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 field 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, significant (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 significantly higher (p < 0.05) in 0–15 cm across all land-use practices. The ratios of phenolic and amides to polysaccharides were significantly 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.
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
