Impact of short-rotation willow as riparian land-use practice on soil organic carbon fractions and composition from two contiguous wetland systems in the prairie pothole region

Abstract

Evaluating the impact of land-use practices on soil organic carbon (SOC) in the Canadian prairie pothole region (PPR) is of concern due to the potential to sequester carbon and sustaining soil health. In a eld experiment, SOC content, carbon fractions, and chemical composition were assessed under short rotation willow (SRW) plantation in the marginal riparian zones of two PPR wetland sites and compared with adjacent annual crop (AC) and pasture (PA). The SOC, water extractable (WEOC), light fraction (LFOC), and particulate organic carbon (POC) were used to evaluate the content and its fractions, whereas Fourier Transform Infrared (FTIR) spectroscopy was used to characterize the chemical composition. The SOC was higher in PA in both sites; however, signi cant (p < 0.05) only in site B. The SOC, LFOC, and POC followed a similar land-use pattern in both sites, i.e., PA > SRW = AC. The SOC and WEOC were signi cantly higher (p < 0.05) in 0-15 cm across all land-use practices. The ratios of phenolic and amides to polysaccharides were signi cantly higher (p < 0.05) in site A, while aromatic and carboxylic to polysaccharides were lower under SRW in both sites indicated microbial synthesis of these substances. The abundance of SOC functional groups was higher in the subsoil, accompanied by altered spectral properties with depths showing the potential soil organic matter transformation related to carbon fractions changes. The higher alkyl-C to O-alkyl-C ratio at 15-30 cm under SRW suggested a higher degree of decomposition and better SOC stability.

Three years of cover crops management increased soil organic matter and labile carbon pools in a subtropical vegetable agroecosystem

“…Compared to POX‐C and Cmin, WEOC had a weaker correlation with SOC (Figure 2), which is consistent with findings from Haney and Haney (2015) and Shahariar et al. (2022). Only a very small portion of SOM can be mobilized into the WEOC pool (Haney et al., 2012; Zsolnay & Steindl, 1991), hence WEOC might not be a reliable indicator of SOC build‐up and mineralization, at least in our system.…”

“…This interpretation is consistent with the result that cover crop management decreased the ratio of WEOC to WETN relative to its baseline (Figure S1), as microbial degradation generally decreased the C:N ratio of organic matter (Melillo et al, 1989;Zechmeister-Boltenstern et al, 2015). Compared to POX-C and Cmin, WEOC had a weaker correlation with SOC (Figure 2), which is consistent with findings from Haney and Haney (2015) and Shahariar et al (2022). Only a very small portion of SOM can be mobilized into the WEOC pool (Haney et al, 2012;Zsolnay & Steindl, 1991), hence WEOC might not be a reliable indicator of SOC build-up and mineralization, at least in our system.…”

Agroforestry for sustainable production and resilient landscapes

“…Riparian buffer Shahariar et al (2021) evaluated the impacts of landuse practices on soil-organic carbon (SOC) in Canadian prairie pothole region. They addressed the potential concern of carbon sequestration and soil health in riparian areas.…”