Use of winter cover crops improves maize productivity under reduced nitrogen fertilization: a long-term study - Piva, Jonatas Thiago; Bratti, Felipe; Locatelli, Jorge Luiz; Ribeiro, Ricardo Henrique; Besen, Marcos Renan; Brancaleoni, Eduardo; Schmitt, Djalma Eugenio (Bragantia, 2021)