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Table of Content

    20 February 2019, Volume 30 Issue 2
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    Special Features of Soil Physics and Ecological Enviornment
    Relationship between soil moisture dynamics, crop growth and precipitation in rain-fed area of the Loess Tableland, China.
    ZHANG Rui, LI Peng-zhan, WANG Li
    2019, 30(2):  359-369.  doi:10.13287/j.1001-9332.201902.015
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    Studying soil water dynamics is critical to agricultural production and ecological environment construction. Based on a 4-year field experiment, we measured soil moisture in both winter wheat and spring corn fields in rain-fed Changwu Tableland of the Loess Plateau from 2012 to 2015, explored soil desiccation and analyzed the effects of soil moisture on crop growth, the effect of precipitation on soil reservoir, and the effect of crop on soil water dynamics. The results showed that the dominant factor for the formation of dried soil layer was yearly precipitation pattern in winter wheat field and was uneven distribution of precipitation among months in each year in spring corn field. Permanent dried soil layer did not occur in both winter wheat and spring corn under the plan-ting system of one crop a year in rain-fed Changwu Tableland. Due to the characteristics of soil water circulation in the Loess Tableland, planting winter wheat was more suitable for this region compared to spring corn. Soil water availability in the Loess Tableland area could ensure the stability of crop yield. Under the influence of precipitation, soil reservoir in winter wheat was consecutively recharged from harvest period to fallow period to seedling period, while from slow consumption period to large consumption period, soil reservoir was consecutively consumed. Soil reservoir in the depth of 0-300 and 300-600 cm was inconsistent. If the maximum root depth was used as sampling depth when measuring soil moisture, evapotranspiration would be overestimated in the fallow period and the seedling period, but would be underestimated in the large consumption period and slow consumption period. This was mainly due to the negative feedbacks of deep soil reservoir. In winter wheat field, transition layer existed and ranged from 140-360 cm. Crop growth at different stages had an effect on soil reservoir. Soil reservoir showed inter-annual regulation effect on the water supply to winter wheat and intra-annual regulation effect on spring corn.
    Comparison of soil organic matter, bulk density and clay content in small watersheds under different ecological managements of Loess Plateau, China.
    HUANG Yan-li, LI Zhan-bin, SU Hui, WANG Shan-shan, LI Yao-lin, LIU Chen-guang
    2019, 30(2):  370-378.  doi:10.13287/j.1001-9332.201902.013
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    To explore the effects of small watersheds with different ecological managements on soil properties, the spatial differences of soil organic matter (SOM), bulk density (BD), and clay content (CC) in the four facets, including slope aspect, slope position, zone, and soil layer, were analyzed between Yangjiagou (YJG, artificial Robinia pseudoacacia forest watershed) and Dongzhuanggou (DZG, closed grassland watershed). The results showed that SOM, BD and CC were 12.78 g·kg-1, 1.24 g·cm-3, 19.2% for YJG and 11.13 g·kg-1, 1.21 g·cm-3, 18.2% for DZG, respectively. The values for YJG were slightly higher than those for DZG, but the difference was insignificant. All indices in the east slope were bigger than those in the west slope. Across different slope positions, the variation of BD was small, SOM and CC showed increasing trends from top to bottom. BD and CC declined downward the watershed, whereas SOM changed in an opposite trend. From the soil surface down to 60 cm soil depth, BD and CC increased and SOM decreased. The spatial sensitivity followed CC > SOM > BD, and the effects of the spatial factors can be ordered as soil layer > zone > slope aspect > slope position. There were significant differences in CC of the upper reaches, BD and CC of the middle reaches between the two basins. The sensitivity of each index to slope position, zone and soil layer in YJG was lower than that in DZG.
    Simulation of soil water dynamics and water productivity of apple trees in different areas of Shaanxi Province, China.
    GUO Fu-xing, CHANG Tian-ran, LIN Yang-yan, WANG Yan-ping, MU Yan
    2019, 30(2):  379-390.  doi:10.13287/j.1001-9332.201902.017
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    Using WinEPIC and partial least squares regression model, we compared the driving factors of water productivity and soil moisture dynamics of several mature apple plantations in Shaanxi from 1981 to 2016. For the hilly and gully region of northern Shaanxi, the residual loess platform region in Weibei, and Guanzhong Plain, the average annual yield of mature apple forests was 16.94, 22.62 and 25.70 t·hm-2, the annual average evapotranspiration was 511.2, 614.9 and 889.88 mm, and the water productivity was 3.81, 3.82 and 3.24 kg·m-3, respectively. In northern Shaanxi and Weibei regions, water stress was the most serious, with the average annual stress days being 54.89 and 28.38 d, respectively. The N-level stress in Guanzhong region was severe, with an average annual stress day of 25.87 d. The largest factor affecting the yield of apple plantations in the northern Shaanxi and northern Weibei regions was the precipitation. The standardized regression coefficients were 0.274 and 0.235, respectively, the amount of N applied had a significant impact on the yield, with regression coefficients of 0.224 and 0.232, respectively. The maximum impact factor in Guanzhong region was the amount of N applied, with a regression coefficient of 0.335, followed by the amount of water supplied and the amount of applied P. The regression coefficients were 0.154 and 0.147, respectively. The dominant factor affecting the water productivity of apple plantations in northern Shaanxi and Weibei was precipitation, and the standardized regression coefficients were 0.238 and 0.194, respectively. The most important impact factors in Guanzhong region were the amount of N applied and the amount of water supplied, and the regression coefficients were 0.182 and 0.178, respectively. During the simulation period, the total water consumption of apple plantations in the northern Shaanxi, Weibei and Guanzhong regions was 1152.17, 1342.95 and 1372.42 mm, respectively. The effective water content decline rates of 2-15 m soil layers were 63.44, 57.08 and 51.41 mm·a-1, respectively. The dry layer of deep soil appeared after 8, 13 and 17 years, and the dry layer was stable to 11 m deep for 18, 21 and 26 years, respectively, suggesting the drying status was severe. The management focus of apple plantations in different regions should be determined by the dominant factors of water productivity.
    Responses of runoff and soil loss from biological soil crustal slope to rainfall intensity under simulated rainfall.
    XIE Shen-qi, GAO Li-qian, ZHAO Yun-ge, GUO Yue-wei
    2019, 30(2):  391-397.  doi:10.13287/j.1001-9332.201902.012
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    Biological soil crust (biocrust) is a common surface cover on the rehabilitated slope land in Hill Loess Plateau. We investigated the responses of runoff and soil loss from biological soil crustal slope to rainfall intensity by using simulated rainfall trial. The results showed that the runoff and soil loss from biocrust slopes increased sharply at the beginning stage of rainfall and then became stable during 10 to 18 min. Compared to bare soil slope, the initial runoff generation time of biological soil crustal slope was significantly increased. The presence of biocrust could significantly decrease runoff and sediment by 21%-78% and 77%-95%, respectively. Rainfall intensities affected soil erosion of biocrust slopes mainly via affecting runoff. The transition from insignificant to significant correlation between runoff and soil loss from biological soil crustal slopes and rainfall intensities was observed with the increases of rainfall intensities. Once the rainfall intensity was higher than 1.5 mm·min-1, there was a significant decrease in the function of biocrust to decrease runoff and soil loss with the increases of rainfall intensities. Our results laid the foundation for the model simulation of runoff and soil loss from biocrust slopes under rainfall conditions.
    Applicability of HYDRUS-1D model in simulating the soil moisture in deep profiles on the Weibei rainfed highland, China.
    LI Bing-bing, WANG Yun-qiang, LI Zhi
    2019, 30(2):  398-404.  doi:10.13287/j.1001-9332.201902.009
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    Soil water balance has been greatly changed with the implementation of ecological restoration in the Loess Plateau. Some hydrological variables, such as deep drainage, can be hardly determined by traditional monitoring methods, and thus need to be analyzed by models. We simulated vertical distribution and time variation of soil moisture within 10 m profiles under a farmland and apple orchard by HYDRUS-1D model, and further evaluated model applicability. Based on observation from September 2011 to October 2013, the spatial and temporal discretization of soil water was simulated with calibrated soil hydraulic parameters. For the calibration and validation periods, HYDRUS-1D performed well with coefficient of determination of 0.65-0.85, model efficiency coefficients of 0.55-0.83, and root mean square errors from 0.01 to 0.02 cm3·cm-3. The simulated soil water contents had similar vertical distribution and temporal variation as the observation, implying that HYDRUS-1D was suitable for simulation of soil hydrology in deep profiles on the Weibei rainfed highland.
    Effect of subsoiling depths on soil physical characters and sugarcane yield.
    LUO Jun, LIN Zhao-li, QUE You-xiong, LI Shi-yan, YAO Kun-cun, JIANG Yong, ZHANG Hua, CHEN Jian-feng
    2019, 30(2):  405-412.  doi:10.13287/j.1001-9332.201902.010
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    We investigated the physical properties of the plough soil and the components of sugarcane yield in the depth of mechanized subsoiling of sugarcane field, along with the clarification on the specific soil location and obstacle factors of subsoiling, with the aim to provide scientific basis for the construction of a good sugarcane cultivation layer and the development of soil improvement strategies. Three depths of subsoiling operation (35, 40 and 45 cm) were set up, with nosubsoiling as control. Soil physical properties, including compactness, bulk density, water content, porosity, three-phase volume ratio, and yield components and cane yield of sugarcane in the fields were investigated. The results showed that subsoiling depth was significantly correlated with the soil structure characteristics and the improvement of sugarcane yield in sugarcane field. Subsoiling broke down the plow bottom, significantly reduced soil compaction, bulk density, and the corresponding penetration resistance and shear strength during mechanical operation, especially for the above factors in 20-30 cm soil layer, with positive consequences for sugarcane yield. Moreover, subsoiling significantly increased the liquid volume rate of the soil layer within 30 cm and soil moisture storage capacity, and thus significantly improved the water index of the 10-30 cm soil layer. The 10-30 cm soil layer was the location for the most significant effect of subsoiling on the improvement of solid volume rate in the plough soil. The effective stem number, plant height, cane yield and sucrose content of sugarcane were significantly promoted by subsoiling. In view of the common equipment level in the sugarcane planting area, we suggested that the operating depth standard of mechanized subsoiling should not be less than 40 cm.
    Effects of ant nesting on the spatiotemporal dynamics of soil easily oxidized organic carbon in Xishuangbanna tropical forests, China.
    LI Shao-hui, WANG Shao-jun, ZHANG Zhe, CHEN Min-kun, CAO Run, CAO Qian-bin, ZUO Qian-qian, WANG Ping
    2019, 30(2):  413-419.  doi:10.13287/j.1001-9332.201902.002
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    Ant nesting can form microhabitat and soil nutrient condition in their nests that is diffe-rent from the surrounding environment, thus having a crucial effect on the variation of soil easily oxidized organic carbon (EOC). In this study, the Mallotus paniculatus communities in Menglun Tropical Botanical Garden of Xishuangbanna, Chinese Academy of Sciences was taken as the research object. We compared the spatiotemporal distribution of soil EOC in ant nests and the refe-rence soils, and analyzed the relationship of the variation in soil EOC to the changes in soil physicochemical properties. The results showed that soil EOC in ant nests and the reference soils had a unimodal change trend with months. The order was ranked as June>September>March>December. The soil EOC decreased with the soil layers. The EOC was higher in 0-5 cm nest soils than in the refe-rence soils, while it was not significantly different in the 5-10 cm and 10-15 cm soil layers. Ant nesting increased soil temperature, soil organic carbon, soil easily oxidized organic carbon, soil microbial biomass carbon, total nitrogen, soil nitrate nitrogen and hydrolysis nitrogen, but reduced the soil water content and bulk density. The impacts of ant nesting on soil ammonium and pH was not significant. The soil organic carbon and microbial biomass carbon had crucial roles in regulating the spatiotemporal variation in EOC in ant nests and the reference soils, whereas the effects of soil temperature, soil water content, total nitrogen and nitrate nitrogen ranked the second. The ant nesting had a crucial effect on the spatiotemporal variations in easily oxidized organic carbon, mainly through changing the microhabitat (e.g., soil temperature and moisture) and soil nutrients (e.g., soil organic carbon and microbial biomass carbon) in Xishuangbanna tropical forests.
    Special Features for 2018 Annual Meeting of Ecological Society of China
    Nutrient and metabolic responses of the leaves of Cunninghamia lanceolata seedlings to warming and reduced precipitation in different seasons
    ZHANG Qiu-fang, LYU Chun-ping, ZHOU Jia-cong, LI Xiao-jie, ZHENG Yong, XIONG De-cheng, CHEN Yue-min, YANG Yu-sheng
    2019, 30(2):  420-428.  doi:10.13287/j.1001-9332.201902.001
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    We examined the effects of warming (+5 ℃) and reduced natural precipitation (-50%) on nutrient status and physiological indices of Cunninghamia lanceolata seedlings during winter and summer in subtropical China. The results showed that seasonal changes in temperature and precipitation caused the seasonal differences in plant nutrient contents and metabolites levels. Contents of carbon, nitrogen, phosphorus, and potassium in leaves in winter were significantly higher than those in summer. In summer, reduced precipitation and warming had no significant effects on antioxidant enzyme activities in C. lanceolata leaves. In winter, superoxide dismutase and peroxidase activities in the leaves significantly decreased with reduced precipitation by 20.7% and 17.8%. Additionally, in winter, warming treatment significantly increased non-enzymatic ascorbic acid content by 132.5%. Carbon content decreased, whereas proline accumulation and nitrogen content increased under stress induced by combined warming and reduced precipitation in winter. However, carbon content increased by 3.3% under the treatment of simultaneous warming and reduced precipitation in summer. In addition, combined warming and reduced precipitation had no significant effects on the antioxidant system irrespective of the season. In conclusion, the adaptation mechanism of C. lanceolata to warming in summer might be different from that in winter. The changes in nutrient contents in C. lanceolata leaves were more sensitive to stress induced by combined warming and reduced precipitation. Nutrient demand and supply and seasonal changes in plant responses under climate change scenarios should be considered for better managing forest plantations and improving plant productivity.
    Characters of ecosystem vulnerability in southwestern China based on vegetation productivity.
    HE Min, WANG He-song, SUN Jian-xin
    2019, 30(2):  429-438.  doi:10.13287/j.1001-9332.201902.006
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    Southwestern China is one of the most important areas for global biodiversity conservation. Under the background of global climate change, the vulnerability of this area has showed an increasing trend. According to the IPCC concept of vulnerability, we calculated the spatial distribution of ecosystem’s vulnerability in southwestern China based on gross primary productivity (GPP) and then analyzed the spatial variation of different levels of vulnerability. Besides, we analyzed the relationship between environmental factors and ecosystem vulnerability, including precipitation, temperature, altitude, slope and vegetation type. The results showed that ecosystem vulnerability in the southwestern China gradually increased from southeast to northwest, with most area within the region being slight and mild vulnerable area (together occupied 69% of the total). The vulnerability level decreased with the increasing of mean annual precipitation and temperature but increased with increasing elevation and slope. Karst area in southwest and borders between farming and ranging regions in northwest Mountain ecotone of the study area had higher vulnerability, being more easily affected by climate change or other disturbances. The vulnerabilities of needle-leaved forest, grassland, and shrubland were relatively higher than other vegetation types, with the potential to be more easily affected by climate change.
    Evaluation of ecosystem cultural services of urban protected areas based on public participation GIS (PPGIS): A case study of Gongqing Forest Park in Shanghai, China.
    PENG Wan-ting, LIU Wen-qian, CAI Wen-bo, WANG Xin, HUANG Zhi, WU Cheng-zhao
    2019, 30(2):  439-448.  doi:10.13287/j.1001-9332.201902.011
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    Quantitative evaluation of ecosystem service value and its spatial mapping is an effective way to determine priority conservation areas of cultural ecosystem services (CES). We used a combination of questionnaires and structured interviews with public participatory GIS (PPGIS) in Gongqing Forest Park in Shanghai to connect non-monetary CES values with spatially explicit information. This method applied spatial indicators of abundance, diversity and rarity to quantitatively assess the value of CES and their spatial distribution, and identified priority CES areas. The results showed the value of CES varied among landscape types. Relatively open grassland, riverside, and shrub areas were associated with high aesthetic value. Riverside areas were associated with the CES category concerned with inspiration and supporting social relationships. High diversity values mainly distributed in riverside areas, while forest and grassland areas were associated with high rarity values. The areas with the highest values for the abundance, diversity, and rarity indices were overlaid with eight gradient thresholds, which indicated that defining the 25% of ecological areas with the highest overall rating as CES priority areas was an effective threshold for CES identification and management. The methodology in this study leveraged PPGIS to spatially refe-rence, quantify, and user perception to establish relationships between landscape attributes, space, and experience. These results could provide an important basis for identifying, planning for, and managing priority conservation areas in urban protected areas.
    Coordinated distributed experiments 2.0 (CDE 2.0): A novelty methodology of ecological field investigation.
    LI Ji
    2019, 30(2):  449-455.  doi:10.13287/j.1001-9332.201902.033
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    The global field experiment network is rapidly growing in ecological research in recent years. Some specific methods have emerged, such as the Coordinated Distributed Experiments (CDE), Distributed Collaborative Experiments (DCE), and field observational network of British Biological Records Centre (BRC). However, problems including too small scale, short duration and biased data are criticized in these methods. Construction of the protocol of field experiment network should follow several principles: controlled experiment prior to observation, quantity prior to quality of data, and scale prior to operation. Here, I advocated the application of citizen science to the obtaining of the data in large field, at multi-scale, and with a long duration. Environmental factors could be considered as covariant to test the dataset provided by citizen participants. Furthermore, the same dataset, as posterior probability, could be compared with the priori data set provided by ecologists to test the validity of data. This methodology, with the corresponding statistical model, would overcome the shortcoming of qualitative bias of data in citizen science. The application of priori probability, logistical relation between priori and posteriori probability, and possibility of discovering new causality of evolutionary process in ecological experimental data were discussed. Compared with CDE, CED, and BRC, this method improved the match between statistical norm and sampling quantity in large spatial and temporal scales. This new method would help discover the general theory of ecology researches and it could be termed “Coordinated Distributed Experiments 2.0” (CDE 2.0).
    Effects of different paddy-upland multiple cropping rotation systems on soil organic carbon and its fractions in paddy field.
    YANG Bin-juan, SUN Dan-ping, ZHANG Ying-rui, ZHONG Chuan, HUANG Guo-qin
    2019, 30(2):  456-462.  doi:10.13287/j.1001-9332.201902.021
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    The variations of soil organic carbon and its fractions in different paddy-upland multiple cropping rotation systems were evaluated in field trials in two consecutive years. During paddy-upland multiple cropping rotations conducted over 2 years, the content of soil total organic carbon (TOC) first increased and then decreased. The content of readily oxidized organic carbon (ROC) was highest at the rice tillering stage and lowest at the mature stage. The soil microbial biomass carbon (SMBC) was highest at the tillering stage. The dissolved organic carbon (DOC) content was highest at the mature stage. The maximum and minimum differences were at the booting stage and mature stage for TOC content, at the greening stage and booting stage for ROC content, at the mature stage and the greening stage for DOC content, at the tillering stage and the greening stage for SMBC, respectively. The soil TOC and DOC contents showed the largest variations in the ‘winter fallow-early rice-late rice → winter fallow-early rice-late rice’ rotation. The soil ROC content showed the largest variation in the ‘milk vetch-early rice-late rice → rape-peanut-late rice’ rotation. The maximum variation of SMBC was in the ‘vegetables-peanut/corn-late rice → milk vetch-early rice-late rice’ rotation. The ‘potato-maize/soybean-late rice → vegetables-peanut/corn-late rice’ rotation resulted in higher soil TOC content at the booting stage. The pattern of ‘milk vetch-early rice-late rice → oil rape-peanut-late rice’ led to higher soil ROC contents in the early and middle growth stages of late rice. In the ‘rape-peanut-late rice → potato-maize/soybean-late rice’ rotation, the highest DOC contents were at the greening stage and the mature stage, and the highest SMBC were at the booting stage and the heading stage, respectively. All these diffe-rences were significant. The rank the contents of soil organic carbon fractions from highest to lowest followed the order: TOC>ROC>SMBC>DOC. The results suggested that paddy-upland multiple cropping rotation systems could increase the contents of soil organic carbon and its fractions and improve soil quality and fertility.
    Location design of ecological barriers for river-type reservoir based on flux analysis method
    SHAN Nan, ZHANG Wen, TANG Fu-kai, PAN Yang
    2019, 30(2):  463-471.  doi:10.13287/j.1001-9332.201902.007
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    Location selection is an important scientific issue in the research and construction of water ecological barrier. Considering the characteristics of river-type reservoir with various inflow modes and large topographic fluctuation, we presented a location selection method for ecological barrier of river type reservoir based on flux analysis with the removal function of non-point source pollution of water ecological barrier. Using this method, we examined the ecological barrier location in the Three Gorges Reservoir area of China. The results showed that the role of ecological barrier for water in the study area could not be brought into full play according to the design plan of 100 m width along the coast of the Three Gorges Reservoir area. The zone of optimal function accounted for 11% of the design area, and ineffective zone accounted for 10% of the design area. 79% of the total nitrogen and 93% of the total phosphorus were concentrated in the area accounting for 21% of the total ecological barrier area and entered the reservoir. According to the flux of pollutants and their process of flow and flux, we extracted the confluence area of pollutants with high flux and area with high pollutant concentration. Based on the protection target, the ecological engineering measures to reduce the total pollutants and ensure the standard reaching of pollutant concentration were carried out respectively. This method, with full consideration of the influence of terrain on pollutant flux and classification of the key protected areas in water ecological barrier, could effectively solve the problem of location design of water ecological barrier in river-type water.
    Vertical gradients of water supply and demand in Taihang Mountains, China.
    ZHU Jian-jia, LIU Jin-tong, LIANG Hong-zhu, GAO Hui, LIU Peng
    2019, 30(2):  472-480.  doi:10.13287/j.1001-9332.201902.008
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    Taihang Mountains plays a key role in water supply for the North China Plain, even though it has the ecological disadvantages of less water and soil. Research on the vertical characteri-stics of water supply and demand in Taihang Mountains is beneficial for the sustainable management of the mountain ecosystem. Here, we quantitatively evaluated water provision in the Taihang Mountains using remote sensing data and InVEST model. Water consumption was calculated according to the index of per capita comprehensive water use in different areas. The supply and benefit areas were scientifically demarcated based on water supply to demand ratios at different altitudes. The results showed that, from 2005 to 2014, the average volume of water yield and water consumption were 65.94×108 and 45.32×108 m3, respectively, with a surplus water volume of 20.62×108 m3. On the county and catchment scales, there were water shortages in the low-altitude peripheral areas of the Taihang Mountains. However, the water shortage problem was inconspicuous for the overall mountain area, with a water supply to demand ratio of 1.53. Based on the variations in the water supply to demand ratio with respect to altitude, Taihang Mountains could be divided into three vertical bands. Areas with the altitude range of 0-300 m were water recharge areas, which were recommended for development as a complex agroforestry transition zone. Areas with the 300-950 m altitude range were water transfer balance areas, which were suggested as a maintenance zone retaining current levels of water production and consumption. Areas with altitudes greater than 950 m were water spillover areas, which should be designated for water conservation reserves with strict prohibitions regarding destruction.
    Original Articles
    Effects of Chinese fir litter cover on its seedling emergence and early growth.
    ZHAO Chong, CAI Yi-bing, HUANG Xiao, LIU Qing-qing, ZHU Chen-xi, YU Jiao-da, WANG Zheng-ning, LIU Bo
    2019, 30(2):  481-488.  doi:10.13287/j.1001-9332.201902.023
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    Litter accumulation can strongly affect seedling emergence and early growth through both physical and chemical mechanisms, and can further influence natural regeneration. Chinese fir (Cunninghamia lanceolata) is one of the most important afforestation tree species. Its natural regeneration is poor, possibly due to the thick leaf accumulation inhibiting seedling emergence and growth. We used natural and plastic litter to study the effects of Chinese fir litter on its own seedling emergence and early growth, as well as to assess whether the effect was physical or chemical. In this experiment, two litter types (natural and plastic litter) and four different litter amounts (control, 0 g·m-2; low, 200 g·m-2; medium, 400 g·m-2; high, 800 g·m-2) were used. The results showed that compared to the control (0 g·m-2), low litter amount (200 g·m-2) exerted a slight positive effect on seedling emergence, whereas high litter amount (800 g·m-2) significantly reduced the seedling emergence and survival rate in the case of both natural and plastic litter. With increasing litter amount, root length of seedlings decreased and stem length increased. The highest and lowest root mass, leaf mass, and total mass of seedlings were observed for the low and high litter amount, respectively, in the case of both natural and plastic litter. The root:shoot ratio of seedlings decreased with the increasing litter amount for both natural and plastic litter. The photosynthesis:non-photosynthesis biomass ratio of the seedlings was higher under all litter cover treatments, compared to that in the control. Because the effect of the same amounts of the natural and plastic litter on seedling emergence and early growth did not differ, the litter layer’s short-term influence was primarily physical. As the litter cover increased, the initial slight positive effects on seedling emergence and early growth could shift to inhibitory effects. Moreover, to penetrate the thick litter layer, Chinese fir seedlings allocated more resources toward stems and aboveground growth. This study provided evidence for litter amount being a key ecological factor that affects the seedling development and subsequent natural regeneration of Chinese fir.
    Responses of non-structural carbohydrates content in leaves of different plant species in Pinus tabuliformis plantation to nitrogen addition.
    ZHANG Dou, JING Hang, WANG Guo-liang
    2019, 30(2):  489-495.  doi:10.13287/j.1001-9332.201902.022
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    Through its impact on plant physiological processes, global nitrogen deposition could alter the structure and composition of forest ecosystems. However, we are not clear about the effects of N deposition on leaves’ non-structural carbohydrate (NSC) content of different plants. In this study, we compared the responses of NSC contents in seven different plant species to four nitrogen addition levels (0, 3, 6, and 9 g N·m-2·a-1, referred to as N0, N3, N6, N9, respectively), including Pinus tabuliformis, Quercus liaotungensis, Lonicera japonica, Spiraea salicifolia, Rosa xanthina, Rubia cordifolia, and Carex lanceolata in an artificial Pinus tabuliformis forest located in the hilly area of the Loess Plateau. The contents of soluble sugar and starch varied greatly in plant species, with the highest variability in R. xanthina and the lowest in S. salicifolia and C. lanceolata. There were significant differences in the responses of soluble sugar and starch contents to nitrogen addition among different species. Under N6 treatment, the variability of soluble sugar and starch in R. cordifolia came the first while S. salicifolia exceeded all other species under N3 and N9 treatments on that rating. The specific species with the lowest variability of soluble sugar and starch contents differed with nitrogen addition levels. With the increases of nitrogen addition rate, the soluble sugar content of P. tabuliformis and C. lanceolata exhibited a continuous rising trend, an opposite trend of S. salicifolia, while that of Q. liaotungensis, L. japonica, and R. xanthina decreased first and then increased, reaching its minimum at N6 treatment. The response of R. cordifolia to nitrogen addition was complex. With respect to starch content, P. tabuliformis, L. japonica and C. lanceolata showed a continuous increase trend with nitrogen addition whereas S. salicifolia decreased first and then increased, troughing at N3 treatment. R. xanthina and R. cordifolia responded complicatedly yet Q. liaotungensis appeared less responsive. Under N addition treatments, there was no explicit correlation between NSC content and soil physical and chemical properties including pH, organic carbon, total nitrogen and phosphorus. There was a significant influence of those soil properties on the soluble sugar/starch ratio under N0 or N3 treatment. Our results indicate that different species have obviously different responses of NSC to nitrogen addition. Future research concerning the impacts of global nitrogen deposition on forest ecosystems should take into account the target species, especially to pay attention to the responses of vegetation with different life forms.
    Prediction on spatial migration of suitable distribution of Elaeagnus mollis under climate change conditions in Shanxi Province, China.
    ZHANG Yin-bo, LIU Yan-lan, QIN Hao, MENG Qing-xin
    2019, 30(2):  496-502.  doi:10.13287/j.1001-9332.201902.040
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    The impacts of climate change on biodiversity and its adaptation will directly affect the efficiency of biodiversity conservation. Predicting spatial variation of suitable habitats of threatened species under future climate change has important theoretical and practical significance for biodiversity conservation. In this study, we predicted the suitable distribution of Elaeagnus mollis, an endemic endangered plant in China, under climate change at regional scales. Then, we simulated the spatial variation and migration tend of suitable distribution under different climate change scenarios by spatial analysis. The results from Maxent model showed that the two suitable distribution areas of E. mollis presented different migration trends under the future climate change scenarios: the suitable areas of Lyuliang Mountain would fluctuate slightly in latitudinal direction, while that in Zhongtiao Mountain would migrate to high elevation. Analysis of the spatial pattern change of the suitable areas indicated that the areas with obvious change occurred at the boundary of the suitable areas of E. mollis, including new suitable area and lost suitable area. The new suitable areas were scattered in the marginal of the original, with the increase rate of 9.1% to 20.9%, and the lost suitable areas were concentrated in the northern Lyuliang Mountain suitable areas and the southeast Zhongtiao Mountain suitable areas, with the loss rate of 16.4% to 31.1%. These regions were more sensitive to climate change. Using the classification statistical tool of Zonal, we found that the central points of the Lyuliang Mountain suitable areas showed southward migration trend under the future climate change, with the maximum migration distance of 7.451 km, while the center point of the Zhongtiao Mountain suitable areas showed migration trend to the northwest, with the maximum migration distance of 8.284 km. Our results indicated that the response of E. mollis distribution in Shanxi to climate change was intense.
    PM2.5 adsorption capacity of Osmanthus fragrans and Cinnamomum camphora leaf surface and influencing factors under different pollution levels in Changsha, China.
    LUO Jia, ZHOU Xiao-ling, TIAN Yu-xin, CHEN Jian-hua
    2019, 30(2):  503-510.  doi:10.13287/j.1001-9332.201902.003
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    To understand the PM2.5 adsorption mechanisms of plants under different pollution levels and analyze pollutant sources, the PM2.5 adsorption amount of the leaves of two garden plant species (Cinnamomum camphora and Osmanthus fragrans) in different polluted level area (traffic area, culture and education area, cleaning area) of Changsha was measured using an aerosol generator. AFM scanning was used to obtain leaf surface micromorphological characteristics. Ion chromatography was used to measure the water-soluble ion content. Results showed that amount of PM2.5 adsorbed by leaves was positively correlated with pollution levels. The annual mean value of PM2.5adsorbed per leaf area of different plants was traffic area (0.56±0.04 μg·cm-2) > culture and education are (0.48±0.06 μg·cm-2) > clearing area (0.33±0.02 μg·cm-2). The season with amount of PM2.5adsorbed in leaves from the highest to lowest was winter (0.70±0.10 μg·cm-2) > spring (0.43±0.14 μg·cm-2) > autumn (0.39±0.12 μg·cm-2) > summer (0.31±0.09 μg·cm-2). Osmanthus fragrans had higher capacity to absorb PM2.5 than Cinnamomum camphora. Leaves of plants grown in low pollution areas were relatively smooth, whereas those in high pollution areas were rough. The order of leaf roughness in both species from high to low was traffic area (195.45±16.09 nm) > culture and education area (176.99±8.45 nm) > cleaning area (131.88±12.98 nm). The PM2.5 ionic content was the highest in winter, intermediated in spring and autumn, and the lowest in summer. The PM2.5 ions mainly included Na+, NH4+, Cl- and Br- in three pollution areas. PM2.5 pollution was due to removable source pollution at different pollution levels.
    Distribution characteristics of surface soil organic carbon and total nitrogen in forest plantation of hilly area of Taihang Mountains, China
    FENG Xue-jin, ZHANG Zhi-hua, YANG Xi-tian, BI Hui-tao, SANG Yu-qiang, WU Ying-xia, SHI Yue-feng
    2019, 30(2):  511-517.  doi:10.13287/j.1001-9332.201902.027
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    To explore the effects of forest types and slope positions on the content of soil organic carbon (SOC) and total nitrogen (TN) in the lower hilly area of Taihang Mountains, we examined the distribution pattern of SOC and TN contents in Quercus variabilis plantation (Qo), and Platycladus orientalis plantation (Po), and abandoned land (Al). The results showed that in the same forest type or slope position, the contents of SOC and TN gradually decreased with increasing soil depth. Under different slope conditions, the contents of SOC and TN showed the tendency of upper-slope (U) > middle-slope (M) > lower-slope (L) in the planted forests (Qo and Po), but showed the tendency of L>U>M in Al. Under different forest types, the contents of SOC and TN in the U and M showed the trend of Qo>Po>Al. At the LS, the contents of SOC and TN of Al were the highest. The C/N ratio followed an order of Qo>Po> Al at U and M, while Qo>Al> Po at L. Within the same forest type, C/N of different slopes was different, but not significant. Our results suggested that the adaptability of the Qo plantation is the best in the lower hilly area of Taihang Mountains.
    Effect of planting white clover on nutrients and biological properties of soils in persimmon orchard of Weibei, Shaanxi Province, China.
    ZUO Yu-huan, LIU Gao-yuan, YANG Li-li, LIANG Lian-you, TONG Yan-an
    2019, 30(2):  518-524.  doi:10.13287/j.1001-9332.201902.020
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    Leguminous crop planting is one of the most important managements in sustainable agriculture, which has the potential to improve soil quality and environmental health by increasing N input and facilitating soil and water conservation. In this study, effects of white clover planting on soil nutrients and biological properties in persimmon orchard was investigated to understand its potential effects on improvement of soil fertility and economic performance. Soil samples were collected on September 14th, 2017 at 0-10 cm, 10-20 cm, 20-30 cm and 30-40 cm soil depth in two treatments (i.e. ploughing with no grass and planting white clover) in persimmon orchard, and were analyzed for soil available nitrogen, organic matter, microbial biomass carbon and nitrogen, and enzyme activity. Compared to the control, soil available nitrogen, organic matter, microbial biomass carbon and nitrogen, and the activities of urease, sucrase, catalase and alkaline phosphatase all increased in grass treatment. Specifically, in grass planting treatment, soil organic matter and microbial biomass carbon were significantly increased at 0-10 cm soil, and increased soil avai-lable nitrogen was found at 10-20 cm soil. For enzyme activity, significantly elevated urease activity exhibited at surface depth (0-20 cm), while catalase, sucrase activity and geometric mean (GME) of enzyme activity were higher within entire tested soil profile (0-40 cm). Overall, our results indicated white clover planting in orchard could not only facilitate soil fertility, but also reduce chemical fertilizer input and improve economic benefit, which could be considered as a good orchard cultivation mode.
    Soil particle composition, fractal dimension and their effects on soil properties following sand-binding revegetation within straw checkerboard in Tengger Desert, China.
    LUO Ya-xi, LIU Ren-tao, ZHANG Jing, CHANG Hai-tao
    2019, 30(2):  525-535.  doi:10.13287/j.1001-9332.201902.025
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    This study aims to elucidate the effects of soil particle composition and fractal dimension on soil physical and chemical properties following sand-binding revegetation within straw checkerboard in south-eastern Tengger Desert. Three afforested plantations in the year of 2016 (i.e., 1 year), 2013 (i.e., 4 years) and 1987 (i.e., 30 years) were selected as study sites, with the adjacent mobile sand land as control (CK). We measured soil particle composition, soil fractal dimension, and the changes of soil physical and chemical properties. The relationship between soil particle composition, soil fractal dimension, and soil properties was analyzed. The results showed that contents of soil particle with the size of both 100-250 μm and 250-500 μm were greater than that of 50-100 μm, ranging from 42.5% to 80.1% and from 12.5% to 42.2% relative to that ranging from 0.2% to 20.8%. Contents of soil particle with the size of <2 μm and 2-50 μm were remarka-bly lower than that of 100-250 μm, 250-500 μm and 50-100 μm, ranging from 0 to 1.3% and from 0 to 22.7%, respectively. However, contents of soil particle at the size of 500-1000 μm was the lowest occupying <0.3% of soil particle composition. Soil particle with the size of <2 μm and 2-50 μm were found in the 30-year sites only. Soil particle distribution at the size of 50-100 μm, 100-250 μm, and 250-500 μm followed the order of 30 a>1 a>4 a＞CK, 4 a>1 a>CK>30 a, and CK>1 a>4 a> 30a, respectively. Soil particle with the size of 500-1000 μm occupied little of soil particle composition, with no significant difference between each site. The fractal dimension of soil particles ranged from 0.54 to 2.59. There was significantly greater soil fractal dimension in 30 a in comparison to 4 a, 1 a and CK, with the intermediate values in 4 a and 1 a, and the lowest values in CK. There was a significantly positive correlation of fractal dimension of soil particles with soil particle content of clay, silt, very fine sand, and a significantly negative correlation of fractal dimension of soil particles with soil particle content of medium sand. Fractal dimension of soil particles was positively correlated with soil electrical conductivity, organic carbon, total nitrogen, and carbon-nitrogen ratio, but with no correlation with soil pH and soil water content. Soil particle content at the size of <2 μm, 2-50 μm, and 50-100 μm had a significant positive correlation with soil electrical conductivity, organic carbon, total nitrogen, and carbon-nitrogen ratio, whereas soil particle content at the size of 250-500 μm had a negative correlation with the former four soil indices and soil water content. In addition, there was a significant negative correlation of soil particle content at the size of 500-1000 μm with soil water content. It was concluded that the sand-binding reve-getation within straw checkerboard in Tengger Desert could facilitate the fine soil particles by ameli-orating stressful soil conditions. Long-term succession of revegetation on mobile sand land could enhance soil clay and silt content as well as soil fractal dimension, thus be beneficial for the improvement of soil physical and chemical properties and desertification control.
    Performance evaluation of GIMMS NDVI based on MODIS NDVI and SPOT NDVI data.
    ZHU Yi-xuan, ZHANG Yang-jian, ZU Jia-xing, CHE Bin, TANG Ze, CONG Nan, LI Jun-xiang, CHEN Ning
    2019, 30(2):  536-544.  doi:10.13287/j.1001-9332.201902.016
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    The study evaluated GIMMS NDVI based on MODIS NDVI and SPOT NDVI over the same period from 2000 to 2015. We assessed their absolute values, dynamics, trends and cross-relationships between any two of the NDVIs for the national scale, as well as four separate land use types, i.e., paddy field, dry land, forest, and grassland. GIMMS NDVI was numerically greater than MODIS NDVI and SPOT NDVI. The three NDVIs exhibited equal capability of capturing monthly phenological variations. During the study period, the three NDVIs showed increasing trends in most regions, with GIMMS NDVI showing the smallest increment. Pronounced differences were identified in trends between GIMMS NDVI and MODIS NDVI or SPOT NDVI in the northwest, northeast, south-central China, Tibetan Plateau and Yunnan-Guizhou Plateau, implying that GIMMS NDVI trends in these regions should be interpreted with caution. High correlations existed between the three datasets. MODIS NDVI and SPOT NDVI showed stronger correlations at national scale. The GIMMS NDVI and MODIS NDVI were in highest accordance for dry land, while MODIS NDVI and SPOT NDVI were in higher accordance for the paddy field, forest, and grassland than dry lands.
    Response of mechanical composition of fractured soil to rainfall in shallow Karst slopes in central Guizhou, China.
    YANG Yu-qiong, DAI Quan-hou, YAN You-jin, PENG Xu-dong
    2019, 30(2):  545-552.  doi:10.13287/j.1001-9332.201902.005
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    Field sampling and indoor pipette method was used to analyze the variation of soil mechanical composition of shallow Karst fissures in response to rainfall under different land uses in Karst rocky desertification region in central Guizhou. Results would supply important scientific basis and direction for further research of soil leakage in the Karst areas. The results showed that silt was the dominant component in soil mechanical composition of shallow Karst fissures, with a content of 57%. In response to rainfall, the contents of silt and clay were increased and that of fine sand was reduced in slope cropland, while the content of fine sand was reduced and that of silt was increased in grassland. The changes of mechanical composition of shallow Karst fissures in forest and shrub land were irregular. Moreover, there was a positive correlation between rainfall and the sand content of shallow Karst fissures. The fissures of land use types had effects on the changes of silt and extremely coarse sand contents with the increase of soil depth, with a decreasing trend of silt.
    Effects of long-term grazing on carbon isotope composition in plants and soils of different grasslands
    YAO Hong-yun, LI Xiao-yan, GUO Na, WANG Ying, ZHU Guo-dong, WANG Xiao-nan, WEI Jun-qi, WANG Cheng-jie
    2019, 30(2):  553-562.  doi:10.13287/j.1001-9332.201902.031
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    Grazing is a common human activity on grassland region. Long-term grazing exerts great effects on ecosystem carbon cycling. In this study, we collected leaf and soil samples from different grassland types across the growing season, separately from un-grazed (UG) and overgrazed (OG) plots. By analyzing the carbon isotope values of samples in laboratory, this study revealed the divergent Δ13C value (carbon isotope discriminative value) among different grassland ecosystems, as well as its influencing factors. The results showed that Δ13C value of soil at 0-5 cm significantly differed between UG and OG, but no difference at deeper layers (>5 cm). The grazing intensity had significant influence on the Δ13C value of vegetation leaves. After long-term grazing, most vegetation showed a significant increase in Δ13C value, especially in high altitude areas. In conclusion, grazing have significantly divergent impacts on the carbon processes under different grassland ecosystems, soil depths and altitudes. Therefore, a variety of grazing management strategies should be adopted for various grassland ecosystems.
    Effects of litter decomposition on contents and three-dimensional fluorescence spectroscopy characteristics of soil labile organic carbon in coastal wetlands of Jiaozhou Bay, China.
    SUN Xiao-lin, KONG Fan-long, LI Yue, DI Li-yan, XI Min
    2019, 30(2):  563-572.  doi:10.13287/j.1001-9332.201902.036
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    Litter of Suaeda glauca, Phragmites australis, and Spartina alterniflora from coastal wetland of Jiaozhou Bay was decomposed in a laboratory experiment. The contents of soil labile organic carbon including dissolved organic carbon (DOC) and microbial biomass carbon (MBC) were determined, with the spectra characteristics of which being investigated by three-dimensional fluorescence spectroscopy. The results showed that the contents of soil labile organic carbon during litter decomposition increased first, then decreased, and finally tended to be stable. Different litter types and adding ways had different effects on soil labile organic carbon. The contents of soil DOC and MBC decreased in the order of Suaeda glauca, Spartina alterniflora and Phragmites australis. Soil mixed with bulk leaf litter had more soil labile organic carbon than surface mulch. The number and position of fluorescence peak, and fluorescence intensity changed during litter decomposition. No tyrosine-like peaks appeared in the soil with litter addition. Many factors drove litter decomposition, with microbial decomposition being the dominant factor and litter nature as the essential factor. Litter decomposition could improve the content of soil active organic carbon and enhance the stability of soil carbon pool. Litter decomposition changed the structure and chemical composition of soil DOC, which improved its ability of migration and transformation in soil. Moreover, this process enhanced its biodegradability and microbial bioavailability, promoted the production of endogenous DOC by microorganisms, and consequently stimulated carbon cycling of wetland soil.
    Effects of cultivation patterns on wheat yield and soil fertility in dryland.
    HE Hong-xia, LI Xiao-han, BAO Ming, LI Chao, MA Xiao-long, HE Gang, QIU Wei-hong, WANG Zhao-hui
    2019, 30(2):  573-582.  doi:10.13287/j.1001-9332.201902.019
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    A field experiment was conducted to examine the effects of plastic film mulching (PM), straw retention (SR), and planting green manure (GM) on winter wheat grain yield and soil fertility. The results showed that PM did not have consistently positive effect on the grain yield, when compared to the traditional patterns (TP). No difference of average grain yield was observed between them over three years. Soil total nitrogen (N), available phosphorus (P), potassium (K), sulfur (S), zinc (Zn) and manganese (Mn) were decreased in 20-40 cm layer in PM than those in TP, while no difference was observed for soil organic matter, nitrate (NO3--N), available iron (Fe) and copper (Cu). The mean grain yield of three years decreased by 12.1% in SR than that in TP treatment. At maturity stage of winter wheat, soil total N and available Cu was increased by 5.8% in 0-20 cm and 6.2% in 20-40 cm layer, respectively, while soil available P and Mn were decreased by 36.1% and 10.2%, respectively. No difference was observed between SR and TP treatments for soil organic matter, NO3--N, available K, S, Zn and Fe at anthesis and maturity stages. Compared to the TP treatment, the mean grain yield was decreased by 12.1% in GM treatment. Soil pH, available P and S were decreased, while the soil organic matter, total N, NO3--N, and available Zn and Mn were increased. No difference was observed for soil available K, Fe and Cu. In conclusion, the PM and SR were not beneficial for the improvement of soil fertility, and thus inhibited the grain yield increase in dryland with low soil fertility level. The GM has greater potential to increase soil nutrients, but it should be paid more attention to the risk of grain yield reduction due to insufficient annual precipitation.
    Effects of fertilizer of calcium silicon magnesium potassium on the dynamics of soil acidity and exchangeable base cation in paddy field of southern China.
    JI Jian-hua, LI Xu-hua, LIU Xiu-mei, HOU Hong-qian, LIU Yi-ren, LYU Zhen-zhen, LAN Xian-jin, CHEN Jian-qiu
    2019, 30(2):  583-592.  doi:10.13287/j.1001-9332.201902.024
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    Soil acidification of large areas of paddy fields in southern China has become an important problem in rice production. Therefore, how to ameliorate or remedy the acidifying paddy soil and to exposit its mechanism has important theoretical and practical significance for rebuilding healthy soils and guaranteeing national food security. Although lime has already been extensively used to remedy acidified soils, long-term application of a large amount of lime would not only cause the soil to harden, but also disturb the balance between calcium, potassium and magnesium in the soil. Given the advantages of lower solubility and comprehensive nutrient supply, fertilizer of calcium silicon magnesium potassium (CSMP) may be used as an alternative. The aim of this study was to clarify the functions of CSMP and its effects on soil acidification in paddy fields. A four-year field experiment was conducted to investigate the dynamics of soil pH, exchangeable acidi-ty, exchangeable base cation and available silicon, as well as 0~30 cm pH buffer capacity (pHBC), net base production under CSMP fertilization in the paddy soil. There were five treatments, i.e. CK (traditional fertilization practice of the local farmers), treatment I (CK plus 750 kg·hm-2 CSMP); treatment II (CK plus 1125 kg·hm-2 CSMP), treatment III (CK plus 1500 kg·hm-2 CSMP), and treatment IV (CK plus 1875 kg·hm-2 CSMP). The results showed that the traditional fertilization practice of the local farmers resulted in a decline of soil pH, soil exchangeable base cation and base saturation year by year, but soil exchangeable acid was increased with year. Conversely, CSPM fertlization significantly raised soil pH, with the magnitude of increases positively depending on the number of application times or application rate. Continuous and repeated application of CSMP effectively promoted the accumulation of exchangeable base cation and the consumption of soil exchangeable acid in paddy soil, especially for the accumulation of soil exchangeable Ca2+, Mg2+ and the consumption of soil exchangeable Al3+. Furthermore, the more amount of CSPM application resulted in the more accumulation or consumption, but with relatively slower rate. The exchangeable base cation and alkali released by CSMP contributed 108.8% to the total reduction of soil exchangeable acid, suggesting that it was the main path to reduce soil exchangeable acid. Meanwhile, CSMP application improved soil acidity in paddy field, with the content of available silicon increased year by year and the increase amplitude became larger with the more amount of CSMP application. The traditional fertilization of local farmers resulted in soil acidification, with a acidification rate was 2.86 kmol H+·hm-2·a-1. CSMP application could effectively control soil acidification, producing a lot of alkalinity with net alkalinity production of 9.93-13.82 kmol OH-·hm-2·a-1. CSPM could release Ca2+, Mg2+ and alkali, which would mitigate soil acidification in paddy fields.
    Spatial and temporal changes of farmland soil acidification and their influencing factors in different regions of Guangdong Province, China
    ZHENG Chao, GUO Zhi-xing, YUAN Yu-zhi, GUO Ying, CHAI Min, LIANG Xue-ying, BI Ru-tian
    2019, 30(2):  593-601.  doi:10.13287/j.1001-9332.201902.030
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    Based on the three datasets from 1980s, 2010 and 2015 in Guangdong Province, we analyzed the spatial and temporal variations of soil pH in farmlands in different regions of Guangdong Province and analyzed the driving factors for such variations. The results showed that the spatial distribution of soil pH in Guangdong Province changed significantly in different periods. During 1980s to 2010, soil pH showed an acidification trend with a decline of 0.3, and increased by 0.09 from 2010 to 2015, with more uneven trend and more obvious acid base differentiation. From the perspective of each region, there was generally a trend of acidification from the 1980s to 2010. From 2010 to 2015, the average pH value of farmland soil in the Pearl River Delta increased by 0.27, while that on the east wing and west wing decreased by 0.05 and 0.15 respectively, showing a unapparent change of soil pH in the mountainous area. Our results showed that soil acidification in diffe-rent areas of Guangdong Province was affected by natural factors such as soil itself and precipitation. In addition, anthropogenic factors such as acid rain, unreasonable fertilization and the planting structure of high-yielding crops were also the main causes of soil acidification. Industrialization, urbanization, mining development, and the spread of soil testing formula fertilization increased soil pH in local areas. Our results could provide theoretical guidance for controlling and alleviating soil acidification and improving the quality of cultivated land in different areas.
    Effects of biological agent dripping on cotton Verticillium wilt and rhizosphere soil microorganism.
    LYU Ning, SHI Lei, LIU Hai-yan, SI Ai-jun, LI Quan-sheng, ZHANG Guo-li, CHEN Yun
    2019, 30(2):  602-614.  doi:10.13287/j.1001-9332.201902.032
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    Biological agent is an important green pathway to control Verticillium wilt. A field experiment was performed to examine the effects of Bacillus subtilis agent (15, 30 and 45 kg·hm-2), Trichoderma humatum agent (15, 18 and 24 kg·hm-2), ‘Yufeng 99’ agent (15, 22.5 and 30 kg·hm-2) and Zhongnonglyukang agent (30, 45 and 60 kg·hm-2) on cotton Verticillium wilt and soil microbial community. The results showed that all of the four biological agents could reduce the incidence and index of cotton Verticillium wilt, with control effects of 50.0%-77.4% in the whole growth period of cotton. The control effects of B. subtilis, ‘Yufeng 99’ and Zhongnonglyukang agent were positively correlated with the application doses, while that of T. humatum agent of 18 kg·hm-2 was significantly higher than 15 and 24 kg·hm-2. The relative abundance of V. dahliae was significantly reduced, which was negatively correlated with the control effect. The quantity and species richness of soil bacteria were significantly increased with the increases of application doses. The quantity and species abundance of actinomycete were significantly increased, while the quantity of actinomycete varied greatly among different application doses. The quantity and species richness of fungi increased with the increased application doses of T. humatum agent, but was decreased with the increased application doses of other three biological agents, respectively. The control effect was positively correlated with the quantity of bacteria and actinomycetes, but was negatively correlated with that of fungi. Meanwhile, the control effect was significantly and positively correlated with the abundance of Actinomycetes, Nitrospirae, Ascomycota, Chytridiomycota, but was significantly and negatively correlated with that of Deuteromycota. The application doses of ‘Yufeng 99’, zhongnonglyukang, B. subtilis and T. humatum agents were suggested to be 30, 60, 45 and 18 kg·hm-2, respectively.
    Construction of Wuhan’s ecological security pattern under the “quality-risk-requirement” framework.
    HUANG Long-yang, LIU Sheng-hua, FANG Ying, ZOU Lei
    2019, 30(2):  615-626.  doi:10.13287/j.1001-9332.201902.014
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    The ecological security pattern aims to maintain the integrity of landscape pattern and the continuity of ecological process to ensure urban ecological security. Current ecological source identification methods lack the consideration for ecological land degradation risks and human ecological needs. Taking Wuhan City as an example, the comprehensive value of ecological land was calcula-ted from three aspects, including ecological land quality, ecological degradation risk, and ecological demand to identify ecological source areas. Basic ecological resistance surfaces were constructed based on land use types and nighttime light data. Potential ecological corridors were identified based on the minimum cumulative resistance model. Ecological “pinch points” were recognized based on circuit theory. After that, we built a “four horizontal, three vertical and ten groups” ecological safety pattern in Wuhan. The results showed that the area of ecological land in Wuhan was 2138.2 km2, accounting for 24.9% of the total area of the city. These areas were primarily attributed to waters and foress, clustering in the north and south of the city. The total length of ecological corridors was 1222.42 km, with 566.75 km aquatic corridors and 655.67 km land corridors. The aquatic corridors traversed the city area to form a double cross-shaped pattern. The land corridors circularly distributed around the city. Comprehensively, the “four horizontal and three vertical” spatial pattern had appeared. There were a total of 44 ecological pinch points on the ecological corridor, distributed circularly with the central city as the kernel. The extant protection space had almost been included in the identified ecological source area, supporting the ecological significance of the identification framework. It would help to provide a quantitative framework for the construction of ecological secu-rity pattern in the metropolitan area and to guide the relevant urban spatial planning.
    Evaluation of carrying capacity and spatial pattern matching on urban-rural construction land in the Poyang Lake urban agglomeration, China.
    YI Dan, ZHAO Xiao-min, GUO Xi, JIANG Ye-feng, WANG Cheng-liang, LAI Xia-hua, HUANG Xin-yi, CHEN Lei
    2019, 30(2):  627-636.  doi:10.13287/j.1001-9332.201902.004
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    Land carrying capacity is one of the important research fields for land management and sustainable use. Urban-rural construction land is an essential component of land use type, the rationality of whose structure and layout is crucial to the sustainable use of land. Here, we executed the evaluation of the suitability of urban-rural construction land development, accounted the bearable critical threshold of urban-rural construction land, calculated the bearable abundance of urban-rural construction land, and compared with the current urban-rural construction land, analyzed the matching of the space layout, and then obtained the remaining development intensity of each county (city or district) of the Poyang Lake urban agglomeration. The results showed that the most suitable, more suitable, less suitable and unsuitable area about the evaluation results of urban-rural construction land development suitability were 3130.62, 2477.29, 867.03 and 29509.14 km2, respectively. The bearable critical threshold of urban-rural construction land (developable strength) was 16.6%, and the value of each county (city, district) was 7.7%-100%. The abundance of urban-rural construction land in each county (city, district) was mainly 0.15-1.30. The remaining development intensity was 12.3%, and the spatial matching degree was 0.76. The remaining develo-pment intensity of each county (city, district) was 4.9%-53.5%, and the spatial matching degree of each county (city, district) was 0.11- 1.00, with a wide range. Our results would help to clarify the relationship between the current development status and the rational development status, which could provide a basis for the refined management of urban-rural construction land and the regulatory policies’ formulation of spatial pattern optimization.
    Simulated study on the effects of smoke on Sphagnum spore germination.
    KANG Yuan, BAI Xiao-shan, BU Zhao-jun, FENG Lu, GUO Hong-mei, YANG Yun-he, LI Liang
    2019, 30(2):  637-643.  doi:10.13287/j.1001-9332.201902.035
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    Moderate smoke could facilitate seed germination, but its effects on bryophyte spore germination is still unknown. Here, we analyzed the effects of smoke, capsule size and storage time on the spore germination of Sphagnum squarrosum and S. magellanicum, with the capsules of which being collected from two peatlands of the Changbai Mountains. The smoke solution prepared by burning peatland plants was combined with the capsules with different sizes (large, 2.10-2.50 mm in diameter; small, 1.50-1.90 mm in diameter) and storage time (old, being stored for 4.3 or 6.3 a; new, being stored for 0.3 a) to conduct a factorial experiment. The spores were soaked with smoke solution for different durations and then cultured for germination. The results showed that smoke solution affected spore germination. After 10 d cultivation, germination rate of spores soaking with smoke solution for all duration was increased by more than 5-fold, with the small spores having higher germination rate. After 21 d cultivation, the facilitative effect was only observed in moderate soaking (3 d), and spore size showed no effect on germination. Smoke solution could not increase the germination of spores from the capsules with long storage time (4.3 and 6.3 a). Our results indicated that moderate smoke solution soaking might accelerate germination of Sphagnum spores including small pores. In the ecosystems with casual fire disturbance such as peatlands, similar with its effects on the seed plants, smoke might play a key role in the regeneration and persistence of bryophyte population.
    Comparison of generalized additive model and boosted regression tree in predicting fish community diversity in the Yangtze River Estuary, China.
    WU Jian-hui, DAI Li-bin, DAI Xiao-jie, TIAN Si-quan, LIU Jian, CHEN Jin-hui, WANG Xue-fang, WANG Jia-qi
    2019, 30(2):  644-652.  doi:10.13287/j.1001-9332.201902.037
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    Yangtze River Estuary is the biggest estuarine ecosystem in the western Pacific Ocean. Evaluating fish community in this ecosystem can provide scientific basis for its restoration and mana-gement. Generalized additive model (GAM) and boosted regression tree (BRT) were built to examine the relationship between fish community diversity and environmental and spatio-temporal variables based on data collected during 2012-2014. Combined with linear regression analysis, a cross validation was used to evaluate the fitness and predictive performance of both models. We plotted the spatial distribution of fish community diversity and richness in each station of the Yangtze River Estuary in 2014. The results showed that salinity, pH and chlorophyll-a had the most contribution on diversity, while pH, dissolved oxygen and chlorophyll-a were the most contributive variables on richness. BRT models showed better fitness and lower prediction error than GAM models. In contrast to GAM models, BRT models could distinguish the fish community index in each station area with respect to the spatial prediction. The diversity index in external water was obviously greater than that in internal water. Meanwhile, the station at higher latitude had a higher diversity index in both external and internal water.
    Element composition in the statoliths of Sthenoteuthis oualaniensis squid in Xisha islands waters of South China Sea.
    LU Hua-jie, CHEN Zi-yue, TONG Yu-he, ZHANG Xu, LIU Wei, CHENG Xin, CHEN Xin-jun
    2019, 30(2):  653-660.  doi:10.13287/j.1001-9332.201902.029
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    Sthenoteuthis oualaniensis is the most important cephalopods fishery resource of the South China Sea, which supported the falling-net fishery of Guangdong, Guangxi and Hainan Provinces of China. Understanding the fisheries biology is essential for sustainable exploitation and management of this squid. Statolith is one of the most important hard tissues of cephalopods which were widely used in the research of fisheries biology and ecology. Elements of 20 statoliths of S. oualaniensis collected in the Xisha islands waters of South China Sea during May to August by the falling-net fishery of 2017 were analyzed with Laser ablation inductively coupled plasma mass spectrometry (LA-ICP-MS) for different sexes, different hatching groups, and history stages. The results showed that the statolith of the S. oualaniensis contained 55 elements, with calcium (Ca), strontium (Sr), sodium (Na), phosphorus (P), silicon (Si),magnesium (Mg), potassium (K), iron (Fe), barium (Ba) and boron (B) being the top ten abundant elements. The analysis of variance (ANOVA) showed that there was no significant difference in all element distributions between sexes for the most abundant ten elements. Significant differences existed in the contents of Si, Sr, Mg, Na and K but no significant difference was found in the contents of Ca, P, B, Fe and B between different hatching groups. There were significant differences in the contents of Sr, Na, P, K, Si, Mg, B and Ba, but no significant difference in the contents of Ca and Fe in the statoliths among different growth zones. Our results suggested that Sr, Na, K and Mg were probably the best four elements for life history reconstruction and examining population structure of the S. oualaniensis.
    Boldness of the alpine musk deer in captivity during non-mating season and its relationships with the musk secretion and reproduction success
    LIU Xiao-bing, DONG Xia, LI Yong, ZHOU Mi, SHENG Yan, GUO Feng-peng, ZHOU Yan-rong, MENG Xiu-xiang
    2019, 30(2):  661-667.  doi:10.13287/j.1001-9332.201902.038
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    This study was conducted in 2017 from July 1st to August 31st at Xinglongshan musk deer farm in the Xinglongshan National Nature Reserve of Gansu Province, where we recorded behaviors and locations of 29 captive musk deer using the integrated methods of focal sampling and all occurrence recording. Based on the location selection patterns under artificial stress, we defined the animal’s stress level and quantified individuals’ boldness by combination with the occupation time ratio at each level. Then, the effects of gender, age-class, and other factors on boldness were analyzed along with musk secretion and reproduction success. The results showed that musk deer in better health (1.731±0.347) were significantly bolder than those in ill health (0.915±0.789). Female musk deer (1.901±0.391) were significantly bolder than the males (1.035±0.120). The boldness of sub-adults (1.450±0.463) was higher than those of the adults (1.093±0.321) and the old (1.430±0.189). No significant difference in boldness was observed among three age-classes under the same gender. Deer living in groups (1.397±0.179) were not significantly bolder than those living alone (0.853±0.326). More individuals in groups, less boldness. Furthermore, there was negative correlation between male’s boldness and musk secretion. The litter size had positive relationship with boldness. The non-pregnant percentage was strongly correlated to the boldness, namely the bolder females had lower non-pregnant ratio. Our results provide reference for forecasting the musk secretion and reproduction success of captive musk deer, and provide new ideas for the study of boldness in captive animals.
    Reviews
    Transformation and distribution of straw-derived carbon in soil and the effects on soil organic carbon pool: A review.
    YANG Yan-hua, SU Yao, HE Zhen-chao, YU Man, CHEN Xi-jing, SHEN A-lin
    2019, 30(2):  668-676.  doi:10.13287/j.1001-9332.201902.026
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    Farmland soil organic carbon (SOC) pool is a crucial component of global carbon cycle. Due to the widely-implemented straw returning, crop straws have become the primary exogenous carbon source for agricultural soils. The conversion and distribution of straw-derived carbon in soil directly affect the composition and contents of SOC, with further influence on soil nutrient cycling. Based on recent studies, this review investigated the factors impacting the transformation and distribution of straw-carbon; introduced the microbial composition that contributes to the assimilation of carbon from straw; and summarized the effects of straw-carbon on the composition, content, and turnover of SOC. Additionally, we proposed the future research regarding the effects of abiotic factors on the bio-transformation of straw-carbon; the interaction between biotic and abiotic factors during the straw carbon transformation processes; the coupling of carbon and nitrogen from straws into the soil carbon and nitrogen cycles; and the effective control over the transformation of straw-carbon that enters the active or stable soil organic carbon pool. The purpose was to reveal variation characteristics of SOC during straw returning, and provide theoretical basis and technical support for the efficient fertilization and carbon sequestration of straw returning.
    Effects of global change on methane uptake in forest soils and its mechanisms: A review
    HE Shan, LIU Juan, JIANG Pei-kun, ZHOU Guo-mo, LI Yong-fu
    2019, 30(2):  677-684.  doi:10.13287/j.1001-9332.201902.028
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    Elevated atmospheric CO2 concentration, altered precipitation regime, increased nitrogen deposition, and land cover change have not only changed the physical and chemical properties of forest soils, but also affected plant growth and microbial activity, with concequences on soil carbon and nitrogen cycles, including soil CH4 uptake. In this study, we summarized the important role of soil CH4 uptake in forests under global change scenarios. The differences of responses as well as the underlying mechanisms of soil CH4 uptake in forests to global change were reviewed. Elevated atmospheric CO2 concentration inhibits soil CH4 uptake. Reduced precipitation tends to promote soil CH4 uptake. Increased nitrogen input inhibits soil CH4 uptake in nitrogen-rich forests, but promotes or has no effects on soil CH4 uptake in nitrogen-poor forests. Conversion of forests to grassland, farmland, or plantations would reduce soil CH4 uptake, while afforestation increases soil CH4 uptake. The future research should explore the long-term and multiple effects of global changes on forest soil CH4 uptake. In addition, molecular biology methods should be developed to explore the microbial mechanism of soil CH4 uptake.
    Ecological environmental effects of land consolidation:Mechanism of action and application path.
    LIU Chun-fang, XUE Shu-yan, WU Ya-han
    2019, 30(2):  685-693.  doi:10.13287/j.1001-9332.201902.018
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    With the continuous implementation of ecological civilization and the transformation of multi-functional land management, the ecologicalization of land consolidation has entered a critical period of theoretic innovation and practical application. Systematically combing the development of theoretical research and practical exploration of ecological environment effect of land consolidation, and clarifying the service direction and implementation path of the land science discipline research under the “New Era” are urgent for the implementation of the “ecological” land consolidation stra-tegy. We reviewed the literatures on the ecological environment effects of land consolidation in the past 18 years. Using Citespace 1.0 software as analysis tool, we identified the research hotspots of ecological environmental effects of land consolidation, and discussed the mechanism of ecological environmental effects of land consolidation based on the analysis of relationship among ecological environment elements, ecological landscape and ecosystem services. Further, we proposed a new application path of “ecological” land consolidation from the measurement of regional ecosystem service level and the diagnosis of obstacle factors, the impact of land consolidation on regional ecosystem services and its mechanism, and the construction of ecological land consolidation model based on the promotion of ecosystem services, which aimed to provide a scientific basis for the restoration and construction of the life community of “mountains, rivers, forests, fields, lakes and grasses” in China.
    Intercellular electron transfer and its eco-physiological significance: A review.
    CHEN Wen-da, NI Wei-qi, HU Bao-lan, ZHENG Ping
    2019, 30(2):  694-702.  doi:10.13287/j.1001-9332.201902.034
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    Intercellular electron transfer (IET) refers to the process within which electrons being indirectly or directly transferred to the exterior of cells and eventually delivered to the electron acceptors around cells. IET widely exists in nature, especially when electron acceptor are deficient. IET can be divided into two categories: indirect IET and direct IET. Indirect IET (intercellular substrate transfer) always occurs with electron transfer of hydrogen, formate, and other metabolites. Direct intracellular electron transfer is achieved by the coupling of intracellular and extracellular electron transfer. IET boosts the activity of cellular substrate metabolism and expands the acting space of cells. Moreover, IET generates electric current which provides driving-power for energy sharing between bacteria and transformation of extracellular material (such as heavy metals and humus). There is no doubt that IET has physiological and ecological significance. This review summarized recent advances, making a systematic analysis of the process, characteristics, mechanism and eco-physiological significance of IET.
    Invasive population establishment of Asian honeybee Apis cerana.
    DING Gui-ling, AN Jian-dong
    2019, 30(2):  703-710.  doi:10.13287/j.1001-9332.201902.039
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    Bees, wasps, and ants are among the most highly invasive social insects. Theoretically, the single-locus complementary sex determination (sl-CSD) would hinder the establishment of invasive population with limited founders. Apis cerana has colonized many regions with anthropogenic movement, with devastating effects on the commercial A. mellifera. Here, we summarized the distribution and sex determination mechanism of A. cerana, the recent research results about the invasive A. cerana in Australia, and analyzed how they counteracted the handicap of their sex determination system by the queen’s extreme polyandry, worker’s reproduction, balancing selection and thelytoky. The knowledge reviewed here could be used as the reference to reveal the establishment mechanism of invasive populations of related social insects.