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Table of Content

    20 January 2019, Volume 30 Issue 1
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    Special Topic of Fluorine Pollution
    Fluorine emission list of China’s key industries and soil fluorine concentration estimation.
    GUO Shu-hai, GAO Peng, WU Bo, ZHANG Ling-yan
    2019, 30(1):  1-9.  doi:10.13287/j.1001-9332.201901.002
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    Industry-induced fluorine emissions and high background values of fluorine in soil lead to serious fluorine pollution in some regions of China, posing a serious threat to ecological security and human health. Based on the production capacity of China’s key industries contributing to fluorine emission, we estimated the fluorine emissions of key industries and built a fluorine emission list in China. Based on data integration and fusion, the soil fluorine background value, fluorine geochemical distribution and soil fluorine concentration distribution in China were analyzed. Then, the causes and control of fluorine pollution in typical areas were analyzed. The results showed that productions of steel, phosphorus fertilizers and electrolytic aluminum were the key industries for fluorine emissions in China. The highest fluorine emission was from the application of phosphorus fertilizers. Due to the huge area of P application, its contribution to soil fluorine concentration was negligible. Electrolytic aluminum production resulted in a high intensity of fluorine emission. A high amount of fluorine was discharged with steel industry production, with low emission intensity. In most parts of China, the soil fluorine background value is low and the environmental capacity is large. In some areas of China, however, fluorine pollution is serious, mainly due to industrial fluorine emissions and high background values of fluorine in soil. These regions should take corresponding prevention and control measures.
    Fluorine speciation in soil and the remediation of fluorine contaminated soil
    YUAN Li-zhu, WANG Jia-ning, MA Chun-yang, GUO Shu-hai
    2019, 30(1):  10-20.  doi:10.13287/j.1001-9332.201901.003
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    In China, fluoride pollution in soil is severe and poses a serious threat to human health and ecological security. However, how to control fluorine-contaminated soil has not received widespread attention. Here, we summarized fluorine speciation in soil and its main chemical reactions in water-soil system and reviewed the research progress on the remediation of fluorine-contaminated soils. Then, we proposed the focus of future research on fluorine-contaminated soil remediation. The aim of this review was providing the reference for the remediation of fluoride-contaminated soil. There are five forms of fluorine in soils, with the proportion of residual fluorine being over 90%. The reactions of fluorine in the soil solution mainly include precipitation-dissolution, complexation-dissociation, and adsorption-desorption. At present, the remediation technology of fluorine contaminated soil mainly focused on chemo-immobilization, chemical leaching, electrokinetic remediation, and phytoremediation. Clarifying the combined forms of fluorine in soil, screening functional microorga-nisms and plants, developing the combined remediation technology will be the focus of future research. Ultimately, on site fluorine-contaminated soil remediation could be implemented.
    Environmental and geochemical behaviors of fluorine and its impacts on ecological environment
    TU Cheng-long, HE Ling-ling, CUI Li-feng, ZHANG Qin-hai, ZENG Qi-bing, PAN Xue-li, GUO Shu-hai
    2019, 30(1):  21-29.  doi:10.13287/j.1001-9332.201901.004
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    In past decades, fluorine exposure of plants and human caused by regional geochemical anomalies of fluorine or environmental pollution has received widespread concerns. Many in-depth researches have been conducted on the geochemical behavior of fluorine in different environmental media, but with disputes and uncertainties. We reviewed the research advances on geochemical behaviors of fluorine in the atmosphere, water and soil, including source, quantity, existence form, migration, transformation, and controlling factors. The observation of correlation between geochemical behaviors of fluorine and plant and human fluoride exposure was also reviewed. Moreover, we proposed that the future research on environmental geochemical behaviors of fluorine should give priority to particular directions.
    Principle and techniques for fluoride pollution control in drinking water
    LIU Rui-ping
    2019, 30(1):  30-36.  doi:10.13287/j.1001-9332.201901.005
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    Long-term natural geochemical processes result in wide occurrence of fluoride contamination in underground water and fluoride exposure via drinking water for over 500 million people glo-bally. The control of fluoride pollution and fluorosis is one of the most important issues for drinking water safety. In the past several decades, many initiatives failed in defluoridation of water. Better understanding of fluoride occurrence mechanisms in underground water chemistry and the prediction of high-risk areas by geographic information and remote sensing are of crucial importance to minimize fluorosis occurrence. The use of alternative source water or blending should be considered as priority option. Much efforts should be devoted to the fundamental studies on defluoridation reagents and innovative materials, and to the development of highly-efficient, economic, easy-to-handle and stable technologies and integrated instruments. Furthermore, the design, construction, operation, and supervision of defluoridation facilities should be carefully evaluated and strengthened to achieve stable benefits as much as possible.
    Biological exposure limits caused by co exposure to fluoride and arsenic based on Wnt signaling pathway
    ZENG Qi-bing, XU Yu-yan, TU Cheng-long, YU Xian, YANG Jun, HONG Feng
    2019, 30(1):  37-42.  doi:10.13287/j.1001-9332.201901.023
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    Chronic fluoride-arsenic combined poisoning is a global public health problem. While the cause of the disease is clear, the pathogenesis is unknown. Given that there is no specific treatment, early prevention is particularly important. Biological exposure limits are designed to investigate the maximum allowable concentration of harmful effects from exogenous chemicals. To explore the biological exposure limits for mixed exposures of fluoride and arsenic, we compared the contents of fluorine and arsenic in the environmental media of the control and fluoride-arsenic combined exposure areas and analyzed the dose-effect and dose-response relationship between fluoride, arsenic and the key proteins of Wnt signaling pathways. The benchmark dose method was used to estimate the biological exposure limit for fluoride-arsenic combined exposure. The results showed that the content of fluoride in coal, clay, indoor air, outdoor air, chili and rice, as well as arsenic content in coal, clay, outdoor air, chili and rice was higher than that of the control. With the increase of fluoride and arsenic exposure levels, the glycogen synthase kinase 3β (GSK3β), β-catenincontents and the prevalence of Wnt/β-catenin signaling pathway antagonistic protein Dickkopf-1 (DKK1), GSK3β, Beta-catenin (β-catenin) gradually increased, but the content of DKK1 significantly decreased. Based on the Wnt signaling pathway, the biological exposure limit for fluoride-arsenic combined exposure was urinary fluoride of 0.52 mg·g-1 creatinine and urinary arsenic of 6.59 mg·g-1 creatinine. Our results had important guiding significance for early prevention of body damage caused by fluoride-arsenic combined poisoning.
    Relationship between fluoride exposure, orthopedic injuries and bone formation markers in patients with coal-burning fluorosis
    WANG Xi-lan, MING Juan, QIU Bing, LIAO Yong-fang, LIAO Yu-dan, WEI Shao-feng, TU Cheng-long, PAN Xue-li
    2019, 30(1):  43-48.  doi:10.13287/j.1001-9332.201901.026
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    Chronic exposure to fluoride is a public health problem worldwide. We explored the relationship between fluoride exposure, orthopedic injuries and bone formation markers alkaline phosphatase (ALP), bone Gla protein (BGP) in participants with coal-burning fluorosis in Hehua Village (coal-burning fluorosis endemic area) in Zhijin County of Guizhou Province and Zhangguan Village (non-fluoride contaminated area) in Anshun City of Guizhou Province. Environmental samples were collected and fluoride contents were examined using a fluoride ion-selective electrode. Dental fluorosis and skeletal fluorosis of 295 participants from Hehua Village and 85 participants from Zhangguan Village were diagnosed with informed consent. Urinary samples and peripheral blood samples were collected from the participants to determine urinary fluoride (UF), ALP acti-vity, and BGP content. The results showed that fluoride contents in rice, pepper, corn, drinking water, clay, vegetable-grown soil, coal and indoor and outdoor air were significantly higher than those in the control area, but lower than the previously reported values. With the increases of UF concentration, the ALP activity and BGP content significantly increased, the severity of skeletal fluorosis was greater, but with no significant changes in dental fluorosis. There was positive correlation between the severity of skeletal fluorosis and ALP activity, BGP content. These results indicated that low fluoride exposure could cause orthopedic injuries. ALP and BGP could be used to eva-luate the bone turnover in patients with skeletal fluorosis, which would be useful in the auxiliary diagnosis and therapeutic evaluation of skeletal fluorosis.
    Original Articles
    Community characteristics and canopy structure of pine-oak forest at the Lingkong Mountain in Shanxi, China
    DUAN Jia-rui, ZHANG Quan-xi, BAI Jia-ye, GUO Dong-gang
    2019, 30(1):  49-57.  doi:10.13287/j.1001-9332.201901.027
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    We conducted a field investigation at 400 10 m×10 m quadrats in a 4-hm2 plot of mixed forest dominated by pine (Pinus tabuliformis) and oak (Quercus wutaishanica), which was established in 2011 in the Lingkong Mountain of Shanxi Province, China. The community characteristics in the year of 2016 were analyzed. The digital hemisphere photograph (DHP) approach was employed to measure the canopy structure and the understory light parameters. The results showed that a total of 5558 individuals of trees of 25 species from 15 genera and 10 families were recorded. The canopy openness (CO) varied from 15.0% to 25.0%, the leaf area index (LAI) varied from 1.5 to 2.5, and the understory light parameters varied from 10.0% to 30.0%. The distribution of dominant species drove the canopy structure and the undergrowth light factors. The canopy structure defined the impacts of light factors in the forest. The leaf area index was more optimal in describing the canopy’s dynamic function. The canopy openness and leaf area index were negatively correlated to understory light availability, especially to the abundance of the incident rays of diffused light. Since the canopy structure was relatively uniform in the temperate pine-oak mixed forest, the understory light spots generally distributed in clusters. The tree species and canopy structure had significant effects on light environment in the forest.
    Effects of different disturbance patterns on stand structure of infected pure Pinus massoniana plantation
    WU Min-juan, YOU Yu-jie, ZHANG Xiao-hong, WANG Yi-xiang, QIU Wan-ting, LYU Yu-long, YING Bin-bin, CHEN Shi-yue
    2019, 30(1):  58-66.  doi:10.13287/j.1001-9332.201901.007
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    To explore the effects of different disturbance patterns on restoring the health of an infected stand, concentrated disturbance of not cutting trees before 10 years after infection, mode-rate disturbance of cutting infected pine trees, and strong distrubance of cutting infected pine trees, the neighboring trees and poorly growing pine trees were compared in a pure Pinus massomiana plantation infected by Bursaphelenchus xylophlius in Anji, Zhejiang, China. After 16 years, the importance values of P. massoniana in the three treatments were: concentrated disturbance > mode-rate disturbance > strong disturbance. However, the importance values of broad-leaved trees showed the opposite trend. Compared with the concentrated disturbance, the average DBH of P. massoniana in the moderate and strong disturbance treatments were 1.2 and 1.7 times higher, respectively, and those of broad-leaved species were 1.3 and 1.9 times higher, respectively. The average height of pine trees in the moderate and strong disturbance treatments increased 1.5 and 2.0 times, respectively, and those of broad-leaved species 1.2 and 1.8 times, respectively. The tree volume per hectare in moderate and strong disturbance treatments were 5.2 and 3.8 times that of concentrated disturbance treatment, respectively. In the moderate and strong disturbance treatments, the number of trees in each diameter class was greater than in the concentrated disturbance treatment. The stand diameter distribution in the multi-storied moderate and strong disturbance treatments followed an inverse J-shaped curve. The species richness and biodiversity were significantly higher in the mode-rate and strong disturbance treatments than in the concentrated disturbance treatment. The individual size inequality and structural complexity indices followed the order of moderate disturbance > strong disturbance > concentrated disturbance. Under moderate and strong disturbance treatments, the single-storied and evenly aged pure P. massoniana plantation became multi-storied and unevenly aged mixed stands. All the three disturbance patterns promoted the succession of broad-leaved trees, with the pace of succession in the order of strong disturbance > moderate disturbance > concentrated disturbance. In conclusion, moderate disturbance achieved better restoration. Thinning pure P. massoniana plantation could accelerate the succession of a mixed stand to enhance resistance against Bursaphelenchus xylophlius invasion.
    Interspecific associations of the main tree populations of the Cyclobalanopsis glauca community in Karst hills of Guilin, Southwest China
    TU Hong-run, LI Jiao-feng, YANG Li-ting, BAI Jin-lian, LU Guo-qiong, LI Heng-chun, LIANG Shi-chu, JIANG Yong
    2019, 30(1):  67-76.  doi:10.13287/j.1001-9332.201901.018
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    Analyzing the interspecific association of major tree populations of Cyclobalanopsis glauca community and revealing the coexistence among the populations would provide theoretical basis for the restoration and reconstruction, management and biodiversity conservation of Karst hills in Gui-lin. Based on field survey, the χ2 test, association coefficient (AC), co-occurrence percentage (PC), Ochiai index (OI), Dice index (DI), and principal component analysis (PCA) were used to investigate the interspecific association and eco-taxonomic classification of the top 22 tree species in Cyclobalanopsis glauca community in Guilin Karst Rocky Mountains. The results showed that there was a significant positive correlation between the interspecific associations of the 22 main tree populations, indicating that this community was in a stable climax stage. The results of χ2 test showed that 108 pairs of 231 species pairs had positive associations, 115 species pairs had negative associations, 8 species pairs were unrelated, with the positive and negative linkage ratio being 93.9%. The vast majority of species pairs showed no significant association. The strong indepen-dence between species might be mainly caused by the higher habitat heterogeneity of the Karst hills in Guilin which led to the differentiation of niches between species. The results of AC, PC, OI and DI were basically consistent with that of χ2 test, indicating that the analysis of interspecific association should be based on the χ2 test and supplemented by AC, PC, OI and DI indices. According to the PCA and evaluation of interspecific relationships, the 22 main tree species were divided into three ecological groups. The species within each group had the same adaptability to habitat but different ecological requirements.
    Influence of snow depth changes on leaf litter decomposition of Fraxinus mandshurica and Larix gmelinii
    DOU Jia,WANG Chuan kuan,WU Qi qian
    2019, 30(1):  77-84.  doi:10.13287/j.1001-9332.201901.038
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    Changes in snowpack induced by climate change can profoundly affect forest litter decomposition. A snow depth manipulation experiment with three treatments (i.e.,control,snow addition, and snow removal) was conducted to assess the effects of snow depth changes on leaf litter decomposition of two temperate tree species [Manchurian ash (Fraxinus mandshurica) and Dahurian larch (Larix gmelinii)]. The annual loss of the litter mass after one year decomposition varied between 51.3% and 57.4% for the ash and between 21.7% and 31.4% for the larch. The decomposition constants (k) ranged from 0.048 to 0.057 and from 0.022 to 0.030 for these two species respectively.The greatest k value occurred under the snow addition treatment, while the least occurred under the snow removal treatment.Snow addition treatment shortened the 50% and 95% decomposition time by 1.1 months and 4.2 months for the ash, respectively, and by 3.7 months and 15.5 months for the larch, respectively. The snow removal treatment lengthened those decomposition time by 1.8 months and 6.4 months for the ash,and by 5.0 months and 21.1 months for the larch, respectively. Litter decomposition rate was significantly correlated with tree species, snow depth, decomposition time, and soil temperature, but its major influencing factors varied with decomposition stage. Soil temperature and the initial litter quality were the major factors affecting decomposition rates during the snow covered and following snow free periods, respectively. Our findings highlight that changes in snow depth exert significantly instantaneous and prolonged effects on forest litter decomposition.
    Effects of Cinnamomum camphora leaf litter cover on soil carbon and nitrogen cycles under different water conditions
    LIU Shu-lu, ZHANG Hao, TIAN Wen-feng, GUI Guang-zhao, WU Ting, YU Jian, ZHAO Juan
    2019, 30(1):  85-94.  doi:10.13287/j.1001-9332.201901.034
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    Litter, as an important carbon stock, plays a significant role in carbon and nitrogen cycle in forest soil. To examine the effects of Cinnamomum camphora leaf litter on soil carbon and nitrogen cycles, the contents of carbon and nitrogen were investigated in C. camphora leaf litter-covered forest soils with the water content of 10%, 20% and 30% under laboratory-controlled condition. The results showed that leaf litter cover significantly increased both soil CO2 emission rates and water soluble organic carbon (WSOC) content, but decreased soil nitrate nitrogen content under the three water conditions, indicating that leaf litter cover could improve soil respiration and carbon mineralization but inhibit soil nitration. Leaf litter cover significantly enhanced the content of soil ammonium with the water content of 10%, but reduced those in soils with water content of 20% and 30%, revealing that the effects of leaf litter cover on soil ammonium nitrogen contents was dependent on soil water content. The content of some monoterpenes in leaf litter had a significantly positive correlation with soil CO2 emission rate and ammonium content, but a prominently negative relation with soil WSOC and nitrate content, implying that the effects of leaf litter cover on soil carbon and nitrogen cycles might be attributed to monoterpenes in leaf litter.
    Soil bacterial community structure and predicted functions in the larch forest during succession at the Greater Khingan Mountains of Northeast China
    LI Ping, SHI Rong-jiu, ZHAO Feng, YU Jing-hua, CUI Xiao-yang, HU Jin-gui, ZHANG Ying
    2019, 30(1):  95-107.  doi:10.13287/j.1001-9332.201901.010
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    To reveal soil bacterial community structure and potential functions in larch forest during succession at Greater Khingan Mountains (Hanma National Nature Reserve), 16S rDNA was sequencing by Illumina Miseq. The results showed that the Proteobacteria, Acidobacteria, Verrucomicrobia, Bacteroidetes, Actinobacteria, Planctomycetes and Chloroflexi were the most dominant phyla in soils of larch forests at various successional stages. Along forest succession, Acidobacteria increased, while Chloroflexi decreased. Relative abundance of dominant phyla was different at various successional stages. The α diversity, Chao1, Shannon index and Simpson index of soil bacterial community had no significant difference among five succession stages, while significant differences in soil bacterial community structure were observed between young and medium larch, between young and over mature larch, and between near mature and mature larch. Bacterial community structure was mainly influenced by redox potential, pH and available phosphorus. The redox potential was the most important factor influencing soil bacterial community structure. Along the succession of larch forest, N-fixation, denitrification, ammonia oxidation and lignin breakdown decreased, dissimilatory sulfate reduction had down-up trend, carbon fixation had up-down trend, and alkaline phosphatase had no apparent trend. Bacterial community potential function was mainly influenced by redox potential and available phosphorus.
    Soil bacterial community characteristics under different microhabitat types on Maolan karst forest, Guizhou, Southwest China
    WU Qiu-sheng, LONG Jian, LIAO Hong-kai, LIU Ling-fei, LI Juan, WU Jin-nan, XIAO Xiong
    2019, 30(1):  108-116.  doi:10.13287/j.1001-9332.201901.014
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    We analyzed the diversity, community composition and relative abundance of soil bacteria communities in five different types of microhabitats (included stone caverns, stone crevices, stone gullies, stone grooves, top-soils) in Maolan karst forest, Guizhou Province, China. Bacterial 16S rRNA V3-V4 variable regions were analyzed by high-throughput sequencing technique. We examined the effects of soil physicochemical factors on bacterial community structure. The results showed that 27 phyla, 64 classes, 128 orders, 242 families, 367 genera, and 704 species were detected in the soils from five types of microhabitats. Proteobacteria, Actinomycetes, Acidobacteria, Chlorofleixi and Nitrospirae were the dominant bacterial phyla. Actinomycetes was the dominant phyla in the microhabitats of top-stone cavern (0-10 cm), sub-stone cavern (10-20 cm), stone crevice, and stone groove. Acidobacteria was the dominant phyla in the top-soil (0-10 cm) and the sub-soil (10-20 cm). Proteobacteria was the dominant phyla in the top-stone gully (0-10 cm) and the sub-stone gully (10-20 cm). The highest soil bacterial Simpson index was found in stone crevice microhabitat, while the lowest was found in sub-soil (10-20 cm) microhabitat. Results from the LEfSe analysis showed that the number of distinct indicator species at the different levels of taxo-nomy was higher in the top-soil (0-10 cm), sub-soil (10-20 cm), sub-stone cavern (10-20 cm), and the stone groove than in the stone crevice, the top-stone gully (0-10 cm) and sub-stone gully (10-20 cm). The indicator phyla were Actinobacteria and Chlorofleixi in the sub-stone cavern (10-20 cm). The top-stone gully (0-10 cm) were characterized by the phyla of Proteobacteria and Tectomicrobia. The top-soil (0-10 cm) was featured by Acidobacteria, Verrucomicrobia and Latescibacteria. The sub-soil (10-20 cm) was dominated by Nitrospirae. There were no indicator species in stone groove, stone crevice, and sub-stone gully (10-20 cm). There was no indicator species in phylum to genus in top-stone cavern (0-10 cm). RDA and ABT analysis showed that soil organic matter, pH, and available phosphorus explained a large part of the variation regarding the responses of bacterial community to the changes in basic physicochemical factors in the soil.
    Effects of nitrogen addition on the structure of rhizosphere microbial community in Pinus tabuliformis plantations on Loess Plateau, China
    LIU Gui-yao, CHEN Li-li, YUAN Zhi-you
    2019, 30(1):  117-126.  doi:10.13287/j.1001-9332.201901.025
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    Atmospheric nitrogen deposition in China displays a pronounced southeast-northwest gradient, with a range of ～35 kg·hm-2·a-1 in southern and central China and ～7.55 kg·hm-2·a-1 in the northwest. With the “Grain for Green” project, the environment of Loess Plateau has been greatly improved in the past decades. Little is known about how nitrogen deposition impacts the soil microbial communities in plantations in this region. In order to investigate the responses of diversity and structure of soil microbial community in Pinus tabuliformis plantations to nitrogen addition on Loess Plateau, China, we used high-throughput sequencing of 16S ribosomal RNA genes of bacteria and ITS genes of fungi to investigate the effects of nitrogen addition (200 kg N·hm-2·a-1) on the bacterial and fungal community over a 40-year chronosequence of coniferous P. tabuliformis plantation forests. After nitrogen addition, the Shannon diversity of both bacteria and fungi significantly increased in the 25-year-old stand, while the abundance-based coverage estimator of bacteria increased significantly in the 40-year-old stand. Nitrogen addition enhanced the relative abundance of Bacteroidetes in the 40-year-old stand and that of Acidobacteria/Zygomycota in the 25-year-old stand. In contrast, the relative abundance of Thaumarchaeota was reduced by nitrogen addition in the 40-year old stand. The effects of nitrogen addition were stronger on bacterial than on fungal community structure as indicated by the results from non-metric multidimensional scaling analysis. Moreover, the effects of nitrogen addition were stronger in the 25-year-old stand than in the 40-year-old stand. These results indicated that the effects of nitrogen addition on microbial community structure diminished over time in temperate forests on Loess Plateau, China. The stronger effects of nitrogen addition was found on the community structure of bacteria than that of fungi, and on the microbial community structure in the 25-year-old stand than in the 40-year-old stand. Our findings suggested that forest ecosystem at a certain stage (～40-year old) would be less sensitive to disturbance such as nitrogen addition than young forests.
    Effects of enclosing on soil microbial community diversity and soil stoichiometric characteristics in a degraded alpine meadow
    YIN Ya-li, WANG Yu-qin, LI Shi-xiong, LIU Yan, ZHAO Wen, MA Yu-shou, BAO Gen-sheng
    2019, 30(1):  127-136.  doi:10.13287/j.1001-9332.201901.009
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    Enclosing is an effective rehabilitation measure for degraded pastures that mimics natural recovery of vegetation. To examine the interaction between biotic and abiotic in lightly degraded and enclosing grasslands is helpful for a clear understanding of the structure and function of grassland ecosystem. In this study, soil microbial community and soil stoichiometric characteristics in lightly degraded and 10-year enclosing alpine meadows were studied by high-throughput sequencing and Biolog-Eco methods. The results showed that compared with lightly degraded grassland, the concentration of soil NH4+-N in the enclosing grassland increased significantly, while total K (TK) dramatically decreased. There was no obvious variation in soil total organic carbon (TOC), total N (TN), total P (TP), NO3--N, available P (AP), available K (AK), microbial biomass C (MBC) and microbial biomass N (MBN). The soil microbial biomass C/N was significantly enhanced. The carbon metabolic capabilities of soil microbes in different soil layers of alpine mea-dow were obviously increased with the prolonged incubation time, but there was no significant difference between lightly degraded and enclosed meadows. The OTUs of soil bacteria was significantly higher than that of fungi in alpine meadow. The microbial similarity between lightly degraded and fencing grasslands was 27.0%-32.7%. Enclosing significantly increased the fungal relative richness of Ascomycota, Zygomycetes and Chytridiomycota, while simultaneously decreased the rela-tive abundance of Basidiomycetes. Compared with lightly degraded meadow, the bacterial relative richness of Acidobacteria significantly decreased in enclosing meadow. The community composition of soil fungi and bacteria greatly varied among different soil layers. There was significant difference of fungal community composition in the upper soils between lightly degraded and enclosed grassland. The soil bacterial community diversity was greatly affected by soil TN and AK, while the fungal community diversity was significantly affected by plant aboveground biomass. Soil AK produced great influence on soil microbial carbon source utilization capacity. Generally, long-term grazing exclosure had no significant effects on soil nutrients and soil microbial community diversity of lightly degraded grassland and thus would waste the pasture resources, whereas appropriate grazing could maintain the sustainable utilization of grassland.
    Effects of vegetation restoration on nutrient and microbial properties of soil aggregates with different particle sizes in the loess hilly regions of Ningxia, Northwest China
    LI Qiu-jia, XUE Zhi-jing, ZHOU Zheng-chao
    2019, 30(1):  137-145.  doi:10.13287/j.1001-9332.201901.022
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    We explored the effects of vegetation restoration on the soil nutrients and microbial pro-perties of soil aggregates with different particle size by comparing soils in a natural grassland which had been restored for nearly 30 years and in cropland in the loess hilly regions of Ningxia. We analyzed the soil organic carbon (SOC), total nitrogen (TN), microbial biomass carbon (MBC), microbial biomass nitrogen (MBN), soil basal respiration (CO2-C) and respiratory quotient (qCO2) of different particle size soil aggregates collected from cropland and natural grassland. The results showed that soil aggregates of natural grassland had more micro-aggregates (particle size <0.25 mm), higher nutrient concentrations (SOC, TN and available K) and C/N than that of cropland. The highest concentrations of SOC and TN in 1-2 mm aggregates and higher C/N in natural grassland and cropland suggested that vegetation restoration could improve the capacity of soil aggregates to reduce nutrient loss and accumulate organic matter, with the highest nutrient accumulation in 1-2 mm aggregates. Microbial biomass (MBC, MBN) and CO2-C in natural grassland were higher than in cropland, but the qCO2 was significantly lower, suggesting that vegetation restoration could effectively improve soil microbial biomass and activity, and make soil habitats more stable. The magnitude of responses of the microbial characteristics of different particle aggregates to vegetation restoration varied due to the differences in nutrient characteristics. The MBC of 1-2 mm aggregates, the MBN of <0.25 mm, 0.25-1 mm and 1-2 mm aggregates, the microbial activity of 1-2 mm and >5 mm aggregates were more sensitive than the rest of the particle aggregates of vegetation restoration. In conclusion, vegetation restoration could effectively improve the fertility and structural characteristics of soil aggregates, and the most prominent improvement was in 1-2 mm particle size aggregates.
    Hillslope-scale stochastic simulation of soil moisture dynamics in fixed dunes at the southern edge of Gurbantunggut Desert, China.
    YIN Xin-wei, ZHENG Xin-jun, LI Yan, HU Shun-jun, GUO Yong
    2019, 30(1):  146-156.  doi:10.13287/j.1001-9332.201901.015
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    To examine the effects of soil moisture dynamics on hydrological and ecological processes at the hillslope scale in the desert region, a hillslope-scale soil moisture dynamic stochastic model in arid sandy based on Rodriguez-Iturbe soil moisture dynamic stochastic model (RI model) was developed by modifying the input parameters of the model. Using the continuously monitored data of soil moisture in root zone during growing season from 2015 to 2016 and daily precipitation from 2000 to 2016 in a fixed dune at the southern edge of Gurbantunggut Desert, we analyzed soil moisture dynamics and probability density function of soil moisture on slopes in growing season and discussed the sensitivity of parameters of the stochastic model and its application feasibility. The results showed that the seasonal distribution of precipitation was irregular. The total number of annual precipitation was mainly derived from the precipitation of >10 mm. The precipitation frequency and interval were dominated by <5 mm and <10 d, respectively. The precipitation in the eastern slope was slightly larger than that in the western slope. The interannual variability of soil moisture in the eastern and western slopes in the growing season was basically consistent with the rainfall distribution. The soil moisture in the root zone in the western slope was slightly lower than that in the eas-tern slope, and the soil water content in different slope positions followed a normal distribution. The curve characteristics of the soil moisture probability density function (the curve peak value, the position of the peak, the confidence interval of 95%) in the root zone in the different slopes in growing season simulated by the hillslope-scale model were consistent with observed values, with the consistency measure (CM) being higher than 0.5. Such a result indicated that the hillslope-scale stochastic model could be used for simulating the soil moisture probability density function in diffe-rent slope positions in the study area, with a good applicability. This model could provide theoretical basis and scientific methods for vegetation survival or restoration and the implementation of ecological construction project of desertification control in arid sandy area.
    Root habitat flexibility of seabuckthorn in the Pisha sandstone area
    WANG Hao, HUANG Chen-lu, YANG Fang-she, LI Huai-en
    2019, 30(1):  157-164.  doi:10.13287/j.1001-9332.201901.024
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    We examined root fractal parameters, root length, root quantity, root mass, root-shoot ratio of 3-year-old seabuckthorn in the Pisha sandstone area of Inner Mongolia, using the fractal theory and statistical method. The results showed that soil moisture had the most significant effect on the root architecture, followed by slope. Slope position had the least effect on the root architecture. The seabuckthorn in the Pisha sandstone area was suitable for planting on slope bottom or mid-slope with a soil moisture of about 8%. Mid-slope with a slope of 30°-35° was recommended. The root-shoot ratio of seabuckthorn decreased with increasing soil moisture. It increased at first and then decreased with increasing slope and slope position. Seabuckthorn with the characters of developed root and high root-shoot ratio in arid and barren midslope meets the basic requirements of tree species for soil-fixing and slope-protection.
    Allometry between twig size and leaf size of typical bamboo species along an altitudinal gradient
    SUN Jun, WANG Man-tang, CHENG Lin, LYU Min, SUN Meng-ke, CHEN Xiao-ping, ZHONG Quan-lin, CHENG Dong-liang
    2019, 30(1):  165-172.  doi:10.13287/j.1001-9332.201901.029
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    To investigate the trade-off between the twig size and leaf size, we measured the total leaf mass, stem mass, individual leaf mass and leafing intensity of typical bamboo’s (Phyllostachys edulis, Indocalamus tessellatus, Oligostachyum oedogonatume, Yushania hirticaulis and Yushania wuyishanensis) twigs at different altitudes in Wuyi Mountain. The results showed that the exponents of the scaling between total leaf mass and stem mass on twigs significantly decreased with increasing altitude for all the five bamboo species. The common scaling exponents of total leaf mass vs. stem mass for P. edulis, I. tessellatus and O. oedogonatum were 0.94, 0.85 and 0.84, respectively. A common slope of 0.79 was observed in total leaf mass vs. stem mass in Y. hirticaulis and Y. wuyishanensis. There was significant negative correlation between individual leaf mass and leafing intensity among bamboo species, except Y. wuyishanensis. A common slope of -1.12 existed between individual leaf mass and leafing intensity for five bamboo species. In conclusion, bamboos at low altitudes tended to support more leaf biomass while preferring to invest more to stem biomass at high altitudes. Although the stem mass investment of different bamboo’s twig increased with altitude, the leafing intensity strategies based on stem mass were determined by the leaf size construction rather than altitude.
    Phosphate solubilizing characteristics of Talaromyces aurantiacus and its growthpromoting effect on Phyllostachys edulis seedlings
    WU An-qi, ZHANG Yang, WAN Song-ze, FANG Xiang-min, LIU Ren, HU Tian-yi, CHEN Fu-sheng
    2019, 30(1):  173-179.  doi:10.13287/j.1001-9332.201901.011
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    To investigate phosphate-solubilizing characteristics and plant growth-promoting effect of Talaromyces aurantiacus (JXBR04) from Phyllostachys edulis rhizosphere soil, the influence of culture time, carbon sources, nitrogen sources, initial pH, liquid filling volume, and salt ions on phosphate solubilizing ability of strain JXBR04 were examined. The capability to solubilize different types of mineral phosphate was detected using a liquid fermentation method. A pot experiment was conducted to evaluate the effects of strain JXBR04 in promoting the growth of Ph. edulis seedlings. The results showed that strain JXBR04 displayed the highest phosphate-dissolving capacity when the cultivation period was 7 days, the initial pH reached 3.5, the volume of liquid was 1/5 or 2/5, and the NaCl concentration was 0 or 1.0 g·L-1. The phosphate-dissolving ability of the strain was the highest when using sugar as carbon source and yeast powder as nitrogen source. The strain had the greatest ability to solubilize CaHPO4 with 1304.04 mg·L-1, followed by Ca3(PO4)2 and FePO4. We found that available nutrients, leaf, stem, and root phosphorus contents in rhizospheric soil significantly increased in Ph. edulis after 180 days of inoculation with strain JXBR04. In addition, Ph. edulis inoculated with strain JXBR04 had 28.1%, 28.3%, and 51.5% higher ground diameter, seedling height, and biomass accumulation than that without JXBR04, respectively. Our findings suggested that T. aurantiacus has the potential to be applied as environment-friendly biofertilizers in maso bamboo forest in the acid soil in southern China.
    Evolutionary characteristics of soil organic carbon storage in soil plough layer under a cropland reclamation process in desert oasis
    KONG Jun-qia, DU Ze-yu, YANG Rong, SU Yong-zhong
    2019, 30(1):  180-188.  doi:10.13287/j.1001-9332.201901.037
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    The reclamation time was examined by combining field investigation and remote sensing image analysis in the Linze desert oasis area in the middle of the Hexi Corridor. Characteristics of soil organic carbon storage (SOCD) in cropland (0-20 cm) with different reclamation backgrounds were compared to understand the evolution trend of SOCD during reclamation. The SOCD of cropland (0-20 cm) varied from 2.41 to 32.97 t·hm-2, with an average of 17.22 t·hm-2. The ave-rage SOCD of cropland in saline-alkali land, Gobi and sandy land background was 19.36, 16.10, and 15.93 t·hm-2, respectively. The SOCD under three different reclamation conditions showed an increasing trend after cultivation. The cropland in sandy land and the Gobi background slowly increased after 20 years reclamation. The cropland in saline-alkali background showed a slowdown after 25 years reclamation. The SOC sequestration rates of the cropland under sandy land, Gobi and saline-alkali land background were 0.424, 0.485 and 0.811 t·hm-2·a-1, respectively. The SOCD were positively correlated with total nitrogen, total phosphorus, available nitrogen, and available phosphorus content, but had no significant correlation with available potassium and soil pH. In conclusion, the SOC sequestration rate in the saline-alkali land background was significantly higher than that in Gobi and sandy land background. However, SOCD were at a relatively low level after 30 years reclamation. Therefore, cropland management needs to be carried out for different reclamation backgrounds to improve land use efficiency and productivity in desert oasis.
    Characteristics of amino sugar accumulation in rhizosphere and non rhizosphere soil of rice under different fertilization treatments
    NING Zhao, CHEN Xiang-bi, TANG Hai-ming, GE Ti-da, HE Hong-bo, HU Jian-liang, SU Yi-rong, DENG Yang-wu
    2019, 30(1):  189-197.  doi:10.13287/j.1001-9332.201901.033
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    Soil samples were collected from paddy ecosystem under five long-term fertilization treatments, including control without fertilizer (CK), chemical fertilization alone (NPK), rice residue combined with NPK (NPKS), 30% manure plus 70% chemical fertilizer (LOM), and 60% manure plus 40% chemical fertilizer (HOM) in Ningxiang City, Hunan Province. The cha-racteristics of amino sugars accumulation in the rhizosphere and non-rhizosphere soils at rice tillering stage were analyzed. Results showed that the contents of soil organic carbon, total amino sugars and three amino monosaccharides (muramic acid, glucosamine and galactosamine) with long-term application of organic materials (rice residue or manure) were significantly higher compared with CK and NPK. The inconsistent accumulation trends of the three amino monosaccharides under different fertilization treatments indicated that different responses of microbial groups to various fertilization treatments. The content of total amino sugars was not significantly different between the rhizosphere soil and the non-rhizosphere soil, probably because the agricultural operations such as plowing could homogenize paddy soils. The contribution of amino sugar derived carbon to soil organic carbon ranged from 24.0 to 28.3 mg·g-1, which was highest in NPKS, and lowest in HOM and CK. The ratio of fungal to bacterial residues (fungal glucosamine/muramic acid) ranged from 24.4 to 36.6, indicating that fungi dominated the degradation and transformation of organic matter in all the soils. Compared with that under NPK and CK, the participation of organic matter transformation from fungi under NPKS treatment was increased, whereas the bacteria involved in organic matter transformation under HOM treatment was enhanced.
    Comparison of drought risk between transplanting and direct-sowing rice in the Sichuan Basin, China
    YANG Shi-min, GUO Xiang, WANG Ming-tian
    2019, 30(1):  198-208.  doi:10.13287/j.1001-9332.201901.021
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    The quantitative evaluation and comparison of drought risks at each development stage and the whole growth period between transplanting rice and direct-sowing rice in Sichuan Basin can provide a scientific basis for the transformation and promotion of rice production technology in various regions. Based on the theory of natural disaster risk and the formation mechanism of rice drought risk, we evaluated and compared the drought risk in the whole growth period and the four development stages (sowing-jointing, jointing-booting, booting-full heading, full heading-maturity) between transplanting rice and direct-sowing rice, analyzed the vulnerability of disaster bodies, the sensitivity of disaster environment and the capacity of drought disaster prevention and reduction of rice drought in Sichuan Basin, using meteorological data in Sichuan Basin from 1961 to 2017, the observation data of rise production, agricultural statistics and the basic geographical information. The drought risk assessment model for Sichuan Basin was established, which was used to classify the results of evaluation. The results indicated that the drought risk of rice in Sichuan Basin was higher. The medium-risk areas in terms of the two planting methods were both the most widely distributed areas. The spatial-distribution characteristics of drought risk for the two kinds of rice were generally the same which was high in the middle and east of the basin, low in the southwest of the basin, and decreased from east to west and from the center to the surroundings. For the two planting methods, the greatest difference of rice drought risk appeared at the sowing-jointing stage. The drought risk of the direct-sowing rice at the sowing-jointing stage was significantly lower, and the distribution range was smaller than that of the transplanting rice. The distribution of the slight-low drought risk area of the direct-sowing rice was wider, but the high-risk area was slightly smaller.
    Basic soil productivity in the double rice cropping system under long-term fertilization regimes in the Poyang Lake region, China
    LIU Kai-lou, HAN Tian-fu, HUANG Qing-hai, YU Xi-chu, LI Da-ming, MA Chang-bao, XUE Yan-dong, ZHANG Hui-min
    2019, 30(1):  209-216.  doi:10.13287/j.1001-9332.201901.040
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    We aimed to explore changes in basic soil productivity (BSP) under different fertilization regimes in the Poyang Lake region, Jiangxi Province, China. Soil samples were collected from a long-term fertilization experiment (since 1981) that included treatments of no fertilization (CK), chemical fertilization (NPK), and combined chemical and organic fertilization (NPKM). Then, a three-year pot experiment (from 2012 to 2014) with double rice cropping was conducted with two different fertilization regimes (no fertilization, F0; fertilization, F1) using CK, NPK and NPKM soils. Grain yield and BSP were analyzed among soils with different fertilization regimes to identify the key factors driving changes in BSP. Results showed that grain yields in NPKM soil were higher than in NPK and CK soils regardless of fertilization in the pot experiment. Under the F0 condition, annual grain yields of NPKM soil were 37.7%-143.9% and 20.8%-66.7% higher than CK and NPK soils, respectively. The BSP values of CK, NPK and NPKM soils in three years were 41.8%-53.1%, 45.2%-62.6% and 59.1%-88.1%, respectively. NPKM soil had significantly higher BSP than NPK and CK soils. Furthermore, there were significant positive correlations between soil organic matter and BSP as well as between organic carbon balance and BSP. These results suggested that long-term application of chemical and organic fertilizers could improve BSP in the double rice cropping system of the Poyang Lake region. In addition, soil organic matter and organic carbon balance are important factors for improving BSP in this region.
    Response of dry matter partitioning coefficient of summer maize to drought stress in North China
    TAN Fang-ying, LI Hao, WANG Jian-lin, WANG Zhi-wei
    2019, 30(1):  217-223.  doi:10.13287/j.1001-9332.201901.031
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    The dry matter partitioning coefficient (PC) reflects the distribution and accumulation of dry matter in crop organs. Understanding the responses of PC to drought stress is fundamental for understanding crop development under drought stress. Using field data collected under drought stress conditions during the period 2013-2015 at three sites (Xiajin, Shandong; Gucheng, Hebei; and Yuncheng, Shanxi) in North China, we quantified the effects of different drought stress intensities on the PC of stems, leaves and ears during the development stages (from emergence to jointing, from jointing to tasseling, and from tasseling to maturity). The results showed that PC of stems, leaves and ears showed significant quadratic relationships with relative soil moisture during all stages. Leaf PC was increased by 0.04-0.09 during the grain-filling stage under light and moderate drought stress, and was increased by 0.17 during the tasseling stage under sever drought stress. On the contrary, drought stress had negative effects on the ear PC. With the increases of drought stress, less dry matter was allocated to ears. Under light to severe drought stresses, ear PC was decreased by 0.08-0.34. However, no consis-tent pattern was observed for the effects of drought stress on stem PC: negative effects were observed during the vegetative growth stage and positive effects were found in the mature stage. Overall, the degree of the responses of crop PC to drought stress under different phenology stages was in the order of grain-filling stage (positive) > tasseling stage (negative) > seedling stage (negative).
    Effects of subsoiling and straw returning on soil physical properties and maize production in Yellow River irrigation area of Gansu, China
    WEN Mei-juan, WANG Cheng-bao, HUO Lin, JIANG Wan-li, YANG Si-cun
    2019, 30(1):  224-232.  doi:10.13287/j.1001-9332.201901.030
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    A field experiment was conducted to examine the effects of subsoiling 35 cm with maize straw returning, subsoiling 35 cm without maize straw returning, and rotary tillage without maize straw returning on soil compaction, soil bulk density, soil infiltration, soil water content in 0-100 cm depth, nutrients uptake and production of maize on sierozem in the Gansu Yellow River irrigated area in 2015-2017. Compared with subsoiling 35 cm without maize straw returning and rotary tillage without maize straw returning, subsoiling 35 cm with maize straw returning significantly decreased the soil compaction and soil density in 0-40 cm depth. Compared with that in 2015 (before experiment), soil compaction and soil bulk density in subsoiling 35 cm with straw returning was decreased by 42.6% and 7.0%, respectively, after harvest in 2017. Compared with other treatments, subsoiling 35 cm with straw returning had the lowest variation of soil compaction (6.1%) and soil bulk density (3.2%) in 0-40 cm depth before sowing and after harvest in 2016 and 2017. The soil infiltration rate in subsoiling 35 cm with straw returning was significantly improved by 33.6% compared with rotary tillage without maize straw returning. Subsoiling 35 cm with straw retention could significantly increase soil water content and decrease water variation in 0-100 cm soil depth in spring (before maize sowing) and autumn (after maize harvest). Compared with rotary tillage without maize straw returning, water storage in subsoiling 35 cm with straw retention was increased by 15.5% and 5.6% in spring and autumn, respectively. The water use efficiency was enhanced by 32.4%. Furthermore, subsoiling 35 cm with straw retention could increase maize economic yield and biomass yield by 25.6% and 33.3%, compared with rotary tillage without straw retention. Subsoilng and straw retention could promote nutrient absorption, with N, P2O5 and K2O uptake increased by 49.6%, 51.5% and 37.6%, compared with rotary tillage. Overall, our results suggested that subsoiling 35 cm straw retention could improve soil characteristics, stabilize the phy-sical properties of the plough layer, increase soil water content in the 0-100 cm soil layer, and reduce water variation in spring and autumn. Consequently, it was the best management to promote the water and nutrient utilization of maize and achieve high yield. Our findings could provide theoretical basis for further research on the construction technology of the plough layer in Gansu irrigation area.
    Influencing factors and their simulation of summer maize land surface-air temperature difference under drought conditions
    LIU Er-hua, ZHOU Guang-sheng
    2019, 30(1):  233-242.  doi:10.13287/j.1001-9332.201901.039
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    Crop water deficit status characterized by land surface-air temperature difference (Ts-Ta) has been widely investigated. However, empirical evidence for characteristics and impact factors of Ts-Ta considering the process of crop growth are less yet, which restricts the accurate simulation of Ts-Ta. Here, the data of Ts-Ta during the process of maize growth were obtained from five irrigation water control experiments after the period of summer maize 3-leaf stage in 2014 and jointing stage in 2015. The results showed that Ts-Ta of summer maize cropland was significantly affected by soil water content. Ts-Ta increased with the deficit of soil water. During summer maize water treatments, the normalized difference vegetation index (NDVI) was the main impact factor of Ts-Ta, with a significant linear relationship. However, during different growth stages, some additional factors including meteorological, biological and soil factors could also affect Ts-Ta, including canopy photosynthetic active radiation absorption ratio (fAPAR) after 3-leaf stage, relative soil water content (RSWC), and air relative humidity (RH) from 3-leaf stage to jointing stage. Then, the growth duration simulation model of Ts-Ta, vegetative growth simulation model of Ts-Ta and reproductive growth simulation model of Ts-Ta were established in terms of the data in 2014. Those simulation models were validated based on the experimental data of five irrigation water treatments after summer maize jointing stage in 2015. The results showed that the growth duration simulation mode of Ts-Ta could explain 63% variation of Ts-Ta in 2015. However, 79% variation of Ts-Ta could be explained by the simulation results of the vegetative growth simulation model of Ts-Ta and the reproductive growth simulation model of Ts-Ta. The results provided the basis for the quantitative evaluation of crop drought based on Ts-Ta.
    Application effects of biogas slurry partly substituting for chemical fertilizer on autumn tomato production in winter-solar greenhouse
    WANG Jing-quan, GU Duan-yin, YU Xiao-dong, CUI Xiu-min, LOU Yan-hong, CHU Yu, WANG Chun-lan, ZHUGE Yu-ping
    2019, 30(1):  243-250.  doi:10.13287/j.1001-9332.201901.035
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    To explore the effects of biogas slurry coordinating chemical fertilizer on growth promotion of tomato, we used three kinds of typical biogas slurry as concentrated nutrient solution, respectively fermented from raw duck manure, pig manure, cow dung, while urea, monocalcium phosphate and potassium sulphate as auxiliary nutrition to balance the nutrient difference between different dilution ratios of biogas slurry. The results showed the biogas slurry partially substituting chemical fertilizer could significantly improve soil fertility, including available nitrogen, phospho-rus, and potassium. As for water soluble calcium, magnesium, iron, manganese and zinc in soil, biogas slurry application could activate their availability, with the magnitude of such effects depended on the fermentation level of raw materials and dilution ratio. Compared with chemical fertilizer, coordinating biogas liquid fertilizer significantly promoted the growth of tomato, with the yield increased by 55.9%-232.8% and the chemical fertilizer dosage decreased by 18.2%-85.0%. Furthermore, such effects became more prominent along with prolonged time. The fruit quality was significantly improved with the increases of lycopene, ascorbic acid and total sugar, and the decreases of acidity and nitrite concentration, and the decrease of NO2- by 35.6%-90.3%. In addition, the taste flavor of fruits was 7.0%-20.3% higher than that of chemical fertilizer treatment. The yield and quality of tomato took on nonlinear synchronization, and the relation between taste flavor and sugar/acid showed significantly positive correlation, which was affected by fertilizer type. Biogas slurry partly substituting chemical fertilizer could achieve the goals of high yield, high quality, environmental protection, efficient utilization of agricultural resources in tomato production.
    Effects of light quality on carbon-nitrogen metabolism, growth, and quality of Chinese chives
    NING Yu, AI Xi-zhen, LI Qing-ming, BI Huan-gai
    2019, 30(1):  251-258.  doi:10.13287/j.1001-9332.201901.032
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    We examined the effect of white + red (WR), white + blue (WB), white + green (WG), white + purple (WP) on the carbon-nitrogen metabolism, growth and quality of Chinese chives, with ‘Pingjiu 2’ as the material and white light (W) as the control. The results showed that photosynthetic rate (Pn) in WR treatment was significantly higher than that in the control (CK) and that there was no difference among WB, WG, WP and CK. The activity of RuBPCase in all the four treatments was higher than that in CK. Compared with other treatments, WR showed the highest total sugar content, then WP, with WB and WG showing the lowest. Compared with CK, sucrose phosphate synthase (SPS) activity in WR was higher, and lower in the other three treatments, especially the lowest in WB. WB showed the highest activity of sucrose synthetase (SS) and amylase (AMS), WR displayed the lowest as well as the similar or lower in WG or WP compared with CK. These results implied that the increases of the proportion of red and purple light could improve carbon assimilation and transformation and thus accelerate sugar accumulation of Chinese chives. The content of total nitrogen, protein nitrogen, the activities of NR, GS and GOGAT of WB were the highest among all the treatments. The GDH activity of WB was the lowest and notably lower compared with CK. WR showed the lower contents of total nitrogen, protein nitrogen, the activities of NR and GS, and higher activities of GOGAT and GDH than those in CK, while the GDH activity of WR was the highest. WG showed lower total nitrogen, no-protein nitrogen content, and GDH activity, but higher protein nitrogen, NR and GOGAT activities than those in CK. Compared with the control, WP showed the similar results as WG, besides the higher GS activity, with most of these parameters in WP being better than in WG. These results indicated that blue, purple and green light could promote nitrogen metabolism, while red light might inhibit protein synthesis in Chinese chives. The growth of Chinese chives was much better under red and purple light, but worse under blue light, which led to thinner leaves and lower growth mass. Chinese chives of WP with the lowest crude fiber content showed the optimal comprehensive quality. Therefore, purple light exhibited the best effect on the growth of Chinese chives.
    Changes of growth and yield characters of five varieties (lines) of tea-applied chrysanthemum under different planting dates and pinching patterns
    LUAN Xin-sheng, CHEN Fa-di, FANG Wei-min, SHI Ya-dong, ZHAO Shuang, CHEN Su-mei, ZHANG Fei, GUAN Zhi-yong
    2019, 30(1):  259-265.  doi:10.13287/j.1001-9332.201901.036
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    To identify the high yield planting date and pinching pattern, we compared the yields of five new varieties (lines) of tea-applied chrysanthemum, the ‘Suju 10’, ‘Suju 12’, ‘Suju 13’, ‘CH1-44’ and ‘CH5-13’. A field experiment with split-split plot design was carried out. The main plot treatments including three (early, middle and late) planting dates, split-plot treatments including 5 new varieties (lines), and split-split-plot treatments including four different kinds of pinching schemes. The results showed that the yield of ‘CH5-13’ and ‘Suju 13’ was relatively higher among the five varieties (lines), followed by ‘CH1-44’ and ‘Suju10’, and ‘Suju 12’ showed the lowest yield. Among the five varieties (lines), planting date on May 27th and two-time pinching treatments showed the highest values of plant height, crown width, flower number, flower diameter, fresh mass, yield per plant and yield per unit area. Compared with the planting date on May 7th and June 13th, the above indexes increased by 16.0% and 19.0%, 18.0% and 22.8%, 36.7% and 42.2%, 11.1% and 2.3%, 13.0% and 4.0%, 47.8% and 36.6%, 48.5% and 36.7%, respectively. With the pinching time postponed, plant height decreased. Compared with the no pinching treatment, plant height of the two-time pinching treatment decreased by 50.2%, and values of crown width, flowers number, the flower fresh mass, the yield per plant and the yield per unit area were highest, with increases of 17.0%, 29.1%, 5.5%, 34.0% and 34.8%, respectively. The impact performance of three main factors on the growth and yield of the tea-applied chrysanthemum was in order of planting date>varieties>pinching time.
    Low-carbon behavioral performance of scenic spots and the driving mechanism: A case study of Zhangjiajie World Heritage Site.
    WANG Kai, GAN Chang, OU Yan, LIU Hao-long
    2019, 30(1):  266-276.  doi:10.13287/j.1001-9332.201901.020
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    Low-carbon behavior of scenic spots has direct influence on coordinated and orderly development of eco-environment and socio-economic system in World Heritage Site. Five level-one indicators and 38 level-two indicators were respectively established to systematically measure the low-carbon behavioral performance (LCBP) of scenic spots in Zhangjiajie, the seat of “World Natural Heritage”. ANOVA and Bonferroni analysis were applied to compare the LCBP of scenic spots in different groups. The redundancy analysis and Monte Carlo permutation were used to figure out the main driving factors that affect scenic area’s LCBP. Results showed that 32 scenic spots’ LCBP was excellent in general, with a weighted mean value of 3.10. The group mean of perfor-mance in low-carbon design, daily energy conservation, water saving management, waste reduction and low-carbon awareness was 0.49, 0.74, 0.24, 1.51 and 0.11, separately. Huanglong Cave performed the best (4.193) and He Long’s Former Residence performed the worst (2.400) in the 32 scenic spots. The scores of 5A, 4A and 3A or no A scenic spots showed no significant difference in most low-carbon behavior indicators, only 11 indicators reflected significant difference among diffe-rent groups. Pressures from investors, administration committee, tourists and local government were main driving factors for low-carbon behavior of scenic spots.
    Ecological quality assessment of Xiongan New Area based on remote sensing ecological index
    YANG Jiang-yan, WU Tian, PAN Xiao-yan, DU Hai-tong, LI Jin-lu, ZHANG Li, MEN Ming-xin, CHEN Ying
    2019, 30(1):  277-284.  doi:10.13287/j.1001-9332.201901.017
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    The continuous urbanization leads to increasing pressure on the ecological environment. It is a key point to measure regional ecological environment quality objectively, accurately and quickly from multiple directions in ecological research. In this study, the normalized vegetation index (NDVI), wet index (WET), land surface temperature (LST), and normalized difference building-soil index (NDBSI) were extracted from the aspects of greenness, humidity, heat and dryness. The ecological quality of Xiongan New Area between 1995 and 2015 was evaluated by integrating selected indicators to measure the remote sensing ecological index (RSEI) with principal component analysis technology based on ENVI platform. The results showed that the average RSEI of Xiongan New Area was 0.724, 0.710, and 0.682 in 1995, 2004 and 2015, respectively, showing a downward trend. RSEI mainly changed from 4, 5 to 1, 2 and 3 in the study area from 1995 to 2015. Ecological quality improved and deteriorated area accounted for 8.9% and 20.9% of the total area respectively. The ecological quality improved area was mainly located in the east and south of Xiongxian County, because a large area of forests and gardens was highly valued and strictly protected by the local government. The ecological quality deteriorated area was in the periphery of the town and the surrounding area of Baiyangdian due to the sharp decline of the water area of Baiyangdian and the continuous urbanization. The three-year average correlation coefficient between RSEI and each component index was 0.804, which was higher than that between other component indices. Our results showed that RSEI could efficiently integrate the information of each component index and comprehensively and accurately reflect the ecological quality of the study area.
    Fractional vegetation cover change based on vegetation seasonal variation correction: A case in Lianjiang County, Fujian Province, China
    YANG Hui-ting, XU Han-qiu, SHI Ting-ting, CHEN Shan-mu
    2019, 30(1):  285-291.  doi:10.13287/j.1001-9332.201901.016
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    Remote sensing change detection based on fractional vegetation cover (FVC) has become an important way in the research of vegetation and related ecosystems. It is difficult to meet the requirement for optical remote sensing in subtropical areas because of cloudy/rainy weather conditions. Using images from different seasons in the vegetation change detection will inevitably lead to errors in the change detection results due to the seasonal difference. To overcome this problem, we proposed a method for correcting vegetation seasonal variations by taking advantage of high temporal resolution advantage of MODIS remote sensing data and the high spatial resolution of remote sensing data. Based on the relationship between MODIS vegetation data in different seasons via regression analysis, we transformed the vegetation information of the high resolution images of corresponding years to the required season of the years. The method was applied in the Aojiang basin area of Lianjiang County in Fujian Province, China, with good results of vegetation information transformation. The results showed that after transforming vegetation information of the 2007 winter scene and 2013 spring scene of high resolution images to those of summer season, the FVC was enhanced from 66.5% to 79.7% for 2007, and from 58.6% to 77.9% for 2013. Our method effectively removed the seasonal difference of FVC and improved the accuracy of the FVC-based change detection results.
    Patterns of bird nocturnal migration at Shenyang Taoxian International Airport, Northeast China
    WANG Ying, SHI Yuan, JIN Lin-yu, GUAN Shuang, HUANG Zi-qiang, HAO Heng-yu, WAN Dong-mei, LI Dong-lai
    2019, 30(1):  292-300.  doi:10.13287/j.1001-9332.201901.008
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    The high frequency of bird strikes at night during the migration season is a remarkable characteristic of bird strikes at airports. Understanding the nocturnal migration patterns of birds is important for improving the methods to prevent bird strikes at night. In this study, we combined the methods of mist-net capture and sound recording to examine the composition of bird species and the patterns of nocturnal migration at Taoxian Airport. We found that 56 species of birds (88.9% of the total) migrated at night and mainly migrated after midnight. There were obvious temporal dynamics and sequence in migration. The time of spring migration was more concentrated and the migration peaked in mid-May, with Coturnix japonica, Lanius cristatus, Emberiza fucata, Saxicola torquatus, Caprimulgus indicus and Phylloscopus inornatus as the dominant species. The migration pattern was more dispersed in autumn and the peak of migration was in late September to early October, and the main species were C. japonica, Turdus hortulorum, Anthus cervinus, Scolopax rusticola, Locustella lanceolata and Emberiza spodocephala. Based on the Bird Hazard Risk Assessment, there were mainly two species with high risk (C. japonica and L. cristatus) in spring migration and four species with high risk (C. japonica, Athene noctua, T. hortulorum and S. rusticola) in autumn migration. We proposed several strategies for the prevention of bird strike based on the composition of migratory birds, migration dynamics, migration rhythm and species risk level, which could serve as references for bird strike prevention at Taoxian Airport.
    Effects of environmental factors on the distribution of amphibians in agricultural landscape
    LIANG Guo-fu, LI Cheng-xi, BAI Xin, XU Hai-xiang, DING Sheng-yan
    2019, 30(1):  301-308.  doi:10.13287/j.1001-9332.201901.008
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    We analyzed the relationship between the distribution of amphibians and the environmental variables at the habitat level and landscape level in Fengqiu County of Henan Province, a typical region of the lower reaches of the Yellow River, with the support of geographic information system (GIS) and R software. At the habitat level, dissolved oxygen (DO), conductivity (COND), turbidity (TURB), NH3-N, pond-interior vegetation cover (VEGinterior), emergent vegetation cover (EMER), pond-edge vegetation cover (VEGedge), benthic fauna predators (PRE), and pond area (AREA) were selected as habitat variables. At the landscape level, total area of ponds (AP), distance to the nearest road (DR), total area of farmlands (AF), total area of woodlands (AW), Shannon’s diversity index (SHDI), and contagion index (CONTAG) were selected as explanatory variables, calculated within a buffer of 250, 500, 1000 and 2000 m around the centroid of each pond. The results showed that the distribution of Bufo gargarizans was mainly related to the PRE and landscape variables within the larger radius buffer zone (AW2000, DR2000, SHDI1000, CONTAG1000). The distribution of Pelophylax nigromaculata was closely related to the EMER and landscape variables within the smaller radius buffer zone (SHDI500). VEGinterior and PRE were the key factors determining the distribution of Pelophylax plancyi. Landscape variables (AF2000, SHDI2000) within the larger buffer radius were the most significant influencing factors on Fejervarya multistriata. For all amphibian species, the EMER and SHDI500 were variables that should be considered. For the protection of amphibian species in plain agricultural landscape, we suggested that conservation efforts should focus on improving the pond-interior vegetation cover, protecting the semi-permanent ponds, and enhancing the functional connectivity among ponds.
    Vertical change of cladoceran ephippial densities in the sediments of Lake Nanyi and its correlation with the nutrients
    HU Jin-ting, ZHANG Kun, HE Ping, LI Xiao-ming, JI Lei, ZHOU Zhong-ze
    2019, 30(1):  309-315.  doi:10.13287/j.1001-9332.201901.006
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    We examined the vertical variations of cladoceran ephippia in the sediments (1-28 cm) of Lake Nanyi. Nine cladoceran ephippia (Daphnia similoides sinensis, Daphnia galeata, Daphnia pulex, Ceriodaphnia sp., Moina micrura, Bosmina sp., Scapholeberis sp., Leydigia leydigii and Chydorus sp.) were identified. The ephippial densities of Daphnia species and small cladocerans ranged from 0 to 2.0 ind·g-1 DM and from 0 to 10 ind·g-1 DM, respectively. D. similoides sinensis and Ceriodaphnia sp. were respectively dominant species of large and small cladocerans in the sediments of Lake Nanyi. The ephippial densities of D. similoides sinensis had a significant negative correlation with total phosphorus content of sediments in the 1# sampling site of Lake Nanyi and had positive correlations with total nitrogen and total phosphorus contents in the 3# sampling site. In three sampling sites (except for total nitrogen contents in the 2# sampling site), there were significant positive relationships between the ephippial densities of Ceriodaphnia sp. and both total nitrogen and total phosphorus contents. Our results suggested that eutrophication and fish predation affected the historical succession of cladoceran community structure in Lake Nanyi.
    Reviews
    Research progress on the effects of atmospheric nitrogen dioxide on plant growth and metabo-lism
    WANG Yue, TENG Zhi-yuan, ZHANG Xiu-li, CHE Yan-hui, SUN Guang-yu
    2019, 30(1):  316-324.  doi:10.13287/j.1001-9332.201901.028
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    Nitrogen dioxide (NO2) is one type of the atmospheric nitrogen oxides, which is the main component of atmospheric aerosol particles. Reducing the concentration of atmospheric NO2 can decrease the haze in the air. Atmospheric NO2 deposits on plant leaves by both dry and wet deposition. After leaf absorption, atmospheric NO2 was reduced by two metabolism ways: one was the nitrogen metabolism by reductase mainly in cytoplasm and chloroplast, and the other was the pathway of NO2 decomposition reaction in the apoplast and cytoplasm. Plant absorption of NO2 disturbs plant normal growth and physiological metabolism, including vegetative growth and reproductive growth, nitrate reductase (NaR) activity, nitrite reductase (NiR) activity, nitrogen uptake, photosynthetic and other physiological metabolic processes. Here, we reviewed the research progress on the effects of atmospheric NO2 on plant growth and metabolism, and proposed the future research direction of physiological and molecular mechanism of atmospheric NO2 absorption by plants.
    Sustainability science revisited: Recent advances and new opportunities
    ZHOU Bing-bing, MA Qun, WU Jian-guo, HU Guo-hua, MAO De-hua, ZENG Xiao-ji, GUO Jie, FANG Xue-ning, LIU Yu-peng, LYU Li-gang
    2019, 30(1):  325-336.  doi:10.13287/j.1001-9332.201901.001
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    During the past decade, sustainability science has rapidly developed into a globally well-recognized and important new science of the 21st century. However, sustainability science has not received much attention from scientists and practitioners in China where sustainable development and ecological civilization have been prominent themes. To promote the development of sustainability science in China, Wu, et al. (2014) published the first in-depth review on the subject in Chinese, entitled “What is sustainability science?” Here, we revisit the question, and discuss the relationship between sustainability science and sustainable development research, the scientific paradigm and the core research questions of sustainability science. Our review of the recent advances in this field reveals contrasting trends for the world versus China. On the one hand, the world is witnessing sustainability science maturing with global momentum to systematically advance sustainability research and education. On the other hand, China greatly lags behind developed countries and South Africa, albeit the great deal of new passion and desire for sustainable development. To promote the science and practice of sustainability in China, we propose a trinity strategy: 1) “bringing in” from the global community to guide Chinese practices in sustainable development; 2) “reaching out” to the global community to share Chinese wisdom of sustainable development; and 3) “integrating traditional Chinese philosophy with western science” to lead the development of sustainability science.
    Research progress on the effects of freeze-thaw on soil physical and chemical properties and wind and water erosion
    SUN Bao-yang, LI Zhan-bin, XIAO Jun-bo, ZHANG Le-tao, MA Bo, LI Jian-ming, CHENG Dong-bing
    2019, 30(1):  337-347.  doi:10.13287/j.1001-9332.201901.019
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    Freeze-thaw erosion, one of the main types of soil erosion, is widely distributed in China. The distribution and harm of the combined erosion of freeze-thaw and other forces were greater than freeze-thaw erosion. We reviewed related research progress of the effects of freeze-thaw on soil phy-sical and chemical properties, wind erosion, and water erosion, based on literatures from China and abroad. Under the condition of freeze-thaw, soil water was transported and soil structure was dama-ged. Soil porosity, bulk density, shear strength, aggregate stability and organic matter were all changed. The change tendency and amplitude were related to soil texture and the degree of freeze-thaw. The occurrence and process of soil wind erosion and water erosion were influenced by the condition of freeze-thaw. Soil erodibility and erosion intensity increased as a result of the changes of soil physical and chemical properties. At present, the research on freeze-thaw mainly based on indoor simulation, which was quite different from the actual freeze-thaw process in the field. The conclusions obtained were not unified or even contrary due to different test conditions. Therefore, through combining indoor simulation and field survey, to strengthen the research of soil erosion mechanism of freeze-thaw conditions was the focus of the future research, which was of great significance for forecasting and preventing of soil erosion in the periods of thawing and the regions of seasonal freeze-thaw.
    Molecular sequestration mechanisms of heavy metals by iron oxides in soils using synchrotronbased techniques: A review
    XIA Xing, YANG Jian-jun
    2019, 30(1):  348-358.  doi:10.13287/j.1001-9332.201901.012
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    Iron oxides, widely distributed in soils, have large specific surface areas and strong affinity to heavy metals, and thus play a significant role in the transformation of heavy metals in soils. To understand the environmental behaviors of heavy metals and assess their bioavailability in contaminated soils, it is important to investigate the sequestration mechanisms of heavy metals by iron oxides. The traditional methods, including adsorption modeling and chemical extraction fractionation, have obvious limitations and provide little information on the sequestration mechanisms of heavy metal by iron oxides at the molecular level. The application of synchrotron-based techniques in environmental soil science has greatly enhanced the molecular-level understanding of the immobilization mechanisms of heavy metals by iron oxides under various environmental conditions. Here, we reviewed the development of synchrotron-based techniques and summarized the molecular sequestration mechanisms of heavy metals by iron oxides in model and real soil systems under various environmental factors. The future development of synchrotron-based techniques and their applications were prospected.