Table of Content

18 April 2025, Volume 36 Issue 4

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Special Features of the Soil Ecology and Healthy Agriculture

Effects of organic inputs on soil nutrients and microbial metabolism in newly reclaimed farmlands

YIN Qijie, JIANG Jianwu, YIN Hanqin, YANG Zongkun, GONG Dongqin, LI Guifang, CHU Xianyao, LIU Wenbo, ZHANG Min

2025, 36(4):  969-983.  doi:10.13287/j.1001-9332.202504.007

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It remains unclear how soil microbial metabolism responds to organic input and the driving factors during soil carbon fixation and fertilization in newly reclaimed farmlands. We conducted a field experiment to explore the effects of different organic inputs on soil nutrients, organic carbon fractions, extracellular enzyme activities, microbial metabolism, and microbial carbon utilization efficiency in a newly reclaimed farmland with a rice-wheat rotation in Jiande of Zhejiang in 2022. Five treatments were implemented with equivalent C return in addition to conventional chemical fertilizers (NPK): 1) NPK alone (control), 2) NPK + manure + maize straw (MS), 3) NPK + manure (M), 4) NPK + straw biochar-based manure (MBF), and 5) NPK + straw biochar (MB). The results showed that organic inputs significantly enhanced soil nutrients, soil organic carbon fractions, and microbial activity compared to NPK. In terms of soil nutrient improvements, the order was M > MBF > MS > MB, while crop yield followed the order of MS > M > MBF > MB. The active organic carbon contents followed the order of M > MS > MBF > MB, with a 91.7% increase in the M treatment compared with NPK. For recalcitrant organic carbon contents, the sequence was MB > MBF > M > MS, with a 160.7% enhancement in the MB treatment than NPK. The microbial biomass showed the order of M > MS > MBF > MB. Microbial biomass carbon, nitrogen, and phosphorus in the M treatment was increased by 81.1%, 140.9%, and 261.1%, respectively compared with NPK. Extracellular enzyme activities followed the order of MS > M > MB > MBF. The MS treatment increased C cycle-related enzyme activities (β-glucosidase, β-xylosidase, and β-cellobiohydrolase) by 176.3%, 180.4%, and 439.2%, respectively, and N cycle-related enzyme activity (N-acetyl-β-glucosaminidase) by 331.4% compared with NPK. Results of Mantel correlation analysis and redundancy analysis showed that dissolved organic carbon and microbial biomass carbon were the primary drivers of extracellular enzyme activities during the wheat and rice growing seasons. Enzyme vector models and partial least squares path modeling revealed that soil microbial metabolism in the newly reclaimed farmland was constrained by both carbon and phosphorus contents. Organic inputs alleviated phosphorus limitation by improving soil nutrient availability and decreased microbial carbon use efficiency by increasing active organic carbon content. In summary, organic inputs played a positive role in soil carbon fixation and fertilization in the newly reclaimed farmland. Among the treatments, MBF showed the best comprehensive effect on soil carbon fixation and fertilization.

Effects of potassium and trace elements on soil ecological functions and health status in Loess Plateau dryland farmland

GUO Huan, LI Chunyue, KOU Zhaoyang, GAO Chuanyu, ZHANG Le, LI Yifan, DANG Tinghui

2025, 36(4):  984-994.  doi:10.13287/j.1001-9332.202504.017

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Understanding the effects of potassium and trace element application on soil ecological functions and soil health in farmland can provide theoretical basis for soil nutrition management. In this study, we examined the impacts of potassium and trace element addition on soil ecological function and health in farmland with long-term application of nitrogen and phosphorus fertilizer in Changwu Agricultural Ecological Experimental Station, Chinese Academy of Sciences. There were six treatments, a control without potassium and trace elements (CK), K addition (30 kg·hm^-2 of potassium chloride), Cu addition (15 kg·hm^-2 of copper sulfate), B addition (11.25 kg·hm^-2 of borax), Mn addition (22.5 kg·hm^-2 of manganese sulfate), and Zn addition (15 kg·hm^-2 of zinc sulfate). We collected soil samples of 0-20 cm layer to analyze the soil physical and chemical properties and microbial acti-vity indicators, constructed the minimum data set and calculated the soil health index. The results showed that K addition significantly increased soil available phosphorus content by 27.2%, increased alkaline phosphatase activity by 52.2%, and improved the bioavailability of soil phosphorus. The addition of Cu significantly increased soil respiration by 40.8% and N-acetylglucosamine enzyme activity by 63.6%, enhancing soil carbon and nitrogen conversion. The content of total phospholipid fatty acids, bacterial phospholipid fatty acids, and anaerobic phospholipid fatty acids was increased by 8.5%, 7.2%, and 12.3%, respectively, and microbial biomass carbon and nitrogen contents were promoted. The addition of Zn and B significantly reduced the biomass of bacteria, arbuscular mycorrhizal fungi, Gram positive bacteria, Gram negative bacteria, and actinomycetes by 35.3%, 32.2%, 31.5%, 40.1%, 34.5%, and 22.6%, 26.4%, 20.5%, 23.9%, and 22.6%, respectively, and reduced soil respiration. The addition of Mn significantly increased soil β -1,4-glucosidase activity (45.6%), but reduced the biomass of bacteria, arbuscular mycorrhizal fungi, Gram positive bacteria, Gram negative bacteria, actinomycetes, and soil respiration. The soil health index of each treatment was as follows: K(0.94)>Cu(0.80)>CK(0.78)>B(0.75)=Mn(0.75)>Zn(0.71). In summary, K and Cu addition to farmland soil in the Loess Plateau would be beneficial for the health and stability of soil ecosystems.

Effects of the photovoltaic-earthworm model and organic material application on soil quality

XIAO Yuanye, ZHANG Shoutao, ZHANG Menghao, ZHONG Hesen, XU Weiqing, LI Xinyu, MAO Runqian, ZHANG Chi

2025, 36(4):  995-1002.  doi:10.13287/j.1001-9332.202504.030

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We investigated the effects of earthworm and organic material application methods on soil quality on slopes where photovoltaic panels are installed, aiming to explore a new model for promoting sustainable development of photovoltaic agriculture and improving soil quality. We proposed the photovoltaic-earthworm model, which involves breeding Amynthas aspergillum with high medicinal value in the soil under photovoltaic panels. There were four treatments: surface application of cow manure between photovoltaic panels to breed earthworms (Out+S), surface application of cow manure under photovoltaic panels to breed earthworms (In+S), mixed application of cow manure between photovoltaic panels to breed earthworms (Out+M), and mixed application of cow manure under photovoltaic panels to breed earthworms (In+M), with the bare land as the control (CK). We measured soil physical and chemical properties, as well as the enzyme activities. The results showed that the content of soil mechanical stability and water stability macroaggregates, organic carbon, total nitrogen, alkaline nitrogen, available phospho-rus, available potassium, and acid phosphatase activity, were significantly enhanced in Out+M and In+M treatments compared to CK by 4.7%-18.7%, 6.2%-26.0%, 37.5%-113.9%, 39.4%-90.9%, 43.4%-196.8%, 222.9%-762.5%, 246.1%-460.7% and 25.3%-33.3%, respectively. The content of soil mechanical stability and water stability macroaggregates under photovoltaic panels (In) was increased by 13.4%-21.5% and 16.1%-16.2%, respectively, compared to between photovoltaic panels (Out). The soil alkaline nitrogen content, carbon nitrogen ratio, and acid phosphatase activity was increased by 18.5%-34.1%, 13.8%-16.8%, and 6.3%-36.5%, respectively. The content of soil mechanically stable macroaggregates, water stable macroaggregates, and water stable macroaggregates with particle size ≥0.25 mm in mixed application of cow manure (M) treatments was increased by 6.6%-14.3%, 18.5%-18.6%, and 3.2%-3.8%, respectively, compared to the surface application of cow manure treatment (S). The content of organic carbon, total nitrogen, alkaline hydrolyzed nitrogen, available phosphorus, carbon nitrogen ratio, and acid phosphatase activity was increased by 55.5%-88.2%, 37.0%-60.5%, 54.4%-74.6%, 102.4%-117.8%, 13.4%-16.4%, and 30.7%-67.7%, respectively. The destruction rate of soil aggregates decreased by 39.0%-50.9%. Soil macroaggregates were significantly positively correlated with organic carbon, soil nutrients, and acid phosphatase. Soil quality of each treatment followed an order of In+M>Out+M>In+S>Out+S>CK. In summary, In+M has the great potential for promoting local economic development, protecting the ecological environment, and improving soil quality in the development of slope photovoltaic agriculture in southern China.

Effects of adding basalt powder on organic carbon sequestration in red and yellow-brown soils under earthworm inoculation

TENG Yalin, LI Weiming, WANG Dongsheng, LIANG Xihuan, CHEN Jin, YE Chenglong, LIU Manqiang, HU Shuijin

2025, 36(4):  1003-1012.  doi:10.13287/j.1001-9332.202504.020

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The enhanced weathering technology of basalt can promote the fixation of atmospheric carbon dioxide in the form of carbonates/bicarbonates in soils. Earthworms can promote mineral weathering, further contributing to carbon fixation. In this study, we selected red and yellow-brown soil as research subjects and set up three treatments [i.e., control (CK), adding basalt powder (B), and adding basalt powder and inoculating earthworms simu-ltaneously (BE)], and explored the impact and potential mechanisms of earthworm-mediated basalt weathering on Amaranthus tricolor growth, soil respiration, microbial abundance, Ca² and Mg²⁺, soil total organic C, inorganic C and mineral-bound organic C in the field. The results showed that B and BE treatments significantly increased soil pH and Mg²⁺ content of both soils, but significantly increased Ca²⁺ content, soil respiration, aboveground and belowground biomass of A. tricolor only in the red soil. B and BE treatments significantly reduced reactive Fe and Al minerals in both soils and NH₄⁺-N content of the yellow-brown soil, but did not affect NO₃^--N content of both soils. BE treatment significantly increased bacterial abundance of the red soil, but did not affect fungal abundance of both soils. BE treatment significantly increased inorganic C content only in the yellow-brown soil, but significantly reduced Fe/Al bound organic C of the yellow-brown soil, and had no significant effect on total C and organic C of both soils. In addition, BE treatment had no significant effect on soil organic C, inorganic C and Fe/Al bound organic C of both soils compared with B treatment. The random forest model analysis revealed that fungal abundance is the key factor regulating organic carbon accumulation in red soils, while active aluminum minerals and iron-aluminum minerals are respectively identified as the critical determinants controlling the accumulation of organic carbon and iron-aluminum bound organic carbon in yellow-brown soils. Our results indicate that adding basalt powder to soil can significantly promote plant growth in the short term, but did not affect soil organic C formation. The role of earthworms in promoting basalt weathering and soil organic C sequestration in the short term is limited.

Effects of water-saving irrigation on seedling growth, stomatal characteristics and photosynthetic properties of maize in secondary salinized cultivated land

WANG Fuqin, YUE Jianmin, HE Wenwen, LI Yulong, LI Yang, MA Guojun

2025, 36(4):  1013-1023.  doi:10.13287/j.1001-9332.202504.011

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To clarify the alleviating effect of different water-saving irrigations at the seedling stage of maize under salt stress in arid irrigation area, we used ‘Xianyu 1225' maize as the test material, and set up three irrigation treatments (T1, T2, and T3) in the salinized land in the Yellow River irrigation area. T1 treatment was the surface furrow irrigation at the sowing stage and three-leaf stage (T1, irrigation amount was 65 mm at both stages). Both T2 and T3 treatments were furrow irrigation at the sowing stage and drip irrigation at three-leaf stage (the irrigation amount at the sowing stage was 65 mm, and the irrigation amount at the three-leaf stage was 39 and 52 mm, respectively). The control (CK) was furrow irrigation at the sowing stage and the three-leaf stage in non-salinized land (irrigation amount was 65 mm at both stages). We investigated the effects of water-saving irrigation on leaf morphology, photosynthetic physiology, photosynthetic tissue structure and leaf fluorescence characteristics of maize seedlings under salinity stress. The results showed that furrow irrigation combined with drip irrigation could effectively reduced soil salt content and weakened soil salinity returning to the 0-20 cm soil layer of salinized land. Compared with CK, different irrigation treatments significantly changed the morphology, reduced antioxidant enzyme activities, stomatal structure, photosynthetic pigment content, photosynthetic fluorescence performance of maize leaves under salinity stress. Such decreases were the largest under the T1 treatment, and were relieved under T2 and T3 treatments. Furthermore, T3 treatment differed little in the antioxidant enzyme activities, net photosynthetic rate, transpiration rate, effective photochemical efficiency of maize leaves compared to CK. According to the results of structural equation model analysis, the water-saving irrigation increased the maximum photochemical efficiency of maize and alleviated the inhibition of salt stress on maize growth at seedling stage by reducing the Na⁺ content of plants, protecting the photosynthetic tissue and adjusting the proportion of photosynthetic pigments. In conclusion, the T3 mode was the best irrigation strategy in the study area.

Original Articles

Characteristics of soil organic carbon components across a chronosequence of Cryptomeria japonica plantations in Rainy Area of Western China

WANG Yuehan, WANG Rui, LI Yu, YOU Chengming, XU Lin, XU Hongwei, TAN Bo, XU Zhenfeng

2025, 36(4):  1024-1034.  doi:10.13287/j.1001-9332.202504.013

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Soil organic carbon (SOC) components are crucial indicators of soil fertility and carbon sequestration capacity, playing a pivotal role in maintaining global carbon balance. However, the dynamics of SOC components across plantations with different stand ages remain poorly understood. In this study, we collected soil samples (0-15 cm and 15-30 cm) from 7, 13, 24, 33 and 53 years stands of Cryptomeria japonica plantations in the Rainy Area of Western China to quantify the contents of different SOC components, including particulate organic carbon (POC), easily oxidized organic carbon (EOC), light fraction organic carbon (LFOC), heavy fraction organic carbon (HFOC), labile organic carbon (LOC), and inert organic carbon (IOC). The results showed that: 1) POC content increased continuously with stand age, while contents of LOC, EOC, LFOC, HFOC, and IOC followed unimodal patterns, peaking at 24- and 33-year-old stands. 2) All SOC components were significantly higher in surface layer (0-15 cm) than subsurface layer (15-30 cm). The differences in POC and LFOC between two soil layers increased with stand ages, while EOC and LOC exhibited maximal inter-layer differences at 24 and 33 years, respectively. 3) Results of variance partitioning analysis showed that microbial variables (fungal and bacterial biomass, and enzyme activities) exerted stronger explanatory power on POC variation than soil physicochemical pro-perties. Other SOC components were co-regulated by both biological and physiochemical factors. Partial least squares path modeling further demonstrated that stand age directly influenced POC and indirectly modulated all SOC components by mediating soil physicochemical and microbial characteristics. In all, our findings suggested that there were distinct age-dependent patterns in SOC components in C. japonica plantation and their vertical stratification were driven by stand age-associated changes in soil microbial and physiochemical properties. This study would be helpful for understanding soil carbon sequestration along plantation development, and could offer scientific basis for enhancing carbon sink functions in C. japonica plantation.

Effects of stand density on understory vegetation and soil properties in Populus simonii plantations

HUANG Xian, YU Xinxiao, JIA Guodong, CHANG Xiaomin, SUN Libo

2025, 36(4):  1035-1042.  doi:10.13287/j.1001-9332.202504.001

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We investigated the understory vegetation, determined the physicochemical properties at 0-20 and 20-40 cm soil layers in 28-year-old Populus simonii plantations under different stand densities (450, 600, 750, 950, 1100 trees·hm^-2) in Zhangbei County, Zhangjiakou City, Hebei Province, aiming to understand the effects of stand density on species diversity of understory plants and soil physicochemical properties. The results showed that there were almost no shrubs in the understory. A total of 38 species, 30 genera, 18 families of herbaceous plants were observed in the understory vegetation. The dominate herbaceous plants were from the Cyperaceae, Fabaceae, Gramineae, Brassicaceae, and Compositae. When the stand density of P. simonii increased, Margalef richness index (D_M), Simpson dominance index (D_S), Shannon diversity index (H), and Pielou evenness index (E) of the herbaceous plant communities rose first but then declined, and peaked at the stand density of 600 trees·hm^-2. The overall trend of soil nutrients in the two soil layers increased first and then decreased with increasing stand density, and the maximum value all appeared at 600 trees·hm^-2. The contents of soil total nitrogen, total phosphorus, alkali-hydrolyzable nitrogen, available phosphorus, and available potassium positively correlated with understory herbaceous species diversity index. In the 0-20 cm soil layer, soil total nitrogen and available phosphorus contents were significantly positively correlated with D_M, D_S, H and E. Soil total phosphorus content had significant positive correlation with D_S and H. There was a significant positive correlation between alkali-hydrolyzable nitrogen and D_S. In the 20-40 cm soil layer, soil bulk density had a significant negative correlation with D_M, D_S, H, and E. Soil total phosphorus content had a significant positive correlation with D_M, D_S, H, and E. There was a significant positive correlation between soil available potassium and D_M and H. The stand density of 600 trees·hm^-2 was the optimal one for P. simonii plantations in this region, which could improve understory herbaceous species diversity, provide good growth space for understory vegetation, and enhance soil fertility.

Stem radial growth of dominant subalpine coniferous species and their responses to moisture variability in Northwest Yunnan, China

ZHANG Yixue, FAN Zexin, FU Peili, ZHANG Hui, Dujie Citan, HE Zhenghua

2025, 36(4):  1043-1052.  doi:10.13287/j.1001-9332.202504.034

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The Hengduan Mountains region is sensitive to climate change. Although many dendrochronological studies have been conducted in this region, few researches examined seasonal variations of stem radial growth and their responses to environmental factors of subalpine coniferous tree species. We monitored stem radial variations of four dominant coniferous species i.e. Abies georgei, Larix potaninii, Picea brachytyla var. complanata, and Pinus densata, in Shangri-La National Park, using high-resolution dendrometers. We analyzed the diurnal patterns of stem growth and their responses to the variations of atmospheric and soil moisture in 2022 and 2023. The results showed that: 1) stem radial growth of the four tree species mainly occurred at night, with the species that reached peak growth earlier at night, such as A. georgei, showing greater radial growth and more growth hours. 2) Stem radial growths of the four tree species were negatively correlated with vapor pressure deficit (VPD) and soil water content (SWC). 3) Stem radial growths of A. georgei and L. potaninii at higher altitudes were more sensitive to changes in VPD. However, stem radial growths of P. brachytyla var. complanate and P. densata at lower elevations were more influenced by soil water content. By revealing differential responses of subalpine conifer species at a diurnal scale and the main environmental limiting factors, our results would provide new insights into understanding how subalpine coniferous trees respond to climate change in the Hengduan Mountains.

Construction of biomass models for understory shrubs and tree saplings in Fenglin County, Heilongjiang Province, China.

LI Zelin, JIA Weiwei, ZHAO Yang, JIANG Shan

2025, 36(4):  1053-1061.  doi:10.13287/j.1001-9332.202504.004

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Shrubs and tree saplings are important components of understory in natural forests, possessing rich species diversity and broad ecological adaptability. They play a key role in soil moisture retention, water conservation, and wind and sand prevention. However, current research has mostly focused on the interactions between the tree layer and understory, with less attention on the growth dynamics, biomass renewal, and environmental adaptability of understory. Based on data of 18 shrub species and sapling of six tree species from the understory of Fenglin County in Heilongjiang Province, along with climate data from the sampling sites, we introduced two dummy variables, stand density and age class, to construct a biomass model for understory shrubs and tree saplings. The results showed that incorporating climate factors (mean annual temperature and mean annual precipitation) into the base model to construct a climate-sensitive biomass model significantly improved the model's fitting accuracy. The coefficient of determination (R²) increased from 0.732 in the base model to 0.741, with an improvement of 6.8%. Based on the climate-sensitive biomass model, single dummy variables for age class and a dual dummy variable model combining stand density and age class were introduced. The dual dummy variable model showed the best fit, with an R² of 0.840, being significantly higher than the single dummy variable model (R²=0.787) and the climate-sensitive biomass model (R²=0.741). The model constructed based on the climate-sensitive biomass model and incorporating dual dummy variables for stand density and age class, could effectively reflect the biomass variations of shrubs and tree saplings under different age classes and stand densities. It would provide a basis for forest ecological management and the scientific estimation of biomass, with significant practical value.

Responses of leaf nutrient resorption in marsh plants to shrub encroachment in Sanjiang Plain, China

YANG Jing, XUE Jing, YIN Ziliang, FENG Weihui, ZHAO Wanjing, ZHANG Li, WANG Qingbo, SUN Xiaoxin

2025, 36(4):  1062-1070.  doi:10.13287/j.1001-9332.202504.002

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Based on the coverage of the shrub Spiraea salicifolia (0-100%) in the Sanjiang Plain, we examined the responses of nitrogen (N), phosphorus (P), and potassium (K) content, as well as nutrient resorption efficiency in the mature and senescent leaves of three dominant marsh plants (Deyeuxia purpurea, Carex schmidtii, and S. salicifolia) to four degrees of shrub encroachment: no shrub encroachment, light shrub encroachment (0-30%), moderate shrub encroachment (30%-70%), and heavy shrub encroachment (>70%). The results showed that shrub encroachment did not significantly affect N, P, and K contents in the mature leaves of the marsh plants. It significantly reduced K content in the senescent leaves of D. purpurea and S. salicifolia by 40.1% and 60.6%, respectively, and the N content in the senescent leaves of C. schmidtii by 25.3%. Nutrient resorption efficiency of marsh plants responded differently to shrub encroachment. After shrub encroachment, N, P, and K resorption efficiencies (NRE, PRE, KRE) of D. purpurea were significantly increased by 14.6%, 9.5%, and 3.2%, respectively. The NRE of C. schmidtii increased significantly by 12.6%, but KRE decreased significantly. For S. salicifolia, KRE increased significantly by 14.8%, while there were no significant changes in the NRE and PRE. C. schmidtii disappeared under the heavy shrub encroachment plots, whereas D. purpurea persisted. Redundancy analysis indicated that N, P, and K contents and N:P:K stoichiometric ratio of leaves were the main factors influencing nutrient resorption efficiency. Both D. purpurea and C. schmidtii adapted to shrub encroachment by adjusting leaf nutrient resorption. With the flexible nutrient allocation strategy, D. purpurea was better suited to nutrient-poor environment, forming a complementary nutrient utilization strategy with the encroachment of S. salicifolia.

Long-term effects of forest fires on soil physicochemical properties, enzyme activities, and microbial communities in the broad-leaved Korean pine forest of the Xiaoxing'an Mountains, Northeast China

CHE Jiacong, YANG Jia, WU Zhenghong, GU Huiyan

2025, 36(4):  1071-1080.  doi:10.13287/j.1001-9332.202504.014

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The broad-leaved Korean pine forest in the Xiaoxing'an Mountains is representative of temperate mixed coniferous and broad-leaved forests. In this study, we selected burned area of broad-leaved Korean pine forest and the adjacent unburned area (control) to investigate soil physicochemical properties, enzyme activities, and microbial characteristics after 28 years natural recovery. We further analyzed the main soil factors influencing enzyme activities and microbial communities. The results showed that: 1) soil total nitrogen, alkali-hydrolyzable nitrogen, and water content in the burned area were significantly lower than the control by 28.0%, 39.3% and 4.5%, respectively. However, the activities of catalase, restriction endonuclease, urease, nitrate reductase, and soil dehydrogenase were significantly increased. 2) The α- and β-diversity of soil bacterial and fungal communities in the burned area was not different from those of the control after 28 years recovery, but marked differences were observed in community composition at phylum and genus levels. 3) Redundancy analysis and structural equation modeling revealed that soil pH was the primary factor influencing enzyme activities and microbial communities. 4) After 28 years, the stability and complexity of soil bacterial network in the burned area increased, while the fungal network showed an opposite trend. These results suggested that forest fires have long-term effects on soils, with soil physicochemical properties, enzyme activities, and microbial communities exhibiting distinct post-fire recovery patterns.

Ecological stoichiometric imbalance drives the responses of soil bacterial communities to nitrogen addition in an alpine meadow

LIAN Chenxing, ZHANG Qiufang, REN Fei, LI Lanping, CHEN Jingqi, ZENG Quanxin, CHEN Yuemin, ZHU Biao

2025, 36(4):  1081-1090.  doi:10.13287/j.1001-9332.202504.018

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Nitrogen is the main limiting nutrient for the productivity of grassland ecosystems, and can indirectly affect the structure of microbial communities, especially bacterial communities, by altering soil properties. In this study, we conducted a field nitrogen addition experiment in the alpine meadow of Haibei in the northeastern Tibetan Plateau. Urea was used as the nitrogen source. Five nitrogen addition levels were set up: N₀ (control, no nitrogen addition), N₅₀ (50 kg N·hm^-2·a^-1), N₁₀₀ (100 kg N·hm^-2·a^-1), N₁₅₀ (150 kg N·hm^-2·a^-1), and N₂₀₀ (200 kg N·hm^-2·a^-1). In the third year of the experiment, we collected soil samples of the surface layer to measure soil physical and chemical properties, stable isotope δ¹⁵N, and microbial biomass. The microbial stoichiometric imbalance was calculated, and bacterial community characteristics (composition, diversity, and community assembly) along the nitrogen addition levels were analyzed by 16S rRNA high-throughput sequencing. Through correlation analysis, non-metric multidimensional scaling analyses, and phylogenetic-bin-based null model analyses, we investigated the driving mechanisms of the changes in soil bacterial community composition and community assembly. The results showed that: 1) Nitrogen addition significantly altered soil bacterial community composition, but did not change the α diversity of soil bacteria. 2) Nitrogen addition significantly increased soil inorganic nitrogen content by 85.7% and reduced the stoichiometric imbalance of carbon:nitrogen by 40.6%. Soil inorganic nitrogen content and carbon:nitrogen stoichiometric imbalance were significantly correlated with bacterial community composition and the relative abundance of the dominant phylum (i.e., Bacteroidetes), indicating that bacterial taxa were significantly influenced by soil available nitrogen and stoichiometric imbalance. 3) The stochastic process (54.7%-56.8%) dominated the community assembly of soil bacteria across all treatments. Nitrogen addition had no significant effect on the community assembly of soil bacteria. In conclusion, soil available nitrogen and the resulting stoichiometric imbalance were the primary factors regulating the relative abundance of bacterial taxa under nitrogen addition. Our findings provide a scientific basis for predicting the changes of soil microbial communities in alpine meadows in the context of future environmental changes.

Effects of shrub-grass vegetation and biocrusts on soil and water loss and hydrodynamic characteristics of Loess Plateau slopes under rainstorm conditions

DAN Chenxi, ZHANG Qiong, LIU Gang, XIA Xiaolin

2025, 36(4):  1091-1098.  doi:10.13287/j.1001-9332.202504.009

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During the initial stages of vegetation restoration on the Loess Plateau, shrub-grass vegetation effectively mitigates soil erosion caused by intense rainfall, while biological soil crusts (biocrust) and vegetation collectively can regulate runoff and sediment yield processes. However, their combined effects are usually overlooked. To quantify the impacts of shrub-grass vegetation and biocrust on runoff-sediment dynamics and to elucidate their synergistic effects on erosion mechanics, we conducted indoor artificial simulations of short-duration, high-intensity rainfall events, with nine treatments: bare soil (CK, no vegetation/biocrust); grassland; shrub; biocrust with 20% coverage; grassland+biocrust with 20% coverage; shrub+biocrust with 20% coverage; biocrust with 40% coverage; grassland + biocrust with 40% coverage; and shrub + biocrust with 40% coverage. The results showed that: 1) During the rainfall events, CK consistently exhibited the highest sediment volume, while the shrub, grass, and biocrust significantly reduced erosion. 2) Compared to the CK, shrub and grass reduced runoff by 21.9% and 18.2%, respectively, which promoted soil moisture infiltration. In contrast, biocrust with 20% and 40% coverage increased runoff by 9.5% and 17.4%, respectively, indicating that biocrusts inhibited infiltration. The positive effect of vegetation on soil infiltration surpassed the negative impact of biocrusts under vegetation+biocrust conditions. 3) The grassland+biocrust with 20% coverage treatment and all treatments with 40% biocrust generated subcritical flow, while other treatments were supercritical flow. All treatments showed lower average flow velocity and flow kinetic energy than CK, but exhibited higher flow shear stress and resistance coefficients. Compared to the CK, the grassland+biocrust with 40% coverage treatment demonstrated the highest runoff shear stress and resistance coefficient, with 164.5% and 213.8% increases, respectively, while the runoff kinetic energy was the lowest, decreasing by 91.9%. These findings suggested that maintaining appropriate biocrust coverage during the early stages of vegetation recovery could be helpful for enhancing soil conservation and ecosystem stability. Under the experimental conditions, the grassland+biocrust with 40% coverage treatment is optimal for soil erosion reduction.

Aluminum absorption capacity of different cultivars of Hydrangea macrophylla seedlings under aluminum stress and the physiological and biochemical mechanisms

CHEN Wenjuan, CHEN Shuangshuang, FENG Jing, CHEN Huijie, ZHOU Huimin, LIU Xintong, ZHANG Xuhui, DENG Yanming

2025, 36(4):  1099-1108.  doi:10.13287/j.1001-9332.202504.019

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Hydrangea macrophylla exhibits strong tolerance to acid and aluminum stress. Many cultivars can absorb Al³⁺ from soils, resulting in variations of their flower color from red to blue. This characteristic presents a potential avenue for the ecological remediation of aluminum-rich acidic soils. To assess the capacities of aluminum absorption among different cultivars, we utilized the cutting seedlings of 45 popular H. macrophylla cultivars via hydroponic culture, which were treated under 0 (control) and 800 μmol·L^-1 Al₂(SO₄)₃. The aluminum absorption abilities were determined through root tip staining and aluminum content determination methods. We selected two representative cultivars with the strongest or weakest aluminum absorption capacities for further investigation of the physiological and biochemical mechanisms under aluminum stress. The results showed that the 45 cultivars could be categorized into five levels according to their aluminum absorption capacities: strong, relatively strong, intermediate, relatively weak, and weak, comprising 2, 11, 15, 15, and 2 cultivars, respectively. Amongst them, Bailer and White angel were identified as representative of strong and weak aluminum absorption capacities, respectively. In comparison to White angel, the aluminum-treated Bailer exhibited significant increases in chlorophyll content, transpiration rate, net photosynthetic rate, intercellular CO₂ concentration, and stomatal conductance with significant increase of 24.8%, 63.9%, 11.2%, 9.2%, and 66.7%, root length, root surface area, root volume, and root tip number increased by 4.7%, 2.9%, 14.3%, and 7.8%, the activities of antioxidant enzymes (peroxidase, catalase, and superoxide dismutase), and the contents of soluble sugar and soluble proteins exhibited significant increases by 88.4%, 35.3%, 7.7%, 2.4%, and 21.7% in the roots, and 78.4%, 103.7%, 101.1%, 138.9%, and 18.1% in the leaves, respectively. These findings suggested that Bailer could effectively mitigate damage from Al stress by enhancing photosynthesis, antioxidant enzymatic activities, and nonenzymatic antioxidants, thereby improving its aluminum absorption ability and tolerance, which has the potential application in the remediation of aluminum-rich acidic soils.

Effects of nitrogen addition on Arachis hypogaea “Qicai”-rhizobia symbiosis and biomass allocation

LI Lin, SUN Yi, YANG Xiaoqiong, FANG Haidong, SHI Liangtao, HE Guangxiong, YU Jianlin, YAN Bangguo

2025, 36(4):  1109-1117.  doi:10.13287/j.1001-9332.202504.010

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To reveal how rhizobia affects biomass allocation of peanuts under different nitrogen concentrations, we conducted a pot experiment by treatments of Arachis hypogaea “Qicai” with and without Bradyrhizobium inoculation to investigate the characteristics of plant biomass allocation and symbiotic nodulation at the nitrogen addition level of 0, 8, 16, 32, 64 and 128 mmol·L^-1. The results showed that: 1) Under non-inoculation, the addition of low-level nitrogen (8-32 mmol·L^-1) had limited impact on plant biomass. When nitrogen addition level reached 64 mmol·L^-1, total plant biomass, leaf biomass, leaf area, and total net photosynthetic rate increased significantly by 82.1%, 116.6%, 116.1% and 122.1% respectively in compared with those without nitrogen addition (0 mmol·L^-1). 2) Under the condition of inoculation, total plant biomass, leaf biomass, leaf area, and total net photosynthetic rate increased under the nitrogen addition level of 16 mmol·L^-1 by 65.3%, 97.5%, 91.7%, and 112.8%. The nodulation amount of plants and the total amount of leghemoglobin first increased and then decreased with the increases of nitrogen addition level, reaching their maximum values at 49.00 mg·plant^-1 and 0.12 mg·plant^-1 respectively at the nitrogen addition level of 16 mmol·L^-1. When the nitrogen addition level reached 64 mmol·L^-1, they decreased significantly. There was no nodulation of roots when the nitrogen addition was 128 mmol·L^-1. 3) Rhizobia inoculation significantly increased leaf biomass, aboveground biomass, leaf area, and total net photosynthetic rate when nitrogen addition level ranged from 8 to 64 mmol·L^-1, with an overall increase of 43.3%, 37.6%, 34.5%, and 53.8% respectively. However, rhizobia inoculation did not affect those indices when the nitrogen addition level was 0 or 128 mmol·L^-1. Overall, rhizobia inoculation significantly increased the allometric growth constants of leaf-root and leaf-total biomass, and decreased the allometric growth constants of root-stem and root-total biomass. In conclusion, peanuts actively adjust resource allocations among different organs with a trade-off between environmental nitrogen absorption and symbiotic nitrogen fixation, which would maximize the benefit of resource investments. Among the N addition levels involved in this study, 16 mmol·L^-1 is optimal for the symbiotic nodulation of A. hypogaea “Qicai” and Bradyrhizobium.

Predicting suitable habitats of high-yield and -quality Lycium barbarum based on climate characteristics in production area of Qinghai, China

SONG Zhongkang, LIU Zhongxu, DENG Changrong, DUAN Guozhen, FAN Guanghui, LI Jianling

2025, 36(4):  1118-1126.  doi:10.13287/j.1001-9332.202504.025

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The unique climatic conditions of Qinghai are highly suitable for the growth of goji berry (Lycium barbarum), with superior yield and quality to other production areas. Screening areas with similar conditions can guide the scientific cultivation of high-yield and high-quality goji berry, thereby increasing income. Based on the climatic characteristics of Qinghai production area, we utilized the optimized MaxEnt model and ArcGIS to identify the key meteorological factors affecting the distribution of suitable habitats and to predict suitable distribution areas under different climate scenarios. The results showed that the optimized feature combination was linear and quadratic, and the regularization multiplier was 0.5, with both the area under the receiver operating characteristic curve of the subject and true skill statistic values being greater than 0.90, indicating highly accurate and reliable prediction. The key meteorological factors affecting the distribution of high-yield and high-quality goji berry were mean diurnal temperature range (suitable range was 12.94-19.08 ℃) and maximum temperature of warmest month (19.01-28.32 ℃). Under current climatic conditions, the area of suitable habitat for high-yield and high-quality goji berry in China was 42.69×10⁴ km², primarily distributed in the Qaidam Basin of Qinghai, the northwest and the foothills of the Qilian Mountains of Gansu, the foothills of Kunlun Mountains and Altai Mountains in Xinjiang, and the central-western part of Xizang. In the future climate scenarios (2050s and 2070s), the area of suitable habitat for high-yield and high-quality goji berry was larger than the current ones, showing an eastward expansion trend. The area of suitable habitats reached its maximum under the SSP585 (59.26×10⁴ km²) and SSP370 scenarios (58.51×10⁴ km²), respectively. Temperature was the key meteorological factor influencing the distribution of high-yield and high-quality goji berry. Climate warming would cause the expansion of suitable habitat eastward, benefiting its cultivation.

Effects of different tree forms and grass mulching on microclimate in Ziziphus jujuba orchards in the plain regions of southern Xinjiang, China

SHI Ranqi, WANG Hansheng, DENG Wenkai, ZHANG Xia, LIU Yuping, HUANG Jian, HAN Gang

2025, 36(4):  1127-1134.  doi:10.13287/j.1001-9332.202504.015

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Tree form training and inter-row grass mulching are important components of modern orchard management. To explore optimal cultivation and management measures for mitigating the hazard effects of continuous high temperatures on dwarfed Ziziphus jujuba in the plain regions of southern Xinjiang, we conducted a split-plot experiment in a Z. jujuba orchard with three tree forms (open-center shape, OS; low spindle shape, LS; high spindle shape, HS) and two inter-row management practices (grass mulching, GR; clean cultivation control, CK). During a period of continuous high temperatures and irrigation suspension in August of the grass mulching year, we mea-sured air temperature and relative humidity at the upper, middle, and lower parts of the outer canopy (UC, MC, LC) at 10:00 and 16:00 every second day, as well as soil temperature and moisture at different soil depths (10 and 20 cm) under the canopy projection. Then, we analyzed the effects of tree form and inter-row management on microclimate factors. The results showed that: 1) tree form significantly influenced air temperature and soil tempe-rature. Air temperature of HS was reduced by 0.76 ℃ only at 10:00 compared with that of OS, while there was no significant change in LS compared with the other two tree forms. Soil temperature of HS was reduced by 0.98-1.75 ℃ and 0.95-1.29 ℃ compared with that of OS and LS, respectively. Soil temperature of LS was reduced by 0.17-0.46 ℃ compared with OS. 2) Grass mulching significantly influenced all microclimatic factors. Compared with CK, air and soil temperature of GR were reduced by 1.46-3.21 ℃ and 0.82-4.79 ℃, respectively, and the relative humidity of GR was increased by 24.1%-54.9%, but soil moisture of GR increased by 5.3% only at 10:00. 3) There were significant interactions between grass mulching and tree form to affect all microclimate factors, demonstrating strong cooling and humidifying effects. Grass mulching played a dominant role in regulating air temperature and relative humidity at the outer canopy of Z. jujuba trees, while tree form had a weaker adjustment effect. The microclimate indicators of both spindle shaped Z. jujuba trees exhibited higher sensitivity to grass mulching. The interaction between grass mulching and tree form played a prominent role in regulating soil temperature and moisture under canopy projection. In conclusion, inter-row grass mulching could serve as the primary practice for microclimate regulation of Z. jujuba trees, and its combination with spindle-shaped tree forms demonstrated beneficial effect in improving Z. jujuba treeś microclimate and mitigating the negative effects of high temperature in the plain region of southern Xinjiang.

Applicability and application of multiple drought indices to water deficit of staple crops in China

SHI Xiaorui, HONG Xu, ZHU Wenbin

2025, 36(4):  1135-1146.  doi:10.13287/j.1001-9332.202504.023

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In the context of global climate change, the increasing frequency, scale, and intensity of droughts severely threaten food security of China. We established two drought indices (crop evapotranspiration-effective preci-pitation index (CEEP) and water deficit index (WDI)) based on meteorological parameters and crop growth-related data during growing season. The performance of those two indices was compared with that of four widely used ones, i.e., percentage of precipitation anomaly (PA), moisture index (MI), standardized precipitation index (SPI), and standardized precipitation evapotranspiration index (SPEI). We further used the six indices to analyze the characteristics of typical drought events in the winter wheat region of North China and the spring maize region of Northeast China, as well as the spatiotemporal variations of droughts from 1979 to 2018. The results showed that CEEP and WDI effectively captured crop water scarcity and drought characteristics, and WDI was identified as the optimal drought index in more than one-third of provinces, mainly concentrated in Northeast and North China. In terms of temporal variation, based on the WDI, there was no significant trend of drought events in the winter wheat region in North China and the spring maize region in Northeast China. In terms of spatial variation, the performance of the drought indices differed. In the winter wheat zone of North China, PA, MI, and SPI detected more wetting characteristics, while SPEI, CEEP, and WDI detected more drying characteristics. In the spring maize zone of Northeast China, the indices performed more consistency, with wetting trends observed in Suihua, Daqing, and Hegang while drying trends in western part of Jilin and Liaoning, southern Liaoning, western Heilongjiang, and southern Sanjiang Plain. WDI was suitable for crop water deficit analysis in Northeast and North China and could accurately reflect the spatial distribution of drying or wetting trends, which would provide support for water resource management and decision-making in agricultural production.

Carbon footprint of major crop production under the goal of ‘double carbon' in Xinjiang, China

YANG Lu, YUE Kaidi, ZHANG Lijie

2025, 36(4):  1147-1158.  doi:10.13287/j.1001-9332.202503.028

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As the main cotton-producing area and an important production base of food in China, Xinjiang is facing the dual pressures of ensuring national food security and achieving low-carbon agriculture. A comprehensive accounting of carbon footprint of major crops can contribute to decision-making in agricultural structure adjustment and the environmental management in Xinjiang from the perspective of carbon emission reduction. Based on data of the planting area, yield, and agricultural input of wheat, maize, and cotton in Xinjiang from 2005 to 2021, we used the life cycle assessment method to calculate the production carbon footprint of the aforementioned three major crops and used the grey relational analysis to analyze their influencing factors. Results showed that during 2005-2021, the planting areas of wheat and maize varied with the planting area of cotton. The average annual carbon footprint per unit area of wheat, maize, and cotton were 2.21, 2.67, and 3.61 t CE·hm^-2, and the average annual carbon footprint per unit yield were 0.41, 0.35, and 1.91 t CE·t^-1 respectively. The carbon ecological efficiency of the three crops was in an order of wheat (10.99 t CE·t CE^-1) > maize (9.68 t CE·t CE^-1) > cotton (2.96 t CE·t CE^-1), the carbon production efficiency was maize (2.88 t·t CE^-1) > wheat (2.48 t·t CE^-1) > cotton (0.53 t·t CE^-1), and the carbon economic efficiency was cotton (7148.74×10³ yuan·t CE^-1) > maize (6094.32×10³ yuan·t CE^-1) > wheat (5904.23×10³ yuan·t CE^-1). As for carbon input structure, farmland N₂O emission and chemical fertilizer input were the main sources of the production carbon footprint. Total mechanical power, crop planting area, effective irrigation area, agricultural film usage, compound fertilizer and nitrogen fertilizer input were the main driving factors. Based on our analysis of carbon footprint of wheat, maize, and cotton in Xinjiang in 2022 and 2023, we found that this area need to moderately adjust the planting structure in the future. At the same time, it should develop science and technology to improve the utilization efficiencies of chemical fertilizers, agricultural films, irrigation and mechanical operations to achieve the low-carbon production of crops while ensuring the national food security strategy.

Spatiotemporal variation and future scenario simulation of ecosystem carbon storage in the Hulun Lake Basin, Inner Mongolia, China

WANG Qi, SHAN Nan, LI Nannan, ZHANG Zhaoyong, LI Quan, DIAO Rui, WANG Wenlin, QU Yubing

2025, 36(4):  1159-1170.  doi:10.13287/j.1001-9332.202504.024

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Carbon storage in terrestrial ecosystems plays a crucial role in climate change and the global carbon cycle. To investigate the spatiotemporal variations of carbon storage in the Hulun Lake Basin, we combined the InVEST and PLUS models to systematically analyze the impacts of land use changes from 1990 to 2020 on carbon storage, and simulate land use patterns and spatial distribution of carbon storage under different scenarios for 2030. The results indicated that the Hulun Lake Basin experienced significant changes in land use distribution during 1990-2020. The area of cultivated land, forest, bare land, and built-up land increased, while the area of grassland, water, and wetlands decreased. Total carbon storage in the basin increased by 1.48×10⁷ t, with a growth rate of 1.0%. Carbon storage in forest and cultivated land increased by 7.18×10⁷ and 6.7×10⁶ t, while that in grassland, water, and wetlands decreased by 6.01×10⁷, 1.8×10⁶, and 1.7×10⁶ t, respectively. Carbon storage in the basin exhibited significant spatial heterogeneity, with higher carbon storage areas mainly distributed in the eastern hilly areas of the basin and lower carbon storage areas mainly located in the northeastern part of the basin and around Hulun Lake. The spatial differentiation showed a strong coupling relationship with land use patterns. Under the four scenarios for 2030, including natural development, urban development, cropland protection, and ecological conservation,carbon storage in the Hulun Lake Basin showed an increasing trend, with the ecological conservation scena-rio demonstrating the most significant growth of 6.19×10⁶ t and a growth rate of 0.4%. Our findings would provide important references for optimizing land use pattern and enhancing carbon storage capacity in the Hulun Lake Basin.

Spatial distribution and influencing factors of soil dissolved organic carbon in Dongting Lake Basin

DUAN Kangning, HUANG Jinquan, LIU Jigen, KONG Yun, LIU Xiaolan, LI Weiwen, ZHANG Lu

2025, 36(4):  1171-1178.  doi:10.13287/j.1001-9332.202504.012

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Soil dissolved organic carbon (DOC) is a crucial component of terrestrial carbon pool, and its spatial distribution characteristics are of significant importance for the regulation of regional carbon sequestration and the enhancement of carbon sink. Taking the Dongting Lake Basin as the research area, by utilizing geostatistics, correlation analysis, and GIS technology, we analyzed the spatial distribution of topsoil (0-10 cm) DOC and its correlation with environmental variables, including land use types, soil physicochemical properties, and topography. The results showed that: 1) Soil DOC content in the Dongting Lake Basin ranged from 4.31 to 271.29 mg·kg^-1, with an average value of 78.46 mg·kg^-1 and a coefficient of variation of 52.1%, indicating a moderate level of variability. 2) Soil DOC generally exhibited a patchy distribution with a decreasing trend from south to north, showing a moderate spatial autocorrelation with higher variability in the 45°, 90°, and 135° directions due to the joint influences of structural and random factors. 3) Land use patterns, rainfall, slope, soil organic carbon, total nitrogen, and cation exchange capacity were significantly correlated with DOC. Soil physicochemical properties and land use patterns were the main controlling factors affecting the spatial differentiation of soil DOC, with explanation rates of 23.7% and 22.8%, respectively. Our findings would provide a scientific basis for soil carbon sink management and carbon cycle balance in the Dongting Lake Basin.

Land surface temperature effect of afforestation in the Three Gorges Reservoir Area during 2000-2021

ZHANG Zimian, WANG Weiguang, LI Hongbin

2025, 36(4):  1179-1188.  doi:10.13287/j.1001-9332.202504.029

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We employed the window search strategy to investigate the impact of afforestation on land surface temperature (LST) in the Three Gorges Reservoir Area from 2000 to 2021. The inverse distance weighting interpolation method was used to quantify the actual temperature effect of afforestation. The results showed the primary form of land use changes in the Three Gorges Reservoir Area was the conversion between woodland and cultivated land. The potential temperature effect of woodland resulted in a decrease in daytime LST reduction of (0.09±0.02) ℃, a nighttime reduction of (0.06±0.01) ℃, and an annual reduction of (0.07±0.01) ℃ on the interannual scale. The actual temperature effect of afforestation led to a daytime LST reduction of 0.05 ℃, a nighttime reduction of 0.01 ℃, and an annual average reduction of 0.02 ℃. Those results indicated that woodland in the Three Gorges Reservoir Area exhibited a cooling effect during day and night. Furthermore, the cooling effect of the potential temperature was greater than that of the actual temperature, a discrepancy primarily attributed to the differences in the assumptions and handling of afforestation intensity between potential temperature effect and the observed value.

Application of multi-rotor UAV-borne flux observation system in carbon dioxide flux monitoring of reed wetland

JIANG Xiaowen, ZHOU Guangsheng, SONG Xingyang

2025, 36(4):  1189-1196.  doi:10.13287/j.1001-9332.202504.003

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The accurate monitoring of ecosystem carbon flux is the key to scientific assessment of terrestrial carbon sequestration. There is a big challenge for the tower-based eddy covariance system to cover multiple ecosystem types in a region. We introduced a multi-rotor UAV-borne flux observation system, and evaluated its observational accuracy based on the comparison of carbon flux between the multi-rotor UAV-borne flux observation system and the tower-based eddy covariance system within an experiment conducted in the reed wetland of the Liaohe Delta from July 27 to 29, 2023. The results showed that the multi-rotor UAV-borne flux observation system could monitor ecosystem carbon flux well, and the observed carbon flux source area was basically consistent with the eddy covariance system. The half-hour ecosystem carbon flux was significantly correlated with the observation results of the eddy correlation system, with a correlation coefficient of 0.889 and a root mean square error of 0.881. Our results provided a scientific basis for using the multi-rotor UAV-borne flux observation system to monitor ecosystem-atmosphere flux exchange across different ecosystem types.

Relationship between meteorological, soil, and hydrological drought propagation at different levels in Inner Mongolia, China

ZHANG Mengmeng, GUO Enliang, WANG Yongfang, KANG Yao, ZHAO Jiapei, WU Jisiguleng, LUO Xiao

2025, 36(4):  1197-1210.  doi:10.13287/j.1001-9332.202504.027

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Understanding the meteorological-soil-hydrological drought propagation characteristics can provide technical supports for the formulation of drought mitigation measures. Taking Inner Mongolia as the research area, we utilized the ERA5-Land soil moisture and surface runoff dataset from the European Centre for Medium-Range Weather Forecasts from 1980 to 2022, coupled with observation data from 115 meteorological stations, to calculate standardized precipitation evapotranspiration index (SPEI), standardized soil moisture index (SSI), and standar-dized runoff index (SRI) at different temporal scales. Then, we used run theory, Theil-Sen median trend analysis, the Mann-Kendall test, and Pearson correlation analysis to investigate the lag effects across different types of droughts and the spatiotemporal distribution of propagation time. The results showed that over 85% of the region showed an intensifying trend for meteorological, soil, and hydrological droughts, with areas showing significant wetting covering less than 1% of the study area. Meteorological drought events were characterized by high frequency, low severity, and short duration, whereas soil drought events exhibited low frequency, high severity, and long duration. Hydrological droughts were dominated by high frequency, low severity, and short-duration events. The response between soil and hydrological drought was stronger than that between meteorological and hydrological drought, implicating that soil moisture deficit induced by soil drought was the primary trigger for hydrological drought. The propagation time for various levels of droughts was predominantly concentrated between two to six months, with higher-grade drought events showing more efficient transition and propagation. The continuity of meteo-rological, soil, and hydrological drought events in central and western Inner Mongolia and soil-hydrological drought events in eastern Inner Mongolia were relatively weak. This research would be of great significance in revealing the mechanisms of regional drought formation and constructing drought propagation models.

Spatial and temporal evolution of ecological risk in Guizhou Province, China from the perspective of ecosystem services and ecosystem health

DONG Wenzhuo, SU Weici, GOU Rong, ZHOU Hengyang, LIU Dongyue

2025, 36(4):  1211-1221.  doi:10.13287/j.1001-9332.202504.021

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Guizhou Province is an important ecological barrier in the upper reaches of the Yangtze River and the Pearl River. Karst landform in Guizhou is developed, with fragile ecological background. The ecological risk assessment and control of Karst landform are of great significance to ecological security and sustainable development of southwest China and the upper reaches of those two rivers. Based on the InVEST model and vigor-organization-resi-lience model, we quantitatively evaluated the ecosystem services and ecosystem health and constructed the ecological risk assessment model of Guizhou Province. With the help of GIS technology, spatial autocorrelation analysis method and gravity center migration model, we analyzed the spatial and temporal variations of ecological risk in Guizhou Province from 2000 to 2020. The results showed that ecosystem services in Guizhou Province increased from 2000 to 2020, with an annual average growth rate of 0.3%. The ecosystem health status was generally well and showed a good trend, and the annual average growth rate of ecosystem health was 12.6%. The ecological risk was dominated by medium ecological risk. The proportion of extremely low ecological risk area and low ecological risk area increased, the proportion of medium and above ecological risk area decreased, and the overall ecological risk showed a downward trend. The low ecological risk areas were mainly located in the south and southeast of Guizhou Province, while the high ecological risk areas were distributed in the central, western and northern parts of Guizhou Province. The global Moran's I of ecological risk in 2000, 2005, 2010, 2015, and 2020 were 0.856, 0.836, 0.844, 0.804, and 0.768, respectively, indicating that the positive correlation of ecological risk in spatial distribution, but the spatial correlation and spatial agglomeration characteristics were weakened. During the study period, the centroid and trajectory of ecological risk in Guizhou Province were consistent with the distribution area of its corresponding ecological risk. From 2000 to 2020, the spatial distribution pattern of ecological risk in Guizhou Pro-vince was relatively stable. With the evolution of time, the dispersion of spatial distribution of extremely high ecological risk and low ecological risk increased. Ecological risk assessment based on ecosystem services and ecosystem health would provide scientific basis for regional ecological risk management and control.

Vegetation cover changes and their responses to natural and anthropogenic factors in the Luanhe River Basin

FENG Ping, YANG Wang, LI Jianzhu, YANG Nijuan, DUAN Jiacheng

2025, 36(4):  1222-1232.  doi:10.13287/j.1001-9332.202504.022

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Dynamically assessing vegetation cover changes and their responses to ecological factors in the Luanhe River Basin is crucial for ensuring regional ecological security and promoting the sustainable development of the Beijing-Tianjin-Hebei urban agglomeration. In this study, the Luanhe River Basin was divided into two ecological zones (Inner Mongolia Plateau Ecoregion and North China Mountain Ecoregion). Using Theil-Sen median trend analysis, the Mann-Kendall test, and the optimal parameters-based geographical detector model, we systematically analyzed the spatiotemporal characteristics of vegetation change from 2000 to 2019 and quantified the effects of natural and anthropogenic factors. The results showed that the normalized difference vegetation index (NDVI) exhibited an overall increasing trend with fluctuations from 2000 to 2019, with a mean value of 0.72 and a growth rate of 0.0051·a^-1. The NDVI growth rate in the upstream plateau ecological zone was higher but less stable, whereas vegetation in the midstream and downstream mountain ecological zone exhibited greater stability. Annual precipitation, annual sunshine duration, and land-use type conversion were identified as key drivers of NDVI variation, with explanatory power (q-values) of 0.22, 0.18, and 0.17, respectively. Among them, the interaction between annual precipitation and soil type was the most significant (q=0.32). Land use changes significantly contri-buted to vegetation improvement, with an average NDVI increase of 0.16 in ecological restoration project areas. By revealing the synergistic mechanism of natural and anthropogenic factors on vegetation cover changes, our results provide scientific support for ecological conservation and land management policies in the Luanhe River Basin.

Wilderness network construction in Lincang City of Yunnan Province, Southwest China based on landscape connectivity

LI Yuanhang, ZHANG Yun

2025, 36(4):  1233-1243.  doi:10.13287/j.1001-9332.202504.026

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Constructing wilderness networks based on landscape connectivity is crucial for wilderness conservation. We calculated the continuous spectrum of the wilderness with GIS, identified wilderness sources with morphological spatial pattern analysis (MSPA), constructed wilderness corridors and networks and extracted wilderness strategic points with minimum cumulative resistance model (MCR) and circuit theory. We further analyzed the characte-ristics of the wilderness network, and proposed wilderness protection strategies and ecological planning suggestions for Lincang City. Results showed that wilderness was mainly distributed at 1000-2500 m elevation, with a spatial pattern of more in the south and east, less in the north and west in Lincang City. Grade 3 wilderness covered 55% of the total area, indicating high quality of the study area. Based on the MSPA analysis, we found 27 wilderness sources, most of which were distributed in the eastern and southern areas such as Linxiang and Cangyuan. The western and northern such as Fengqing and Yongde had fewer wilderness sources. There were 63 wilderness corridors in the wilderness network, including 16 important corridors and 47 general corridors. There were 186 strategic points in the wilderness network, including 53 wilderness nodes and 133 barrier points. We constructed the wilderness network of Lincang based in the identified wilderness source areas and extracted wilderness corridors, which had the advantages of high stability, strong resistance to interference, efficient connectivity. Finally, we proposed the “three-zone as a whole” protection strategy and ecological planning suggestions, which had referential value for establishing an ecological security pattern in Lincang City and the practicalization of wilderness protection in China.

Repellency of volatiles from bracts of banana flower bud to Frankliniella occidentalis

FENG Chencheng, LI Xundong, MAO Jia, XU Shengtao, XIA Tiyuan, LING Hui, LIU Lina, YIN Kesuo

2025, 36(4):  1244-1250.  doi:10.13287/j.1001-9332.202504.033

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Frankliniella occidentalis infested a wide range of crops. However, no F. occidentalis was found on banana flower bud. To investigate the effect of volatile of banana bud on the behavior of F. occidentalis, we utilized Y-tube olfactometer to assess the behavioral responses of F. occidentalis to different tissues of banana flower buds. We further analyzed the volatile of bracts of flower bud by gas chromatography-mass spectrometry (GC-MS), to select and test the relatively high abundant compound. We determined their behavioral effect on F. occidentalis by conducting an activity experiment in rose garden. The results showed that flower stamen and pistil, as well as young fruit had an attractive effect on F. occidentalis, with relative selection rates of 37.3% and 35.8% respectively. The bracts exhibited a strong repellent effect, with a relative selection rate of -68.6%. Among the 35 volatile compounds detected from the bracts, eight compounds had a relative content more than 1%, accounting for 61.6% of the total. They were α-pinene (16.8%), β-pinene (14.6%), D-limonene (7.9%), DL-limonene (7.9%), ocimene (6.4%), β-caryophyllene (4.8%), 1,8-cineole (4.1%), and γ-terpinene (1.0%). The α-pinene, D-limonene, and β-caryophyllene had significantly repellent effect on F. occidentalis. The relative selection rates were -52.0% and -35.8% at 10.0 μg·mL^-1 and 1.0 μg·mL^-1 for α-pinene, were -43.4% at 1.0 μg·mL^-1 for β-pinene, were -34.6% at 10.0 μg·mL^-1 for D-limonene, were -56.9% at 1.0 μg·mL^-1 and -28.3% at 0.1 μg·mL^-1 for DL-limonene, were -32.1% at 10.0 μg·mL^-1 and -33.3% at 1.0 μg·mL^-1 for β-caryophyllene, respectively. Results of the outdoor trial showed that the five tested compounds exhibited significantly repellent effects on F. occidentalis. The relative selection rates were -51.6% for α-pinene at 10.0 μg·mL^-1 and the lowest were -22.8% for β-caryophyllene at 1.0 μg·mL^-1. In conclusion, the bracts of banana flower buds were the key important tissue to repellent F. occidentalis, with α-pinene, β-pinene, D-limonene, DL-limonene, and β-caryophyllene as the core compounds.

Predicting the impact of climate change on the habitat distribution of Grus nigricollis based on the MaxEnt model

LUO Caihong, WANG Wanyu, HUANG Jinxia, WANG Peng, MA Maohua, CHEN Jilong, ZHAO Cunfeng

2025, 36(4):  1251-1260.  doi:10.13287/j.1001-9332.202504.032

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Under the context of global climate change, the shifts in suitable habitats of different species have become one of the major threats to biodiversity. We simulated the distribution habitats of Grus nigricollis under current climatic condition and predicted potential changes under three climate scenarios (SSP126, SSP245, and SSP585) with the MaxEnt model based on the distribution records of G. nigricollis and environmental variables. The results showed that: 1) Elevation, annual temperature range, and mean temperature of the wettest quarter were the main environmental factors affecting the distribution of potential breeding habitats for G. nigricollis, while the wintering habitats were significantly influenced by factors such as isothermality, elevation, and temperature annual range. 2) Under the current climate condition, the breeding habitats of G. nigricollis were mainly distributed in Xinjiang, Gansu, Qinghai, Tibet, Sichuan of China, as well as India, with a highly suitable breeding area of 27.07×10⁴ km². The wintering grounds were primarily located in Tibet, Sichuan, Yunnan of China, as well as Bhutan, Nepal, India, and Myanmar, with a highly suitable wintering area of 21.15×10⁴ km². 3) Under future climate scenarios, the overall potential suitable habitats for G. nigricollis remained stable, with the retention rate of stable areas exceeding 80%. Among these, the breeding habitats showed an increasing trend, while the wintering habitats exhibited a decreasing trend. 4) Under different climate scenarios, the centroid of breeding ground of G. nigricollis would gene-rally move southeastward, while the centroid of wintering ground mainly moved westward, potentially reducing migration distance. By predicting the changes in the potential suitable habitat for G. nigricollis on a large regional scale under future climate scenarios and revealing the impact of climate change on their distribution, this study could provide a scientific basis for the conservation of G. nigricollis and the formulation of relevant strategies.

Composition and spatiotemporal variation of macroalgae in large-scale raft culture area of Gouqi Island, Zhejiang, China

LI Jingjing, WANG Zhenhua, ZHANG Shouyu, LIN Jun, WANG Kai, ZHAO Xu

2025, 36(4):  1261-1271.  doi:10.13287/j.1001-9332.202504.031

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To comprehensively understand the impacts of large-scale raft culture activities on the diversity and biomass of macroalgae, we collected samples monthly from July 2021 to June 2022 in the Gouqi Island mussel farming area (raft culture area) and the natural rocky intertidal zone (control area). By using indices such as Shannon diversity, Margalef richness, Pielou evenness and relative importance index, as well as redundancy analysis, we compared the responses of alpha diversity, growth cycle, biomass spatiotemporal patterns of macroalgae to environmental factors in both raft culture area and control area. The results showed that a total of 61 macroalgae species were collected in the raft culture area, belonging to 13 orders, 25 families, and 31 genera. There were 24 dominant macroalgae species annually, among which Jania decussato-ichotoma, Pachymenia carnosa, and Chaetomorpha aerea dominated in most of months. 47 species of macroalgae, belonging to 31 genera and 24 families in 13 orders, were collected in control area. There were 13 dominant species, but only Sargasum thunbergii dominated throughout the year. The vigorous growth period of macroalgae represented by Hypnea cervicis, Hypnea boergesenii, P. carnosa, Grateloupia sp., J. decussato-dichotoma, Ulva lactuca, Ulva fasciata and Sargasum horneri in raft culture area significantly increased. Shannon index and Margalef index of macroalgae in raft culture area (2.36±0.25 and 1.45±0.23, respectively) were higher than those in control area (1.85±0.32 and 0.96±0.39, respectively). The macroalgae biomass in raft culture area exhibited a notable monthly variation, with a mean biomass of (10374.53±4688.17) g·m^-2, which was considerably higher than that in the control area (3090.40±2230.33 g·m^-2). In terms of spatial distribution, the mean monthly biomass was higher in nearshore region of raft culture area (11466.12±227.65 g·m^-2) than that to the outer region (10498.29±1266.77 g·m^-2) and the middle region (9229.95±252.75 g·m^-2). The redundancy analysis indicated that transparency, salinity, dissolved oxygen, water temperature, turbidity, and ammonium nitrogen were significantly correlated to community structure. Those results indicated that large-scale raft culture area supported both higher diversity and biomass of macroalgae than intertidal zones. Meanwhile, dominant macroalgae such as J. decussato-ichotoma, P. carnosa and S. horneri presented extended periods of vigorous growth in artificial habitat. The conclusions could be taken into consideration on construction of raft macroalgal bed in marine ranching programs.

Reviews

Concepts, boundaries, and trade-offs of coastal blue well-being

ZHANG Yaowen, DAI Qiongyao, YE Guanqiong

2025, 36(4):  1272-1280.  doi:10.13287/j.1001-9332.202504.035

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Marine ecosystems provide material resources and development space for human production and life, which is crucial to economic development and human well-being. Coastal blue well-being refers to the positive states of human life in coastal areas supported by ecosystem services, including subjective emotional and cognitive dimensions as well as the objective natural, economic, and social dimensions. How to achieve the dual goals of protecting the ocean and improving human well-being is a core issue in ensuring marine sustainable development. When considering the connotation of coastal blue well-being, it is necessary to analyze the relationship between marine ecosystems and human well-being, and identify the coastal blue well-being components related to ecosystem services. Here, we sorted out the linkage framework and trade-off relationship between marine ecosystem services and coastal blue well-being based on the theory of well-being, and clarified the evaluation dimension of coastal blue well-being. This study would provide theoretical supports for dynamic monitoring of coastal blue well-being and the trade-off of related interests, as well as a theoretical basis for the program of improving coastal blue well-being.

Connotation, characteristics, significance, and development pathways of new quality productive force in agriculture

HUANG Guoqin

2025, 36(4):  1281-1288.  doi:10.13287/j.1001-9332.202504.040

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Since General Secretary Xi Jinping first proposed the concept of “new quality productive force” in September 2023, the term “new quality productive force in agriculture” has also been proposed and attracked increased attention. The new quality productive force in agriculture is the application and specific expression of the new quality productive force in the area of agriculture. Its essence is the transformation, application and industrialization of modern high-tech achievements in agriculture, aiming to generate new industry, new business type, new mode, new kinetic energy, and new functions, to achieve high efficiency of resources, high efficiency of production, high speed of development, high quality of products, and high-quality talents, to promote the modernization of agriculture and rural areas, and ultimately to build a powerful agricultural country. Compared with the traditional agricultural productivity, there are eight new characteristics in new quality productive force of agriculture, including progressiveness, low-carbon, efficient, diversified, innovative, integrated, shared, and high-end. Developing new quality productive force of agriculture has important theoretical and practical significance. Firstly, it is conducive to increasing agricultural output and maintaining food security. Secondly, it would promote the increase of farmerś income and the prosperity of rural economy. Thirdly, it helps improve agricultural efficiency and build a strong agricultural country. Fourthly, it could advance the ecological environment and build a beautiful China. Fifthly, it would help lead the development of world agriculture and promote the construction of a community with a shared future for mankind. The main pathways for cultivating and developing the new quality productive force of agriculture include: strengthening scientific and technological innovation, collecting ‘high-quality' data, developing new types of machinery and tools, developing new quality industries, optimizing the ecological environment, cultivating new quality talents, and establishing a new system.