Table of Content

Volume 39 Issue 2
25 February 2023
The Policy and Technical System of Eco-environment Protection and Restoration in European Union and Its Enlightenment to China
ZHANG Qian, Lü Fei-nan, YU Zhen-rong
2023, 39(2):  137-145.  doi:10.19741/j.issn.1673-4831.2021.0589
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Eco-environmental degradation has become one of the key factors restricting the health of ecosystems and human well-being around the world. How to mitigate and solve the problem of eco-environmental degradation has become an important content for countries to explore sustainable economic and social development. The European Union (EU) re-alized the seriousness of the eco-environmental problems earlier, and has formed a relatively sound policy system of envi-ronmental integration and established an innovation-driven technology practice system through long-term exploration, which has played an important role in maintaining the sustainable development of the EU. At present, China is at an important juncture of eco-environmental protection. To fully understand the policy and technical practice system of eco-environmental protection and restoration of the EU will be helpful to promote the cause of eco-environmental protection in China. On the basis of relevant literature research and analysis, this paper summarizes the status of eco-environmental protection in the EU, and systematically sorts out the relevant policy systems and technical measures. The paper also proposes that in the fu-ture, eco-environmental protection and restoration should be incorporated into multiple departments, and environmental management mechanisms with public participation should be explored in the field of policy. In terms of innovation of tech-nical measures, it is necessary to promote the localization and mainstream development of nature-based solutions, and build a platform for innovation and exchange of technical measures based on enterprises and multi-participation.
Index System of Evaluation of Rural Environmental Quality under the Background of Rural Revitalization:A Review
LI Yan, ZHANG Guo-qing, YU Ge
2023, 39(2):  146-155.  doi:10.19741/j.issn.1673-4831.2021.0663
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Rural areas play an important role in the construction of ecological civilization under the background of rural revitalization. Evaluation of environmental quality started relatively late in China, and at the beginning it was mainly carried out in large cities, large river basins and other large-scales, with much less focus on the environmental protection and assessment of small-scale rural areas. By carrying out comprehensive evaluation of rural environmental quality, it can help to solve the problem of disharmony between the social and economic development and the environmental protection in the process of rural development. The scientific evaluation of rural environmental quality and the corresponding improvement measures are the top priorities of the whole rural revitalization blueprint planning. This study summarizes the research methods and progress of environmental monitoring and evaluation in rural areas in recent years from the aspects of index system, research methods and development proposals, and puts forward some suggestions on the construction of evaluation indexes for rural environmental quality.
Study of the Impact of Livelihood Differentiation on the Decision-making Behavior of Farmers' Adoption of Environment-friendly Technology
ZHANG Jie, CHEN Mei-qiu, YAN Yu-qi, LI Xing-yi
2023, 39(2):  156-165.  doi:10.19741/j.issn.1673-4831.2022.0044
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Based on the micro-data from the surveying on 1092 farmer households in Jiangxi Province, the Triple-Hurdle model was used for analyses on the impact of farmer households' willingness to adopt, their adoption behavior, and their decision-making behavior on environment-friendly technologies. Seven dimensions of livelihood capital, including natural, manpower, social, physical, financial, ecological, and psychological were considered for the analyses. The analyses started from the prominent phenomenon of livelihood differentiation of farmer households in the current rural society. The results show that:(1) The number of farmer households who are willing to adopt soil testing and fertilizer application technology accounts for 81.96% of the sample, of which 24.13% have finally adopted the technology, and the degree of adoption is 91.60%, which still has more room for improvement. (2) Farmer households' willingness to adopt, adoption behavior and adoption degree are influenced by a combination of the seven demensions of livelihood capitals and are somewhat heterogeneous. (3) Human capital and social capital have less influence on farmer households' adoption behavior of environment-friendly technologies, and social capital and ecological capital have less influence on farmer households' adoption degree. Based on the results of the survey, for promoting the transformation of farmer households' willingness into real actions, the following measures are proposed:to increase investment for farmland water conservancy and rural education, to improve and perfect land transfer, to increase subsidies for the purchase of large farm machinery, to promote the use of energy-saving products, to strengthen the publicity of relevant technologies, to improve the construction of demonstration, training and promotion systems, and to develop corresponding technical service measures according to various types of farmer households.
Research on the Influence of Internal Perception and External Environment on Green Fertilization Technology Adoption Behavior of Farmers
ZHANG Hua-nan, GE Yan-xiang
2023, 39(2):  166-173.  doi:10.19741/j.issn.1673-4831.2021.0767
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As the decision-making body of fertilizer application, farmers' decision-making and degree of adoption of green fertilization technology are affected by internal perception and external environment. Systematic analysis on the adoption behavior of green fertilization technology of farmers has important theoretical and practical significance to the promotion of the green and high-quality development of agriculture and the ecological environment. Based on the micro data of field survey on 680 apple growers in Shandong Province, the Heckman model was used to empirically analyze the influence and differences of internal perception and external environment on farmers' decision-making on the adoption of green fertilization technology and the adoption degree. The results show that:firstly, farmers have "high willingness but low action" on adoption of green fertilization technology, and the average adoption degree is not high. Secondly, technology perception has significant positive impact on farmers' behavior on the adoption of green fertilization technology, and the influence of economic value on farmers' behavior on the adoption of green fertilization technology is significantly greater than that of the social value and ecological value. Thirdly, the directive norms and exemplary norms representing the external environment have significant positive influence on the farmers' decision on the adoption of green fertilization technology, and the ecological compensation has a significant impact on the adoption degree. Therefore, in order to encourage the enthusiasm and initiative of farmers to adopt green fertilization technology, the publicity and education on green fertilization technology should be enhanced, new agricultural business entities should be actively promoted, and the internal motivation of farmers on the adoption of green fertilization technology should be improved.
Landscape Pattern Optimization in Baiyangdian Basin Based on Landscape Ecological Risk Assessment
GAO Xing, SONG Zhao-ying, LI Chen-xi, TANG Huai-zhi
2023, 39(2):  174-183.  doi:10.19741/j.issn.1673-4831.2021.0796
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Watershed landscape ecological risk assessment is the realistic basis of landscape pattern optimization, and landscape pattern optimization is one of the effective ways of watershed ecological environment restoration and maintenance. Taking Baiyangdian Basin as the study area, 11 indicators were selected from three aspects of nature, human activities and landscape factors. The spatial principal component analysis method was used to evaluate landscape ecological risk of the basin. The water body with an area of more than 0.001 km2 and the forest land with an area of more than 0.005 km2 were identified as the ecological sources in the basin. Based on the results of the risk assessment, MCR model and network structure evaluation method were constructed to optimize landscape pattern of the basin. The results show that, (1) Natural factors such as vegetation coverage and runoff have the most significant impact on landscape ecological risk in Baiyangdian Basin, and landscape factors have the least impact on ecological risk. (2) The landscape ecological risk of Baiyangdian Basin is relatively high. The high-risk regions are located in the southeast and northwest of the study area, and the low-risk areas are scattered in the forest land in the west. The total area of the extracted ecological source is 11 319.85 km2, accounting for 35% of the total area of the basin. (3) The ecological network pattern composed of 39 ecological corridors and 21 ecological nodes has been constructed, forming road corridors, river corridors and green belt corridors. After optimization, it is found that the network closure, node connection rate and network connection degree of the landscape pattern are high, and the connectivity of landscape pattern has been significantly improved. The research of the landscape pattern optimization based on landscape ecological risk assessment is conducive to providing a scientific basis and decision-making reference for the comprehensive promotion of ecological environment maintenance and restoration in Baiyangdian Basin.
Source Analysis of Chemical Components of Atmospheric PM2.5 in Nantong Region Based on Super Station Data
ZHANG Xiang, CAO Zhi-gang, CUI Ping
2023, 39(2):  184-189.  doi:10.19741/j.issn.1673-4831.2021.0682
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For exploring the source of PM2.5 of Nantong in 2020, the characteristics, correlation and industrial contribution of chemical components of PM2.5, and the internal and external seasonal contribution of PM2.5 were analyzed based on the high time resolution observation data of super stations. At the same time, WRF-CMAQ model was used to construct meteorological field and pollutant field for the simulation of the ambient air quality of Nantong in January, April, July and October of 2020. The results show that the secondary inorganic ion is the main component of PM2.5 in Nantong City, and their concentrations have obvious seasonal difference. The sharp increase of nitrate concentration is an important reason for the aggravation of PM2.5 pollution in Nantong city. The aggravation of PM2.5 pollution level in winter was affected mainly by vehicle exhaust emission. From the perspective of 2020 as a whole, according to different meteorological conditions and pollution types in different seasons, the proportions of the pollution sources were also different. The local emission contribution of PM2.5 in Nantong is about 61%, followed by long-distance transmission from the north (17%), and from the Yangtze River Delta and southern Jiangsu (18%). The verification on the simulation of all pollutants in the air quality model can well represent the change trend of pollutants. Although, there is a certain gap between the simulated value and the observed value, it is still within a reasonable and acceptable range. The results worked out by the model are reliable and can be used in subsequent researches.
Contamination Characteristics and Water Ecological Risk of Polycyclic Aromatic Hydrocarbons in the Soil from Riparian Area of Miyun Reservoir
LIU Yi, JIANG Xuan, WANG Xia, ZHANG Qing-zhuo, ZHAO Gao-feng, WANG Xiao-yan
2023, 39(2):  190-196.  doi:10.19741/j.issn.1673-4831.2021.0560
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Affected by the South-to-North Water Diversion Project and seasonal rainfall, the water level of Miyun Reservoir rose year by year and formed periodic water fluctuations on the riparian area, which could change the ecological environment and affect the storage and release of polycyclic aromatic hydrocarbons (PAHs) in the soil. In order to explore its potential risks to the water environment, the surface soil and sediment samples of the riparian area were collected with an elevation between 130 and 150 m. GC-MS (gas chromatography and mass spectrometry) were used for analyzing the content level and composition characteristics of 16 PAHs for priority control, and their distribution characteristics under different elevations, sources and their potential ecological risks were studied. The results show that:(1) 16 PAHs are commonly found in the surface soil and sediment of the riparian area. The contents of ∑16PAHs range from 66.74 to 481.34 ng·g-1, and the pollution level is lower than that of the sediments in the reservoir. (2) Similar to the composition of PAHs in the sediments, the PAHs in the soil and sediment on the riparian area of the reservoir are mainly low-middle-rings. Naphthalene, phenanthrene, anthracene, and pyrene are dominant compounds. Source apportionment shows that the main source of PAHs is the burning of local biomass (farmland residues or vegetation), which is closely related to human activities. The Baihe storage area shows the characteristics of a mixed source, and the source of PAHs is related to the pollution of petroleum discharge. (3) The contents of PAHs in 3 different elevation of 130-140, >140-145, >145-150 m are 177.06, 223.86 and 212.63 ng·g-1, respectively, and the low-ring PAHs are the main component. (5) The ecological risk assessment shows that most of the soil samples are less likely to produce negative ecological benefits. Only the riparian area of Baihe, the northern flooded area and the eastern area of the reservoir have potential ecological risks.
Species Diversity Characteristics of Native Seed Plants in Eastern Coastal Area of Jiangsu:A Case Study of Guanyun County
YE Peng-cheng, ZHAO Xiao, CHEN Hui, SI Qin, WU Jian-yong
2023, 39(2):  197-206.  doi:10.19741/j.issn.1673-4831.2021.0670
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Many plants are threatened to varying degrees due to frequent land development activities in the eastern coastal areas of Jiangsu. We selected the flora of Guanyun County in Lianyungang City as study object. In order to study the flora and species diversity characteristics of native seed plants in this area, a comprehensive survey method was used in combination with line survey, sampling survey and special area investigation. In addition, the floristic characteristics of this County was compared with those of four surrounding Counties in the eastern coastal area of Jiangsu. The results indicate that:(1) there were 357 species belonging to 240 genera and 72 families of native seed plants in this County. Angiosperms were dominant and gymnosperms were scarce. The diversity of native seed plants species is higher in this Conunty than that of in the adjacent Counties. (2) At the family level, there were 6 areal types of native seed plants, among which the tropical and temperate components accounted for 58.33% and 41.67%, respectively; at the genus level, there were 14 areal types of native seed plants, among which the tropical and temperate components accounted for 37.25% and 61.75%, respectively, and the ratio of tropical genera to temperate genera (R/T value) was 60.32%. (3) Guanyun county has the most abundant herbaceous plant species, and the species richness index (R), Shannon-Wiener diversity index (H) and Simpson dominance index (D) of herbaceous layer were significantly higher than those of the tree layer and shrub layer (P<0.001). (4) From coastal to inland (from east to west), with the increase of the distance from the sea, the species richness index (R) of herbaceous plants increased significantly (P<0.05), while the Pielou evenness index (J) of herbaceous plants decreased significantly (P<0.001). (5) There was high species diversity in the central and western parts of Guanyun County, especially in Yilu mountain and Dayi mountain and their surrounding areas, which were the key areas for biodiversity conservation. (6) the similarity coefficients (SC) of native seed plants genera between Guanyun County and its four surrounding areas of Northern Jiangsu Plain were all above 50%, and the similarity coefficient of native seed plants flora of Guanyun County with Guannan County was the highest (SC=61.96%). Guanyun county is an important part of the eastern coastal area of Jiangsu Province. This study provides the foundational data for effective conservation, scientific management and sustainable utilization of native plant diversity in Guanyun County.
Driving Mechanism of Spatial Evolution of Rural Settlements in the Yaoluoping National Nature Reserve, Anhui Province
QIAN Zhe-dong, CAO Xiao, CHEN Hao, Lü Ying-ying, GAO Jun, ZHANG Hao-nan
2023, 39(2):  207-213.  doi:10.19741/j.issn.1673-4831.2021.0823
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Many nature reserves in China face the dual historical tasks of ecological protection and rural revitalization. To study the driving mechanism of spatial evolution of rural settlements in nature reserves is of great significance for coordinating rural development and ecological protection in nature reserves. Using GIS technology, landscape pattern index, kernel density and multiple linear regression model, the driving mechanism of spatial evolution of rural settlements in Yaoluoping Nature Reserve from 1999 to 2019 was analyzed. The results show as follows:1) the area, the number of patches and the size of individual patches of the Yaoluoping Nature Reserve showed an increasing trend over the 20 years, and the morphology of the settlements changed to a complex and irregular state, with significantly more new settlements in the experimental area than those in the core area and the buffer area, and the irregularity of the patches in the core area was higher than that in the buffer area and the experimental area. 2) The distribution of settlements in the nature reserve is characterized by dense in the north and sparse in the south, with obvious directionality of roads, water systems and altitude. The high-density areas showed an increasing trend and gradually merged as one area. The expanded and increased high-density areas were basically all located in the experimental area, and the agglomeration degree of settlements in the buffer area decreased. 3) The spatial evolution of settlements is related to natural conditions such as altitude, slope, aspect and distance from rivers, but social and economic factors such as economic development, per capita income, transportation conditions and policy measures have greater impacts. This study can provide a useful reference for standardizing and guiding rural construction in nature reserves.
Characteristics and Influencing Factors of Plankton Community Structure During Autumn in Xishan Island Waterway Network of Taihu Lake
LI Qing-zhuo, HUA Yue-zhou, DU Cheng-dong, HE Shang-wei, WU Zhao-shi, PAN Ji-zheng
2023, 39(2):  214-226.  doi:10.19741/j.issn.1673-4831.2021.0441
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To explore the characteristics of the plankton community in Xishan Island waterway network of Taihu Lake and its main influencing factors, 34 typical sampling points were investigated from October to November in 2020. The results show that a total of 68 species of phytoplankton belonging to 56 genera were identified. The main phyla was Chlorophyta (39.71%), followed by Bacillariophyta (30.88%) and Cyanophyta (13.24%). The average abundance of phytoplankton was 1.32×106 L-1, and Cyanophyta was the dominant phyla. Waterways in urban areas had the highest phytoplankton abundance, followed by waterways in agricultural areas and aquaculture areas. Moreover, 30 species of zooplankton belonging to 18 genera were identified, with the dominating species as Rotifera (76.67%). The average abundance of zooplankton was 113.93 L-1. Waterways in aquaculture areas had the highest zooplankton abundance, followed by waterways in urban areas and agricultural areas. The redundancy analysis revealed that oxidation-reduction potential, chemical oxygen demand, total nitrogen and ammonia nitrogen concentration were the main factors affecting the phytoplankton community structure. While water temperature, pH value, chlorophyll-a concentration, phytoplankton abundance and ammonia nitrogen concentration were the primary influencing factors to the zooplankton community structure.
Relationship between Phytoplankton Community Characteristics and Environmental Factors in Shibalianwei Wetland in Summer in Hefei, Anhui Province, China
HUANG Ruo-han, WANG Ting, SHANG Guang-xia, XIE San-tao, WANG Li-qing, ZHANG Wei
2023, 39(2):  227-235.  doi:10.19741/j.issn.1673-4831.2021.0666
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The estuary wetlands are important parts of the large-scale shallow lake systems, but the studies on their ecological status is limited. Shibalianwei wetland is a large-scale constructed wetland formed by "Returning Farmland to Wetland" Program. The wetland is located in the estuary area of Nanfei River flowing into Chaohu Lake. To investigate the relationship between water quality parameters and phytoplankton community characteristics, a total of 72 samples were collected from the Shibalianwei wetland in July 2018. The results show that:(1) According to the water quality index, the N and P content of the water bodies are high and in the range of moderate eutrophication level to severe eutrophication level. (2) 119 phytoplankton species, mostly small-sized algae, belonged to 7 phyla and 83 genera were found in the inside wetland with the dominant ones of Merismopedia sp., Aphanocapsa sp., Dictyosphaerium sp., and Crucigenia sp.; Comparatively, 85 species belonged to 63 genera and 7 phyla, mostly large-sized algae, were found in the waters outside the wetland with the dominant ones of Pseudanabaena sp., Aphanizomenon sp. and Microcystis wesenbergii. (3) The average density and biomass of phytoplankton in the inner wetland were 12 780.16×104 L-1 and 23.65 mg·L-1, while those in the outer wetland were 5 083.38×104 L-1 and 7.1 mg·L-1, respectively. (4) The results of canonical correspondence analysis (CCA) show that total nitrogen, ammonia nitrogen, soluble reactive phosphorus, electrical conductivity, water temperature, transparency, and aquatic plant coverage were significantly correlated with the distribution of phytoplankton (P<0.05); The results of the multiple regression tree analysis (MRT) show that the phytoplankton communities were significantly different when water transparency was above and below 29 cm. With the water transparency below 29 cm and the threshold of soluble reactive phosphorus (SRP) as 0.045 mg·L-1, the phytoplankton communities could further be divided into two significantly different clades. Variance decomposition analysis further show that the nutrient concentration in the water column was the main factor affecting phytoplankton community. The results of the study can provide new basic data for further understanding of the wetland ecology in large shallow lakes and the eutrophication management of Lake Chaohu.
Study on Cd Migration and Accumulation Characteristics and Influencing Factors of Soil-Dictyophora rubrovalvata System in Typical Karst Area of Guizhou
LIU Gui-hua, WANG De-mei, QIN Song, CHAI Guan-qun, LUOMU Xin-jian, FAN Cheng-wu
2023, 39(2):  236-243.  doi:10.19741/j.issn.1673-4831.2021.0644
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To explore the characteristics and influencing factors of the migration and accumulation of cadmium (Cd) in soil-Dictyophora rubrovalvata system in typical karst area, soil and Dictyophora rubrovalvata samples were collected. The contents of Cd and its occurrence forms in the soil, and the contents and bioaccumulation characteristics of Cd in Dictyophora rubrovalvata were analyzed, The factors affecting the migration and accumulation of Cd in the soil were discussed by principal component analysis. The results show that the total Cd contents of soil in the Dictyophora rubrovalvata planting area were between 0.24 and 4.23 mg·kg-1 and the average content was 0.96 mg·kg-1, which was 3.2 times that of the soil pollution risk screening value of agricultural land in GB 15618-2018 "Soil Environmental Quality Risk Control Standard for Soil Contamination of Agricultural Land (Trial)" and 1.45 times that of the soil background content value of Guizhou Province. The main form of Cd in soil was reducible (F2), and its relative content was 20.87%-63.81%, with an average value of 41.64%. The percentage contents of Cd in different forms were reducible state Cd (F2) > residual state Cd (F4) > weak acid soluble Cd (F1) > oxidable Cd (F3). The Cd contents of Dictyophora rubrovalvata ranged from 0.07 to 0.39 mg·kg-1 and the average content was 0.18 mg·kg-1 (in terms of fresh samples), lower than the standard value of GB 2762-2017 "National Standard for Food Safety:Limit of Pollutants in Food" (0.20 mg·kg-1), and the bioconcentration factor and translocation factor were 0.50-21.91 and 0.31-8.89, respectively. The pH value showed a negative correlation with the weak acid soluble Cd (r=-0.435, P<0.05, n=26), the Cd in Dictyophora rubrovalvata (r=-0.670, P<0.01) and the Cd accumulation coefficient of Dictyophora rubrovalvata (r=-0.724, P<0.01), whereas showed a positive correlation with the reducible Cd (r=0.469, P<0.05) and the soil total Cd concentration (r=0.392, P<0.05). The principal component analysis indicate that pH value, K, Ca, Fe and Cu contents were the main impacting factors to the enrichment of Cd in Dictyophora rubrovalvata.
The Effect of Soil Passivator on Heavy Metal Cadmium in Alkaline Farmland Soil and Its Accumulation in Wheat
LI Hong-liang, YUAN Cui, FU Yun-cong, ZHU Xiao-long, GUI Juan, LIU Dai-huan, DAI Qing-yun, HE Jun-qiang
2023, 39(2):  244-249.  doi:10.19741/j.issn.1673-4831.2021.0489
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Field experiments were performed to investigate the effect of passivator on heavy metal cadmium in alkaline farmland soil and its accumulation in different growing period of wheat. The results show that the addition of passivator could decrease the available Cd in alkaline farmland soil. In Cd contaminated soil collected from Xinxiang (DTPA-Cd 1.24 mg·kg-1), compared with the control experiment. By adding 0.20% (mass fraction) of the passivator, the available Cd content of the soil reduced by 28.09%-53.15% after 60-240 days; the Cd contents of the wheat root, stem and leaf were reduced by 43.20%, 53.00% and 53.00% after 140 days, respectively; the Cd contents of the wheat root, stem and leaf were reduced by 48.92%, 53.82% and 39.20% after 200 days, respectively; and the Cd contents of the wheat root, stem, leaf, and grain were reduced by 47.92%, 29.46% and 21.41% after 240 days, respectively. The results show that the passivator could decrease the available Cd content of soil and wheat, thus the Cd accumulation in different parts and different growing periods of wheat could be reduced. The contents of cadmium in wheat grain decreased from 0.22 to 0.09 mg·kg-1, which meets with the national standard (GB 2762-2017). It indicates that the passivator is a potential material for the remediation of heavy metal contaminated alkaline farmland soil.
β-sitosterol from Mirabilis jalapa Treated with Cadmium:Concentration Responses and Allelopathic Effects
ZHANG Wen-ting, WANG Hong-bin, WANG Hai-juan, PENG Yu, GUO Si-yu
2023, 39(2):  250-263.  doi:10.19741/j.issn.1673-4831.2021.0698
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Mirabilis jalapa, an alien invasive plant, can accumulate cadmium (Cd) and exert allelopathic effects to other plants. The detected sterols in M. jalapa will significantly affect seed germination and seedling growth of other plants. Although the allelopathic effects of M. jalapa on crops without heavy metal have been reported, few studies focus on the allelopathic effects in the coexistence of Cd. A hydroponic experiment was conducted at different Cd concentrations to determine the allelopathic effects of root exudates from M. jalapa on soybean and maize, the content of β-sitosterol in different parts of M. jalapa and its root exudates, and the allelopathic effects of exogenous β-sitosterol with different concentration (0, 0.125, 0.5, 1, 2 mg·L-1) on soybean and maize. The results show that with Cd stress, the allelopathic inhibition effect of root exudates from M. jalapa on soybean was stronger than that on maize. The content of β-sitosterol in the roots of M. jalapa was significantly higher than that in the stems and leaves. The content of β-sitosterol in the roots significantly reduced at high Cd concentration, while the content of β-sitosterol in the root exudates significantly increased. The seed germination and seedling growth of soybean and maize were significantly inhibited at the addition of 0.125 mg·L-1 β-sitosterol, but the seedling growth of maize was promoted by the addition of other concentrations of β-sitosterol. The seed germination and seedling growth of soybean were inhibited with different allelopathic degree. With the increasing concentration of β-sitosterol, the activities of superoxide dismutase (SOD) and peroxidase (POD) in leaves of soybean seedlings were firstly increased but then decreased. The content of malondialdehyde (MDA, a product of cell membrane lipid peroxidation) in soybean leaves was significantly higher than that of the control at the addition of 0.125 mg·L-1 β-sitosterol. However, the variation of MDA content in maize leaves was not significant. Comparatively, the activities of SOD and CAT in leaves of maize was increased. At low or high β-sitosterol concentration, the chlorophyll a and carotenoid contents in the leaves of the two crops were significantly decreased compared with the control. At Cd stress, the allelopathic inhibition of β-sitosterol on soybean was higher than that on maize. Therefore, the remediation of Cd-polluted soil by the intercropping of maize and M. jalapa is feasible.
Effects of Biogas Slurry Derived from Cow Dung on the Yield and Quality of Wheat and Silage Maize
YANG Yue, GONG Shao-shuo, JIN Hong-mei, YU Xiang
2023, 39(2):  264-272.  doi:10.19741/j.issn.1673-4831.2021.0652
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In order to investigate the effects of biogas slurry derived from cow dung on the yield and quality of wheat and silage maize, a field experiment was conducted in wheat and maize rotation system by different application rates. The effects of 100% biogas slurry nitrogen replacement (BS100) and 150% biogas slurry nitrogen replacement (BS150) on yield and quality indices of wheat and silage maize were studied by field plot experiment. The results show as follows:fresh weight of silage maize in all treatments increased significantly (P<0.05) with the increase of biogas slurry application after two years. The yield of silage maize in BS150 treatment reached 101.07 t·hm-2. After two years of continuous application of biogas slurry, the contents of crude protein and crude starch in wheat grains were significantly (P<0.05) increased with the increase of biogas slurry application level. The crude protein and crude starch contents in wheat grains under BS150 treatment were 14.24% and 78.40%, respectively. The crude protein content of silage maize were significantly increased (P<0.05) with the increase of biogas slurry application level. The crude fiber and crude fat contents of silage maize had no obvious change. The contents of Fe and Zn in wheat grains were significantly (P<0.05) increased. The highest Fe content and Zn content of wheat grains under BS150 treated were 22.09 and 20.53 mg·kg-1, respectively. The Fe content and Zn content of silage maize were decreased. Biogas slurry application did not increase the content of harmful metal Cd in crops, though it slightly increased the content of As in crops. The Cd and As content in crops did not exceed the limit value of pollutants in relevant standards. In conclusion, biogas slurry application did not reduce crop yield in wheat-maize system, and significantly improved crop quality, and did not increase the risk of accumulation of As or Cd in crops.