Effects of bedrock erosion by tillage on architectures and hydraulic properties of soil and near-surface bedrock

Jiadong Dai; Jianhui Zhang; Haichao Xu; Yong Wang; Guoming Zhang; Yaotao Xu; Xinjia Hu

doi:10.1016/j.scitotenv.2021.148244

Effects of bedrock erosion by tillage on architectures and hydraulic properties of soil and near-surface bedrock

Sci Total Environ. 2021 Oct 10:790:148244. doi: 10.1016/j.scitotenv.2021.148244. Epub 2021 Jun 8.

Authors

Jiadong Dai¹, Jianhui Zhang², Haichao Xu³, Yong Wang⁴, Guoming Zhang⁵, Yaotao Xu⁶, Xinjia Hu⁷

Affiliations

¹ Institute of Mountain Hazards and Environment, Chinese Academy of Sciences and Ministry of Water Conservancy, Chengdu 610041, China; University of Chinese Academy of Sciences, Beijing 100049, China.
² Institute of Mountain Hazards and Environment, Chinese Academy of Sciences and Ministry of Water Conservancy, Chengdu 610041, China. Electronic address: zjh@imde.ac.cn.
³ State Key Laboratory of Simulation and Regulation of Water Cycle in River Basin, China Institute of Water Resources and Hydropower Research, Beijing 100048, China.
⁴ Institute of Mountain Hazards and Environment, Chinese Academy of Sciences and Ministry of Water Conservancy, Chengdu 610041, China; College of Forestry, Sichuan Agricultural University, Chengdu 611130, China.
⁵ Key Laboratory of Environmental Change and Natural Disaster, Ministry of Education, Beijing Normal University, Beijing 100875, China.
⁶ State Key Laboratory Base of Eco-hydraulic Engineering in Arid Area, Xi'an University of Technology, Xi'an 710048, China.
⁷ Max Planck Institute for the Physics of Complex Systems, Nöthnitzer Str. 38, D-01187 Dresden, Germany.

PMID: 34380272
DOI: 10.1016/j.scitotenv.2021.148244

Abstract

Tillage erosion provides an opportunity for the occurrence of bedrock erosion in hilly croplands with shallow soil layer, influencing the hillslope architecture to some extent. In this study, tillage simulation, hydraulic tests and dye-staining tracing were performed to identify the variation in architectures and relevant hydraulic properties of the soil and near-surface bedrock caused by tillage-induced bedrock erosion. Results show that tillage-induced bedrock erosion played an important role in shaping the rock fragment architecture. Under the condition of no-soil cover, the coarse rock fragment content increased from 29.8% to 38.2% when tillage depth increased from 2 to 6 cm. The field-saturated hydraulic conductivity (K_fs) ranged from 18.63 to 23.78 m d^-1 by the Guelph method and 24.26 to 98.46 m d^-1 by the single ring (SR) method, but effects of tillage depth on K_fs did not show a clear pattern. Under the condition of overlying soil layer, the contents of medium, coarse and total rock fragments in soil increased significantly with tillage depth (P < 0.05). Correspondingly, the K_fs for the soil increased significantly with tillage depth (P < 0.05), implying that the higher content of rock fragments due to the greater tillage depth created the more water flow channels. With respect to the near-surface bedrock, the results of dye-staining tracing show that bedrock fragmentation by tillage tended to promote the development of fracture-preferential flow. The infiltration data derived from the SR method show that the K_fs increased by 33.3% to 50.0% after bedrock fragmentation by tillage compared with that for the control treatment, corresponding to the results of dye-staining tracing. These results suggest that tillage-induced bedrock erosion exerts positive effects on infiltration in the soil and near-surface bedrock by increasing preferential channels.

Keywords: Bedrock erosion; Field-saturated hydraulic conductivity; Fracture-preferential flow; Near-surface bedrock; Rock fragment; Tillage erosion.

MeSH terms

Agriculture*
Soil*

Substances

Soil