Comparison of Compaction Alleviation Methods on Soil Health and Greenhouse Gas Emissions

Soil compaction can occur due to trafficking by heavy equipment and be exacerbated by unfavourable conditions such as wet weather. Compaction can restrict crop growth and increase waterlogging, which can increase the production of the greenhouse gas nitrous oxide. Cultivation can be used to alleviate compaction, but this can have negative impacts on earthworm abundance and increase the production of the greenhouse gas carbon dioxide. In this study, a field was purposefully compacted using trafficking, then in a replicated plot experiment, ploughing, low disturbance subsoiling and the application of a mycorrhizal inoculant were compared as methods of compaction alleviation, over two years of cropping. These methods were compared in terms of bulk density, penetration resistance, crop yield, greenhouse gas emissions and earthworm abundance. Ploughing alleviated topsoil compaction, as measured by bulk density and penetrometer resistance, and increased the crop biomass in one year of the study, although no yield differences were seen. Earthworm abundance was reduced in both years in the cultivated plots, and carbon dioxide flux increased significantly, although this was not significant in summer months. Outside of the summer months, nitrous oxide production increased in the non-cultivated treatments, which was attributed to increased denitrifying activity under compacted conditions.

Denitrication and N₂O production in Canadian Lakes: effects of nutrient ratios acting through primary producer selection

Anthropogenic nutrient loading to aquatic systems may increase atmospheric release of nitrous oxide (N₂O) greenhouse gas by enhancing denitrification and/or nitrification. High Si:N loading may favour diatom abundance, whereas low N:P loading may favour cyanobacteria dominance. Systems with diatom or green algal dominance may have greater export of organic matter to sediments, whereas systems dominated by cyanobacteria may have organic matter recycled within the water column due to differences in cell density and sinking. With increased export of organic matter to sediments, denitrification and N₂O production may be stimulated. In laboratory bench-scale microcosms, nitrous oxide production was affected by Si:N loading ratios as predicted, although N:P loading did not affect N₂O production in the manner predicted. However, the predicted effects of nutrient loading ratio on microphyte community composition were not supported by microscopy. Field mesocosm experiments indicated no significant relationship between N₂O production and nutrient loading ratios.

Denitrication and N₂O production in Canadian Lakes: effects of nutrient ratios acting through primary producer selection

Anthropogenic nutrient loading to aquatic systems may increase atmospheric release of nitrous oxide (N₂O) greenhouse gas by enhancing denitrification and/or nitrification. High Si:N loading may favour diatom abundance, whereas low N:P loading may favour cyanobacteria dominance. Systems with diatom or green algal dominance may have greater export of organic matter to sediments, whereas systems dominated by cyanobacteria may have organic matter recycled within the water column due to differences in cell density and sinking. With increased export of organic matter to sediments, denitrification and N₂O production may be stimulated. In laboratory bench-scale microcosms, nitrous oxide production was affected by Si:N loading ratios as predicted, although N:P loading did not affect N₂O production in the manner predicted. However, the predicted effects of nutrient loading ratio on microphyte community composition were not supported by microscopy. Field mesocosm experiments indicated no significant relationship between N₂O production and nutrient loading ratios.

Cardamonin Attenuates Experimental Colitis and Associated Colorectal Cancer

Cardamonin is a naturally occurring chalcone, majorly from the Zingiberaceae family, which includes a wide range of spices from India. Herein, we investigated the anti-inflammatory property of cardamonin using different in vitro and in vivo systems. In RAW 264.7 cells, treatment with cardamonin showed a reduced nitrous oxide production without affecting the cell viability and decreased the expression of iNOS, TNF-α, and IL-6, and inhibited NF-kB signaling which emphasizes the role of cardamonin as an anti-inflammatory molecule. In a mouse model of dextran sodium sulfate (DSS)-induced colitis, cardamonin treatment protected the mice from colitis. Subsequently, we evaluated the therapeutic potential of this chalcone in a colitis-associated colon cancer model. We performed microRNA profiling in the different groups and observed that cardamonin modulates miRNA expression, thereby inhibiting tumor formation. Together, our findings indicate that cardamonin has the potential to be considered for future therapy against colorectal cancer.

Biological Nitrate Removal With Emerald Ash Borer-Killed Ash and High-Tannin Oak Woodchips

Two common tree species, ash (Fraxinus sp.) and oak (Quercus sp.), could provide readily available media for denitrifying bioreactors that use wood-based carbon for biological nitrate treatment. However, it is not known if the wood from Emerald Ash Borer-killed (EAB-killed) ash trees is an effective carbon source for nitrate removal compared to other wood species or if the high-tannin nature of oak inhibits denitrification potential. This lab-scale study showed that EAB-killed ash woodchips did not significantly differ in nitrate removal or denitrification potential compared to a commercially available blend of hardwood chips. However, neither treatment performed as well as oak woodchips in these metrics. Use of high-tannin oak in bioreactors is currently restricted by a federal standard in the United States. Ash woodchips beneficially exhibited the lowest nitrous oxide production potential, and their dissolved phosphorus leaching fell within the range of other woodchip types. Emerald ash borer-killed ash wood could be an effective source for denitrifying bioreactors located within affected regions and oak woodchips merit additional investigation for the application of denitrifying bioreactors.