| 1 | An exploratory study on the use of enzyme activities as sediment tracers:biochemical fingerprints?显示文摘Little information exists on the potential of soil enzyme activities,which are sensitive to soil properties and management,for the characterization of sediment sources at the catchment scale.The objective of this study is to explore and evaluate enzyme activity as tracer for sediment fingerprinting in the Hiv catchment(55 km^2),Iran.Therefore,four enzymes were measured from 42 different sampling sites,covering three sediment source areas(rangeland/surface erosion,orchard/surface erosion,and streambank erosion),as well as from 12 sediment samples from reservoir check dams (sediment sinks).The results indicate that,based upon backward mode discriminant analysis,βglucosidase and dehydrogenase,allowed more than 95%of the samples to be correctly assigned to their source areas.These enzymes were selected as input data for a mixing-model to determine the relative contribution of the sampled sediment sources.The mean contributions from rangeland, orchard and streambank sources in the study area were estimated as 11.3%,15.1%and 73.7%, respectively.Using geochemical tracers,the mean contribution from rangeland,orchard and streambank sources was estimated as 14.1%,9.5%and 74.8%,respectively.Combined biochemical and geochemical tracers,similar values were obtained(18.7%,10.7%and 70.7%,respectively).Our results indicate that soil enzyme activity allows for a good characterization of sediment sources,and can provide a complementary tool to currently existing sediment fingerprinting approaches.However, the method should be also tested in other regions. | Kazem NOSRATI Gerard GOVERS Hassan AHMADI Forood SHARIFI Mohammad Ali AMOOZEGAR Roel MERCKX Matthias VANMAERCKE | 2011 | International Journal of Sediment Research2011，26，2： | 5 |
| 2 | A soil quality index for evaluation of degradation under land use and soil erosion categories in a small mountainous catchment, Iran显示文摘Soil erosion and land use type have long been viewed as being particularly important drivers of soil degradation.The objectives of this study,therefore,were to select a new soil quality index(SQI)which varies significantly with land use/soil erosion,and to evaluate the new SQI using expert opinion.In total,18 soil physical,chemical,and biochemical properties(indicators)were measured on 56 soil samples collected from four land use/soil erosion categories(rangeland/surface erosion,rangeland/subsurface erosion,cultivated land/surface erosion and dry-farming land/surface erosion).Principal component and classification analysis(PCCA)identified five PCs that explained 77.7%of the variation in soil properties with the biochemical PC varying significantly with land use/soil erosion.General discriminant analysis(GDA)selected urease and clay as the most sensitive properties distinguishing the land use/soil erosion categories.The GDA canonical scores for the new SQI were significantly correlated with expert opinion soil surface summed scores(for soil movement,surface litter,pedestalling,rills and flow pattern)derived using the U.S.Department of the Interior Bureau of Land Management(BLM)method.A forward stepwise general regression model revealed that the new SQI values were explained by soil movement,surface litter,and the summed values of the soil surface factors.Overall,this study confirmed that soil quality in the study area in Iran is controlled by land use and corresponding soil erosion. | Kazem NOSRATI Adrian LCOLLINS | 2019 | Journal of Mountain Science2019，16，11： | 2 |
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