Castanha et al. 2018: Hopland Lysimeter 13C-Labeled Root Litter Decomposition Study.

Dataset · Fri Dec 31 23:00:00 EST 2021

DOI:https://doi.org/10.15485/1895464· OSTI ID:1895464

Castanha, Cristina ^[1]; Zhu, Biao ^[2]; Hicks Pries, Caitlin ^[3]; Georgiou, Katerina ^[4]; Torn, Margaret ^[5]

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1. Lawrence Berkeley National Laboratory; Lawrence Berkeley National Laboratory
2. Peking University
3. Dartmouth College
4. Lawrence Livermore National Laboratory
5. Lawrence Berkeley National Laboratory

The breakdown and decomposition of plant inputs are critical for nutrient cycling, soil development, and climate-ecosystem feedbacks, but uncertainties persist in how the rates and products of litter decomposition are affected by soil temperature, rhizosphere, and depth of input. To elucidate these questions we measured the effects of soil warming (+ 4 °C), rhizosphere, and depth of litter placement on the decomposition of Avena fatua (wild oat grass) root litter in a Mediterranean grassland ecosystem. Field lysimeters were subjected to three environmental treatments (heating, control, and plant removal) and three 13C-labeled root litter addition treatments (to A horizon, to B horizon, and no-addition disturbance control) for each of two harvest time points. We buried root litter in February 2014 and measured loss of 13C in CO2 from the soil surface and in leachate as dissolved organic carbon (DOC) over two growing seasons. At the end of each of the 2014 and 2015 growing seasons we recovered the 13C remaining in the soil. Loss of root litter C occurred almost entirely via heterotrophic respiration, with an estimated < 2% lost as DOC during the initial decay period. The added roots were broken down and incorporated into bulk soil material very quickly; only ~ 30% of added root was visible after 6 months. In the first growing season, decomposition occurred faster in the B than in the A horizon, the latter having greater moisture limitation. Subsequently, there was almost no further decomposition in the B horizon. After two growing seasons, less than 20% of the added root litter C remained in the A or B horizons of all environmental treatments. Heating did not stimulate decomposition, likely because it exacerbated the moisture limitation. However, while plots without plants dried down more slowly than plots with plants, their decomposition rate was not significantly greater, possibly due to the lack of rhizosphere processes such as priming. We conclude that in this Mediterranean grassland ecosystem, soil moisture, which is affected by season, depth, heating, and rhizosphere, plays a dominant role in mediating the effect of those factors on root litter decomposition, which after two seasons did not differ by depth or by treatment.The files in this dataset comprise (1) 13C-labeled litter additions made to each plot, (2) litter recovery after each of 2 growing seasons, (3) periodical soil flux measurements, (4) leachate measurements, and continuously monitored soil (5) temperature and (6) moisture.

• Research Organization: Environmental System Science Data Infrastructure for a Virtual Ecosystem; Belowground Biogeochemistry Scientific Focus Area
• Sponsoring Organization: U.S. DOE > Office of Science > Biological and Environmental Research (BER)
• OSTI ID: 1895464
• Country of Publication: United States
• Language: English

Related Subjects

54 ENVIRONMENTAL SCIENCES
EARTH SCIENCE &gt; LAND SURFACE &gt; SOILS
EARTH SCIENCE &gt; LAND SURFACE &gt; SOILS &gt; CARBON
EARTH SCIENCE &gt; LAND SURFACE &gt; SOILS &gt; NITROGEN
EARTH SCIENCE &gt; LAND SURFACE &gt; SOILS &gt; SOIL MOISTURE/WATER CONTENT
EARTH SCIENCE &gt; LAND SURFACE &gt; SOILS &gt; SOIL RESPIRATION
EARTH SCIENCE &gt; LAND SURFACE &gt; SOILS &gt; SOIL TEMPERATURE