The development of soil structure, characterized by fractal geometry, improves plant-rooting development and improves water retention, drainage, and air permeability. However, due to this function to increase fertility, excessive intensive cultivation contributes to environmental load. The amount of nitrogen in rivers in agricultural watersheds is significantly related to the surplus nitrogen in the watershed, and since the nitrogen load increases with the increase in the crop field proportion, it is important to manage the surplus nitrogen in crop field. On the other hand, since wetlands have reduced the surplus nitrogen in the watershed through the purification of nitrate nitrogen in river water, it is possible to reduce the environmental load by optimizing land use. Replacing a part of chemical fertilizer application with organic fertilizer application increased soil organic carbon and contribute to the prevention of global warming without reducing crop yield. In Japanese grasslands, the annual application of 3.5tC ha-1 of compost offset greenhouse gas emissions. Furthermore, the continuous use of compost mitigated soil acidification and suppressed N2O emissions. I investigated the impact of greenhouse gas emissions associated with agricultural development on permafrost and peat soils, which are the world's soil carbon reservoirs. In eastern Siberia, disturbance of taiga forests caused permafrost melting and increased CH4 emissions. Drainage of peatland reduced CH4 emissions, but increased CO2 and N2O emissions due to peat decomposition, which was exacerbated by the application of chemical fertilizers. It was essential to keep the groundwater level at -20 cm to -40 cm to suppress greenhouse gas emissions. Environmental load means that soil health is being damaged. It is necessary to develop agricultural techniques to maintain and restore soil health. In particular, organic matter management can restore soil structure by increasing soil organic matter, and also reduce the amount of chemical fertilizer used, which has the effect of reducing greenhouse gas emissions. On the other hand, excessive continuous use of organic fertilizer can increase nitrogen loads. It has been pointed out that the relationship between cover crops and tillage is also important for organic matter management. Regional research is increasingly essential.

Permafrost regions of Qilian Mountains in China are rich in gas hydrate resources. Once greenhouse gases in deep frozen layer are released into the atmosphere during hydrate mining, a series of negative consequences occur. This study aims to evaluate the impact of hydrate thermal exploitation on regional permafrost and carbon budgets based on a multi-physical field coupling simulation. The results indicate that the permeability of the frozen soil is anisotropic, and the low permeability frozen layer can seal the methane gas in the natural state. Heat injection mining of hydrates causes the continuous melting of permafrost and the escape of methane gas, which transforms the regional permafrost from a carbon sink to a carbon source. A higher injection temperature concentrates the heat and causes uneven melting of the upper frozen layer, which provides a dominant channel for methane gas and results in increased methane emissions. However, dense heat injection wells cause more uniform melting of the lower permafrost layer, and the melting zone does not extend to the upper low permeability formation, which cannot provide advantageous channels for methane gas. Therefore, a reasonable and dense number of heat injection wells can reduce the risk of greenhouse gas emissions during hydrate exploitation.

Activity data from a 30-year on-farm experiment with six soil-management treatments were used to develop inventory data for environmental partial life-cycle assessment (LCA). The purpose was to compare the treatments based on environmental outcomes and evaluate conservation agriculture (CA) in Australia's dryland cropping zone. Multiple trade-offs were revealed that highlight the need for a nuanced approach to sustainable intensification and show that rules-based CA is not sufficient to guarantee low greenhouse gas (GHG) emissions, nor low overall environmental impact. Nutrient mining in dryland cropping even under CA can lead to losses in soil carbon that can double GHG intensity. In these systems, additional nutrient inputs can reduce the loss of soil carbon as well as net GHG emissions, demonstrating the critical need to include the effects of soil carbon change in LCA to prevent perverse outcomes. The treatment involving strategic tillage and nutrient balancing, along with stubble retention, had the lowest GHG intensity, but there was a trade-off with the higher embedded impacts across several other environmental categories. Higher fertiliser input could lead to toxicity impacts, due to heavy-metal content, that contribute significantly to the Human health endpoint. However, limitations in modelling such local, site-specific impacts were considerable and more research is needed to address this. In general, trade-offs were found to exist between impacts from on-farm activities versus upstream manufacture of inputs; between GHG emissions and land use (yield) versus other environmental categories; and between different on-farm GHG emission sources. Despite these trade-offs, the treatments all had similar overall scores in the Human health and Ecosystems damage categories. There was no single treatment with low, or high, impact scores across all environmental indicators, indicating that trade-offs need to be carefully considered when making farm-management decisions in the context of net-zero or carbon-neutral farming.

In the context of global warming, increasingly widespread and frequent freezing and thawing cycles (FTCs) will have profound effects on the biogeochemical cycling of soil carbon and nitrogen. FTCs can increase soil greenhouse gas (GHG) emissions by reducing the stability of soil aggregates, promoting the release of dissolved organic carbon, decreasing the number of microorganisms, inducing cell rupture, and releasing carbon and nitrogen nutrients for use by surviving microorganisms. However, the similarity and disparity of the mechanisms potentially contributing to changes in GHGs have not been systematically evaluated. The present study consolidates the most recent findings on the dynamics of soil carbon and nitrogen, as well as GHGs, in relation to FTCs. Additionally, it analyzes the impact of FTCs on soil GHGs in a systematic manner. In this study, particular emphasis is given to the following: (i) the reaction mechanism involved; (ii) variations in soil composition in different types of land (e.g., forest, peatland, farmland, and grassland); (iii) changes in soil structure in response to cycles of freezing temperatures; (iv) alterations in microbial biomass and community structure that may provide further insight into the fluctuations in GHGs after FTCs. The challenges identified included the extension of laboratory-scale research to ecosystem scales, the performance of in-depth investigation of the coupled effects of carbon, nitrogen, and water in the freeze-thaw process, and analysis of the effects of FTCs through the use of integrated research tools. The results of this study can provide a valuable point of reference for future experimental designs and scientific investigations and can also assist in the analysis of the attributes of GHG emissions from soil and the ecological consequences of the factors that influence these emissions in the context of global permafrost warming.

Arctic warming and changing precipitation patterns are altering soil nutrient availability and other processes that control the greenhouse gas balance of high-latitude ecosystems. Changes to these biogeochemical processes will ultimately determine whether the Arctic will enhance or dampen future climate change. At the Cape Bounty Arctic Watershed Observatory, a full-factorial International Tundra Experiment site was established in 2008, allowing for the investigation of ten years of experimental warming and increased snow depth on nutrient availability and trace gas exchange in a mesic heath tundra across two growing seasons (2017 and 2018). Plots with open-top chambers (OTCs) had drier soils (p < .1) that released 1.5 times more carbon dioxide (p < .05), and this effect was enhanced in the drier growing season. Increased snow depth delayed the onset of thaw and active layer development (p < .1) and corresponded with greater nitrous oxide release (p < .05). Our results suggest that decreases to soil moisture will lead to an increase in nitrate availability, soil respiration, and nitrous oxide fluxes. Ultimately, these effects may be moderated by the magnitude of future shifts and interactions between climate variability and ecological responses to permafrost thaw.

Global warming will increase the greenhouse gas (GHG) fluxes of permafrost regions. However, little is known about the difference in GHG fluxes among different types of permafrost regions. In this study, we used the static opaque chamber and gas chromatography techniques to determine the fluxes of carbon dioxide (CO2), methane (CH4), and nitrous oxide (N2O) in predominantly continuous permafrost (PCP), predominantly continuous and island permafrost (PCIP), and sparsely island permafrost (SIP) regions during the growing season. The main factors causing differences in GHG fluxes among three types of permafrost regions were also analyzed. The results showed mean CO2 fluxes in SIP were significantly higher than that in PCP and PCIP, which were 342.10 & PLUSMN; 11.46, 105.50 & PLUSMN; 10.65, and 127.15 & PLUSMN; 14.27 mg m(-2) h(-1), respectively. This difference was determined by soil temperature, soil moisture, total organic carbon (TOC), nitrate nitrogen (NO3--N), and ammonium nitrogen (NH4+-N) content. Mean CH4 fluxes were -26.47 & PLUSMN; 48.83 (PCP), 118.35 & PLUSMN; 46.93 (PCIP), and 95.52 & PLUSMN; 32.86 & mu;g m(-2) h(-1) (SIP). Soil temperature, soil moisture, and TOC content were the key factors to determine whether permafrost regions were CH4 sources or sinks. Similarly, PCP behaved as the sink of N2O, PCIP and SIP behaved as the source of N2O. Mean N2O fluxes were -3.90 & PLUSMN; 1.71, 0.78 & PLUSMN; 1.55, and 3.78 & PLUSMN; 1.59 & mu;g m(-2) h(-1), respectively. Soil moisture and TOC content were the main factors influencing the differences in N2O fluxes among the three permafrost regions. This study clarified and explained the differences in GHG fluxes among three types of permafrost regions, providing a data basis for such studies.

The landscapes in the discontinuous permafrost area of Western Siberia are unique objects for assessing the direct and indirect impact of permafrost on greenhouse gas fluxes. The aim of this study was to identify the influence of permafrost on the CO2 emission at the landscape and local levels. The CO2 emission from the soil surface with the removed vegetation cover was measured by the closed chamber method, with simultaneous measurements of topsoil temperature and moisture and thawing depth in forest, palsa, and bog ecosystems in August 2022. The CO2 emissions from the soils of the forest ecosystems averaged 485 mg CO2 m(-2) h(-1) and was 3-3.5 times higher than those from the peat soils of the palsa mound and adjacent bog (on average, 150 mg CO2 m(-2) h(-1)). The high CO2 emission in the forest was due to the mild soil temperature regime, high root biomass, and good water-air permeability of soils in the absence of permafrost. A considerable warming of bog soils, and the redistribution of CO2 between the elevated palsa and the bog depression with water flows above the permafrost table, equalized the values of CO2 emissions from the palsa and bog soils. Soil moisture was a significant factor of the spatial variability in the CO2 emission at all levels. The temperature affected the CO2 emission only at the sites with a shallow thawing depth.

Autumn freeze-thaw period significantly influenced the soil temperature, moisture, nutrients, and then affected the structure and diversity of soil microbial community. In this paper, three types of wetlands in the permafrost region of Daxing' an Mountains were selected to investigate the greenhouse gas fluxes during the autumn freeze-thaw period. CO2, CH4 , and N2O fluxes during the autumn freeze-thaw period ranged from 24.76 to 124.06 mg m(-2) h(-1),-249.10 to 968.87 mu g m(-2) h(-1), and - 4.21 to 12.86 mu g m(-2) h(-1). CO2 fluxes were mainly influenced by soil temperature and moisture. CH4 fluxes were mainly influenced by temperature and soil moisture. And N2O fluxes were significantly affected by temperature, soil moisture, ammonia nitrogen, and nitrate nitrogen. Environmental factors could explain 64-73.2%, 51-85.4%, and 60.3-93.3% of temporal variation of CO2, CH4, and N2O fluxes, respectively. Comparing different wetlands, the soil temperature was the significant factor to affect the CH4 flux. The global warming potentials during the autumn freeze-thaw period ranged from 717.83 to 775.57 kg CO2-eq hm(-2).

The Early 20th Century Warming (ETCW) in the northern high latitudes was comparable in magnitude to the present-day warming yet occurred at a time when the growth in atmospheric greenhouse gases was rising significantly less than in the last 40 years. The causes of ETCW remain a matter of debate. The key issue is to assess the contribution of internal variability and external natural and human impacts to this climate anomaly. This paper provides an overview of plausible mechanisms related to the early warming period that involve different factors of internal climate variability and external forcing. Based on the vast variety of related studies, it is difficult to attribute ETCW in the Arctic to any of major internal variability mechanisms or external forcings alone. Most likely it was caused by a combined effect of long-term natural climate variations in the North Atlantic and North Pacific with a contribution of the natural radiative forcing related to the reduced volcanic activity and variations of solar activity as well as growing greenhouse gases concentration in the atmosphere due to anthropogenic emissions.

Permafrost (PF)-affected soils are widespread in the Arctic and store about half the global soil organic carbon. This large carbon pool becomes vulnerable to microbial decomposition through PF warming and deepening of the seasonal thaw layer (active layer [AL]). Here we combined greenhouse gas (GHG) production rate measurements with a metagenome-based assessment of the microbial taxonomic and metabolic potential before and after 5 years of incubation under anoxic conditions at a constant temperature of 4 degrees C in the AL, PF transition layer, and intact PF. Warming led to a rapid initial release of CO2 and, to a lesser extent, CH4 in all layers. After the initial pulse, especially in CO2 production, GHG production rates declined and conditions became more methanogenic. Functional gene-based analyses indicated a decrease in carbon- and nitrogen-cycling genes and a community shift to the degradation of less-labile organic matter. This study reveals low but continuous GHG production in long-term warming scenarios, which coincides with a decrease in the relative abundance of major metabolic pathway genes and an increase in carbohydrate-active enzyme classes.