Hillslope runoff and erosion on duplex soils in grazing lands in semi-arid central Queensland. II. Simple models for suspended and bedload sediment

摘要: The use of simple models soil erosion which represent the main effects management in grazing lands northern Australia is limited by a lack measured parameter values. In particular, parameters are needed for (sediment concentration v. cover equations) used daily soil-water balance models. For this research, we specifically avoided equations that rainfall and runoff rates (e.g. peak flow), as current their ability to estimate these rates. resulting will therefore give poor estimates losses individual events, but should good long-term average influences. Runoff data were available 7 years on 12 hillslope plots with 10–80%, without grazing, tree canopy cover, variety soils according various classification systems. Soils grouped into those derived from sandstone (SS), mudstone (MS), eroded (MSe). These determine two parameters, i.e. (i) efficiency entrainment bare (ii) factor, bedload suspended sediment concentrations. Methods fit affected results; optimising obtain minimum sum squares errors gave better results than fitting an exponential equation concentration–cover data. linear slope factor was confirmed slopes 4–8%. Parameters model same SS, MS, MSe soils. SS MS soils, had greater (about double). relationships fitted factors different sediment. Thus, modelled proportion load changed ~0.3 0.9 at 80% mimicking lower published values cultivated indicating less reduction cover. A compilation unpublished sources cropping provided.