The detrital input and removal treatment (DIRT) network: Insights into soil carbon stabilization
| Autor: | Kate Lajtha, István Fekete, Richard D. Bowden, Myrna J. Simpson, Zsolt Kotroczó, Susan E. Crow, Knute J. Nadelhoffer, Alain F. Plante |
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| Rok vydání: | 2018 |
| Předmět: |
2. Zero hunger
Environmental Engineering 010504 meteorology & atmospheric sciences Soil organic matter Soil chemistry Soil classification Edaphic 04 agricultural and veterinary sciences Soil carbon 15. Life on land Plant litter 01 natural sciences Pollution Soil respiration Agronomy 040103 agronomy & agriculture 0401 agriculture forestry and fisheries Environmental Chemistry Environmental science Soil fertility Waste Management and Disposal 0105 earth and related environmental sciences |
| Zdroj: | Science of The Total Environment. :1112-1120 |
| ISSN: | 0048-9697 |
| Popis: | Ecological research networks functioning across climatic and edaphic gradients are critical for improving predictive understanding of biogeochemical cycles at local through global scales. One international network, the Detrital Input and Removal Treatment (DIRT) Project, was established to assess how rates and sources of plant litter inputs influence accumulations or losses of organic matter in forest soils. DIRT employs chronic additions and exclusions of aboveground litter inputs and exclusion of root ingrowth to permanent plots at eight forested and two shrub/grass sites to investigate how soil organic matter (SOM) dynamics are influenced by plant detrital inputs across ecosystem and soil types. Across the DIRT network described here, SOM pools responded only slightly, or not at all, to chronic doubling of aboveground litter inputs. Explanations for the slow or even negative response of SOM to litter additions include increased decomposition of new inputs and priming of old SOM. Evidence of priming includes increased soil respiration in litter addition plots, decreased dissolved organic carbon (DOC) output from increased microbial activity, and biochemical markers in soil indicating enhanced SOM degradation. SOM pools decreased in response to chronic exclusion of aboveground litter, which had a greater effect on soil C than did excluding roots, providing evidence that root-derived C is not more critical than aboveground litter C to soil C sequestration. Partitioning of belowground contributions to total soil respiration were predictable based on site-level soil C and N as estimates of site fertility; contributions to soil respiration from root respiration were negatively related to soil fertility and inversely, contributions from decomposing aboveground litter in soil were positively related to site fertility. The commonality of approaches and manipulations across the DIRT network has provided greater insights into soil C cycling than could have been revealed at a single site. |
| Databáze: | OpenAIRE |
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