Amos Banin

Mapping of several soil properties using DAIS-7915 hyperspectral scanner data—a case study over clayey soils in Israel

The data acquired from the hyperspectral airborne sensor DAIS-7915 over Izrael Valley in northern Israel was processed to yield quantitative soil properties maps of organic matter, soil field moisture, soil saturated moisture, and soil salinity. The method adopted for this purpose was the Visible and Near Infrared Analysis (VNIRA) approach, which yields an empirical model for predicting the soil property in question from both wet chemistry and spectral information of a representative set of samples (calibration set). Based on spectral laboratory data that show a significant capability to predict the above soil properties and populations using the VNIRA strategy, the next step was to examine this feasibility under a hyperspectral remote sensing (HSR) domain. After atmospherically rectifying the DAIS-7915 data and omitting noisy bands, the VNIRA routine was performed to yield a prediction equation model for each property, using the reflectance image data. Applying this equation on a pixel-bypixel basis revealed images that described spatially and quantitatively the surface distribution of each property. The VNIRA results were validated successfully from a priori knowledge of the area characteristics and from data collected from several sampling points. Following these examinations, a procedure was developed in order to create a soil property map of the entire area, including soils under vegetated areas. This procedure employed a random selection of more than 80 points along non-vegetated areas from the quantitative soil property images and interpolation of the points to yield an isocontour map for each property. It is concluded that the VNIRA method is a promising strategy for quantitative soil surface mapping, furthermore, the method could even be improved if a better quality of HSR data were used.

Determination of organic matter content in arid‐zone soils using a simple “loss‐on‐ignition” method

Abstract A simple and rapid procedure for the determination of organic matter content in mineral soils by loss‐on‐ignition without pretreatment was studied. Attention was given to the possible effect of inorganic compounds abundant in mineral soils on the estimation of organic matter content by this method. Both fast heating (DTA‐TGA type) studies and prolonged heating procedures were employed on natural and “synthetic”; soils. The results were compared to those obtained by the dichromate wet‐oxidation method widely used in soil laboratories for organic matter determination. In a group of 91 soils collected from various mineral soils in Israel, and having OM contents between 0.09 and 13.23%, a correlation coefficient of 0.972 was obtained for the linear regression between organic matter content measured by the proposed method and organic carbon measured by the dichromate wet‐oxidation method.

Scanning Electron Microscope Observations On Soil Crusts And Their Formation

Scanning electron micrographs (SEM) of crusts of loessial soils are presented. SEM observations were performed on crusts formed by raindrop impact at various stages of their formation. The crust structure was compared to the natural undisturbed soil. During the crust formation, a middle-term stage developed at which coarse particles, stripped of the fine ones, composed the surface layer of the soil. At the final stage of the crust formation, the coarse particles were washed away, and a thin seal skin, about 0.1 millimeter thick, formed the uppermost layer of the soil. A depositional crust, which was formed mainly by the translocation of fine particles, was marked by the presence of a thin skin also about 0.1 millimeter thick, suggesting involvement of similar secondary mechanisms of formation. This work illustrates the use of SEM for the study of soil crust formation and structure.

Distribution of natural and anthropogenic lead in Mediterranean soils

Abstract The concentrations and isotopic composition of Pb have been combined with a selective sequential dissolution procedure to track the distribution of anthropogenic and natural Pb in the soil of semiarid climate and the penetration pathway of petrol-Pb within the soil profile. Soil samples were collected from soil profiles adjacent to a major highway (8–23 m) and from soil profiles 500 m away from the same highway. The selective sequential dissolution procedure was used to determine the distribution of Pb between the different soil components: soil carbonate, organic matter, Fe-oxides and hydrous oxides, and aluminosilicates. Natural Pb is associated mainly with aluminosilicates (∼60%) and Fe-oxides (∼30%), and only a small fraction with the soil carbonate and organic matter (∼10%). In contrast to the distribution of natural Pb, the distribution of anthropogenic Pb, which accumulates mainly in the upper part of the soil profile, is ∼40% with the soil carbonate, ∼10% with organic matter, ∼35% with Fe-oxides, and only ∼15% with aluminosilicates. On the basis of concentration and isotopic composition of total Pb, the deeper horizon of the roadside soil (10–30 cm) and the soil sampled 500 m from the highway seem uncontaminated. However, the isotopic composition of the labile components in the soil (Pbcarb, Pborg, and PbFe-ox) indicates that these soils are actually contaminated. This contamination implies that over the period of vehicle pollution (∼40 yr), petrol-Pb has penetrated through the entire roadside soil profile (25–30 cm). Furthermore, Pb isotopes in aluminosilicates of the upper part of the roadside soil indicate that this Pb too is anthropogenic. Measurements of Pb concentration and isotopic composition in roadside soil profiles sampled in 1997 and archived samples collected at the same location in 1982 provided a unique opportunity to trace petrol-Pb penetration into the soil.

A correlative study of the chemical and physical properties of a group of natural soils of Israel.

Data on the chemical and physical properties, i.e., cation exchange capacity, organic matter content, CaCO3 content, clay, silt and sand percentages, moisture content at the hygroscopic, 15 atm, 1/3 atm. and saturated paste states and specific surface area, of a group of soil samples from various locations, representing the main soil types of Israel, were subjected to statistical analysis in order to determine the correlation between pairs of properties, and to formulate quantitative regression equations for the properties that are significantly correlated. Cation exchange capacity was highly correlated with clay content. Organic matter and CaCO3 usually showed small correlation coefficients with the other properties included in the study. The mechanical composition was correlated with both the physical and the chemical properties. The various moisture content “constants” were significantly correlated among themselves and with the chemical properties of the soil. Specific surface area was found to be a valuable characteristic of soils. Because of its simplicity, as well as its prediction value, it is suggested as a key determination for use in the quantitative characterization of soils.

New approach to studies of heavy metal redistribution in soil

Abstract The bioavailability and mobility of heavy metals in soils is dependent upon redistribution processes between solution and solid phases and among solid-phase components. This paper reviews the definitions and applications of two newly developed parameters, the redistribution index and the reduced partitioning parameter, in quantifying redistribution processes of heavy metals in contaminated soils. The redistribution index depicts the removal/attainment of metal-contaminated soils from/to the fractional distribution pattern characteristic of non-amended soils, while the reduced partitioning parameter quantifies the relative binding intensity of heavy metals in soils. Over time, metal salt-spiked and sludge-amended soils approached the fractional distribution pattern of non-amended soils. The rates of redistribution of metals and their binding intensity in soils were affected by the metal species, loading levels and soil properties. Metals in contaminated soils at low loading levels approach the fractional distribution pattern of non-amended soil more rapidly than those at high loading levels. The sequence order of approach by metals to the fractional distribution pattern of non-amended soil was: Cd>Cu>Ni=Zn>Cr. In both non-amended and contaminated soils, Cr had the highest binding intensity, Cd the lowest, and Cu, Ni and Zn, intermediate values. In addition to our own data, primarily on metal salt-spiked soils, these two indices are also used to evaluate redistribution processes of heavy metals in sewage sludge-amended soils from other published reports.

Near infrared analysis (NIRA) as a method to simultaneously evaluate spectral featureless constituents in soils

High resolution diffuse reflectance spectra (3113 spectral points) in the near infrared region (NIR) were recorded for 91 soil samples from Israel. Ten soil constituents (total iron [Fe2O3], aluminum [Al2O2], potassium [K2O], and phosphorous [P2O2], loss on ignition residual [LOI], free iron oxides [Fed], aggregate size (1.5–2mm) fraction [F1], average aggregate size (mm) [AVGR], and sodium adsorption percentages [CNaP]) were measured by routine methods employed in soil laboratories. An empirical model to predict each property from its reflectance spectrum in the near infrared spectral region was developed by adapting the near infrared analysis (NIRA) technique. Several data manipulations were used in order to obtain optimum performance. The optimum performance of several soil constituents was found to be at 3113 spectral points (Al2O3, Fed, and K2O) and 310 spectral points (Fe2O3), whereas for others (SiO2, AVGR, and F1) even 25 spectral points provided sufficient performance. Strong support for the capability of NIRA was obtained by a careful examination of the possible correlation between spectrally active soil properties (clay content [CLAY], specific surface area [SSA], hygroscopic moisture [HIGF] and calcite [CaCO3]), which were studied elsewhere, and the featureless constituents studied here. A slight bias was found for the prediction of Al2O3 and Fed, and a greater bias was found for K2O, suggesting that further study regarding the prediction of these constituents is needed. It was concluded that NIRA is a very promising vehicle for rapid and nonrestrictive analysis of soil materials.

Long-term transformations and redistribution of potentially toxic heavy metals in arid-zone soils incubated: I. Under saturated conditions

Solid-phase transformations of Cd, Cu, Cr, Ni and Zn, added as soluble salts at several levels to two arid-zone soils, were studied over a period of one year. The soils were maintained under a saturated-paste regime and sampled periodically. A selective sequential dissolution procedure was employed to determine the changes in metal distribution among six operationally defined solid-phase fractions. A function,Uts was introduced to measure the fractional attainment of equilibrium of the soils following a perturbation. The direction and rate of redistribution of the added metals in the soils were affected by the nature of the metal, the soil properties and the metal loading level. Cd added to the soils was transferred from the exchangeable (EXC) into the carbonate (GARB) fraction. When soluble Cu, Cr, Ni and Zn were added at low loading levels, metals were transferred from the reducible oxides(RO) bound and easily reducible oxides (ERO) bound fractions and the EXC fraction, into the CARB fraction. However, at the higher loading level, metals were transferred from the EXC and CARB fractions into the organic matter bound (OM), ERO and RO fractions. TheUts function approached lower values as incubation continued but remained removed from 1. The overall flux of metals among fractions was the combined result of the readjustment of the metals in the native soil to changing conditions due to saturation, and the transfer of added soluble metals to the less labile fractions.

Nature, formation and effects of soil crusts formed by water drop impact

Abstract Research was conducted to investigate: (1) the structure, formation and nature of soil crusts which develop as a result of raindrop impact under controlled conditions of simulated rain, and (2) the crust effect on infiltration rates. Scanning electron microscope (SEM) observations performed on sandy, sandy-loam and clayey soil samples show the crust to be composed of two layers: (1) a “skin”, 0.1 mm thick, and (2) a layer, 2–3 mm thick, with a higher bulk density in which aggregates have been destroyed. A “washing-in” zone described by earlier investigators could not be detected. The soil beneath the crust maintains its original structure and particle orientation. The chemical composition of the rain water was found to have a significant but not very large effect on the infiltration rate vs. cumulative rain curve of the clayey soil material only; final infiltration rate was about 20% lower when distilled water was applied compared to tap water (electrical conductivity ≈ 0.6 mmho cm−1). An increase of the bulk density from 1.35–1.48 g cm−3 in undisturbed soil to 1.74–1.88 g cm−3 in crusts was found. The amount of eroded material increased gradually with increase of runoff and decrease of infiltration. At steady state the erosion rates were 0.45, 1.25, and 0.76 g m−2 min−1 in the sandy, sandy-loam and clayey soil specimens, respectively. Percentages of clay and silt in the eroded material were higher than in the bulk samples. Three stages to describe the changes in nature and effects of crusts during their formation are suggested: (1) the rate of infiltration decreases to a point at which runoff beings, (2) the initiation of runoff until infiltration and runoff rates become stabilized, and (3) infiltration and runoff maintain steady rates.

Selective sequential dissolution techniques for trace metals in arid-zone soils : the carbonate dissolution step

Abstract Dissolution capacity and kinetics of carbonates by sodium acetate (NaOAc)‐acetic acid (HOAc) at various pHs were studied. A comparative study of the selectivity, specificity, and effectivity of NaOAc‐HOAc solution on carbonate bound fraction during the sequential selective dissolution procedure was conducted by comparing the dissolution of major and trace elements from arid zone soils by this buffer solution at various pHs. The effect of the pH of NaOAc‐HOAc solution on the following fractions in the sequential selective dissolution procedure was also studied. NaOAc‐HOAc solution at pH 5.5 at a soil to solution ratio of 1:25, can dissolve all the carbonate from calcareous soils with 10–20% of carbonate; at pH 5.0 it can dissolve all the carbonate in soils with about 30–50% calcium carbonate (CaCO3). A second extraction with fresh buffer solution at pH 5.0 is required for soils with more than 50% of carbonate. Six hours of extraction time is generally sufficient for complete carbonate dissolution....