2.2.1 Root channels
The area of root channels was characterized using a 64-row multi-slice spiral computed tomography CT scanner (Light Speed VCT, Jiangsu Provincial Hospital of Integrated Traditional Chinese and Western Medicine) (San, Caniego & García, 2017). The images (Figure A.1) were processed by running the ”Intelligent Identification System for Pores in Saline Soil” V1.0 (2018SR074781). The minimum pixel area was set as 1, ie. the minimum identified root channel diameter was 0.298 mm.