Abstract: Some macromolecule materials, widely used for soil surface conditioning in agricultural field at present, were selected to determine their effects of simulated surface application on soil aggregate-related physical properties, including on surface film-formation, soil erosion-resistance, changes in dry/wet particle-size distribution, soil aggregation and water-stability, as well as hydraulic conductivity, and to make comparison and evaluation of soil stability associated with the tested materials. The results suggested that the SQ (stability quotient), A% (percentage of dry-sieved aggregates >2 mm) and WMWD (wet-sieved mean-weight diameters) be used as main index to measure soil dry/wet aggregate stability or to evaluate soil stability of macromolecule materials. In comparison of the tested materials, the highest values in SQ, A% and WMWD associated with M-PAM (polyacrylamide) surface treatment showed that MPAM had the strongest effects on film-formation, erosion-resistance, and aggregate water-stability and can be recommended as practices combined with water-saving irrigation and soil conservation tillage in dryland soil. With EBT (emulsified bituminous material) treatment, the least A%, but the higher SQ and WMWD indicated that EBT had stronger aggregate water-stability and can be used on slope and sandy land for protecting soil against water erosion. With CLP (crosslinked polyacrylamide) treatment, the higher A%, but the lower SQ and WMWD suggested that CLP had the weaker wet aggregate water-stability and is suitable for water and fertilizer conservation in seasonal drought soils, and especially is applicable for water-saving cultivation management of cash crops. This study has provided informations for the development of new-type macromolecule materials in agricultural land application.

Key words: Macromolecule materials, Soil structure, Soil stability