Cesium-137-measured erosion rates for soils of five parent-material groups in southwestern Saskatchewan

1995 ◽  
Vol 75 (2) ◽  
pp. 205-210 ◽  
Author(s):  
D. J. Pennock ◽  
E. de Jong ◽  
D. S. Lemmen

Despite the wide-spread perception that the soils of southwestern Saskatchewan are particularly erosion prone, few observations have been made on soil loss in this area. We used 137Cs redistribution to examine rates of soil loss associated with five parent-material groups in this area. Five sites were sampled in each parent-material group: one uncultivated site and four cultivated sites. Ten samples were taken at each site from landscape positions that have been shown in previous studies to have the highest rates of soil loss. The highest rates (median soil loss of −30 t ha−1 yr−1) were associated with glacial till landscapes; medium (−21 t ha−1 yr−1) but highly variable rates of loss, with coarse sandy glaciofluvial–lacustrine landscapes; and lower and consistent losses of around −12 t ha−1 yr−1, with silty glaciolacustrine and aeolian landscapes and with fine sandy glaciofluvial–lacustrine landscapes. The observed rates of loss can be used to calibrate models of geomorphic instability for this area. Key words: Soil erosion, soil quality, landscape-scale analysis, soil organic matter

2021 ◽  
Author(s):  
Anna Schneider ◽  
Alexander Bonhage ◽  
Florian Hirsch ◽  
Alexandra Raab ◽  
Thomas Raab

<p>Human land use and occupation often lead to a high heterogeneity of soil stratigraphy and properties in landscapes within small, clearly delimited areas. Legacy effects of past land use also are also abundant in recent forest areas. Although such land use legacies can occur on considerable fractions of the soil surface, they are hardly considered in soil mapping and inventories. The heterogenous spatial distribution of land use legacy soils challenges the quantification of their impacts on the landscape scale. Relict charcoal hearths (RCH) are a widespread example for the long-lasting effect of historical land use on soil landscapes in forests of many European countries and also northeastern USA. Soils on RCH clearly differ from surrounding forest soils in their stratigraphy and properties, and are most prominently characterized by a technogenic substrate layer with high contents of charcoal. The properties of RCH soils have recently been studied for several regions, but their relevance on the landscape scale has hardly been quantified.</p><p>We analyse and discuss the distribution and ecological relevance of land use legacy soils across scales for RCH in the state of Brandenburg, Germany, with a focus on soil organic matter (SOM) stocks. Our analysis is based on a large-scale mapping of RCH from digital elevation models (DEM), combined with modelled SOM stocks in RCH soils. The distribution of RCH soils in the study region shows heterogeneity at different scales. The large-scale variation is related to the concentration of charcoal production to specific forest areas and the small-scale accumulation pattern is related to the irregular distribution of single RCH within the charcoal production fields. Considerable fractions of the surface area are covered by RCH soils in the major charcoal production areas within the study region. The results also show that RCH can significantly contribute to the soil organic matter stocks of forests, even for areas where they cover only a small fraction of the soil surface. The study highlights that considering land use legacy effects can be relevant for the results of soil mapping and inventories; and that prospecting and mapping land use legacies from DEM can contribute to improving such approaches.</p>


Author(s):  
Vito Ferro ◽  
Vincenzo Bagarello

Field plots are often used to obtain experimental data (soil loss values corresponding to different climate, soil, topographic, crop, and management conditions) for predicting and evaluating soil erosion and sediment yield. Plots are used to study physical phenomena affecting soil detachment and transport, and their sizes are determined according to the experimental objectives and the type of data to be obtained. Studies on interrill erosion due to rainfall impact and overland flow need small plot width (2–3 m) and length (< 10 m), while studies on rill erosion require plot lengths greater than 6–13 m. Sites must be selected to represent the range of uniform slopes prevailing in the farming area under consideration. Plots equipped to study interrill and rill erosion, like those used for developing the Universal Soil Loss Equation (USLE), measure erosion from the top of a slope where runoff begins; they must be wide enough to minimize the edge or border effects and long enough to develop downslope rills. Experimental stations generally include bounded runoff plots of known rea, slope steepness, slope length, and soil type, from which both runoff and soil loss can be monitored. Once the boundaries defining the plot area are fixed, a collecting equipment must be used to catch the plot runoff. A conveyance system (H-flume or pipe) carries total runoff to a unit sampling the sediment and a storage system, such as a sequence of tanks, in which sediments are accumulated. Simple methods have been developed for estimating the mean sediment concentration of all runoff stored in a tank by using the vertical concentration profile measured on a side of the tank. When a large number of plots are equipped, the sampling of suspension and consequent oven-drying in the laboratory are highly time-consuming. For this purpose, a sampler that can extract a column of suspension, extending from the free surface to the bottom of the tank, can be used. For large plots, or where runoff volumes are high, a divisor that splits the flow into equal parts and passes one part in a storage tank as a sample can be used. Examples of these devices include the Geib multislot divisor and the Coshocton wheel. Specific equipment and procedures must be employed to detect the soil removed by rill and gully erosion. Because most of the soil organic matter is found close to the soil surface, erosion significantly decreases soil organic matter content. Several studies have demonstrated that the soil removed by erosion is 1.3–5 times richer in organic matter than the remaining soil. Soil organic matter facilitates the formation of soil aggregates, increases soil porosity, and improves soil structure, facilitating water infiltration. The removal of organic matter content can influence soil infiltration, soil structure, and soil erodibility.


Radiocarbon ◽  
2009 ◽  
Vol 51 (2) ◽  
pp. 537-552 ◽  
Author(s):  
Filippo Favilli ◽  
Markus Egli ◽  
Dagmar Brandova ◽  
Susan Ivy-Ochs ◽  
Peter W Kubik ◽  
...  

Glacier fluctuations and paleoclimatic oscillations during the Late Quaternary in Val di Rabbi (Trentino, northern Italy) were reconstructed using a combination of absolute dating techniques (14C and 10Be) and soil chemical characterization. Extraction and dating of the stable fraction of soil organic matter (SOM) gave valuable information about the minimum age of soil formation and contributed to the deciphering of geomorphic surface dynamics. The comparison of 10Be surface exposure dating (SED) of rock surfaces with the 14C ages of resilient (resistant to H2O2 oxidation) soil organic matter gave a fairly good agreement, but with some questionable aspects. It is concluded that, applied with adequate carefulness, dating of SOM with 14C might be a useful tool in reconstructing landscape history in high Alpine areas with siliceous parent material. The combination of 14C dating of SOM with SED with cosmogenic 10Be (on moraines and erratic boulders) indicated that deglaciation processes in Val di Rabbi were already ongoing by around 14,000 cal BP at an altitude of 2300 m asl and that glacier oscillations might have affected the higher part of the region until about 9000 cal BP. 10Be and 14C ages correlate well with the altitude of the sampling sites and with the established Lateglacial chronology.


Soil Research ◽  
2018 ◽  
Vol 56 (4) ◽  
pp. 396 ◽  
Author(s):  
Thilo Rennert

The presence of geogenic CO2 has been recently identified as a soil-forming factor in soil on mofette sites. Topsoil samples (with a maximum CO2 concentration of 52% at 10 cm depth) were studied along a transect on a mofette site in the NW Czech Republic to further understand the processes within soil and the soil properties induced by CO2 in the soil atmosphere. Geogenic CO2 negatively affected the cation exchange capacity, the ratio of exchangeable Ca and Mg, and the total contents of Al, Mg and Mn. No effect was detected on a chemical index of weathering and the mineralogical composition of the clay fractions, which might be explained by the acidic parent material and the progress of soil development. Diffuse reflectance infrared spectroscopy indicated that the composition of particulate soil organic matter was partially affected by CO2 concentrations: the higher the CO2 concentrations, the smaller the extent of oxidative transformation and the smaller the abundance of carboxyl groups. In the clay fractions, stabilisation of transformed soil organic matter (SOM) was promoted by exchangeable Al. This study quantifies, for the first time, the correlation between geogenic CO2 and several inorganic soil properties and the composition of SOM in physical fractions.


2021 ◽  
Author(s):  
Malte Ortner ◽  
Michael Seidel ◽  
Sebastian Semella ◽  
Thomas Udelhoven ◽  
Michael Vohland ◽  
...  

Abstract. Soil organic matter (SOM) is an indispensable component of terrestrial ecosystems. Soil organic carbon (SOC) dynamics are influenced by a number of well-known abiotic factors such as clay content, soil pH or pedogenic oxides. These parameters interact with each other and vary in their influence on SOC depending on local conditions. To investigate the latter, the dependence of SOC accumulation on parameters and parameter combinations was statistically assessed that vary on a local scale depending on parent material, soil texture class and land use. To this end, topsoils were sampled from arable and grassland sites in southwestern Germany at four regions with different soil parent material. Principal component analysis (PCA) revealed a distinct clustering of data according to parent material and soil texture that varied largely between the local sampling regions, while land use explained PCA results only to a small extent. The obtained global and the different local clusters of the dataset were further analyzed for the relationships between SOC and mineral phase parameters in order to assess specific parameter combinations explaining SOC and its labile fractions. Analyses were focused on soil parameters that are known as possible predictors for the occurrence and stabilization of SOC (e.g. fine silt plus clay and pedogenic oxides). Regarding the global dataset, we found significant correlations between SOC and its labile fractions hot water-extractable C (HWEC) and microbial biomass C (MBC), respectively and the predictors, yet correlation coefficients were partially low. Mixed effect models were used to identify specific parameter combinations that significantly explain SOC and its labile fractions of the different clusters. Comparing measured and mixed effect models-predicted SOC values revealed acceptable to very good regression coefficients (R² = 0.41–0.91). Thereby, the predictors and predictor combinations clearly differed between models obtained for the whole data set and the different cluster groups. At a local scale site specific combinations of parameters explained the variability of organic matter notably better, while the application of global models to local clusters resulted in less sufficient performance. Independent from that, the overall explained variance generally decreased in the order SOC > HWEC > MBC, showing that labile fractions depend less on soil properties than on organic matter input and turnover in soil.


2021 ◽  
Vol 13 (4) ◽  
pp. 2244
Author(s):  
Alelgn Ewunetu ◽  
Belay Simane ◽  
Ermias Teferi ◽  
Benjamin F. Zaitchik

Mapping and quantifying land degradation status is important for identifying vulnerable areas and to design sustainable landscape management. This study maps and quantifies land degradation status in the north Gojjam sub-basin of the Upper Blue Nile River (Abbay) using GIS and remote sensing integrated with multicriteria analysis (MCA). This is accomplished using a combination of biological, physical, and chemical land degradation indicators to generate a comprehensive land degradation assessment. All indicators were standardized and weighted using analytical hierarchy and pairwise comparison techniques. About 45.3% of the sub-basin was found to experience high to very high soil loss risk, with an average soil loss of 46 t ha−1yr−1. More than half of the sub-basin was found to experience moderate to high level of biological degradation (low vegetation status and low soil organic matter level). In total, 80.2% of the area is characterized as having a moderate level of physical land degradation. Similarly, the status of chemical degradation for about 55.8% and 39% of the sub-basin was grouped as low and moderate, respectively. The combined spatial MCA of biological, chemical, and physical land degradation indicators showed that about 1.14%, 32%, 35.4%, and 30.5% of the sub-basin exhibited very low, low, moderate, and high degradation level, respectively. This study has concluded that soil erosion and high level of biological degradation are the most important indicators of land degradation in the north Gojjam sub-basin. Hence, the study suggests the need for integrated land management practices to reduce land degradation, enhance the soil organic matter content, and increase the vegetation cover in the sub-basin.


2004 ◽  
pp. 145-160 ◽  
Author(s):  
Jean Andre ◽  
Cécile Villenave ◽  
Fabienne Charpentier ◽  
Nicolas Bernier ◽  
Patrick Lavelle ◽  
...  

1999 ◽  
Vol 79 (4) ◽  
pp. 593-601 ◽  
Author(s):  
D. J. Pennock ◽  
B. L. McCann ◽  
E. de Jong ◽  
D. S. Lemmen

Although approximately 1.3 million ha of mixed Solonetzic – Chernozemic landscapes are cultivated in Saskatchewan, little information is available on the effects that agriculture has had on the quality of these soils. At our research site in southwestern Saskatchewan a clear landscape-scale pattern of soil distribution occurred. Regosolic and thin Chernozemic soils were associated with the long, gentle (2–5%) slopes and Solonetzic-influenced soils were associated with higher catchment area footslope and depressional positions. High rates of soil loss occurred throughout the landscape – overall a net soil loss of 31 Mg ha yr−1 was calculated using 137Cs redistribution techniques. No net depositional sites were observed in the 45 sampling points in the landscape, suggesting that the site was dominated by wind erosion. The high rates of loss were consistent with very low levels of soil organic carbon storage (37 to 46 Mg ha−1 to 45 cm) at all slope positions in the landscape and with the occurrence of sub-soil features in the plough layer. The Solonetzic-influenced soils occupy 38% of the site and have high sodium adsorption ratios (from 18 to 38 in the B horizon) and high soil resistance values as determined with a penetrometer. For the Solonetz and Solodized Solonetz soils these growth-limiting properties occur immediately below the 10-cm plough layer and may constitute a largely irreversible decrease in their productive capacity. Key words: Cesium-137, soil erosion, soil quality, landscape-scale, organic carbon


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