Water and salt exchange flux and mechanism in a dry saline soil amended with buried straw of varying thicknesses

• Published in: Geoderma 2020-04, Vol.365, p.114213, Article 114213
• Main Authors: Zhang, Hongyuan, Pang, Huancheng, Zhao, Yonggan, Lu, Chuang, Liu, Na, Zhang, Xiaoli, Li, Yuyi
• Format: Article
• Language: English
• Subjects: China; Saline soils; Salt flux; Soil moisture; Straw layer; Thickness
• ISSN: 0016-7061; 1872-6259
• DOI: 10.1016/j.geoderma.2020.114213

•Soil water significantly decreased with rates of buried straw during the later stage of sunflower.•Salt leaching flux increased with increases in thickness of buried straw.•Adoption of straw barrier affected saturated water conductivity and porosity among layers.•As the years went by, the thicker straw layer increased the upward mobility of salt.•The 5 cm thickness straw layer is more practical for field work in dry saline soil. Salt stress severely constrains crop productivity in arid lands of the world. Burying straw at the 40 cm soil depth plus plastic film mulching could mitigate root zone salinity, but little is known about how the thickness of buried straw affects soil water and salt transport. Therefore, a three-year field experiment was conducted from 2010 to 2013 to address this issue, with treatments including: compacted straw thickness of 3 cm (T3), 5 cm (T5), or 7 cm (T7) (corresponding to straw application at rates of 6, 12 and 18 t ha−1, respectively). In addition, a supplementary experiment, which included treatments of no buried straw layer (CK) and 5 cm of compacted straw layer thickness (t5) in the same micro-plot experiment, was carried out from 2014 to 2016 to identify soil pore structure and hydraulic parameters after three years of deep straw burial. Results showed that the initial soil water content increased with increasing thickness but significantly (P  T7. Although T7 had the most pronounced effect on salt mitigation, it was difficult to implement under normal field conditions. Thus, for relatively good water infiltration, salt leaching and inhibition of salt return, straw buried to a thickness of 5 cm is recommended.