| Splash erosion and soil and water loss was liable to occur in sandy soil. Enrichment characteristic of ammonia-nitrogen on different grain sizes micro-aggregate of sandy soil was investigated by batch experiments of equilibrium adsorption in order to estimate the loss flux of its adsorption state. Results indicated that the enrichment effect on ammonia-nitrogen was attributed greatly to micro-aggregate of sandy soil. Firstly, humus content of fine grain size aggregate was higher than that of coarse grain size aggregate. Secondly, organic matter of fine grain size aggregate was enriched by clay mineral, which was combined with dissoluble organic matter. The content of stably combined humus in clay or silt was higher relatively, and there was a micro-hole filling function in ammonium-nitrogen sorption on complex. Stably combined humus is an important adhesive material in the formation of organo-mineral complex. Micro-hole filling mechanism was the cause of enrichment of ammonia-nitrogen on different grain sizes micro-aggregate. Furthermore, there was a highly obvious positive correlation between enrichment ratio and total humus content（R2=0.909）, and so was it with stably combined humus content（R2=0.902）. Consequently, mass percentages of adsorption state ammonia-nitrogen carried by clay and silt from West Liao River sandy soil under rainfall condition were estimated in accordance with 3 641.49 mg·kg-1 and 2 617.52 mg·kg-1 respectively, and enrichment ratios of clay and silt were estimated in accordance with 1.65 and 1.18 respectively. |
