Details
| Original language | English |
|---|---|
| Article number | 180162 |
| Journal | Vadose zone journal |
| Volume | 18 |
| Issue number | 1 |
| Publication status | Published - 2019 |
| Externally published | Yes |
Abstract
During preferential flow in structured soils, solute transport is largely restricted to a complex network of macropores. Clay-organic coatings of macropore surfaces determine soil physicochemical properties relevant for mass transport and carbon and nutrient turnover, such as the cation exchange capacity (CEC). However, due to the lack of an appropriate measurement approach, the small-scale spatial distributions of the CEC and its quantities are unknown to date. The objective of this work was to develop a method for predicting the millimeter- to centimeter-scale, twodimensional spatial distribution of the CEC at intact macropore surfaces. Diffuse reflectance infrared Fourier transform (DRIFT) spectroscopy was used to analyze bulk soil and separated coating material and for intact macropore surfaces as DRIFT mapping. To determine effective CEC (CECeff), a reduction of soil mass down to 0.5 g for use in the standard barium chloride batch method was tested to account for the limited amount of soil material that can be separated from thin macropore coatings. Linear and partial least squares regression analyses were applied to predict the CECeff distribution at intact macropore surfaces for samples from Luvisol Bt horizons from loess (L) and glacial till (T) using DRIFT spectral data. The highest CECeff values were found for coatings and pinhole fillings rich of clay-organic material (L: 38 cmol kg-1; T: 29 cmol kg-1) compared with low CECeff values of uncoated cracks and earthworm burrows that were similar to those of bulk soil (L: 21 cmol kg-1; T: 14 cmol kg-1). The location of millimeter- to centimeter-sized regions with increased CECeff levels at intact macropore surfaces corresponded with the location of clay-organic coatings. The proposed method allows determining the CEC at macropore surfaces to quantify their effect on nutrient transport by preferential flow as well as on plant nutrient supply in macropores that may serve as preferential growth paths for plant roots.
ASJC Scopus subject areas
- Agricultural and Biological Sciences(all)
- Soil Science
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In: Vadose zone journal, Vol. 18, No. 1, 180162, 2019.
Research output: Contribution to journal › Article › Research › peer review
}
TY - JOUR
T1 - Determining millimeter-scale maps of cation exchange capacity at macropore surfaces in Bt horizons
AU - Leue, Martin
AU - Beck-Broichsitter, Steffen
AU - Felde, Vincent J.M.N.L.
AU - Gerke, Horst H.
N1 - Publisher Copyright: © 2019 The Author(s).
PY - 2019
Y1 - 2019
N2 - During preferential flow in structured soils, solute transport is largely restricted to a complex network of macropores. Clay-organic coatings of macropore surfaces determine soil physicochemical properties relevant for mass transport and carbon and nutrient turnover, such as the cation exchange capacity (CEC). However, due to the lack of an appropriate measurement approach, the small-scale spatial distributions of the CEC and its quantities are unknown to date. The objective of this work was to develop a method for predicting the millimeter- to centimeter-scale, twodimensional spatial distribution of the CEC at intact macropore surfaces. Diffuse reflectance infrared Fourier transform (DRIFT) spectroscopy was used to analyze bulk soil and separated coating material and for intact macropore surfaces as DRIFT mapping. To determine effective CEC (CECeff), a reduction of soil mass down to 0.5 g for use in the standard barium chloride batch method was tested to account for the limited amount of soil material that can be separated from thin macropore coatings. Linear and partial least squares regression analyses were applied to predict the CECeff distribution at intact macropore surfaces for samples from Luvisol Bt horizons from loess (L) and glacial till (T) using DRIFT spectral data. The highest CECeff values were found for coatings and pinhole fillings rich of clay-organic material (L: 38 cmol kg-1; T: 29 cmol kg-1) compared with low CECeff values of uncoated cracks and earthworm burrows that were similar to those of bulk soil (L: 21 cmol kg-1; T: 14 cmol kg-1). The location of millimeter- to centimeter-sized regions with increased CECeff levels at intact macropore surfaces corresponded with the location of clay-organic coatings. The proposed method allows determining the CEC at macropore surfaces to quantify their effect on nutrient transport by preferential flow as well as on plant nutrient supply in macropores that may serve as preferential growth paths for plant roots.
AB - During preferential flow in structured soils, solute transport is largely restricted to a complex network of macropores. Clay-organic coatings of macropore surfaces determine soil physicochemical properties relevant for mass transport and carbon and nutrient turnover, such as the cation exchange capacity (CEC). However, due to the lack of an appropriate measurement approach, the small-scale spatial distributions of the CEC and its quantities are unknown to date. The objective of this work was to develop a method for predicting the millimeter- to centimeter-scale, twodimensional spatial distribution of the CEC at intact macropore surfaces. Diffuse reflectance infrared Fourier transform (DRIFT) spectroscopy was used to analyze bulk soil and separated coating material and for intact macropore surfaces as DRIFT mapping. To determine effective CEC (CECeff), a reduction of soil mass down to 0.5 g for use in the standard barium chloride batch method was tested to account for the limited amount of soil material that can be separated from thin macropore coatings. Linear and partial least squares regression analyses were applied to predict the CECeff distribution at intact macropore surfaces for samples from Luvisol Bt horizons from loess (L) and glacial till (T) using DRIFT spectral data. The highest CECeff values were found for coatings and pinhole fillings rich of clay-organic material (L: 38 cmol kg-1; T: 29 cmol kg-1) compared with low CECeff values of uncoated cracks and earthworm burrows that were similar to those of bulk soil (L: 21 cmol kg-1; T: 14 cmol kg-1). The location of millimeter- to centimeter-sized regions with increased CECeff levels at intact macropore surfaces corresponded with the location of clay-organic coatings. The proposed method allows determining the CEC at macropore surfaces to quantify their effect on nutrient transport by preferential flow as well as on plant nutrient supply in macropores that may serve as preferential growth paths for plant roots.
UR - http://www.scopus.com/inward/record.url?scp=85067241953&partnerID=8YFLogxK
U2 - 10.2136/vzj2018.08.0162
DO - 10.2136/vzj2018.08.0162
M3 - Article
AN - SCOPUS:85067241953
VL - 18
JO - Vadose zone journal
JF - Vadose zone journal
SN - 1539-1663
IS - 1
M1 - 180162
ER -