Horizontal and vertical water and solute fluxes in paddy rice fields

Assessment of Chinese paddy-soil structure using X-ray computed tomography

“…At 30 to 45 cm depth, macroaggregates of larger horizontal than vertical extension were formed from clusters of round aggregates of about 1 to 5 mm. This paddy field (O) was cultivated with early rice -early rice for more than 100 years (Janßen et al, 2006;Janssen and Lennartz, 2007).…”

“…7), and was also observed in the soil profiles of field Y when it was not flooded. These structures might cause lateral preferential flow on the plough pan as measured by Janssen and Lennartz (2007). The cracked zone is not recognized for sample O, which was sampled only 3 days after draining the saturated topsoil.…”

“…Visually observed structures are to be discussed by quantitative parameters from X-ray scanning and data processing. Changes of soil structure with depth are discussed by comparing morphological observations with bulk density distributions and impacts on water flow that have been demonstrated by Sander and Gerke (2007) and Janssen and Lennartz (2007).…”

Groundwater impact on methane emissions from flooded paddy fields

“…The clay loam class is chosen because the non-puddled subsoil layers are typically characterized by clayey or loamy textures in paddies [12,30,31,32,33,34,14,35]. The sand class is considered to test the effect of highly permeable subsoils.…”

A new method for indirectly estimating infiltration of paddy fields in situ

“…Lateral seepage (lateral flow/seepage) is the lateral movement of subsurface water of a paddy field. The study revealed the existence of lateral flow through the ridges to the adjacent lower fields (Janssen and Lennartz, 2007). With well-maintained ridges, lateral seepage is generally small (Bouman et al, 2007).…”