Evaluating Management Options to Increase Roadside Carbon Sequestration

We estimated the amount of carbon sequestered along Montana Department of Transportation (MDT) roads and tested 3 different highway right-of-way (ROW) management techniques to increase carbon stocks. Using Geographic Information System techniques, the total ROW acreage owned by MDT was found to sequester 75,292 metric tons of carbon per year and to consist mostly of grasslands (70%). From 2016-2018 we tested 3 ROW management techniques to increase carbon stocks- increase mowing height, plant woody shrubs, or add legumes to reclamation seed mixes of disturbed soils - at 3 sites (Three Forks [3F], Bear Canyon [BC], and Bozeman Pass [BP]) along Interstate 90 in southwestern Montana. Soil samples generally averaged 0.75–1.5% soil organic carbon (SOC) at the 3F site, 2.5–4% SOC at the BC site, and 1.5–2.5% SOC at the BP site. Average SOC levels were always lower in 2018 than in 2016. Soil respiration rates were generally highest in June or July at the BC site, averaging ~4 μmol CO2 m-2 second-1. Soil respiration rates were lower at the BC site in November 2016, at the BP site in June 2018, and at the 3F site in July 2018 (all ~2–3 μmol CO2 m-2 s-1). Aboveground biomass carbon estimates generally mirrored belowground SOC estimates. Taken together, our findings suggest that of the three treatments implemented (raised mowing height, shrub planting, and disturbance), minimizing disturbance to soils likely makes the greatest contribution to the medium- and long-term carbon-storage potential of these roadside soils

Estimating the uncertainty of areal precipitation using data assimilation

We present a method to estimate spatially and temporally variable uncertainty of areal precipitation data. The aim of the method is to merge measurements from different sources, remote sensing and in situ, into a combined precipitation product and to provide an associated dynamic uncertainty estimate. This estimate should provide an accurate representation of uncertainty both in time and space, an adjustment to additional observations merged into the product through data assimilation, and flow dependency. Such a detailed uncertainty description is important for example to generate precipitation ensembles for probabilistic hydrological modelling or to specify accurate error covariances when using precipitation observations for data assimilation into numerical weather prediction models. The presented method uses the Local Ensemble Transform Kalman Filter and an ensemble nowcasting model. The model provides information about the precipitation displacement over time and is continuously updated by assimilation of observations. In this way, the precipitation product and its uncertainty estimate provided by the nowcasting ensemble evolve consistently in time and become flow-dependent. The method is evaluated in a proof of concept study focusing on weather radar data of four precipitation events. The study demonstrates that the dynamic areal uncertainty estimate outperforms a constant benchmark uncertainty value in all cases for one of the evaluated scores, and in half the number of cases for the other score. Thus, the flow dependency introduced by the coupling of data assimilation and nowcasting enables a more accurate spatial and temporal distribution of uncertainty. The mixed results achieved in the second score point out the importance of a good probabilistic nowcasting scheme for the performance of the method

Evaluation of Effectiveness and Cost-Benefits of Woolen Roadside Reclamation Products

This research project developed three types of products for study: woolen erosion control blankets (ECBs), wool incorporated into wood fiber compost at a 40:1 ratio (compost to wool, by weight), and wool incorporated into silt fence. The project, supported by Montana Department of Transportation (MDT) and the Center for Environmentally Sustainable Transportation in Cold Climates, compared the wool products’ performance to roadside reclamation products commonly used for revegetating cut slopes: straw/coconut (coir) ECB, wood fiber compost and woven plastic silt fence. Three versions of wool silt fence were developed by the project, yet, even more versions are needed to arrive at a commercially viable product. Wool silt fence was the least promising of the three types of reclamation materials. The primary measure for success for ECBs and wool additive to the compost was the amount of seeded or desired vegetation they established after two growing seasons. The research team evaluated the performance of the woolen and standard products by measuring the percentage of canopy cover of each plant species present in each treatment plot. Canopy cover measures the percentage of ground that is covered by a vertical projection of a plant’s foliage. To conduct the comparative analysis, researchers calculated an average percent canopy cover for each functional group: seeded native grasses, desired non-seeded (volunteer) grasses and forbs, and weeds. There was no statistical difference in the mean canopy cover of seeded grass species of the compost treatment (control) compared to the cut wool with compost treatment, 6.4% and 10.2%, respectively. Thus, the project could not determine that cut wool pieces provided a benefit to plant establishment and growth when it is added to compost material. Further experimentation to determine the ideal ratio of wool pieces to add to compost is warranted. The two best performing treatments (i.e. greatest seeded grass establishment) were the rolled wool/straw ECBs. The 100% wool ECB and 50% wool/50% straw ECB had the greatest mean seeded grass canopy cover after two years. Both of these wool ECBs had more seeded grass canopy cover than the standard 70% straw/30% coir ECB demonstrating their potential as a commercially viable product for roadside revegetation applications. Laboratory tests of the wool/straw ECB demonstrated it was comparable to the specifications of a short-term (Type II B or C) standard ECB used along MDT roadways. Future product development of the wool/straw ECB should focus on improving the shear strength at high flows so it meets all required Type III specifications

Deterministic quantum state transfer from an electronic charge qubit to a photonic polarization qubit

Building on an earlier proposal for the production of polarization-entangled microwaves by means of intraband transitions in a pair of quantum dots, we show how this device can be used to transfer an unknown single-qubit state from electronic charge to photonic polarization degrees of freedom. No postselection is required, meaning that the quantum state transfer happens deterministically. Decoherence of the charge qubit causes a non-monotonic decay of the fidelity of the transferred state with increasing decoherence rate.Comment: 3 pages, 3 figure

Evaluating the Potential Effects of Deicing Salts on Roadside Carbon Sequestration

This project sought to document patterns of road deicing salts and the effects of these salts on the amount of carbon being sequestered passively along Montana Department of Transportation roads; it was designed collaboratively with a related roadside project that tested three different highway right-of-way management techniques (mowing height, shrub planting, disturbance) to determine whether they have the capacity to increase soil organic carbon. Our sampling did not reveal elevated salt levels at any of the nine locations sampled at each of the three I-90 sites. The greatest saline concentrations were found at the sample locations farthest from the road. This pattern was consistent across all three sites. The range of soil organic matter (SOM) was broad, from ~1% to >10%. Generally, SOM values were lowest adjacent to the road and highest farthest from the road. We found no or weak evidence of a relationship between our indices of soil salinity and SOM levels, with electrical conductivity, exchangeable calcium, and cation exchange capacity. Results imply that if road deicing salts are altering patterns of roadside SOM and potential carbon sequestration, this effect was not captured by our experimental design, nor did deicing salts appear to have affected roadside vegetation during our most recent sampling effort. Our findings highlight the value of experimentally separating the multiple potentially confounding effects of winter maintenance operations on roadside soils: roads could focus the flow of water, salts, and sands to roadside soils. How these types of mass inputs to roadside soils might influence medium- or long-term carbon dynamics remains an open question, but their fuller characterization and possible flow paths will be essential to clarifying the role of roadside soils in terrestrial soil organic carbon sequestration strategies