CREA-Council for Agricultural Research and Economics;
Research Center for Agriculture and Environment;
Via della Navicella 2;
Rome 00184 (Italy);
Japan International Research Center for Agricultural Sciences (JIRCAS);
Tsukuba 305-8686 (Japan);
ammonium-N; crotonylidene; diurea; isobutylidene; diurea; nitrate-N; non-linear; regression; urea-formaldehyde;