Table of Content

10 April 2025, Volume 44 Issue 4

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Dynamics of calcium and magnesium storage in plant litter and sediments of a subtropical forest headwater stream.

MA Diting, ZHAO Zemin, HU Wanrong, PENG Yan, YUAN Chaoxiang, NI Xiangyin, WU Fuzhong, YUE Kai

2025, 44(4):  1057-1064.  doi:10.13292/j.1000-4890.202504.029

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Plant litter and sediments play a crucial role in the storage and migration of nutrients in forest headwater streams, and can significantly impact material cycling in downstream waters. We examined the spatial and temporal dynamics of calcium (Ca) and magnesium (Mg) concentrations and storage in plant litter and sediments of a subtropical forest headwater stream from March 2021 to February 2022 in the upper reaches of Minjiang River, Sanming, Fujian. Results showed that: (1) The maximum concentrations of Ca and Mg in plant litter were 15557.72 and 970.98 mg·kg^-1 in December and October, respectively. The highest concentrations of sediment Ca and Mg were 1840.61 and 576.74 mg·kg^-1 in August and May, respectively. (2) The highest storage of plant litter Ca and Mg was observed in April, with average values of 1.27 and 0.09 g·m^-2, respectively, while those of sediment Ca and Mg occurred in August and May, with average values of 130.76 and 46.77 g·m^-2, respectively. (3) The largest storage of plant litter Ca and Mg occurred in the source reach, whereas that of sediments occurred in a sampling site with confluence at the middle-lower reaches of the stream. (4) Stream physical and chemical properties, particularly discharge, water temperature, monthly rainfall, rainfall frequency, and dissolved oxygen, significantly affected the storage and concentrations of Ca and Mg in plant litter and sediments. These results will help to better understand the role of forest headwater streams in nutrient storage and fluxes in subtropical forests.





Spatial distribution pattern and interspecific correlation of main dominant species of evergreen and deciduous broad-leaved mixed forest in Cenwanglaoshan Mountain.

LIANG Huolian, CHEN Tao, LUO Yinghua, TAN Xiang

2025, 44(4):  1065-1075.  doi:10.13292/j.1000-4890.202504.026

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The study of species spatial distribution patterns and interspecific correlation dynamics is helpful to understanding community development and the mechanisms underlying spatial distribution. In this study, 10 dominant tree species of a 1 hm² evergreen and deciduous broad-leaved mixed forest in Cenwanglaoshan were used to assess community spatial heterogeneity by the L(r) function. The spatial distribution pattern and interspecific correlation of dominant populations in 2015 and 2022 were analyzed by univariate model and binary model of pairwise correlation function g(r). Moreover, the pattern of tree mortality was analyzed. The results showed that: (1) The community habitats were homogenous, and adult trees showed a random distribution. (2) With the complete spatial randomness model as the null model, 10 dominant species showed aggregated distribution, which gradually changed to random distribution with increasing scale. The aggregate distribution scale of Rhododendron simiarum increased during the 7-year period. The random distribution scale of other dominant species increased, but the main distribution types did not change. (3) With the complete spatial randomness model as the null model, dominant species either showed no interspecific correlation or positive correlation. During the 7-year period, there was an increase in scale of no correlation for 33 pairs of dominant species, while the scale of positive or negative correlation decreased for 37 pairs of dominant species. (4) The dead trees of seven dominant species showed no correlation with living trees at all scales, while the dead trees of other three species showed no correlation with living trees at most scales. In conclusion, there was no competition among the dominant species in the community during the 7-year period. Random death was the main pattern of dominant species. The dominant species tended to be randomly distributed, and the interspecific relationship was mainly non-correlation or positive correlation. The development of the community was relatively mature and the structure tended to be stable.





Woody species composition and habitat association of the 20 hm² plot of subalpine cold-temperate coniferous forest in Shangri-La, Yunnan.

GU Rong, WAN Jiamin, CHEN Mingmiao, ZHANG Caicai, LIN Luxiang

2025, 44(4):  1076-1084.  doi:10.13292/j.1000-4890.202504.024

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Abies georgei forests represent one of the major community types of subalpine cold-temperate coniferous forests in the Hengduan Mountains, which forms alpine treeline in southwest China. This study is based on survey data from the  a 20 hm² plot in subalpine coldtemperate coniferous forest of the Shangri-La National Park in Yunnan Province. We investigated species composition, diameter class structure, and habitat preference of woody species with diameter at breast height (DBH) ≥1 cm. The results showed that: (1) A total of 39106 independent individuals and 9888 branches belonging to 10 families, 15 genera and 28 species were tagged. Among them, there were 27463 individuals of A. georgei, accounting for 70% of total individuals. (2) The areal type of the family and genera predominantly represented the north temperate and its two varieties, accounting for 50% and 87%, respectively. (3) The diameter class distribution of dominant species A. georgei, Rosa omeiensis and Sorbus rehderiana exhibited an inverse J-shaped pattern, indicating a good natural regeneration. Lonicera tangutica, Dipelta yunnanensis, and Rhododendron rubiginosum exhibited a skew-normal distribution, indicating stable population structure. (4) Among the 22 targeted species with individuals ≥20, 10 species were significantly positively or negatively associated with at least one specific habitat (i.e., gully, low slope, high slope, and high valley). Among them, four species, including R. rubiginosum and D. yunnanensis, showed a positive association with high-slope habitat. Two species, Picea likiangensis and Cotoneaster acutifolius, showed a positive association with low-slope habitat. A. georgei was positively associated with high-valley habitat, while three species, including R. rubiginosum, S. rehderiana, and D. yunnanensis, exhibited a negative association with high-valley habitat. These findings suggest that the niche differentiation of habitats plays an important role in maintaining species diversity in the A. georgei forest at local scale. Our results provide a basis for future research on the mechanisms of community assembly and species coexistence in subalpine cold-temperate coniferous forests.





Asymmetric competition in natural forests at different successional stages in the Daxing’an Mountains, China.

XIAO Yunyou, DONG Lingbo

2025, 44(4):  1085-1096.  doi:10.13292/j.1000-4890.202504.022

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Asymmetric competition plays a crucial role in the spatial distribution of populations, community structure transitions, and stable forest succession. Based on survey data from fixed 1hm2 plots in each of three different succession stages (Betula platyphylla forest, B. platyphylla-L. gmelinii mixed forest, and Larix gmelinii forest) in Daxing’an Mountains, we quantified the spatial distribution and competition asymmetry of different tree species (Betula platphylla and Larix gmelinii) and different size classes (saplings, medium trees, and large trees) using univariate and bivariate pair-correlation functions g(r) and univariate and bivariate mark variogram γ(r). The results showed that dominant tree species exhibited significant aggregated distribution at multiple scales. Symmetric competition was mainly found within species. Significant asymmetric competition was only found at the 0-1 m scale in the Betula forest. In the mixed forest, there was a significant symmetric competition between Betula and Larix at the 2-3 m scale, with spatial negative correlation at the 0-3 m scale. As tree size increased, the spatial distribution patterns of trees in each successional stage showed a transition from clustered distribution in saplings to random distribution in large trees. In Betula forest, individuals of the same and different classes mainly exhibited symmetric competition, with asymmetric competition only found between medium and large trees at the 10-12 m scale. The spatial correlation between size classes was mainly negative and uncorrelated. In the mixed Betula-Larix forest, only saplings showed significant asymmetric competition at the 10 m and 20 m scales. Large trees exhibited significant symmetric competition with medium and sapling trees, with positive spatial correlations between size classes. In Larix forest, individuals within and among different classes primarily engaged in symmetric competition, with significant asymmetric competition between saplings and large trees at multiple scales, and the spatial correlations between classes were mainly unrelated. Symmetric competition within the same species and size classes was an important factor influencing the spatial distribution patterns of trees in natural forest communities at different successional stages.





Carbon density and carbon sequestration potential of rubber plantations under different compound management patterns in Hainan Island.

YU Lei, LU Wen, SONG Peihong, YANG Qiu, YANG Huai, LIU Wenjie, LUAN Junwei, LIU Shirong

2025, 44(4):  1097-1103.  doi:10.13292/j.1000-4890.202504.042

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Addressing the urgent need to transform rubber plantations pattern in Hainan Island and solve the problem of enhancing ecosystem carbon density in rubber plantations under compound management patterns, seven typical compound management patterns of rubber plantations in Hainan Island were selected as research objects, including Hevea brasiliensis + Michelia macclurei, Hevea brasiliensis + Alpinia oxyphylla, Hevea brasiliensis + Alpinia katsumadai, Hevea brasiliensis + Pandanus amaryllifolius, Hevea brasiliensis + Theobroma cacao, Hevea brasiliensis + Coffea arabica, and Hevea brasiliensis + Cinnamomum cassia. The results showed that: (1) Compared with pure rubber plantations, ecosystem carbon density of rubber plantations under compound management patterns in Danzhou and Wenchang were significantly increased. (2) In Danzhou, ecosystem carbon density under compound management patterns followed the order of Hevea brasiliensis + Cinnamomum cassia pattern (213.3 ± 9.45 t·hm^-2, with a carbon sequestration potential of 19.73 t·hm^-2); Hevea brasiliensis + Alpinia oxyphylla pattern (201.51±15.29 t·hm^-2, with a carbon sequestration potential of 7.94 t·hm^-2), Hevea brasiliensis + Pandanus amaryllifolius pattern (200.37±9.60 t·hm^-2, with a carbon sequestration potential of 6.80 t·hm^-2), and Hevea brasiliensis + Coffea arabica pattern (199.23±8.46 t·hm^-2, with a carbon sequestration potential of 5.66 t·hm^-2). (3) In Wenchang, ecosystem carbon density of rubber plantations under the Hevea brasiliensis + Michelia macclurei pattern was significantly increased (198.07±18.37 t·hm^-2, with a carbon sequestration potential of 38.76 t·hm^-2). These results provide a theoretical basis and technical support for forest transformation and carbon sequestration of rubber plantations under compound management patterns in tropical areas.





The impacts of exogenous IAA and 6-BA on biomass allocation and allometric growth relationships in stumping seedlings of Pinus yunnanensis.#br#

CHENG Sili, GU Xuesha, HU Zhaoliu, TANG Guangpeng, HE Bin, CHEN Lin, CHEN Shi, XU Yulan, CAI Nianhui

2025, 44(4):  1104-1113.  doi:10.13292/j.1000-4890.202504.027

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We investigated biomass allocation and allometric growth of Pinus yunnanensis seedlings in response to exogenous indole-3-acetic acid (IAA) and 6-benzylaminopurine (6-BA). Three levels of IAA (0, 150, 300 mg·L^-1) and three levels of 6-BA (0, 100, 200 mg·L^-1) were combined in pairs and total nine treatments were set up to measure biomass of P. yunnanensis seedlings under different combinations of IAA and 6-BA treatments. The standard major axis (SMA) regression analyses were employed to explore the allometric growth relationships among different organs of P. yunnanensis seedlings under different treatments. The results showed that different treatments did not affect biomass accumulation and allocation among various organs of P. yunnanensis seedlings compared to the control (J1) (P>0.05). High concentration IAA and medium concentration 6-BA (J8) treatment favored biomass accumulation in roots and stems. High concentration IAA and 6-BA treatment (J9) prioritized resource allocation to stems. Medium concentration IAA treatment (J4 and J6) prioritized resource allocation to leaves. The impact of different treatments on root, stem and leaf biomass varied in order: combined IAA and 6-BA treatment > single 6-BA treatment > single IAA treatment. The impact of different treatments on aboveground and total biomass accumulation followed an order: single IAA treatment > combined IAA and 6-BA treatment > single 6-BA treatment. The allometric growth relationships among different organs varied under different treatments. Among them, J6, J7, and J9 treatments generally showed allometric growth, while other treatments mostly exhibited isometric growth. Our results suggested that the combined application of IAA and 6-BA was more effective than the single application. The allometric growth relationships varied under different treatments, exhibiting both isometric and allometric growth, which reflected the different growth strategies of P. yunnanensis seedlings.





Diurnal and nocturnal water use characteristics and the response to meteorological factors in Salix psammophila during the summer drought period.

SUN Kai, PEI Zhiyong, HAO Yijun, WANG Haichao, SUN Xiaotian, YANG Jianjun, WANG Xinping1, HAN Zhaomin

2025, 44(4):  1114-1124.  doi:10.13292/j.1000-4890.202504.048

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To gain deep insights into shrub water use patterns and its response mechanism to environmental changes, it is essential to investigate the strategies of diurnal and nocturnal water use ratio by Salix psammophila under different moisture conditions. Three irrigation treatments were set in summer drought periods, including full irrigation (T₂₅, irrigated when the soil water potential at 20 cm directly below the dripper reached -25 kPa), water-controlled irrigation (T₅₀, irrigated when the soil water potential at 20 cm directly below the dripper reached -50 kPa), and no irrigation (CK, control). Environmental factors and the rate of sap flow in branches from different orientations were synchronously and continuously monitored. Plant water use was calculated based on the extension of branch base diameter in typical S. psammophila artificial forest of Hobq Desert. Results showed that there was a significant advantage in sap flow in the north direction of S. psammophila under T₂₅, and no significant advantage under other treatments. During the summer drought periods, the daytime water use (Q_d) and nocturnal water use (Q_n) of group T₂₅ increased by 255.6% and 72.7%, respectively, and the proportion of Q_n reduced from 4.0% to 2.0%. There was a significant positive correlation between the Q_d of T₂₅ and soil moisture (θ) of the 0-40 cm soil depth (P≤0.01). There was a significant negative correlation between Q_n and θ in the 40-60 cm soil layer (P≤0.05). The correlation between Q_d and Q_n in the controlled irrigation group and θ was not significant. The effects of vapor pressure deficit and relative air humidity on Q_d and Q_n decreased with increasing θ. Precipitation positively affected Q_n by increasing soil moisture (P≤0.05). We concluded that water use of S. psammophila can be derived well from the branch diameter, which was less affected by the branch orientation. The diurnal and nocturnal water use of S. psammophila was 0.27 to 0.96 mm·d^-1 and 0.009 to 0.019 mm·d^-1, respectively, indicating different adaptation to short-term and long-term soil moisture supply. Full irrigation did not alter the nocturnal water use habits of S. psammophila.





Postfire recovery characteristics of soil bacterial community at a clearcutting site of Pinus massoniana plantation.

MAN Jiarui, WANG Kuan, JIAO Zixuan, JIAO Pengyu, YAN Qiang, LIU Xian, HU Yalin, WANG Yuzhe

2025, 44(4):  1125-1134.  doi:10.13292/j.1000-4890.202504.023

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To investigate the recovery pattern of soil bacterial community after low intensity fires and its response to fire-deposited charcoal in subtropical forest, we conducted a field experiment with different amounts of charcoal input (charcoal removal (C0), single rate (C1), and double rates of charcoal input (C2) via adding the removed charcoal from C0 plots), and an unburnt area was selected as control (UB), at a harvest site of Pinus massoniana plantation subjected to prescribed burning. Soil samples at the 0-10 cm depth were collected one year and five years after the burning. Soil bacterial community diversity and structure was analyzed using the highthroughput sequencing technology. Soil physicochemical properties were measured to evaluate the potential mechanisms driving the dynamics of soil bacterial community. The results showed that the diversity of soil bacterial community was not affected by either fire or charcoal input (P>0.05). The number of amplicon sequence variants (ASVs) and Chao1 index were significantly lower while Shannon index was significantly higher in soils collected five years after fire than that collected one year after fire (P<0.05). Non-metric multidimensional scaling (NMDS) analysis based on Bray-Curtis distance showed that the structure of bacterial community in C0 and UB soil was significantly different one year after fire (P<0.05), while no difference was observed among the treatments five years after fire (P>0.05). Soil pH was the key factor regulating the changes of soil bacterial community structure, which accounted for 46.3% and 50.5% of the variations in soil bacterial community one and five years after fire, respectively. Acidobacteria, Proteobacteria, Actinobacteria, and Chloroflexi were the most abundant bacterial phyla. The relative abundance of Proteobacteria and Actinobacteria was significantly lower in soils collected five years after fire than that one year after fire, while the opposite trend was found for Firmicutes in C0 and C1 soils (P<0.05). The relative abundance of Gemmatimonadetes was significantly higher in C1 than UB soil. Higher abundance of Firmicutes was observed in C0 and C1 soils than UB soil five years after fire (P<0.05). Collectively, the diversity and structure of soil bacterial community after the low intensity fire can recover to the original level in the short term in subtropical forests. Fire-deposited charcoal exhibits long-term effects on the abundance of specific soil bacterial taxa. Future studies should focus on the temporal dynamics of soil bacterial taxa which regulate soil functions such as carbon and nutrient cycling after fire in subtropical forests.



Responses of phosphorus fractions in rhizosphere soil of Moso bamboo to nitrogen and biochar additions.

WANG Xiao, WANG Yixiong, JI Hangxiang, SHI Man, WANG Huilai, SONG Xinzhang, LI Quan

2025, 44(4):  1135-1143.  doi:10.13292/j.1000-4890.202504.009

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Moso bamboo (Phyllostachys edulis) forests, an important forest resource in subtropical China, are facing phosphorus (P) limitation and nitrogen (N)-P imbalance caused by N deposition. Although biochar has the potential to improve soil quality, its role in addressing N-induced P limitation is still unclear. We investigated the main and interactive effects of N (0, 30, and 90 kg N·hm^-2·a^-1) and biochar (0, 20, and 40 t·hm^-2) addition on P fractions (CaCl₂-P, Citrate-P, Enzyme-P, and HCl-P) in the rhizosphere soil of Moso bamboo forests. The results showed that the addition of N or biochar alone significantly increased Citrate-P, available phosphorus, contents and microbial biomass phosphorus  in rhizosphere soil, but significantly decreased soil pH (P<0.05). Under the conditions of N addition, biochar addition significantly increased rhizosphere soil CaCl₂-P, Citrate-P, and Enzyme-P contents (P<0.05). Under the conditions of biochar addition, N addition significantly increased rhizosphere soil CaCl₂-P, Citrate-P contents, and their proportions, but significantly decreased soil pH (P<0.05). There was a significant negative correlation between soil pH and CaCl₂-P or Citrate-P content in the rhizosphere soil (P<0.05). The activity of acid phosphatase was a key driver affecting the content of Enzyme-P. In summary, biochar addition can alleviate N-induced P limitation by increasing soil P availability. These findings provide a scientific reference for the sustainable management of Moso bamboo forests under the context of global change.





Effects of straw return methods on organic carbon fractions in soil aggregates of saline-alkaline dryland.

SUN Yunyun, DOU Jingang, LIU Fangming, GAO Yushan, HOU Zhonghua, FAN Wei, LIU Huitao

2025, 44(4):  1144-1151.  doi:10.13292/j.1000-4890.202504.005

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With the vigorous promotion of straw returning technology, different straw returning methods have been widely applied in Northeast China. We examined the effects of straw returning on organic carbon in a saline-alkaline tillage soil, aiming to provide a scientific basis for the rational utilization of straw. We set up a field experiment with four treatments, including no straw application (CK), no-tillage + straw coverage (NTS), rotary tillage + straw (RTS), and deep tilling + straw (PTS). The results showed that straw returning significantly increased the contents of particulate organic matter (Fm-POM) in free microaggregates, particulate organic matter (mM-POM) in occluded microaggregates and organic carbon content of silt + clay (mM-SC) components in closed microaggregates in 0-20 cm soil layer. In 0-20 cm soil layer, RTS treatment had higher contents of coarse particulate organic matter (MA(c)POM), closed microaggregates (mM), mM-POM and mM-SC components, which improved the stability of organic carbon in topsoil. In the 20-40 cm soil layer, PTS treatment increased organic carbon contents in mM-POM and mM-SC fractions. Straw returning can be used as an effective measure to improve organic matter in saline-alkali soil.





Spatiotemporal characteristics of soil seed bank in abandoned farmlands in tropical areas.

DONG Qianzhen, HU An, XIA Murong, DUAN Qianwen, ZHANG Rui, LI Xinyong

2025, 44(4):  1152-1160.  doi:10.13292/j.1000-4890.202504.025

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To explore the spatiotemporal pattern of soil seed bank and its influencing factors after farmland abandonment in the tropics, we used seed germination experiments to examine the composition and distribution of soil seed banks in different soil layers (0-5, 5-10, 10-20 cm) in different abandonment years (2nd, 5th, and 10th year of abandonment) in the western and eastern regions of Hainan Island. The results showed that the maximum soil seed bank density of abandoned land in the western and eastern regions of Hainan Island in the second year after farmland abandonment was 49906 and 55417 seeds·m^-2 respectively. There was no significant difference between the two regions (P> 0.05). After five years of abandonment, soil seed bank density in the eastern region was significantly higher than that in the western region. After 10 years of abandonment, soil seed bank density in the western region was significantly higher than that in the eastern region. As the years of abandonment increase, soil seed bank density in the western part of Hainan Island decreased first and then increased, and soil seed bank density in the eastern part of Hainan Island showed a gradual decreasing trend. The richness and diversity of soil seed banks in both regions increased over years. Aboveground vegetation and soil seed banks showed non-consistency during succession, resulting in a low similarity between the two, ranging from 3% to 21%, with a downward trend over time. Years of abandonment and its interaction with region had significant effects on soil seed bank density and diversity (P<0.05). The results provide an important reference for understanding the spatiotemporal pattern of soil seed bank and its influencing factors after farmland abandonment in tropical areas, with theoretical and practical significance for guiding farmland restoration and utilization and ecological environment protection.





Estimation of soil soluble salt-based Cl^- content in northern Ningxia, China  based on multi-source spectral remote sensing.

SHANG Tianhao, CHEN Ruihua, JIA Pingping, ZHANG Junhua

2025, 44(4):  1161-1169.  doi:10.13292/j.1000-4890.202504.012

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Series of water-soluble anions in soils can be used to identify the types and degrees of soil salinization. This study aimed to determine the optimal model for estimating soil soluble anion content by multispectral remote sensing. Based on Sentinel-2B and Landsat8-OLI multispectral data and the contents of anions in saline soil in Pingluo County, northern Ningxia of northwest China, the sensitive spectral data were screened by Pearson correlation coefficient (PCC) and gray relational analysis (GRA). A soil anion content estimation model based on support vector machine (SVM) was constructed. The feasibility of remote sensing images to estimate soil anions in arid and semi-arid regions was determined by comparison with partial least squares regression (PLSR). The results showed that: (1) Cl^- was the highest soil anion, followed by SO₄^2-. The Cl^- content showed strong variation. (2) With PCC and GRA as variable screening methods, no sensitive variables of SO₄^2- and HCO₃^- were selected. Cl^- satisfied the conditions and there were multiple sensitive spectral indicators. (3) Overall estimation efficacy of Cl^- model constructed by PCC based variable screening approach was better than GRA. (4) For the two inversion models of Cl^- content, the SVM model showed a higher accuracy than PLSR model. For the single-phase images, the best inversion performance for Cl^- estimation was achieved with the PCC-SVM model constructed by the sensitive band and salinity index selected by Sentinel-2B, with the values of coefficient of determination (R_P²) and relative percent deviation (RPD) being 0.989 and 6.616. For the Sentinel-2B and Landsat8-OLI combined images, PCC-SVM model constructed with the sensitive bands achieved the best inversion effect, with the values of R_P² and RPD being 0.895 and 2.066. Our results indicated the feasibility of quantitative estimation of Cl^- based on Sentinel-2B satellite data, providing a scientific basis for the rapid identification of soil salinization in local and similar areas.








Effects of degradable and non-degradable microplastics on soil organic carbon mineralization in a coastal wetland soil.

CHEN Kun, XI Min, CHEN Feitong, LIU Shuming, KONG Fanlong, JIANG Zhixiang

2025, 44(4):  1170-1180. 

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Microplastics (MPs), as a kind of emerging pollutant, have been widely found in soils. However, the effect of MPs on the mineralization of soil organic carbon (SOC), especially the difference between degradable and non-degradable MPs, is still unclear. The relevant mechanisms need to be further revealed. In this study, a soil incubation experiment (100-day) was conducted with adding degradable polylactic acid (PLA) and non-degradable polyethylene (PE) MPs to a coastal wetland soil, respectively. The results showed that, regardless MPs type, MPs addition significantly reduced the cumulative CO₂ emissions. Compared with the PLA-MPs, the PE-MPs had stronger inhibitory effect on the cumulative CO₂ emissions. Furthermore, the addition of both MPs types significantly increased SOC content and improved the stability of soil aggregates, while remarkably reduced the contents of dissolved organic carbon, NH₄⁺-N, and NO₃^--N. In terms of microbial property, the addition of MPs decreased the diversity of soil microbial community and the activity of carbon mineralization associated bacteria and enzymes. The reduction of available substrates for SOC mineralization, the enhancement of physical protection of soil aggregates, and the reduction of SOC mineralization-related bacterium and enzyme activities were identified as the main mechanisms for the lower SOC mineralization in MPs added soils. Overall, non-degradable PE-MPs had stronger effect on soil physical, chemical, and microbial indices than degradable PLA-MPs. Our results can provide important data support and theoretical basis for in-depth understanding of the environmental effects of MPs in coastal wetland soils.





Stress response and enrichment characteristics of three herbaceous species to Pb, Zn and Cd compound heavy metals.

SUN Minhan, FAN Shuanxi, ZHANG Nan

2025, 44(4):  1181-1190.  doi:10.13292/j.1000-4890.202504.034

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To screen plants that can tolerate and accumulate high levels of Pb, Zn and Cd compound heavy metals, a pot experiment was conducted with seven combination concentrations of Pb, Zn and Cd. The response of antioxidant enzymes (SOD, CAT, POD) and other physiological indicators (MDA and Pro) in leaves of Symphytum officinale, Ricinus communis, and Lolium perenne under the stress of Pb, Zn and Cd compound pollution were examined. The enrichment characteristics （enrichment amount, bioaccumulation factor (BCF), and translocation factor (TF)） for Pb, Zn and Cd in different parts of three species were observed. The results showed that SOD of S. officinale and R. communis increased with intensified composite stress of Pb, Zn, and Cd. The SOD of L. perenne increased first and then decreased. The CAT of S. officinale and L. perenne showed the “hormesis effect”. The CAT of R. communis decreased gradually. The POD of S. officinale and L. Perenne decreased first and then increased. The POD of R. communis increased first, then decreased and then increased. The MDA of S. officinale showed a decreasing trend. The MDA of R. communis showed an increasing trend. The MDA of L. perenne was small. The Pro of R. communis and L. perenne showed a pattern of first rising and then falling, while that S. officinale showed a gradually decreasing trend. In general, the SOD, CAT, POD, MDA, and Pro of the three species differed across the concentration gradient (P<0.05). Based on the enrichment characteristics of Pb, Zn and Cd in the three species, the enrichment amount, BCF and TF of S. officinale for Pb, Zn, and Cd simultaneously achieve the limit requirements of each index of hyperaccumulator. S. officinale is a potential hyperaccumulating species for Pb, Zn and Cd complex heavy metals and can be used as a preferred plant for remediation of Pb, Zn and Cd contaminated soil.





Characteristics of phytoplankton community structure and its environmental influencing factors in Taihu Lake during the early stage of fishing ban.#br#

SHENG Piao, YANG Min, CHEN Wenkai, LIU Xiangjiang, XIN Wei, CHEN Yushun

2025, 44(4):  1191-1201.  doi:10.13292/j.1000-4890.202504.033

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To clarify the spatial and temporal variations of phytoplankton community structure of Taihu Lake during the early stage of the fishing ban and their key environmental driving factors, we investigated water environmental factors and phytoplankton community structure at 18 sampling sites in Taihu Lake in May (spring), August (summer), November (autumn) and December (winter) of 2020. A total of 130 phytoplankton species from 7 phyla and 67 genera were identified. Chlorophyta (65 species) was the dominant group, followed by Bacillariophyta (30 species) and Cyanophyta (20 species). The dominant species throughout the year included Microcystis sp., Dolichospermum sp., and Pseudanabaena sp. Dominant species differed across seasons and regions, but the dominance of Microcystis sp. was the greatest. There was significant seasonal variation in phytoplankton density and biomass, and no spatial difference. The mean density and biomass were the highest in summer, with (1.14±1.04)×10⁸ cells·L^-1 and 14.67±9.64 mg·L^-1, respectively. Phytoplankton density was the lowest in autumn, with (0.32±0.55)×10⁸ cells·L^-1, while the lowest biomass of 2.49±4.35 mg·L^-1 in winter. Redundancy analysis showed that nine water quality indicators, including water temperature, total nitrogen, turbidity, chemical oxygen demand, nitrite, water depth, pH, conductivity and dissolved oxygen, significantly influenced the structure of phytoplankton community. Based on the evaluation results of dominant species, diversity index and comprehensive trophic state index, the water quality of Taihu Lake was between moderately and heavily polluted throughout the year. The study can provide scientific information for understanding the current status of phytoplankton community structure and the evaluation of ecosystem health of the Taihu Lake. It also provides basic data support for the impact of the implementation of fishing ban on lake ecosystem.





Screening of the effective components of the plant growth regulators promoting tillering in ornamental bromeliads and the underlying mechanism.

WANG Qiang, MA Xiaoyun, LI Yu, FENG Mengnan, CAO Dongmei

2025, 44(4):  1202-1211.  doi:10.13292/j.1000-4890.202504.045

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To screen the effective reagents for promoting the tillering of Ornamental bromeliads, different concentrations of ethephon, paclobutrazol, and 6-BA were used, with water as the control. The tillering-promoting effects were evaluated, and the underlying mechanism was explored. The results showed that 100 ppm ethephon was the most suitable reagent for promoting the tillering of ornamental bromeliads ‘flat-headed red’. Under the concentration of 100 ppm ethephon, the tillering coefficient could reach 10 or above when the fertilization was stopped 30 days before the treatment, and pH of ethephon solution was adjusted to 6 with potassium carbonate. Compared with the control, ethephon treatment increased leaf number and plant height, while had limited effects on leaf length, leaf width, and crown width. Moreover, ethephon treatment promoted C/N ratio in roots, stems and leaves, the chlorophyll content in the later stage, as well as the accumulation of total nitrogen, phosphorus and potassium in plants. The contents of total nitrogen, phosphorus and potassium were positively related to tiller number. These results suggested that the ethephon treatment might promote tillering through increasing C/N ratio and the contents of total nitrogen, phosphorus and potassium in ornamental bromeliads. This work provided technical support for the breeding of ornamental bromeliad seedlings and the possibility of localizing ornamental bromeliad seedlings.





Effects of phosphorus and potassium operations on the quality and RVA characteristic values of northern Japonica rice.

LIU Ya, GAO Jiping, SONG Qi, MA Qinchun, MA Cheng, LIU Huiling, ZHONG Min, ZHANG Wenzhong

2025, 44(4):  1212-1219.  doi:10.13292/j.1000-4890.202504.007

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To investigate the effects of phosphorus and potassium management on the quality of northern Japonica rice, we conducted a field experiment with different phosphorus and potassium treatments in Shenyang from 2021 to 2022. Cultivars ‘Shennong 265’ and ‘Liaojing 294’ were used as the test materials. There were two phosphorus application levels: 89.25 kg·hm^-2 (P1) and 120.75 kg·hm^-2 (P2), with a potassium fertilizer operation ratio of 7∶3 (K1) and 8∶2 (K2) for base-tiller fertilizer and panicle fertilizer (with a total amount of 105 kg·hm^-2), respectively. No phosphate and potassium fertilizer application (P0K0) was set as control, resulting in a total of five treatments. We measured nutritional quality, cooking and taste quality, appearance, processing quality, and characteristic rapid visco analyzer (RVA) profile values of the rice at maturity. The application of phosphorus and potassium increased gluten content, total starch content, amylopectin content, brown rice rate, milled rice rate, head rice rate, appearance value, balance degree, taste value, viscosity, setback, peak viscosity, hot viscosity, and final viscosity of both cultivars, but reduced the amylose content, chalk grain rate, chalkiness, disintegration value, and consistence value of both cultivars. Compared with the other treatments, P2K2 treatment increased the appearance, balance degree, taste value, and viscosity of both cultivars, and reduced chalk grain rate and chalkiness. In 2021 and 2022, the taste value of ‘Liaojing 294’ treated with P2K2 significantly increased by 1.18%-20.08%, compared with the other treatments. Peak viscosity of both cultivars was significantly negatively correlated with chalk grain rate and amylose content and significantly positively correlated with appearance, balance degree, viscosity, and taste values. P2K2 treatment can fully leverage the synergistic effects of phosphorus and potassium, synchronously improving rice quality and optimizing certain characteristic RVA profile values of the rice.





Effects of humic acid and D-arginine on root growth of foxtail millet (Setaria italica) seedlings under drought stress.

SHEN Jie, SONG Xiaojing, ZHONG Dandan, QIN Cheng, PEI Penggang, WANG Xi, LEI Haiying, HAO Xingyu

2025, 44(4):  1220-1225.  doi:10.13292/j.1000-4890.202504.011

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We examined the effects of humic acid (HA) and D-arginine (D-Arg) on root growth of foxtail millet seedlings of cultivars Jingu 21 and Zhangza 10 under drought stress. There were four treatments, including control (CK), drought stress (Dr), humic acid sprayed on the leaves under drought stress (Dr + HA), and humic acid and D-arginine sprayed on the leaves under drought stress (Dr + HA + D-Arg). We measured root growth, endogenous arginine (Arg) content, and arginine decarboxylase (ADC) activity of millet seedlings. The results showed that humic acid significantly increased the total root length, total root surface area, average root diameter, total root volume and root biomass under drought stress. Root dry biomass of Jingu 21 and Zhangza 10 was 40.41% and 55.57% higher than that of the Dr treatment, respectively (P<0.05). Under the treatment of Dr + HA, root activity, ADC activity, and endogenous Arg content were 18.58%, 22.43%, 31.71% (for Jingu 21), and 54.77%, 18.71%, 37.89% (for Zhangza 10) higher than those of the Dr treatment, respectively (P<0.05). Humic acid significantly improved root activity, promoted the synthesis of endogenous Arg, and enhanced ADC activity, thereby promoting root growth and alleviating the damage caused by drought stress on root systems. The effect of D-Arg was opposite to that of humic acid, suggesting that humic acid could improve the drought resistance of millet by promoting the synthesis of polyamines. There were significant positive correlations among root morphological indices and between ADC activity and endogenous Arg content under humic acid treatment (P<0.01). This study provides a new way to analyze the action mechanism of humic acid, which plays an important role in the application of humic acid in millet production and the development of green agriculture.





Cadmium and zinc uptake by lettuce (Lactuca sativa L.) from soil contaminated by two kinds of zinc minerals.

PAN Xia, CAO Xinyan, LIU Juan, LI Xinyang, WU Longhua, NI Caiying

2025, 44(4):  1226-1235.  doi:10.13292/j.1000-4890.202504.037

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The exploitation of zinc mines has led to a continuous influx of metals into soils through mining and smelting, resulting in the risks of excessive metal concentration in crops. Compared with that in non-mining areas, metals in soils around mines mainly exist in particulate form, releasing metal ions and metal-bearing nanoparticles with different bioavailability. With a pot experiment, we investigated the effects of Zn-mineral-derived cadmium (Cd) and Zn from typical zinc (Zn)-sulphide mineral (sphalerite, SP) and -oxy-salt mineral (smithsonite, SM) on the growth of lettuce (Lactuca sativa L.), the available content of Cd and Zn in soil, and Cd and Zn uptake by lettuce. The results showed that: (1) The addition of 0.1% and 1.0% SM significantly inhibited lettuce growth (P<0.05), with a reduction of 81.2% in fresh weight under the latter addition, whereas SP addition had no significant effect on lettuce growth (P>0.05). (2) CaCl₂ and EDTA-extractable Cd and Zn in the soil significantly increased with SM addition but showed no response to SP addition. SM-spiked soils had significantly higher CaCl₂ and EDTA-extractable Cd and Zn concentrations and higher Zn/Cd molar fractions than those in SP-spike soils. (3) The total amount of Cd and Zn in the lettuce shoot increased and decreased with a higher addition amount of Zn mineral in SP and SM-treatment, respectively. The total amount of Cd and Zn in the lettuce shoot of the SM treatment was significantly higher than that of the SP treatment. (4) The results of transmission electron microscopy combined with energy-dispersive X-ray spectroscopy (TEM-EDS) showed that Cd- and Zn-bearing nanoparticles occurred in lettuce shoots under both Zn mineral-spiked treatments. The mechanism underlying the formation of these nanoparticles needs to be considered in further work. This study provides a new perspective for assessing the risk of heavy metal uptake in soil and crops from different lead-zinc mining areas.





Effects of lotus-turtle-turtle-fish co-cultivation model on pests and diseases in lotus field.

ZHANG Qin, CHEN Can, HUANG Huang, LONG Ziwang

2025, 44(4):  1236-1244.  doi:10.13292/j.1000-4890.202504.010

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A field experiment was conducted to examine the effects of different cultivation modes on diseases and insect pests in lotus field. There were four treatments, including lotus-turtle-turtle-fish co-cultivation (JGBY), lotus-turtle-fish cocultivation (JGY), seed lotus monoculture (JCK), and seed lotus ecological planting (JCK0). The results showed that compared with JCK0, the control efficacy of JGBY, JGY, and JCK on lotus brown rot was 21.3%, 20.8% and 42.5%, respectively, at the time with the greatest difference of the incidence among all treatment modes. The control efficacy of JGBY, JGY, and JCK on leaf blight was 17.7%, 16.4% and 37.6%, respectively, and that on lotus root rot diseases was 7.7%, 6.4% and 27.5%, respectively. The control efficacy of JGBY on main diseases was better than that of JGY, but was not as good as that of JCK. At the peak occurrence of each pest, the control efficacy of treatments on Donacia provosti and Pomacea canaliculata was the best. Compared with JCK0, population density of Donacia provostii under JGBY, JGY, and JCK decreased by 76.9%, 46.2%, and 84.6% respectively, while population density of golden apple snail decreased by 69.2%, 53.8% and 46.2% respectively. The control efficacy of treatments on Donacia provosti and Pomacea canaliculata were as follows: JGY < JGBY < JCK, and JCK < JGY < JGBY. JGBY and JGY can play a stable and continuous role in the prevention and control of the damage of Donacia provostii and Pomacea canaliculata. However, the control efficacy on Rhopalosiphum nymphaeae and Spodoptera litura was not as good as that of JCK treatment, which should be combined with chemical control. Compared with JCK, JGBY and JGY treatment modes can reduce the amount of pesticides and fertilizers, reduce environmental pollution, and improve ecological and economic benefits.





Effects of tillage methods on soil aggregate nematode community in fluvo-aquic soil area of North China.

HU Runan, SHEN Xiaolin, WANG Su, FAN Ping, TAN Bingchang, ZHANG Guilong, WANG Lili

2025, 44(4):  1245-1252.  doi:10.13292/j.1000-4890.202504.035

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Nematodes are a class of active organisms in soils, with important ecological functions in maintaining the stability of soil ecosystems and promoting material cycling and energy flow. At present, the response of nematode communities in soil aggregates in fluvo-aquic soils of the North China Plain under different tillage methods is not clear. In this study, we investigated the effects of tillage methods on nematode community in soil aggregates in a fluvo-aquic soil in Qihe County, Shandong Province. There were four treatments, including rotary tillage + straw return (RT), deep plowing + straw return (DP), deep loosening + straw return (SS) and no-tillage + straw return (NT). The results showed that deep loosening and no-tillage treatments increased the percentage of bacterial-feeding nematodes in small mega-aggregates (2-5 mm), and decreased that of plant-parasitic nematodes. Moreover, deep loosening and no-tillage treatments increased the Wasilewska index (WI), which was favorable for bacterial-feeding nematodes to participate in organic matter and nutrient cycling. Deep loosening and no-tillage treatments increased the soil nematode pathway index (NCR), and increased soil organic matter index in large mega-aggregates (> 5 mm), within which the decomposition pathway of soil organic matter was dominated by bacteria. Soil organic carbon, total nitrogen content, and soil pH were the main environmental factors affecting the total number of soil nematodes and the number of each trophic group. Overall, deep loosening and no-tillage conditions favored the formation of stable nematode community structure in soil aggregates, which provides a theoretical basis for the selection of farming practices in the fluvo-aquic  soils of the North China Plain.





Effects of precipitation regime change on the resistance of soil nematodes to nitrogen deposition.

YANG Changrao, MO Xiaomei, ZHENG Guo, WU Pengfeng, LI Yingbin, CUI Shuyan

2025, 44(4):  1253-1260.  doi:10.13292/j.1000-4890.202504.028

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Soil nematodes are an important part of underground community and play a crucial role in ecosystem energy flow and material cycling. Elevated nitrogen (N) deposition and precipitation regime alteration are two major forms of global change, which affect soil nematodes. Nitrogen deposition has adverse effects on soil nematodes, while precipitation alteration might affect the responses of nematodes to N deposition. To investigate how precipitation regime alteration affects the resistance of soil nematode community to N deposition can help understand the response of soil nematodes to climate change. In this study, we conducted an 8-year manipulative field experiment comprising precipitation addition (totaling 80 mm, with varied precipitation frequency and intensity) and N addition in a temperate steppe of Inner Mongolia. There were five precipitation intensities (2, 5, 10, 20 and 40 mm), and two N addition levels (N10: 10 g N·m^-2·a^-1; N0: control). The response of soil nematode resistance to N deposition under different precipitation addition intensities was quantified by the resistance of soil nematode abundance and diversity. The results showed that the resistance of bacterivore nematode abundance to N deposition was the highest under 40 mm precipitation addition intensity among all precipitation addition intensities. The resistance of fungivore abundance to N deposition was higher under low precipitation intensity. The resistance of predator-omnivore nematode abundance to N deposition was higher under high precipitation intensity than under the moderate precipitation intensity. The resistance of plant parasitic nematode abundance to N deposition reached its peak under low precipitation intensity. Moreover, the resistance of evenness, trophic diversity, and Shannon diversity to N deposition was significantly higher under low precipitation intensity than other treatments. Changes in soil moisture and pH induced by precipitation regime alterations are the main factors affecting soil nematode community.





The herbicide-induced water pollution affects the adaptability of animals to wetland water environment by destroying the waterproof layer of body surface: A case study of Apodemus agrarius. 

ZUO Fangming, ZHANG Chen, ZHANG Meiwen, TAO Shuanglun, ZHOU Xunjun, HUANG huanan

2025, 44(4):  1261-1269.  doi:10.13292/j.1000-4890.202504.043

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To explore whether herbicide induced water pollution can affect the adaption of animal by damaging the waterproof layer of their bodies, we examined the effects of three widely used herbicides (glufosinate, glyphosate and bispyribac-sodium) in China on the waterproof performance and swimming ability of Apodemus agrarius. The results showed that: (1) The waterproof of the fur of Apodemus agrarius swimming in the three herbicide aqueous solutions (at application concentrations in farmland) was significantly lower than that in the control, with no gender difference in this performance. (2) Higher concentration of herbicide led to greater damage to waterproof properties of mouse fur. (3) When the concentrations of glufosinate, glyphosate and bispyribac-sodium reduced to 0.033‰, 0.068‰ and 0.00165‰ respectively, they no longer damage the waterproof properties of mouse fur. Our results indicate that herbicide-induced water pollution can damage waterproof properties of small mammals such as Apodemus agrarius, thereby affecting their aquatic adaptations and potentially causing negative impacts on their survival in water environments such as wetlands.





Effects of short-term high and low temperature on the survival rate of Trichopria drosophilae. 

CHEN Qiang, TIAN Ye, LI Juan, ZHANG Jinlong, REN Hui, CHEN Guohua, ZHANG Xiaoming

2025, 44(4):  1270-1275.  doi:10.13292/j.1000-4890.202504.008

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Trichopria drosophilae is one of the dominant parasitic natural enemies of Drosophila suzukii, with great biocontrol potential against D. suzukii. Under the background of global warming and frequent extreme climate events, it is important to clarify the effect of short-term high and low temperature stress on the survival of T. drosophilae. We examined the effects of short-term high and low temperature on the survival rate of T. drosophilae under laboratory conditions. Logistic model was used to fit the mortality rate of T. drosophilae with temperature changes. The temperature adaptation zones of T. drosophilae to temperature were divided based on the results of the model. The results showed that the survival rate of T. drosophilae decreased with increasing temperature (high temperature) or decreasing temperature (low temperature). The mortality of adult female and male T. drosophilae peaked at 35 ℃ and -8 ℃. The temperature zone of T. drosophilae was divided into: lethal low temperature zone below -7.51 ℃, sublethal low temperature zone between -7.51 ℃ and 7.06 ℃, suitable temperature zone between 7.06 ℃ and 29.82 ℃, sublethal high temperature zone between 29.82 ℃ and 35.01 ℃, and lethal high temperature zone above 35.01 ℃. Short-term high and low temperature reduced the survival rate of T. drosophilae. Our results can provide a theoretical basis for the artificial propagation and efficient biocontrol utilization of T. drosophilae.





Effects of upstream training on immunity and antioxidant capacity of Takifugu obscurus.

GU Lingling, LI Xia, FENG Guangpeng, HAN Zhiqiang

2025, 44(4):  1276-1283.  doi:10.13292/j.1000-4890.202504.002

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Conducting exercise training of habitat adaptability before the enhancement and releasing of aquatic organisms is one of the key links to improve the survival rate of larval and juvenile fishes in the wild. To investigate the suitable exercise strengthening techniques before releasing, we examined survival rate (SR), condition factor (CF), hepatosomatic index (HSI) and cardiac index (CI) of Takifugu obscurus under different training intensities (0, 0.75, 1.5 BL·s^-1) and training time (7, 14, and 28 days) in the upstream training experiments. The changes of lysozyme (LZM), cortisol (COR), superoxide dismutase (SOD), lactate dehydrogenase lysozyme (LDH), and glycogen (Gn) levels in the serum of T. obscurus were measured. The results showed that the SR in the 0.75 BL·s^-1 training group was higher than that of the control group and the 1.5 BL·s^-1 training group after 28 days. The contents of LZM, COR, SOD, LDH, and Gn in all training groups were significantly higher than that in control group (P<0.05), without significant variations among the training groups (P>0.05). Moreover, the contents of LZM and COR first increased and then decreased with the extension of training time. The content of LDH also increased with the extension of training time. In summary, the appropriate upstream training (training intensity of 0.75 BL·s^-1 with 14 days) can effectively improve the immune enzyme activity of T. obscurus, and enhance the survival rate and efficiency of releasing.





Simulation of NPP dynamics and climate response of typical subtropical forest types based on Biome-BGC modeling.

HUANG Yun, HU Fangqing, ZHENG Bofu, SONG Xu, XU Liliang, ZHU Jinqi, WAN Wei

2025, 44(4):  1284-1296.  doi:10.13292/j.1000-4890.202504.019

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Net primary productivity (NPP) is an important index to evaluate the carbon budget of forest ecosystems. It is of great significance to accurately assess the changes of forest NPP to cope with climate change. Based on the Biome-BGC model with localized parameters, we simulated the dynamics of NPP in six typical subtropical forests in Xiuhe River Basin of Jiangxi Province during 1960-2021, and analyzed the responses of forest NPP to temperature and precipitation under different climate scenarios. The results showed that: (1) From 1960 to 2021, the NPP of different forest types was in order of bamboo forest (655.20 g C·m^-2·a^-1) > evergreen coniferous forest (629.42 g C·m^-2·a^-1) > evergreen broad-leaved forest (600.01 g C·m^-2·a^-1) > evergreen coniferous and broad-leaved mixed forest (596.98 g C·m^-2·a^-1) > deciduous broad-leaved forest (325.20 g C·m^-2·a^-1) > shrub (266.43 g C·m^-2·a^-1). (2) As for the inter-monthly variation of NPP, deciduous broad-leaved forest showed a unimodal trend and reached the highest value in August, while other forests decreased to a bimodal trend in August. Except for deciduous broad-leaved forest and shrub forest, the NPP of forests showed a significant negative correlation with temperature from July to September, but a positive correlation with precipitation, indicating that increased temperature and decreased precipitation in summer greatly affected vegetation growth. (3) According to the fitting strength of meteorological factors, the response strength of NPP to temperature was greater than that of precipitation, and the fitting strength of temperature to NPP of bamboo forest and deciduous broad-leaved forest was stronger (R²>0.46; P<0.01). The correlation between precipitation and NPP in evergreen coniferous forest, bamboo forest, shrub forest and broad-leaved deciduous forest was relatively weak (R²<0.21; P<0.01). (4) In the future climate scenario, appropriate temperature increase is helpful to promote vegetation growth, but NPP will be inhibited when temperature increase exceeds the threshold. In the precipitation scenario, NPP is positively correlated with precipitation. The response range of NPP to temperature is much greater than that of precipitation, and the effect of the combination of temperature and precipitation is stronger than that of the single change scenario.








Estimation of biodiversity in small watershed based on Sentinel-2A fused multi-vegetation index.

CHENG Jiaqi, ZHANG Jianjun, ZHANG Yanni, ZHANG Xiaojie, ZHANG Xuexia

2025, 44(4):  1297-1305.  doi:10.13292/j.1000-4890.202504.020

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Timely and rapid monitoring of biodiversity is of great significance for forest management and diversity conservation. The traditional method of plot survey cannot meet the data needs of biodiversity monitoring and evaluation at landscape and regional scales. In this study, 27 Sentinel-2A image data in 2022 were used to construct a biodiversity estimation model at the small watershed scale using 12 vegetation indices. The spatial distribution pattern of biodiversity Caijiachuan Basin, Jixian County, Shanxi Province was explored with this model. The results showed that stand density of Robinia pseudoacacia was not the only factor controlling biodiversity in the forest. Simpson diversity index (D), Shannon diversity index (H) and Pielou evenness index (J) were significantly correlated with the percentage of infrared percentage vegetation index (IPVI) and red-edge chlorophyll index (CIre) (P<0.01). The mean square errors (MSE) of the estimated and measured values of D, H and J in the remote sensing model of biodiversity were 0.021, 0.192 and 0.016, respectively, indicating that the estimation model constructed by the vegetation indices can be used for biodiversity estimation and monitoring in the study area. The biodiversity level was best estimated on the shady slope areas with high altitude.





Estimation of winter wheat leaf area index (LAI) and validation of LAI remote sensing products based on UAV hyperspectral imagery.

LI Junling, LI Mengxia, XIONG Kun, TIAN Hongwei, ZHANG Yuchen, YU Weidong

2025, 44(4):  1306-1313.  doi:10.13292/j.1000-4890.202504.003

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The variations of leaf area index (LAI) can be used to monitor growth status and estimate yields of winter wheat. However, there are several limitations in available studies, including scale mismatch between ground observation data and satellite data leading to scale effect and the weak sensitivity of commonly used multispectral data relative to hyperspectral data. To effectively use the hyperspectral information and select the best bands, LAI estimation models were proposed with the aim of improving LAI estimation accuracy. In this study, we used unmanned aerial vehicle (UAV) hyperspectral data, serving as a bridge between ground observations and satellite data. We acquired ground-measured LAI data, UAV hyperspectral data, and GF-1 data during the greening period of winter wheat. Different forms of transformation and calculation of characteristic variables were conducted on the hyperspectral data, followed by establishing the area of interest. UAV image pixels with the same scale as ground observation were calculated. We further conducted correlation analyses between LAI and various spectral transformation forms as well as vegetation indices at the same scale. LAI sensitive bands or indices were filtered. LAI inversion at different scales based on UAVs and GF-1 satellites was developed. The results showed that the sensitive bands or indices of winter wheat LAI were 635, 655, 693, 704, 714, 721, 724, 763, 806, 813, 900, 936 nm first derivative, 714, 717, 763, 767, 784, 806, 813, 900, 903, 936 nm  second derivative, as well as the sensitive spectral indices SD_y, DVI, MSAVI2, NLI, and SAVI. An inversion model for estimating LAI from UAV hyperspectral images was developed utilizing various techniques, such as stepwise regression, partial least squares, and ridge regression. According to accuracy comparisons, ridge regression model was considered the optimal. Based on the upscaling method, a GF-1 winter wheat LAI estimation model was constructed. The simulation results were used as relative true values to validate the LAI remote sensing inversion products. The correlation coefficient between FY3_1KM_LAI products and GF_1KM_LAI products reached 0.787, indicating a strong correlation between FY3_LAI products and relative truth. This suggests that the results could be applied in daily operational services and research. In this study, we addressed the accuracy of inversion models under different data sources by upscaling, and discussed the ability of different remote sensing information sources in estimating LAI of winter wheat. Our results provided scientific guidance for crop management and theoretical basis for precision agriculture research.





Assessing habitat suitability of Elaphodus cephalophus in Hunan Province based on MaxEnt model.

YANG Mengdie, DENG Zeshuai, CAO Yue, KANG Zujie, ZHANG Yuzhong, XIANG Jianjun, TANG Longping, YANG Daode

2025, 44(4):  1314-1320.  doi:10.13292/j.1000-4890.202504.021

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Habitat suitability assessment can identify the areas suitable for wildlife survival, revealing the relationship between wildlife and habitat, and thus could provide technical support for conserving rare and endangered wildlife. The tufted deer (Elaphodus cephalophus) is widely distributed in southern China and classified as a second-level key protected wildlife species in the country. To investigate the potential habitat suitability of tufted deer in Hunan Province, we analyzed 177 distribution points captured by infrared cameras. A MaxEnt model was constructed based on 23 environmental factors, including climate, topography, and vegetation type. The model was optimized using the EMNeval package in R software and then was used to analyze the distribution status of suitable habitats for tufted deer and the main environmental influencing factors. The results showed that the average AUC value of the training set was 0.967, indicating excellent performance in prediction. The main environmental factors influencing the habitat suitability of tufted deer in Hunan Province include altitude (Alt), monthly mean diurnal range (Bio02), vegetation type (Veg), precipitation seasonality (Bio15), isothermality (Bio03), and mean temperature of the driest quarter (Bio09), with a total contribution of 73.3%. The potential suitable habitats for tufted deer in Hunan Province are mainly distributed in the Wuling Mountains, Xuefeng Mountains, and Nanling Mountains, covering a total area of 61931.57 km² or 29.24% of the province’s land area. The highly suitable habitat area is 29914.46 km², and the moderately suitable habitat area is 32017.11 km². To enhance the conservation and management of tufted deer population throughout Hunan Province, it is therefore essential to strengthen monitoring efforts and to prioritize the ecological protection of habitats where small populations are located.



Spatiotemporal variation and climate responsiveness of NDVI in Liaohe River Basin.

YANG Mengqiu, ZHU Ling, WANG Rui, HU Zhenguo

2025, 44(4):  1321-1333.  doi:10.13292/j.1000-4890.202504.004

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Global climate change would affect regional vegetation changes. Clarifying the spatiotemporal variations of normalized difference vegetation index (NDVI) in a basin and its response to climate change can provide important insights into regional ecological environment construction and management. Based on the perspective of geographical micro-regional differentiation, we constructed geographical units with characteristics of Liaohe River Basin (Liaoning section). GIS and other software were used to analyze the MODIS-NDVI remote sensing data acquired from 2000 to 2022. The data of temperature and precipitation were collected during the same period. The methods of Theil-Sen + Mann-Kendall test, coefficient of variation and partial correlation analysis were employed to identify the spatiotemporal patterns and climate responsiveness of NDVI during the growing season in different geographical units. The average NDVI during the growing season in different geographical units showed an increasing trend, but with different growth rates and obvious spatial heterogeneity. The analysis of trend significance and variation coefficients showed that gentle slope luvisols on sunny/shady slopes had a positive interaction with vegetation, indicating that they are suitable for the growth of various vegetation types. Vegetation on gentle slope phaeozems had been restored to a good level, but there were still some areas with degradation. Plant community structure on steep slope luvisols on sunny/shady slopes was in a relatively stable state. NDVI in different geographical units had a weak correlation with temperature, and a significant positive correlation with precipitation. Our findings provide references for evaluating potential vegetation restoration as well as ecological restoration zoning and management in Liaohe River Basin (Liaoning section).



Evolution of O₃ spatial and temporal patterns in the east of the Hu Huanyong Line and its influencing factors.

SONG Wenfang, HU Beibei, LI Hongliu, YUAN Xuesong, XIAO Zishuang, HOU Xingshuai

2025, 44(4):  1334-1342.  doi:10.13292/j.1000-4890.202504.018

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We examined the spatial-temporal evolution of O₃ across 237 cities in the east of the Hu Huanyong Line. The socio-economic data, air pollutant (PM_2.5, SO₂, NO₂) and O₃ concentration data during the period of 2015-2020 were analyzed using the spatial autocorrelation method. The spillover effects of influencing factors were examined by employing the spatial Durbin model. The results showed that: (1) O₃ pollution demonstrated an “M-shaped” fluctuation tendency. The spatial distribution of O₃ presented positive associations and characteristics of significant spatial agglomeration. High-value areas of O₃ dominated in the Beijing-Tianjin-Hebei, Central Plains, and Shandong Peninsula. (2) The direct effect of the influencing factors was ranked as follows: per capita GDP > PM_2.5 concentration > proportion of the tertiary industry > proportion of the secondary industry > SO₂ concentration > NO₂ concentration. There was no significant direct effect of industrial SO₂ emissions and highway freight traffic on O₃. The intensities of the indirect driving factors’ effect were as follows: per capita GDP > proportion of the tertiary industry > proportion of the secondary industry > PM_2.5 concentration. The PM_2.5 concentration, the proportion of the secondary, and the tertiary industry exerted positive impacts on O₃, while per capita GDP was the opposite. The effects of SO₂ concentration, NO₂ concentration, highway freight traffic, and industrial SO₂ emissions on O₃ were not significant. This study reveals the complexity of regional O₃ pollution, and emphasizes the importance of regional joint prevention and control of atmospheric O₃ pollution from the perspective of social and economic linkages, providing a reference for inter-regional collaborative pollution control.





Spatiotemporal variations of carbon source-sink matching in the Beijing-Tianjin-Hebei urban agglomeration.

WANG Chao, XIE Hongyi, ZHANG Xinyu, ZENG Xueting

2025, 44(4):  1343-1354.  doi:10.13292/j.1000-4890.202504.041

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The Beijing-Tianjin-Hebei (BTH) urban agglomeration is characterized by rapid urbanization and coordinated development. It is important to clarify the changes of regional carbon sources and sinks, and to reveal the state and dynamics of regional carbon budget balance for achieving the “dual carbon” target and regional sustainable development. In this study, we used the static and dynamic analysis methods of carbon source-sink matching relationship to analyze the change of carbon budget balance state and the evolution of matching relationship in the BTH region. The results showed that carbon emissions due to human activities were higher than carbon sequestration from natural vegetation in the BTH region, indicating an obvious carbon deficit. The carbon balance index remained at 14%-27%. The net carbon emissions increased from 254.67 Mt in 2000 to the highest value of 678.08 Mt in 2013, and then tended to be stabilized as 668.98 Mt in 2019. The carbon balance matching varied greatly among the cities. From the static perspective, Zhangjiakou and Chengde were in “high carbon sequestration and low carbon emission” type in 2019, with an obvious carbon sink function. Among the other cities, six were in “low carbon sequestration and high carbon emission” type, four in “low carbon sequestration and low carbon emission” type, and one in “high carbon sequestration and high carbon emission” type. From a dynamic perspective, the 20-year evolution trajectory of carbon source-sink matching relationship in the BTH region was at an “emission increase-sink increase-unsustainable” type, and the evolution trajectory of a single year was highly variable. Among the various cities, the 20-year evolution trajectory of carbon balance matching relationship of Beijing was at an “emission increase-sink increase-sustainable” type, and its development path was more in line with the carbon neutrality target and low-carbon transition requirements.





Application of nanobubble technique on soil-crop system: A review.

ZHANG Feng, LI Shuxin, LIU Tianhao, ZHANG Peng, WANG Bin, LI Xiangnan

2025, 44(4):  1355-1362.  doi:10.13292/j.1000-4890.202504.036

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Nanobubbles (NBs) are tiny bubbles with size range of less than 1 μm. They have unique physicochemical properties, such as high stability, strong oxidative ability, and high mass transfer efficiency. NBs technique has been extensively applied in wastewater treatment, soil remediation, biomedicine, and agricultural irrigation. Little are known about the effects of NBs on the soilcrop system and the underlying mechanisms, although the available studies point towards it conferring the advantage of crop growth and stress resistance. Here, we reviewed the generation methods and properties of NBs, as well as the effects and potential mechanisms of NBs technique on soil-crop system. Further, we summarized the effects of NBs on soil physicochemical characteristics, microbial community structure, extracellular enzyme activities, seed germination, root development and leaf photosynthesis performance. Finally, we recommend the application and research directions of NBs technique in future crop production.

The difference between ecological integrity and ecosystem health and their application scopes.

LONG Xinyuan, HE Ping

2025, 44(4):  1363-1371.  doi:10.13292/j.1000-4890.202504.006

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Ecological integrity and ecosystem health are important goals of ecosystem management. The two concepts are frequently confused and misapplied in assessment work. As a result of the comparative analysis, both concepts differ in five aspects: concept connotation, management objectives, value orientation, reference benchmarks, and assessment methods. (1) Ecological integrity emphasizes naturalness, while ecosystem health emphasizes sustainability and social values. (2) The goal of ecological integrity is to maintain a natural state without human disturbance, while ecosystem health aims for an ideal state based on social needs. (3) Ecological integrity is based on nature conservation values, while ecosystem health is based on utilitarian conservation values. (4) The reference benchmark for assessing ecological integrity is the natural or historical state undisturbed by human beings, while for ecosystem health, it is the optimal attainable state or the recognized state. (5) The assessment indices for ecological integrity include physical, chemical, and biological indicators, while the assessment of ecosystem health incorporates additional indicators, such as management and economic factors. Ecological integrity and ecosystem health share similar conceptual contexts and assessment logic, with overlaps between them. The former is applicable to natural ecosystems, while the latter is applicable to disturbed or restored ecosystems. The choice between them should be based on the differences in concept connotation, the ecoregions, the intensity of human interference, and the management objectives.





A review on the observation and estimation of evaporation over small water bodies.

2025, 44(4):  1372-1381.  doi:10.13292/j.1000-4890.202504.001

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Water bodies with size smaller than 1 km₂ occupy 40.2% of the total area of inland water bodies. The evaporation of small water bodies is one of the important processes in inland water cycle. However, evaporation over small water bodies is either ignored in water cycle studies or estimated based on the equation of large water bodies. Actually, the driving process and controlling mechanism for evaporation over small water bodies is significantly different from that over large water bodies. Meanwhile, there are significant technical difficulties and knowledge gaps in the observation and estimation of evaporation over small water bodies, due to the lacking of direct observation. The eddy covariance and isotopic mass balance methods are applicative to observe and estimate evaporation over small water bodies. Here, we reviewed the applications of these two methods, and focused on the difficulties and challenges. Furthermore, we evaluated the mechanisms underlying evaporation at different time scales based on the principle of conservation of energy, with emphasis on the impact of advectionentrainment process on evaporation. The technical challenges of the eddy covariance method for evaporation observation of small water bodies mainly include source signal pollution in source regions and spectrum correction, while the key issue for isotopic method is the accurate quantification of kinetic fractionation factor under natural conditions. The size of signal source region of evaporation with eddy covariance observation over small water bodies is around hundreds of meters, while the isotopic mass balance methods could be used over the whole water bodies. We concluded that evaporation over small water bodies could be observed more accurately with the combination of the two methods, which would facilitate quantifying the contribution to the regional and global water cycle.





Classification of citrus orchard management modes based on resource quality and ecological value: A case study in Xinfeng County, Jiangxi Province.

PEI Wei, GAO Hong, CHEN Guishen, FENG Zhe, CHENG Feng, WU Kening

2025, 44(4):  1382-1392.  doi:10.13292/j.1000-4890.202504.013

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Garden is an important type of natural resources with both production and ecological functions. The implementation of differentiated management for the intensity of production and ecological functions is an important means to effectively protect and utilize garden resources. In this study, the orchard quality and ecological product value were used to characterize the production and ecological functions of orchards in Xinfeng County, Jiangxi Province. Moreover, the spatial differentiation characteristics were described. The random forest model was used to explore the importance of factor characteristics. Pearson correlation analysis was used to explore the correlation between orchard quality and ecological product value. Based on such relationship, differentiated management modes were proposed. The results showed that: (1) The value of ecological products per unit of citrus orchards showed a trend of higher in the surrounding areas and lower in the middle areas. (2) The overall quality of citrus orchards was high, with a distribution pattern of higher in the middle areas and lower in the surrounding areas. (3) There was a negative correlation between orchard quality and unit ecological product value. (4) The patches of citrus orchards were divided into four management types: compound key type, quality potential type, ecological potential type, and transformation and upgrading type. The corresponding management measures and development suggestions were put forward. There are trade-offs between the quality of citrus orchards and the value of ecological products in Xinfeng County. Decision makers should use the existing orchard grading evaluation to control the overall development direction of orchard quality, prioritize the development of areas with good soil texture and high organic matter content, reduce human interference, and optimize road construction.





Estimation and spatial distribution of carbon sink capacity in terrestrial ecosystems: A case study of three counties in southwest Jiaxing.

GAN Jing, ZHU Peilu, YANG Ying

2025, 44(4):  1393-1408.  doi:10.13292/j.1000-4890.202504.014

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Global climate change is becoming increasingly serious, and thereby green and low-carbon transformation is imperative. Quantification of terrestrial ecosystem carbon sink capacity is helpful to acquiring detail information about carbon sink resources, identifying the important spaces for carbon sink, and formulating strategies for enhancing carbon sink capacity. We evaluated carbon sink capacity of three counties in southwest Jiaxing based on the two factors, namely carbon storage and net ecosystem productivity. We further explored the differences in carbon sink capacity under different land use patterns. The results showed that the total carbon storage of the three counties in southwest Jiaxing was 1.54 Tg, with an average carbon density of 35.06 t·hm^-2. The high-value areas were the mountain forest land in the south and the land for economic crops in the north. The closer to the city center, the lower the carbon storage and carbon density. The average net ecosystem productivity was 463.34 g·m^-2·a^-1. The carbon source areas were mainly concentrated near the urban built-up areas and along the Qiantang River in the south, while the areas with high carbon sink values were mainly located in the southern mountain forest lands and some scattered woodlands in Haiyan County. Overall, the ranking of carbon sink capacity of land use types was forest land > land for economic crops > land for green and open space. The higher the degree of fragmentation, decentralization and marginalization, the lower the carbon sink capacity of terrestrial ecosystems. Strategies for enhancing carbon sink capacity were proposed for different land use types.