Clippings return decreases mineral nitrogen requirements for bermudagrass (Cynodon spp.) lawns in Mediterranean Europe

The use of bermudagrass [Cynodon dactylon (L.) Pers.] and hybrid bermudagrass (C. dactylon x C. transvaalensis Burtt Davy) in lawns is rapidly increasing in Mediterranean Europe; however, the identification of optimal N fertilization practices is needed to shorten the long dormancy periods some cultivars undergo in these environments. A 2-yr study was conducted at the agricultural experimental farm of Padova University from May 2016 until June 2018 to compare the effects of three N fertilization rates (160 kg N ha−1 without clippings returned, 80 kg N ha−1 with clippings returned, and 80 kg N ha−1 without clippings returned applied with a controlled-release fertilizer) on two bermudagrass cultivars (‘La Paloma’, ‘Yukon’) and two hybrid bermudagrass cultivars (‘Patriot’, ‘Tifway’) by measuring summer and fall quality, spring green-up, and root morphology. Bermudagrasses fertilized at 160 kg N ha−1 without clippings returned slightly increased turfgrass quality in the summer, but higher turf quality was recorded in plots fertilized at 80 kg N ha−1 with clippings returned after weekly mowing events in the fall. The same N rates had a positive effect on spring green-up for ‘La Paloma’ and ‘Tifway’; however, no benefits of increased N rates were detected on root morphology. Results suggest that returning clippings can be a powerful tool for reducing mineral N applications and increase growing season length in northern Italy.