Using and managing soils

CONSERVATION IN THE UNITED STATES GUSTAFSON, A.F. SOILS AND SOIL MANAGEMENT GUSTAFSON, A.F. Handbook of fertilizers Gustafson, A.F. Conservation of the soil GUSTAFSON, A.F. Soils and soil fertility THOMPSON, Louis M. Desert Institute bulletin: Volume XXI, No.2 Desert Institute bulletin: Volume XXI, No.1 Elements of soil conseration BENNETT, Hugh Hammond