This study is based on the work of Professor Mariusz Fotyma, Institute of Soil Science and Plant Cultivation, Pulawy, Poland.
The study benefited from the contributions of C. Aholou-Pütz (IFA), K. Isherwood, J. Poulisse and T. van den Bergen (FAO).
The cover photographs were made by Arnoldo Mondadori Editore S.p.A. (potatoes), Arne Anderberg (rye) and C. Borgemeister (wheat). The source of these photographs is EcoPort (Portal to Ecology Management).
