‐use efficient and promote healthier turfgrass systems overall. Core Ideas: Mowing interval does not appear to affect turfgrass clipping tissue composition.More frequent mowing may bolster turfgrass health and reduce NH3 volatilization losses.Nitrogen mineralization can be highly variable, even in a controlled environment. [ABSTRACT FROM AUTHOR]