Agroecological efficiency of periodic use of neutralized phosphogypsum in rice crops Maria Vizirskaya, Ashad Sheydgen, Natalia Akanova, Vasilii Zhdanov, Maria Tihonova and Alexey Buzylev E3S Web Conf., 175 (2020) 07004 Published online: 29 June 2020 DOI: 10.1051/e3sconf/202017507004