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Updates from the Turf Farm: Soil C quality and soil respiration rates Paul J. Lilly, Jennifer C. Jenkins The Rubenstein School of Environment and Natural.

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Presentation on theme: "Updates from the Turf Farm: Soil C quality and soil respiration rates Paul J. Lilly, Jennifer C. Jenkins The Rubenstein School of Environment and Natural."— Presentation transcript:

1 Updates from the Turf Farm: Soil C quality and soil respiration rates Paul J. Lilly, Jennifer C. Jenkins The Rubenstein School of Environment and Natural Resources, University of Vermont BES Annual Meeting 16 October, 2008

2 The Residential Carbon Project - Soil type - Previous land use - Vegetation density - Structure density - Age of housing - Management??

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5 What do we know about management? - Everybody mows - Mowing heights between 5 and 15cm (Residential Carbon Project sites) - Lots of people fertilize - 70% in Glyndon, 50% in Baisman Run (Law et al. 2004) - self-application ~100 kgN/ha/yr, range ~ ; lawn services ~ kgN/ha/yr (Law et al. 2004); UMD extension says kgN/ha/yr - Some people water -~60% of residential water use is outdoor (Mayer et al. 1999) -~10% of households in Law et al. survey -~55% of households in Syracuse, NY survey (Lilly unpublished) - Everything else is minor

6 40 ft. 5 ft. Rep 3 Rep 1 Rep 2

7 40 ft. 5 ft. Rep 3 Rep 1 Rep 2

8 40 ft. 5 ft. Rep 3 Rep 1 Rep 2

9 40 ft. N1 N2 N0 N1 N2 N0 N2 N1 N2 N0 N2 N1 N0 N2 N0 N2 N1 N0 N1 N0 N2 N0 N2 N1 N0 N2 N1 N2 N0 5 ft. Rep 3 Rep 1 Rep 2

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11 Belowground respiration (soil only collar) aboveground respiration = respiration on (soil + veg) collar – respiration on (soil only) collar C uptake = Δ standing stock C + Δ total soil C + Clippings C + Δ Microbial biomass C + (Soil + veg) respiration + DOC export C Cycling at the Turf Farm Total soil C DOC export in soil water Aboveground (stubble/thatch) C Belowground (root) C Root turnover Clippings C Fast pool Passive pool = Total soil C – (fast pool+slow pool) Slow pool Potential C min Microbial Biomass C Standing Biomass C

12 - Labile C pool changes seasonally - Net gain over the last year C mineralization (OM to CO 2 )

13 Belowground respiration (soil only collar) aboveground respiration = respiration on (soil + veg) collar – respiration on (soil only) collar C uptake = Δ standing stock C + Δ total soil C + Clippings C + Δ Microbial biomass C + (Soil + veg) respiration + DOC export C Cycling at the Turf Farm Total soil C DOC export in soil water Aboveground (stubble/thatch) C Belowground (root) C Root turnover Clippings C Fast pool Passive pool = Total soil C – (fast pool+slow pool) Slow pool Potential C min Microbial Biomass C Standing Biomass C

14 Fast and slow(er) soil C

15 Belowground respiration (soil only collar) aboveground respiration = respiration on (soil + veg) collar – respiration on (soil only) collar C uptake = Δ standing stock C + Δ total soil C + Clippings C + Δ Microbial biomass C + (Soil + veg) respiration + DOC export C Cycling at the Turf Farm Total soil C DOC export in soil water Aboveground (stubble/thatch) C Belowground (root) C Root turnover Clippings C Fast pool Passive pool = Total soil C – (fast pool+slow pool) Slow pool Potential C min Microbial Biomass C Standing Biomass C

16 Clippings Production -Mowing matters!

17 Belowground respiration (soil only collar) aboveground respiration = respiration on (soil + veg) collar – respiration on (soil only) collar C uptake = Δ standing stock C + Δ total soil C + Clippings C + Δ Microbial biomass C + (Soil + veg) respiration + DOC export C Cycling at the Turf Farm Total soil C DOC export in soil water Aboveground (stubble/thatch) C Belowground (root) C Root turnover Clippings C Fast pool Passive pool = Total soil C – (fast pool+slow pool) Slow pool Potential C min Microbial Biomass C Standing Biomass C

18 Soil (and plant) respiration Oct ‘07 Sept ‘08

19 To sum up: - For clippings, mowing matters most, then fertilizing; watering doesn’t. -Labile C pool indicator changes (a lot) seasonally; not related to treatments; some indication pool might be increasing under most treatments - Microbial biomass doesn’t change seasonally; no obvious treatment effects -Control of respiration is dominated by watering; in a wet year like this year, treatment differences are swamped - Some indication soil C quality (lability) may be changing

20 Acknowledgements -Jen Jenkins, Peter Groffman -Mark Carroll, Dave, Matt, Joe -Gio McClenachan -Dan Dillon -Lisa Martel and David Lewis -NSF -UMBC and CUERE


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