Infiltration and soil loss changes during the growing season under ploughing and conservation tillage

Decreased water retention and increased runoff and soil loss are of special importance concerning soil degradation of hilly crop fields. In this study, plots under ploughing (conventional) tillage (PT) and conservation tillage (CT; 15 years) were compared. Rainfall simulation on 6 m2 plots was applied to determine infiltration and soil loss during the growing season. Results were compared with those measured from 1200 m2 plots exposed to natural rainfalls in 2016. Infiltration was always higher under CT than PT, whereas the highest infiltration was measured under the cover crop condition. Infiltration under seedbed and stubble resulted in uncertainties, which suggests that natural pore formation can be more effective at improving soil drainage potential than can temporary improvements created by soil tillage operations. Soil erodibility was higher under PT for each soil status; however, the seedbed condition triggered the highest values. For CT, soil loss volume was only a function of runoff volume at both scales. Contrarily, on PT plots, some extreme precipitation events triggered extremely high soil loss owing to linear erosion, which meant no direct connection existed between the scales. Improved soil conditions due to conservation practice are more important for decreasing soil loss than the better surface conditions

Spatial and temporal changes in infiltration and aggregate stability: a case study of a subhumid irrigated cropland

Climate change is increasing the occurrence of extreme precipitation events and causing irregular precipitation patterns. This occurs in parallel with the degradation of crop fields, and triggers the occurrence of pluvial floods and droughts on the same field. Consequently, irrigation must be adapted to the changing soil properties. Detailed spatial and temporal measurements of changes in infiltration are required. This study aimed to quantify changes in infiltration for a subhumid irrigated cropland with various soil types (Phaeozem, Solonetz, Chernozem) and field conditions (seedbed and stubble) by simulating rainfall. As the soil structure determines hydrology, the aggregate stability/surface roughness was tested as a proxy of infiltration through photogrammetry. The soil losses caused by precipitation did not exhibit connections to changes in the surface roughness, and lower aggregate stability did not necessarily cause lower infiltration intensities, suggesting that sedimentation could only partly seal drainage pores. The final infiltration intensities varied within a wide range (0.2−28.4 mm h−1). Seedbed preparation did not increase the volume of micropores (<10 µm), which resulted in higher infiltration under stubble. Photogrammetry was found to be a potentially useful tool for measuring aggregate stability, however, further investigations on in situ soil surfaces are required for technical improvement