Active and passive microwave measurements for the characterization of soils and crops Giovanni Macelloni, Simonetta Paloscia, Paolo Pampaloni, Roberto Ruisi, Monique Dechambre, René Valentin, André Chanzy and Jean-Pierre Wigneron Agronomie, 22 6 (2002) 581-586 DOI: 10.1051/agro:2002031