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Table of Content

Volume 35 Issue 1
25 January 2019
Table of Contents
Table of Contents
2019, 35(1):  0-0. 
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Analysis for Vegetation Degradation Factors in Opencast Coal Mines in Northern Grass-Land Area, China
YU Hao-chen, MU Shou-guo, BIAN Zheng-fu, HOU Jing, WU Ying-ju, WANG Xiao-yu, ZHOU Jia
2019, 35(1):  1-8.  doi:10.19741/j.issn.1673-4831.2018.0155
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The vegetation degradation in opencast coal mines is increasingly serious, which causes impacts on the environment. Therefore, it is of great significance to determine the main factors of vegetation degradation so as to implement precision prevention. Shengli and Pingzhuang coal mines were selected as study areas. Normalized difference vegetation index (NDVI) was employed to indicate vegetation degradation. The entropy weight was integrated with grey relational analysis to establish the entropy-grey relation model by which the relativity between NDVI and land excavation, land occupation, desertification and soil erosion were analyzed. The main factors of land degradation were determined based on the rank of relativity. The results show that:(1) The ranking of relativity of different factors in Shengli coal mine area is:land occupation (0.294 7) > desertification (0.155 5) > land excavation (0.151 0) > soil erosion (0.119 3); while in Pingzhuang coal mining area is:land excavation (0.169 3) > land occupation (0.163 7) > soil erosion (0.150 5) > desertification (0.103 4). (2) The main factors of vegetation degradation in opencast coal mines are land excavation and land occupation. (3) Although the factors of desertification and soil erosion have less impact on vegetation degradation than land excavation and land occupation, they should not be ignored. Some measures have been proposed based on the results, which could help to avoid blindness during the prevention of vegetation degradation.

Research on Remote Sensing Recognition and Monitoring Method of Coal-Covered Area Based on Spectral Characteristics: A Case Study of Xiaolongtan Mining Area
NI Heng, LI Xiao-shun, LU Yao, YAN Qing-wu, BIAN Zheng-fu
2019, 35(1):  9-15.  doi:10.19741/j.issn.1673-4831.2018.0178
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Facing the severe ecological problems brought by the increasing land degradation in the coal mining areas and the difficulties on the defining of the scope of coal-covered surface in the open-pit mining areas, a normalized difference coal mine index (NDCMI) was proposed based on the spectral characteristics of typical water bodies, vegetation, bare land and coal piles in the coal mining areas as well as the band characteristics of Landsat 8 remote sensing data. The NDCMI value of the ground object samples was used to set the threshold value to distinguish and identify the ground object information of the coal pile and the mining area. The results show that:First, consisting of blue, red, near-infrared and mid-infrared bands of Landsat 8, the NDCMI method was applicative to the Xiaolongtan mining area; Second, from 2013 to 2018, the area of the Buzhaoba open-pit mining area increased by 1.03 times, while the area of Xiaolongtan open-pit mining area decreased by 42%; The gravity of coal mining activities in Xiaolongtan mining area showed a spatial trend from northeast to southwest and the trend from Xiaolongtan open-pit mining area to Buzhaoba open-pit mining area, which greatly increased the pressure on ecology and environment of the Buzhaoba open pit mining area.

Effects of Soil Erosion of Accumulative Soil on the Migration of Heavy Metals in Dabaoshan Mining Area, Guangdong Province
CHEN San-xiong, ZHOU Chun-jian, XIE Jiang-song, SHU Ruo-jie, LIAO Jian-wen, CHANG Jin, ZHU Shi-hai, LI Hai-dong
2019, 35(1):  16-21.  doi:10.19741/j.issn.1673-4831.2018.0156
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The characteristics of soil and water loss and migration of heavy metals in accumulative soils with different ages in the Dabaoshan mining area of Guangdong were studied using in situ runoff experiments. The results show that:(1) The runoff of new spoil, old spoil, and natural soil all increased with time. The average runoff at 20 min was 6.52, 5.75 and 0.69 L·min-1, respectively. For the same time period, the average runoff of the new spoil and old spoil soils were much higher than those of natural soils; (2) The sediment concentration and rate of sediment yield of the new spoil and old spoils were higher than natural soils. The average sediment concentrations of new spoil soil and old spoil soil were 156.79 and 51.68 g·L-1, respectively, and the average rates of sediment yield were 0.99 and 0.27 kg·min-1, respectively. (3) The average contents of Cd in new spoil and old spoil soil erosion sediments were 11.43 and 11.20 times of that in natural soils, respectively, and the average loss rates were 361.67 and 135.33 times of that in natural soils, respectively; The average content and loss rate of heavy metals in the erosion soil of new spoil and old spoil were much higher than those in natural soil, and there was obvious "initial flushing" effect; The migration patterns of Pb, Zn, and Cu were similar to Cd; (4) There was a significant positive correlation between Cd, Pb, Zn and Cu content in runoff sediments and runoff. The loss rate of heavy metals was significantly positively correlated with runoff sediment content and sediment production rate. Runoff and sediment loss have a significant impact on the migration of heavy metals.

Bioaccumulation Characteristics and Risk Assessment of Heavy Metal Pollution in Tailing Wetland
HAN Rui-jie, QIU Rui-juan, REN Yi-chen, WANG Jian-ying, SI Wan-tong, ZHANG Xue-feng
2019, 35(1):  22-27.  doi:10.19741/j.issn.1673-4831.2018.0159
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In order to evaluate and quantify the pollution levels of heavy metals in tailings wetland, and to understand the biological enrichment characteristics of metals, the Tao'erwan wetland of Kundulun Reservoir was selected as the control site, and the water, sediment and toad Strauchbufo raddei were collected in the two wetlands respectively. The heavy metal contents of these samples were determined by inductively coupled plasma emission spectrometry, including toad's muscle, liver, skin and bone, and their consumption risks were assessed by the target risk factor. The results show that heavy metal contents in water and sediment of tailings wetland exceeded the standards to some extent. Cd, Cu, and Pb contents of toad livers in the two wetlands were significantly higher than that in other tissues. Cd and Pb contents of toad muscle in tailing wetland were higher than the National Standards for Food Safety (GB 2762-2017) and Pollution-Free Food Standard for Freshwater Fish (NY 5053-2005), and the risk factors of liver and bone were 4.22 and 1.15, respectively. This study indicated that in tailings wetland, water pollution was mild, and mainly was Cd, but the sediment pollution was heavy, especially for Zn and Pb. The Cu and Zn contents in tissues of toads was higher, and Cd, Cu, Zn, Pb were easily enriched in the liver. Among them, Cu content in toad liver could be used as a warning indicator of heavy metal pollution in the field of biological safety and ecological protection. Livers and bones of local amphibians Strauchbufo raddei poses some consumption risks, and should be given attention by relevant authorities.

Lake Sediment Evidences Historical Patterns of Lake Ecosystem Services and Their Tradeoff/Synergy Mechanism: Progress, Case Studies and Prospective
DONG Xu-hui, XU Min, LIN Mei-zhen, LI Yan, YANG Xiang-dong
2019, 35(1):  28-37.  doi:10.19741/j.issn.1673-4831.2018.0135
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Understanding the spatio-temporal process and tradeoff/synergy mechanism of ecosystem services (ES) has been a research hotspot, given its important role in enhancing the overall ecological benefits and human welfares. The methodology for establishing the pattern, process and drivers of such ES tradeoff/synergy over large spatio-temporal scale and current research status has been reviewed. It took Taibai Lake (29°56'-30°01' N,115°46'-115°51' E) in Hubei Province, China, as an example, to illustrate how to combine historical and paleolimnological records to quantify the process and reveal the tradeoff/synergy pattern of various ES. It clearly illustrated that primary production and biodiversity (supporting services) have increased (synergies), whereas climate and water purification (regulating services) have significantly decreased (tradeoffs) since the 1950s when attempts were made by the local population to reach a higher land/food ES level. The advantage of paleolimnological approach in understanding the long-term pattern of ES is highlighted. Finally, current limitation is indicated and following future research directions on this issue are proposed:to minimize the uncertainty of paleolimnological proxies; to make more effort on modelling the dynamic process between the ecosystem and service deliverary under multiple scenarios; to conduct more research on the lake ES tradeoff/synergy process across various spatio-temporal scales.

Spatial Distribution, Sources and Risk Assessment of Polycyclic Aromatic Hydrocarbons in a Rapid Urbanization City: Shenzhen
ZHAO Han, ZHAO Jun, XU Xiao-ye, WU Shao-hua, ZHU Qing
2019, 35(1):  38-45.  doi:10.19741/j.issn.1673-4831.2018.0207
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Urbanization and its environmental impact are important topics in global environmental change. In this study, 93 urban soil samples from different land-use types in Shenzhen, China, were used to investigate the spatial and temporal analysis of PAHs content, components and sources in Shenzhen urban green space. High spatial resolution mapping was conducted to assess the environmental and health risks of PAHs in urban green spaces. The results show that the total PAHs contents in the surface soil of the main Shenzhen urban area were between 73.47-2 309.88 ng·g-1, with an average of 494.34 ng·g-1. The total content of seven carcinogenic PAHs was between 24.45 and 1 274.96 ng·g-1, with an average of 257.35 ng·g-1, accounting for 52.1% of the total PAHs. In the spatial distribution, the PAHs content was highest in industrially dense areas, followed by population and traffic-intensive areas, and the PAHs content was lowest in areas with a large proportion of green spaces. The PMF model show that coal-fired high-temperature combustion and traffic exhaust emissions were the main sources of surface PAHs in the main urban areas of Shenzhen. ILCRs and CR in different exposure approaches was less than 10-6 for both children and adults, indicating that the soil environmental quality in Shenzhen was generally good, but the maximum carcinogenic risk for children and adults reached 10-6 in some locations, which indicates potential health risks. The prevention and control of urban soil pollution needs to be taken seriously to ensure the coordinated development of urban economy and ecological environment.

Environmental Impact Analysis Derived From Nitrogen and Phosphorus Flows of the Residents' Agri-Products Consumption System
HUANG Li, WU Hui-jun, WEI Kai-ping, WANG Xiao-xu, CHEN Xiao-fang
2019, 35(1):  46-54.  doi:10.19741/j.issn.1673-4831.2018.0256
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The environmental impacts caused by nitrogen and phosphorus flows of the residents' agri-products consumption system has become serious. Based on life cycle assessment (LCA), a model of the environmental impacts derived by nitrogen and phosphorus flows of the residents' agri-products consumption system was conducted, which includes crop primary processing, livestock slaughtering, rural agri-products consumption, and urban agri-products consumption. With the model, four environmental impacts including phosphorus depletion, climate change, acidification and eutrophication caused by the nutrient flows of residents' agri-products consumption system in Anhui Province in 2015 were characterized. The environmental impacts contributed by different subsystems were also compared by using the model. The results show in agri-products processing, wheat and pig contributed the most phosphorus depletion and eutrophication, which were 43.05% and 41.48%, respectively. Meanwhile, grains consumed by both urban consumption and rural consumption had the largest phosphorus depletion, which were 51.09% and 65.22%, respectively. Moreover, rural residents' manure resulted in the most eutrophication and acidification, which were 91.05% and 99.49%, respectively. While the rural solid waste generated the greatest portion for global warming (77.76%). Thus, improving processing technology, changing diet structure, and strengthening the disposing of rural wastes (including manure, domestic sewage, and solid waste) are the efficient measures of mitigating the environmental impacts caused by the nutrient flows of residents' agri-products consumption.

Construction of Landscape Ecological Security Pattern of Shengli Coalfield in Inner Mongolia Based on the Minimum Cumulative Resistance Model
HUANG Xin, CAO Xue-zhang, ZHANG Ming, ZOU Xian
2019, 35(1):  55-62.  doi:10.19741/j.issn.1673-4831.2018.0119
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Shengli Coalfield is an important coal base in China. However, it had undergone serious degradation of the ecological environment in this region due to the large-scale exploitation of coal resources. The GF1 images in 2016 were manually interpreted to generate a landscape type map on the basis of the landscape classification in Shengli Coalfield. The landscape ecological security pattern in Shengli Coalfield was constructed by using the minimum cumulative resistance model, which including the identification of ecological sources, ecological corridors and ecological nodes. Source identification was carried out by selecting the highest quality patches as ecological sources based on the evaluation of landscape quality. The resistance surface was generated with the landscape self-factors and adjacent landscape disturbance factors. The ecological corridors were extracted by using the minimum cumulative resistance model. Ecological nodes were identified by combining the maximum cumulative resistance "ridge line", which was extracted on the minimum cumulative cost distance surface under hydrological analysis model, with ecological corridors. Landscape ecological security pattern in Shengli Coalfield is composed of 10 ecological sources, 24 ecological corridors and 29 ecological nodes. Ecological protection and restoration of ecological sources, ecological corridors and ecological nodes should be strengthened so as to improve regional ecological stability.

Analysis on Genetic Diversity and Genetic Structure of Camellia nitidissima by AFLP Technology
LI Xin-lei, WANG Jie, YIN Heng-fu, FAN Zheng-qi, LI Ji-yuan
2019, 35(1):  63-68.  doi:10.19741/j.issn.1673-4831.2018.0236
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To provide the scientific basis for effective protection and efficient utilization of Camellia nitidissima resource, amplified fragment length polymorphism (AFLP) technology were used to study the genetic diversity and genetic structure of the four natural populations of C. nitidissima. The result show that 1 619 DNA loci were obtained using eight primers, of which, 1 473 loci were polymorphic, and the percentage of polymorphism was 90.98%. The gene diversity and Shannon's information index were 0.146 and 0.246, respectively, at specific level, and that were 0.131 and 0.215 at population level. The change trends of percentage of polymorphic loci, gene diversity and Shannon's information index of four C. nitidissima populations were uniform. The percentage of polymorphic loci ranged from 56.83% to 72.11%. The gene diversity index ranged from 0.122 to 0.138, and the Shannon's information index ranged from 0.197 to 0.228. The genetic differentiation coefficient of C. nitidissima populations was between 0.139 and 0.289, that shows the genetic variation of C. nitidissima was mainly within the populations. The analysis of molecular variance (AMOVA) showed 81.52% of the genetic variation was within the populations, and 18.48% of that was among the populations. The genetic variation of C. nitidissima was mainly within the populations. The unweighted pair group method with arithmetic mean (UPGMA) indicates that there was no significant correlation between the genetic variation of C. nitidissima populations and the geographic distance. Conservation strategies including in situ preservation for promoting natural populations regeneration and ex situ preservation of populations have been put forward.

Soil Quality Assessment of Kiwifruit Field Using MDS Method in Zhouzhi County
ZHANG Fu-ping, GAO Zhang, LI Xiao-juan, NIE Shuo, LI Ling, LIU Jie-yao
2019, 35(1):  69-75.  doi:10.19741/j.issn.1673-4831.2018.0041
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Zhouzhi County is an important kiwifruit production base in Shannxi Province and even China. The soil quality seriously affects the quality and yield of kiwifruit. 18 indexes were selected based on comprehensive analysis the soil physical and chemical properties in kiwifruit orchard. Then the minimum data set (MDS) method was used to evaluate the soil quality of different planting years and the whole kiwifruit orchard. As a result, 9 soil indexes (total porosity, total phosphorus, available nitrogen, Mg2+, total kalium, organic matter, water content, available phosphorus and physical clay) were suitable to soil quality assessment in study area selected into MDS. With the increasing of kiwifruit planting year, soil quality showed the trend of increase-stabilization-increase. The soil nutrients contents, such as organic matter, total nitrogen, total potassium, available nitrogen and available phosphorus were the restriction factors for soil quality, and those showed a weight ratio value of 53%. Moreover, the soil nutrient content was generally low in the study area. The results also showed that the soil porosity and ventilation were gradually decreased with planting year increasing, and may lead to soil consolidation. To improve the quality and yield of kiwifruit, it is necessary to improve soil nutrient quality, adjust fertilization structure and improve soil structure.

Effects of Cadmium Stress on Rice Growth and Correlation Between Bleeding Sap and Cadmium Content in Rice
PENG Ou, LI Dan-yang, LIU Shou-tao, LUO Hai-yan, WEI Xiang-dong, YE Chang-cheng, LIU Xiao-li, TIE Bai-qing, CHEN Wen-yan
2019, 35(1):  76-82.  doi:10.19741/j.issn.1673-4831.2018.0104
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The effects of cadmium (Cd) stress on growth of rice and the correlation between the Cd in bleeding sap and rice were studied by considering the actual situation of Cd pollution in rice in China, which will provide data support and scientific guidance for the safety of rice production in Cd-contaminated areas. Effects of different Cd concentrations (0, 10, 50, 200, 500 and 1 000 μg·L-1) on the growth of two rice varieties (Zhongjiazao No. 17 and Taiyou No. 390) and correlation between Cd content in different parts of rice and the brown rice were studied under nutrient solution culture condition. Results show that positive effect of Cd on rice growth was detected at the treatment with a Cd concentration of ≤ 10 μg·L-1 and no significant difference (P>0.05) was found between the Cd-treated smples and the control. The growth of rice was inhibited at Cd concentration of >10 μg·L-1 and the inhibitory effect was increased with the increase in Cd concentration. The Cd content in each part of rice was also increased with the increase in Cd concentration, and the change of Cd content in bleeding sap was consistent with that in each part of rice plant. Significant correlation (P<0.01) was detected between Cd content in the bleeding sap and brown rice. And the Cd content in the bleeding sap at tillering stage could be used to predict the degree of Cd contamination of rice.

Isolation, Identification and PAH-Degrading Performance of an Endophytic Bacterium Enterobacter sp. PRd5
TAO Jia-yu, HONG Ya-jun, CHEN Xue-mei, LIU Wen-tao, ZHU Xue-zhu, MIAO Ya-hui
2019, 35(1):  83-90.  doi:10.19741/j.issn.1673-4831.2018.0112
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Endophytic bacteria with PAH-degrading ability have shown great potential in reducing the PAH contamination in soils and plants. In this study, eight pyrene-degrading endophytic bacterial strains, belonging to Enterobacter sp., Chitinophaga sp., Xanthomonas sp. etc, were isolated from the inner plants growing in PAH-contaminated sites. The degradation rates of pyrene (50 mg·L-1) by these strains ranged from 7.59% to 45.50% after 10-day cultivation under 30℃ and 150 r·min-1. Having great potential in pyrene degradation, strain Enterobacter sp. PRd5 was selected as the representative for systematical investigation of its pyrene biodegradation ability under different culture conditions. The results show that 41.37%-50.63% of pyrene could be removed by Enterobacter sp. PRd5 from media after 10-day cultivation at 30℃ and 150 r·min-1. More than 95% of naphthalene (500 mg·L-1), fluorine (100 mg·L-1), and phenanthrene (50 mg·L-1), which are 2-3 ringed PAHs, were removed by Enterobacter sp. PRd5 after 7-day cultivation. Remarkably, 35.89% of fluoranthene (50 mg·L-1) and 17.44% of benzo[a]pyrene (10 mg·L-1) were removed by Enterobacter sp. PRd5 from the media after 10-day cultivation, suggesting that strain PRd5 has great capability of degrading 4-5 ringed PAHs. Furthermore, the study indicate that pH value of 6.0-8.0, temperature of 25-35℃, ρ(NaCl) ≤ 10 g·L-1, inventory 10-30 mL·(100 mL)-1 flask, 3%-17% inoculation quantity, initial pyrene concentration of 25-50 mg·L-1, and 100 mg·L-1 additional glucose are favorable for pyrene biodegradation by Enterobacter sp. PRd5.

Upgrading Semi-Continuous Mesophilic Anaerobic Digestion of Waste Activated Sludge by Combined Ultrasonic, Thermo-Alkaline Pretreatment
XU Hui-min, QIN Wei-hua, LI Zhong-lin, GU Qi, DAI Xiao-hu
2019, 35(1):  91-97.  doi:10.19741/j.issn.1673-4831.2018.0056
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Semi-continuous mesophilic anaerobic digestion assays were performed to assess the influence of combined ultrasonic, thermo-alkaline pretreatment on biodegradability of waste activated sludge (WAS). The pretreated WAS was obtained at optimal conditions of temperature 73℃, alkaline dosage 0.085 g·g-1 total solids (TS) and specific energy 9 551 kJ·kg-1 TS. During anaerobic digestion, the average daily methane production of pretreated WAS was as high as 234 mL, which was 1.94 times that of untreated WAS. Furthermore, modified-Gompertz model was introduced to predict the methane production and evaluate the kinetic parameters. The modified-Gompertz models (R2:0.998 and 0.993 for pretreated and untreated WAS, respectively) show good fit to the experimental results. For pretreated WAS, kinetic constants of methane production model using modified-Gompertz were P (methane production potential, 5 376.4 mL), Rm (maximum methane production rate, 394.8 mL·d-1), λ (minimum time to produce methane, 2.8 days). Besides, the ratio of methane conversion of pretreated WAS achieved at 82.17%. During anaerobic digestion, concentrations of soluble chemical oxygen demand (SCOD), soluble protein (SP), and soluble carbohydrates (SC) of pretreated WAS were much higher than that of the untreated WAS. Therefore, the reductions of total suspended solids (TSS) and volatile suspended solids (VSS) were 54.9% and 61.8% for pretreated WAS after pretreatment and anaerobic digestion. Based on results obtained above, it is suggested that combined ultrasonic, thermo-alkaline pretreatment improves sludge disintegration as well as increases biodegradability, resulting to anaerobic digestion enhancement.

Study on Performance Anaerobic Mono-digestion/Co-digestion of Different Agro-industrial Wastes Using Chicken Feces as Main Substrate
CHEN Xu, YAN Yong-qing
2019, 35(1):  98-105.  doi:10.19741/j.issn.1673-4831.2018.0253
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The methane production potential and kinetic features of anaerobic digestion/co-digestion of five different agro-industrial wastes including chicken feces, food waste, cheese whey, corn stover and hay grass were studied in batch mode. With various VS contents of 2%, 3%, 4% and 5%, the maximum methane production potentials obtained during batch tests from high to low were cheese whey, food waste, corn stover, hay grass and chicken feces. The corresponding maximum cumulative methane production could be achieved to be 1 270.9 (5%), 1 113.6 (5%), 646.7 (2%), 645.0 (2%) and 364.7 mL·g-1 (4%) VS, respectively. The experimental results obtained from anaerobic digestion of different agro-industrial wastes could be well fitted to modified Gompertz model (R2=0.961-0.990), indicating that modified Gompertz model is suitable for evaluating the characteristics of anaerobic digestion of single substrate in this study. The predictive values were able to be used to evaluate the feasibility of anaerobic co-digestion of chicken feces with other substrates. Based on the predictive values from modified Gompertz model, the anaerobic co-digestion tests were designed and undertaken by blending chicken feces as main substrate with one, two or three other kinds of substrates among cheese whey, corn stover and hay grass. The optimized C/N ratio could effectively decrease lag phase and improve methane production potential of anaerobic digestion of chicken feces. Methane production was improved by 52.2%-112.9%, compared with that of anaerobic mono-digestion of chicken feces. The highest methane production potential was observed at a C/N ratio of 28.02 with 50% chicken feces and 50% cheese whey.

Spatial-Temporal Variation of Distribution of Rainfall Erosivity in the Poyang Lake Basin During 1961-2014
ZENG Yu, LI Sha, HU Yu-bin
2019, 35(1):  106-114.  doi:10.19741/j.issn.1673-4831.2018.0121
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Rainfall erosivity reflects the potential ability of soil erosion caused by rainfall, which is the core of soil erosive risk assessment. The spatial-variations of rainfall erosivity in the Poyang Lake Basin were investigated based on daily rainfall data during 1961-2014. Results show that average value of rainfall erosivity was 9 537.9 MJ·mm·hm-2·h-1, and had an insignificant upward trend. Rainfall erosivity and its tendency rate increased from southwest to northeast of Poyang Lake Basin, but the trend for most of the stations was insignificant. The annual average value of concentration degree of the rainfall erosivity was 0.49 with an insignificant decreasing trend, while annual average concentration period was 152.4° (corresponding to June) with an insignificant increasing trend. Spatial distribution of concentration degree was similar to rainfall erosivity, while concentration period had no obvious distribution pattern in the Poyang Lake Basin. Spatial pattern of rainfall erosivity did not change in the recent six decade while the centre of the high (low) value area changed in different decades. Dynamic of concentration degree for the last six decade was in accord with rainfall erosivity, while concentration period had no evident distribution pattern.

Research on Changes of Rural Farming Landscape Based on Villagers' Memories
WANG Xiao-jun, TIAN Jin-jia, ZHANG Xiao-tong, YU Lin-jun, DUAN Jin-ming
2019, 35(1):  115-120.  doi:10.19741/j.issn.1673-4831.2018.0265
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The transformation of rural China by the adoption of western agricultural farming practices has radically altered rural ecosystems. In little more than half a century, traditional rural landscapes were rapidly industrialized with unforeseen outcomes for essential life support systems. The principal witnesses to this rural revolution were farming communities throughout China. This research project employed the field case study method in Duimenshan Village in Guizhou Province to document and analyze rural transformations since 1949. Local experience, oral histories and geographic changes were documented using participatory rural appraisal (PRA) and digital imaging technology including 3D e-Sandbox. The results show that:over the past 60 years, modern agricultural production elements have continuously invaded into the traditional farming system of the village. So far, traditional farming landscape has been replaced by modern agricultural landscape rapidly. The landscape of paddy fields formed by rice planting in the village has been gradually replaced by non-irrigated landscape formed by economic crops with higher market value such as tobacco and Job's tears. Due to the continue replacement of the space with grain crops by economic crops, economic crops are now the major crops in the village instead of grain crops. Moreover, the varieties of grain crops have turned from traditional cultivars to hybrid varieties. The traditional cultivars have almost disappeared nowadays. The industrialized model of agricultural production has gradually replaced the traditional sustainable farming pattern driven by economic interests, causing the changes of the farming landscape in the village. The consequences for food safety and the integrity of water and soil ecosystems were not adequately considered. Our research raises important questions whether the ecological sustainability of rural resources, the health of farming communities, their long term economic viability, and traditional cultural heritage values are being sacrificed for short term economic gains.

Effects of New Microelement Foliar Fertilizer on Flag Leaf Senescence, Grain Yield and Quality of Spring Wheat
ZHANG Chun-ming, LAN Ru-jia, GAN Chun-dan, GUAN Yong-xiang, ZHAO Hai-yan, JIANG Ping-an, ZHENG Qing-song
2019, 35(1):  121-127.  doi:10.19741/j.issn.1673-4831.2018.0216
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In order to investigate the effects and mechanism of new foliar fertilizer on crop yield and quality, spring wheat (Yangmai 16) was as the experiment material. By applying foliar fertilizer with different dose and times, contents of chlorophyll (Chl), soluble protein (SP), malondialdehyde (MDA) and activities of antioxidant enzymes in flag leaves were studied, and the grain yield and quality were also determined. The results show:contents of Chl and SP, activities of superoxide dismutase (SOD), ascorbate-peroxidase (APX) and glutathione reductase (GR) in flag leaves were all increased under spraying fertilizer, and MDA contents in flag leaves were decreased significantly. Foliar fertilizer spraying increased 1 000-grain weight, grain yield, also increased protein content, wet gluten content, sedimentation and stabilization time of grain. However, these above-mentioned effects were more obvious when fertilizer spray was combined with carbendazim, and these differences all did not reach significant level (P>0.05). There was no significant difference in yield and quality between spraying twice and once (P>0.05). Thus, foliar fertilizer application at flowering or heading stage can prevent leaf senescence and improve chlorophyll content by increasing the leaf antioxidation, and enhance grain filling, grain yield and quality.

The Study of Diversity of Culturable Bacteria Community in Manure From Large-scale Dairy Farms in Yinchuan
ZHANG Wen, MA Chen-jie, LI Wu, ZENG Jin, DENG Guang-cun, WU Xiao-ling
2019, 35(1):  128-135.  doi:10.19741/j.issn.1673-4831.2018.0169
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The present study aims to investigate the culturable bacteria community of isolates from 4 kinds of samples (fresh fecal samples, accumulated manure without treatment samples, soil samples and waste water samples) collected from 3 large-scale dairy farms in Yinchuan. The samples were first diluted and plated on 8 different kinds of separation media such as nutrient agar medium, blood agar medium and MacConkey agar medium. Each of the single colony was then purified at least 3 times with the corresponding media for further analysis. After Gram staining, each isolate was further identified by VITEK 2 Compact automatic microbial biochemical identification system or 16S rDNA gene sequencing analysis. A total of 429 isolates were obtained from the samples through isolation and purification. After further analysis with VITEK 2 Compact automatic microbial biochemical identification system and 16S rDNA gene sequencing, a total of 358 strains were identified, these strains were distributed in 4 phyla, 6 classes, 15 orders, 23 families, 39 genera and 102 species. The rates of pathogenic bacteria in the samples were also calculated. Results show that conditional pathogenic bacteria accounted for 88.55% (317/358) of the total. The main conditional pathogens in the strains were S. aureus (11/358), E. coli (33/358) and S. thoraltensis (8/358). Strains mainly concentrated in the Firmicutes, Actinobacteria and Proteobacteria, and the conditional pathogenic bacteria may seriously threaten the human and animal as well as environmental if these fecal samples are discarded or used as fertilizer without proper treatment.