Table of Content

10 November 2021, Volume 40 Issue 11

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Trade-offs and synergies of ecosystem services in forest barrier belt of Northeast China.

QI Lin, ZHANG Yue, XU Dong, ZHU Qi, ZHOU Wang-ming, ZHOU Li, WANG Qing-wei, YU Da-pao

2021, 40(11):  3401-3411.  doi:10.13292/j.1000-4890.202111.020

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Northeast forest belt is an important ecological barrier in China. Understanding the trade-offs of ecosystem services is important to coordinate ecological environment protection and social development in this region. In this study, we used spatial autocorrelation analysis, bivariate spatial correlation analysis, and spatial clustering analysis methods to quantify the spatial patterns of six selected ecosystem services, and reveal underlying mechanisms of trade-offs and synergies and spatial variation. The results showed that the six selected ecosystem services showed a significant aggregation distribution. At regional scale, the services of water conservation, biodiversity maintenance, soil conservation and carbon sequestration showed a systematic relationship, while the services of sand fixation and food supply showed a trade-off relationship with other ecosystem services. Ecosystems provide a variety of services, and the types and quantities of ecosystem services provided by different ecosystems were significantly different. Therefore, the trade-off/synergy relationship among different ecosystem services also showed significant spatial variation. The study area was divided into ecosystem service balance zone, ecosystem service coordination zone, sand fixation zone, and food supply zone through ecosystem service clusters, in order to provide a scientific basis for the management of ecosystem services and promote the comprehensive, coordinated, and sustainable development of resources and ecological environment.

The construction and optimization of ecological security pattern in the eastern part of the sand prevention belt in Northern China.

LIU Jiang, XIE Zun-bo, WANG Qian-hui, WANG Ting-ting, ZHENG Xiao, SONG Li-ning, LI Xiu-fen

2021, 40(11):  3412-3423.  doi:10.13292/j.1000-4890.202111.018

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Constructing ecological security patterns and optimizing ecological spatial structure are important ways to guarantee regional ecological security and ecosystem stability, with positive significance for alleviating the contradiction between ecological protection and economic development. Taking the eastern part of the sand prevention belt in Northern China as study area, we identified ecological sources through the ecological assessment method of ecological vulnerability and importance of ecological service function, extracted ecological corridors and ecological nodes with the circuit theory, constructed a two-phase ecological security pattern in 2000 and 2015, and put forward the optimization measures. The results showed that: (1) From 2000 to 2015, the area of highly vulnerable areas decreased, whereas that of non-vulnerable areas increased. The overall habitat quality improved, the water conservation significantly increased, and the actual wind erosion intensity weakened. Those results indicate that regional ecological environment tended to improve and the sand control had achieved remarkable results. (2) The areas of ecological sources, ecological corridors, and nodes increased from 3837.3 km², 38, and 4 in 2000 to 11619.5 km², 96, and 28 in 2015, respectively. Such a result indicated that the network system of ecological security pattern in the study area tended to be complex and perfect in the past 15 years, and the ability to guarantee ecological security had been improved. Accordingly, we should increase the number and scope of ecological sources, strengthen the construction and protection of artificial green areas to set buffer zones, avoid cutting off ecological corridors by human activities, and strengthen the protection and optimization of ecological functions of the original nodes, to guarantee the integrity of the ecological corridor network. This study provides a reference for promoting a synergistic and mutually beneficial relationship between regional socio-economy and ecological environment and achieving sustainable development.

The evolution and differentiation trend of ecological land pattern in the Yellow River Basin from 2000 to 2020.

WEI Xin-dong, ZHANG Jian, WANG Shai-ni, LIN Kang-li, WANG Ning, LIU Yong-peng

2021, 40(11):  3424-3435.  doi:10.13292/j.1000-4890.202111.019

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Analysis of the evolution and differentiation trend of ecological land pattern under the interaction of human activities and natural environment is of great significance for the ecological protection and high-quality development of the Yellow River Basin. Based on land use data of the Yellow River Basin in 2000, 2010, and 2020, we used spatial dynamic model, transfer matrix model, and ecological index model to explore the change trend of the number, structure, spatial distribution, and ecological quality of ecological lands in the Yellow River Basin in the past two decades. The results showed that the quantity and spatial distribution of different types of ecological lands in the Yellow River Basin were quite different. Basic ecological land accounted for the largest proportion (60.98%), whereas conservation ecological land accounted for the least (4.77%). Basic and conservation ecological land were mainly distributed in the upper and middle reaches of the Yellow River Basin, while auxiliary ecological land was mainly concentrated in the lower reaches. The transformation among different types of ecological lands showed an obvious differentiation, with the internal transformation of ecological lands occurring in the upper and middle reaches and the mutual transformation between ecological land and nonecological land in the lower reaches, and the expansion of nonecological land mainly from cultivated land. The spatial stability of ecological lands in the Yellow River Basin was relatively high, but with a downward trend. On the whole, ecological lands tended to decrease in scale. The ecological status index of the three years in the Yellow River Basin was 60.98, 61.66, and 60.29, respectively. The ecological quality showed a fluctuating decline and had obvious characteristics of gradient differentiation. The ecological quality was the best in the upper reaches and the worst in the lower reaches. Our results provide reference for the provinces in the Yellow River Basin to formulate ecological land management and protection measures and promote the construction of ecological civilization.

Spatiotemporal variations of wind prevention and sand fixation function in the sand-prevention belt in Inner Mongolia in recent 15 years.

LIU Li-min, WANG Ting-ting, LI Xiu-fen, XIE Zun-bo, WU Jin-zhou, SONG Li-ning

2021, 40(11):  3436-3447.  doi:10.13292/j.1000-4890.202111.007

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The wind prevention and sand fixation function are the main ecological service function of sand-prevention belt in northern China, which is important for the construction of ecological safety barrier in northern China. In this study, the sand-prevention belt in Inner Mongolia was selected as the study region, the revised wind erosion equation (RWEQ) was applied to quantify soil wind erosion mass and wind prevention and sand fixation mass in 2000 and 2015. We analyzed the spatial and temporal variations of wind prevention and sand fixation function, and the effects of land-use change on wind prevention and sand fixation function, aiming to provide reference for improving ecological service function of sand-prevention belt in northern China. The results showed that: (1) soil wind erosion mass ranged from 0.007 to 48.9 kg·m^-2 in 2000, with a total soil wind erosion mass of 29418.3×10⁸ kg, while it ranged from 0.002 to 48.2 kg·m^-2 in 2015, with a total soil wind erosion mass of 28727.3×10⁸ kg. From 2000 to 2015, the total amount of wind erosion in the whole region reduced by 691.1×10⁸ kg. The intensity of soil wind erosion was mainly moderate, intensive, and severe, which together accounted for 71.6% of the total area in 2000, while it was mainly slight, moderate, and severe, accounting for 78.7% of the total area in 2015. The area of the regions with soil wind erosion of intensive, extreme, and severe intensity decreased by 101079 km², while the area with soil wind erosion of mild and moderate intensity increased by 100572 km². (2) The average amount of wind prevention and sand fixation per unit area ranged from 0 to 42.4 kg·m^-2 in 2000, while it ranged between 0 and 45.4 kg·m^-2 in 2015. The average amount of wind prevention and sand fixation per unit area was the highest in Chifeng City, followed by Tongliao and Ordos cities, while Wuhai and Shizuishan cities had the lowest values. The total amount of wind prevention and sand fixation in the study region was increased by 646.0×10⁸ kg from 2000 to 2015. The level of wind prevention and sand fixation functions was mainly low, relatively low, and medium, together accounting for more than 75% of the total area. The area with wind prevention and sand fixation functions of relatively high and high levels increased by 1979 km². (3) From 2000 to 2015, the total area of desertdecreased and was mainly converted into grassland and cultivated land. The converted grassland area was 6460.7 km², while the converted cultivated land area was 439.2 km². Our results indicated that the capability of wind prevention and sand fixation function in the sandprevention belt in Inner Mongolia significantly was improved over the past 15 years due to revegetation, but varied greatly among different parts of the study region. Therefore, we should take different strategies in different sand-fixing function zones, and pay more attention to the improvement of sand-fixing function in the western part.

Ecological pattern optimization of forest barrier belt in Northeast China based on GeoSOS-FLUS.

QI Lin, XU Dong, ZHU Qi, ZHOU Wang-ming, ZHOU Li, WANG Qing-wei, DENG Jiao-jiao, YU Da-pao

2021, 40(11):  3448-3462.  doi:10.13292/j.1000-4890.202111.011

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Northeast forest belt is an important carrier of ecological security pattern of China. It is of great significance to optimize its ecological pattern for improving the ecosystem function and stability. In this study, we analyzed the spatial and temporal patterns of land use and ecosystem services, and identified the major driving factors. With the aim to improve the dominant ecological functions of the Northeast China forest belt, we coupled the driving mechanism of ecological services, and used a cellular automata model to optimize its land use pattern. The results showed that the effects of different driving factors on ecosystem services were significantly different. Habitat quality had the strongest correlation with land use (R=-0.420, P<0.05). Water supply was significantly affected by annual precipitation (R=0.602, P<0.05). Soil conservation was significantly affected by elevation (R=0.358, P<0.05). Water conservation was closely related to precipitation (R=0.760, P<0.05), while food supply was affected by elevation (R=-0.418, P<0.05), slope (R=-0.225, P<0.05) and temperature (R=0.306, P<0.05). The coniferous and broadleaved mixed forests were the most important for water conservation and habitat quality. Paddy field was more important for food production than  dry farmland. The results of land use optimization simulation showed that the proportion of ecological land (including forest, grassland, and wetland), productive land (paddy field and  dry farmland) and living land (construction land) was not significantly different from that before optimization. However, forests in Changbai Mountain and Lesser Khingan should be changed from deciduous broadleaved forest to coniferous and broadleaved mixed forest to improve water conservation and habitat quality. The Greater Khingan region should transform part of the deciduous broadleaved forest into wetlands to improve water conservation in the area. Under the condition of controlling the total amount of cultivated land without obvious change, increasing the proportion of paddy field in the intersection area between Lesser Khingan and Changbai Mountain and Sanjiang Plain can improve food supply service. In conclusion, this study could help optimize the ecological pattern of the study area without further aggravating the spatial contradiction between ecological land and other land use types, which provides a scientific basis for promoting the dominant ecological function of Northeast China forest belt and giving full expression of its barrier function.


Construction of ecological security network of Northeast China forest belt based on the circuit theory.

ZHU Qi, YUAN Quan, YU Da-pao, ZHOU Wang-ming, ZHOU Li, HAN Yan-gang, QI Lin

2021, 40(11):  3463-3473.  doi:10.13292/j.1000-4890.202111.012

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Northeast China forest belt is an important part of the national ecological function regionalization “two screens and three zones”, which is of regional and national significance for ecological security. The construction of ecological security network in this region is an important basis for the optimization of ecological pattern and its function improvement. We used the habitat quality analysis module in InVEST model and the circuit theory to identify the ecological sources, corridors, barriers and pinch points, and constructed the ecosystem service security network of Northeast China forest belt. The results showed that there were 30 ecosystem service sources in the study area, with a total area of 16.40×10⁴ km², accounting for 27.3% of the study area, and that woodland, wetland and other ecological lands were the main components. There are 42 key ecological corridors with a total length of 2475.55 km, and 20 potential ecological corridors with an average length of 420.55 km. The area of the ecological improvement zone is 56.45×10⁴ km². According to the improvement degree of accumulated current value, the  restoration area is classified into three levels, with the first and second level restoration zones accounting for 12.8% and 24.3%, respectively. Based on distribution pattern of the ecological sources, ecological corridors, ecological pinch points, ecological barriers, and ecological restoration zones, we constructed the ecosystem service security network of the study area, and provided suggestions for restoration and improvement according to its characteristics. Our results would provide scientific basis for its ecological pattern optimization and function improvement in the study area.

Spatiotemporal changes and driving factors of ecological vulnerability in Northeast China forest belt.

ZHU Qi, Wang Ya-nan, ZHOU Wang-ming, ZHOU Li, YU Da-pao, Qi Lin

2021, 40(11):  3472-3482.  doi:10.13292/j.1000-4890.202111.021

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Assessing the vulnerability of large-scale forest ecosystems is of great significance for maintaining regional ecological security and ensuring sustainable development of our society. In this study, we selected 13 indicators to construct the ecological vulnerability index system of Northeast China forest belt from the perspective of natural and anthropogenic disturbances. Combined with the spatial principal component analysis, we evaluated the spatial and temporal distribution and changes of ecological vulnerability in the forest belt in 2005 and 2015, and analyzed the main driving factors. The results showed that the ecological vulnerability of the forest belt was mainly potential vulnerability, slight vulnerability, and light vulnerability, with the ecological vulnerability at low level. The spatial aggregation effect of ecological vulnerability was strong and mainly comprised of high-high aggregation. Area with high-high aggregation was mainly distributed near the border of the forest belt. The regional ecological vulnerability index in 2005 and 2015 was 2.339 and 2.450, respectively, showing a slightly worse trend. The main driving factors of ecological vulnerability of the forest belt in the two periods were net primary productivity, land use type, and habitat quality. Our results provide a theoretical basis and decisionmaking basis for large-scale forest ecosystem protection and management.

Spatiotemporal variation of net primary productivity of spruce-fir forest at high altitudes and the driving forces  in Changbai Mountain Nature Reserve.

ZHANG Yue, YUAN Quan, FANG Lei, HAN Yan-gang, ZHU Qi, QI Lin, ZHOU Wang-ming, ZHOU Li, YU Da-pao

2021, 40(11):  3483-3492.  doi:10.13292/j.1000-4890.202111.013

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Spruce-fir forests at their upper distribution (above 1400 m) in Changbai Mountain Nature Reserve showed growth decline and die-off, but the decline pattern and underlying mechanism are unclear. In this study, based on Landsat data from 1994 to 2019, we calculated the net primary productivity (NPP) by CASA model and analyzed the spatiotemporal variation of NPP in sprucefir forests at their upper distribution in Changbai Mountain Nature Reserve. Results showed that: (1) NPP of spruce-fir forest varied within 111.96-182.19 g C·m^-2·a^-1, with a mean value of 141.85 g C·m^-2·a^-1. From 1994 to 2019, the maximum and minimum NPP in spruce-fir forest occurred in 1996 (182.19 g C·m^-2·a^-1) and 2018 (111.96g C·m^-2·a^-1), respectively. (2) ^The NPP of spruce-fir forest was negatively correlated with elevation and slope, and there was no significant difference in its distribution among different aspects. In the range of 1600-1650 m, the change rate of NPP was close to zero, while NPP at lower and higher altitudes was decreasing. The decreases of NPP of spruce-fir forest were the most obvious when the slope was within the range of 0-10°, and the variation trend of NPP decreased with increasing slope. The increases of NPP showed a trend of decline on shady slope and semi-shady slope, but tended to be stable on sunny slope and semi-sunny slope. (3) The NPP of spruce-fir forest was positively correlated with precipitation, but not related with temperature. The decrease in NPP was partly related to tourism activities in the protected areas. Our results indicated that there was no consistent, large area decline in the high altitude spruce-fir forest, and the variation of NPP was mainly affected by site factors, precipitation, and human activities.

Plastic responses of N and P concentrations in typical plant species to short-term nitrogen input in tundra zone of the Changbai Mountain, China.

YUAN Quan, ZHANG Yue, CHEN Hong, ZHOU Li, YU Da-pao, WANG Qing-wei, ZHOU Wang-ming

2021, 40(11):  3493-3500.  doi:10.13292/j.1000-4890.202111.014

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Nitrogen (N) is a major limiting element for plant growth and net primary productivity in tundra. However, the effects of exogenous N input on plant nutrient concentrations of tundra in Changbai Mountain remain unclear. In this study, we examined the effects of short-term N (as NH₄NO₃) input on foliar N and P concentrations of Vaccinium uliginosum and Rhododendron chrysanthum, two dominant species of tundra in Changbai Mountain, under four treatments \[control (N0, 0 kg·hm^-2), low N (N1, 25 kg·hm^-2), medium N (N2, 50 kg·hm^-2), and high N (N3, 100 kg·hm^-2)\]. Low N input increased foliar N concentration ofR. chrysanthum, but did not affect N and P concentrations in V. uliginosum. However, a higher N input promoted the growth ofV. uliginosum and increased its ability to acquire N and P. With increased nitrogen input, the plasticity index (PI) of N and P concentrations in V. uliginosum (deciduous shrub) decreased first and then increased, while that ofR. chrysanthum (evergreen shrub) always decreased. The stress resistance of R. chrysanthum was higher than that of V. uliginosum. Under the scenario of increasing N deposition, V. uliginosum will have more growth advantages in the tundra zone of Changbai Mountain.

Species composition and community structure of Miyaluo subalpine dark coniferous forest dynamic plot in western Sichuan, China.

ZHAO Guang-dong, CHEN Jian, XU Ge-xi, MA Fan-qiang, YANG Hong-guo, SHI Zuo-min, LIU Shun, XIONG Kai, ZHANG Yun, XUE Qiao, LIU Qian-li

2021, 40(11):  3501-3511.  doi:10.13292/j.1000-4890.202111.016

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Subalpine dark coniferous forest is the dominant vegetation in Miyaluo forest region of the western Sichuan. To better understand species composition and community structure of subalpine dark coniferous forest in the southeastern edge of the Tibetan Plateau, a 9.6 hm² forestdynamics plot was established in Sichuan Miyaluo Provincial Nature Reserve from 2016 to 2019, following the field protocol of the Center for Tropical Forest Science (CTFS) and the Chinese Forest Biodiversity Monitoring Network (CForBio). In this study, we analyzed the floristic types, species composition, community structure, and DBH size distribution on the basis of the data collected from all living woody plants with diameter at breast height (DBH) ≥1 cm. The results showed that there were 50055 living stems in total, including 24183 independent individuals and 25872 branching or sprouting stems, belonging to 32 species, 20 genera, and 14 families. The numbers of families and genera of temperate floristic elements accounted for 64.28% and 85.00%, respectively. Juniperus squamata, Picea asperata, Berberis dictyoneura,and Buddleja forrestii were the rare species, which together accounted for 12.50% of the total species richness. Ten species with importance value (IV) >2 had a total IV value of 90.54. The IV of top four dominant species, Abies fargesiivar. faxoniana, Betula utilis, Juniperus convallium, and Ribes luridumwas 30.55, 15.74, 9.95, and 8.80, respectively. When plot area was less than 1.6 hm², the number of species increased rapidly with the increasing area. When plot area reached 6.76 hm², all of the 32 species appeared. The mean DBH of all living individuals in the whole plot was 5.29 cm. The DBH size distribution of all living individuals showed an inverse “J” type. The stems with DBH <2.5 cm represented 59.63% of the total individuals in the whole plot.

Interspecific association of main species in shrub layer of Pinus tabuliformis aerial seeding forest and the environmental interpretation.

CHEN Jia-hui, BU Yuan-kun, SU Shao-feng, HUANG Wei, CHEN Zhou-juan, LI Wei-zhong

2021, 40(11):  3512-3522.  doi:10.13292/j.1000-4890.202111.022

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niche|interspecific association| association coefficient| canonical correspondence analysis (CCA).


Distribution characteristics of soil organic carbon content and density in Zoige wetland.

WANG Wen-bo, BAI Bing, ZHANG Peng-qian, HU Li-le

2021, 40(11):  3523-3530.  doi:10.13292/j.1000-4890.202111.006

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Wetlands are an important reservoir of soil organic carbon and provide an important guarantee for maintaining global carbon dioxide balance. In this study, we collected soil samples at different depths of different vegetation types (wetland vegetation and grassland) from alpine wetland in Zoige, to analyze the horizontal and vertical variation characteristics of soil organic carbon. We found two different characteristics of the vertical distribution of soil organic carbon. First, the content and density of soil organic carbon decreased significantly with increasing soil depth, with the difference between maximum and minimum values being 20.03 times and 7.47 times, respectively. Second, the content and density of soil organic carbon fluctuated with increasing soil depth, and maintained a high level in deep layer, with the difference between the highest and lowest values being only 2.90 times and 1.48 times. The horizontal distribution of soil organic carbon content and density in Zoige alpine wetland showed obvious spatial heterogeneity. The content and density of soil organic carbon in wetland soil were significantly higher than that in grassland, and both characteristics of the samples with high soil moisture content were significantly higher than those with low soil moisture content. In conclusion, the Zoige alpine wetland soil has a strong carbon sequestration capacity, with high soil water content being an important prerequisite for maintaining soil carbon sequestration function of Zoige alpine wetland. Our results are of great significance to the ecological environment management and sustainable development of alpine wetland.

Variation of soil carbon and nitrogen storage under typical vegetations in Wenshan Nature Reserve.

LI Cong, LYU Jing-hua, LU Mei, YANG Zhi-dong, LIU Pan, REN Yu-lian, DU Fan

2021, 40(11):  3531-3542.  doi:10.13292/j.1000-4890.202110.019

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We explored the changes of soil organic carbon (C) and total nitrogen (N) storage along an altitudinal gradient and its coupling relationship with environmental factors in Wenshan Nature Reserve, to provide basic data for estimating ecosystem C and N fixation potential. Three typical vegetation types along an altitude gradient were selected to examine the distribution of C and N storage along the altitude gradient and soil profile. The principal component reduction analysis was used to explore the impacts of environmental factors (microclimate, vegetation, and soil) on C and N storage along the altitude gradient. The results showed that soil carbon and nitrogen storage of different vegetation types showed a significant increase along the altitude (P<0.05). The storage of C and N peaked in middle-montane humid evergreen broad-leaved forest of high altitude, which increased by 82.81% and 80.98% compared with monsoon evergreen broad-leaved forest in the low altitude. Soil C and N storage decreased with the deepening of soil layers (P<0.05). Compared with 0-10 cm layer, C and N storage in 40-50 cm layer decreased by 54.82% and 55.38%, respectively. Litter  thickness, Simpson index, soil total porosity, capillary porosity, moisture content, and total potassium increased along the altitude, while total phosphorus decreased first and then increased. The values of the above-mentioned variables were 53.29%-666.67% higher in middle-montane humid evergreen broad-leaved forest of higher altitude than that in the monsoon evergreen broad-leaved forest of low altitude. The Margalef index, Shannon index, Pielou index, soil non-capillary porosity, bulk density, temperature, pH and mechanical composition decreased along the altitude, the values of which were 15.97%-59.71% lower in the middle-montane humid evergreen broad-leaved forest of high altitude than in the monsoon evergreen broad-leaved forest of low altitude. Changes of environmental factors along the altitude significantly affected C and N storage (P<0.05). The increases of litter amount, annual precipitation, soil total porosity, capillary porosity, moisture content and total potassium along altitudes had a significant positive effect on C and N storage, while the decreases of plant diversity along the altitude had an extremely significant positive effect on C and N storage. In conclusion, soil C and N storage increased along the altitude in Wenshan Nature Reserve. The vertical distributions of microclimate, soil physicochemical properties and litter  thickness along the altitude are the key factors controlling C and N storage.

Effects of land use types on soil physicochemical properties and aggregates stability in cold region wetland.

DING Jun-nan, YU Shao-peng, SHI Chuan-qi, WANG Hui

2021, 40(11):  3543-3551.  doi:10.13292/j.1000-4890.202111.003

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To understand the effects of land use types on soil physicochemical properties and aggregate stability, we measured soil physicochemical properties, soil enzyme, soil labile carbon content, and aggregate stability under four land use types (secondary forest, shrub meadow, Carex swamp and cropland). The results showed that soil physicochemical properties varied greatly under different land use types, with soil pH being neutral or alkaline. Compared with Carex swamp soil, the electrical conductivity, water content, total nitrogen and alkaline hydrolyzed nitrogen of soils in secondary forest, shrub-meadow and cropland were significantly decreased. In the vertical direction, the available phosphorus content of cropland soil was the highest at the 0-20 cm soil layer. The activities of protease, cellulase, urease and β-glucosidase in Carex swamp soil were significantly higher than those of other land use types. There was no significant difference in nitrate reductase activity between Carexswamp and shrub meadow soil. The total organic carbon, dissolved carbon and microbial biomass carbon of Carex swamps were significantly higher than those of other land use types. The content of readily oxidized carbon in Carex swamp and shrub meadow was significantly higher than that of secondary forest and cropland across different soil depths. Compared with Carex swamp, cropland soil had higher content of small aggregates (<0.25 mm). The MWD and GMD indices of cropland soil decreased slightly compared with those of secondary forest, shrub-meadow, and Carex swamp. In conclusion, land use patterns changed the distribution of soil physicochemical properties in different soil layers of cold region wetlands. The Carex swamp (natural wetland) soil has good aggregate stability. Our results provide theoretical reference for sustainable utilization and protection of wetland soil in cold region.

 The relationship between superparasitism of acorn weevils and physical characteristics of acorns.

LIU Ya-ning, LI Zhi-hong, FANG Lin-xin, WANG Yi, ZHANG Wei, SHU Jin-ping, GEN Xian-sheng, WANG Hao-jie

2021, 40(11):  3552-3560.  doi:10.13292/j.1000-4890.202111.029

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Acorn weevil (Curculio bimaculatus) is a predominant insect pest of acorns, with the damage being closely related with the quality of acorns. Aiming to provide a theoretical basis for the efficient control of acorn weevils and the breeding of resistant oak species, we examined the relationship between the damage from oak weevil superparasitism, the characteristics of Quercus acorns, and the oviposition strategy of acorn weevils in five widespread Quercus species. The difference of acorn size among normal acorns, single-parasitized acorns, and superparasitized acorns was analyzed by one-way ANOVA (LSD). The difference of larval weight in single-parasitized and superparasitized acorns was compared with ttest. The effect of acorn characteristics on the oviposition preference of adult acorn weevil was analyzed with linear regression model. The results showed that the pericarp thickness of the normal acorns was significantly thicker than that of the damaged acorns by weevils for all the five Quercusspecies (P<0.05). The linear regression model showed that the superparasitic rate was significantly correlated with length, diameter, and volume of the Quercusacorns (P<0.05). There was no significant difference in larval weight between the single-parasitized and superparasitized acorns, as well as the weight of the first and later larvae emerging from the superparasitized acorns (P>0.05). The female C. bimaculatus adults preferred acorns with larger size and thinner pericarp. Although superparasitism increased the number of larvae in a single acorn, the quality of larvae was not affected. These results indicated that female weevils prefer ovipositing on larger acorns to reduce the negative effects of superparasitism. Superparasitism is a behavioral adaptation strategy for acorn weevils.

Responses of soil pH, nutrients, and enzyme activities to interaction between pruned tea branches and soybean under pot culture.

GUO Bin, GAO Shui-lian, WANG Miao-miao, HU Yun-fei, XIANG Ping, ZHU Qiu-fang, Tukhvatshin Marat, LIN Jin-ke

2021, 40(11):  3561-3569.  doi:10.13292/j.1000-4890.202111.035

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To develop a new technology mode of reducing chemical fertilizers and increasing their efficiency in tea garden, a pot experiment was conducted with four treatments: mulching of pruned tea branches (T1), monoculture soybean (T2), mulching of pruned tea branches and interplanting soybean (T3), and control (CK). We examined the contents of total phosphorus (TP), available phosphorus (AP), total potassium (TK), available potassium (AK), total nitrogen (TN), alkalihydrolyzable nitrogen (AN), organic matter, pH and the activity of urease, cellulase, sucrase, catalase, acid phosphatase, aiming to explore the responses of nutrients and enzyme activities in potted tea garden soil under the interaction of mulching pruned tea branches and interplanting soybean. The results showed that the concentrations of soil TP, AP, AK, and activities of various enzymes had significant response to the interaction between mulching of pruned tea branches and interplanting soybean. The contents of TN and AN in T3 were higher than those in T1 and T2. Organic matter content and soil pH of T3 increased by 53.92% and 2.44% compared with T1, and by 25.60% and 6.03% compared with T2, respectively. The activity of sucrase and urease had similar response, showing T3 > T1 > T2 > CK, with the difference between T3 and other treatments being significant. The activities of cellulase and acid phosphatase under T3 were higher than those of other treatments. PCA results showed that T3 and CK were close to the origin of PC2 and had opposite scores on PC1; T1 and T2 were close to the origin of PC1, and had opposite scores on PC2. There was a strong correlation between phosphorus and potassium concentrations, while organic matter and nitrogen content were closely related to enzyme activity. Soil pH value was significantly positively correlated with the activities of cellulase, urease, sucrase, catalase, and the concentrations of TN and organic matter. Under the condition of pot culture, mulching of pruned tea branches and interplanting soybean had interactive effects on soil nutrient and enzyme activity, which could increase the content of nitrogen and organic matter in tea garden soil, improve soil enzyme activity, and alleviate soil acidification, providing a scientific basis for the new technology of reducing fertilizer application and increasing fertilizer efficiency in tea garden.

Effect of endophytic fungi infection on the growth of Leymus chinensis under benomyl treatment.

LIU Hui, CUI Guang-jie, LI Ming-ming, ZHU Yuan-gang, ZHANG Xiu-ling

2021, 40(11):  3570-3576.  doi:10.13292/j.1000-4890.202111.001

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Dual infection of host plants by Epichlo endophytes and AMF occurs in natural and agricultural ecosystems. Previous studies have focused largely on the effects of endophytes and a single artificial inoculation of AMF on the growth of hosts. However, few studies have investigated the interactive effects between endophytes and AMF on host grasses in natural habitats. In this study, we used benomyl, a specific inhibitor of AMF, manipulating AMF presence or not, to determine the effects of endophytes and/or AMF on the growth of Leymus chinensis. We conducted a pot experiment under two endophyte infection statuses (endophyteinfected, E+; endophytefree, E) and three benomyl addition levels (B0, control; B1, 0.6 g·L^-1 benomyl; B2, 1.2 g·L^-1 benomyl), using L. chinensis as a model. The results showed that endophyte infection significantly increased AMF colonization rate and spore density, and significantly increased tiller numbers, fresh leaf numbers, shoot and root biomass of L. chinensis. The colonization rate and spore density of AMF were significantly reduced by benomyl, especially under the B2 treatment, and the growth advantage of E+ relative to EL. chinensis disappeared under the B2 treatment.

Correlation between photosynthetic chilling resistance and drought tolerance in sugarcane.

WANG Hai-ling, ZHANG Ya-fang, DUAN Wei-xing, QIU Li-hang, ZHU Jun-jie

2021, 40(11):  3577-3584.  doi:10.13292/j.1000-4890.202111.025

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We assessed the correlation between photosynthetic chilling resistance and drought resistance in sugarcane (Saccharum officinarum) with 671 varieties collected from China and abroad. The predawn potential maximum photochemical efficiency (F_v/F_m) of the functionally mature leaves was measured at the predawn of extreme chilling. Furthermore, 34 important varieties were selected for the measurement of leaf F_v/F_m and photosynthetic gas exchange during the common chill season and during extended severe droughts. The results showed that, under extreme chilling condition, 97.5% of the examined varieties significantly suffered from chilling stress but only 1% of which almost completely lost their photosynthetic ability. Among the 34 important varieties, F_v/F_m under the extreme chilling condition, the F_v/F_m surveyed from the common chilling condition, the net photosynthetic rate (P_n), stomatal conductance (G_s) and transpiration rate (E) assessed under extended severe drought were positively correlated. However, the correlations between intrinsic water use efficiency (WUE_i), shortterm water use efficiency (WUE) and intercellular CO₂ concentration (C_i) were not statistically significant. Besides, the F_v/F_m measured under common chilling and under extended severe drought was not significantly correlated with photosynthetic gas exchange parameters measured during extreme chilling. Neither F_v/F_m nor P_n correlated with the sugarcane juice brix under prolonged drought. Our results suggest that sugarcane was generally sensitive to chilling stress. Compared with common chilling and severe drought, extreme chilling could better reflect the photosynthetic potentials of sugarcane. Such potential is positively correlated with photosynthetic carbon assimilation capacity under normal environment and drought condition.

Effects of microtopography on plant biomass and the distribution of both soil water and salinity in coastal saline-alkali  land.

HE Wen-jun, HAN Guang-xuan, YAN Kun, GUAN Bo, WANG Guang-mei, LU Feng, ZHOU Ying-feng, ZHANG Le-le, ZHOU Li

2021, 40(11):  3585-3597.  doi:10.13292/j.1000-4890.202111.002

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Microtopography can change the water-salt distribution pattern and plant growth in coastal saline-alkali soils, and thus realize the efficient utilization and sustainable development of coastal saline-alkali lands. Using the method of sampling lines, we investigated soil water content, soil electric conductivity, and plant biomass at different elevations along the slope of coastal saline-alkali land, and analyzed the factors influencing plant biomass and root-shoot ratio. The results showed that elevation significantly affected soil water content, soil electric conductivity, and pH. Water content and pH across various soil layers tended to decrease with increasing elevation, while soil electric conductivity of topsoil tended to increase. The profile distribution of soil salinity showed a phenomenon of “surface accumulation”, while soil water showed a trend of “bottom layer”. Suaeda salsa and Phragmites australis were the dominant species on the saline slopes. Aboveground biomass per individual plant of both species positively correlated with soil electric conductivity and negatively correlated with soil pH. As the elevation increased, belowground biomass and root/shoot ratio showed a downward trend, while aboveground biomass showed an upward trend. Soil water content and pH together accounted for 68% of the variation of rootshoot ratio. Therefore, ecological restoration and high-efficiency utilization model in coastal saline-alkali land based on microtopography breaks through the traditional concept of saline-alkali land management and utilization, and help realize high-efficient and comprehensive utilization of coastal saline-alkali land.

Effects of nitrogen application rate on soil water use and yield of dryland wheat under furrow sowing in drought year.

WANG Zhi-xin, SUN Min, REN Ai-xia, LIN Wen, ZHAO Qing-ling, ZHANG Rong-rong, LI Lei, HAO Rui-xuan, HAN Xu-yang, GAO Zhi-qiang

2021, 40(11):  3598-3607. 

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To clarify the drought resistance and stable yield effect of different sowing methods, we examined the effects of different sowing methods (furrow sowing, wide space sowing, and drilling sowing) and different nitrogen application rates (N150: 150 kg·hm^-2; N210: 210 kg·hm^-2) on soil water content, yield formation, and water use efficiency in dryland wheat based on a field experiment in Wenxi County Dryland Wheat Experimental Base in Shanxi Province during 2018-2019 (drought year). The results showed that under furrow sowing and wide space sowing, 0-200 cm soil water storage of wintering and jointing stages was increased, total water consumption was significantly increased by 10-19 mm; 1000grain weight of 5-35 days after anthesis, spike length, spikelet number, and percentage of fertile spikelets were increased; spike number was increased by 5%-17%, grains per spike was increased by 2%-6% and 1000grain weight by 5%-8%, which ultimately significantly increased yield by 12%-31% and water use efficiency by 9%-25%. Furrow sowing performed better than wide space sowing. In addition, compared with N210, N150 reduced water consumption from sowing to anthesis stage but increased that after anthesis; it also significantly increased spike number, yield, and water use efficiency. Compared with drilling sowing, the yield-increase effect of water consumption for furrow sowing and wide space sowing was 30-46 kg·hm^-2·mm^-1. Compared to N210, the yield-increase effect of water consumption for N150 reached 25-45 kg·hm^-2·mm^-1. In conclusion, in the drought year, furrow sowing in dryland wheat fields is conducive to accumulate soil water to jointing stage, reducing water consumption in the early growth stage and increasing water consumption in the mid-late growth stages, which would increase effective tiller number, mainly by increasing spike number and optimizing spike traits to increase yield and efficiency. Such effect is better under N150.

Comparison of soil microbial community structure under different continuous cropping patterns of self-rooted and grafted seedlings of selenium-rich sand melon in artificial sand-covered soil.

LI Jing-yu, ZHANG Xiao-chong, TIAN Xing-guo, ZHANG Xiu

2021, 40(11):  3608-3619.  doi:10.13292/j.1000-4890.202111.009

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The sustainable development of agriculture in arid and semiarid areas faces both drought stress and the negative impacts of continuous cropping. In the arid area of central Ningxia, artificial sand-covered soil provides favorable conditions for planting selenium-rich sand melon. However, long-term continuous cropping has led to the death of selfrooted seedlings in large areas, which can only be alleviated by grafting. There is a critical need for in depth understanding of the effects of different continuous cropping patterns on the structure of soil microbial community. In this study, the bacterial and fungal community structure of the artificial sandy layer and soil layer under different continuous cropping patterns were analyzed by Illumina MiSeqsequencing technology. The results showed that continuous cropping patterns and different soil layers significantly affected bacterial and fungal community structures. The genera with significant changes in the bacterial community of soil layers in the cropping mode S3 (self-rooted seedlings with continuous cropping for 11 years + sand replacement for 2 years + grafted seedlings with continuous cropping for 3 years) and S4 (selfrooted seedlings with continuous cropping for 12 years + grafted seedlings with continuous cropping for 4 years) included Streptomyces, Gaiella, Ensifer,Nordella, and Mesorhizobium; the genera with significant changes in fungal community structure mainly included Fusarium, Mortierella,Neocosmospora, Setophoma, Cladosporium, Chrysosporium,Periconia, Penicillium, and Sarocladium. Neocosmospora, Chrysosporium, and Lectera were enriched in the soil layer of S4 under continuous cropping, especiallyFusarium and Paracylindrocarpon. The relative abundance of Fusarium in S4 was significantly higher than that in S3. These results provide scientific data related to the imbalance in soil microbial community structure caused by different continuous cropping patterns.

Effects of spraying NaHS at different growth stages on osmotic adjustment substance and antioxidant activity in leaves of naked oat under salinealkali stress.

LIU Jian-xin, LIU Rui-rui, LIU Xiu-li, JIA Hai-yan, BU Ting, LI Na

2021, 40(11):  3620-3632.  doi:10.13292/j.1000-4890.202111.027

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In order to clarify the optimal application period and appropriate concentration of hydrogen sulfide (H₂S), we sprayed H₂S donor sodium hydrosulfide (NaHS) solution (0, 25, 50, 100, 200 and 400 μmol·L^-1) at seedling, jointing, heading, flowering and filling stages of soil potted naked oats to examine the effects of H₂S on the content of osmotic adjustment substance and the antioxidant activity in leaves under salt-alkali mixed stress (NaCl, Na₂SO₄, NaHCO₃, Na₂CO₃ molar ratio is 12∶8∶9∶1). The results showed that spraying period, NaHS concentration, and their interaction significantly promoted or inhibited the content of osmotic adjustment substance and the antioxidant activity. Compared with non-spraying NaHS, spraying 50 and 200 μmol·L^-1 NaHS at the seedling stage significantly increased the scavenging activity of ABTS·⁺ and the antioxidant activity of FRAP; and spraying 400 μmol·L^-1 NaHS performed best in increasing the total phenol content, scavenging activity of O₂^-_· and total reducing activity. Spraying 50, 100, and 400 μmol·L^-1 NaHS at the jointing stage significantly increased the content of soluble protein, flavonoids, and proline by 30.43%, 31.44%, and 258.59%, respectively. Spraying 50, 100, and 400 μmol·L^-1 NaHS at the heading stage significantly increased the content of proanthocyanidins, soluble sugars and free amino acids by 150.57%, 42.71%, and 197.93%, respectively. Spraying 100 μmol·L^-1 NaHS at the flowering stage significantly increased the scavenging activity of  DPPH· by 93.98%, with the greatest magnitude of enhancement. Spraying 400 and 25 μmol·L^-1 NaHS at the grouting period had the strongest effect on increasing the K⁺ content and K⁺/Na⁺. The interaction between spraying period and NaHS concentration had no significant or negative effect on organic acid content and the scavenging activity of ·OH in leaves. Using membership function analysis to comprehensively evaluate the effects of spraying NaHS at different periods on the osmotic adjustment and antioxidant activity of naked oat leaves showed that the comprehensive evaluation value of spraying 400 μmol·L^-1 NaHS at the jointing and heading stages was significantly higher than that of other concentrations at other periods. These results indicated that exogenous H₂S can alleviate the saltalkali stress of naked oat by improving osmotic regulation and antioxidant activity, with the best performance of spraying 400 μmol·L^-1 NaHS at the jointing-heading stage.

Effects of stem rust infection on photosynthetic characteristics of oats.

HAN Yu-ting, MI Jun-zhen, CHEN Xiao-jing, XU Zhong-shan, LIU Jing-Hui, XUE Guo-xing

2021, 40(11):  3633-3639.  doi:10.13292/j.1000-4890.202111.037

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In order to understand the effects of stem rust on the photosynthetic characteristics of oat leaves, we selected four oat varieties (sensitive varieties Bayou 1 and Mengyan 1; insensitive varieties Bayou 18 and Baiyan 5) to examine the changes of chlorophyll content and photosynthetic parameters in oat leaves 1, 3, 5, 7 and 9 days after inoculation with stem rust fungi. The results showed that net photosynthetic rate of oat leaves increased first and then decreased after inoculation, and that the sensitive varieties increased earlier than insensitive varieties. After being inoculated with stem rust fungi for three days, leaf net photosynthetic rates of insensitive varieties were significantly increased by 20.2% and 17.9% (P<0.05). After being inoculated for five days, except for intercellular CO₂ concentration, the photosynthetic parameters of sensitive and insensitive varieties were significantly decreased. Insensitive varieties can improve plant resistance by maintaining higher net photosynthetic rate, stomatal conductance, and transpiration rate, and lower intercellular CO₂ concentration.

Effects of spring irrigation frequency on plant nitrogen translocation and yield of winter wheat under wide-space sowing.

WANG Pei-ru, YIN Xue-bin, ZHONG Rong, REN Ai-xia, LIN Wen, SUN Min, GAO Zhi-qiang

2021, 40(11):  3640-3649.  doi:10.13292/j.1000-4890.202111.028

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In order to clarify the water saving mechanism of widespace sowing (WS) winter wheat, a field experiment was carried out at the Wenxi Experimental Demonstration Base of Shanxi Agricultural University from 2017 to 2018. We examined the effects of irrigation frequency \[no irrigation in spring (W0), onetime spring irrigation (W1, jointing water), spring irrigation twice (W2, jointing water, flowering water)\] and sowing pattern \[conventional drilling sowing (DS) and WS\] on soil water consumption, plant nitrogen translocation, yield and benefits of winter wheat. The results showed that, compared with no irrigation in spring, W1 and W2 significantly increased soil water consumption and water consumption intensity at sowing-jointing stage and jointing-anthesis stage, significantly increased nitrogen accumulation at jointing, booting and anthesis stages, and increased pre-anthesis nitrogen translocation, nitrogen accumulation after anthesis and contribution to the grain, significantly increase yield and their components, water use efficiency (WUE) and nitrogen use efficiency (NUE). Compared with W2, W1 reduced soil water consumption and water consumption intensity at anthesis-maturity stage, and significantly increased the contribution of pre-anthesis nitrogen translocation to grains, and the contribution of leaf translocation transfer to the grains; significantly reduced grain number per spike and 1000-grain weight, reduced the yield (but insignificant). Meanwhile, W1 significantly improved WUE by 4%-8% and NUE by 5% under the condition of WS, significantly reduced soil water consumption and water consumption intensity of anthesismaturity stage compared with DS, and increased pre-anthesis nitrogen translocation amount, nitrogen accumulation amount after anthesis and their contribution to grains, and significantly increased grain number per spike, yield, and WUE. Under the conditions of different irrigation frequencies and sowing methods, yield was closely related to nitrogen translocation amount of the stem+sheath, spike+glume before anthesis, and nitrogen accumulation after anthesis. The WUE and NUE were more closely related to the nitrogen translocation amount of the stem+sheath. Compared with irrigation at both jointing and flowering stages, irrigation at jointing reduced post-anthesis soil water consumption and increased preanthesis translocation of plant nitrogen to grains, reduced the number of grains per ear and 1000-grain weight, but yield decline was not obvious, WUE and NUE were improved, and with supporting of wide space sowing, increased production by 16%-48%, income by 39%-76%, and output-input ratio by 22%.

Occurrence and function of nodal roots belonging to infertile tillers in winter wheat (Triticum aestivum L.).

XU Li-li, YANG Xi-wen, ZHOU Su-mei, SONG Miao, DENG Yong-xing, YANG Yi-chen, GUO Fang-fang, FU Jin-zhou, HE De-xian

2021, 40(11):  3650-3659.  doi:10.13292/j.1000-4890.202111.034

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It is a common phenomenon that an infertile tiller dies away but its nodal roots survive during wheat growth and development. It is important to study the occurrence, growth, and function of nodal roots belonging to infertile tillers for both wheat ecophysiological theory and high-yield & highefficiency cultivation practice. We explored the occurrence, growth, and vigor of nodal roots belonging to infertile tillers and their relationships with grain yield, quality, and nitrogen use efficiency of the whole plant under different nitrogen application rates. The results showed that nodal roots belonging to infertile tillers occurred from growth recovering to jointing stage, and ended to develop during grain-filling stage, with the number of 7-15 roots per plant. From anthesis to grain-filling and mature stages, nodal roots belonging to infertile tillers increased first and then decreased, with a change ranging from 1 to 3 per plant. Physiological vigor of nodal roots belonging to infertile tillers was weaker than that belonging to fertile tillers, and the former gradually decreased with growth. The number of nodal roots belonging to infertile tillers was positively correlated with ears per unit area, and negatively correlated with grains per ear and grain yield. There was a positive correlation between physiological vigor of nodal roots belonging to infertile tillers and wheat yield and its components. As for grain quality, both the number and vigor of nodal roots belonging to infertile tillers were positively correlated with the contents of protein and soluble sugars of grains. The number and vigor of nodal roots belonging to infertile tillers in late growing period were positively correlated with partial factor productivity of applied nitrogen and nitrogen uptake efficiency. In conclusion, appropriate regulation and control of nodal roots belonging to infertile tillers in practice would be important for grain yield and quality formation of winter wheat.

Effects of waterlogging, low illumination, and their synergism on the growth and development of wheat.

JIANG Min, LIN Dan, SHI Chun-lin, SUN Bin, Xuan Shou-li, XUE Chang-ying

2021, 40(11):  3660-3672.  doi:10.13292/j.1000-4890.202111.032

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Agrometeorological disaster is one of the main factors restricting high yield and quality of crops. The waterlogging and low illumination caused by continuous overcast and rainy weather in the middle and lower reaches of the Yangtze River seriously influence the growth and development of wheat. To explore the effects of continuous overcast and rainy weather on the growth and development of wheat, a controlled experiment with three stress types (waterlogging, low illumination, waterlogging + low illumination) and three durations (5, 10 and 15 d) during elongation and booting stages of winter wheat was conducted in Jiangsu Academy of Agricultural Sciences, with cultivars Ningmai 13 and Yangmai 23 as experimental materials. We measured plant height, tiller number, chlorophyll content and photosynthetic rate of wheat leaf blades during stress process and postdisaster recovery tests. The results showed that different stress types delayed the development of both cultivars, with greatest synergistic effects of waterlogging and low illumination at the jointing stage. For all different stress types at booting stage, the delay of filling and maturity process became more obvious with the extension of treatment time. Plant height was affected by the stress at jointing stage and booting stage. Waterlogging and waterlogging + low illumination treatments significantly affected plant height, while low illumination alone had a weak effect. A stronger effect on plant height was found at booting stage stress than at jointing stage. Under waterlogging and waterlogging + low illumination stress in different growth stages, the chlorophyll content of wheat decreased in varying degrees, but the response to low illumination was variable. When low illumination alone was applied for five days at jointing stage, the chlorophyll content was higher than that of the control, but decreased to the lower level of the control with the increased stress duration. The chlorophyll content of wheat under low illumination stress at booting stage was higher than that of the control. The effects of different stresses on the photosynthetic rate of wheat were as follows: the longer the jointing and booting stage was stressed by waterlogging or low illumination, the greater the decline of photosynthetic rate. The photosynthetic rate at jointing stage was the most sensitive to the synergistic effect of waterlogging and low illumination, and the change of the photosynthetic rate at booting stage was the most obvious under single waterlogging treatment. The photosynthetic rate of wheat at jointing stage could rapidly recover to a normal level under different treatments for five days. The longer the treatment duration was, the more inhibited the photosynthetic rate of wheat and the slower the recovery. Waterlogging + low illumination had the greatest impact on the recovery process. When the waterlogging lasted for more than 10 days or waterlogging + low illumination for more than 15 days at booting stage, the photosynthetic rate could not recover to CK level, but for low illumination treatment, the photosynthetic rate could recover under different stress duration. Overall, our results can be used to evaluate the damage caused by waterlogging and low illumination, which improve the applicability of wheat growth model under agrometeorological disasters.

Temporal variation of bird banding numbers at north slope of Xiaoqinling of Henan Province.

ZHANG Kai, LI Dong-wei, CHEN Li-xia, ZHANG Ya-fang, YAO Guan-zhong, HAN Jun-wang, ZHANG Guo-gang

2021, 40(11):  3673-3682.  doi:10.13292/j.1000-4890.202111.023

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Bird banding is a basic method to study the population movement pattern of birds, and also an effective method to monitor bird population dynamics. In this study, we analyzed the bird banding data at north slope of Xiaoqinling of Henan Province, aiming to provide basic data for its protection and management. The bird banding was conducted at Yawu Mountain located in southwest of Xiaoqinling Nature Reserve from September 20 to October 30 in 2007-2016, and bird species banded were mainly dominated by Passeriformes. The change trend of the top 10 abundant species, and the abundance and species numbers of Palearctic and Oriental Realm were analyzed using the general linear regression analysis. A total of 4131 birds from 182 species were banded. The families Muscicapidae and Fringillidae were banded as the most abundant. The abundance of bird species of Oriental Realm had been increasing from 2007 to 2016, which reflects species dispersal from the south to the north slope of Xiaoqinlin Mountains. The increases in the number of bird banding were mainly related to the better habitats of Yawu Mountain, which has the original and unexploited landscape, attracting more birds from south slope. It is suggested that the Xiaoqinling Nature Reserve should organize professionals to carry out special investigation projects of bird resources in the future, and conduct a comprehensive and systematic investigation of bird resources combining the bird banding.

Population dynamics of Oriental Storks (Ciconia boyciana) at Xingkai Lake in China.

LIU Hua-jin, CHEN Li-xia, LIU Yu-lin, YANG Pei-yu, LU Jun, ZHANG Guo-gang

2021, 40(11):  3683-3690. 

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The survey of population size and distribution is fundamental for population dynamics research, and is also key to determining and understanding the threats to various species. As an important migration corridor and breeding site for migratory waterbirds in northeast Asia, Xingkai Lake in Heilongjiang Province is a significant wetland for the conservation of Oriental Storks (Ciconia boyciana). In this study, we analyzed changes of stork population abundance at Xingkai Lake in the migration and breeding seasons from 2002 to 2018, and examined the effects of the reintroduction of artificial nests on stork population dynamics and the driving factors. Our results showed that the number of storks increased significantly in spring  (R²=0.641, P=0.000) and the breeding season (R²=0.866, P=0.000), and that in autumn fluctuated greatly among different years. There was a significant positive correlation between the numbers of storks in spring and summer (R=0.701,P=0.002), indicating that the high population number in spring resulted in high number in summer. The nests of Oriental Storks at Xingkai Lake were mainly distributed in Longwang Temple (84.16%), Dongbei Paozi (12.87%), oxidation pond (1.98%) and Qing-shan Reservoir (0.99%). From 2002 to 2018, the number of successful nests, including natural (R²=0.514, P=0.001) and artificial nests (R²=0.823, P=0.000), significantly increased. The increases in stork population number at Xingkai Lake were mainly affected by the increased overall population, installing artificial nests, climate change, food abundance, habitat suitability, and human disturbances. Our results would contribute to the understanding of the population dynamics of Oriental Storks and provide a scientific basis for the development of conservation and management strategy specific to this species at Xingkai Lake.

Effects of artificial landscapes on summer bird communities in the mountainous area of southern Anhui Province.

WANG Xue, ZHU Guang, CUI Peng, MA Hao-hao, LI Chun-lin

2021, 40(11):  3691-3700.  doi:10.13292/j.1000-4890.202111.017

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Understanding the effects of anthropogenic landscapes on birds would inform conservation policy. In August 2019, we used line transects to survey bird communities in four habitats, i.e., cropland, village, forest, and highway, in the mountainous area of southern Anhui Province. In total, we recorded 4432 birds, belonging to 86 species, 39 families, and 13 orders. The mean bird abundance decreased from village to cropland, highway, and forest. The mean species richness decreased from cropland to village, highway, and forest, while the accumulated species richness decreased from cropland to forest, village, and highway. The Shannon diversity index in cropland was the highest, while the Pielou evenness index in cropland was only slightly lower than that in forest. These indices in village were the lowest. There were significant differences in bird species composition among the four habitats. The Bray-Curtis dissimilarity index was the highest between forest and village, followed by that between forest and cropland, whereas it was the lowest between highway and cropland. The occurrences of 14 species were significantly correlated with the habitat types. These results indicated that there were significant differences in bird communities among the different landscapes in the mountainous area of southern Anhui. All habitats should be conserved to protect the bird diversity in this region. Among those habitats, croplands were the most preferred for birds. However, human disturbance was more intense in croplands than in other habitats and the value of biodiversity conservation was often neglected. Therefore, the protection of cropland birds should be strengthened.

Effect of lentinan on antioxidant function of loach (Misgurnus anguillicaudatus) under ammonia nitrogen stress.

LIU Cheng-rong, LIU Li-xiang

2021, 40(11):  3701-3710.  doi:10.13292/j.1000-4890.202111.038

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As an immunopotentiator, polysaccharose can enhance the adaptation of animals to environmental stresses. The effects of polysaccharose on the antioxidant function of Misgurnus anguillicaudatus under ammonia stress are unclear. In this study, Misgurnus anguillicaudatus was exposed to water containing ammonia concentration of 0, 100, 200, and 300 mg·L^-1 for 40 days, respectively. The experiment was divided into test group and control group. Misgurnus anguillicaudatus in test group was fed with the diet containing lentinan with a concentration of1.0mg·g^-1, while that in control group was fed with the diet without lentinan. On 0, 5, 10, 15, 20, 25, 30, 35 and 40 d of the experiment, we measured the activities of superoxide dismutase (SOD), catalase (CAT), acid phosphatase (ACP) and alkaline phosphatase (ALP) in liver and muscle of Misgurnus anguillicaudatus, to investigate the effects of lentinan on the antioxidant function of Misgurnus anguillicaudatus under ammonia nitrogen stress. The results showed that the activities of SOD, CAT, ACP and ALP in liver and CAT in muscle of the 100 mg·L^-1 test group were significantly higher than those in control group (P<0.05). On the 30th day, the activities of SOD, CAT in muscle and liver of 100 mg·L^-1 test group reached the highest values, which were (26.0±2.3), (39.0±3.1), (37.0±3.8) and (45.0±3.6) U·g^-1 respectively. On the 35th day, the activities of ACP and ALP in muscle and ACP in liver in the 200 mg·L^-1 test group and the activity of ALP in liver in the 100 mg·L^-1 test group reached the highest values, with (23.0±2.1), (39.0±4.1), (33.0±2.4) and (46.0±1.8) U·g^-1 respectively. Theseresults indicate that lentinan can improve the antioxidant capacity of Misgurnus anguillicaudatus under ammonia stress.

Effects of freeze-thaw cycles on cadmium speciation in soils during stabilization remediation of biochar.

WANG Yue, SUN Jian-ping, SUN Li-zong, JIA Chun-yun, TAI Pei-dong

2021, 40(11):  3711-3719.  doi:10.13292/j.1000-4890.202111.004

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Freeze-thawing is an important process in northern cold region of China, and it is an important factor affecting the properties of soil and materials for stabilizing heavy metals. In this study, a test of freeze-thaw cycles was carried out to examine the effects of freeze-thaw on the transformations of cadmium (Cd) form during the remediation of biochar for contaminated soils, with the underlying mechanism being analyzed. The results showed that, in the remediation process of biochar, after 16 cycles of freezing and thawing, the contents of weak acid extracted form Cd, reducible form Cd, and oxidizable form Cd in soil increased by 16.07%, 6.67%, and 15.37%, respectively, while the residue content remained stable. On the whole, the increasing content of available Cd will pose serious ecological risks. Two major reasons were responsible for such alterations. Firstly, without biochar addition, the content of weak acid extracted form Cd and reducible form Cd in soil increased by 11.74% and 13.53%, respectively. Soil capillary porosity increased from 41.72% to 57.63%, soil pH decreased slightly, and the content of soil dissolved organic carbon increased significantly by 15.38% firstly and then decreased by 10.17% over time. The combined effects of the abovementioned factors increased weak acid extracted and reducible form Cd in soil Cd system. Secondly, during the freeze-thaw process, the tubular structure and integrity of biochar were destroyed, the stretching vibrational absorptions of hydroxyl-OH, carbon-hydrogen bond C-H, and aromatic composition were weakened and shifted, and the carbonate composition were decreased, which resulted in the decrease of adsorption sites and adsorption capacity of biochar for Cd.

Heavy metal concentrations in aquatic products and health risk of human exposure in Qingdao City.

LI Yuan, WANG Chuan, FENG Lin, DING Li, YANG Shao-chen, LI Jun, LI Ping

2021, 40(11):  3720-3729.  doi:10.13292/j.1000-4890.202110.001

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We investigated the pollution status of heavy metals in aquatic products and human exposure, and explored the influence of aquatic products consumption on the concentrations of heavy metals in residents’ hair in Qingdao. A total of 156 aquatic products samples with 19 common species and 130 human hair samples were collected in Qingdao. The concentrations of Cd, As, Pb, Cr, Cu, and Zn in aquatic products and hair samples were measured by ICP-MS. The median values of Cd, As, Pb, Cr, Cu, and Zn concentrations in 156 aquatic products samples were 0.006, 1.18, 0.015, 0.253, 2.06, and 11.8 mg·kg^-1, respectively. The concentrations of heavy metals varied across different kinds of aquatic products. The averages of Cd concentrations in scallops and shrimps were 2.45 and 1.14 mg·kg^-1, respectively, with 50% of scallop samples (6/12) and 100% of shrimps samples (10/10) exceeding China’s national food safety standard. The median values of Cd, As, Pb, Cr, Cu, and Zn concentrations in residents’ hair samples were 0.0231, 0.0518, 0.988, 0.595, 7.81, and 155 mg·kg^-1, respectively, with the exceeding rates being 0, 1.5%, 2.3%, 6.9%, 2.3% and 28.4% compared with national recommended values for hair heavy metals, respectively. The hair Zn concentrations in residents with high frequency of fish consumption were significantly elevated. The hair Pb, As, and Zn concentrations changed significantly with age. The hair As concentration of male was significantly higher than that of female (P<0.01), and hair Zn concentration of female was significantly higher than that of male (P<0.01). Our results indicated that the Cd concentrations in scallops and shrimps in Qingdao were relatively high, which should be restricted for consumption. The average Zn concentration in oyster was 107 mg·kg^-1, which should be limited for consumption. The main influencing factors of heavy metals concentrations in human hair include age, gender, and the consumption frequency of aquatic products. About 28% of hair Zn concentrations exceeded the notional recommended value, indicating that residents in Qingdao had potential risks of Zn exposure. Our results provide important reference for dietary guidance of aquatic products and risk control of heavy metal exposure in Qingdao.

Effects of nitrogen deposition on soil microbes, enzyme activities, fine root production and turnover in forest ecosystems: A review.

GUO Chao, WANG Lin-jiao

2021, 40(11):  3730-3741.  doi:10.13292/j.1000-4890.202111.010

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Global nitrogen deposition is generally increasing year by year, with substantial effects on carbon and nitrogen cycling in forest ecosystems. Soil microbes, soil enzymes, and fine roots are important belowground components, playing crucial roles in the material circulation and energy flow of forest ecosystems. Their responses to nitrogen deposition have become a hot topic in the research field of global climate changes. Here, we summarized the effects of nitrogen deposition on soil microbes, enzyme activities, fine root production and turnover in forest ecosystems. Results showed that nitrogen deposition caused soil acidification, preserved soil nutrients, and changed the distribution pattern of belowground carbon and nitrogen. Effects of nitrogen deposition on the structures of soil microbial communities were mainly reflected in the increase or no change of soil bacteria/fungi ratio and changes in the relative abundance of soil microbes. Effects of nitrogen deposition on the functions of soil microbes were mainly reflected in promoting or inhibiting soil microbial respiration, changing nitrogenfixation groups, and reducing nitrogen use rate of soil substrate, and were significantly affected by soil pH, soil available nutrients, and the time of nitrogen application. Nitrogen deposition could promote or inhibit soil enzyme activities, which were significantly affected by soil depth, soil pH, and soil limiting elements (such as carbon, nitrogen and phosphorus). Along with increasing nitrogen deposition, fine root biomass decreased, fine root turnover speeded up or slowed down, fine root decomposition shifted from stimulating to inhibiting, which were significantly affected by soil nutrient availability, soil nitrogen storage, and fine root chemical properties. Focusing on the key scientific issues needed to be solved urgently in this research field, eventually we discussed important directions for future research. This review has great significance for further clarifying the mechanisms underlying the impacts of nitrogen deposition on soil microbes, enzyme activities, and fine root in forest ecosystems, and thus for the protection and rehabilitation of forest ecosystems under the background of increasing nitrogen deposition.

Influence of greening on the diffusion of particulate matters in urban street canyon: A review.

CHEN Xiao-ping, CHEN Shuo, LIU Yan-hong, WU Xiao-gang

2021, 40(11):  3742-3750. 

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Street canyon greening is an important part of urban green infrastructures, playing a critical role in controlling air pollution. Plant type, configuration and structural characteristics could significantly affect the absorption, deposition, and diffusion of particulate matters (PMs) in the street canyon, with consequence on pedestrian health. Optimizing the design of street canyon greening is a research hotspot in multiple disciplines. Here, we summarized the greening parameters, discussed the research methods and regulation mechanism of PMs diffusion by greening in street canyon, and further analyzed the attenuation efficiency of greening to PMs and related affecting factors (street morphology, street direction, building roof form, sky view factor, meteorological factors and emission intensity). Finally, we proposed that further research should focus on the parameterization, multifactor coupling, multi-scale fusion, and the tradeoffs between multiple ecological functions of street canyon greening, which could provide theoretical basis for air quality improvement and greening construction in street canyons.

Effects of low-cost materials on the transport behavior of ΦX174 in soil.

WANG Rui-qi, YANG Li-qiong, ZHUANG Jie, SHI Ya-nan, CHEN Xi-juan

2021, 40(11):  3751-3759.  doi:10.13292/j.1000-4890.202111.005

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Low-cost industrial/agricultural by products and mineral materials have the potential to remove pathogens in soil and water environment. We chose ΦX174 as the target pathogen. Magnesite, calcined magnesite, iron filings, biochar, zeolite, limestone and bauxite were mixed with soils from the top layer at a volume ratio of 1∶9 and filled into the column, respectively. An indoor soil column transport experiment was carried under steadystate saturated conditions to explore the effects of different materials on the transport behavior of soil viruses. Results showed that the removal rate of ΦX174 was in order of calcined magnesite (100.0%) > magnesite (23.3%) > iron filings (16.9%). The removal rates of ΦX174 were less than 15.0% for biochar, zeolite, limestone, and bauxite. The analysis of the changes in the surface crystal structure and phase composition of the materials before and after the experiment showed that the calcined magnesite partially reacts in the experimental solution to form magnesium hydroxide, which changes the surface crystal structure of the material and the chemical conditions of the solution, so that the virus was removed through solid phase adsorption and liquid phase inactivation. Magnesite’s material properties were stable, without any reaction products being formed. Iron filings partially react in the experimental solution to generate iron oxides and hydroxy iron oxides, which increase the virus adsorption sites on the surface of the iron filings. The possible adsorption mechanisms of iron filings and magnesite are electrostatic interaction and hydrophobic interaction. Our results provide a theoretical basis and restoration reference for preventing and controlling pathogenic pollution.

 

Optimization of cotton irrigation schedule under mulch drip irrigation in southern Xinjiang based on DSSAT model.

DU Jiang-tao, ZHANG Nan, GONG Ke-ning, DU Ming-zhi, YANG Ying-pan, WANG Xing-peng

2021, 40(11):  3760-3768.  doi:10.13292/j.1000-4890.202111.030

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To investigate the applicability of the DSSAT model to the drip irrigation under mulch of cotton in southern Xinjiang and find out optimal irrigation schedule, the DSSAT-CROPGRO-Cotton model parameters were calibrated and validated by field measurement data of flowering date, maturity date, yield, and aboveground biomass in 2018 and 2019. The highyielding and watersaving irrigation scheme was obtained by continuously adjusting the irrigation quotas. The results showed that the relative rootmeansquare error (nRMSE) of the CROPGRO-Cotton model was less than 10% for simulating flowering date, maturity date, and cotton yield of cultivar “Xinluzhong 46”, while the nRMSE was less than 20% for the simulation of aboveground biomass. The consistency index (d) of flowering date, maturity date, yield, and aboveground biomass of cotton was greater than 0.85, indicating a good simulation effect of the model. Using meteorological data from 2017 to 2020, the optimal irrigation scheme was obtained, with irrigation volume, yield and wateruse efficiency being accounted for. When the daily difference between the cumulative crop evapotranspiration and precipitation (ET_C-P) of cotton field reaches 25 mm, an irrigation quota of 27 mm is implemented, with 297 mm of irrigation quota in total during whole growing period, which is an optimal irrigation schedule considering both yield and water use efficiency.