Expansive soil-biochar-root-water-bacteria interaction: Investigation on crack development, water management and plant growth in green infrastructure

Abstract

The objectives of the study are to explore fundamental mechanism of expansive soil-biochar-root-water-bacteria interaction, and investigate crack development and hydraulic properties of biochar amended soils aiming at green infrastructures. The physical, chemical and biological effects of biochar on expansive soil have been comprehensively explored. Crack development is investigated quantificationally, and mechanism of soil damage evolution is briefly discussed base on micro-chemical analyses. During outdoor vegetation period, photosynthesis light response curves were measured to evaluate plant growth. After period of vegetation, hydraulic properties of root-soil composites and unplanted soils were compared. The study reveals that soil crack intensity factor decreases by 33.5%, 48.5% and 47.3% due to 5%, 10% and 15% biochar introduction respectively after 5 wetting-drying cycles. 15% biochar amendment helps to restrain both initiation and propagation of soil cracks. Biochar amendment of up to 5% contributes well to residual water content and plant growth (i.e., light saturation point and light compensation point). Excessive biochar addition would restrain roots elongation, and increase saturated water content. Spatial root distribution is changed due to biochar addition, which further influences hydraulic properties and crack development. Hydraulic conductivity and soil dry density share negative correlations, 5% biochar enhances hydraulic conductivity remarkably at relatively loose condition. Biochar amendment also contributes to preventing nitrogen loss and forming more complex bacterial community in soils. The study adds to our knowledge of physio-chemical interactions of biochar with expansive clay, vegetation, water and microorganism.

Plant Growth on a Mediterranean Green Roof: A Pilot Study on Influence of Substrate Depth, Substrate Composition, and Type of Green Roof

“…Other studies have demonstrated that other characteristics of the growing medium, like its organic content, nutrients or pH, are important (Nagase and Dunnett, 2011;Bates et al, 2013;Kotsiris et al, 2013;Thuring and Dunnett, 2014;Tassoula et al, 2015;Papafotiou et al, 2016;McAlister and Rott, 2019). Further studies have investigated the influence of different types of substrates (A'saf et al, 2020;Paraskevopoulou et al, 2021), or other parameters relating with the substrate like the role of bacteria in the soil (Xie et al, 2020;Wang et al, 2021), on plant performance, or on the functions of green roofs (Naranjo et al, 2020). Bates et al (2013) investigated vegetation development on low-fertility growth substrates emulating brownfields and their responses to drought conditions.…”

Influence of Sustainable Biochars Produced from Kitchen Waste, Pig Manure, and Wood on Soil Erosion

“…Historically, erosion studies about soil-biochar composite mainly discuss the influence of biochar characteristics, such as biochar percentage [49,53] and biochar particle size [56]. There are studies that exist on studying the influence of the type of biochar on the performance of green infrastructure, including water retention [57,58], nutrient leaching mitigation [59], and pollutant removal from runoff [60]. However, few studies have documented the effects of different types of biochar on erosion, runoff, and infiltration [61,62].…”

A Survey of Trends and Developments in Green Infrastructure Research

“…First, the idea and fundamental value of GI have been the major emphasis of much research. By looking for publications on GI in four different databases, including books, documents from global agencies, Web of Science (WOS), research institutes, and federal agencies up to 2016, Wang, Zhang, Gan, Liu, and Mei [17] provided a summary of green infrastructure's growth up to that point; they also stressed the significance if multi-function for the analysis and design of GI. Second, a subfield of green infrastructure has been the subject of a comprehensive scholarly analysis.…”