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2014

NEW PAPER: Dynamic Soil Property Change in Response to Reclamation following Northern Appalachian Natural Gas Infrastructure Development
December 16, 2014
How do soils differ in the Northern Appalachians following conventional versus reclaimed shale-gas development? In this new paper published in the Soil Science Society of America Journal we examine physical, chemical and hydrologic changes on gas pads and pipelines that were part of the 1900's and 1970's gas booms, and the current shale-gas boom. Our results show that conventional sites do not exhibit significant differences in dynamic soil properties between disturbed and undisturbed soils while shale-gas sites show significantly higher (potentially root limiting) bulk density and lower SOC and N pools on reclaimed, disturbed soils.
Could vacant lots double as green infrastructure projects?
April 15, 2014
"The idea of using green infrastructure, from rain gardens and rain buckets to porous streets and simple sidewalk grass and plantings, is among the few environmental solutions that exists virtually unopposed. Big, old cities in the U.S. tend to have outdated sewer systems that overflow when it rains a lot, thanks to the built environment’s inability to slow all that water down."
NEW PAPER: Residential demolition and its impact on vacant lot hydrology: Implications for the management of stormwater and sewer system overflows
March 28, 2014
W.D. Shuster, S. Dadio, P. Drohan, R. Losco, J. Shaffer. Increased residential demolitions have made vacant lots a ubiquitous feature of the contemporary urban landscape. Vacant lots may provide ecosystem services such as stormwater runoff capture, but the extent of these functions will be regulated by soil hydrology. We evaluated soil physical and hydrologic characteristics at each of low- (backyard, fenceline) and high-disturbance (within the demolition footprint) positions in 52 vacant lots in Cleveland, OH, which were the result of different eras of demolition process and quality (i.e., pre-1996, post-1996). Penetrometer refusal averaged 56% (range: 15–100%) and was attributed to high concentration of remnant buried debris in anthropogenic backfill soils. Both disturbance level and demolition type significantly regulated infiltration rate to an average of 1.8 cm h−1 (range: 0.03–10.6 cm h−1). Sub-surface saturated hydraulic conductivity (Ksat) averaged higher at 4.0 cm h−1 (range: 0–68.2 cm h−1), was influenced by a significant interaction between both disturbance and demolition factors, and controlled by subsurface soil texture and presence/absence of unconsolidated buried debris. Our observations were synthesized in rainfall-runoff models that simulated average, high- and low-hydrologic functioning, turf-dominated, and a prospective green infrastructure simulation, which indicated that although the typical Cleveland vacant lot is a net producer of runoff volume, straightforward change in demolition policy and process, coupled with reutilization as properly designed and managed infiltration-type green infrastructure may result in a vacant lot that has sufficient capacity for detention of the average annual rainfall volume for a major Midwestern US city.
NEW PAPER: Turnover of soil carbon following addition of switchgrass-derived biochar to four soils
January 17, 2014
Binh T. Nguyen, Roger T. Koide, Curtis Dell*, Patrick Drohan, Howard Skinner, Paul R. Adler, and Andrea Nord. Amending soils with biochar can sequester C and improve soil properties, such as nutrient holding capacity and water retention. While biochars generally have a long residence time in soil, the turnover of biochar-C can be influenced by both biochar characteristics and soil properties. Biochar can also potentially alter the rate of decomposition of native soil organic matter (SOM). The turnover of switchgrass-derived biochar-C was evaluated in the laboratory using soil from four marginally productive sites in central Pennsylvania. Carbon dioxide emissions from unamended soil, biochar-amended soil, and pure biochar were monitored during 189 day incubations, and data was fit to a two-pool exponential model to estimate the amount and mean residence time (MRT) of C in labile and stable pools. Carbon-13 signatures of emitted CO2 were also determined to estimate the proportion of emitted CO2 derived from the biochar. Mixing biochar with each of the soils reduced the apparent MRT of C in both labile and stable pools, but the magnitude of change depended on the soil. Overall the biochar was largely stable in each soil, with only 1.1 to 2.1 % of the added biochar-C emitted during incubation. There was no measurable effect of biochar amendment on turnover of native SOM in any of the soils. Therefore, we conclude that amendment of our soils with switchgrass-derived biochar can effectively increase net C sequestration.