An applicability assessment and sensitivity analysis of land use impact models: application of the LANCA model in site-specific conditions

Purpose In this work, we study a land use impact model with the aim of obtaining spatially differentiated as opposed to default average characterisation factors. In particular, we study the application of LANCA®, a multi-indicator model with available country average characterisation factors expressing the alteration of the soil quality level of the current land use of one kind with respect to a reference situation. Method To this purpose, we use the LANCA® method documentation at a higher spatial resolution and apply all the required elemental steps. From a user perspective, we score the transparency of the method down to the basic methodological references and single out the source of errors that the user may incur when: (i) collecting the input data, (ii) selecting the appropriate soil/land classes and (iii) applying the individual calculation steps. For a greater insight, we couple the source of errors with a sensitivity analysis. Results In the comparison between a site-specific test area and the related country default values, we obtained relevant discrepancies regarding the erosion resistance and the physicochemical filtration of the soil. For example, we find that the erosion resistance potential is −1.06 * 10−3 kg m2 a−1 locally while the country default value is 13.1. We explain differences through the sensitivity analysis and having analysed in depth the underpinned soil erosion equation and the critical steps for its calibration. Together with systematic errors, we find that the method generally implies 9 scarcely guided steps out of 42, and one-third of the basic methodologies are not fully explained or accessible. These factors make the results related to Biotic Production, Mechanical Filtration, Physicochemical Filtration and Groundwater Regeneration user dependent and — in this sense — difficult to replicate. Conclusions From the analysis, we distil 7 main directions for improvement addressed to LANCA® and soil models especially in sight of a broader application of a regionalised life cycle impact assessment.

Comparison of the Spatial Wind Erosion Patterns of Erosion Risk Mapping and Quantitative Modeling in Eastern Austria

Various large-scale risk maps show that the eastern part of Austria, in particular the Pannonian Basin, is one of the regions in Europe most vulnerable to wind erosion. However, comprehensive assessments of the severity and the extent of wind erosion risk are still lacking for this region. This study aimed to prove the results of large-scale maps by developing high-resolution maps of wind erosion risk for the target area. For this, we applied a qualitative soil erosion assessment (DIN 19706) with lower data requirements and a more data-demanding revised wind erosion equation (RWEQ) within a GIS application to evaluate the process of assessing wind erosion risk. Both models defined similar risk areas, although the assignment of severity classes differed. Most agricultural fields in the study area were classified as not at risk to wind erosion (DIN 19706), whereas the mean annual soil loss rate modeled by RWEQ was 3.7 t ha−1 yr−1. August was the month with the highest modeled soil loss (average of 0.49 t ha−1 month−1), due to a low percentage of vegetation cover and a relatively high weather factor combining wind speed and soil moisture effects. Based on the results, DIN 19706 is suitable for a general classification of wind erosion-prone areas, while RWEQ can derive additional information such as seasonal distribution and soil loss rates besides the spatial extents of wind erosion.

Changes in wind erosion climatic erosivity in northern China from 1981-2016: a comparison of two climate/weather factors of wind erosion models

Wind erosion is largely determined by wind erosion climatic erosivity. In this study, we examined changes in wind erosion climatic erosivity during 4 seasons across northern China from 1981-2016 using 2 models: the wind erosion climatic erosivity of the Wind Erosion Equation (WEQ) model and the weather factor from the Revised Wind Erosion Equation (RWEQ) model. Results showed that wind erosion climatic erosivity derived from the 2 models was highest in spring and lowest in winter with high values over the Kumtag Desert, the Qaidam Basin, the boundary between Mongolia and China, and the Hulunbuir Sandy Land. In spring and summer, wind erosion climatic erosivity showed decreasing trends in whole of northern China from 1981-2016, whereas there was an increasing trend in wind erosion climatic erosivity over the Gobi Desert from 1992-2011. For the weather factor of the RWEQ model, the difference between northern Northwest China and the Gobi Desert and eastern-northern China was much larger than that of the wind erosion climatic erosivity of the WEQ model. In addition, in contrast to a decreasing trend in the weather factor of the RWEQ model over southern Northwest China during spring and summer from 1981-2016, the wind erosion climatic erosivity of the WEQ model showed a decreasing trend for 1981-1992 and an increasing trend for 1992-2011 over southern Northwest China. According to a comparison between dust emission and wind erosion climatic erosivity, the 2 models have the ability to project changes in future wind erosion in northern China.

Comparison of Two Different Calculation Methods of Fractional Vegetation Cover

Fractional Vegetation Cover (FVC) is an important parameter for soil erosion equation. The Fractional Vegetation Cover of typical soil erosion county in red soil region of South China was calculated by parameter revision method (PRM) and fusion method (FM).The results of the two methods were compared from two parts of FVC level and 24 half-months FVC. The results show that the FVC level calculated by PRM was concentrated in high level, and that calculated by FM is mainly in medium-high level and high level. The time variation of FVC in 24 half-months calculated by the two methods was the same, but the majority of FVC value calculated by PRM was higher than that calculated by FM. It is better to choose FM method to calculate FVC in estimating soil erosion.

Risk Assessment of Drifting Sand in Agricultural Lands in Basrah Province with the aid of ‘3S’ Techniques

There is a growing need to systematically assessment of drifting sand risk using Geo-information and related technologies for speed and accuracy. The drifting sand map in the southern part of Iraq was established with objective of providing the risk areas of soil loss and the methodology for spatial modeling with Wind Erosion Equation (WEQ) and Geo-information techniques. This analysis was carried out using ‘3S’ technologies [Remote Sensing (RS), Geographic Information System (GIS) and Global Position System (GPS)], with the layers extracted and manipulated from available topographic, climatic and soil maps, as well as satellite image (Thematic Mapping (TM) in 2003 and Enhanced Thematic Mapping (ETM) in 2016) and field survey data analyses. Each of the WEQ factors was digitally encoded in a GIS database to establish each factor’s layers. Simultaneously, the overlay operation with the WEQ model on the factor’s layers was digitally performed to produce the sandy degradation class. The study indicated that the severe erosion class covering an area of about 61.9% of the total area is very high with the degraded vegetation and is located in the southwest part of Iraq. Iraq faces serious environmental degradation problems that must be addressed immediately; failure to do so will greatly compound the cost and complexity of later remedial efforts, with environmental degradation beginning even now to pose a major threat to human well-being, especially among the poor.

Determination of erosion equation factors of AISI1020 by experimental data

Erosive wear is material removal due to the impingement of granular flow. In the present work, the effects of influencing parameters including flow velocity, incidence angle and grain size on erosive behavior of AISI1020 subjected to a flow of SiC particles has been investigated by employing an erosion wear test machine. The experiments have been performed at the different values of impact angle, flow velocity and particle size. Two tests have been performed for every set of conditions and the average of them has been presented. Results showed that the erosive wear maximizes at the impact angles of 30° and 45°. The flow of small particles resulted in more wear contrast to the large particles. Results also indicated that the influence of flow velocity was higher than the influence of impact angle and particle size. It means that minimizing the flow velocity results in more efficient results to reduce erosion. Moreover, the experimental data were used to determine appropriate coefficients for using in an erosion equation given by literature. New factors gave erosion evaluations which had appropriate accordance with the experimental data.