Table of Content

10 December 2024, Volume 43 Issue 12

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Influences of heavy metal contamination on soil fungal communities in a typical coal-based industrial park.

LIU Di, SU Chao, XIE Rong, LIU Yong

2024, 43(12):  3537-3544.  doi:10.13292/j.1000-4890.202412.043

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Soil microbial communities can be affected by heavy metal contamination induced by the coal-based industrial activities. We analyzed the differences of soil physicochemical properties, heavy metal concentrations and enzyme activities surrounding different coal-based industrial plants (coal mining industry, coal preparation industry, coal-based chemical industry, coal-fired power industry) in a typical coal-based industrial region in Shanxi Province. Soil samples from farmland and parks away from all the industrial plants were collected as references. We identified the composition of soil fungal communities based on high-throughput sequencing technology. The results showed that the contents of Cr, Ni, Cu, Zn, As, Cd, Pb and Hg were higher than the background values of corresponding elements in soils in Shanxi Province, and that the Cd and Pb contents around the coal preparation plants were the highest. The activities of cellulase and alkaline phosphatase displayed significant differences among different plants, with soil cellulase activity being the highest around the coal-based chemical plant. Ascomycota and Basidiomycota were the dominant fungal phyla with the largest relative abundance. The relative abundance of the dominant fungal phyla was significantly different across different plants. Ascomycota was the predominant fungal phylum surrounding the coal-based chemical plants, with the greatest relative abundance (79.30%). Results of redundancy analysis, variance partitioning analysis and Spearman correlation analysis showed that soil fungal community structure was significantly positively correlated with Cd content, total nitrogen content, and alkaline phosphatase activities (P<0.05), with Cd content having the strongest effect on soil fungal community.





Effect of combined application of chemical and organic fertilizers on the contribution of bacterial and fungal N₂O emissions.

ZHOU Ning, SHANG Wending, LI Huawei, WANG Hao, CHE Zhao, LI Xiaoxiao, SONG He

2024, 43(12):  3545-3552.  doi:10.13292/j.1000-4890.202412.042

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To investigate the effects of fertilizer types (organic and chemical fertilizer) on nitrous oxide (N₂O) emissions from soil bacteria and fungi, we conducted a long-term experiment with four treatments, including no fertilization (CK), chemical fertilizer (T1), combined application of chemical and organic fertilizers (T2), and organic fertilizer (T3). We measured soil physical and chemical properties, and the contributions of N₂O emissions from bacteria and fungi. The abundance and structure of bacterial and fungal communities were analyzed by real-time PCR and high-throughput sequencing. The results showed that, compared with T1, T3 significantly increased N₂O emissions from bacteria by 31.34% and decreased N₂O emissions from fungi by 17.11%, while T2 significantly increased overall N₂O emissions by 57.83%, increased N₂O emissions from bacteria by 47.83%, and from fungi by 72.37%. The results of PLS-SEM modeling showed that N₂O emission from bacteria was mainly affected by bacterial community structure rather than their abundance, and by soil pH and electrical conductivity as well. The N₂O emission from fungi was mainly affected by fungal community structure. The proportion of relative abundance of Ascomycota and Basidiomycota was the key to influence the N₂O emission from fungi. Our results highlight that it is necessary to consider not only the characteristics of fertilizer, but also the effects of physicochemical properties such as soil pH and electrical conductivity when studying the effects of fertilizer type on N₂O emissions from bacteria and fungi.





Hyperspectral estimation of soil phosphorus content in mining area based on CARS-CNN.

ZHAO Xinghui, FENG Xueqi, NIE Xiaojun, ZHANG Yan, GUO Erhui

2024, 43(12):  3553-3562.  doi:10.13292/j.1000-4890.202412.011

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Soil phosphorus management is an issue that be worthy of attention in the improvement of cultivated land quality and the protection of water environment in coal mining areas. With hyperspectral remote sensing technology, exploring the accurate inversion method of soil phosphorus content can facilitate the monitoring of cultivated land soil phosphorus content in coal mining areas. In this study, we collected soil samples of cultivated land from the Macun mining area in Jiaozuo, Henan Province, and got the spectral data of soil samples by a portable ground object spectrometer. The original spectrum and its decomposed data by continuous wavelet transform (CWT) were selected as independent variables, while the feature wavebands were selected by the competitive adaptive reweighted sampling (CARS). The modeling effects of deep learning \[convolutional neural network (CNN)\] and common machine learning methods \[random forest (RF) and BP neural network (BPNN)\] were compared and analyzed. Results showed that CWT method enhanced the correlation between spectral reflectance and soil phosphorus content, and thus improved the model accuracy. CNN exhibited a strong feature of learning ability, and its prediction accuracy was much higher than those of BPNN and RF. Combining the CARS algorithm for feature wavebands screening and the CNN for feature extraction could further improve the efficiency of the model. The relative percentage difference (RPD) of the optimal model of soil total phosphorus and available phosphorus content were increased by 7.53 and 1.25, respectively. Among the wavelet transform L₁-L₁₀ data filtered by CARS, L₉-CARS-CNN model had the highest accuracy in the soil total phosphorus and available phosphorus. The RMSE and RPD of its verification set were 1.33 mg·kg^-1 and 25.29 for soil total phosphorus, and 1.52 mg·kg^-1 and 11.95 for available phosphorus, respectively. Therefore, combining the CARS for feature wavebands extraction and the CNN for model building can accurately retrieve soil phosphorus content, which will have broad application prospects.





Vertical patterns of soil multifunctionality as affected by biological soil crusts in Gurbantunggut Desert.

LIU Chaohong, LU Yongxing, GUO Hao, YANG Jungang, ZHANG Shihang, ZHANG Lingwei, LIU Xuejun, ZHANG Yuanming, ZHOU Xiaobing

2024, 43(12):  3563-3570.  doi:10.13292/j.1000-4890.202412.001

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As an important part of desert ecosystems, biological soil crusts (BSCs) play an extremely important role in the stability and function of desert soils. We analyzed the influence of BSCs on soil multifunctionality (SMF) in different soil layers and main driving factors. This study was carried out in the Gurbantunggut Desert, and two types of BSCs (algal-lichens and mosses) were used as research objects (with bare sand as the control). Soil organic carbon (TOC), total nitrogen (TN), total phosphorus (TP), inorganic nitrogen (IN) and soluble organic nitrogen (DON) were selected to calculate the SMF index by the mean method. Each functionality such as TOC, TN, TP, IN and DON increased with the development of BSCs and decreased with soil depths. The SMF of bare sand ranged from -0.96 to 0.55, showing an increasing trend in the 0-5 cm soil depth and a decreasing trend in 5-20 cm soil depth. The SMF of mixed algal-lichen crusts and moss crusts was at -0.53 to 1.33 and -0.43 to 2.05, respectively, and showed a decreasing trend in the 0-20 cm soil depth. The SMF of the three types of BSCs tended to be stable in the 20-100 cm soil layer. The SMF showed an overall trend of moss crusts > mixed algal-lichen crusts > bare sand in the 0-20 cm and 0-100 cm soil layer. Soil pH, soil water content, and soil urease activity were closely related to the vertical changes of SMF. Soil pH and soil water content had significant negative effects on SMF, while soil urease activity had significant positive effects. Soil particle size was one of the main factors affecting SMF, with negative relationship between medium-sized sand contents and SMF, and positive relationship between coarse sand contents and SMF. Therefore, the development of BSCs significantly improved soil single functionality and soil multifunctionality. The influence of BSCs on soil multifunctionality was mainly concentrated in the range of 0-20 cm in the surface soil, with little effect on the deeper soil. While BSCs affected soil multifunctionality, other functions also changed.





Grain size characteristics of soil on typical underlying surfaces in Mu Us Sandy Land.

ZHANG Lingguang, CHENG Long, SUN Yingtao, PANG Yingjun, LI Jia, JIA Xiaohong, FEI Bingqiang, XIU Xiaomin, YIN Jie, WU Bo

2024, 43(12):  3571-3579.  doi:10.13292/j.1000-4890.202412.030

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To reveal the soil particle size distribution characteristics of different underlying surfaces of Mu Us Sandy Land, we analyzed soil grain size composition, parameters and particle size distribution curves of different underlying surfaces (fixed sandy land, semi-fixed sandy land, shifting sandy land, and lowland) by collecting soil samples at 0-5, 5-10 and 10-20 cm depth. The results showed that soil sand content in sandy lands was nearly 90%, being 30% higher than that in lowland. The content of very fine sand and clay+silt was between 3% to 15%, being more than 25% lower than that in lowland. There was no significant difference in sand content among fixed, semi-fixed and shifting sandy land. The content of very fine sand and clay+silt of soil in fixed sandy land was 10%-15%, being more than 7% higher than that in semi-fixed sandy land and shifting sandy land. The mean size of soil particles was 2.22 Φ, the standard deviation was 0.86 Φ, and the skewness was 0.14, which means the particle size shows a skew-normal distribution and poor sorting ability. The grain size parameters of soil in sandy lands were smaller than that in lowland. The particle size of sand dunes with different fixed degrees was in an order of shifting and semi-fixed sand dunes < fixed sand dunes. The particle size interval of the saltation in sandy lands and lowland was 1-3.5 Φ and 1-6 Φ, respectively. The sorting of saltation in lowland was worse than that in sandy lands, while the sorting of suspension was better. There were significant differences in grain size characteristics of soil among different underlying surfaces in Mu Us Sandy Land. The results could provide a theoretical basis for guiding desertification combating by classification at different zones in semi-arid regions.





Soil nutrient properties in the distribution area of the extremely small population of Oncodostigma hainanense.

HONG Wenjun, WANG Bingyu, ZENG Dehua, HUANG Yongping, LIU Jun

2024, 43(12):  3580-3586.  doi:10.13292/j.1000-4890.202412.005

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Oncodostigma hainanense, a wild plant species with extremely small population, is concentrated in Sanya and Baoting, Hainan Province. We compared the differences of soil nutrient contents in different habitats of O. hainanense in Ganshiling Provincial Nature Reserve, Yalong Bay Tropical Paradise Forest Park, and Qixianling Hot Springs National Forest Park in Baoting Li and Miao Autonomous County, and examined the effects of soil properties on the distribution characteristics of O. hainanense. The results showed that the structure of the three O. hainanense populations was unstable, indicating a declining trend, with the highest population density in Qixianling Forest Park (375 individuals per hectare). Soil in the distribution areas was characterized by acidity, with pH values ranging from 5.54 to 6.17. Organic matter content, available nitrogen content, and total nitrogen content were relatively high in the soils, while total potassium, total phosphorus, and available phosphorus contents were relatively low. Soil microbial biomass carbon ranged from 225.28 to 318.33 mg·kg^-1, and soil microbial biomass nitrogen ranged from 137.34 to 165.25 mg·kg^-1. Ganshiling Nature Reserve exhibited the highest soil catalase activity (4.53 mL·g^-1·h^-1), while Yalong Bay Forest Park had the highest soil acid phosphatase and urease activities (9.78 mg·g^-1·d^-1 and 0.84 mg·g^-1·d^-1, respectively). PCA analysis results showed that soil samples from each site could be well clustered into one group, and the response of each distribution site to soil factors was significant. Soil nutrients were significantly correlated with microbial biomass and enzyme activities, indicating that soil factors played a key role in driving population structure and growth of O. hainanense.





Change in soil microbial necromass in a broad-leaved evergreen forest along altitudinal gradient in Yongde Snow Mountain, southwest Yunnan.

XU Fandi, YANG Yuchun, CHEN Yanxuan, LI Cong, WU Jiangchong, WANG Tongli, LI Shuaifeng, SU Jianrong

2024, 43(12):  3587-3594.  doi:10.13292/j.1000-4890.202412.010

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Microbial necromass plays an important role in the formation of soil organic carbon (SOC). However, the change of microbial necromass along altitudinal gradient remains unclear. In this study, we analyzed the differences of soil physicochemical properties, microbial necromass (topsoil 0-20 cm), and stand characteristics along an altitudinal gradient (1200, 1700, and 2200 m) in a broad-leaved evergreen forest in Yongde Snow Mountain, Yunnan Province, aiming to reveal the regulatory mechanism of microbial necromass accumulation along the altitudinal gradient. The results showed that microbial necromass was 15.36 g·kg^-1 in the broad-leaved evergreen forest and that its contribution to SOC was 24.09%. The contribution of fungal necromass to SOC (20.36%) was higher than that of bacterial necromass (3.73%). Fungal, bacterial, and microbial necromass increased significantly with increasing altitude. There was no significant difference in the contribution of fungal and microbial necromass to SOC along the altitudinal gradient. In addition, woody species composition showed significant effects on fungal and microbial necromass. Microbial necromass increased with increasing soil nutrients, but increased significantly with decreasing woody species richness. Furthermore, higher SOC, soil total nitrogen, soil available nitrogen, and soil water content, and lower soil pH could promote the accumulation of microbial necromass. Soil nutrient, altitude, and woody species diversity were the important factors affecting microbial necromass. Therefore, altitude promoted the accumulation of microbial necromass but did not increase its contribution to SOC.





Niche and interspecific association of dominant species in shrub layers of typical forest communities in the western part of the Qinling Mountains.

HU Ningning, CUI Yuxin, SUN Meng, KANG Bing

2024, 43(12):  3595-3604.  doi:10.13292/j.1000-4890.202412.023

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Understanding niche characteristics and interspecific relationships of dominant populations in the shrub layer of forest communities can provide scientific basis for the conservation and management of forest resource. In this study, we characterized the niche of the dominant species of shrub layer in typical forest communities in the western part of the Qinling Mountains by Levins niche breadth, Shannon niche breadth and Levins niche overlap indices. The interspecific relationships were analyzed by using the variance ratio method, χ² test, association coefficient (AC), and Pearson correlation test. The results showed that among 190 species pairs formed by the 20 dominant species in the shrub layer, Lonicera fragrantissima had the largest niche breadth and Corylus heterophylla was the smallest. The mean value of niche overlap was 0.32. Species pairs with small niche overlap were predominated, indicating a high degree of differentiation among the dominant species in the shrub layer, which was conducive to the formation of species diversity. The dominant populations in the shrub layer showed significant positive associations, indicating that forest communities were in a relatively stable stage of late succession. The results of both χ² test and Pearson correlation test showed that the positive and negative association ratios were greater than 1, and the majority of species pairs were non-significant associations, indicating an independent distribution pattern among species. The niche overlap index was positively correlated with the association coefficient (AC) and Pearson correlation coefficient.





Evaluating the effects of Pinus massoniana and Castanopsis hystrix mixing on the productivity and temporal stability of Pinus massoniana based on tree ring analysis.

LI Qiongying, CHEN Renjie, LI Zewei, SHEN Weijun

2024, 43(12):  3605-3614.  doi:10.13292/j.1000-4890.202412.025

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Mixed-species plantations have emerged as an effective measure for maintaining forest productivity and ecological services over recent years. However, current research predominantly focuses on comparing productivity differences between two distinct periods, providing limited insights into the comprehensive mixing effects across the entire lifespan of trees. In this study, we employed dendrochronological methods to assess the productivity of the monoculture of Pinus massoniana and an even-aged mixture of P. massoniana and Castanopsis hystrix grown under similar environmental conditions and management regimes. Our objectives were to document stand dynamics and to compare the productivity and temporal stability of mixed plantation versus monoculture of P. massoniana. The results showed that, after 39 years of mixing, the productivity of P. massoniana, measured as basal area increment (BAI), in the mixed plantation was 36.8% lower than that in monoculture. Furthermore, the temporal stability of productivity of P. massoniana in the mixed plantation was lower than that in the mixed plantation across all age classes. The mixing effects of P. massoniana were negative except in drought years. Such effects varied in different age classes, suggesting that the strength of interspecific complementarity of P. massoniana and C. hystrix in the even-aged mixed plantation was lower than that of interspecific competition. Overall, our results emphasize the importance of considering functional traits and selecting appropriate mixing modes when establishing mixed-species forests. To achieve sustainable management of mixed forests, timely thinning or release cutting is recommended to mitigate the strong light competition among trees.





Seasonal variations in non-structural carbohydrate of Pinus tabuliformis and Pinus densiflora in Horqin Sandy Land.

WANG Xin, WANG Kai, ZHANG Risheng, LIU Chang

2024, 43(12):  3615-3623.  doi:10.13292/j.1000-4890.202412.038

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Seasonal variations of non-structural carbohydrate (NSC) contents in different organs of 40-year-old Pinus tabuliformis and Pinus densiflora were analyzed in Horqin Sandy Land, and the carbon allocation and utilization strategies of the two species were compared, which is of great significance to the selection of afforestation tree species and sustainable management of protective forests in Horqin Sandy Land. Results showed that starch contents in branches and roots of P. densiflora were higher than those of P. tabuliformis in April. From April to June, soluble sugars and starch contents of P. tabuliformis decreased in 1- and 2-year-old needles, but varied less in 1- and 2-year-old branches; the content of soluble sugars increased while starch content remained stable in roots. The contents of soluble sugars, starch and NSC in 1- and 2-year-old needles and branches, and roots of P. densiflora decreased. From June to August, for P. tabuliformis, soluble sugars contents increased in current-year branches and needles but decreased in 1-year-old branches and needles, and roots; however, for P. densiflora, contents of soluble sugars, starch and NSC, and ratios of soluble sugars to starch in needles with 3 age classes remained stable, while soluble sugars contents increased in current-year branches but decreased in roots. From August to October, soluble sugar content decreased in roots of both species, whereas it remained unchanged in P. tabuliformis branches, but increased in P. densiflora branches. These results indicated that P. tabuliformis had relatively lower NSC storage for growth. P. densiflora had higher NSC storage during the dormant period, resulting in faster growth of branches and needles, and thus more NSC production during the growing period, and more NSC distribution to branches and roots for growth at the late growth period, which can be better adaptive to the habitat of Horqin Sandy Land.





Seasonal variations in non-structural carbohydrates of Populus alba × P. berolinensis and Ulmus pumila in Horqin Sandy Land.

WANG Kai, WANG Xin, ZHANG Risheng, LIU Chang

2024, 43(12):  3624-3631.  doi:10.13292/j.1000-4890.202412.039

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We analyzed seasonal changes of non-structural carbohydrate (NSC) contents in different organs (leaf, branch and root) and leaf litter of an introduced species Populus alba ×P. berolinensis and a native species Ulmus pumila in Horqin Sandy Land. Carbon allocation and storage strategies of those two species were compared. Results showed that for P. alba × P. berolinensis, contents of soluble sugar and NSC decreased and then increased while starch content gradually decreased in leaves over season; soluble sugar content and ratio of soluble sugar to starch increased and then dropped, starch content decreased and subsequently rose in branches and roots over season. In contrast, for U. pumila, NSC content in branches remained unchanged while contents of soluble sugar, starch and NSC in roots firstly decreased and then increased from spring to autumn. Soluble sugar contents in leaves of P. alba × P. berolinensis were higher than those of U. pumila in spring and summer. Except for branches in autumn, starch contents in all organs of U. pumila were higher than that of P. alba × P. berolinensis, and the ratio of soluble sugar to starch was lower than that in P. alba × P. berolinensis. Contents of soluble sugar, starch, and NSC in leaf litters of U. pumila were higher than those of P. alba × P. berolinensis. Therefore, NSC is mainly used for growth and consumption, implying stronger competition for P. alba × P. berolinensis in the community. NSC is more stored as starch, which may contribute to the stronger stress resistance of U. pumila and facilitate the carbon cycle between plant and soil.





Nitrogen deposition and increased precipitation and their coupling effects on nonstructural carbohydrates allocation of Ulmus pumila seedlings.

WANG Kai, XIN Hongbin, LIU Chang, LYU Linyou, LIU Jianhua

2024, 43(12):  3632-3639.  doi:10.13292/j.1000-4890.202412.045

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To elucidate the response of non-structural carbohydrates (NSC) of Ulmus pumila seedlings to nitrogen deposition and increasing precipitation, we analyzed concentrations of soluble sugar, starch, and NSC in different organs (leaf, branch, stem, coarse root and fine root) under a full-factorial experiment, i.e., four levels of nitrogen deposition (0, 5, 10, and 15 g N·m^-2·a^-1) and three precipitation levels (natural precipitation, 50% and 100% increase in precipitation) with randomized block design. The results showed that increased precipitation caused the decrease of soluble sugar concentrations in branches, stems, coarse roots and fine roots, but did not affect leaf soluble sugar concentration under treatment without nitrogen addition. With increasing nitrogen deposition, under natural precipitation, soluble sugar concentrations increased in leaves, branches and stems but decreased in fine roots. There were pronounced interactions between nitrogen deposition and increased precipitation on NSC concentrations in each organ of U. pumila seedlings. Under 15 g N·m^-2·a^-1 nitrogen addition treatment, compared to natural precipitation, starch concentrations in each organ decreased under 50% increase in precipitation, while soluble sugar, starch and NSC concentrations in branches, stems and coarse roots decreased under 100% increase in precipitation. Therefore, nitrogen deposition would increase NSC storage of U. pumila seedlings, and 50% increase in precipitation is conducive to promote seedling growth.





Effect of fertilization on the early process of Phyllostachys edulis litter decomposition.

LUO Huiying, LIU Yong, SU Wenhui, CHEN Jiahong, FAN Shaohui, SUN Yutong, LONG Yongmei, JING Xiong

2024, 43(12):  3640-3647.  doi:10.13292/j.1000-4890.202412.021

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Litter is the main source of soil organic matter, and its decomposition can be affected by various factors. As an important measure for high-yield management of bamboo forests, fertilization affects the formation of organic matter and nutrient cycling. To investigate the impacts of different nitrogen fertilization levels on the early processes of Phyllostachys edulis litter decomposition under the conditions of mixed applications of nitrogen (N), phosphorus (P), and potassium (K) fertilizers, an experiment was conducted with a fixed P and K application level and four N application levels: no N application (CK), low N (242 kg·hm^-2, LN), medium N (484 kg·hm^-2, MN), and high N (726 kg·hm^-2, HN). The effects of fertilization on mass loss, nutrient return, and stoichiometric ratio of litter during decomposition were examined. The results showed that after 13 months of decomposition, the rate of litter mass remaining was 67.5%-70.8% across various nitrogen application levels, which was not affected by fertilization. There were no significant differences in carbon content of decomposing litter among different treatments. Fertilization significantly promoted the enrichment of N and P in litter, which was 39.97%-45.76% and 64.25%-75.70% higher than that in the CK, respectively. Hemicellulose and cellulose contents decreased to different extents, with hemicellulose decomposing faster. The reduction of hemicellulose content was in an order of MN (50.13%) > LN (49.25%) > HN (42.44%) > CK (39.00%), while the reduction of cellulose content was LN (36.86%) > MN (31.98%) > HN (26.89%) > CK (24.41%). The LN and MN treatments significantly promoted the decomposition of total cellulose, while different treatments had no significant effect on lignin. In conclusion, different N fertilization levels did not affect litter mass loss at the early stage of decomposition, regulated nutrient release and the decomposition of carbon components, and significantly enhanced N and P enrichment of litter. LN and MN treatments effectively promoted the decomposition of total cellulose. All treatments did not affect the lignin and total carbon contents of litter.





Photosynthetic response of Spartina alterniflora to shading and mowing.

LYU Jiangrong, YOU Huiming, ZHOU Yasheng, LIANG Jingwen, YOU Weibin, HE Dongjin

2024, 43(12):  3648-3655.  doi:10.13292/j.1000-4890.202412.026

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To reveal the photosynthetic response mechanism of Spartina alterniflora to shading and mowing, we investigated the effects of different treatments (0% shading + no mowing, 0% shading + mowing, 30% shading + no mowing, 30% shading + mowing, 50% shading + no mowing, 50% shading + mowing, 70% shading + no mowing, 70% shading + mowing, 90% shading + no mowing, 90% shading + mowing) on the photosynthetic characteristics of S. alterniflora. Seven photosynthesis-related indices were measured, including daily average photosynthetic rate, maximum net photosynthetic rate, light compensation point, dark respiration rate, chlorophyll a, chlorophyll b, and carotenoids. The results showed that shading significantly inhibited daily average photosynthetic rate (P<0.01), which decreased with increasing shading intensity. The contents of chlorophyll a and carotenoids increased significantly with increasing shading intensity (P<0.01). Mowing significantly inhibited daily average photosynthetic rate, chlorophyll a, chlorophyll b, and carotenoid content (P<0.01). Shading and mowing interacted to affect light compensation point of S. alterniflora (P<0.05), but did not affect other indices. Principal component analysis revealed that the combination treatment of 90% shading and no mowing exhibited the strongest inhibition on photosynthetic activities of S. alterniflora.





Phosphorus transformation in rhizosphere of four green manure crops grown on lateritic red soil and calcareous soil.

PENG Song, ZHU Xiaohui, HUANG Zhuoqin, RUAN Wenliang, LU Xing, LIN Dongjiao, DENG Lansheng, LIANG Cuiyue, TIAN Jiang, TIAN Jihui

2024, 43(12):  3656-3664.  doi:10.13292/j.1000-4890.202412.016

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We investigated rhizosphere phosphorus (P) dynamics of four green manure crops in lateritic red soil and calcareous soil, aiming to provide a scientific basis for maximizing the biological potential of green manure crops to mobilize soil P. A pot experiment was conducted to explore the effects of planting Raphanus sativus (LB), Vicia angustifolia (ZHS), Desmodium intortum (SMH), and Stylosanthes guianensis (ZHC) on the rhizosphere soil pH, acid phosphatase activity and phosphorus fractions in lateritic red soil and calcareous soil. In both soil types, Raphanus sativus had significantly higher biomass, P concentration, and P-use efficiency than the other crops. Except for Stylosanthes guianensis, planting green manure crops moderately increased soil pH and acid phosphatase activity in both soils. In lateritic red soil, the four green manure crops significantly depleted total inorganic P, labile inorganic P, moderately labile inorganic P, stable inorganic P, and residual P. In contrast, planting green manure crops (except Desmodium intortum) significantly depleted total organic P in the calcareous soil. Results of random forest analysis indicated that stable inorganic P, labile inorganic P, moderately labile inorganic P, and labile organic P were the most important predictors of plant P uptake in lateritic red soil, while soil moderately labile inorganic P, stable organic P, stable inorganic P, and acid phosphatase activity showed significant impacts on plant P uptake in calcareous soil. In lateritic red soil, different green manure crops tended to utilize various forms of inorganic P, while in calcareous soil, acid phosphatase-mediated turnover of soil organic P played an important role in plant P uptake. Taken together, Raphanus sativus and Vicia angustifolia showed significant P mobilizing potential in both soils and can serve as suitable crop species for improving the quality of typical degraded soils in South China.





Effects of different crops on water infiltration in typical black soil water erosion area.

SUN Shunan, LI Zehong, HOU Ruixing, WANG Lei, YANG Kejun, FU Jian, XU Chao, MIAO Yu

2024, 43(12):  3665-3673.  doi:10.13292/j.1000-4890.202412.014

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To elucidate the relationship between crops and soil erosion, we examined the effects of two crops, sorghum Keza 18 (SO) and maize Keyu 19 (MA), on soil water infiltration characteristics, through the analysis of crop roots, soil physical properties and infiltration rate in Keshan County, Heilongjiang Province, a water erosion zone in Northeast China. The results showed that soil bulk density of 0-20 cm layer in SO treatment was significantly increased by 6.15% compared to the MA treatment. The total porosity and non-capillary porosity were significantly decreased by 5.93% and 15.63%, respectively. The saturated water capacity and field water capacity decreased significantly by 6.38% and 6.11%, respectively. Soils under both SO treatment and MA treatment were dominated by 0.25-2 mm particle size aggregates. The mean weight diameter and geometric mean diameter of soil in SO treatment were significantly reduced by 29.57% and 4.60%, respectively, compared to MA treatment. In the soil layers of 0-20, 20-40, 40-60 and 60-80 cm, root weight density of MA treatment was 1.67, 2.46, 4.52, and 2.27 times of that of SO treatment, respectively. The initial infiltration rate, stable infiltration rate, saturated hydraulic conductivity and average infiltration rate of SO treatment were significantly reduced by 19.11%, 15.50%, 15.63%, and 14.86%, respectively, compared with MA treatment. The Kostiakov model, Horton model and Philip model were used to simulate the soil infiltration processes. The Horton model had the largest R² and the best fitting effect on the soil infiltration processes. The infiltration rate was significantly negatively correlated with bulk density, and positively correlated with other indices. Furthermore, root system of dwarf sorghum grown in this region was shallower than that of maize, with a larger capacity and slower infiltration rate, which easily leads to surface runoff and increases the risk of water erosion. Our results can provide data reference for the prevention and control of soil erosion in this region.





Meta-analysis of the effects of plastic film mulching on peanut yield and water-nitrogen utilization in northern China.

XUE Depeng, YANG Luhua, SHEN Xiaojun, YUAN Yingwei, WU Kuijun

2024, 43(12):  3674-3683.  doi:10.13292/j.1000-4890.202412.009

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A meta-analysis was conducted to examine the effects of plastic film mulching on peanut yield, water use efficiency, and nitrogen partial factor productivity in northern China from 1981 to 2021. The differences in yield-enhancing effects of plastic film mulching were mainly explored under various influencing factors through subgroup analyses. The results showed that plastic film mulching increased peanut yield, water use efficiency, and nitrogen partial factor productivity by 20.0%, 36.2%, and 20.8% (P<0.05), respectively. Results of random forest analysis showed that climatic conditions were the most critical factor impacting the yield-enhancing effect of plastic film mulching in northern China. Subgroup analyses showed that plastic film mulching had the most significant effect on peanut yield enhancement in Northwest China, followed by Northeast China, and the lowest in North China, with yield increases of 35.4%, 21.6%, and 15.9% (P<0.05), respectively. The yield of peanut under plastic film mulching in northern China increased the most (by 58.9%) between 1991 and 2000, and the lowest (by 14.8%) between 2011 and 2021. Under natural conditions of annual precipitation of 400-600 mm, annual average temperature <12 ℃, sandy loam soils or soils with an organic matter content of <20 g·kg^-1, plastic film mulching had stronger yield-enhancing effect. In terms of field management measures, peanut yields increased more significantly under plastic film mulching when applied in water permeable film, spring sowing, flatten culture, planting density <150000 holes·hm^-2, split fertilization, nitrogen application < 90 kg·hm^-2, phosphorus application < 60 kg·hm^-2 or potassium application > 210 kg·hm^-2. Therefore, peanut mulching should be adopted in the arid, semi-humid, and low temperature areas in northern China. The effect of mulching on yield increase should be more efficient by adjusting field management measures. This study can provide theoretical guidance for peanut mulching planting in northern China.

Effects of simulated nitrogen deposition on N and P stoichiometric characteristics of soybean under drought stress.

YAO Xingzhou, WANG Yan, WANG Weiping, WU Jianing, ZHAO Tianhong

2024, 43(12):  3684-3692.  doi:10.13292/j.1000-4890.202412.015

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Investigating the impact of increased nitrogen (N) deposition under drought stress on the ecological stoichiometry of soybean (Glycine max) organs is pivotal for predicting ecological processes and guiding sustainable agricultural development. We explored the effects of simulated nitrogen deposition on N and phosphorus (P) stoichiometry of different organs of soybean cultivar “Tiefeng 29” following drought stress in a pot experiment. There were eight treatments with two water levels: normal moisture (W, 75%±5%), drought (D, 35%±5%), and four N addition levels: CK, LN, MN, HN (nitrogen application was divided into three times, with nitrogen addition amount totaling 0, 50, 100, 150 kg·hm^-2·a^-1). The results showed that the interaction between drought stress and N deposition significantly affected N and P concentration and the N/P ratio in roots, stems, and leaves. Compared with the  CK-D treatment, with the increase of N addition level, root N concentration gradually decreased after one time of N addition, and significantly decreased by 19.3% in the HN-D treatment. The stem P concentration first increased and then decreased, and significantly increased by 38.2% in the LN-D treatment. The leaf P concentration gradually increased, and significantly increased by 31.2% in the HN-D treatment. After two times of N additions, root N concentration was significantly lower than that of CK-D treatment, and there was no significant difference among various N treatments (LN, MN, HN). The stem P concentration gradually decreased, and significantly decreased by 18.9% in the HN-D treatment. The leaf N concentration increased first and then decreased, and significantly increased by 18.5% in the MN-D treatment. After three times of N additions, root N concentration decreased gradually, and significantly decreased by 19.7% in the HN-D treatment. Stem N concentration increased first and then decreased, and significantly decreased by 22.6% in the HN-D treatment. Leaf P concentration was significantly lower than CK-D treatment, and there was no significant difference among treatments (LN, MN, HN). Furthermore, after N application, in the power function relation of leaf N-P (N=βP_α, both α and β are constants), α of W treatment was <1, α of D treatment was >1, with leaf N/P ratios exceeding 16. There was a significant relationship between root and stem N concentration, a highly significant relationship between stem and leaf N concentration, a highly significant positive correlation between root and leaf N concentration, and no significant relationship between stem N and P concentration. In conclusion, early N application can mitigate the negative effects of drought stress on soybean. However, as N deposition increases and the times of nitrogen application rises, soybean growth is limited by P availability.





¹⁵N tracer analysis of nitrogen use efficiency in sugarcane organs under reduced nitrogen fertilization.

CUI Tingting, WANG Jingyu, HU Baoqing, MAO Bing, LI Zhuoting, XU Qiangsheng, LI Tinghua

2024, 43(12):  3693-3701.  doi:10.13292/j.1000-4890.202412.017

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Clarifying the influence of reduced nitrogen fertilization on nitrogen uptake and utilization of sugarcane organs can provide scientific basis for rational fertilization in sugarcane production. Based on ¹⁵N tracer technique, a micro-plot field experiment was conducted to investigate the effects of three application levels of nitrogen fertilizers \[low level (N300): urea 300 kg·hm^-2; middle level (N400): urea 400 kg·hm^-2; high level (N500, the conventional nitrogen application): urea 500 kg·hm^-2\] on nitrogen uptake and utilization of leaves, stems and roots, and residual nitrogen rate of soil (0-10, 10-20, 20-40 cm) after topdressing and at stages of seedling, extension, and mature, respectively. The results showed that reduced nitrogen fertilization did not affect the accumulation of ¹⁵N in leaves and stems at stages of extension and mature. Generally, accumulated N concentration, accumulated ¹⁵N concentration, amount of N derived from fertilizer and amount of N derived from soil of sugarcane root were higher in N500 treatment than that in the other treatments at stages of topdressing, seedling, extension, and mature. At the stages of seedling, extension and mature, N uptake and fertilizer use efficiency of leaf, stem and root were higher in the N300 treatment than that in the other treatments. There were no significant differences of accumulated ¹⁵N concentration of soil at 0-10, 10-20, 20-40 cm layers among the three N treatments at extension stage. The N residual rate of 0-10, 10-20, 20-40 cm soil was higher in the N300 treatment than that in the other treatments at stages of topdressing, seedling, extension and mature. Collectively, reduced nitrogen fertilization is beneficial to improving fertilizer use efficiency of roots and stems, and consequently the yield of sugarcane.





Utilization of artificial alternative habitat by waterbirds in Shankou Mangrove National Nature Reserve, Guangxi,  southern China.

TIAN He, YANG Gang, ZHANG Minghui, HE Yaoyin, LIANG Miaomiao, LU Zhou, YU Lijiang

2024, 43(12):  3702-3709.  doi:10.13292/j.1000-4890.202412.046

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Waterbirds are an important component of the wetland ecosystems. Waterbirds can be used as biological indicators because they are highly sensitive to environmental changes. Shankou Mangrove National Nature Reserve of Guangxi, southern China is an important stopover site for migrant birds along the East Asian-Australasian Flyway. Due to the loss of natural wetlands, more and more waterbirds are forced to choose artificial wetlands as their alternative habitats. From 2016 to 2021, we investigated the richness and abundance of birds in four main habitats, including aquaculture pond, salt pan, grassland and farmland, to explore the utilization of alternative habitats by waterbirds in the reserve. The results showed that: (1) A total of 13 dominant and common waterbird species were found in the four alternative habitats, with the species richness in aquaculture ponds being the highest, and lowest in farmland habitat. (2) The diversity index and the abundance of waterbirds were dominated in aquaculture pond and salt pan habitats. (3) The generalized linear model showed significant differences in habitat utilization among waterbirds of different taxa. In conclusion, alternative habitats, especially the aquaculture pond and salt pan, play an important role in maintaining the waterbird populations in the reserve. The artificial alternative habitats should receive sufficient attention and effective protection in the future.





Effect of microhabitat on beta diversity of ground-dwelling arthropods community in an island-like swamp forest at Daxing’anling Mountains.

DING Min, YE Dong, LIU Zhitao, WANG Daoqi, LI Huiren, WEI Changlei, ZHAO Houkun, WANG Lizhong, LIN Yinghua

2024, 43(12):  3710-3716.  doi:10.13292/j.1000-4890.202412.032

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Island-like swamp forest is a unique ecosystem in the eastern Daxing’anling Mountains. Pitfall trap method was used to investigate ground-dwelling arthropod community and habitat characteristics. We analyzed the response of ground-dwelling arthropod community beta diversity to microhabitat characteristics in three typical island-like swamp forests, namely, pure larch forest (Larix gmelinii), pure birch forest (Betula platyphylla), and larch and birch mixed forest. A total of 544 arthropods, belonging to 5 classes, 14 orders, 67 families and 61 genera, were collected. The ground-dwelling arthropod communities were mainly dominated by Coleoptera, Diptera larvae, Hymenoptera, Aranea, and Collembola. Among them, the individual abundance and taxa (order) richness was the highest in the birch pure forest and the lowest in the larch pure forest. There were no significant differences in total beta diversity (β_sor) and species turnover (β_sim) and species nestedness (β_nes) components of ground-dwelling arthropod community in the three habitats, but there were differences in β_sim and β_nes components in the same taxa (P<0.05). The β_sim/β_sor ratio was greater than 50%, indicating that changes in ground-dwelling arthropod community diversity in the island-like swamp forests were mainly affected by species turnover, and the taxa with greater abundance had a greater impact on beta diversity. The diversity of ground-dwelling arthropod community was positively correlated with surface temperature and moisture (r²=0.120-0.128, P<0.01), major soil chemical properties (r²=0.229-0.230, P<0.01), and litter layer thickness (r²=0.148, P<0.01). Surface temperature and moisture, main soil chemical properties and vegetation characteristics together explained 11.03% of the variation of ground-dwelling arthropod community. However, 88.97% of the variation was not explained. Our results suggested that habitat patch heterogeneity caused by soil over-wetting and over-nutrient directly affected the habitat selection preference of ground-dwelling arthropods in the island-like swamp forests and had a complex effect on the maintenance of beta diversity.





Response of community composition and lipid metabolism of epilithic biofilms to grazing pressure.

ZHU Feng, WANG Xingzhong, LI Yinke, TAN Xiang

2024, 43(12):  3717-3725.  doi:10.13292/j.1000-4890.202412.028

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Epilithic biofilm is a rich source of polyunsaturated fatty acids (PUFAs) and thus is a high-quality basal food resource in river food webs. Biofilms not only provide food for consumers but are also influenced by consumers. However, our understanding of such feedback is insufficient. To understand the impact of grazing pressure on biofilms, we conducted a 35-day mesocosm experiment under two different conditions, with and without Bellamya aeruginosa, and compared the differences in biofilm using fatty acid and metagenomic sequencing. Under grazing pressure, the proportion of saturated fatty acids (SAFAs) and PUFAs, such as arachidonic acid (ARA), increased by 7.72% and 0.13%, respectively, while the proportion of monounsaturated fatty acids (MUFAs) decreased by 10.14%. Among the microorganisms involved in lipid metabolism, the relative abundance of Proteobacteria and Cyanobacteria decreased, while that of Verrucomicrobia and Actinobacteria increased. At the genus level, the relative abundance of Porphyromonas and Sphingomonas decreased, while Xanthomonas increased. The relative abundance of the fatty acid degradation pathway in biofilm was significantly reduced, while that of the functional gene acetyl-CoA acyltransferase increased significantly in KEGG function prediction. Our findings suggest that biofilm can maintain energy demand and stability by reducing the degradation of fatty acids under grazing pressure.





Methane emission and plant transport capacity of different vegetation types in lake wetlands in the middle reaches of the Yangtze River.

ZHOU Wenchang, XU Xiuhuan, XIANG Shanshan, OU Wenhui, SHI Yuhu, YANG Jiawei, FU Tian, ZUO Yanxia

2024, 43(12):  3726-3734.  doi:10.13292/j.1000-4890.202412.037

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Lakes are an important source of atmospheric methane (CH₄). However, the impacts of plant types and alien plant invasion on CH₄ emissions in lakes are insufficiently investigated. In this study, four sites including open water, floating plant (Trapa natans), emergent plant (Zizania latifolia), and invasive plant (Eichhornia crassipes) regions were selected in the Honghu Lake in the middle reaches of the Yangtze River. The concentration of CH₄ was measured using a floating chamber and gas chromatography method from May to October, 2022. There were temporal variations of CH₄ emission fluxes at the four sites. The CH₄ emission fluxes ranged from 0.10 to 136.12 mg·m^-2·h^-1, with the peak values presenting in summer or autumn. The mean CH₄ emission fluxes were 1.68, 4.52, 4.58, and 28.59 mg·m^-2·h^-1 at the open water, floating plant, emergent plant, and invasive plant sites, respectively. The CH₄ emission fluxes of three sites with plants were 2.7 to 17 times than that of the open water. The CH₄ emission fluxes from the site with invasive plant was 6.2, 6.3, and 17 times that of the emergent plant, floating plant, and open water sites, respectively. These results could be attributed to the massive plant biomass, more effective plant-mediated transport of CH₄, and higher soil organic carbon content in the invasive plant site. The plant-mediated transport of CH₄ at the three sites dominated by Zizania latifolia, Trapa natans, and Eichhornia crassipes were 0.02, 0.23, and 0.25 mg·m^-2·h^-1, respectively, indicating that Eichhornia crassipes was most efficient in CH₄ transport. Our results suggest that CH₄ emission fluxes derived from the invasive plants would be strengthened in the Honghu Lake in the middle reaches of the Yangtze River, which could be a positive feedback on climate change.





Simulation of vegetation productivity in Hebei based on multiple sources of remote sensing data.

XIA Ye, CHEN Jinghua, WANG Shaoqiang, SUN Leigang, CHEN Bin, CHEN Shiliang, WANG Qinyi, ZHAO Ziqi

2024, 43(12):  3735-3745.  doi:10.13292/j.1000-4890.202412.044

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Gross primary productivity (GPP) is a key element of global carbon cycle. Accurate assessment of the spatiotemporal dynamics of GPP in terrestrial ecosystems is essential for global climate change and carbon cycle research. In this study, we simulated and analyzed the spatiotemporal patterns of GPP in Hebei Province from 2003 to 2020 using multi-source satellite remote sensing data of solar-induced chlorophyll fluorescence (SIF), photochemical reflectance index (PRI) and near-infrared reflectance of vegetation (NIRv) and observations from four flux sites in the North China Plain, and compared the differences of results from BEPS, MODIS and GOSIF GPP. The results showed that: (1) The multivariate linear GPP models constructed based on SIF, PRI, and NIRv, can effectively capture the GPP dynamics of flux observations and outperformed the traditional SIF-GPP linear model in grassland, shrubland, and forest (ΔR²=0.02, 0.04, 0.10), but not in cropland; (2) the GPP of terrestrial ecosystems in Hebei Province was 205.63±14.29 Tg C·a^-1 during 2003-2020, with a spatial pattern of low in the northwest and high in the southeast, as well as an overall upward trend with an average annual growth at 2.35 Tg C·a^-1; (3) The simulated GPP of cropland was significantly higher than the results of the other three models, indicating possible underestimations of crop productivity to varying degrees by these models. This study elucidated the potential of multi-source remote sensing data for accurate estimation of vegetation productivity in the North China Plain, and indicated the underestimation of BEPS, MODIS and GOSIF GPP products in croplands, providing directions for further improvement and optimization of GPP products.





Multi-dimensional detection of spatiotemporal variations and driving factors in vegetation carbon sink capacity in Ningxia, China.

HOU Ying, CHU Yang, YANG Qianlong, ZHENG Fang, ZHANG Shuxin, HUANGFU Xiadan

2024, 43(12):  3746-3753.  doi:10.13292/j.1000-4890.202412.002

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The analysis of spatiotemporal variations and driving forces of regional vegetation carbon sink has implications for improving the carbon sequestration capacity of vegetation and contributing to national carbon neutrality. Based on MODIS remote sensing data and soil microbial respiration equations, the spatiotemporal variations and main driving factors of vegetation carbon sink capacity at different spatial scales in Ningxia were explored by using random forest, GeoDetector, and spatial partial correlation analysis. The results would provide scientific basis for ecological protection and high-quality development of the Yellow River Basin in Ningxia. The results showed that the vegetation carbon sink capacity in Ningxia increased overall (with southern part > central part > northern part) but significantly decreased locally in urban centers such as Yinchuan City, Shizuishan City, and Shapotou District in the northern irrigation area from 2000 to 2020. The vegetation carbon sink capacity in Ningxia was mainly influenced by natural factors and the interactions among them, including vegetation, vegetation-climate, and vegetation-elevation, followed by human factors (gross domestic product (GDP) and land use type). The nonlinear enhanced interaction between vegetation normalized index (NDVI) and precipitation was the main driving factor of variations in vegetation carbon sink capacity (84.8%). In terms of different regions, vegetation, population density, vegetation-population density, and vegetation-climate were the main driving forces of vegetation carbon sink capacity in the northern irrigation area, while vegetation, climate, vegetation-climate and vegetation-GDP were the main driving forces in the central arid zone and the southern mountainous area.





Spatial analysis of carbon metabolism in Yulin based on ecological network utility.

HU Anyan, WANG Sibo, HE Yi, LIU Xiuhua, YAN Lin, ZHAO Yingjie

2024, 43(12):  3754-3762.  doi:10.13292/j.1000-4890.202412.003

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Spatial analysis of carbon metabolism is the basis for optimizing urban land use and low-carbon development. In this study, we constructed a horizontal carbon flow model to calculate carbon metabolism density in Yulin City, Shaanxi Province. We employed the approach of ecological network utility to calculate and standardize carbon flux across different land-use types, and obtain the horizontal carbon flow matrix (A). Then, we acquired the effective utilization matrix (D) and overall utility matrix (U), to examine the impact of land use changes on the spatial pattern of unban carbon metabolism and to analyze the spatiotemporal variations of carbon flow in Yulin City. We used a geographic detector model to analyze the driving factors of carbon metabolism and identify the primary drivers for urban carbon metabolism. The results showed that land use change aggravated the disturbance of carbon metabolism in Yulin City from 2000 to 2020, and the net carbon flow was negative in both horizontal and vertical directions. Shenmu City and Yuyang District of Yulin City were the most important negative carbon metabolism compartments. Six counties in the south were positive carbon metabolism compartments. Annual average precipitation and NDVI were the primary drivers of variations of urban carbon metabolism, while annual average temperature and nighttime light exerted relatively minor influence. In conclusion, our results have reference significance for optimizing urban land use and facilitating low-carbon development in semi-arid areas, as well as realizing increasing carbon sink and reducing carbon emissions.





CO₂ exchange and its influencing mechanisms in a reed salt marsh in the Liaohe River estuary during the growing season.

CHENG Hao, XING Qinghui, LIU Siqi, HAN Jianbo, CHEN Hong, ZHANG Chuanqi

2024, 43(12):  3763-3773.  doi:10.13292/j.1000-4890.202412.034

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To investigate the characteristics and influencing mechanisms of ecosystem CO₂ exchange in salt marsh, we monitored net ecosystem CO₂ exchange (NEE) using the eddy covariance technique, and analyzed the effects of photosynthetically active radiation (PAR), temperature (T_a) and biomass on CO₂ exchange in Liaohe River estuary during the growing season. The results showed that the daily average curves of gross primary productivity (GPP), ecosystem respiration (R_eco) and NEE of each month showed inverted ‘U’, horizontal ‘S’ and ‘U’ shape, respectively. There was seasonal variation for CO₂ exchange. GPP and |NEE| reached the maximum cumulative values in June (273.5 and 210.5 g C·m^-2, respectively) and R_eco reached the maximum cumulative value in July (76.7 g C·m^-2). PAR was the dominant factor of NEE in daytime, with a rectangular hyperbola relationship. PAR explained 37.7% to 51.6% variation of NEE. The parameter of light fitting curve reached a maximum in June. T_a and soil water content at 10 cm depth (SWC₁₀) synergistically influenced nighttime respiration (R_eco,night). R_eco,night and T_a showed exponential correlations at different SWC₁₀ levels. When SWC₁₀≤35%, R_eco,night values were derived from early and late growing season, and the temperature sensitivity (Q₁₀) was 1.44. When SWC₁₀>35%, R_eco,night values were derived from middle (Q₁₀=1.97) and vigorous period (Q₁₀=2.03) of the growing season. In the growing season of 2020, the reed salt marsh at the Liaohe River estuary acted as a CO₂ sink, with the NEE, GPP, and R_eco being -693, 1043, and 350 g C·m^-2, respectively.





Research progress on the biogeography of soil fungi.

ZHANG Hanshuo, ZHENG Yong, HE Jizheng

2024, 43(12):  3774-3786.  doi:10.13292/j.1000-4890.202412.041

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Fungi are one of the most diverse biological groups on the Earth. The widespread application of high-throughput sequencing technology over the last decade has greatly improved our understanding of fungal diversity. Fungal biogeography focuses on the geographical distribution pattern and driving factors of fungi at various spatial scales. Generally, soil fungal community does not exhibit a random distribution, while different biotic and/or abiotic factors and inherent characteristics of fungi jointly determine soil fungal community structure. Here, we aim to reveal the diversity and community composition of soil fungi, as well as the key drivers at different spatial scales and relevant biogeographic researches on their ecological functioning. At the global and continental scales, climatic factors and dispersal limitation are the most important factors influencing fungal diversity and distribution patterns. However, niche processes, host plants and soil physicochemical properties have substantial impacts on soil fungal species diversity and community composition at the regional and local scales. Neutral processes are considered to account for the assembly of fungal community at the fine scale. We suggest that future research should address the linkages among fungi, environmental factors, and human activities, the fungal responses to multiple global changes, through large geographic scale samplings covering more habitat or ecosystem types. Hopefully, this mini-review could provide some reference for promoting and improving the theory of soil fungal biogeography.





Research progress of the responses of grassland plants and soil to the variation of temperature and precipitation.

LIU Mingrui, LIU Shiting, MA Chunyan, LI Hui, CHANG Shenghua, HOU Fujiang, LIU Yongjie

2024, 43(12):  3787-3796.  doi:10.13292/j.1000-4890.202412.007

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Under the dual effects of natural and human factors, the frequency of climate change such as extreme events of drought and precipitation increases, grassland vegetation coverage, grassland productivity and soil fertility decrease, and grassland carrying capacity decreases. Understanding the response of grassland ecosystems to climate change is of great significance for the sustainable utilization of grassland resources and the formulation of corresponding ecological protection and restoration measurements. We systematically reviewed the response of grassland ecosystems to the variations of temperature and precipitation from two aspects, grassland vegetation and soil environment, including grassland community structure, plant phenology, grassland productivity, soil temperature and humidity, soil respiration, soil microorganisms and soil enzymes. We focused on the discussions of research scale and experimental methods. On this basis, we put forward some scientific issues that need to be solved urgently in the study of the impact of climate change on grassland ecosystems, such as the cumulative effect and lag effect of plants, the interaction of biological communities, how to improve the accuracy of the model, and the responses of different plant functional groups to extreme climate events, in order to provide reference for future research.





A review on leaf temperature based on oxygen isotope ratios of plants.

HUANG Suimin, WANG Xuming, LI Lei, GONG Xiaoying

2024, 43(12):  3797-3805.  doi:10.13292/j.1000-4890.202412.022

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As a key factor influencing plant productivity and material cycling, leaf temperature is an important parameter in photosynthesis and respiration models and earth system models. Leaf controls temperature by regulating stomata and morphological traits, consequently maintains leaf temperature suitable for photosynthesis and prevents leaf from being damaged by high-temperature stress. Photosynthesis-weighted leaf temperature (T_L-photo) estimated by the fractionation of plant cellulose (Δ¹⁸O_Cel) integrates leaf temperature during photosynthesis. The stability of T_L-photo indicates the effectiveness of plants in leaf thermoregulation, but the relationship between T_L-photo and air temperature remains uncertain. In this review, we discuss the eco-physiological significance and mechanism of leaf thermoregulation, with emphasis on the theoretical basis, model derivation, and uncertainty of measurement methods and results of T_L-photo estimating from Δ¹⁸O_Cel. We put forward that improving the accuracy of Δ¹⁸O_Cel T_L-photo model and its applicability in studying T_L-photo at different scales of leaf-plant-ecosystem should be the main direction of further research.





Invertebrate diversity in peatlands and their responses to environmental change: A review.

LIN Yiling, WU Haitao, LU Kangle, GUAN Qiang, ZHANG Zhongsheng, WANG Wenfeng

2024, 43(12):  3806-3816.  doi:10.13292/j.1000-4890.202412.040

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Peatlands are rich in biodiversity, which are closely associated with environmental factors. The investigation of peatland biodiversity is crucial to comprehending the integrity of peatland ecosystems. Invertebrates are important components of peatland fauna as they are essential participants in nutrient cycling and energy flow. A large number of studies have reported on the distribution, community structure, and response of invertebrates to environmental changes in peatlands. The main taxa of invertebrates in peatlands are nematodes, Collembola, Oribatida, ants, spiders, beetles, and Chironomidae. The research hotspots are Europe, America, China, and Southeast Asia. In this review, we summarized the main taxonomic composition of peatland invertebrates, and the responses of invertebrate communities to environmental changes. We then provided prospects for future research, including: (1) performing a systematic survey of invertebrate fauna in peatlands, and establishing a complete species list; (2) exploring the feedback mechanisms and ecological functions of peatland invertebrates under the background of global climate change; (3) highlighting the role of invertebrates as environmental indicator.





Prediction of carbon sink and contribution to the carbon peaking and carbon neutrality goals of arbor forests in the Yangtze River Delta region of China.

ZHU Nianfu, ZHENG Yeshi, TONG Ran, YUAN Wenwen, LIU Daoping, HONG Yifeng, WU Tonggui

2024, 43(12):  3817-3827.  doi:10.13292/j.1000-4890.202412.006

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Based on the framework of “forest growth + forest logging + forest planting + forest quality improvement”, we forecasted biomass carbon sequestration of arbor forests in the Yangtze River Delta region and their contributions to the carbon peaking and carbon neutrality goals. This study aimed to provide insights into the development of forest management plans and policies related to the carbon peaking and carbon neutrality goals in the Yangtze River Delta region. Drawing from the 9th national forest inventory data (2014-2018), we compiled biomass conversion parameters and carbon content intervals for dominant tree species (groups) through a synthesis of literature. The volume-age regression model for each dominant tree species (groups) in each province of the Yangtze River Delta region was used to predict carbon storage of arbor forests. Carbon sequestration was estimated by assessing the difference in carbon storage between two periods in the Yangtze River Delta region in 2030 and 2060, along with their contribution rates to the carbon peaking and carbon neutrality goals. The results showed that: (1) By 2030, carbon storage of arbor forests in the Yangtze River Delta region is projected to reach 343.46 Tg, with an increase of 141.79 Tg compared to the baseline year. This increase comprises a reduction of 25.88 Tg due to forest logging, an increase of 12.96 Tg from afforestation (growth + quality improvement), and a rise of 55.94 Tg from forest quality improvement (existing arbor forests). The mean annual carbon sequestration is 9.01 Tg·a^-1, equivalent to absorbing 33.04 Tg of CO₂. The contribution rate to carbon peaking in the Yangtze River Delta region by 2030 is projected to be 1.81%. (2) By 2060, carbon storage of arbor forests would reach 573.55 Tg, with a further increase of 230.09 Tg from 2030. This includes a reduction of 13.46 Tg from forest logging, an increase of 25.77 Tg from afforestation (growth + quality improvement), and an augmentation of 72.76 Tg from forest quality improvement (existing arbor forests). The mean annual carbon sequestration is estimated as 7.67 Tg·a^-1, equivalent to absorbing 28.12 Tg of CO₂. The contribution rate to carbon neutrality in the Yangtze River Delta region by 2060 is projected to be 9.53%. In summary, the carbon sink in arbor forests in the Yangtze River Delta region is a stable and efficient pathway for carbon sequestration. By gradually contributing to the achievement of the carbon peaking and carbon neutrality goals, it serves as a valuable forest carbon pool. However, there are challenges such as relatively low overall carbon sequestration, uneven distribution, and untapped carbon sequestration potential. In the future, promoting sustainable forest management practices to facilitate forest regeneration, conducting activities to improve forest quality and enhance carbon sequestration, continuously promoting the afforestation of high carbon-fixing tree species, and transitioning from low carbon density plantations to mixed forests with higher carbon density will be key to enhancing forest carbon sequestration capacity. These efforts will contribute to the realization of the carbon peaking and neutrality goals in the Yangtze River Delta region.





Effluent trading considering ecological water demand guarantee under multi-objective scenarios.

LIANG Ying, LI Jing, LI Yue, WANG Taishan, YOU Li, ZHANG Junlong

2024, 43(12):  3828-3840.  doi:10.13292/j.1000-4890.202412.033

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In this study, elaborate regional characteristic mechanism constraints were constructed to optimize multi-objective oriented effluent trading system considering the ecological water demand guarantee. Following the main line of “simulation-mechanism-strategy”, we examined the effects of ecological water allocation and initial allocation objectives of pollutant discharge permits in Qingdao section of Dagu River Basin, aiming to clarify the optimal strategies of ecological water allocation and initial allocation objectives. The results showed that: (1) The main buyer is livestock and poultry industry in Jiaozhou, while the industrial users are sellers. (2) The total water consumption, pollution loading and system benefit are the highest under objective U (objective of high efficiency), and the lowest under objective L (objective of fairness), with active trading market. (3) With increasing ecological water allocation, water consumption, trading amount and system benefit would decrease. Effluent trading occurs in the dry year and high ecological water allocation scenario, but the system trading amount decreases. (4) Based on the TOPSIS analysis (Technique for Order Preference by Similarity to Ideal Solution), the optimal strategy is obtained, with ecological water allocation being 25% of natural runoff, and the initial allocation objective scenario being fair objective.