TY - JOUR
T1 - Soil-water repellency characteristic curves for soil profiles with organic carbon gradients
AU - Wijewardana, Nadeeka Senani
AU - Müller, Karin
AU - Moldrup, Per
AU - Clothier, Brent
AU - Komatsu, Toshiko
AU - Hiradate, Syuntaro
AU - de Jonge, Lis Wollesen
AU - Kawamoto, Ken
N1 - Funding Information:
This research project was supported by a JSPS/MBIE Bilateral Research Program ( FY2013-FY2014 ) between New Zealand and Japan.
Publisher Copyright:
© 2015 Elsevier B.V.
PY - 2016/2/15
Y1 - 2016/2/15
N2 - Soil water repellency (SWR) of soils is a property with significant consequences for agricultural water management, water infiltration, contaminant transport, and for soil erosion. It is caused by the presence of hydrophobic agents on mineral grain surfaces. Soils were samples in different depths at three forest sites in Japan and three pasture sites in New Zealand, covering soil organic carbon (SOC) contents between 1 and 26%. The SWR was measured over a range of water contents by three common methods; the water drop penetration time (WDPT) test, the molarity of an ethanol droplet (MED) method, and the sessile drop method (SDM). The aim to (i) compare the methods, (ii) characterize the soil-water repellency characteristic curves (SWRCC) being SWR as a function of the volumetric soil-water content (θ) or matric potential (ψ), and (iii) find relationships between SWRCC parameters and SOC content. The WDPT, MED, and SDM generally agreed well in predicting the θ range where SWR occurred, and there was close agreement between SWR results determined by average MED and SDM at similar θ. Generally, SWR was only found within the top 20cm of the soil profiles. Six SWR parameters were introduced: (i) the area under the curve (SWR(θ)); (ii) θ at the maximum SWR (θWR-max), (iii) θ where SWR ceased (θnon-WR), (iv) the maximum SWR (CAi-max), (v) pF at the maximum SWR (pFWR-max) and (vi) pF where SWR ceased (pFnon-WR). The relationship between the first three parameters and SOC content were best described with Langmuir type equations (r2 of 0.5-0.7), while the other three parameters changed linearly with SOC contents.
AB - Soil water repellency (SWR) of soils is a property with significant consequences for agricultural water management, water infiltration, contaminant transport, and for soil erosion. It is caused by the presence of hydrophobic agents on mineral grain surfaces. Soils were samples in different depths at three forest sites in Japan and three pasture sites in New Zealand, covering soil organic carbon (SOC) contents between 1 and 26%. The SWR was measured over a range of water contents by three common methods; the water drop penetration time (WDPT) test, the molarity of an ethanol droplet (MED) method, and the sessile drop method (SDM). The aim to (i) compare the methods, (ii) characterize the soil-water repellency characteristic curves (SWRCC) being SWR as a function of the volumetric soil-water content (θ) or matric potential (ψ), and (iii) find relationships between SWRCC parameters and SOC content. The WDPT, MED, and SDM generally agreed well in predicting the θ range where SWR occurred, and there was close agreement between SWR results determined by average MED and SDM at similar θ. Generally, SWR was only found within the top 20cm of the soil profiles. Six SWR parameters were introduced: (i) the area under the curve (SWR(θ)); (ii) θ at the maximum SWR (θWR-max), (iii) θ where SWR ceased (θnon-WR), (iv) the maximum SWR (CAi-max), (v) pF at the maximum SWR (pFWR-max) and (vi) pF where SWR ceased (pFnon-WR). The relationship between the first three parameters and SOC content were best described with Langmuir type equations (r2 of 0.5-0.7), while the other three parameters changed linearly with SOC contents.
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U2 - 10.1016/j.geoderma.2015.10.020
DO - 10.1016/j.geoderma.2015.10.020
M3 - Article
AN - SCOPUS:84946037331
VL - 264
SP - 150
EP - 159
JO - Geoderma
JF - Geoderma
SN - 0016-7061
ER -