Abstract: This paper applies system theory and engineering techniques to establish a forest-farmland-grassland complex ecosystem by making up different temporal and spatial combination ofperennial woody plant,grass and crops according to the unity of ecology and economics.Itaims to find new ways to fully use land,space,light,temperature,water and fertilizers andraise productivity of the sandy land.Principles and policies for agroecological constructionin sandy land of semi-humid temperate zones are put forward.

Key words: Phaiozem, Pb, Bioavailability, Acetochlor, Contaminated soil