Mgr inż. Sylwia Gołda, dr hab. inż. Jolanta Korzeniowska, prof. nadzw., Department of Weed Science and Soil Tillage Systems in Wroclaw, Institute of Soil Science and Plant Cultivation - State Research Institute in Pulawy, Orzechowa 61 St., 50-540 Wroclaw, Poland; Phone: 071-3638707