Chronic nitrogen fertilization and carbon sequestration in grassland soils: evidence of a microbial enzyme link

Cenini, Valeria L.; Fornara, Dario; McMullan, Geoffrey; Ternan, Nigel G.; Lajtha, Kate; Crawley, Michael J.

doi:10.1007/s10533-015-0157-5

Cited by 79 publications

(33 citation statements)

References 55 publications

Supporting

Mentioning

Contrasting

Unclassified

Order By: Relevance

“…Our results are also similar to those from a 19‐yr grassland fertilization experiment that found that N significantly increased C‐degrading enzyme activities in low pH soils with wide C:N plant inputs but increases were less pronounced in limed soils with narrow C:N plant inputs (Cenini et al. ). Together, these findings suggest that microbes in the high C:N soils, represented here by ECM plots, can respond directly to increased N availability by producing more C‐degrading enzymes relative to N‐degrading enzymes.…”

Section: Discussionsupporting

confidence: 90%

Resource stoichiometry and the biogeochemical consequences of nitrogen deposition in a mixed deciduous forest

Midgley

Phillips

2016

Ecology

View full text Add to dashboard Cite

Ecosystems often show differential sensitivity to chronic nitrogen (N) deposition; hence, a critical challenge is to improve our understanding of how and why site-specific factors mediate biogeochemical responses to N enrichment. We examined the extent to which N impacts on soil carbon (C) and N dynamics depend on microbial resource stoichiometry. We added N to forest plots dominated by ectomycorrhizal (ECM) trees, which have litter and soil pools rich in organic N and relatively wide C:N ratios, and adjacent forest plots dominated by arbuscular mycorrhizal (AM) trees, which have litter and soil pools rich in inorganic N and relatively narrow C:N ratios. While microbes in both plot types exhibited fairly strict biomass homeostasis, microbes in AM- and ECM-dominated plots differed in their physiological responses to N addition. Microbes in ECM plots responded to N enrichment by decreasing their investment in N-acquisition enzymes (relative to C-acquisition enzymes) and increasing N mineralization rates (relative to C mineralization rates), suggesting that N addition alleviated microbial N demand. In contrast, heterotrophic microbial activities in AM plots were unaffected by N addition, most likely as a result of N-induced increases in net nitrification (60% increase relative to control plots) and nitrate mobilization (e.g., sixfold increases in mobilization relative to control plots). Combined, our findings suggest the stoichiometric differences between AM and ECM soils are the primary drivers of the observed responses. Plant and microbial communities characterized by wide C:N are more susceptible to N-induced changes in decomposition and soil C dynamics, whereas communities characterized by narrow C:N are more susceptible to N-induced nitrate leaching losses. Hence, the biogeochemical consequences of N deposition in temperate forests may be driven by the stoichiometry of the dominant trees and their associated microbes.

show abstract

Section: Discussionsupporting

confidence: 90%

Resource stoichiometry and the biogeochemical consequences of nitrogen deposition in a mixed deciduous forest

Midgley

Phillips

2016

Ecology

View full text Add to dashboard Cite

show abstract

“…For example, Cenini et al. () show how an increase in microbial energy demand (i.e., C demand) as a result of low C:N plant detritus inputs in the same fertilized grasslands will increase the activity of the C‐acquiring enzyme β‐1,4‐glucosidase. The increased activity of this enzyme was then linked to more C being processed and accumulated (including microbial biomass C) into organo‐mineral soil pools.…”

Section: Discussionmentioning

confidence: 99%

“…, Cenini et al. ). Key knowledge gaps remain about how long‐term grassland management might influence plant tissue chemistry, and whether or not changes in plant element stoichiometry (e.g., C:N:P ratios) might be related to predictable changes in soil C, N, and P content (%) and storage (i.e., soil C, N, and P pools).…”

Section: Introductionmentioning

confidence: 99%

Effects of grassland management on plant C:N:P stoichiometry: implications for soil element cycling and storage

et al. 2017

Self Cite

View full text Add to dashboard Cite

Abstract. The functioning of human-managed grassland ecosystems strongly depends on how common management practices (e.g., animal grazing and the chronic addition of fertilizing materials to soils) interact to influence plant and soil element stoichiometry. Here we use data from a 22-yr-long grassland experiment to address whether and how plant element stoichiometry (i.e., carbon [C], nitrogen [N], phosphorus [P] ratios) might respond to (1) animal grazing, (2) agricultural liming (i.e., CaCO 3 ) applications, and (3) nutrient fertilization. We also ask whether plant C:N:P stoichiometry could predict changes in soil N and P availability and in soil C, N, and P stocks. We found that grassland management significantly affected plant C:N:P ratios as predicted by ecological stoichiometry theory. For example, plant aboveground and belowground C:N and C:P ratios decreased under chronic N and P fertilization, respectively. Plant C:N and C:P ratios were significantly greater in unfertilized (control) soils. Also plant C:N ratios were highest under P-only additions, whereas plant C:P ratios were highest under N-only additions. However, unpredictable changes in C:N:P ratios also occurred, suggesting that plant tissue chemistry may not be a simple reflection of soil nutrient availability. Changes in plant C:nutrient ratios well predicted variation in soil nutrient availability, but not in soil C, N, and P stocks. Contrary to expectations, soil C stocks significantly increased with decreasing plant C:N ratios in the nutrient-fertilized grasslands and not with increasing plant C:N ratios in the unfertilized grasslands. We suggest that a better mechanistic understanding of the negative relationship between plant C:N stoichiometry and soil C accrual will greatly help in improving the sustainability of human-managed grasslands.

show abstract

“…A recent study shows, for example, how the addition of plant biomass to soils from different cover crops is positively related to both BG activity and soil C sequestration (Peregrina et al, 2014). Once BG has been produced and released into the soil, it could potentially be disabled through binding to mineral and organic colloids (Allison and Jastrow, 2006) thus contributing (together with other microbial 'waste' products) to the accumulation of C in soils (Cotrufo et al, 2013;Cenini et al, 2015).…”

Section: Tablementioning

confidence: 99%

Linkages between extracellular enzyme activities and the carbon and nitrogen content of grassland soils

Cenini

Fornara

McMullan

et al. 2016

Soil Biology and Biochemistry

Self Cite

192

View full text Add to dashboard Cite

Important biochemical reactions in soils are catalyzed by extracellular enzymes, which are synthesized by microbes and plant roots. Although enzyme activities can significantly affect the decomposition of soil organic matter and thus influence the storage and cycling of carbon (C) and nitrogen (N), it is not clear how enzyme activities relate to changes in the C and N content of different grassland soils. Here we address whether the activity of C-acquiring (b-1,4-glucosidase, BG) and N-acquiring (L-leucine aminopeptidase (LAP) and b-1,4-N-acetyl-glucosaminidase (NAG)) enzymes is linked to changes in the C and N content of a variety of human-managed grassland soils. We selected soils which have a well-documented management history going back at least 19 years in relation to changes in land use (grazing, mowing, ploughing), nutrient fertilization and lime (CaCO 3) applications. Overall we found a positive relationship between BG activity and soil C content as well as between LAP þ NAG activity and soil N. These positive relationships occurred across grasslands with very different soil pH and management history but not in intensively managed grasslands where increases in soil bulk density (i.e. high soil compaction) negatively affected enzyme activity. We also found evidence that chronic nutrient fertilization contributed to increases in soil C content and this was associated with a significant increase in BG activity when compared to unfertilized soils. Our study suggests that while the activities of C-and N-acquiring soil enzymes are positively related to soil C and N content, these activities respond significantly to changes in management (i.e. soil compaction and nutrient fertilization). In particular, the link between BG activity and the C content of long-term fertilized soils deserves further investigation if we wish to improve our understanding of the C sequestration potential of human-managed grassland soils.

show abstract

Chronic nitrogen fertilization and carbon sequestration in grassland soils: evidence of a microbial enzyme link

Cited by 79 publications

References 55 publications

Resource stoichiometry and the biogeochemical consequences of nitrogen deposition in a mixed deciduous forest

Resource stoichiometry and the biogeochemical consequences of nitrogen deposition in a mixed deciduous forest

Effects of grassland management on plant C:N:P stoichiometry: implications for soil element cycling and storage

Linkages between extracellular enzyme activities and the carbon and nitrogen content of grassland soils

Contact Info

Product

Resources

About