@article{MuellerKoszinskiBrenningetal.2011,
  author    = {Mueller, Marina Elsa Herta and Koszinski, Sylvia and Brenning, Alexander and Verch, Gernot and Korn, Ulrike and Sommer, Michael},
  title     = {Within-field variation of mycotoxin contamination of winter wheat is related to indicators of soil moisture},
  series = {Plant and soil},
  volume    = {342},
  journal   = {Plant and soil},
  number    = {1-2},
  publisher = {Springer},
  address   = {Dordrecht},
  issn      = {0032-079X},
  doi       = {10.1007/s11104-010-0695-5},
  pages     = {289 -- 300},
  year      = {2011},
  abstract  = {Humidity is an important determinant of the mycotoxin production (DON, ZEA) by Fusarium species in the grain ears. From a landscape perspective humidity is not evenly distributed across fields. The topographically-controlled redistribution of water within a single field rather leads to spatially heterogeneous soil water content and air humidity. Therefore we hypothesized that the spatial distribution of mycotoxins is related to these topographically-controlled factors. To test this hypothesis we studied the mycotoxin concentrations at contrasting topographic relief positions, i.e. hilltops and depressions characterized by soils of different soil moisture regimes, on ten winter wheat fields in 2006 and 2007. Maize was the preceding crop and minimum tillage was practiced in the fields. The different topographic positions were associated with moderate differences in DON and ZEA concentrations in 2006, but with significant differences in 2007, with six times higher median ZEA and two times higher median DON detected at depression sites compared to the hilltops. The depression sites correspond to a higher topographic wetness index as well as redoximorphic properties in soil profiles, which empirically supports our hypothesis at least for years showing wetter conditions in sensitive time windows for Fusarium infections.},
  language  = {en}
}
@article{LoosElsenbeer2011,
  author    = {Loos, Martin and Elsenbeer, Helmut},
  title     = {Topographic controls on overland flow generation in a forest - An ensemble tree approach},
  series = {Journal of hydrology},
  volume    = {409},
  journal   = {Journal of hydrology},
  number    = {1-2},
  publisher = {Elsevier},
  address   = {Amsterdam},
  issn      = {0022-1694},
  doi       = {10.1016/j.jhydrol.2011.08.002},
  pages     = {94 -- 103},
  year      = {2011},
  abstract  = {Overland flow is an important hydrological pathway in many forests of the humid tropics. Its generation is subject to topographic controls at differing spatial scales. Our objective was to identify such controls on the occurrence of overland flow in a lowland tropical rainforest. To this end, we installed 95 overland flow detectors (OFDs) in four nested subcatchments of the Lutzito catchment on Barro Colorado Island, Panama, and monitored the frequency of overland flow occurrence during 18 rainfall events at each OFD location temporal frequency. For each such location, we derived three non-digital terrain attributes and 17 digital ones, of which 15 were based on Digital Elevation Models (DEMs) of three different resolutions. These attributes then served as input into a Random Forest ensemble tree model to elucidate the importance and partial and joint dependencies of topographic controls for overland flow occurrence. Lutzito features a high median temporal frequency in overland flow occurrence of 0.421 among OFD locations. However, spatial temporal frequencies of overland flow occurrence vary strongly among these locations and the subcatchments of Lutzito catchment. This variability is best explained by (1) microtopography, (2) coarse terrain sloping and (3) various measures of distance-to-channel, with the contribution of all other terrain attributes being small. Microtopographic features such as concentrated flowlines and wash areas produce highest temporal frequencies, whereas the occurrence of overland flow drops sharply for flow distances and terrain sloping beyond certain threshold values. Our study contributes to understanding both the spatial controls on overland flow generation and the limitations of terrain attributes for the spatially explicit prediction of overland flow frequencies.},
  language  = {en}
}