Soil Enzyme Activity as Affected by Land-Use, Salinity, and Groundwater Fluctuations in Wetland Soils of the Prairie Pothole Region

Shayeb Shahariar,Angela Bedard-Haughn,Raju Soolanayakanahally,Bobbi Helgason

doi:10.1007/s13157-021-01431-8

Shayeb Shahariar, Angela Bedard-Haughn + Show 2 more

Open Access

https://doi.org/10.1007/s13157-021-01431-8

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Abstract

Land-use change and climatic variability are significant drivers for the loss of ecosystem services and soil quality in the prairie pothole region (PPR) wetland systems. Land-use induced changes in groundwater table and salinity may influence biogeochemical processes facilitated by extracellular enzymes (EEs) involved in soil organic matter (SOM) decomposition. The effects of changing groundwater table and salinity on β-glucosidase (BG), N-acetyl glucosaminidase (NAG), and alkaline phosphatase (AP) activities were assessed in wetland soils collected from three different adjacent riparian land-use practices in the PPR. In a microcosm study conducted over ten weeks, soils were treated with groundwater salinity (control, 6 mS cm−1, and 12 mS cm−1) and declining groundwater table depths. Extracellular enzyme activities (EEAs) differed significantly (p < 0.05) among soils from different land-uses and between groundwater table depths. The impact of groundwater salinity on soil EEAs were non-significant (p > 0.05). Soil EEAs were significantly higher in soils from pasture, suggesting that the land-use effects resulted from background SOC and TN. Soil EEAs significantly (p < 0.05) reduced under a deeper groundwater table depth, except reverse for BG in site B, indicated that the lowered groundwater table could lead to transitory drought stress for SOM decomposers.Graphical Abstract

Highlights

Extracellular enzymes (EEs) facilitated by microorganisms to acquire energy and nutrients (Sinsabaugh et al 2009; Wallenstein and Burns 2011), are the primary mediators of biogeochemical cycling through soil organic matter (SOM) decomposition (Sinsabaugh et al 2008; Burns et al 2013; Luo et al 2017)
The results of this study suggest that land-use practice had the most significant impact on soil enzyme activities (EEAs)
Higher EEAs in soils from PA point to the higher soil organic carbon (SOC) turnover from the past land-use practices, while no significant difference was observed between annual crop (AC) and Short rotation willow (SRW) due to non-distinguishable variabilities background SOC and Total nitrogen (TN) content of our experimental soil

Summary

Introduction

Extracellular enzymes (EEs) facilitated by microorganisms to acquire energy and nutrients (Sinsabaugh et al 2009; Wallenstein and Burns 2011), are the primary mediators of biogeochemical cycling through soil organic matter (SOM) decomposition (Sinsabaugh et al 2008; Burns et al 2013; Luo et al 2017). With its semi-arid climate, the PPR is composed of a hydrologically distinct and highly sensitive wetland ecosystem that is vulnerable to land-use and climate change (Johnson et al 2005; Johnson et al 2010; Werner et al 2013). Soils of this region experience both drought and deluge (Winter and Rosenberry 1998; Johnson et al 2004). Hydrology research in Prairie wetlands suggests that surrounding land-use changes can significantly affect the water balance due to greater potential evapotranspiration vs. precipitation (Conly and van der Kamp 2001)

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