Tree-based intercropping: a land use for greenhouse gas mitigation in canadian agricultural systems

PosterIn tree-based intercropping (TBI) systems, the potential influence of trees in relation to carbon (C ) sequestration and Greenhouse Gas (GHG) emissions reduction has been documented but the mechanisms, remain poorly understood, especially for below-ground processes. Recently, several studies in this area were undertaken in Ontario, Canada under the auspices of Canada’s involvement in the Global Research Alliance. C sequestration potential, nitrous oxide reduction potential and soil voids were quantified in a 25-year-old TBI system in southern Ontario for five tree species: hybrid poplar (Populus spp.), Norway spruce (Picae abies), red oak (Quercus rubra), black walnut (Juglans nigra), and white cedar (Thuja occidentalis) which were intercropped with soybean (Glycine max). Results were compared with a conventional agricultural system in which soybean was grown as the sole crop. The net C flux for poplar, spruce, oak, walnut, cedar and the soybean sole-crop were + 2.1, + 1.6, + 0.8, + 1.8, +1.4 and – 1.2 t C ha-1, y-1, respectively. The results suggest a greater atmospheric CO2 sequestration potential for all five tree species when compared to a conventional agricultural system. DNA was also extracted from soil cores collected around four of the tree species (walnut, red oak, Norway spruce, poplar) and used for quantitative real-time PCR to determine the abundance of key functional genes in the nitrification and denitrification pathways. Results indicate that both tree species and proximity to the tree, can influence the abundance of key microbial groups associated with N2O production, particularly organisms associated with denitrification, nosZ and nirS. Soil void analysis showed that there was a positive correlation between x-ray bulk radio-density and soil bulk density, and a negative correlation between mean intra-aggregate x-ray radio-density and soil organic carbon (rs=-0.48, p=0.033), suggesting that the X-ray CT method could therefore be used to predict these soil properties

Tree-based intercropping: a land use for greenhouse gas mitigation in canadian agricultural systems

PosterIn tree-based intercropping (TBI) systems, the potential influence of trees in relation to carbon (C ) sequestration and Greenhouse Gas (GHG) emissions reduction has been documented but the mechanisms, remain poorly understood, especially for below-ground processes. Recently, several studies in this area were undertaken in Ontario, Canada under the auspices of Canada’s involvement in the Global Research Alliance. C sequestration potential, nitrous oxide reduction potential and soil voids were quantified in a 25-year-old TBI system in southern Ontario for five tree species: hybrid poplar (Populus spp.), Norway spruce (Picae abies), red oak (Quercus rubra), black walnut (Juglans nigra), and white cedar (Thuja occidentalis) which were intercropped with soybean (Glycine max). Results were compared with a conventional agricultural system in which soybean was grown as the sole crop. The net C flux for poplar, spruce, oak, walnut, cedar and the soybean sole-crop were + 2.1, + 1.6, + 0.8, + 1.8, +1.4 and – 1.2 t C ha-1, y-1, respectively. The results suggest a greater atmospheric CO2 sequestration potential for all five tree species when compared to a conventional agricultural system. DNA was also extracted from soil cores collected around four of the tree species (walnut, red oak, Norway spruce, poplar) and used for quantitative real-time PCR to determine the abundance of key functional genes in the nitrification and denitrification pathways. Results indicate that both tree species and proximity to the tree, can influence the abundance of key microbial groups associated with N2O production, particularly organisms associated with denitrification, nosZ and nirS. Soil void analysis showed that there was a positive correlation between x-ray bulk radio-density and soil bulk density, and a negative correlation between mean intra-aggregate x-ray radio-density and soil organic carbon (rs=-0.48, p=0.033), suggesting that the X-ray CT method could therefore be used to predict these soil properties

Tree-based intercropping: a land use for greenhouse gas mitigation in canadian agricultural systems

PosterIn tree-based intercropping (TBI) systems, the potential influence of trees in relation to carbon (C ) sequestration and Greenhouse Gas (GHG) emissions reduction has been documented but the mechanisms, remain poorly understood, especially for below-ground processes. Recently, several studies in this area were undertaken in Ontario, Canada under the auspices of Canada’s involvement in the Global Research Alliance. C sequestration potential, nitrous oxide reduction potential and soil voids were quantified in a 25-year-old TBI system in southern Ontario for five tree species: hybrid poplar (Populus spp.), Norway spruce (Picae abies), red oak (Quercus rubra), black walnut (Juglans nigra), and white cedar (Thuja occidentalis) which were intercropped with soybean (Glycine max). Results were compared with a conventional agricultural system in which soybean was grown as the sole crop. The net C flux for poplar, spruce, oak, walnut, cedar and the soybean sole-crop were + 2.1, + 1.6, + 0.8, + 1.8, +1.4 and – 1.2 t C ha-1, y-1, respectively. The results suggest a greater atmospheric CO2 sequestration potential for all five tree species when compared to a conventional agricultural system. DNA was also extracted from soil cores collected around four of the tree species (walnut, red oak, Norway spruce, poplar) and used for quantitative real-time PCR to determine the abundance of key functional genes in the nitrification and denitrification pathways. Results indicate that both tree species and proximity to the tree, can influence the abundance of key microbial groups associated with N2O production, particularly organisms associated with denitrification, nosZ and nirS. Soil void analysis showed that there was a positive correlation between x-ray bulk radio-density and soil bulk density, and a negative correlation between mean intra-aggregate x-ray radio-density and soil organic carbon (rs=-0.48, p=0.033), suggesting that the X-ray CT method could therefore be used to predict these soil properties

Weak Liouville-Arnold Theorems & Their Implications

This paper studies the existence of invariant smooth Lagrangian graphs for Tonelli Hamiltonian systems with symmetries. In particular, we consider Tonelli Hamiltonians with n independent but not necessarily involutive constants of motion and obtain two theorems reminiscent of the Liouville-Arnold theorem. Moreover, we also obtain results on the structure of the configuration spaces of such systems that are reminiscent of results on the configuration space of completely integrable Tonelli Hamiltonians.Comment: 24 pages, 1 figure; v2 corrects typo in online abstract; v3 includes new title (was: A Weak Liouville-Arnold Theorem), re-arrangement of introduction, re-numbering of main theorems; v4 updates the authors' email and physical addresses, clarifies notation in section 4. Final versio

Ether- and Ester-Bound iso-Diabolic Acid and Other Lipids in Members of <i>Acidobacteria</i> Subdivision 4

Recently, iso-diabolic acid (13,16-dimethyl octacosanedioic acid) has been identified as a major membrane-spanning lipid of subdivisions 1 and 3 of the Acidobacteria, a highly diverse phylum within the Bacteria. This finding pointed to the Acidobacteria as a potential source for the bacterial glycerol dialkyl glycerol tetraethers that occur ubiquitously in peat, soil, lakes, and hot springs. Here, we examined the lipid composition of seven phylogenetically divergent strains of subdivision 4 of the Acidobacteria, a bacterial group that is commonly encountered in soil. Acid hydrolysis of total cell material released iso-diabolic acid derivatives in substantial quantities (11 to 48% of all fatty acids). In contrast to subdivisions 1 and 3 of the Acidobacteria, 6 out of the 7 species of subdivision 4 (excepting “Candidatus Chloracidobacterium thermophilum”) contained iso-diabolic acid ether bound to a glycerol in larger fractional abundance than iso-diabolic acid itself. This is in agreement with the analysis of intact polar lipids (IPLs) by high-performance liquid chromatography-mass spectrometry (HPLC-MS), which showed the dominance of mixed ether-ester glycerides. iso-Diabolic acid-containing IPLs were not identified, because these IPLs are not released with a Bligh-Dyer extraction, as observed before when studying lipid compositions of subdivisions 1 and 3 of the Acidobacteria. The presence of ether bonds in the membrane lipids does not seem to be an adaptation to temperature, because the five mesophilic isolates contained a larger amount of ether lipids than the thermophile “Ca. Chloracidobacterium thermophilum.” Furthermore, experiments with Pyrinomonas methylaliphatogenes did not reveal a major influence of growth temperature over the 50 to 69°C range

Super-A-polynomials for Twist Knots

We conjecture formulae of the colored superpolynomials for a class of twist knots $K_p$ where p denotes the number of full twists. The validity of the formulae is checked by applying differentials and taking special limits. Using the formulae, we compute both the classical and quantum super-A-polynomial for the twist knots with small values of p. The results support the categorified versions of the generalized volume conjecture and the quantum volume conjecture. Furthermore, we obtain the evidence that the Q-deformed A-polynomials can be identified with the augmentation polynomials of knot contact homology in the case of the twist knots.Comment: 22+16 pages, 16 tables and 5 figures; with a Maple program by Xinyu Sun and a Mathematica notebook in the ancillary files linked on the right; v2 change in appendix B, typos corrected and references added; v3 change in section 3.3; v4 corrections in Ooguri-Vafa polynomials and quantum super-A-polynomials for 7_2 and 8_1 are adde

On 3d extensions of AGT relation

An extension of the AGT relation from two to three dimensions begins from connecting the theory on domain wall between some two S-dual SYM models with the 3d Chern-Simons theory. The simplest kind of such a relation would presumably connect traces of the modular kernels in 2d conformal theory with knot invariants. Indeed, the both quantities are very similar, especially if represented as integrals of the products of quantum dilogarithm functions. However, there are also various differences, especially in the "conservation laws" for integration variables, which hold for the monodromy traces, but not for the knot invariants. We also discuss another possibility: interpretation of knot invariants as solutions to the Baxter equations for the relativistic Toda system. This implies another AGT like relation: between 3d Chern-Simons theory and the Nekrasov-Shatashvili limit of the 5d SYM.Comment: 23 page

Pulse‐labeling studies of carbon cycling in Arctic tundra ecosystems: The contribution of photosynthates to methane emission

Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/94952/1/gbc790.pd

Ancestral absence of electron transport chains in Patescibacteria and DPANN

© The Author(s), 2020. This article is distributed under the terms of the Creative Commons Attribution License. The definitive version was published in Beam, J. P., Becraft, E. D., Brown, J. M., Schulz, F., Jarett, J. K., Bezuidt, O., Poulton, N. J., Clark, K., Dunfield, P. F., Ravin, N. V., Spear, J. R., Hedlund, B. P., Kormas, K. A., Sievert, S. M., Elshahed, M. S., Barton, H. A., Stott, M. B., Eisen, J. A., Moser, D. P., Onstott, T. C., Woyke, T., & Stepanauskas, R. Ancestral absence of electron transport chains in Patescibacteria and DPANN. Frontiers in Microbiology, 11, (2020): 1848, doi:10.3389/fmicb.2020.01848.Recent discoveries suggest that the candidate superphyla Patescibacteria and DPANN constitute a large fraction of the phylogenetic diversity of Bacteria and Archaea. Their small genomes and limited coding potential have been hypothesized to be ancestral adaptations to obligate symbiotic lifestyles. To test this hypothesis, we performed cell–cell association, genomic, and phylogenetic analyses on 4,829 individual cells of Bacteria and Archaea from 46 globally distributed surface and subsurface field samples. This confirmed the ubiquity and abundance of Patescibacteria and DPANN in subsurface environments, the small size of their genomes and cells, and the divergence of their gene content from other Bacteria and Archaea. Our analyses suggest that most Patescibacteria and DPANN in the studied subsurface environments do not form specific physical associations with other microorganisms. These data also suggest that their unusual genomic features and prevalent auxotrophies may be a result of ancestral, minimal cellular energy transduction mechanisms that lack respiration, thus relying solely on fermentation for energy conservation.This work was funded by the USA National Science Foundation grants 1441717, 1826734, and 1335810 (to RS); and 1460861 (REU site at Bigelow Laboratory for Ocean Sciences). RS was also supported by the Simons Foundation grant 510023. TW, FS, and JJ were funded by the U.S. Department of Energy Joint Genome Institute, a DOE Office of Science User Facility supported under Contract No. DE-AC02-05CH11231. NR group was funded by the Russian Science Foundation (grant 19-14-00245). SS was funded by USA National Science Foundation grants OCE-0452333 and OCE-1136727. BH was funded by NASA Exobiology grant 80NSSC17K0548