Microbial processing of plant remains is co‐limited by multiple nutrients in global grasslands

Abstract

Microbial processing of aggregate-unprotected organic matter inputs is key for soil fertility, long-term ecosystem carbon and nutrient sequestration, and a sustainable agriculture. We investigated the effects of adding multiple nutrients (nitrogen, phosphorus, and potassium plus nine essential macro-and micronutrients) on decomposition and biochemical transformation of standard plant materials buried in twenty-one grasslands from four continents. Addition of multiple nutrients weakly but consistently increased decomposition and biochemical transformation of plant remains during the peak-season, concurrent with changes in microbial exoenzymatic activity. Higher mean annual precipitation and lower mean annual temperature were the main climatic drivers of higher decomposition rates, while biochemical transformation of plant remains was negatively related to temperature of the wettest quarter. Nutrients enhanced decomposition most at cool, high rainfall sites, indicating that in a warmer and drier future

Plant genotype controls wetland soil microbial functioning in response to sea-level rise

“…The TBI has widely been applied to characterize and compare decomposition dynamics within and across ecosystems (Keuskamp et al, 2013;Mueller et al, 2018;Ochoa-Hueso et al, 2020). The advantages and limitations of the TBI and other standardized decomposition assays, such as cotton-and cellulose-strip assays, have been extensively discussed elsewhere (Clark, 1970;Mueller et al, 2018;Ochoa-Hueso et al, 2020;Risch et al, 2007). Each pot received, two polypropylene tea bags (55 mm x 50 mm), one containing green tea (EAN: 8 714100 770542; Lipton, Unilever), and one containing rooibos (EAN: 8 722700 188438; Lipton, Unilever).…”

“…The parameters S and k describe the initial transformation process of biomass to soil organic matter, which is a key component of many tidal-wetland resilience models that have highlighted the critical role of the organic contribution to wetland elevation gain (Schile et al, 2014;Swanson et al, 2014). Although actual rates of S and k cannot be inferred from TBI assays using standardized litter, the approach has proven a powerful tool to characterize the potential of the soil environment to transform organic matter inputs (Keuskamp et al, 2013;Mueller et al, 2018;Ochoa-Hueso et al, 2020). Effect sizes of the flooding treatment on S and k observed here are similar in range to those reported from field sites (Tang et al, 2020), and genotype effect sizes were surprisingly large.…”

Plant genotype controls wetland soil microbial functioning in response to sea-level rise

“…We assessed the decomposition of standardized plant litter in the rhizosphere to evaluate if genotype effects on soil microbial exo-enzyme activity translate into altered organic matter turnover and thus into ecosystem functioning (Ochoa-Hueso et al, 2020). The decomposition rate constant (k) and stabilization factor (S) were assessed following the tea bag index (TBI) method (Keuskamp et al, 2013).…”

Comment on bg-2021-41

“…We assessed the decomposition of standardized plant litter in the rhizosphere to evaluate if genotype effects on soil microbial exo-enzyme activity translate into altered organic matter turnover and thus into ecosystem functioning (Ochoa-Hueso et al, 2020). The decomposition rate constant (k) and stabilization factor (S) were assessed following the Tea Bag Index (TBI) https://doi.org/10.5194/bg-2021-41 Preprint.…”