TY  - JOUR
A1  - Scheffler, Raphael
A1  - Neill, Christopher
A1  - Krusche, Alex V.
A1  - Elsenbeer, Helmut
T1  - Soil hydraulic response to land-use change associated with the recent soybean expansion at the Amazon agricultural frontier
JF  - Agriculture, ecosystems & environment : an international journal for scientific research on the relationship of agriculture and food production to the biosphere
N2  - Clearing for large-scale soy production and the displacement of cattle-breeding by soybeans are major features of land-use change in the lowland Amazon that can alter hydrologic properties of soils and the runoff generation over large areas. We measured infiltrability and saturated hydraulic conductivity (Ksat) under natural forest, pasture, and soybeans on Oxisols in a region of rapid soybean expansion in Mato Grosso, Brazil. The forest-pasture conversion reduced infiltrability from 1258 to 100 mm/h and Ksat at all depths. The pasture-soy conversion increased infiltrability from 100 to 469 mm/h (attributed to shallow disking), did not affect Ksat at 12.5 cm, but decreased Ksat at 30 cm from 122 to 80 mm/h, suggesting that soybean cultivation enhances subsoil compaction. Permeability decreased markedly with depth under forest, did not change under pasture, and averaged out at one fourth the forest value under soybeans with a similar pattern of anisotropy. Comparisons of permeability with rainfall intensities indicated that land-use change did not alter the predominantly vertical water movement within the soil. We conclude that this landscape is well buffered against land-use changes regarding near-surface hydrology, even though short-lived ponding and perched water tables may occur locally during high-intensity rainfall on pastures and under soybeans.
KW  - Land-cover change
KW  - Tropical forest
KW  - Pasture
KW  - Infiltrability
KW  - Saturated hydraulic conductivity
KW  - Ksat
KW  - Hydrological flowpaths
Y1  - 2011
U6  - https://doi.org/10.1016/j.agee.2011.08.016
SN  - 0167-8809
VL  - 144
IS  - 1
SP  - 281
EP  - 289
PB  - Elsevier
CY  - Amsterdam
ER  - 
TY  - JOUR
A1  - Zimmermann, Alexander
A1  - Schinn, Dustin S.
A1  - Francke, Till
A1  - Elsenbeer, Helmut
A1  - Zimmermann, Beate
T1  - Uncovering patterns of near-surface saturated hydraulic conductivity in an overland flow-controlled landscape
JF  - Geoderma : an international journal of soil science
N2  - Saturated hydraulic conductivity (K-s) is an important soil characteristic affecting soil water storage, runoff generation and erosion processes. In some areas where high-intensity rainfall coincides with low K-s values at shallow soil depths, frequent overland flow entails dense drainage networks. Consequently, linear structures such as flowlines alternate with inter-flowline areas. So far, investigations of the spatial variability of K-s mainly relied on isotropic covariance models which are unsuitable to reveal patterns resulting from linear structures. In the present study, we applied two sampling approaches so as to adequately characterize K-s spatial variability in a tropical forest catchment that features a high density of flowlines: A classical nested sampling survey and a purposive sampling strategy adapted to the presence of flowlines. The nested sampling approach revealed the dominance of small-scale variability, which is in line with previous findings. Our purposive sampling, however, detected a strong spatial gradient: surface K-s increased substantially as a function of distance to flowline; 10 m off flowlines, values were similar to the spatial mean of K-s. This deterministic trend can be included as a fixed effect in a linear mixed modeling framework to obtain realistic spatial fields of K-s. In a next step we used probability maps based on those fields and prevailing rainfall intensities to assess the hydrological relevance of the detected pattern. This approach suggests a particularly good agreement between the probability statements of K-s exceedance and observed overland flow occurrence during wet stages of the rainy season.
KW  - Soil hydrology
KW  - Saturated hydraulic conductivity
KW  - Overland flow generation
KW  - Spatial patterns
KW  - Drainage network
Y1  - 2013
U6  - https://doi.org/10.1016/j.geoderma.2012.11.002
SN  - 0016-7061
VL  - 195
IS  - 169
SP  - 1
EP  - 11
PB  - Elsevier
CY  - Amsterdam
ER  -