A comparison of soil properties under four vegetation units from six metalliferous hills in Katanga

Conference (2013, April 12)

In Katanga (Democratic Republic of Congo), numerous metalliferous hills are distributed along what is called the copperhill belt from Kolwezi to Lubumbashi. Very specific vegetation developed on these ... [more ▼]

In Katanga (Democratic Republic of Congo), numerous metalliferous hills are distributed along what is called the copperhill belt from Kolwezi to Lubumbashi. Very specific vegetation developed on these hills within the miombo forest in response to very specific soil conditions, among which the copper content. Previous studies have already shown the existence of gradients of copper from the mineralized rocks outcropping at the top of the hills to the foot slopes on colluviums. After a characterization of the vertical variability of soil properties in pits distributed along the main slopes, we investigated the soil-vegetation relationships in six hills located between the towns of Tenke and Fungurume. Observation 1-square meter plots were installed in four vegetation units and sixty of them were selected according to their relative importance on the six hills. The soil from the top 10cm was sampled and analyzed for pH, Total Organic Carbon, available P, K, Mg, Ca, Cu, Co and Mn and soluble Cu and Co. Analysis of variance was performed in order to assess whether the effects of the “Hill” and of the “Vegetation Unit” were significant to explain soil chemical variability. Additionally, short transects were sampled at the boundaries from adjacent vegetation units in order to evaluate the gradual or rough nature of change in soil properties under these units. [less ▲]

Relationships between soil properties and contents in trace elements in a landscape impacted by atmospheric fallouts in Belgium

Conference (2013, April 08)

Relationships between the P status of surface and deep horizons of agricultural soils under various cropping systems and for different soil types: a case study in Belgium

in Soil Use and Management (2013), 29(S1), 103--113

Application of phosphorus (P) fertilizers to agricultural soils should be based on sound knowledge about soil P reserves, availability and lability to optimize conditions for plant uptake while limiting P ... [more ▼]

Application of phosphorus (P) fertilizers to agricultural soils should be based on sound knowledge about soil P reserves, availability and lability to optimize conditions for plant uptake while limiting P transport to surface waters. This study investigated relationships between parent material (PM), land use and P fractions in agricultural soils at a regional scale. Surface and deep (100–120 cm) soil samples were collected from 120 agricultural sites (240 total samples) and analysed for three P forms (inorganic, organic and available) as well as for additional key properties. Land uses within the study area were continuous cropland, permanent pasture and temporary grassland. The area covered the 12 most common parent types in Wallonia. Mean total P contents were 904 and 401 mg/kg in surface and deep samples, respectively, with a 33% coefficient of variation for both horizons. The organic P fraction represented, on average, 30% of total P, while available P corresponded to 9% of total P. The influence of PM was apparent in both the surface and deep soil samples, while land use influenced only surface properties. The pattern in total P content relative to land use was pasture ≥ cropland ≥ temporary grassland. Correlation analyses highlighted significant relationships between edaphic parameters viz Alox, Feox, CEC, TOC, pH and P content, the main soil parameter being Alox which determines P sorption capacity. An enrichment factor was used to distinguish between geogenic sources and human activities in terms of topsoil P content. [less ▲]

Mapping of the occurrence of phreatic groundwater or karst-sensitive rocks at less than one meter depth in Wallonia, based on the interpretation of the Digital Soil Map of Wallonia

Report (2013)

Spatial distribution of erosion and deposition on an agricultural watershed

in Geophysical Research Abstracts (2013), 15

To better understand the agricultural landscapes evolution becomes an essential preoccupation and, for this, it is needed to take into account the sediments deposition, in a distributed way. As it is not ... [more ▼]

To better understand the agricultural landscapes evolution becomes an essential preoccupation and, for this, it is needed to take into account the sediments deposition, in a distributed way. As it is not possible in practice to study all terrestrial surfaces in detail by instrumenting sectors to obtain data, models of prediction are valuable tools to control the current problems, to predict the future tendencies and to provide a scientific base to the political decisions. In our case, a landscape evolution model is needed, which aims at representing both erosion and sedimentation and dynamically adjusts the landscape to erosion and deposition by modifying the initial digital elevation model. The Landsoil model (Landscape design for Soil conservation under soil use and climate change), among others, could fulfil this objective. It has the advantage to take the soil variability into account. This model, designed for the analysis of agricultural landscape, is suitable for simulations from parcel to catchment scale, is spatially distributed and event-based. Observed quantitative data are essential (notably to calibrate the model) but still limited. Particularly, we lack observations spatially distributed on the watershed. For this purpose, we choose a watershed in Belgium (Wallonia) which is a 124 ha agricultural zone in the loamy region. Its slopes range from 0% to 9%. To test the predictions of the model, comparisons will be done with: - sediment measurements which are done with water samplings in four points on the site to compare the net erosion results; - sediment selective measurements (depth variation observed along graduated bares placed on site) to compare the erosion and deposition results; - very accurate DSM’s (6,76 cm pixel resolution X-Y) obtained by the drone (Gatewing X100) each winter. Besides planning what the landscape evolution should be, a revision of the soil map (drew in 1958) is organized to compare with the past situation and establish how the landscape moved in 50 years. The first results of the sediment measurements and of the pictures of the drone will be showed in the presentation. [less ▲]

Mobility and distribution of lead, cadmium, copper and zinc in soil profiles in the peri-urban market garden of Kunming, Yunnan Province, China

in Archives of Agronomy and Soil Science (2013)

Our soil map as cultural heritage: what of the Belgium soil survey project should be preserved and what is being lost?

Poster (2012, July 06)

Between 1947 and 1991, soils of Belgium were mapped to establish a systematic inventory of the country soil resources. Field observations were done by soil auger to a standard depth of 1.25 m and at a ... [more ▼]

Between 1947 and 1991, soils of Belgium were mapped to establish a systematic inventory of the country soil resources. Field observations were done by soil auger to a standard depth of 1.25 m and at a mean density of 2 points per hectare. Cadastral plans at scale 1:5,000 where used for georeferencing field observations and for delimiting map units, subsequently generalized on the 1:10,000 topographic base map. The final map was published on sheets at scale 1:20,000 along with descriptive texts. Besides, data on about 15,000 described and analyzed soil profiles were reported in technical annexes. With the advent of computers, data on soil profiles have been transfered into relational databases and soil sheets have been digitized. Coding of the data rendered them more accessible, but inevitably implied a standardization and hence a reduction of some information. Still most of the soil surveyors have already passed away, besides their intangible expert knowledge, a wealth of information is also being lost when their field notes, unpublished reports, minutes of meetings and draft maps are being disregarded. The map legend was developed during the first decade of the survey, reflecting state of knowledge on soil formation and their relative importance for agricultural land-use in the 1950s. To guarantee that future generations will be able to appreciate the value and concepts underpinning the soil information, it is important that at least a minimum set of such historical documents would be preserved, analyzed and documented. [less ▲]

Spatial distribution of metallic trace elements in soils contaminated by atmospheric fallouts. Case study: Sclaigneaux (Belgium)

Conference (2012, July 03)

The valleys of Sambre and Meuse in Wallonia hosted numerous metal ore treatment factories. They engendered a contamination of soils by metallic trace elements that may migrate in the landscape through ... [more ▼]

The valleys of Sambre and Meuse in Wallonia hosted numerous metal ore treatment factories. They engendered a contamination of soils by metallic trace elements that may migrate in the landscape through erosion, lixiviation, biological transportation, aso. We investigated the spatial distribution of some metallic trace elements in soils around a former zinc-ore treatment plant to a distance of 3km. The sampling strategy aimed at (i) verifying that the main source of trace elements was the plant chimney, (ii) assessing the impact of the wind directions on fallout dispersion and (iii) evaluating whether there were differences of contents according to soil types and to soil occupation. Two hundred and fifty topsoil samples were collected according to a stratified design dealing with distance to the chimney, direction of dominant winds, soil type, and land use. Pseudo-total contents in inorganic elements, pH, TOC, and N were determined in the laboratory. Besides, classical statistical analysis (i) ANCOVA (three-way ANOVA with the distance as a co-variate) and (ii) Principal Component Analysis were also performed. First results show that (i) zinc, lead and cadmium contents are closely correlated to each other and (ii) negatively correlated with the distance. If the geographical location is the major driving factor of trace elements contents in soils, significant differences were also found between soil type and land use (p-value<0.05). The highest MTE concentrations were associated with North-East winds, forest cover and pebbles rich soils. Further investigations will concern the vertical and toposequential distributions, and the speciation of MTE. [less ▲]

Is a zero P-input compatible with a sustainable agriculture? Long-term field experiments in loamy soils.

Poster (2012, July)

Can early stages concentrations be usefull tools to enhance the prediction of trace metal uptake by vegetables grown on contaminated soils?

Poster (2012, July)