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As a main grain production area in China, Northeast China (NEC) is highly influenced by the higher warming trend than elsewhere in China or even the globe. As the warming trend goes on, scientific understanding of the changes of thermal conditions in NEC will be essential for taking agricultural adaptation measures. In this paper, the high-resolution (25 km) corrected outputs of PRECIS (Providing Regional Climates for Impacts Studies) under the Representative Concentration Pathway 4.5 (RCP4.5) scenario were used to analyze the changes of the agro-climatic thermal resources in NEC. Results showed that accumulated temperature ≥10 °C (AT10) could increase by 300–500 °C·day, 500–900 °C·day, and 750–1000 °C·day in 2011–2040 (2020s), 2041–2070 (2050s), and 2071–2100 (2080s), respectively, relative to the baseline period of 1961–1990. The potential growing season (PGS) would then be prolonged by 11–19 days, 23–35 days, and 25–37 days in 2020s, 2050s and 2080s, respectively, compared to baseline. The spatial features for the changes of thermal indices would show a large increase of AT10 and an extension of PGS and Frost-free period (FFP) in mountainous areas compared to plains; the increment of AT10 would be greater in southern NEC than that in the north, with over 1000 °C·day in the southern parts and 700–800 °C·day in the northern parts in the 2080s. Additionally, the three thermal indices would increase rapidly from 2020s to 2050s compared to the period from 2050s to the 2080s, coincides with the greenhouse gas concentrations peak around the mid-period of the 21st century, and the decline towards the end of the 21st century under RCP4.5 forcing. The results of this paper could act as a guide to taking advantage of increasing thermal resources in NEC, and would be helpful for local practitioners in decision-making. [ABSTRACT FROM AUTHOR]

• This paper proposes to optimize the resource allocation of the food and energy waterl;. • Deepen the reform of the supply side of agriculture to alleviate the stress on water resources;. • The contradiction of water shortage will become more prominent in Northeast China. The production and consumption of grain and energy need physical water resources which causes the virtual water circulation. The recycling of water requires energy, and the food production is associated with the consumption of biomass energy, which competes with the energy production for water. This paper uses the water footprint of food production and Water pressure index corrected to calculate Production and transfer of food and energy in Northeast China. The results show that the energy water footprint of the Northeast region was 4.3 × 108 m3 In 2000, it reached a maximum value of 4.39×108 m3 in 2012, and whereafter the energy water footprint fell to only 3.73×108 m3 in 2015. In Northeast China, more water is embedded in the outflow of food and in the inflow of energy. In 2000, the energy water footprint outflow was 1.54×108 m3, and the energy water footprint inflow in 2015 reached 1.89×108 m3. With the expansion of the food and energy production in Northeast China, water resources stress continues to rise. Except for Liaoning Province, the water resources pressure indices of Heilongjiang Province and Jilin Province are much higher than the national average. [ABSTRACT FROM AUTHOR]

Inactive ice wedges are still present today at Yituli'he in the middle Da Xing'anling (Greater Hinggan) Mountains in northeastern China, which is the southernmost known site (50°37′N) with ice wedges in the Northern Hemisphere. However, it is uncertain whether the ice-wedge isotope composition, characterized by low δ18O, δD and low deuterium excess values, is representative of the isotope signature of a broader region. In this paper, the ice-wedge isotope compositions were examined in the context of the stable isotopes of precipitation from the nearby Global Network of Isotopes in Precipitation ( GNIP) stations. In addition, the pollen spectra from the host sediments were analysed to provide additional information on local vegetation in order to better understand the climate conditions favouring ice-wedge formation. The pollen spectra suggest that the Yituli'he ice wedges developed during the colder and wetter period after 6000 cal. a BP. The isotopes in the Yituli'he ice wedges are consistent with the isotope background recorded in atmospheric precipitation collected at the nearby GNIP stations. When the snow-melt froze into ice veinlets, the isotope signals did not change substantially because of the strong, cold, continental anticyclones in winter as well as a strong temperature inversion that prevail in the Da Xing'anling Mountains. As the climate pattern did not change substantially, the neoglacial cold period is unlikely to have allowed for strong secondary fractionation of isotope records during ice-wedge formation. Thus, the annual isotope signature can be interpreted as a valid archive of climate data. [ABSTRACT FROM AUTHOR]

Zircon U-Pb ages, Hf isotope data and whole-rock major and trace element data for the Middle to Late Ordovician gabbros and granites in the Erguna Massif, NE China were presented in this paper. The petrogenesis of these rocks and the Early Paleozoic tectonic evolution of the massif were discussed. Zircons from the granites and gabbros are of magmatic origin based on their cathodoluminescence (CL) images. The Pb/U ages obtained from 20 spots on zircons from the granites range from 446±9 to 464±10 Ma, yielding a weighted mean age of 455±10 Ma; and 16 spots on zircons from the gabbros range from 465±10 to 466±7 Ma, yielding a weighted mean age of 465±2 Ma. Chemically, the Late Ordovician granites in the Erguna Massif are weakly peraluminous and similar to A-type granites. The granites and gabbros are all enriched in light rare earth elements and large ion lithophile elements (e.g., Rb, K), and depleted in heavy rare earth elements and high field strength elements (e.g., Nb, Ta, and Ti); they all exhibit marked negative Eu anomalies. Their zircon ɛ( t) values range mainly from +1.86 to +6.21 (for the granites) and +1.39 to +3.89 (for the gabbros), except for one spot with a value of −0.27 (for a gabbro). The T ages for the gabbros and T ages for the granites vary from 928 to 1 091 Ma and from 1 287 to 1 675 Ma, respectively. It is concluded that the primary magma of the granites could have been derived by partial melting of Mesoproterozoic newly accreted crustal material, whereas the primary magma of the gabbros originated by partial melting of a depleted mantle wedge that had been metasomatized by fluids derived from a subducted slab. These Middle-Late Ordovician granites and gabbros constitute a typical bimodal igneous rock association, implying an extensional environment that was probably related to the post-collisional development of the Erguna and Xing'an massifs in the early Early Paleozoic. [ABSTRACT FROM AUTHOR]

Extreme climate events frequently exert serious effects on terrestrial vegetation activity. However, these effects are still uncertain in widely distributed areas with different climate zones. Transect analysis is important to understand how terrestrial vegetation responds to climate change, especially extreme climate events, by substituting space for time. In this paper, seven extreme climate indices and the Normalized Difference Vegetation Index (NDVI) are employed to examine changes in the extreme climate events and vegetation activity. To reduce the uncertainty of the NDVI, two satellite-derived NDVI datasets, including the third generation Global Inventory Monitoring and Modeling System (GIMMS-3g) NDVI dataset and the NDVI from the National Oceanic and Atmospheric Administration (NOAA) satellites on Star Web Servers (SWS), were employed to capture changes in vegetation activity. The impacts of climate extremes on vegetation activity were then assessed over the period of 1982–2012 using the North–South Transect of Eastern China (NSTEC) as a case. The results show that vegetation activity was overall strengthened from 1982 to 2012 in the NSTEC. In addition, extreme high temperature events revealed an increased trend of approximately 5.15 days per decade, while a weakened trend (not significant) was found in extreme cold temperature events. The strengthened vegetation activities could be associated with enhanced extreme high temperature events and weakened extreme cold temperature events over the past decades in most of the NSTEC. Despite this, inversed changes were also found locally between vegetation activity and extreme climate events (e.g., in the Northeast Plain). These phenomena could be associated with differences in vegetation type, human activity, as well as the combined effects of the frequency and intensity of extreme climate events. This study highlights the importance of accounting for the vital roles of extreme climate effects on vegetation activity. [ABSTRACT FROM AUTHOR]

Previous studies have established a link between fluctuations in climate and increased mortality due to coronary artery disease (CAD). However, there remains a need to explore and clarify the evidence for associations between meteorological changes and hospitalization incidences related to CAD and its subtypes, especially in cold regions. This study aimed to systematically investigate the relationship between exposure to meteorological changes, air pollutants, and hospitalization for CAD in cold regions. We conducted a cross-sectional study using hospitalization records of 86,483 CAD patients between January 1, 2009, and December 31, 2019. Poisson regression analysis, based on generalized additive models, was applied to estimating the influence of hospitalization for CAD. Significant associations were found between low ambient temperature [-10°C, RR = 1.65; 95% CI: (1.28–2.13)] and the incidence of hospitalization for CAD within a lag of 0–14 days. Furthermore, O3 [95.50 μg/m3, RR = 12; 95% CI: (1.03–1.21)] and NO2 [48.70 μg/m3, RR = 1.0895% CI: (1.01–1.15)] levels were identified as primary air pollutants affecting the incidence of CAD, ST-segment-elevation myocardial infarction (STEMI), and non-STEMI (NSTEMI) within the same lag period. Furthermore, O3 [95.50 μg/m3, RR = 1.12; 95% CI: (1.03–1.21)] and NO2 [48.70 μg/m3, RR = 1.0895% CI: (1.01–1.15)] levels were identified as primary air pollutants affecting the incidence of CAD, ST-segment-elevation myocardial infarction (STEMI), and non-STEMI (NSTEMI) within the same lag period. The effect curve of CAD hospitalization incidence significantly increased at lag days 2 and 4 when NO2 and O3 concentrations were higher, with a pronounced effect at 7 days, dissipating by lag 14 days. No significant associations were observed between exposure to PM, SO2, air pressure, humidity, or wind speed and hospitalization incidences due to CAD and its subtypes. Our findings suggest a positive correlation between short-term exposure to low ambient temperatures or air pollutants (O3 and NO2) and hospitalizations for CAD, STEMI, and NSTEMI. These results could aid the development of effective preparedness strategies for frequent extreme weather events and support clinical and public health practices aimed at reducing the disease burden associated with current and future abnormal weather events. [ABSTRACT FROM AUTHOR]

This article examines the 1901–1904 discussions about free trade in the Priamur region and the territories in Chinese Manchuria leased to the Russian Empire. The discussions are placed in the contexts of nationalising empire, Russian imperialism, and cosmopolitan society of the globalised free port of Vladivostok. The piece traces the place of ideas about free trade in the social and political imagination of contemporaries in the Priamur region to show how these images were challenged by imperial expansion in Manchuria. It also analyses the rhetorical strategies used by regional actors to re-negotiate the borders of economic and political expansion, as well as the internal and external comparisons they made. The article demonstrates how debates about free trade in the Russian Far East offer deeper insight into how ideas about free trade and free ports as institutions affected not only the economic but social and political transformations in the late imperial period. [ABSTRACT FROM AUTHOR]

This paper presents accounts of seven travelogues, written by Hungarian travellers and professionals who visited or worked in Manchuria between the end of the nineteenth and beginning of the twentieth centuries. So far these texts have not received wide scholarly attention because they are accessible only in Hungarian, although they contain unique first-hand observations of the construction of the Eastern Chinese Railway and many ethnographic notes. The author suggests that some narratives, especially those written by Hungarians who worked as engineering specialists, present very balanced analysis of the situation, because they belonged neither to the colonising project in China, nor to the colonised side, but rather were enthusiasts of technological modernisation. As a theoretical frame, the author attempts to apply notions and concepts developed by infrastructural and cybernetic anthropology. [ABSTRACT FROM AUTHOR]

National loss of territory is commonly described in corporeal language of mutilation and dismemberment. In this paper I argue that this language is not simply poetic or metaphoric but that it reflects a genuine association between the individual body and the national contours, and that this identification has been greatly facilitated by the emergence of the national map. In revisiting the common trope of the nation-as-body through inclusion of insights from neuroscience, I explore what happens when a lack of fit intervenes between the physical geographical extent of the nation and the mental map held by its inhabitants. Taking Manchuria as my main focus while suggesting a much wider applicability, I suggest that 'lost' territories, no longer included within the national body, remain nonetheless part of a previous national incarnation. As such, they draw national sentiments and affect, eliciting what can be labeled 'phantom pains'. [ABSTRACT FROM AUTHOR]

The Khitan took the historical chance at the beginning of the 10th century to conquer north China and southern Manchuria and found the Liao Dynasty (907-1125), which stood in north Asia for more than two hundred years as rival for the Chinese dynasties in the south. In their effort to rule such a multi-ethnic and multi-cultural empire, the Liao rulers created a unique dual political system, in which two different sets of political institutions were established for the Khitan and the Han-Chinese respectively. The Liao central government was comprised of the northern and the southern administrations: the northern administration was responsible for Khitan and other nomadic tribes, while the southern administered Han-Chinese and Bohai. On the local level, traditional tribal organs of the Khitan were kept parallel to Han-Chinese prefectures and counties. This paper attempts to trace the origin and historical developments of this dual system, to identify various factors which helped to shape its form, and finally to discuss in detail various administrative institutions of this dual system in the Liao central and local governments. [ABSTRACT FROM AUTHOR]

This paper reports the analysis on cores and rock slices, data on seismic and logging activities, characteristics of core samples, and the paleogeographic background of the Yingcheng Formation of the Xujiaweizi faulted depression in the Songliao Basin. The results show that some of the volcanic rocks were formed during subaquatic eruptions. These subaqueous volcanic rocks are further characterized by the interbedded black mudstone and tuffite, the presence of double-layer perlite enclosing aphyric or sparsely phyric rhyolite, the presence of a bentonite layer, and the coefficient of oxidation (FeO/FeO). The types of rocks are volcanic breccia, lava breccias, perlite, rhyolite, tuff and sedimentary tuff. The subaquatic eruptions are distributed mainly in Wangjiatun, Shengping, Xuxi, Xuzhong, and Xudong. The XS-1 area is the most typical. The organic abundance of overburden mud rocks within the volcanic rocks of the Yingcheng Formation indicates that these rocks represent high-quality source rocks. The analysis also shows that continental subaquatic volcanic eruptions provide a rich supply of minerals and energies for the lake basin and increase the organic matter content in the water. Moreover, the water differentiation provides a good reducing environment for the conservation of organic matter, and is beneficial for the formation of high-quality source rocks. Finally, we propose a hypothesis to describe the mode of subaquatic eruptions and the formation of high-quality source rocks. [ABSTRACT FROM AUTHOR]

By using crater impact morphological theory and mathematics modeling, the paper studies the cratering process and morphological features of the Xiuyan Crater in Northeast China based on remote sensing imagery, digital elevation model (DEM) and drilling and measuring data. The results show that: 1) Simulated calculation indicates the diameter of the transient crater was 1406±12 m and the depth was 497±4 m. The diameter of the final crater was 1758±15 m and the depth was 374.5±3.5 m; the thickness of the breccia lens was 188.5±0.5 m. The data is basically the same as previous drilling data. 2) Preliminary determination of the size of Xiuyan impactor: The diameter at about 55 m for an iron meteorite, and about 115 m for a stony meteorite. 3) The depth-to-diameter ratio is 0.143, similar to the typical simple crater. The circularity index of the Xiuyan Crater is 0.884, indicating erosion and degradation. 4) The distribution pattern of radial fractures has priority in NW-SE and WNW-ESE and these fractures control the development and evolution of drainage inside the crater. [ABSTRACT FROM AUTHOR]

This paper investigates monthly and seasonal precipitation-temperature relationships (PTRs) over Northeast China using a method proposed in this study. The PTRs are influenced by clouds, latent and sensible heat conversion, precipitation type, etc. In summer, the influences of these factors on temperature decrease are different for various altitudes, latitudes, longitudes, and climate types. Stronger negative PTRs ranging from −0.049 to −0.075 °C/mm mostly occur in the semi-arid region, where the cold frontal-type precipitation dominates. In contrast, weaker negative PTRs ranging from −0.004 to −0.014 °C/mm mainly distribute in Liaoning Province, where rain is mainly orographic rain controlled by the warm and humid air of East Asian summer monsoon. In winter, surface temperature increases owing to the release of latent heat and sensible heat when precipitation occurs. The stronger positive PTRs ranging from 0.963 to 3.786 °C/mm mostly occur at high altitudes and latitudes due to more release of sensible heat. The enhanced atmospheric counter radiation by clouds is the major factor affecting increases of surface temperature in winter and decreases of surface temperature in summer when precipitation occurs. [ABSTRACT FROM AUTHOR]

In Northeast China during the winter, severe snowstorms can occur resulting in both societal and economic damage. In this paper, we explore an effective technique for the seasonal prediction of heavy snow activity, where previous synoptic studies have failed. We employ a year-to-year increment approach and ultimately identify four predictors, x to x. x is the area-averaged soil moisture over the northern part of Northeast China in the preceding month of September and represents the role of land processes. x represents the role of sea-air interactions in winter, x the preceding summer Mascarene High related to the winter SST over the tropical western Pacific, and x is the low-level the thermal condition over Northeast China from the previous year that oppose current year. Cross-validation tests for both 1963-2011 and independent hindcasts between 1983-2010 are performed to validate the prediction ability of our technique. The cross validation test results for 1963-2011 reveal a high correlation coefficient of 0.86 (0.77) between the predicted and observed year-to-year increment of the number of snow days. The model also predicts well the independent hindcast for the years 1983-2011. Therefore, this study provides an effective climate prediction model for Northeast China's heavy snow activities and thus requires preliminary application in operational settings. [ABSTRACT FROM AUTHOR]

In this paper, an integrated indicator-based system is established to map the suitability of spring soybean cultivation in northeast China. The indicator system incorporates both biophysical and socioeconomic factors, including the effects of temperature, precipitation, and sunshine on the individual development stages of the spring soybean life cycle. Spatial estimates of crop suitability derived using this indicator system are also compared with spring soybean planting areas to identify locations where there is scope for structural adjustment in soybean farming. Results of this study indicate that northeast China is moderately suited to spring soybean cultivation. Areas classified as suitable, moderately suitable, and unsuitable for soybean cultivation, respectively, occupy approximately 9.09 × 104, 11.45 × 104, and 7.99 × 104 km2, accounting for 11.5%, 10.11%, and 14.49% of the total area of northeast China. The Songnen and Sanjiang Plains are identified as the most and least suitable places, respectively, for spring soybean growth. A comparative analysis indicates that the suitable, moderately suitable, and unsuitable areas account for 24.78%, 46.30%, and 28.92%, respectively, of the total area presently under soybean cultivation. The analysis suggests that soybean cultivation in Heilongjiang Province is generally unfavorable, with equivalent percentages of 15.39%, 51.70%, and 32.91%. Results suggest that agricultural structural adjustment may be required to encourage farmers to grow spring soybeans. It is anticipated that this study will provide a basis for follow-up studies on crop cultivation suitability. [ABSTRACT FROM AUTHOR]

This paper reviews the current evidence for settlement patterns and ceremonial activity amongst Hongshan Neolithic groups in northeastern China, with particular attention to the well-known ceremonial site at Niuheliang. We consider the location of Hongshan ceremonial sites in their wider landscape settings, arguing that such sites are a chronologically late stage of Hongshan ceremonial investment and that, within these broad complexes, the most impressive architecture and portable goods come from an especially late phase of activity. These more impressive localities were also particularly privileged places in terms of their access to major routes, specific kinds of local geology and integrated patterns of visibility. In contrast to more loosely organized Hongshan residential sites of similar size, ceremonial centres such as Niuheliang (and, within these, certain important sub-localities) clearly functioned as key mechanisms for social, political and regional stratification around roughly the mid 6th millennium BP. [ABSTRACT FROM AUTHOR]

This paper analyzes the large-scale atmospheric circulation characteristics of anomalous cases of January temperatures that occurred in Northeast China during 1960-2008 and precursory oceanic conditions. The January monthly mean surface air temperature (SAT) anomalies and the duration of low temperature are used to define temperature anomaly cases. The anomalous cyclonic circulation over northeast Asia strengthens the northerly flow in cold Januarys, while the anomalous anticyclonic circulation weakens the northerly flow in the warm Januarys. The negative (positive) North Pacific sea surface temperature anomaly (SSTA) and increased (decreased) sea ice concentration in the Barents-Kara seas in the preceding month are probably linked to the cyclonic (anticyclonic) circulation pattern over northeast Asia in the cold (warm) cases. Further analyses indicate that the preceding oceanic conditions play distinct roles in the SAT anomalies over Northeast China on different time scales. Strong relationships exist between North Pacific SSTA and the SAT in Northeast China on the interannual time scale. On the other hand, the sea ice concentration is more closely associated with the interdecadal variations of SAT in Northeast China. [ABSTRACT FROM AUTHOR]

The investigation of the violent crimes that had turned civil cases to criminal cases in four prisons in Northeast China has discovered a special kind of disputes in Rural China. Its extensive occurrence signifies failure of the order-restorative power of folk forces in specific contexts. This kind of disputes has not yet been dealt with or taken in by the state legal system. This paper analyzes seven cases in depth to reveal the realistic picture of the rural order behind disputes of this kind. Contrary to the assumptions of the traditional folk legal theories, the "external nature" in the state legal order provides a feasible channel for the increasing number of "strangers" to obtain protection. However, execution of the state laws depends upon the political operations at the local level, whose coordinating role relies upon the cooperation of the folk order. Failure of the folk order in mediating disputes forces state laws to intervene directly to the individuals' actual needs but the ineffectiveness in the intervention in turn heightens the disappointment of the individuals in the state laws. Meanwhile, the close ties between the state legal system and the local political operations are likely to lead to suspicion of the independence of the state laws. In such a context, "despotism" may turn up to endanger the rural society. The powerful persons may use the state's power that can penetrate and control society to undermine the power of the traditional order in a top-down fashion but at the same time they may undermine the legitimacy of the state's legal order in a bottom-up fashion via the same origin shared by the state laws and the state power. [ABSTRACT FROM AUTHOR]

Abstract: In this paper, we propose a method to predict ultra-short term wind power production with chaotic time series. Through analysis of the data measured from real wind farm, the ultra-short term prediction model of wind power is established based on the space theory of chaotic time series phase. The wind power of a real wind farm in northeast China in some future time including 15 m, 30 m and 1h are predicted by the prediction model finally. Test results are presented in the paper. [Copyright &y& Elsevier]

The analysis of heavy metals is very important for assessing the feasibility of the agricultural utilization for the municipal sludge. In this paper, a four-step sequential extraction method was applied to extract heavy metals (Cu, Zn, Mn, Cr, and Ni) in municipal sludges from seven individual wastewater treatment plants located in Jilin and Heilongjiang Province, China, for estimating the mobility and bioavailability of the metal ions in the agricultural application. The total concentrations of heavy metals and their chemical fractions after the sequential extraction were determined. Principal component analysis (PCA) was applied to analyze the relations of heavy metals fractions in the municipal sludges. Experimental results indicated that the total concentrations of Cu, Zn, Cr, and Ni in all sludge samples were below the threshold values set out by the Chinese legislation (GB18918-2002). Specially, Zn had a high bioavailability and mobility, Cu and Cr had potential bioavailability, while Mn mainly existed in the residual fraction of municipal sludge. On the other hand, Ni had different mobility in different municipal sludge. PCA results were confirmed by the environmental behavior of heavy metals. [ABSTRACT FROM AUTHOR]

Korean pine (Pinus koraiensis Sieb. et Zucc.) is one of the highly commercial woody species in Northeast China. In this study, six nonlinear equations and artificial neural network (ANN) models were employed to model and validate height-diameter (H-DBH) relationship in three different stand densities of one Korean pine plantation. Data were collected in 12 plots in a 43-year-old even-aged stand of P. koraiensis in Mengjiagang Forest Farm, China. The data were randomly split into two datasets for model development (9 plots) and for model validation (3 plots). All candidate models showed a good perfomance in explaining H-DBH relationship with error estimation of tree height ranging from 0.61 to 1.52 m. Especially, ANN models could reduce the root mean square error (RMSE) by the highest 40%, compared with Power function for the density level of 600 trees. In general, our results showed that ANN models were superior to other six nonlinear models. The H-DBH relationship appeared to differ between stand density levels, thus it is necessary to establish H-DBH models for specific stand densities to provide more accurate estimation of tree height. [ABSTRACT FROM AUTHOR]

Research on the Japanese living in Manchukuo in August 1945 has generally fostered the assumption that all Japanese there wanted to return to Japan as soon as possible. Yet, some made the conscious and voluntary decision to stay, at least for the short to medium term. Among those who chose to delay repatriation were a number of technicians employed by Mantetsu's (South Manchurian Railroad Company) Chūo Shikenjo. This paper looks at the political and personal realities faced by these technicians when making their decisions as whether to stay or leave in terms of the concepts of voluntary and involuntary repatriation. It shows that the circumstances faced, and consequently the decisions made by the technicians, differed over time. It argues that there were three main reasons behind any decision to stay: pragmatism, a sense of responsibility for Japan's activities during the war and a sense of loyalty. [ABSTRACT FROM PUBLISHER]

Abstract: In their recent paper, ; Anti-phase oscillation of Asian monsoons during the Younger Dryas period: Evidence from peat cellulose δ13C of Hani, Northeast China, Palaeogeography, Palaeoclimatology, Palaeoecology 297, 214–222) discuss bulk peat sample cellulose δ13C data from a fen in northeast China as a proxy for East Asian summer monsoon intensity during the Late Glacial period. Based on their own results, cited papers, and an extensive re-interpretation of sedimentological and palynological data from nearby Lake Sihailongwan, construct a hypothesis of contrasting moisture conditions in northern and southern China, with wet conditions in the north during the Younger Dryas period and an anti-phase behaviour of Indian- and East Asian summer monsoon intensity. However, we do not approve of the re-interpretation of our Lake Sihailongwan data by and must strongly reject it. We show here that neither the fen data, nor the Lake Sihailongwan data or any other cited data allow for the sound assumption of an intensified East Asian summer monsoon in northeastern China during the Younger Dryas. The Late Glacial variability of the fen data found by can be easily explained by changes in the plant assemblage down core and thus by the composition of the peat. Furthermore, the use of bulk peat cellulose δ13C data as a precipitation proxy remains unproven for that area. Hence, there is no basis for a model contrasting Indian and East Asian summer monsoons during that period. [Copyright &y& Elsevier]

Abstract The soil organic carbon (SOC) and total nitrogen (TN) of topsoil could be greatly affected by the conversion of grassland to cropland (CGC) due to vegetation harvesting and soil erosion. However, few studies have evaluated the effects of these changes in the subsoil and distinguished its main controls at the regional scale. This paper investigated the total changes in the SOC stock (SOC S) and TN stock (TN S) of soils from 0 to 30 cm and 0–100 cm in depth over the past three decades in the Songnen Plain, China, a typical Mollisol region. The CGC resulted in a moderate loss of topsoil C and N but an increase in subsoil C and N, and the soil mapping results showed that approximately 7.47 × 1011 kg C and 1.51 × 1011 kg N were accumulated during the past three decades. Prediction uncertainty was assessed by 100 model runs with random jackknife partitions, and high uncertainty was found in the areas with rapidly changing SOC S and TN S levels. Our findings indicated that subsoil should be considered in the estimation of the SOC S and TN S at the regional scale. The SOC S and TN S of the CGC areas were anticipated to increase after long-term cultivation. In view of ongoing cropland expansion, up-to-date land use and soil type data are vital for selecting monitoring sites and understanding long-term soil evolution at the regional scale. Highlights • Conversion of grassland to cropland led to a moderate loss of topsoil C and N, but an increase in C and N in subsoil. • Subsoil should be considered for the estimation of SOC and TN stocks at the regional scale. • The SOC and TN stocks of recent cultivated soils were anticipated to increase after a long term cultivation. [ABSTRACT FROM AUTHOR]

Even after the Russo-Japanese War, Manchuria remained the powder keg of East Asia. In the war’s aftermath, three empires, the Qing, the Russian and the Japanese, stationed their troops in Manchuria, in a struggle for military supremacy there. There has already been a considerable amount of research on these military activities. However, previous works have not discussed them from a triangular relationship. This paper contends that the history of modern East Asia cannot be understood until one examines the shift in the military balance in Manchuria from a triangular comparative point of view. The results of such examination show that, in Manchuria, each empire was unable to establish military domination alone, and therefore needed an alliance partner. During the Xinhai Revolution, the Russia-Japan ‘alliance’ wielded overwhelming military power against China. However, after the Russian Revolution in 1917, Japan renounced cooperation with a weakened Russia and built a new partnership with China to advance the Siberian intervention. The military triangle of Russia, China and Japan was unable to create a comprehensive regional security system in Manchuria because what was established was based on mutual distrust and fear. [ABSTRACT FROM AUTHOR]

This paper aims to examine the spread of Manchurian plague and the response of the Japanese colonial government. Previous studies of this issue stressed the successful, albeit forced, preventative measures taken by the Japanese colonial government. However, this paper argues that Western powers did not agree with the new theory that pneumonic plague was transmitted through respiratory infections, as discovered by Wu Liande and promoted by Kitasato Shibasaburo. They continued to believe the old Japanese theory that the plague was transmitted through fleas from rodents. The Japanese colonial government focused on reducing the rat population to prevent the spread of plague. Moreover, they had no quarantine hospitals or other equipment, and epidemic prevention programs and measures were inadequate. The success of their efforts was due less to the measures taken by the Japanese colonial government than from the low influx of Chinese laborers into Korea. [ABSTRACT FROM AUTHOR]

In the study, we analyze and assess quantitatively the spatial pattern of vegetation and its ecological degradation information in the Honghe National Nature Reserve (HNNR), a Ramsar-designated site in Northeast China. Statistics from historical survey data are used to measure the degradation of marshes over time and changes in the hydrological regime. Long-term statistical data are also employed to analyze both natural and human impacts on these changes. Both the wetland degradation model and its mechanisms are discussed in this paper. The research finds that the loss of water and other types of degradation in the vegetation habitat caused by the rapid deterioration of the hydrological regime has threatened the status of HNNR as a “storage area of natural genes.” Scientifically constructed strategies are urgently required to ensure sustainable economic benefits that do not adversely affect this nature reserve. [ABSTRACT FROM AUTHOR]

The Songhua Lake in the Northeast China is chosen as a study case in this paper. Monitoring of samples and analysis 18 indexes related to the eutrophication in the Songhua Lake had been conducted in 2002–2004. Ecological risk assessment methods are employed here. The study results showed that total phosphorus and total nitrogen were main risk factors to impact on the eutrophication of the Songhua Lake, and influence of the phosphorus on the lake eutrophication was larger than that of nitrogen. Algal growth potential test was also conducted to validate the results. High phosphorus and high nitrogen concentrations were mostly distributed in Huifahekou and Jiaohe sites of the Songhua Lake. Threshold values of total phosphorus, total nitrogen and Chl-a concentrations from dose-effective examination were 0.065 mg/L, 0.843 mg/L, and 11.90 μg/L, respectively. The probability of the eutrophication appeared in the Songhua Lake was 0.69, of them, risk-free type area was 19.21% of total lake area, slight risk type area was 30.10%, middle risk type area was 16.50%, heavy risk type area was 25.8%, hyper risk type area was 8.39%. In order to control the eutrophication in the Songhua Lake, maximum permission discharges of total phosphorus and total nitrogen to the lake would be 2,123.78, 7,018.82 t/a, respectively. [ABSTRACT FROM AUTHOR]

The libraries described and discussed in this article were formed, during the first half of the twentieth century, by readers of Russian in China, and in particular by the Russian-speaking community in Harbin, the centre of Russian settlement and emigration in Manchuria (presently North-east China). The article is a revised and augmented version of a paper presented at the panel on 'Russian Far Eastern Publications in Exile', VII World Congress of the International Council for Central and East European Studies (ICCEES) in Berlin, 29 July 2005. [ABSTRACT FROM AUTHOR]

The northernmost border of Japan's informal empire were the Mongol lands and Manchuria. For nearly a century this region lay on the borders between an expanding Russia and a retreating China and was a major area for Japanese ambitions on the Asian mainland. Japan's interest in the Mongol lands (including Manchuria) was spurred by general strategic, economic and ideological factors, and was justified by an academic discourse on geopolitics. Geo-political socialisation was carried out in respective areas and Mongol nationalism was drawn into these affairs. This paper examines the reasons for Japan's interest in these areas, and the arguments used to justify this expansionism. [ABSTRACT FROM AUTHOR]

NE China is the easternmost part of the Central Asian Orogenic Belt (CAOB). The area is distinguished by widespread occurrence of Phanerozoic granitic rocks. In the companion paper (Part I), we established the Jurassic ages (184–137 Ma) for three granitic plutons: Xinhuatun, Lamashan and Yiershi. We also used geochemical data to argue that these rocks are highly fractionated I-type granites. In this paper, we present Sr–Nd–O isotope data of the three plutons and 32 additional samples to delineate the nature of their source, to determine the proportion of mantle to crustal components in the generation of the voluminous granitoids and to discuss crustal growth in the Phanerozoic.Despite their difference in emplacement age, Sr–Nd isotopic analyses reveal that these Jurassic granites have common isotopic characteristics. They all have low initial 87Sr/86Sr ratios (0.7045±0.0015), positive ϵNd(T) values (+1.3 to +2.8), and young Sm–Nd model ages (720–840 Ma). These characteristics are indicative of juvenile nature for these granites. Other Late Paleozoic to Mesozoic granites in this region also show the same features. Sr–Nd and oxygen isotopic data suggest that the magmatic evolution of the granites can be explained in terms of two-stage processes: (1) formation of parental magmas by melting of a relatively juvenile crust, which is probably a mixed lithology formed by pre-existing lower crust intruded or underplated by mantle-derived basaltic magma, and (2) extensive magmatic differentiation of the parental magmas in a slow cooling environment.The widespread distribution of juvenile granitoids in NE China indicates a massive transfer of mantle material to the crust in a post-orogenic tectonic setting. Several recent studies have documented that juvenile granitoids of Paleozoic to Mesozoic ages are ubiquitous in the Central Asian Orogenic Belt, hence suggesting a significant growth of the continental crust in the Phanerozoic. [Copyright &y& Elsevier]

Globally, natural wetlands have suffered severe ecological degradation (vegetation, soil, and biotic community) due to multiple factors. Understanding the spatiotemporal dynamics and driving forces of natural wetlands is the key to natural wetlands' protection and regional restoration. In this study, we first investigated the spatiotemporal evolutionary trends and shifting characteristics of natural wetlands in the Northeast Plain of China from 1990 to 2020. A dataset of driving-force evaluation indicators was constructed with nine indirect (elevation, temperature, road network, etc.) and four direct influencing factors (dryland, paddy field, woodland, grassland). Finally, we built the driving force analysis model of natural wetlands changes to quantitatively refine the contribution of different driving factors for natural wetlands' dynamic change by introducing the sparrow search algorithm (SSA) and extreme gradient boosting algorithm (XGBoost). The results showed that the total area of natural wetlands in the Northeast Plain of China increased by 32% from 1990 to 2020, mainly showing a first decline and then an increasing trend. Combined with the results of transfer intensity, we found that the substantial turn-out phenomenon of natural wetlands occurred in 2000–2005 and was mainly concentrated in the central and eastern parts of the Northeast Plain, while the substantial turn-in phenomenon of 2005–2010 was mainly located in the northeast of the study area. Compared with a traditional regression model, the SSA-XGBoost model not only weakened the multicollinearity of each driver but also significantly improved the generalization ability and interpretability of the model. The coefficient of determination (R2) of the SSA-XGBoost model exceeded 0.6 in both the natural wetland decline and rise cycles, which could effectively quantify the contribution of each driving factor. From the results of the model calculations, agricultural activities consisting of dryland and paddy fields during the entire cycle of natural wetland change were the main driving factors, with relative contributions of 18.59% and 15.40%, respectively. Both meteorological (temperature, precipitation) and topographic factors (elevation, slope) had a driving role in the spatiotemporal variation of natural wetlands. The gross domestic product (GDP) had the lowest contribution to natural wetlands' variation. This study provides a new method of quantitative analysis based on machine learning theory for determining the causes of natural wetland changes; it can be applied to large spatial scale areas, which is essential for a rapid monitoring of natural wetlands' resources and an accurate decision-making on the ecological environment's security. [ABSTRACT FROM AUTHOR]

During the initial period of straw return, a suitable straw return technology can lay the foundation for long-term soil fertility improvement. This study focused on the issues of backward straw return technology and blind fertilizer application in the southern part of the maize-producing area in the Northeast Plain of China. In this study, two straw return modes (2-year no-tillage straw cover + 1-year deep loosening and burying straw returning mode, NPT; 3-year rotary tillage and burying straw returning mode, RT), with RT mode as a control, were combined with different N fertilizer application rates (0, 192, 240 kg/ha). The changes in soil organic carbon (SOC) and its active components (MBC, DOC, and LOC) in the 0–40 cm soil layer were analyzed, and the carbon stratification rate, carbon pool index (CPI), SOC storages of each component, and maize yield were calculated to evaluate the short-term (3-year) differences in soil organic carbon quantity and quality in order to find suitable straw return methods and nitrogen application rate combinations. The results showed that the NPT mode increased the SOC and MBC content in the 20–30 cm soil layer, with an increase of 16.2% to 37.8% and 23.0% to 50.3%, respectively, compared with the RT mode. Under the NPT mode, the carbon pool stability was higher after nitrogen fertilizer addition, with a CPI value of 10.2% to 37.8% higher in the 20–40 cm soil layer compared with the RT mode. The differences in maize yield were not significant (p < 0.05) between the nitrogen application rates of 192 kg/ha and 240 kg/ha, but the SOC storages did not show significant changes. The MBC storage had the highest value under the nitrogen application rate of 192 kg/ha. Therefore, we thought that, in the early stage of straw return, the organic carbon priming effect caused by increased microbial activity was higher under the nitrogen application rate of 192 kg/ha. Considering the aspects of not affecting maize yield and improving SOC stability, it is recommended to use the NPT mode with the application of a 240 kg/ha nitrogen fertilizer rate for straw return. [ABSTRACT FROM AUTHOR]

Straw bale buildings have the potential reduce the environmental impact of construction. Although the technique has been introduced into northern China more than a decade ago, the construction method and potential problems within straw bale walls have not been fully understood in existing research. Following an analysis of existing straw bale construction both in north China and worldwide, this paper proposes modifications to the straw bale construction details currently used in north China. The modifications involve in-fill raw material, toe-up design and lime render application. These modifications were incorporated into an experimental building constructed in north China, and after having been monitored for 12 months, the modified construction details were critically assessed. The data demonstrate that rice straw bale walls are resistant to agents of decay and offer reduced construction time and cost than standard wall construction in north China. The construction method has the potential to become a mature construction system in the Chinese market in the future offering significant benefits both in construction and operational cost and in environmental impact. [ABSTRACT FROM AUTHOR]

The space P and space L representation models are often adopted together in the empirical analysis of bus transport networks (BTNs). In this paper, we develop a new representation model for BTNs using double edge weights and node weights, namely perfect space P. The model incorporates the number and lengths of directed routes between the two stations and the number of routes that connect to each station. Based on the model, we develop an empirical study on four large BTNs in Northeast China. Some common network characteristics of the BTNs are revealed and discussed in detail. The results show that several empirical distributions follow an exponential law. Moreover, the unweighted path length distributions can be fitted by a Gaussian function, while the weighted path length distributions can be fitted by a composite Gaussian function. Specifically, we introduce the weighted-degree distribution with different lengths and the special edge weight distribution, given the new evidence for the random behavior during the expansion of BTNs, including new stations and routes. [ABSTRACT FROM AUTHOR]

The increasing severity and intensity of harmful algal blooms (HABs) are of great concern to public health and a threat to ecosystems and have become a global problem in recent decades. Most of the related studies in China have been focused on low-latitude areas, such as Lake Taihu, Chaohu, and Dianchi. However, little attention has been devoted to algal blooms in Northeast China. As a significant Chinese commodity grain production base, the non-point source pollution deteriorated along with the grain production increasing year by year. In fact, the HABs in the little researched Northeast China were exceedingly serious. From 1982 to 2016, there was a total of 271 out of 2186 feasible Landsat images found HABs. The annual total frequencies of the detected HABs increased in fluctuation from 0 in 1982 to 11 times in 2016, and the highest frequency was observed twice, in 2010 and 2014, and was 29 times in both years. The number of lakes and reservoirs detected HABs and the annual sum of normalized HABs area also increased obviously. The tendency was almost coherent with the rising temperature, reduced wind speed, and declining atmospheric pressure. The R 2 and p-value between the annual frequency and the three meteorological indices were (0.274, <0.005), (0.553, <0.0001), and (0.073, 0.126), respectively. Besides, as anthropogenic influence indicators in this paper, we selected fertilizer application amount, industrial wastewater and municipal sewage discharge amount, land use type in 1986, 2000, and 2010. We comprehensively considered lacustrine morphologies and hydrological hydrodynamics and analyzed the driving factors of the spatiotemporal distribution pattern of HABs in Northeast China. [ABSTRACT FROM AUTHOR]

Recent studies on regional haze pollution over China come up in general with strong variability of main causes of heavy polluted episodes, in linkage with local specificities, sources and pollution characteristics. This paper therefore aims at elucidating the main specific sources and formation mechanisms of observed strong haze pollution episodes over 1–15 November 2015 in Northeast region considered as one of biggest megacity clusters in China. The Northeast China mega-city cluster, including Heilong Jiang, Jilin and Liaoning provinces, is adjacent to Russia in the north, Mongolian at the west, North Korea at east, and representing key geographical location in the regional and transnational air pollution issues in China due to the presence of heavy industries and intense economic activities. The present study, based on air quality monitoring, remote sensing satellite data and sensitivity experiments carried on the Nested Air Quality Prediction Modeling System (NAQPMS), quantitatively assesses the impact of meteorological conditions and potential contributions from regional chemical transport, intensive energy combustion, illegal emission and biomass burning emissions to PM 2.5 concentration variation. The results indicate strong inversion occurrence at lower atmosphere with weak near-surface wind speed and high relative humidity, leading to PM 2.5 concentration increase of about 30–50%. Intensive energy combustion (plausibly for heating activities) and illegal emission also significantly enhance the overall PM 2.5 accumulation by 100–200 μg m −3 (60–70% increase), against 75–100 μg m −3 from the biomass burning under the northeast-southwest transport pathway, corresponding to a contribution of 10–20% to PM 2.5 concentration increase. Obviously, stagnant meteorological conditions, energy combustion, illegal emission and biomass burning are main drivers of strong haze formation and spatial distribution over Northeast China megacity cluster. In clear, much effort on emission abatement at both local and regional scales is still an urgent imperative to overcome current critical haze pollution. [ABSTRACT FROM AUTHOR]

Since the economic reforms launched at the end of the 1970s, China has experienced dramatic socioeconomic change which has led to the emergence of new and distinctive regions of economic interaction characterised by an extensive and intensive mix of agricultural and non-agricultural activities. This paper illustrates the nature and characteristics of these evolving Extended Metropolitan Regions (EMRs) by drawing on the experience of the Shenyang-Dalian urban corridor in Northeast China (Manchuria). The increased level of economic interaction between the cities and the countryside is characterised by accelerated labour and capital flows, rapidly expanding rural-urban commodity trade and subcontracting between urban and rural enterprises. The result is a rapid erosion of differences in the standard of living, economic function and life style between the city and the countryside. [ABSTRACT FROM AUTHOR]

Simple Summary: The phenomenon of global climate change can impact the geographic range and abundance of species, thereby heightening the vulnerability of rare species to extinction. The reed parrotbill (Paradoxornis heudei David, 1872) is endemic to central and eastern China and is considered a near-threatened species according to the International Union for Conservation of Nature (IUCN). This study shows that temperature annual range, annual precipitation, and isothermality were the principal climatic factors to limit the habitat suitability of P. heudei. Presently, the suitable habitat for P. heudei is predominantly found in the central–eastern and northeast plains of China, especially the eastern coastal area. P. heudei is sensitive to climate change. In the future, northeastern China may serve as a potential suitable habitat for P. heudei. The phenomenon of global climate change can impact the geographic range and biodiversity, thereby heightening the vulnerability of rare species to extinction. The reed parrotbill (Paradoxornis heudei David, 1872) is endemic to central and eastern China, it is mainly distributed in the middle and lower reaches of the Yangtze River Plain and the Northeast Plain. In this study, eight of ten algorithms of the species distribution model (SDM) were used to evaluate the impact of climate change on the potential distribution of P. heudei under current and future climate scenarios and to analyze the possible related climate factors. After checking the collected data, 97 occurrence records of P. heudei were used. The relative contribution rate shows that among the selected climatic variables, temperature annual range (bio7), annual precipitation (bio12), and isothermality (bio3) were the principal climatic factors to limit the habitat suitability of P. heudei. The suitable habitat for P. heudei is primarily concentrated in the central–eastern and northeast plains of China, particularly in the eastern coastal region, spanning a mere area of 57,841 km2. The habitat suitability of P. heudei under different representative concentration pathway (RCP) scenarios was predicted to be different under future climatic conditions, but all of them had a larger range than the current one. The species distribution range could expand by more than 100% on average compared with the current range under the four scenarios in 2050, while it could contract by approximately 30% on average relative to the 2050 range in 2070 under different climate change scenarios. In the future, northeastern China may serve as a potential suitable habitat for P. heudei. The changes in the spatial and temporal distributions of P. heudei's range are of utmost importance in identifying high-priority conservation regions and devising effective management strategies for its preservation. [ABSTRACT FROM AUTHOR]

Urban village collectives, as one of the stakeholders of land requisition and development in urbanized China, have gradually been driven into real estate development. This transformation has raised an important question regarding how villagers develop their 'property mind'. From 2015 to 2017, guided by an abductive institutional economics approach, which holds both original and new institutional economics in dialogue, we addressed this question by conducting fieldwork in Xiaojia village, Northeast China. In Northeast China, unlike in the southern cities, there was no foreign investment and the population was in decline. Nevertheless, the villagers developed housing, first for their own use and then for the market. The resulting evidence indicates the following: 1) property rights are social relations and constructed socially and institutionally; 2) markets are not independent, they are conditioned by the institutional context. [ABSTRACT FROM AUTHOR]

Analyzing spatiotemporal dynamics of land use and land cover over time is widely recognized as important to better understand and provide solutions for social, economic, and environmental problems, especially in ecologically fragile region. In this paper, a case study was taken in Zhenlai County, which is a part of farming-pastoral ecotone of Northeast China. This study seeks to use multi-temporal satellite images and other data from various sources to analyze spatiotemporal changes from 1932 to 2005, and applied a quantitative methodology named intensity analysis in the time scale of decades at three levels: time interval, category, and transition. The findings of the case study are as follows: 1) the interval level of intensity analysis revealed that the annual rate of overall change was relatively fast in 1932-1954 and 1954-1976 time intervals. 2) The category level showed that arable land experienced less intensively gains and losses if the overall change was to have been distributed uniformly across the landscape while the gains and losses of forest land, grassland, water, settlement, wetland and other unused land were not consistent and stationary across the four time intervals. 3) The transition level illustrated that arable land expanded at the expense of grassland before 2000 while it gained intensively from wetland from 2000 to 2005. Settlement targets arable land and avoids grassland, water, wetland and other unused land. Besides, the loss of grassland was intensively targeted by arable land, forest land and wetland in the study period while the loss of wetland was targeted by water except for the time interval of 1976-2000. 4) During the early reclamation period, land use change of the study area was mainly affected by the policy, institutional and political factors, followed by the natural disasters. [ABSTRACT FROM AUTHOR]

This paper develops a conceptual model and an indicator system for measuring economic resilience of resource-based cities based on the theory of evolutionary resilience and the related concepts of persistence, adaptation, and transformation. Nineteen resource- based cities in Northeast China were analyzed using the indicator system. The results showed that Liaoning and Jilin provinces had higher economic resilience than Heilongjiang Province. Panjin, Benxi, and Anshan in Liaoning Province were the top three cities, while Shuangyashan and other coal-based cities in Heilongjiang Province ranked last. Metals- and petroleum-based cities had significantly higher resilience than coal-based cities. The differences in persistence, adaptability, transformation, and resilience among resource-based cities decreased since the introduction of the Northeast Revitalization Strategy in 2003. Forestry-based cities improved the most in terms of resilience, followed by metals-based and multiple-resource cities; however, resilience dropped for coal-based cities, and petroleum-based cities falling the most. The findings illustrate the importance and the way to develop a differentiated approach to improve resilience among resource-based cities. [ABSTRACT FROM AUTHOR]

Due to the frequent irrigation and excessive fertilization during the rice production in China, diffuse nitrogen (N) and phosphorus (P) pollution from paddy fields has become a serious environment problem and poses great challenges to national water and food security. Considering the regional heterogeneities of climate, cultivation types and cropping systems of rice planting, many water management strategies have been proposed and implemented to control diffuse N and P pollution. However, the water management optimization at different scales (the field scale, the watershed scale and national scale) is lack of comprehensive analyzed. Here, this paper summarized the characteristics of frequent-used water managements and recommended the optimal water managements after identifying the critical risk periods of diffuse N and P runoff losses at the field scale. The effects of water management optimization on diffuse N and P pollution control at the watershed and national scale were also synthetically reviewed. The results indicated that optimized field water management decreased irrigation water use (38.7–40.0%) and reduced diffuse pollution (25.5–38.8%) without significantly compromising rice yield security (−4.20 to 6.5%). The critical risk periods of diffuse pollution were pre-flooding in the Northeast Plain, pre-flooding, regreening stage for transplanting rice (the seeding-three leaf stage for direct seeding rice) and within 2 weeks after topdressing fertilization in the Yangtze River Basin and Southeast Coast in China. The corresponding water managements for these periods has been proposed after considering the climate, precipitation and fertilization characteristics. Ditches and ponds intercepted water and nutrients and mitigated 6.0–39.0% N and P runoff losses in paddy field watersheds. Furthermore, the extensive implementation of paddy water management optimization (paddy fields, ditches and ponds) combined with other advanced agricultural measures, for example, fertilization optimization, would decrease diffuse N and P pollution by 40.7–80.8% at the watershed scale and 44.7–88.1% at the national scale, respectively. This research provided great insights into the specific characteristics of paddy water managements from the fields, watershed and national scale, proposed optimal water management strategies for the realization of sustainable rice production in China, and also summarized the emerging development trends for future research directions. [Display omitted] • Optimal paddy water managements at field, watershed and national scales were analyzed. • Optimal water managements were proposed for critical risk periods at field scale. • Future emerging prospects of paddy water managements from different scales were proposed. [ABSTRACT FROM AUTHOR]

Objectives: The conducted search reveals that Juglans mandshurica Maximowicz, called Manchuria walnuts, had many local uses that can be categorized into cancer, dermatosis and acesodyne. Key findings: Various metabolites including diarylheptanoids, naphthoquinones, and flavonoids (also their glycosides) were reported as bioactive metabolites. The isolated metabolites and extracts from J. mandshurica showed different biological activity including cytotoxicity, anti-inflammation, antimelanotic, anticomplement, anti-HIV, antimicrobial and anti-obesity activity. Summary: It is indicated that this review will add value to more scientific research on J. mandshurica and enhance the increased interest in the sustainable commercialization of J. mandshurica. It also leads to the validation of unverified ethnobotanical claims. Future studies on J. mandshurica would be focused to establish the links between the pharmacological activity, bioactive metabolites, and traditional uses. [ABSTRACT FROM AUTHOR]

Forest soil carbon is a major carbon pool of terrestrial ecosystems, and accurate estimation of soil organic carbon (SOC) stocks in forest ecosystems is rather challenging. This study compared the prediction performance of three empirical model approaches namely, regression kriging (RK), multiple stepwise regression (MSR), random forest (RF), and boosted regression trees (BRT) to predict SOC stocks in Northeast China for 1990 and 2015. Furthermore, the spatial variation of SOC stocks and the main controlling environmental factors during the past 25 years were identified. A total of 82 (in 1990) and 157 (in 2015) topsoil (0-20 cm) samples with 12 environmental factors (soil property, climate, topography and biology) were selected for model construction. Randomly selected 80% of the soil sample data were used to train the models and the other 20% data for model verification using mean absolute error, root mean square error, coefficient of determination and Lin's consistency correlation coefficient indices. We found BRT model as the best prediction model and it could explain 67% and 60% spatial variation of SOC stocks, in 1990, and 2015, respectively. Predicted maps of all models in both periods showed similar spatial distribution characteristics, with the lower SOC in northeast and higher SOC in southwest. Mean annual temperature and elevation were the key environmental factors influencing the spatial variation of SOC stock in both periods. SOC stocks were mainly stored under Cambosols, Gleyosols and Isohumosols, accounting for 95.6% (1990) and 95.9% (2015). Overall, SOC stocks increased by 471 Tg C during the past 25 years. Our study found that the BRT model employing common environmental factors was the most robust method for forest topsoil SOC stocks inventories. The spatial resolution of BRT model enabled us to pinpoint in which areas of Northeast China that new forest tree planting would be most effective for enhancing forest C stocks. Overall, our approach is likely to be useful in forestry management and ecological restoration at and beyond the regional scale. [ABSTRACT FROM AUTHOR]

In the semiarid sandy region of Northeast China, Mongolian pine (Pinus sylvestris var. mongolica) suffers dieback after the age of 35, while Japanese red pine (Pinus densiflora) and Chinese pine (Pinus tabuliformis) stay healthy. Foliar nutrient retranslocation reflects the nutrient conservation and utilization mechanism of plants in response to their habitats. However, the nutrient retranslocation strategies employed by three Pinus tree species to cope with nutrient limitations remain largely unknown. For this study, we investigated the seasonal variations in nitrogen (N) and phosphorus (P) concentrations of Mongolian pine, Japanese red pine, and Chinese pine plantations in terms of the green needles of all ages, senesced needles, and soil. Further, the N retranslocation efficiency (NRE), and P retranslocation efficiency (PRE), and correlations between the N:P ratios of needles and soil were analyzed. The results showed that, except for the spring NRE in 1-year-old needles of Mongolian pine, the spring NRE and PRE in 1- and 2-year-old needles of the three tree species were greater than zero. The autumn PRE was higher than zero for Mongolian pine, but lower than zero for Japanese red pine and Chinese pine. Among the three Pinus species, Mongolian pine showed greater spring PRE in 2-year-old needles, and PRE from 1- to 2-yearold needles, and from 2-year-old needles to litter. However, Japanese red pine had higher P concentrations and lower N:P ratios in senesced needles, while greater PRE was found in Chinese pine litter. Significant relationships between the N:P ratios were found in the current year and 1-year-old needles and soil in the Mongolian pine plantation, while there was an insignificant relationship between the N:P ratios of the needles and soil in the Chinese pine plantation. Thus, for Mongolian pine, the removal of P from needles in autumn, and higher P translocation from older needles under P-deficient soil may have contributed to the tree dieback. In contrast, Japanese red pine and Chinese pine stored P in their needles during autumn. Japanese red pine returned more P to the soil via litter, while Chinese pine maintained N:P homeostasis and increased P withdrawal prior to needle abscission. [ABSTRACT FROM AUTHOR]

The residual levels of 25 monitored pesticides in 6,229 brown rice samples obtained from the 17 provinces of the three main rice-growing regions in China during 2016–2020 were analyzed, and the cumulative risks of chronic and acute exposure to pesticides for the Chinese population were assessed. The QuEChERS extraction coupled with liquid chromatography-mass spectrometry for simultaneous determination of 25 pesticide residues in brown rice was developed and validated with good accuracy and precision (recoveries of 70%–120% and RSD ≤20%). The overall detection rate and over the maximum residue limit (MRL) rate of pesticides in brown rice decreased from 39.15% and 3.59% in 2016 to 34.11% and 1.53% in 2020, respectively. The Yangtze River basin had a higher detection rate and over MRL rate (43.14% and 2.88%, respectively) compared with the Southeast Coastal region (37.28% and 2.77%) and the Northeast Plain (11.28% and 0.17%). Isoprothiolane (13.57%) and carbendazim (8.32%) were the most frequently detected in rice samples. Pesticide residues exceeding the MRLs were found most often in triazophos (0.75%) and isocarbophos (0.51%). The risk ranking of pesticide residues based on the ranking matrix showed that carbofuran, methamidophos, and isocarbophos had the highest residual risk scores of 25.09, 25.01, and 25.00, respectively. 17.7% of rice samples contained two or more pesticide residues. The cumulative risk assessments based on the relative potency factor (RPF) approach revealed that the cumulative risks of chronic and acute dietary exposure to organophosphorus, neonicotinoid insecticides, and triazole fungicides from rice ranged from 7.43 × 10−4 to 3.36 × 10−2, which were not considered of health concern. The study provides national-scale information on the contamination levels and health risks of pesticide residues in rice, which can help develop continuous monitoring programs for pesticide residue contamination in rice in China. [ABSTRACT FROM AUTHOR]

The Paleozoic to early Mesozoic tectonic framework and evolution of Northeast China, especially the Jiamusi block and its related structural belts, are highly debated. In this paper, geochemical, geochronological and isotopic analyses were carried out on the blueschist in the Heilongjiang Complex to address these issues. The Heilongjiang Complex defines the suture belt between the Jiamusi block and the Songliao block in NE China, and the blueschist is a major composition for this complex, coexisting with mafic-ultramafic rocks, greenschist, quartzite and mica schist. The blueschist has a mineral association of sodic amphibole, epidote, chlorite, phengite, albite and quartz with accessory phases of apatite, titanite, zircon and ilmenite. Together with the lithological association, the major and trace element compositions present that the protoliths of the blueschist can be divided into the alkaline and tholeiitic basalts and have OIB affinities, formed in an ocean island setting, indicated by the (La/Yb) N values of 3.57 – 11.54, and the (La/Sm) N values of 0.69 – 3.64. The high and positive ε Nd (t) values of + 3.7 to + 9.0, and relative enrichment in Nb (vs. Th) and Ta (vs. U) show that both the alkaline and tholeiitic basalts may be derived from the asthenospheric mantle with insignificant crustal contamination. Magmatic zircons from the blueschist in Yilan area yield a 206 Pb/ 238 U age of 281 ± 3 Ma, interpreted as its protolithic age. The youngest ages of ~ 200 Ma of the detrital zircons in the associated mica schist from Mudanjiang area place constraints on the timing of metamorphism for the blueschist. These indicate that a big ocean existed between the Jiamusi and Songliao blocks at least since the early Permian, and the blueschist formed since the late Triassic to late Jurassic by the subduction of this ocean. Such an ocean during the Permian – Jurassic is difficult to be interpreted by the tectonic evolution of the Paleo-Asian Ocean. [ABSTRACT FROM AUTHOR]

A gathering pipeline in a gas field in Northeast China transporting mainly natural gas and also some water and sands was welded using two 20G pipes with different wall thicknesses. The internal corrosion of this pipeline was inhomogeneous. The unequal wall thickness welded joint suffered more serious corrosion damage than did other parts of the pipe and was found to fail during routine maintenance. In this paper, the corrosion damage at this joint was studied based on inhomogeneity. Internal and external factors affecting corrosion, such as the mechanical and electrochemical properties of materials, stress distribution at the joint, and the flow condition in the pipe, and their combined action were investigated. Failure attribution was performed on this basis. Specifically, a hardness test was conducted on different zones of the joint, including the base metal (BM), heat-affected zone (HAZ) and weld metal (WM), to investigate the abrasive wear resistance at the joint. Microstructures of the three zones were characterized by optical microscopy. The morphology and composition of the corrosion film covering the inner surface of the welded joint were characterized by scanning electron microscopy (SEM), energy-dispersive spectroscopy (EDS) and X-ray powder diffraction (XRD). Potentiodynamic polarization experiments and electrochemical impedance spectroscopy (EIS) were conducted on samples from the three zones to investigate their electrochemical performances. Moreover, a computational fluid dynamics (CFD) analysis was performed to obtain the flow condition near the joint, and a finite element method (FEM) was used to calculate the stress distribution at the joint. The results showed that the internal corrosion mechanism of the pipeline was CO 2 corrosion accelerated by detrimental Cl − . The geometric discontinuity of the welded joint was the main cause of the accelerated corrosion damage at the joint. The change in wall thickness of the welded pipe not only produced gas vortices but also led to stress concentration. Both of these conditions can further accelerate corrosion by destroying the protectiveness of the corrosion film. It is suggested that the corrosion can be prevented by eliminating the inhomogeneities of fluid flow and stress distribution. [ABSTRACT FROM AUTHOR]

In this paper, a trace-transform-based radial trace time frequency peak-filtering method (RT-TFPF) with temporal-spatial directions is proposed. It utilizes the similarity of data along the reflection event and computes the temporal–spatial radial directions by seeking the local maximum value of a constructed trace function. This method takes advantage of the TFPF in non-stationary signal estimation, especially with no prior knowledge. Furthermore, applying the filtering in the temporal–spatial domain results in less biased TFPF estimation. Within the framework of the trace transform, the specified trace function first calculates the centroid and then accumulates the energy of the reflected signal along the trajectory, helping to find the locally optimal filtering directions automatically. Experiments on both synthetic record and field data in North-East China demonstrates good performance–strong random noise can be attenuated, while at the same time, the estimated reflection signal is more accurate for use in interpretation. [ABSTRACT FROM AUTHOR]