The Sanjiang Plain represents the largest contiguous area of freshwater marshes in China. However, these valuable ecosystems have experienced significant degradation due to anthropogenic disturbances associated with rapid economic development. Investigating the historical impacts of human activities on marsh evolution in this region is crucial for future ecosystem management and conservation. We analyzed a 5700-year sediment core from the Dongfanghong marsh using a multi-proxy palaeoecological approach. Diatom assemblages, together with geochemical characterization, including trace metals, nutrient elements, black carbon (BC) and polycyclic aromatic hydrocarbons (PAHs), were integrated with radiocarbon dating to explore the long-term effects of anthropogenic pressure on marsh evolution and to establish natural baseline conditions for the restoration of degraded freshwater marshes. Our results reveal that the Dongfanghong marsh retained a near-natural state until 1300 cal yr BP, as evidenced by low background concentrations across all geochemical proxies. A gradual rise in population during the Han Dynasty initiated small-scale mining and metallurgy, elevating Pb, Zn and Cu enrichment. As Han Chinese agricultural civilization expanded into the region under the Tang Dynasty, population growth, cropland extension, and industrial emissions drove an increase in N, P, Hg, BC and PAHs. These limited activities had not yet perturbed the marsh ecosystem. Nevertheless, a regime shift occurred at 700 cal yr BP, when fertilizer application, biomass and coal burning, and the discharge of industrial and domestic wastes combined to generate a pronounced anthropogenic depositional signal. Progressive nutrient loading, sedimentary heavy metal enrichment, and organic pollutant deposition have deteriorated water quality and driven a shift toward disturbance-tolerant diatom taxa during the last millennium, with this trend accelerating markedly over the past century. Given their sensitivity to water-chemistry changes, diatoms serve as robust bio-indicators for monitoring water quality and guiding adaptive management of freshwater marshes. The stable state of the Dongfanghong marsh prior to 700 cal yr BP thus provides a valuable reference for restoration targets on the Sanjiang Plain.

Study region: The Sanjiang Plain, which is located in mid-high latitudes and monsoon marginal regions. Study focus: A comprehensive study of long-term hydrological record from climate-sensitive regions is necessary for understanding wetland development and degradation in the context of global warming. This study aims to reconstruct wetland hydrological variations based on multi-proxy during the mid-late Holocene, and to explore how wetland evolution responded to East Asian summer monsoon (EASM). New hydrological insights for the region: Water level fluctuations in Zhuaji Wetland closely followed changes in EASM intensity during the mid-late Holocene. The grain-size median diameter, sand content and the first principal component scores based on diatom collectively indicated a declining water level caused by the weakened intensity of EASM after the Holocene Climatic Optimum. The diatom record clearly documented key climatic events such as the warm and humid Holocene Climatic Optimum and Medieval Climate Anomaly, as well as the cold and dry 4.2 ka event and Little Ice Age, due to its high sensitivity to hydroclimatic variations. The most dramatic diatom compositional change was the increase in dry-indicating species, Hantzschia amphioxys and Pinnularia subcapitata, which began approximately 300 years ago. Sand content also peaked since 0.3 cal ka BP in Zhuaji Wetland. Intensified human disturbance, primarily through agricultural activities, had led to soil erosion, wetland degradation and diatom diversity destruction on the Sanjiang Plain.

Thermokarst lakes represent significant sources of carbon emissions formed through permafrost degradation. However, peatland development at their margins can shift this climate feedback from positive to negative. Understanding the mechanisms driving such peatland development is therefore crucial for interpreting both past and future global carbon cycles. In this study, we analysed seven peat cores from a permafrost peatland located at a thermokarst lake margin in the northern Greater Khingan Mountains, a region highly sensitive to global change. Using palynological data, we quantitatively reconstructed local vegetation cover and evaluated the effects of autogenic and allogenic factors on peatland evolution over the past 70 years. Peat initiation began at 1,300 yr bp through the lateral expansion of floating vegetation mats and vertical sediment accumulation, representing a lake terrestrialisation process. Adequate moisture conditions sustained long-term fen development over the past millennium. However, drought induced by rapid climate warming triggered a drying trend at the thermokarst lake margin since 1980 ce, culminating in a transition from a Cyperaceae-dominated fen to an Ericaceae–Sphagnum-dominated bog after 2000 ce. Sphagnum expansion enhanced peat and carbon accumulation rates following this transition. The fen–bog transition was initiated primarily by large-scale climatic change in the 1980s and subsequently accelerated by autogenic vegetation succession since the 2000s. Our findings underscore the importance of thermokarst lake-margin permafrost peatlands within the global carbon cycle and provide new insights into peatland–climate feedback mechanisms.

Arsenic (As) contamination in soil represents a major challenge to global agriculture, threatening crop productivity and food security, making the development of effective mitigation strategies essential for sustainable farming. Synthetic bacterial communities (SynCom) improve host plants ability to withstand As stress by several mechanisms. It is well known that polyamines (PAs) strengthen the antioxidant defence system, prevent ethylene formation, preserve cell pH, and shield plant cells from the damaging effects of As, and so forth; nevertheless, it is still unknown how SynCom modify PA metabolism to improve plant resistance to As. Pot experiment was carried out to evaluate how SynCom affects root PA homeostasis, hydrogen peroxide (metabolite associated with PA), genes encoding antioxidant system and expression and activities of PA- associated degrading and synthesizing enzymes in rice subjected to As. SynCom inoculated plants exhibited maximum growth attributes, gene expression of two plasma membrane intrinsic protein, leaf water potential, and chlorophyll contents than non-inoculated plants exposed to As stress. With increased activity of PA catabolic enzymes (copper-containing diamine oxidase, CuAO; polyamine oxidase, PAO) and putrescine synthases (ornithine decarboxylase; arginine decarboxylase, ADC), SynCom inoculated plants resulted in higher putrescine and cadaverine concentrations but lower spermidine and spermine contents. Under As stress, the SynCom inoculated plants resulted in up-regulation of spermine synthase gene, OsSPMS, and down-regulation of PA catabolic enzyme genes (OsCuAO6, OsCuAO8, OsCuAO1 and OsCuAO2) and PA synthase genes (OsADC2 and OsADC1). As stressed plants inoculated with SynCom had higher level of expression in OsPAO1, OsPAO2, OsPAO3 as compared to non-inoculated plants, stimulating reactive oxygen species-associated stress responsiveness signaling through low H2O2 levels by enhancing the genes encoding antioxidant defence system (OsCu/Zn-SOD, OsCAT1 and OsMn-SOD). The results of this study showed that SynCom can alter PA metabolism to improve plants' resistance to heavy metals like As. The inoculation of SynCom emerges as a promising strategy to enhance plant resilience against As toxicity by promoting positive interactions and regulatory stress-responsive pathways. Furthermore, the inoculation of SynCom is a viable approach capable of ameliorating heavy metal stress and improving the productivity of crops in the contaminated soil by fostering positive interactions and stress responsive regulatory mechanisms. (c) 2025 SAAB. Published by Elsevier B.V. All rights are reserved, including those for text and data mining, AI training, and similar technologies.

Peatlands are major carbon sinks and play a crucial role in the carbon cycle. Permafrost peatlands in mid-to-high latitude regions are highly sensitive to climate change, leading to the formation of thermokarst lakes in widely distributed areas of permafrost degradation. In this study, seven peat cores from typical peatlands at thermokarst lake margins in the northern Greater Khingan Mountains of northeast China were used to reconstruct the formation age and accumulation history of peatlands, and to analyze the change in the stability of the peatland carbon pool over time. Results show that drought events and local topography influence the lakeward expansion of the peatlands at thermokarst lake margins, with expansion rates ranging from 2 cm yr-1 to 32 cm yr-1. Strongly influenced by hydrological fluctuations and warming, the carbon accumulation of the studied peatlands commenced with a stage of slow accumulation, and then entered a rapid accumulation stage after the 1950s, with the carbon accumulation rates increasing from 45.2 +/- 5.5 g C m-2 yr-1 to 330.5 +/- 14.4 g C m-2 yr-1. Moreover, the stability of the peatland carbon pool has improved with more stable aromatic compounds increasing from 29.3 % to 32.3 %, as peat accumulation has entered a rapid accumulation stage.

Due to the high carbon density in peatland soil carbon pools and the importance of peatland carbon pool stability under global change, the potential factors that influence peatland carbon stability at long-term scales should be clarified. However, related research is still scarce, especially regarding the relationship between peat accumulating process and carbon stability. In this study, we selected a typical peatland formed during the late Holocene in northeast China to reveal the chemical stability of the peatland carbon pool during its formation and to identify its potential driving factors. Our results show that the increase in peat thickness led to a significant increase in aromatic content from 17.1 +/- 1.7 % to 25.1 +/- 1.1 % in the studied peatland at different stages. Due to the shallow peat thickness at the initial stage of peatland formation before 2200 cal. yr. B.P., the peataccumulating process reduced the mineral sources, while the chemical stability gradually increased to maintain the stability of the peatland carbon pool. As the peat thickness continued to increase, the nutrients and minerals supply were stable and the local vegetation and environmental conditions became the major factors altering the chemical stability of the peatland carbon pool after 2200 cal. yr. B.P. The weak decomposition degree, higher amounts of herbaceous plant litter, and cold/wet climate conditions decrease the carbon stability of the peatland carbon pool. Meanwhile, the continued increase in human activities has accelerated carbon turnover and also has increased the chemical stability of the peatland carbon pool after 300 cal. yr. B.P.

Legume-based intercropping, such as the peanut-cotton system, stands out as a promising strategy for enhancing soil ecosystem multifunctionality (EMF); however, the underlying microbial mechanisms driving these enhancements remain inadequately explored. In this study, after implementing peanut-cotton intercropping for six consecutive years, a data set of 13 ecosystem functional indicators including 41 soil variables, was obtained and used to quantify the average EMF index. We investigated changes in microbial keystone taxa in co-occurrence networks, community assembly processes, carbon (C) cycling profiles, and their collective impacts on soil EMF. Soil EMF increased by an average of 140.0 % in the peanut-cotton intercropping system, compared with monoculture systems of both peanut and cotton, driven by significant increases in C-cycling (159.9 %), nutrient provisioning (91.2 %), and microbial growth efficiency functions (53.9 %). The peanut-cotton intercropping system significantly increased the average well-color developments (AWCD), abundance of C-fixation and Cdegradation genes, and related pathways, resulting in a highly vigorous microbial C-cycling profile. The microbial community assembly processes shifted from a balance of stochastic and deterministic processes in monocultures to predominantly deterministic processes (>70 %) in the intercropping system. Additionally, the peanut-cotton intercropping system fostered a more efficient and stable bacterial-fungal cross-kingdom network than the monocultures, characterized by a higher average clustering coefficient, higher robustness, and shorter average path length. This intercropping system also recruited a group of keystone taxa affiliated with Proteobacteria, Actinobacteria, and Ascomycota phyla. The enhancement of EMF in the peanut-cotton intercropping system resulted from the positive impact of key microbial community members and their assembly, C/N ratios, AWCD, and C-fixation and C-degradation genes. Our study provides insights into the complex ecological linkages between microbial communities, C-cycling profiles, and soil ecosystem functions, providing valuable insights into the microbial mechanisms underlying the benefits of intercropping systems.

Permafrost peatlands are critical carbon sinks in terrestrial ecosystems, but the use of prescribed fire in Northeast China threatens the stability of their carbon (C) stocks. The mechanism of low-severity fire (including plant loss and pyrogenic carbon/PyC input) affect soil CO2 emissions from permafrost peatlands is still unknown. Thus, we selected permafrost peatlands in the Great Khingan Mountains (Northeast China) for three years of consecutive fire (fire plots: F plots; fire plots remove PyC: F-B plots) and simulated fire experiments. We found that fire increased CO2 emissions by 2.25-fold. Total soil carbon decreased after fire, while light fraction carbon and the aromatic content of all four fractions increased due to PyC inputs. The labile C (DOC and light fraction C) increased after fire, and the average C distribution of light fraction increased significantly compared to the unburned plots. Soil CO2 emissions was hastened by the rise in post-fire labile C substrate. Further structural equation model (SEM) analysis showed that the labile C substrate predominated under burned conditions, while enzyme activity predominated under unburned conditions for soil CO2 emissions. Labile C substrates in peatland soils are more sensitive to fire and should be considered in carbon cycling studies after fires. In addition, the F-B plots promoted CO2 emissions, while the simulated fire plots did not significantly alter CO2 emissions, so considering only the effect of the PyC produced after the fire on CO2 emissions is incomplete in peatlands. Overall, soil CO2 emissions from permafrost peatlands is determined by changes in soil C fractions after fire, specifically the quantity of labile C, which is regulated by both plant residue and PyC after fire.

ABSTRACTPermafrost peatlands store high amount of soil carbon. These developed on permafrost layers, which are being endangered increasingly by climate change and wildfires. However, limited data exist on the variation in carbon fractions and their effects on the stability of permafrost peatland carbon pools, despite that carbon fractions are widely used in other ecosystems. Here, we considered that peat soils consist of undecomposed plant litter and separated these into five carbon fractions: macro plant residue carbon (MPRC), coarse particulate organic carbon (cPOC), free particulate organic carbon (fPOC), occluded particulate organic carbon (oPOC), and mineral‐associated organic carbon (MAOC). We analyzed the historical variation in these fractions over the past 700 years and their effects on the carbon pool in the Hongtu peatland (HT, northern Great Khingan Mountains, China). Our results showed that MPRC comprised 66.7% ± 7.6% of the carbon pool, whereas oPOC and MAOC accounted for less than 1%. Notably, fPOC, which represented 15.6% ± 6.5% of the total carbon, had a high aromatic content. It may serve as an important stable carbon fraction for the peatland carbon pool. Over the past 700 years, the decrease in proportion of MPRC and increase in proportions of cPOC and fPOC have resulted in significant increases in both carbon content and aromaticity. Warm/dry conditions and high‐intensity fires reduced the accumulation rates (ARs) of MPRC while increasing those of fPOC and cPOC. The high organic carbon content in the HT peatland limited the availability of mineral elements and resulted in MAOC ARs of approximately 0.01 g m−2 yr−1. This was strongly influenced by the regional dust deposition. Cold climates and intense fires caused an increase in dust deposition, which also increased the MAOC ARs.

The formation of peatlands, which are widely known as natural carbon sink ecosystems, is primarily influenced by climate change and local topography. Unlike other pathways of peatland formation, the formation and stability of floating peatlands remain unclear owing to the large amount of water between floating peat mats and sediment. This study selected a typical floating peatland in northeast China and reconstructed the carbon pool formation history and stability of a floating peat mat by employing 14C dating of basal samples from 16 peat cores and FTIR analysis along two typical transects. The results showed that the floating peat mat formed around 1950-1962 CE and laterally expanded until 1975 CE, which indicating the formation of peat mat without exhibiting marked expansion as it floated on the water and the peat mat expansion occurrence under low water level conditions. Along a typical transect from margin to the open water, the carbon accumulation rates and stable carbon compounds in peat cores significantly increased from 19.6 f 0.9 mg center dot cm-2 center dot y-1 to 28.3 f 5.4 mg center dot cm-2 more stable carbon compound accumulation in peat mat, which was located close to the open water. Large amounts of less stable carbon compounds accumulated on the surface of the floating peat mat, increasing the sensitivity of the floating peatland to environmental changes and makes the new carbon sink might shift to carbon source under global climate change. center dot y-1 and 27.9 f 0.9 % to 30.2 f 1.2 %, respectively. Water fluctuations were speculated to result in

Anthropogenic source emissions have caused unprecedented atmospheric environment pollution and natural ecosystem destruction in recent decades. It is necessary to explore the relationships among human, environment and ecosystem in a global change context. Ombrotrophic peatlands are precipitation-dependent and derive nutrients solely from atmospheric deposition, which can document environmental changes continuously. Diatoms preserved in peat sediments are abundant and diverse, and sensitive to hydrological environment changes. Here we reconstructed the historical water table conditions based on diatom from an ombrotrophic peatland in the northern Greater Khingan Mountains, and to assess the influence of climate and human on ecosystem development over the past 150 years. Our results revealed the hydrological condition in Hongtu (HT) peatland was mainly impacted by climate before 1950 AD. HT peatland remained in a pristine state with minimal human interference, as native inhabitants continued to hunt and gather. After the New China was established in 1949 AD, high frequency of fire events caused by rapid population growth, mining and industry destroyed the diatom diversity. Higher water table in HT peatland from 1950 AD to 1965 AD was resulted by higher rainfall. Since 1980 AD, especially after 2000 AD, a suddenly increase of tolerant diatoms species (Achnanthidium minutissimum and Craticula molestiformis) indicated enhanced anthropogenic disturbance. Anthropogenic emissions caused by industrial production and coal consumption increased the atmospheric nitrogen deposition. The abnormal drought of HT peatland was influenced by both climate warming and human activities since 1980s. The recent and strong effects of human activities on peatlands left significantly stratigraphic signals of the Anthropocene in peat deposits. Diatoms have potential to be applied as indicators of long-term hydrological changes in ombrotrophic peatlands, as they are highly sensitive to environmental changes and human disturbance.

Permafrost peatlands, which store nearly 144 Pg of carbon despite covering only 20 % of the permafrost region, are increasingly threatened by wildfires and shifts in organic matter (OM) sources due to climate warming. However, limited data exist on the relationships between fire, OM sources, and carbon dynamics in peatlands under changing climatic conditions. The long-term effects of fire intensity and vegetation shifts on permafrost peatland carbon pools remain poorly understood. In this study, we used a 14C age-depth model to reconstruct historical variations in OM sources and fire intensity based on the chemical properties of OM and pyrogenic carbon in the Hongtu (HT) and Jintao (JT) permafrost peatlands of the northern Great Khingan Mountains, China. We also evaluated their impacts on peatland carbon dynamics over the past millennium. Our results show that shrubs were the dominant OM source, contributing 88.2 +/- 14.6 % of total OM in the JT peat core and 78.8 +/- 21.5 % in the HT peat core. The occurrence of moderate fires promoted a higher proportion of shrubs in total OM. However, a high-intensity fire caused the OM sources to shift from shrubs to herbs, notably in the JT peatland between 300 and 200 cal. yr. B.P., which significantly decreased carbon stability. Compared to herbs and mosses, a higher proportion of shrubs in OM was associated with increased carbon accumulation rates (CARs) and greater long-term carbon stability in permafrost peatlands. As the fire intensity increased, the peatland CARs initially increased and then declined, whereas the carbon pool stability steadily improved. Considering both CARs and carbon stability, a moderate fire intensity was found to enhance the accumulation of more stable carbon in peatland carbon pools over the long term, suggesting that it may be more beneficial for peatland carbon sink functions than other fire intensity levels.

Fire is a key ecological factor in marshes, significantly influencing the nitrogen (N) cycle. The impacts of different fire regimes on marshes have garnered increasing attention. This study aims to reveal the effects of fire regimes on N distribution in marshes. We conducted field experiments with fixed–point prescribed burning in typical Sanjiang Plain freshwater marshes, exploring the influences of various fire regimes on the distribution of N in marshes. We found that in the spring–burned plots, the soil ammonium (NH4+–N) content increased by 318% with thrice–burned approaches compared to once–burned, and by 186% with thrice–burned compared to twice–burned. In the autumn–burned plots, NH4+–N content increased by 168% and 190%, respectively. Similarly, the soil nitrate (NO3––N) content three years subsequent to burning increased by 29.1% compared to one year since burning, and by 5.96% compared to two years since burning in the spring–burned plots (73.8% and 32.9% increases, respectively, in the autumn–burned plots). The plant stem–N content of the autumn burns increased by 30.9%, 119%, and 89.1% compared to the spring burns after one, two, and three years since burning, respectively. Our results indicate that high fire–frequency promotes marsh N cycling within the span of three years. The marsh soil conversion of NH4+–N to NO3––N was enhanced with increased time since burning. High fire–frequency promotes plant growth, exacerbating competition between plant populations, with this effect being more significant in autumn–burned plots than in spring–burned plots.

The driving force of climate change in the monsoon margin is complex, making it a key area for regional and global climate change research. Palaeohydrological studies in the monsoon margin have increased the resolution of research in the long term, transitioning from qualitative to quantitative studies to comprehend climate change processes, patterns, and mechanisms. Testate amoebae (TA) in peat sediments are used as a proxy indicator organism for quantitative reconstruction of palaeohydrology. Thus, their community changes are directly related to precipitation, and widely used to reconstruct the patterns of summer precipitation globally. We investigated TA species and reconstructed palaeohydrological changes in the Greater Khingan Mountains’ Hongtu (HT) peatland, located in the East Asian Summer Monsoon (EASM) margin. The result showed that the most abundant TA species were Assulina muscorum (12.4 ± 5.0%) and Nebela tincta (8.9 ± 4.9%) in the HT peat core. The increase in dry indicator species (e.g., A. muscorum and Alabasta militaris) indicated a drying pattern in the HT peatland since 150 cal yr BP. Principal component analysis (PCA) explained 47.6% of the variation in the selected TA assemblages. During 400 to 250 cal yr BP, PCA axis 1 scores ranged from 0.2 to −1.3 (reflecting a drier climate), associating with the Little Ice Age. The paleohydrology of the northern part of the Greater Khingan Mountains was mainly controlled by the EASM, which was associated with changes in North Atlantic Sea surface temperature and solar radiative forcing. The apparent drying pattern may be the result of the gradual intensification of anthropogenic activities and the increase in EASM intensity.

In the context of global climate change, it is crucial to design cropping systems with high and stable crop yields. Recent studies have shown that intercropping systems can improve productivity and enhance yield stability. However, the results remain much uncertainty due to variations in cropping system and environment along with other factors. Here, a 5-year study was conducted to investigate the overyielding, temporal yield stability, and underlying mechanisms in cotton-based intercrops (i.e., garlic/cotton, wheat/cotton, and peanut/cotton). Overall, cotton-based intercrops outperformed the monocultures by 17.6% on average, with the overyielding probabilities of 71%. We show for the first time that cotton-based intercropping systems significantly reduced the risk of yield failure (yields below the 10th percentile) by 12.4% and increased the upside potential of yield (yields above the 90th percentile) by 9.3% relative to monoculture systems. Intercropping systems also increased temporal yield stability by 36.8% compared with monocultures. However, overyielding and yield stability varied between the three intercropping combinations, with garlic/cotton and wheat/cotton intercropping showing the greatest improvements. The temporal stability of crop yield slightly increased, while the probabilities of years with major declines in crop yield greatly decreased. Enhanced yield gain from cotton-based intercropping systems compared with monoculture was strongly and positively correlated with the complementarity effect, which suggested that niche partitioning and facilitative effects of two components were main mechanisms driving yield gain. In addition, temporal yield stability was positively correlated with yield and compensatory dynamics. Thus, diversified cropping systems through garlic or wheat/cotton intercropping can be used as a promising way to move toward more sustainable agriculture while maintaining a sufficient level of crop production.

By quantifying the soil water movement (SWM) in crop planting systems, we can better understand the soil water consumption (SWC) and crop yield relationship; this finding is significant for determining the field water cycle and reducing agricultural water waste. In this paper, a case study was conducted on cotton production. Soil moisture sensors were set at depths of 10-110 cm under three cotton cropping systems (monoculture cotton (MC), wheat/delayed intercropped cotton (WIC), and wheat/direct-seeded cotton (WDC)) based on spatial grid methods; a geostatistical grid calculus was used to calculate SWM; and the crop and meteorological influence mechanisms on cotton lint yield were comprehensively analyzed. At the squaring stage, SWC and vertical SWM were significantly correlated with light, temperature and water conditions. At the flowering and boll development stage, SWC and vertical SWM were collectively affected by meteorological conditions and crops, and they were positively correlated with lint yield. The aboveground and belowground biomass accumulation at the flowering and boll development stage positively affected vertical SWM in and between cotton rows. Vertical SWM in cotton rows increased SWC in cotton rows. SWC in cotton rows and aboveground biomass positively impacted lint yield formation; SWC between rows negatively impacted lint yield. The SWC and vertical SWM between rows in the MC seedling stage exceeded those in cotton rows, and more precise irrigation at the seedling stage reduced water waste. The WIC horizontal SWC at the squaring and flowering and boll opening stages was relatively high, moving from the row midline to cotton row. A better SWC distribution in and between cotton rows promoted water utilization in the cotton rows; this method was feasible for improving cotton yield in diverse planting systems. The results could optimize precision irrigation management at different cotton growth stages and provide a theoretical reference for promoting sustainable agricultural production and climate adaptation.

The serious problem of residual film pollution in the arid region of northwestern China has a severe negative impact on both the farmland environment and the benefits of cotton planting. Drip irrigation without mulch (DIWM) has the potential to serve as an effective alternative to mulch drip irrigation and address the issue of residual film pollution. However, there are few studies on how to formulate a rational irrigation regime under DIWM conditions and achieve water savings and productivity gains. Consequently, from 2020 to 2021, we established three DIWM treatments: W4, W6, and W8. None of the treatments were irrigated at the seedling stage, and the irrigation regime was the same for all the treatments at the squaring stage (2 irrigations at an irrigation quota of 45 mm). From the initial flowering stage, the frequency of irrigation was once every 6 d, 8 d, and 12 d for W4, W6, and W8, respectively, and the corresponding total numbers of watering times were 8, 6, and 4, respectively. The irrigation amount was 69 mm at each time point during the flowering and boll-forming stages in all the treatments, and the final irrigation amount was 52.2 mm in W8. The total irrigation amounts were 366 mm, 504 mm and 625.2 mm for W4, W6 and W8, respectively. This study explored the spatiotemporal characteristics of soil moisture via sensors combined with the spatial grid method. Additionally, the growth indices, biomass accumulation, yield components, and water use efficiency (WUE) of cotton were assessed across various treatments. The results revealed that, in 2020 and 2021, the W8 treatment resulted in the highest soil water content (SWC) in the 70-110 cm soil layer and soil water consumption (WC) in the 10-110 cm layer, with the WC in the 10 cm layer being 20% and 44% greater than that in W6, respectively. The excessive total irrigation amount (IA) in the W8 treatment led to high vegetative growth of cotton, diminishing the positive impact on yield. Across both years, the WUE observed in the W6 treatment significantly exceeded that of W8, while the seed cotton yield demonstrated only marginal decreases of 5% and 0.9% compared with that of W8. The irrigation amount and average WC in the 10-40 cm soil layer were 19% and 29% lower in W6 than in W8, respectively, but the economic benefits were only 2 % lower than those in W8. There was a significant positive correlation between the SWC and WC in all the different soil layers, and the effect of the SWC on the WC gradually decreased with increasing soil depth. Overall, the irrigation regime employed in the W6 treatment within the arid zone, devoid of mulch cover, proves to be an effective water-saving strategy, ensuring a consistent cotton yield and enhancing WUE. This study serves as a reference for developing an efficient irrigation system tailored to the DIWM cotton industry in arid zones, contributing to the promotion of green and sustainable agricultural development in this region.

Peatlands store vast amounts of soil carbon and the stability of this carbon pool plays a crucial role in the carbon dynamics under global change. In the Sanjiang Plain, one of the important peatlands distributed region in China, peatlands were seriously affected by the regional land reclamation during the last century. While, there is a scarcity of data evaluating the impact of land reclamation on peatland carbon stability. Here, based on 210 Pb dating of the Shenjiadian (SJD) peatland, we reconstructed historical variations in peatland carbon stability and assessed its response on regional land reclamation over the last century in the Sanjiang Plain. The results showed that the highest aromatic content (25.2 +/- 0.7 %) and the lowest carbohydrate content (34.7 +/- 2.5 %) occurred between 1950 and 1980, coinciding with the period of extensive second land reclamation in the Sanjiang Plain. The increase in regional human activities led to greater accumulation of pyrogenic carbon in the peatland, enhancing carbon stability in the 1950 s. However, as farmland area continued to grow in the 1960 s, local fires caused by agricultural activities led to more frequent peat fires, promoting the accumulation of herbaceous litter in the peatland, which decreased the stability of the peatland carbon pool but increased carbon accumulation rates. With the proportion of shrub litter increasing and regional land reclamation weakening after 1980, the accumulation of shrub litters has increased both carbon stability and carbon accumulation rates in the studied peatland, particularly after 2000.

Improvement of cultivated cotton adaptability to extreme climate events under climate change promotes sustainable cotton production. Extreme rainfall leads to a significant decrease in cotton yield, which may be related to changes in soil water consumption (SWC) and the vertical distribution of yield, but relevant research is still scarce. Here, a two-year cotton sowing date experiment was conducted in which geostatistics, sensor technology, the spatial grid method, and principal component analysis were combined to analyze cotton utilization of soil water during extreme rainfall (2021) and normal (2022) years. The reasons for cotton yield reduction under extreme rainfall and strategies to improve cotton production adaptability to extreme rainfall were discussed. Under extreme rainfall, the morphogenesis and reproductive organ development of cotton were inhibited. The accumulation of SWC and its relationship with the biomass accumulation of cotton on different sowing dates under extreme rainfall exhibited nearly opposite characteristics to those in a normal year. Simultaneously, the two-year yield showed the opposite trend with the change in sowing date. There existed a trade-off strategy for the vertical distribution (i.e., on the upper, middle and lower fruiting branches) of cotton yield. Extreme rainfall reduced the yield at lower fruiting branches and increased the boll-forming rate of the upper fruiting branches, which was closely related to seed cotton yield, lint yield and water productivity (WP). Optimizing the cotton sowing date (early sowing should be appropriate in this study) may improve the adaptability of cotton production under extreme rainfall, but further long-term studies are needed. This study highlights the critical practice of climate-smart agriculture and has reference value for the sustainable development of cotton production.