Soil water repellency of the artificial soil and natural soil in rocky slopes as affected by the drought stress and polyacrylamide

Zhang Chen; Ruixin Wang; Pengyuan Han; Hailong Sun; Haifeng Sun; Chengjun Li; Lixia Yang

doi:10.1016/j.scitotenv.2017.11.146

Soil water repellency of the artificial soil and natural soil in rocky slopes as affected by the drought stress and polyacrylamide

Sci Total Environ. 2018 Apr 1:619-620:401-409. doi: 10.1016/j.scitotenv.2017.11.146. Epub 2017 Nov 29.

Authors

Zhang Chen¹, Ruixin Wang², Pengyuan Han³, Hailong Sun⁴, Haifeng Sun⁵, Chengjun Li⁶, Lixia Yang⁷

Affiliations

¹ Institute of Loess Plateau, Shanxi University, Taiyuan 030006, PR China. Electronic address: chenzhang@sxu.edu.cn.
² Institute of Loess Plateau, Shanxi University, Taiyuan 030006, PR China.
³ Research Center of Experimental Shanxi Academy of Agricultural Sciences, Taiyuan 030031, PR China.
⁴ State Key Laboratory of Hydraulics and Mountain River Engineering, Sichuan University, Chengdu 610064, PR China.
⁵ College of Environmental & Resource Sciences of Shanxi University, Taiyuan 030006, PR China.
⁶ School of BioSciences, BioSciences 4, University of Melbourne, Royal Parade, Parkville, Melbourne 3052, Australia.
⁷ Administrative Committee of Qingdao Dongjiakou Economic Zone, Qingdao 266409, PR China.

PMID: 29156261
DOI: 10.1016/j.scitotenv.2017.11.146

Abstract

Soil water repellency (SWR) causes reduced soil water storage, enhanced runoff and reduced ecosystem productivity. Therefore, characterization of SWR is a prerequisite for effective environmental management. SWR has been reported under different soils, land uses and regions of the world, particularly in forest land and after wildfires; however, the understanding of this variable in the artificial soil of rocky slope eco-engineering is still rather limited. This study presented the characterization of SWR in the artificial soil affected by the polyacrylamide (PAM) and drought stress. There were two molecular weights of PAM, and the CK was without PAM application. Three types of soil were studied: natural soil and two types of artificial soil which have been sprayed for 1y and 5y, respectively. The drought stress experiments had three drought gradients, lasted for three weeks. Water repellency index (WRI) and soil-water contact angle (β) were determined using intrinsic sorptivity method by measuring the water sorptivity (S_W) and ethanol sorptivity (S_E) in all soil samples. The results showed that (1) Polyacrylamide treatments significantly increased S_W by 3% to 38%, and reduced S_E by 1% to 15%, WRI by 6% to 38%, β by 3% to 23% compared to the control group. Polyacrylamide treatments also increased water-stable aggregates content and total porosity by 22% to 33%, 11% to 20% relative to the control, while PAM with a higher molecular weight performed best. (2) The interaction between PAM and drought stress had a significant effect on WRI and β for all soil types (P<0.01) while it only had a significant effect on S_W and S_E for the artificial soil (P<0.01). (3) The artificial soil had a greater WRI and β than the natural soil.

Keywords: Anionic polyacrylamide; Artificial soil; Drought stress; Steep rocky slope stabilization projects.