Influence of amendments on soil structure and soil loss under simulated rainfall China’s loess plateau
Macromolecule polymers are significant types of chemical amendments because of their special structure, useful functions and low cost. Macromolecule polymers as soil amendment provide new territory for studying China’s agricultural practices and for soil and water conservation, because polymers have the ability to improve soil structure, increase rainfall penetration and control slope runoff. Through indoor laboratory experiments and outdoor artificial rainfall simulations, this study applied different consistencies of three amendments; polypropylene acid (PPA), polythene alcoholic (PTA) and urea-formaldehyde poly-condensate (UR) to China’s Loess and determined their effects on soil physical properties and on runoff-sediment yield. The results indicate that as a result of applying the amendments, (1) the water-stable soil aggregates content increases by 17.3%, the soil permeability increases by 41.8%, the soil density decreases by 11.2% and the soil water content increases by 28.0% compared to the control; (2) three amendment applied on sloping land can delay runoff and decrease runoff velocity; decrease erosive forces of raindrop impact and flowing water, reduce surface crusting and improve water infiltration, delay runoff engenderation and decrease runnoff velocity and soil erosion yield. Finally, this study also ascertained optimal application quantities and the most effective sort in three amendments, which PPA is most effective at lowering surface runoff, reducing soil loss and increasing soil penetration. These three amendments have broad potential for soil and water conservation; however, the duration of their effect and the optimal application quantities need to be researched further.
Key words: Amendment, Runoff-Sediment Yield, Soil Physical Properties, Soil erosion