Table of Content

15 December 2022, Volume 33 Issue 12

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Special Features of Industrial Ecology and Social Ecosystem Management

Data-driven study of complex socio-economic-natural ecosystems: Scales, processes and decision linkages

XUE Bing, LI Hong-qing, HUANG Bei-jia, WANG He-ming, ZHAO Xue-yan, FANG Kai, CHEN Cheng, CHEN Wei-qiang, SHI Lei, GOU Xiao-hua

2022, 33(12):  3169-3176.  doi:10.13287/j.1001-9332.202212.039

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The social-economic-natural system is a complex system for human survival and development, and the data-driven system research provides a new value-added orientation to enhance the cognition of the ecosystem. Under the new data context, the social-economic-natural complex system shows new features. The research object is gradually changing from a single element to a multi-factor coupling direction, which makes the data system more diversified, data sources more extensive, data expression more visualized. The research scale shows the characteristics of gradually expanding, and the research object would be more detailed. In the process of data identification, expression and visualization, it is therefore necessary to strengthen the coupling of time, space, structure, quantity and order, as well as to focus on the integration with decision making and local services. The future research of complex ecosystems in the new era should be carried out in terms of key scientific issues and supporting technologies, the role of scale and multi-factor coupling, as well as scientific and technological support for local and global governance. Under the continuous innovation of data, strengthening the cognition of multi-source data, long-term monitoring and time series still needs to be studied in depth. Carrying out data-driven analysis of complex ecosystems not only provides technical support for ecosystem services and sustainable development and enhances the long-term data sharing mechanism, but also provides more value support for realizing decision making and information dissemination.

Approach and evidence-based study of provincial-level eco-economic development planning

HAN Bin, TANG Cheng-rui, REN Wan-xia, LIU Miao, FANG Yun-ting, XUE Bing

2022, 33(12):  3177-3185.  doi:10.13287/j.1001-9332.202212.023

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The development of ecological economy is one of the core elements of the ecological civilization system and an essential means to optimize the social-ecological systems. The key to developing ecological economy lies in preparing the development plan to realize concrete implementation. Given the objective and realistic demand for the development of ecological economy, it is critically needed to propose the approach of eco-economic planning and conduct empirical research. We sorted out the connotation of ecological economy, proposed the general idea of “object identification-resource evaluation-principal construction-target setting-task content-mechanism guarantee”, and proposed three work modules, including “preliminary preparation, content design, review & approval”, and finally built a technical system for the preparation of provincial-scale ecological economy planning. We outlined the 14th Five-Year Plan for Eco-Economic Development of Liaoning Province, and discussed critical issues such as the connotation definition and index system establishment for eco-economic development plan. This work provides ideas for the scientific and standardized preparation of ecological economy development plan at the provincial level in China.

Socio-economic metabolism research: Connotation, discovery, and prospect

CHEN Wei-qiang, SONG Lu-lu, WANG He-ming, SHI Lei

2022, 33(12):  3186-3194.  doi:10.13287/j.1001-9332.202212.021

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Socio-economic metabolism refers to the human-driven migration and transformation of material and energy within and at the boundary of the socio-economic system. The research of socio-economic metabolism has become the core in industrial ecology. We introduced the connotation and basic steps of socio-economic metabolism research with typical cases, and summarized the main findings of socio-economic metabolism research. The research provide a method and model to track the sources, sinks, and flow path of materials in the socio-economic system, reveal how materials and their socio-economic metabolic processes supported modern production and lifestyle. Related studies have clarified the mechanism by which human activities driving the ecological and environmental problems related to material metabolism. It provides the model and database for evaluating the resource efficiency, the trend of resource supply and demand, and the potential of urban mining. We put forward the future directions of socio-economic metabolism research: to increase research objects and enhance the research precision of each object; to expand and deepen the temporal and spatial boundaries of the research system; to introduce and integrate new data sources and research methods; to connect the material flows of socio-economic metabolism with its related ecological and environmental impacts; and to establish a data platform that could be shared, expanded and accumulated.

Governance mechanisms of industrial carbon emissions in heavy industrial zones under environmental justice based on evolutionary game perspective

WANG Yue, ZENG Xian

2022, 33(12):  3195-3204.  doi:10.13287/j.1001-9332.202212.020

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Exploring the governance mechanisms of industrial carbon emissions in heavy industrial zones under the background of ecological civilization construction is of great significance to achieve the goal of ‘double carbon' and environmental justice. With Liaoning heavy industrial zones as an example, we constructed a tripartite evolutionary game model of local government, industrial enterprises and third-party verification institutions. We examined the key factors affecting the strategic choice of industrial carbon emission tripartite stakeholders. The strategic choices of three stakeholders under different equilibrium points were simulated, and the industrial carbon emission governance mechanisms were constructed. The results showed that the stakeholder strategy choices of industrial carbon emissions under different equilibrium circumstances in the study area were in line with the reality and ideal respectively. In different equilibrium situations of tripartite stakeholder game, local governments, and third-party verification institutions played a leading role in the strategic choices of carbon emissions in different stable equilibrium circumstances. Policy subsidies, fines for violations, emission reduction costs, verification costs and regulatory costs were the key factors influencing the evolutionary game among the three stakeholders of industrial carbon emissions in the study area. Combined with the key influencing factors of industrial carbon emissions, the governance mechanisms of industrial carbon emissions in the study area were constructed from four aspects: innovation mechanism, constraint mechanism, market mechanism, and reverse forcing mechanism. Improving the balanced distribution of industrial carbon emission benefits in the study area amd promoting cooperation among the three parties would help realize environmental justice under the game of industrial carbon emission stakeholders.

Evaluation of sustainable intensification in agriculture: Research progress and prospects

LYU Xiao, XIN Zong-fei, PENG Wen-long, NIU Shan-dong

2022, 33(12):  3205-3212.  doi:10.13287/j.1001-9332.202212.019

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Sustainable intensification in agriculture (SI) is a realistic pathway to ensure global food security and deal with famine, poverty, and climate change. We constructed a SI research framework using methods such as literature, induction, and deduction. We reviewed the progress of SI research from four aspects, including the conceptual origin, index system, research scale, and evaluation methods. We discussed the future development path to provide reference for deepening related research of SI and its relation from the multi-disciplinary angle. There are many kinds of research on SI across the world, which give rich connotations to SI based on multiple dimensions of productivity, economy, environment, and society. The evaluation of SI involves productivity, economy, environment, human and society. It has formed a comprehensive evaluation system such as material input, resource productivity, environmental and economic efficiency, and other multiple indicators. Moreover, the evaluation methods of SI mainly include the factor comprehensive evaluation method and index model evaluation method. Studies on SI are not abundant in China, which needs to be enriched. We should break through the constraints of traditional theoretical and methodological frameworks, focus on the transformative scientific issues brought by international development, and explore the research paradigm of SI from the cross-disciplinary perspective.

Review on the assessment model of nutrient recycling with agricultural residues treatment technologies

YANG Zheng, LI Hong-qing, ZHAI Jia-ning, ZHANG Li-hua, NAN Qiong

2022, 33(12):  3213-3219.  doi:10.13287/j.1001-9332.202212.022

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The technology for nutrient resource utilization of agricultural residues is crucial to realizing a circular agricultural economy. The assessment model provides essential support to optimize nutrient recovery and treatment technologies. We specifically summarized research progress in the assessment framework of agricultural residues nutrient recycling technology, assessment models and evaluation indicators, data sources of models and their uncertainty analysis, and the application scale of models. We found that process mathematical models and industrial eco-logy models are the common nutrient flow assessment models. Process mathematical and industrial ecology models differed greatly in terms of the reliability of assessment results and the simulation scale. The former mainly focused at laboratory or pilot scale, with higher accuracy. The latter could achieve multi-scale simulation from microscopic to macroscopic and had higher uncertainty, due to the way its data were obtained. Finally, we provided an outlook on the research on the assessment model of agricultural residues nutrient resource utilisation technology. In order to achieve accurate assessment of waste resource utilisation technology in agricultural production systems at the regional scale, a reliable model framework and database should be established by combining process mathematical models with industrial ecology models. Meanwhile, we should carry out research on model expansion at the geographical scales of factory scale, farm scale, village scale, township scale, and regional scale.

Original Articles

Effects of warming, photoperiod, and nitrogen addition on the main phenological phases of Quercus mongolica

MA Cheng-xiang, ZHOU Guang-sheng, SONG Xing-yang, LYU Xiao-min

2022, 33(12):  3220-3228.  doi:10.13287/j.1001-9332.202212.005

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With a large artificial climate chamber, we examined the effects of warming (control, +1.5 ℃, +2.0 ℃), photoperiod (10, 14, 18 h) and nitrogen addition (0, 5, 10, 20 g N·m^-2·a^-1) on the main phenological phases of Quercus mongolica in Northeast China. The results showed that 1.5 and 2.0 ℃ warming significantly advanced the bud swelling stage and delayed the leaf fully coloring stage, which prolonged the growing season. The extended days increased with the increases of warming range. Photoperiod significantly affected autumn phenology (leaf coloration onset stage, leaf coloration in general stage, leaf fully coloring stage). Compared with photoperiod of 14 h, short photoperiod (10 h) significantly delayed leaf coloration onset stage by 7.0 d, and prolonged the peak of growth season. Nitrogen addition significantly advanced the bud swelling stage, bud opening stage, first leaf unfolding stage and full leaf unfolding stage. The leaf fully coloring stage was significantly delayed by 9.5 d only at the high nitrogen level of 20 g N·m^-2·a^-1, indicating that high nitrogen addition prolonged the growing season of Q. mongolica. The synergistic effects of warming and high nitrogen addition (20 g N·m^-2·a^-1) significantly delayed the leaf fully coloring stage, which prolonged leaf coloration stage, and the synergistic effects of warming and short photoperiod, the synergistic effects of nitrogen addition and short photoperiod. The synergistic effects of warming, nitrogen addition and short photoperiod all significantly delayed the leaf coloration onset stage, which relatively prolonged the peak of growing season.

Relationships between tree functional traits and leaf nitrogen and phosphorus resorption efficiencies in subtropical young plantations

JU Wen, HUANG Zhi-qun, FU Yan-rong, WANG Tao, WANG Zhen-yu, YU Zai-peng

2022, 33(12):  3229-3236.  doi:10.13287/j.1001-9332.202212.007

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We examined the relationship between tree functional traits and leaf nitrogen and phosphorus resorption efficiencies across 29 species in 3-year-old pure plantations in subtropical China. The results showed that the average nitrogen (NRE) and phosphorus (PRE) resorption efficiencies in 29 young plantations were 50.5% and 57.3%, respectively. The average NRE of 22 arbuscular mycorrhizal (AM) tree species was 52.7%, significantly higher than that of the seven ectomycorrhizal (EM) tree species (45.1%). NRE was positively correlated with fine root tissue density across the 29 tree species. PRE was positively correlated with root diameter in the seven EM tree species. Functional traits of 22 AM tree species were not associated with NRE and PRE. Among all of the 29 tree species, mycorrhizal type, specific leaf area, fine root tissue density, leaf thickness, and the interaction effects of mycorrhizal type with leaf thickness explained 27% variation in NRE. Specific root length, fine root carbon content, fine root carbon to nitrogen ratio, mycorrhizal type, leaf carbon content, and the interaction effects of mycorrhizal type with leaf carbon content explained 35% variation in PRE. Root functional trait of subtropical species could predict nitrogen and phosphorus resorption efficiencies. The model with multiple functional traits could better reveal the relative importance of different biological factors on nutrient resorption efficiency.

Potential turnover differences of exogenous alanine in soils of typical forests in the Xiaoxing'an Mountains, China

HAO Jing, GUO Ya-fen, GAO Lei

2022, 33(12):  3237-3244.  doi:10.13287/j.1001-9332.202212.004

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Taking five typical forests (Betula platyphylla forest, Quercus mongolica forest, B. platyphylla + Pinus koraiensis + Acer mono mixed forest, P. koraiensis forest, and Larix olgensis forest) in Xiaoxing'an Mountains as test objects, we investigated the effects of forest types (broadleaved forest, mixed forest, and coniferous forest) and soil layers (0-10 cm, 10-20 cm, 20-30 cm) on the turnover of exogenous alanine. The results showed that the turnover of soil exogenous alanine varied across different forest types, with significant difference in time and profile. The turnover rate was the highest in the broadleaved forest, followed by the mixed forest, and the lowest in the coniferous forest, with the half-life being 2.6-4.2, 3.6-5.5, and 4.3-7.0 h, respectively. With increasing soil depth, the potential turnover rate of exogenous alanine decreased, the half-life became longer, and soil adsorption of alanine weakened. With the addition of exogenous alanine, the content of ammonium and nitrate significantly increased, with the former being increased by 83.8%-95.3%, 80.9%-94.6% and 73.7%-93.2%, and the latter being increased by 82.9%-94.7%, 82.3%-93.8% and 78.1%-92.5% in the broadleaved forest, mixed forest, and coniferous forest, respectively. The net ammoniation and nitrification rates increased sharply at first and then decreased slowly, which were both positive. Soil layer and forest type as well as their interaction significantly affected the turnover, half-life, ammoniation, and nitrification of exogenous alanine.

Responses of aboveground and belowground net primary productivity of ephemeral plants to extreme drought and extreme precipitation

SHAYAGULI·Jigeer, ZANG Yong-xin, YIN Ben-feng, ZHANG Shu-jun, MAMTIMIN·Sulayman, ZHANG Yuan-ming

2022, 33(12):  3245-3252.  doi:10.13287/j.1001-9332.202212.006

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To examine the effects of extreme drought event and extreme precipitation event on productivity of ephemeral plant, we experimentally reduced and increased growing season precipitation amounts by 65% across four slope positions and aspects along sand dunes in the southern edge of the Gurbantünggüt Desert. The results showed that extreme drought significantly reduced aboveground net primary productivity (ANPP) and belowground net primary productivity (BNPP) by 48.8% and 13.7%, respectively, and that extreme precipitation significantly increased ANPP and BNPP by 37.9% and 23.2%, respectively. The sensitivity of ANPP (0.26 and 0.21 g·m^-2·mm^-1) to extreme drought and extreme precipitation was significantly higher than that of BNPP (0.02 and 0.03 g·m^-2·mm^-1). In addition, ANPP (24.22 g·m^-2) and BNPP (5.77 g·m^-2) on the east side of sand dune were significantly increased by 29.7% and 71.7% compared with those on the west side. There was no significant difference in the sensitivity of ANPP and BNPP to precipitation change among different slope positions and aspects.

Quantification on driving forces for spatiotemporal evolution of precipitation-use efficiency of grassland across recent two decades in Otog Banner, Inner Mongolia, China

LIU Hui, SONG Xiao-yu, JIA Qiong, ZHU De-ming

2022, 33(12):  3253-3262.  doi:10.13287/j.1001-9332.202211.007

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Precipitation use efficiency (PUE) is an effective index to evaluate the relationship between grassland productivity and precipitation in arid and semi-arid regions. To explore the driving mechanism of climate change and human activities on grassland PUE, we used the improved CASA model to estimate net primary productivity (NPP) of grassland from 2001 to 2020 in Otog Banner, Inner Mongolia. The PUE was obtained combining with the spatial interpolation data of precipitation. The spatiotemporal evolution of PUE and its responses to the six climate factors were analyzed using simple and piecewise linear regression. A quantitative analysis method based on partial derivatives was used to quantitatively evaluate the relative contributions of climate change and human activities to PUE dynamics. The results showed that the annual average value of PUE was 0.748 g C·m^-2·mm^-1 in Otog Banner, and that the inter-annual fluctuation had a significant downward trend at a rate of 0.014 g C·m^-2·mm^-1·a^-1. Across the study area, PUE increased from west part to east part, and exhibited significant single-peak piecewise linear patterns along the growth gradients of temperature, precipitation, relative humidity, sunshine hours, and ET₀. There was a sustained and significant increase pattern of fast first and then slow along the wind speed gradient. 94.3% of the grassland in the study area showed a decrease trend in PUE, and 43.6% area showed severely decreased. This prominent decrease in PUE was co-driven by climate change and human activities, whose contributions were -1.162×10^-2 and -0.240×10^-2 g C·m^-2·mm^-1·a^-1, respectively. Climate change was the primary driving force and precipitation was the key climate driving factor for the decrease in PUE.

Effects of grazing on soil aggregate composition and stability in Stipa breviflora desert steppe

ZHANG Bin, ZHAO Tian-qi, HE Qi-shen, ZHENG Jia-hua, ZHAO Meng-li

2022, 33(12):  3263-3270.  doi:10.13287/j.1001-9332.202212.013

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Grazing, one of the main grassland utilization modes, has notable impacts on grassland ecosystem structure and functions. However, the effects of long-term grazing on soil aggregate composition and stability are poorly understood. Based on a long-term grazing experiment platform in Inner Mongolia Stipa breviflora desert steppe established in 2004, with treatements of no grazing (control), light, moderate, and heavy grazing intensities, we studied the changes of soil aggregate composition and stability under different grazing intensities. With the measurement of relevant soil physical and chemical characteristics, we explored the main factors that affecting the stability of soil aggregates. The results showed that grazing significantly altered soil aggregate composition. Compared with control, the content of large aggregates (0.25-2 mm) was unchanged in light grazing but significantly decreased in treatments with moderate and heavy grazing intensities. Heavy grazing significantly decreased the content of small aggregates (0.053-0.25 mm), while light and moderate grazing significantly increased that of microaggregates (<0.053 mm). Soil aggregate stability was maintained at a high level under light grazing, but significantly decreased under moderate and heavy grazing treatments. Soil aggregate stability was positively correlated with macroaggregate content but negatively correlated with microaggregate content. Soil pH, bulk density, organic carbon and other physicochemical indices jointly contributed to the changes of soil aggregate composition and hence affect soil aggregate stability. In conclusion, our results showed that appropriate grazing could maintain high level of soil aggregate stability in desert steppe.

Characteristics of grassland degradation and its relationship with climate factors on Qinghai-Tibetan Plateau, China

SHI Ming-ming, WANG Zhe, ZHOU Bing-rong, YANG Xin-guang, SUN Wei-jie

2022, 33(12):  3271-3278.  doi:10.13287/j.1001-9332.202212.002

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Understanding the distribution, characteristics, and changing trend and persistence of grassland degradation and revealing its mechanism on the Qinghai-Tibetan Plateau can provide scientific basis for effective grassland management and conservation. We selected grassland coverage as the remote sensing monitoring index to establish the remote sensing monitoring and evaluation index system of grassland degradation and evaluate grassland degradation during 2016 to 2020 on the Qinghai-Tibet Plateau. The changing trend and persistence of grassland coverage were analyzed using linear regression and Hurst index analysis on a long time series scale (1982-2020). The partial correlation analysis was used to examine the influence of climate on grassland degradation. The results showed that grassland degradation reached 24.3% during 2016 to 2020, which was mainly light and moderate degradation, and largely distributed in low altitude and high fractional vegetation cover areas. From 1982 to 2020, grassland coverage tended to increase in the north, west and southwest, and decreased in the east and center of the Qinghai-Tibetan Plateau. The Hurst index of grassland coverage was less than 0.5 in 98.1% of the total grassland, indicating grassland coverage showed negatively persistent. The partial correlation coefficient between grassland coverage and precipitation (0.096) was higher than that of temperature (-0.033). About 16.0% area was dominated by temperature, which was mainly distributed in the central and southeast. About 12.2% area was dominated by precipitation, which was distributed in the northeast and west of the Qinghai-Tibetan Plateau.

Comprehensive evaluation of soil quality of different land use types on the northeastern margin of the Qinghai-Tibet Plateau, China

JIANG Cong-ze, SHOU Na, GAO Wei, MA Ren-shi, SHEN Yu-ying, YANG Xian-long

2022, 33(12):  3279-3286.  doi:10.13287/j.1001-9332.202212.016

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Soil quality evaluation is an important prerequisite for the rational soil resource utilization. We collected soil samples from forest (n=9), grassland (n=18) and cropland (n=38) in Tianzhu County, Gansu Province, which is located on the northeastern edge of the Qinghai-Tibet Plateau. Soil quality was evaluated based on thirteen soil physical and chemical indicators, including soil bulk density, field capacity, and organic matter. A minimum data set (MDS) was constructed using principal component analysis and correlation analysis to establish a soil qua-lity evaluation index (SQI) system, which was used in the soil quality evaluation for the three land-use types. The results showed that total porosity, capillary porosity, field capacity, capillary water capacity, saturated water content, organic matter, total nitrogen and available potassium content were significantly higher in forest than those in grassland and cropland. The SQI system of forest was based on field capacity, organic matter, total nitrogen, available nitrogen, and available potassium, and the SQI ranged between 0.329 to 0.678, with a mean value of 0.481. Grassland SQI system was based on field capacity and available nitrogen, with the SQI ranging between 0.302 to 0.703 and a mean value of 0.469. Cropland SQI system was based on capillary water capacity, non-capillary porosity, available nitrogen, available phosphorus, and available potassium, and the SQI ranged from 0.337 to 0.616 with a mean value of 0.462. The most important barriers to soil quality improvement in forest, grassland, and cropland were available potassium, field capacity, and capillary water capacity, respectively. The MDS-based SQI enabled an accurate evaluation of soil quality across different land-use types in the study area, which was best in forest followed by grassland and cropland. The evaluation results would provide important reference for sustainable soil management in the local area.

Difference in soil water holding capacity and the influencing factors under different land use types in the alpine region of Tibet, China

WANG Ming-hui, HUANG Lai-ming, CHEN Cui-bai

2022, 33(12):  3287-3293.  doi:10.13287/j.1001-9332.202212.012

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To investigate the variation of soil water holding capacity under different land use types can provide scientific basis for evaluating the change characteristics and regulation mechanism of water conservation capacity in alpine ecosystems. We collected soil samples at different depth intervals (0-10, 10-20 and 20-30 cm) under three land use types (farmland, forest, and grassland) in Tibet alpine region to measure the maximum water holding capacity, capillary water holding capacity, field capacity, and basic soil physicochemical properties. The associated environmental factors (mean annual precipitation, normalized difference vegetation index, altitude, slope gradient and surface roughness) were extracted to analyze the change characteristics and influencing factors of soil water holding capacity under different land use types. The results showed that soil water holding capacity (the maximum water holding capacity, capillary water holding capacity, and field capacity) of farmland, forest, and grassland all decreased with increasing soil depth. The mean values of the maximum water holding capacity, capillary water holding capacity, and field capacity in the 0-30 cm soil layer of grassland were 379.79, 329.57 and 194.39 g·kg^-1, respectively, which were significantly higher than that of farmland (301.15, 259.67, and 154.91 g·kg^-1) and forest (293.09, 251.49, and 117.01 g·kg^-1). Results of the redundancy analysis showed that soil properties significantly influenced soil water holding capacity, with explanation rate of 44.6%, 42.7%, 37.6% and 35.8% for total porosity, soil organic matter, capillary porosity and soil bulk density, respectively. Results of the principal component analysis showed that mean annual precipitation, normalized difference vegetation index, altitude, slope gradient, and surface roughness were the main environmental factors affecting the spatial variation of soil water holding capacity, with a cumulative contribution of 72.4%. The grassland in the alpine region of Tibet had the highest water holding capacity and could effectively prevent soil erosion. Therefore, the implementation of returning farmland to grassland and the enclosure management of degraded grassland would be conducive to improve soil water conservation capacity in the alpine regions.

Latitudinal variations of seed functional traits of Phragmites australis in Chinese coastal marsh

WANG Hao-yu, TONG Chuan, HUANG Jia-fang, ZHANG Li-wen, QIU Guang-long, BU Ren-cang, LIANG Chang-e

2022, 33(12):  3294-3302.  doi:10.13287/j.1001-9332.202212.001

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Functional traits of seeds reflect plant reproductive strategies adapting to environmental changes, which is an evolutionary behavior in natural selection and genetics. Study on seed functional traits is of great significance to deeply understand the long-term adaptive evolution of plants and seeds. We measured seed functional traits of a main indigenous species Phragmites australis, including seed size, seed weight, seed set, and seed production, in nine coastal marshes of the six provinces/cities along the coastal zone of China (21°29′-40°57′ N), and analyzed latitudinal variations of functional traits. The results showed that seed functional traits of P. australis in Chinese coastal marshes varied significantly with latitude and that there were significant correlations among different traits. Seed size (including seed length, seed width, seed shape index, aspect ratio, and seed surface area), and 100-seed weight showed significant quadratic function relation with latitude, which firstly decreased and then increased with the increases of latitude, while seed setting rate firstly increased and then reduced. There was a trade-off between the number and size of P. australis seeds. Seed production per unit area significantly increased with latitude. Results of stepwise regression analysis showed that climatic factors were the main driver resulting in the difference of seed functional traits of P. australis between latitudes, followed by pH and salinity of soil porewater.

Ectomycorrhizal fungi enhance salt tolerance of Quercus mongolica by regulating ion balance

GUO Wei, HAO Han, ZHANG Wei-hao, HU Zeng-hui, LENG Ping-sheng

2022, 33(12):  3303-3311.  doi:10.13287/j.1001-9332.202212.003

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We explored the effects of salt stress on the growth of Quercus mongolica and the effects of ectomycorrhizal fungi (ECMF) on the ion balance of Q. mongolica. After inoculating four kinds of ECMFs (Gomphidius visci-dus, Suillus leteus, Suillus grevillea, Boletus edulis) on Q. mongolica seedlings, we treated the annual non-mycorrhizated and mycorrhizated seedlings with NaCl stress (0, 100, 200, 300 mmol·L^-1) for 36 days, and then analyzed the mycorrhizal characteristics, growth, leaf injury symptoms, leaf electrolyte permeability, water content, and ion contents in roots, stems, and leaves. The results showed that the four ECMFs could establish a symbiotic system with Q. mongolica, and that root system of mycorrhizal seedlings was stronger than that of non-mycorrhizal seedlings. Under salt stress, the growth of Q. mongolica seedlings was inhibited, with the symptoms of scorched leaves. The damage to leaf plasma membrane and the degree of water loss were aggravated with the increases of salt stress. Under low salt stress (100 mmol·L^-1), Q. mongolica preferentially accumulated Na⁺ in roots and stems. Under medium-high salt stress (200-300 mmol·L^-1), roots became the primary organ for accumulating Na⁺. ECMF regulated ion balance in plant by increasing the Na⁺ level in roots and reducing the Na⁺ accumulation in stems and leaves, enhancing the absorption of K⁺ and Ca²⁺ to increase the K⁺/Na⁺ and Ca²⁺/Na⁺. The four ECMFs had different mitigation effects on salt poisoning of Q. mongolica. G. viscidus had the strongest effect, followed by S. leteus, while S. grevillei and B. edulis had relatively little effect.

Soil stoichiometry characteristics under different land use types in the Horqin Sandy Land, China

CAO Wen-jie, LI Yu-qiang, CHEN Yin-ping, CHEN Yun, WANG Xu-yang, GONG Xiang-wen

2022, 33(12):  3312-3320.  doi:10.13287/j.1001-9332.202212.014

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The stoichiometry characteristics of carbon (C), nitrogen (N), and phosphorus (P) is an important indicator of soil quality and ecosystem nutrient limitations. Exploring the effects of land use type and soil depth on soil nutrient stoichiometry can clarify soil nutrient cycling. In this study, we collected soil samples from sites with five different land use types (irrigated cropland, rainfed cropland, sandy grassland, fixed dunes, and mobile dunes) in the Horqin Sandy Land, and evaluated the influences of land use type and soil depth on the contents and stoichiometry characteristics of soil organic carbon (SOC), total nitrogen (TN), and total phosphorus (TP). We found that: 1) SOC (3.23 g·kg^-1), TN (0.37 g·kg^-1), and TP (0.15 g·kg^-1) contents and stoichiometry characteristics (C:N, C:P, N:P was 9.07, 25.56, 2.97, respectively) to a depth of 10 cm in the Horqin Sandy Land were significantly lower than the mean values of soils in China. 2) Soil stoichiometry characteristics differed significantly among land use types. The contents of SOC, TN, and TP to a depth of 100 cm were highest in irrigated cropland, followed by sandy grassland, rainfed cropland, fixed dunes, and mobile dunes. The C:N ratios in sandy grassland, irrigated cropland, and rainfed cropland were significantly higher than those in the fixed dune and mobile dune sites. C:P ratios in the sandy grassland, fixed dunes, irrigated cropland, and rainfed cropland were significantly higher than that in the mobile dunes. The N:P ratio differed little among the five land use types. 3) SOC and TN contents in the sandy grassland, fixed dunes, irrigated cropland, and rainfed cropland decreased with increasing soil depth. SOC, TN, and C:P in the mobile dunes and TP and C:N in all land use types showed no variation among depths. The C:P ratio of sandy grassland, fixed dunes, irrigated cropland, and rainfed cropland and the N:P ratio of sandy grassland decreased with increasing soil depth. 4) SOC, TN, and TP contents and the C:N ratio were significantly negatively correlated with the contents of medium and fine sands and with soil bulk density, but significantly positively correlated with silt+clay, and very fine sand contents. Desertification led to losses of SOC and nutrients in the Horqin Sandy Land, and exacerbated soil N deficiency. Inputs of water and ferti-lizer helped cropland to maintain a relatively high level of soil nutrients.

Spatial-temporal differentiation and driving factors of vegetation coverage in Ningxia Helan Mountain based on geodetector

LIN Yan-min, LI Wen-hui, NAN Xiong-xiong, ZHANG Jun-hua, HU Zhi-rui, NI Xi-lu, WANG Fang

2022, 33(12):  3321-3327.  doi:10.13287/j.1001-9332.202212.025

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Monitoring the regional changes in vegetation coverage and analyzing its driving factors are beneficial to realizing the sustainable development of ecological environment. Based on Landsat 5/8 remote sensing images from 1989 to 2021, vegetation coverage of Helan Mountain in Ningxia was estimated by pixel dichotomy model. In addition, the influence of 10 factors, including environmental factors and human factors, on the spatial-temporal variations of vegetation coverage was quantified by geodetector. The results showed that average vegetation coverage was 35.8% in the study area from 1989 to 2021. On the temporal scale, it showed an increasing trend, with an average increasing rate of 0.043·(10 a)^-1. On the spatial scale, vegetation coverage presented a distribution characteristic of decreasing from southwest to northeast. 58.1% of vegetation coverage in the study area would continue to improve in the future, but 30.7% of vegetation would have the potential risk of degradation. Precipitation was the dominant environmental factor driving the distribution of vegetation. Compared with single factor, the interaction between environmental factors and human factors had a stronger impact on vegetation coverage, while the interaction between precipitation and other factors played a leading role.

Effects of irrigation at flowering stage on soil nutrient and root distribution in wheat field

ZHANG Zhi-yong, QIN Bu-tan, XIONG Shu-ping, WANG Hao-zhe, XU Sai-jun, TIAN Wen-zhong, WANG Xiao-chun, MA Xin-ming

2022, 33(12):  3328-3336.  doi:10.13287/j.1001-9332.202212.018

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To provide theoretical support the full use of water and fertilizer resources for wheat, we explored the effects of irrigation on wheat yield, plant and soil nutrient distribution during flowering period and its relationship with root characteristics. We set up two treatments by using the 2 m deep soil column cultivation method with irrigation during flowering (T₁) and no irrigation during flowering (T₂), with the drought-resistant and high-yield cultivar Luomai 28 (LM28) and the high photosynthetic efficiency cultivar Bainong 207 (BN207) as materials. We measured contents of nitrogen, phosphorus and potassium in plants and soils, as well as the characteristics of soil roots. The results showed that ammonium, available phosphorus, and available potassium were mainly distributed in 0-80 cm soil layer, and that nitrate was mainly distributed in soil layer below 80 cm during wheat harvest. Irrigation at anthesis stage promoted wheat to absorb ammonium, available phosphorus and available potassium from the upper layer of soil and nitrate nitrogen from the lower layer but did not aggravate the deep leaching of nitrate. The root of wheat mainly concentrated in 0-60 cm soil layer and decreased with increasing soil depth. Dry matter accumulation, total nitrogen and total phosphorus were mainly distributed in wheat grains at maturity, while total potassium was mainly distributed in stems. Irrigation at anthesis stage significantly increased the 100-grain weight of wheat, and consequently the yield. Root morphology was negatively correlated with soil nitrate in 0-40 cm soil layer, positively correlated with soil ammonium in 80-100 cm soil layer and soil available phosphorus in 0-100 cm soil layer. Irrigation at anthesis stage promoted the full absorption of soil nutrients by roots at late filling stage, delayed the senescence of flag leaves after flowering, prolonged the functional period of transporting nutrients from vegetative organs to reproductive organs, leading nutrients in vegetative organs more fully transported to grains, increasing grain weight and yield.

Effects of straw mulching and phosphorus application on forms and availability of soil phosphorus in hilly dryland of Sichuan, China

XIANG Xiao-ling, CHEN Song-he, YANG Hong-kun, HE Peng, FAN Gao-qiong

2022, 33(12):  3337-3344.  doi:10.13287/j.1001-9332.202212.015

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We conducted a two-factor split-plot experiment to examine the alteration of soil inorganic phosphorus forms and phosphorus availability under straw mulching and phosphorus fertilizer rates. The main factor was straw mulching and non-mulching, while the sub-factor was phosphorus supply rates, including 0, 75, and 120 kg·hm^-2. We analyzed the characteristics of phosphorus adsorption-desorption, the content of inorganic phosphorus components and their relationship with available phosphorus in hilly upland purple soil in Sichuan. Results showed that compared with the non-mulching, the maximum phosphorus adsorption capacity of straw mulching was notably decreased by 7.7% and 7.4% in the two experimental years from 2018 to 2020. The degree of phosphorus saturation and readily desorbable phosphorus of straw mulching were remarkably increased by 35.4% and 21.6% in 2019 and 18.6% and 35.2% in 2020, respectively. The maximum buffer capacity of phosphorus was not different between straw mulching and non-mulching. The maximum phosphorus adsorption capacity and maximum buffer capacity of phosphorus were significantly lower, and the degree of phosphorus saturation was notably higher in the phosphorus application treatment than that under no phosphorus treatment. The readily desorbable phosphorus increased with the increases of phosphorus rates. The contents of dicalcium phosphate (Ca₂-P), octa-calcium phosphate (Ca₈-P) and iron phosphorus (Fe-P) in straw mulching treatment were notably higher than those in non-mulching treatment, whereas the content of aluminum phosphorus (Al-P) significantly lower under the straw mulching. Meanwhile, the contents of occluded phosphate (O-P) and apatite (Ca₁₀-P) tended to decrease in the straw mulching compared with that under the non-mulching. Phosphorus application increased the content of different inorganic phosphorus components. Compared with the non-mulching, soil available phosphorus content and the phosphorus activation coefficient of straw mulching remarkably increased by 23.2% and 21.3% in 2019, and 9.6% and 8.9% in 2020, respectively. Soil available phosphorus content and phosphorus activation coefficient increased with the increases of phosphorus rate. Results of regression analysis showed that the contribution of inorganic phosphorus components to the availability of available phosphorus in purple soil was Ca₂-P > Fe-P > Al-P > Ca₈-P > Ca₁₀-P > O-P. Therefore, straw mulching combined with a reasonable phosphorus fertilizer rate could promote the decomposition and transformation of insoluble soil phosphorus to moderately active or easily absorbed phosphorus forms, reduce soil phosphorus adsorption, stimulate soil phosphorus desorption, and improve soil phosphorus availability. Based on the economic benefits, phosphate fertilizer application at the rate of 75 kg·hm^-2 combined with straw mulching was recommended in Sichuan hilly dryland, which would be more beneficial in improving soil phosphorus availability.

Impacts of long-term different fertilization managements on soil acid hydrolysable organic nitrogen fractions in double-cropping rice field

SHI Li-hong, TANG Hai-ming, SUN Geng, SUN Mei, LONG Ze-dong, WEN Li, CHENG Kai-kai, LUO Zun-chang

2022, 33(12):  3345-3351.  doi:10.13287/j.1001-9332.202212.011

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To clarify the impacts of long-term different fertilization modes on the soil acid hydrolysable organic nitrogen and its components in the double-cropping rice field of southern China, a long-term (36-year) location field experiment was used as a platform to systematically analyze the variations of soil acid hydrolysable organic nitrogen and its components (amino acid nitrogen, amino sugar nitrogen, ammonium nitrogen, unidentified hydrolysable nitrogen) at 0-10 cm and 10-20 cm soil layers under four fertilization treatments, including chemical fertilizer alone (CF), rice straw and chemical fertilizer (RF), 30% organic manure and 70% chemical fertilizer (OM), and control (CK). The relationships of soil acid hydrolysable organic nitrogen content and soil total nitrogen, soil organic carbon content were also analyzed. The results showed that compared with CK, OM and RF treatments significantly increased the contents of total nitrogen, available nitrogen, and organic carbon at both soil layers. The contents of soil acid hydrolysable organic nitrogen at 0-10 cm and 10-20 cm layers of OM, RF and CF treatments were 10.7%-42.6% and 12.2% -51.5% higher than that of CK, respectively. Compared with CF and CK treatments, OM and RF treatments significantly increased the contents of amino acid nitrogen, ammonium nitrogen, unidentified hydrolysable nitrogen and amino sugar nitrogen contents atboth soil layers. The soil acid hydrolysable organic nitrogen and non-hydrolysable nitrogen contents at 0-10 cm and 10-20 cm paddy soils under different fertilization treatments decreased in an order of OM>RF>CF>CK. The contents of soil amino acid nitrogen, ammonium nitrogen, amino sugar nitrogen and non-hydrolysable nitrogen at 0-10 cm soil layer of each fertilization treatment were higher than those at 10-20 cm soil layer. In addition, the contents of soil acid hydrolyzed organic nitrogen were positively correated with the contents of soil total nitrogen and soil organic carbon. In conclusion, RF and OM treatments were beneficial to increase organic nitrogen content at 0-10 and 10-20 cm soil layers of double cropping paddy fields, with postive consequences on nitrogen supply capacity and soil fertility.

Effects of tillage with mulching on potato yield and the characteristics of soil water and temperature in arid area of southern Ningxia

HAN Gu, MIAO Fang-fang, WANG Nan, MIAN You-ming, ZHAO Fu-gui, ZHANG Long, HOU Xian-qing

2022, 33(12):  3352-3362.  doi:10.13287/j.1001-9332.202211.011

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To clarify the effects of tillage with mulching on potato yield and soil water and heat characteristics, we conducted a field experiment for two consecutive years in arid region of southern Ningxia. The results showed that tillage depths and mulching materials had significant impacts on soil water storage at 0-100 cm layer during the potato sowing period. The interactive effects of tillage depths and mulching materials were not significant. In 2019, the highest soil water storage was obtained in the subsoiling 30 cm with plastic film mulching, while soil water storage under the subsoiling 40 cm with straw mulch was the highest in 2020. Subsoiling 30 cm with plastic film mul-ching and subsoiling 40 cm with straw mulch significantly increased soil water storage by 16.9% and 33.4% compared with the plowing 15 cm with no mulch (CK), respectively. Tillage depths and mulching materials significantly affected soil water storage in the key growth period of potato. Among the tillage systems, the straw mulching plots and plastic film mulching plots had the strongest effect of soil water conservation. Irrespective of the mulching materials, soil water storage was significantly improved in the subsoiling 30-40 cm plots. Mulching materials and the interaction between tillage depths and mulching materials significantly affected soil effective accumulated temperature at 0-25 cm soil layer after sowing to budding. Among the tillage systems, the plastic film mulching plots significantly increased the average soil effective accumulated temperature by 9.3%, whereas the straw mulching plots significantly reduced the temperature by 18.7%, in comparison with no mulching plots. The highest soil effective accumulated temperature during the whole growth period was obtained in the subsoiling 30 cm with plastic film mulching and subsoiling 40 cm with plastic film mulching treatments in 2019 and 2020. The highest potato tuber yield and economic benefit in 2019 were found in the subsoiling 30 cm with straw mulching treatment, respectively, being 84.6% and 107.9% higher than CK. In 2020, the improvement effect of subsoiling 40 cm with straw mulch on potato tuber yield and economic benefit was the strongest, respectively, which were significantly increased by 81.7% and 105.7%, compared with CK. Tillage depths and mulching materials had significant interactive effects on the water and heat use efficiency of crop. The higher water use efficiency was obtained in the subsoiling 30-40 cm with straw mulch treatments, whereas the accumulated temperature use efficiency was increased significantly under different tillage depths with straw mulching treatments compared with CK. Soil water and effective accumulated temperature during the tuber formation stage were the main factors affecting potato total yield, with stronger effect of soil water than that of soil effective accumulated temperature. Therefore, the treatments of subsoiling 30-40 cm with straw mulch could improve soil moisture and heat condition, and realize potato yield and income increase and efficient use of water and heat resources, which have application and popularization value in dryland potato cultivation of southern Ningxia.

Effects of clay minerals on the transport of perfluorooctanoic acid in saturated porous media

CHEN Yi-fan, LYU Xue-yan, YU Zhi-guo, SUN Yuan-yuan, WU Ji-chun

2022, 33(12):  3363-3368.  doi:10.13287/j.1001-9332.202212.017

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We examined the effects of representative clay minerals, montmorillonite (M) and kaolin (K), on perfluorooctanoic acid (PFOA) transport under saturated conditions. Results showed that low amounts of M or K addition increased and high addition amounts reduced PFOA retardation in quartz sand during the transport. With increasing addition of clay minerals (0-50%, weight ratio), the retardation factor of the M-added system increased from 1.03±0.00 to 1.31±0.03 and then decreased to 0.72±0.06, while that of the K-added system increased to 1.30±0.02 and then decreased to 0.49±0.11. Results of the tracer experiment showed that low amount of M or K addition did not produce preferential flow, while high amount addition induced obvious preferential flow, which resulted in the decrease in PFOA retardation. In addition, due to limitations of the highly negative-charged surface of the M or K modified sand and the solid-liquid ratio of column experiment, the modified M or K sand had low adsorption capacity of PFOA and thus almost did not affect PFOA retention. However, the adsorption and desorption of PFOA by clay minerals might still be responsible for the increases in PFOA retardation with low amount of M or K addition. The results are of great significance for accurately assessing the transport process and eco-environmental risks of PFOA in soil-groundwater systems.

Identification and restoration strategy of key areas for territorial space ecological restoration in Shanghai, China based on ecological security pattern

YAN Yu-yu, SUN Yan-wei, LIU Min

2022, 33(12):  3369-3378.  doi:10.13287/j.1001-9332.202212.024

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In the new era, ecological restoration of territorial space is the important task of maintaining regional ecological security, improving regional ecological quality and providing high-quality ecological products. From the perspective of ecological security, accurately determination of key areas to be restored in the territorial space is the primary work, and it is also a key and difficult problem to scientifically carry out ecological restoration. Based on the mainstream ecological security pattern theory, taking Shanghai as the research area, we integrated morphological spatial pattern analysis method and InVEST model to identify ecological sources, extracted ecological corridors, ecological “pinch points” and obstacle points with circuit theory, comprehensively determined the key areas to be restored, and proposed targeted restoration strategies. The results showed that the ecological sources of Shanghai were mainly distributed in the Yangtze River estuary, Chongming Island, Hangzhou Bay coast, and Dianshan Lake, accounting for about 17.9% of the study area. There were 103 key ecological corridors. The key areas to be repaired included 12 ecological “pinch points” and 54 ecological obstacle points, which were mainly distributed at the border of ecological source and ecological corridor, as well asthe intersection or turning point of ecological corridor and ecological corridor. According to the typical problems of key areas to be restored and land use conditions, three types of restoration strategy zones were proposed: ecological landscape reshaping, important corridor penetration, and ecological shoreline protection and restoration. The results could provide reference for compiling a territorial space ecological restoration plan in Shanghai and building a medium-scale ecological security pattern and carrying out systemic ecological restoration work in other regions of China.

Identification of crucial areas of water supply service in Shiyang River Basin based on service flow

XU Bai-cui, PAN Jing-hu, SUN Xu-wei

2022, 33(12):  3379-3387.  doi:10.13287/j.1001-9332.202212.027

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The identification of crucial areas of ecosystem service is of great significance for accurate implementation of sustainable development measures and the improvement of regional ecosystem service. Taking Shiyang River Basin as a research unit, we analyzed the spatio-temporal variations of the provision and consumption of water supply services in 2005, 2010, 2015, and 2020. The water supply service flow model was used to quantitatively simulate water supply service flow. The ZONATION model was selected to identify the crucial areas in the Shiyang River Basin in 2020. The results showed that the provision of water supply services in the Shiyang River Basin showed a spatial pattern being high in the south and low in the north from 2005 to 2020, which declined gradually with time. The consumption showed a spatial pattern dominated by cultivated land and industrial land and temporal change with a downward trend in fluctuation. Each year, about 10.8% of water demand gap could be made up by replenishing upstream water resource. In 2020, the crucial areas of water supply service in Shiyang River Basin were 14455 km². We proposed management strategies to repair and improve the capacity of water conservation, flow promotion, and water conservation in crucial areas from the perspective of provision, transmission, and consumption.

Effects of surface and mixed application of sewage sludge on Neolamarckia cadamba root growth

DONG Xiao-quan, XING He-yan, ZHANG Shu-yuan, CHEN Jia-qian, XIE Zi-xi, DENG Wen-qi, YU Shan, WU Dao-ming

2022, 33(12):  3388-3394.  doi:10.13287/j.1001-9332.202212.010

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The utilization of sewage sludge in forests is an important way of recycling. However, the effect of sewage sludge application on woody plant root growth has been rarely reported. The effects of surface application and mixed application of sewage sludge (mass ratio in 10%) on the dynamics in root morphology of a fast-growing tree species (Neolamarckia cadamba), soil pH, electric conductivity, and heavy metal content of roots in different soil layers were analyzed by a rhizobox experiment. The relationship between root length and soil pH value, electric conducti-vity, and root heavy metal content were further analyzed. Results showed that mixed application of sewage sludge inhibited root length, root surface area, and root volume. After 120 and 240 days of mixed application, total root length in the 0-20 cm soil layer was 76.9% and 67.4% of that of no sewage sludge application, respectively. Surface application of sewage sludge did not affect root length and root surface area but increased root volume. The mixed application of sewage sludge significantly increased soil pH, electric conductivity, and root heavy metal content. Root Cd contents in 0-20 cm and 20-40 cm soil layers with the mixed application of sewage sludge were 11.5 and 10.0 times as that of no sewage sludge application, respectively. Soil electric conductivity had a significant nega-tive correlation with root length in 0-20 cm soil layer among different treatments. Root Cd content had a significant negative correlation with root length in both the surface and the mixed applications of sewage sludge. These results indicated that mixed application of sewage sludge could inhibit N. cadamba root growth mainly by increasing soil electric conductivity and root Cd content, while the surface application of sewage sludge did not affect root growth.

Degradation characteristics of 2,4,6-trichlorophenol by the anaerobic consortium XH-1

SUN Bai-hui, SONG Xue-ying, YAN Jun, YANG Yi, LYU Yan, WANG Jing-jing, SONG Yu-fang, LI Xiu-ying

2022, 33(12):  3395-3402.  doi:10.13287/j.1001-9332.202212.030

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Organic pollutant 2,4,6-trichlorophenol (2,4,6-TCP) is commonly found in anaerobic environments such as sediments and groundwater aquifers. To investigate the ability of the anaerobic consortium XH-1 to degrade 2,4,6-TCP, we established anaerobic incubations using 2,4,6-TCP as the substrate and inoculated the incubations with XH-1. Additional subcultures were established by amending with intermediate product 4-chlorophenol (4-CP) or phenol as the substrate. The transformation products of 2,4,6-TCP were analyzed and determined using high-performance liquid chromatography (HPLC). Microbial community structure and key microbial groups involved in the degradation of 2,4,6-TCP were analyzed based on 16S rRNA gene high-throughput sequencing. The results showed that the initial 122 μmol·L^-1 2,4,6-TCP was completely transformed after a 80-day incubation at a rate of 0.15 μmol·d^-1. 2,4-dichlorophenol (2,4-DCP), 4-CP and phenol were identified as the intermediate products. All intermediate products generated from 2,4,6-TCP transformation were completely degraded after being incubated for 325 days. The main microbial groups responsible for the reductive dechlorination of 2,4,6-TCP might be the organohalide respiring Dehalobacter and Dehalococcoides. The subsequent reductive dechlorination of 4-CP to phenol was likely driven by Dehalococcoides. The cooperation between the organohalide respiring bacteria, Syntrophorhabdus and methanogens (e.g. Methanosaeta and Methanofolis) was responsible for the complete degradation of 2,4,6-TCP.

Characteristics and influencing factors of microbial function in soils around a typical mining smelter

HUO Yan-hui, WANG Mei-e, JIANG Rong, CHEN Wei-ping

2022, 33(12):  3403-3409.  doi:10.13287/j.1001-9332.202212.031

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Soil microorganisms were sensitive to heavy metal pollution, whose ecological effect on soil microbial community was impacted by the interaction of contaminated stresses and environmental factors. To explore the dominant factors governing those effects in heavy metal contaminated soil, field investigation was conducted for soil from different land use types in an area surrounding a typical mining smelter in Hunan Province. Soil microbial function parameters including microbial biomass carbon (MBC), basal respiration (BR), substrate-induced respiration (SIR) and nitrification potential (PNR) were used as measure endpoints for ecological effect to reflect soil carbon and nitrogen cycling. The results showed that the effect of land use on MBC, BR, and SIR was insignificant. The dominant impacting factors on microbial functions included CaCl₂ extracted Pb (CaCl₂-Pb) and soil organic matter (SOM) content. Results of multiple regression analysis showed that soil CaCl₂-Pb and SOM together explained 39.8%-58.3% of the total variations of BR, SIR and PNR in soil, when CaCl₂-Pb and SOM ranged in 0.004-13.14 mg·kg^-1 and 0.24%-4.34%, respectively. Significantly quantitative exposure-effect equations were developed between the responses of soil BR, SIR and PNR and soil CaCl₂-Pb and SOM when soil samples with medium contents (namely, SOM 1.70%～2.36% and CaCl₂-Pb 0.004-12.98 mg·kg^-1), which meant they could be used to quantitatively assess the ecological effect of heavy metals on microbial community function as measure endpoints.

Distribution and comparison of melanin in different tissues and organs of Triplophysa stenura and T. orientalis

ZHU Zhen, TIAN Na-na, YANG Rui-bin, YANG Xue-fen

2022, 33(12):  3410-3418.  doi:10.13287/j.1001-9332.202212.040

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We examined the distribution characteristics of melanin in different tissues and organs of Triplophysa stenura and T. orientalis by using histological method. The results showed that melanin was distributed in the head skin, dorsal skin, lateral skin, peritoneal kidney layer, spinal cord cavity wall, peritoneal wall layer, pericardial cavity wall, neurocranial cavity wall and eyes of both Triplophysa species. Melanin was not found in the abdomen skin, liver chorion, gonad capsule and spleen capsule. Melanin was distributed in the dermis layer and subcutaneous layer in the skin, and in the endothelial layer or wall layer in other tissues and organs. Melanin was mainly distributed on the back, with sparse and symmetrical distribution on both sides of the body. Melanin was more abundant and densely distributed on the dorsal and lateral skin with stripes than areas without stripes. Melanin in the no stripes skin was only partially aggregated or formed intermittently distributed melanin patches. The distribution of melanin in different tissues and organs of the same Triplophysa species was different, and the percentage of distribution area and thickness of melanin layer were significantly different. However, the distribution characteristics of melanin in the same tissues and organs were similar in two Triplophysa species. The distribution of melanin in the tissues and organs of both species were related to the intensity of ultraviolet radiation they received, which was an adaptation to the intense ultraviolet radiation environment of the plateau.

Statolith microstructure and growth characteristics of Sthenoeuthis oualaniensis in the northwest Indian Ocean

WANG Hong-hao, LU Hua-jie, HE Jing-ru, LIU Kai, CHEN Xuan-yu, CHEN Xin-jun

2022, 33(12):  3419-3426.  doi:10.13287/j.1001-9332.202212.028

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Statolith is one of the most important hard tissues to study the age, growth, population structure and life history of cephalopods. In order to stuty statolith microstructure and growth characteristics of Sthenoeuthis oualaniensis in the northwest Indian Ocean, 1009 samples were collected by Chinese light falling-net fishery fleets during investigation and production in the northwest Indian Ocean from February to May of 2019. Total statolith length (TSL), lateral dome length (LDL), wing length (WL) and maximum width (MW) were taken as the indicators of morphological feature of the statolith, combined with the age data, the statolith microstructure and growth characteristics of S. oualaniensis were studied. The results showed that the statolith microstructure could be divided into postnuclear zone, dark zone and peripheral zone according to the width of growth increment. The analysis of covariance showed that there was no growth difference of TSL, LDL, WL and MW between different sexes. The relationships between TSL, WL, MW and age were best described by the power functions, while the relationship between LDL and age was best described by the linear function. In general, with the increase of age, the instantaneous relative growth rate and absolute growth rate of TSL, WL, LDL and MW decreased, and 140-180 d may be the age of sexual maturity for this squid.

Effects of water level variations on survival, morphological phenotype and responsiveness of tadpoles to phytohemagglutinin

WU Liang, GAO Ge, SHI Shuang, LI Long-xuan, PENG Xiu-juan, LI Wen-hui, WANG Ping, ZHANG Zhi-qiang

2022, 33(12):  3427-3432.  doi:10.13287/j.1001-9332.202212.037

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To investigate the responses of morphological and physiological characteristics in tadpoles of Pelophylax nigromaculatus to various water levels, a total of 480 tadpoles with similar sizes were treated with rapid, moderate and slow desiccation. Both the metamorphosis duration and average metamorphosis survival rate of specific developmental stages were counted. Their body and internal organ sizes, as well as the responsiveness to phytohemagglutinin (PHA-P) of froglets were measured after complete metamorphosis. The results showed that the metamorphosis duration of tadpoles in the control group was the longest. The average metamorphosis survival rate of different treatment groups ranged from 72.5% to 90.8%, which was the highest in the control group and the lowest in the rapid desiccation group. Body weight (BW) and body length (BL) of froglets in control and slow desiccation groups were significantly higher than those of moderate or rapid desiccation groups. Body width, ratio of BW to BL, carcass wet weight and the wet weight index of lung and fat body were the lowest in rapid desiccation group. There was no significant difference in the wet weight index of heart, spleen, kidneys and digestive organs, as well as the length index of different segments of whole digestive tract between groups. The maximal response value of froglets to PHA-P appeared at 3 h after injection in different treatments, which was significantly higher in moderate and slow desiccation groups than the control group. There was no significant difference between rapid desiccation group and any other groups. The tadpoles of P. nigromaculatus might accelerate the metamorphosis developmental process to cope with desiccation stress, accompanying with decreased atrophic body size and weakened cell-mediated immunity, which would harm tadpoles to successfully land.

Temporal-spatial distribution and ecological evaluation of macroinvertebrate functional feeding groups in Yongding River Basin

ZHANG Yu-hang, PENG Wen-qi, PENG Shuai, ZHANG Min, ZHANG Hai-ping, XIE Ying, GE Jin-jin, YU Yang, QU Xiao-dong

2022, 33(12):  3433-3440.  doi:10.13287/j.1001-9332.202212.038

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We investigated community structure of macroinvertebrate, water environment factors, hydrological factors at 23 sampling sites of the Yongding River basin from spring 2017 (April) to autumn 2017 (November). We analyzed the composition, spatial and temporal distribution of the macroinvertebrate functional feeding groups, as well as their responses to changes in riverine habitat. A total of 78 macroinvertebrate species were identified, with 52, 50 and 53 macroinvertebrate species in spring, summer and autumn respectively. The dominant functional feeding groups were gather-collectors, followed by predators, while the proportion of scrapers, filter-collectors and shredders were extremely low. Dominant species in the three seasons were all gather-collectors, including Orthocladius, Rheotanytarsus, Cricotopus in spring, Glyptotendipes in summer, and Polypedilum, Chironomus, Orthocladius in autumn. Results of redundancy analysis showed that the functional feeding groups of macroinvertebrate community structure were mainly influenced by water temperature, flow velocity, salinity, and total phosphorus in spring, by total phosphorus, dissolved oxygen, conductivity and flow capacity in summer, and by total phosphorus and dissolved oxygen in autumn. Total phosphorus had positive correlation with gather-collectors in all three seasons, indicating that the functional feeding groups of macroinvertebrates were affected by water pollution. The evaluation based on the metrics of functional feeding groups showed that: 1) in terms of material cycle, primary productivity of Guishui River were significantly higher than other regions, and that in autumn were significantly higher than other seasons. The secondary productivity and decomposition capacity of Yanghe River were significantly higher than other regions, and those in spring were significantly higher than other seasons. The autotrophy/heterotrophy of Yanghe River was significantly lower than other regions, and that in spring were significantly higher than other seasons. 2) The longitudinal transport capacity of Sanggan River was significantly higher than other regions, and that in autumn was significantly higher than other seasons. 3) The lateral input capacity of Guishui River was significantly higher than other regions, and that in summer was significantly higher than other seasons.

Reviews

Principles and implementation of the integrated management of “mountain-river-forest-farmland-lake-grassland-sandland” in Horqin Sand Land, China

LIU Zhi-min, YU Hai-bin, WANG Hai-yang

2022, 33(12):  3441-3447.  doi:10.13287/j.1001-9332.202212.026

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Integrated management of “mountain-river-forest-farmland-lake-grassland-sandland” has become an important concept of ecological environment construction in arid areas. Although some major projects have been implemented in the sand areas, but the scientific and technical principles of integrated management are not clear and have not been fully reflected in these projects. Considering such cases, we discussed the challenges, scientific principles, technical principles and implementation priorities of the integrated management of Horqin Sand Land. In Horqin Sand Land, the relationships between forest and farmland, forest and forest, forest and water, farmland and water, forest and grassland, sand land and water, farmland and grassland were not well coordinated, resulting in resource imbalance and low ecologic services. The integrated management should follow scientific principles and laws, including aeolian sand movement law, grassland interface theory, water resource balance theory, biodiversity maintenance theory, landscape ecology theory, and ecosystem services. At the technical level, the principles of water-sediment relationship coordination, landscape design optimization, prevention and control technologies and modes multi-directional synergia, natural and man-made landscapes harmonies, “production-ecological” space layout balance should be highlighted. The key points of integrated management should focus on the function improvement of sand dunes and shelter forests, the efficiency improvement of farmlands and grasslands, the ecological conservation of lakes, the greening and beautification of human settlements, the ecological restoration of engineering projects. This review could provide reference for the integrated ecological environment construction in Horqin Sand Land and the sand areas of northern China.

Review on the speciation analysis methods of platinum group metals in environmental media

LIU Zhan-ming, ZENG Yue, LI Yun-qing, MU Jing-li, WU Ming-xiu, CAO Wen-zhen

2022, 33(12):  3448-3456.  doi:10.13287/j.1001-9332.202212.032

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Platinum group metals (PGMs) present a variety of forms in the environment, and analysis of speciation is essential for identifying their ecological risk. Here, we reviewed the methods for the morphological analysis of three major PGMs (platinum, palladium and rhodium) in the environment, including chemical sequential extraction, hyphenated techniques for instruments, computer simulations. We outlined the types, characteristics and applications of these methods, elaborated the weaknesses, and provided prospects for future development. Among them, chemical sequential extraction is universally applied in the morphological analysis of solid-phase samples, with diverse extraction conditions and procedures proposed in the current study. However, it has not been well standardized. The hyphenated techniques for instruments have significant advantages for the determination of elemental forms in solution, of which capillary electrophoresis system can separate similar substances with the same electrophoresis ability. Liquid chromatography systems have better performance in terms of separation capacity and detection limit. The computer simulations further expand the access to morphological analysis, enabling complex morphological calculations. It was proposed to combine multiple methods in the future to continuously improve the accuracy of analytical techniques by complementing and optimizing each other.