Table of Content

Volume 36 Issue 9
25 September 2020
Table of Contents
2020, 36(9):  0-0. 
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Monitoring Human Activities in Jiaozi Mountain Nature Reserve Based on Remote Sensing During 1992-2018
ZHANG Ming-sha, LIU Qian-fei, WANG Jing-wen, CAI Ying, BAI Zhi-gang, YE Jiang-xia
2020, 36(9):  1097-1105.  doi:10.19741/j.issn.1673-4831.2019.1002
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Using satellite remote sensing technology to monitor human activities in nature reserves has advantages of being real-time, efficient, objective and accurate. Remote sensing images can be used to interpret and extract the degree of human interference and its spatial-temporal distribution patterns, thus problems existing in management and protection can be discovered and evaluated timely to support the decision-making practice of local management, which is of great significance for scientifically evaluating and improving the effectiveness of management and conservation in nature reserves. Taking multi-time period Landsat and high-resolution satellite imagery as data sources, the human activities of Jiaozi Mountain nature reserve in 1992, 2000 and 2018 were extracted, including the residential area, farmland, transportation land, other construction land, and tourism land. Subsequently, the temporal and spatial patterns of human activities were analyzed with land cover transfer matrix and disturbance index. The results show that (1) The human disturbance in the nature reserve during each period changed to some extent, and the area ratio fluctuated from 1.563% in 1992 to 2.191% in 2000 and then fell to 1.412% in 2018. (2) Types and intensity of human disturbance dynamically varied over time with residential area and farmland dominated in 1992 and the ratio of tourism land, transportation land and other construction land increased in 2018. The human impact index increased from 6.64×10-4 in 1992 to 7.90×10-4 in 2000 and then decreased to 6.80×10-4 in 2018. (3) The spatial patterns of human activities showed dynamic changes over time. During 1992 and 2018, there was still a small number of human activities in the core area, with obviously decreasing in the buffer zone and gradually expanding to the experimental area. The findings implied that the area of human activities and disturbances have been reduced overall since the nature reserve under different managing levels of municipal in 1992, provincial in 2000, and national in 2018. However, human interference is still severe in the nature reserve, the development of tourism and agriculture in recent years accounts for the main driving factors.
Spatio-temporal Change and Driving Factors of Integrated Ecological Risk of Catchments in Karst Mountainous Area of Guizhou Province From 2000 to 2018
XI Shi-jun, CAI Pei-ling, AN Yu-lun
2020, 36(9):  1106-1114.  doi:10.19741/j.issn.1673-4831.2019.0775
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Due to the fragile ecological background, soil erosion, rocky desertification and other environmental problems in Karst mountainous areas, the contradiction between people and land in the basin is prominent, and the economic development is seriously restricted. On the basis of comprehensively considering the ecological risk for the process of the landscape succession, soil erosion and rocky desertification of Karst mountain areas, the evaluation model of integrated ecological risk of the basin was constructed to evaluate and analyze the spatio-temporal evolution characteristics of integrated ecological risk of watershed from 2000 to 2018, with 324 small catchments in the Wujiang Basin of Guizhou province as evaluation unit, and used the geographical probe to detect the spatial drivers. The results show that: (1) The landscape pattern of the Basin changed significantly from 2000 to 2018, in which the area proportion of forest land, grassland, artificial surface and wetland increased by 2.87, 1.10, 0.49 and 0.21 percent, respectively, and the one of cultivated land continued to decrease by 4.7 percent. (2) The average value of integrated ecological risk was 0.58, 0.61, 0.66, 0.31 and 0.34 in 2000, 2005, 2010, 2015 and 2018, respectively, and the overall ecological risk of the basin was on the decline. The ecological areas of higher risk were mainly distributed in the upper and lower reaches of basin, while the ones of lower risk were distributed in the middle reaches. (3) The explanatory power of human activity factors such as the interference degree and the spatial distribution of population density and GDP were greater than that of natural factors, among which the explanatory power of human interference factors was the highest (38.00%-83.00%). Human activity factors are the main driving factors for the dynamic change of integrated ecological risk. The results of the study are referenciale value for the sustainable management and development of the social-economic-ecological environment system in Wujiang Basin.
Delimitation of Urban Growth Boundaries Based on Ecosystem Service Value: A Case Study of Hengyang Central Area
HUANG Fu-qiang, WANG Zhi-yuan, LIU Hui, QI Zeng-xiang, WU Xin-xin
2020, 36(9):  1115-1125.  doi:10.19741/j.issn.1673-4831.2019.0887
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An urban growth boundary policy is an important tool for integrating urban development and regional ecological protection plans. Incorporating the ecosystem service value of land into the urban planning process can help to implement the national strategy for ecological civilization in China. Previous delimitation mechanisms in studies of urban growth boundaries have rarely taken the ecosystem service value of land into account. Therefore, we designed a mechanism that combines an ecological security pattern (based on 2005-2015 data from ecosystem service value evaluations) with the future land use simulation (FLUS) model to delimitate the urban growth boundary in the Hengyang central area. It is found that: (1) the total ecosystem service values decreased from 2.571 billion yuan to 2.475 billion yuan from 2005 to 2015, the value of hydrological regulation and water supply service functions showed an upward trend, whereas the other ecosystem service values showed a downward trend; (2) 17 325.72 hm2 of urban rigid growth boundary is distributed along the Xiangjiang River and its tributaries, Zhengshui and Leishui, and has formed a "three corridors and three pieces" space structure; (3) the area of urban elastic growth boundary in 2030 is projected to be 20 238.57 hm2 and will be distributed as "one central area and multiple groups" with the ecological land in the study area more protected in 2030 than today; (4) an increase of 0.061 billion yuan in ecosystem service value indicates that given the limited development of the Hengyang central area, ecosystem service functions will help to maintain its regional ecosystem services and develop its regional ecological security. These results indicate that the delimiting mechanism used to study urban growth boundaries can scientifically evaluate the ecological cost of urban expansion and effectively resolve the contradiction between urban development and ecological protection. Thus, these findings provide a foundation for urban master planning, ecological protection planning, and national territory development planning.
On the Assessment Methodology for Potential Loss Caused by Alien Organism: A Case Study of Alien Epidemic Stalk-based Ulcer Disease of Rapeseed
LU Zhong-shan, WU Xin-hua, LI Bin, ZHOU Ming-hua, WANG Ying, ZHOU Shu-dong
2020, 36(9):  1126-1132.  doi:10.19741/j.issn.1673-4831.2019.0642
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In this paper, an alien epidemic stalk-based ulcer disease of rapeseed was used as an example to propose an assessment methodology for the potential loss caused by an alien organism of unsuccessful invasion. According to the GARP niche model based on ArcGIS raster data map, the distribution areas of each adaptable variety in the provinces surveyed were extracted by the mask tool-Extract By Mask. The construction of an assessment model for the potential loss was attempted, that is, an assessment methodology for the potential loss caused by alien invasive organism was constructed from three aspects: potential direct economic loss (loss of agricultural output value, loss of agricultural and sideline food processing industry, prevention and control costs), potential indirect economic loss (rapeseed tourism industry) and potential non-economic loss (loss of ecosystem function). This research shows that the total potential loss of stalk-based ulcer disease of rapeseed was estimated at as high as 9.605 billion RMB, and the potential direct economic losses, potential indirect economic losses, and potential non-economic losses accounted for 54.9%, 36.0%, and 9.1% of the total potential losses, respectively. This research concluded that animal and plant quarantine plays an important role in preventing the invasion of alien organisms.
Evaluation and Prediction of Nitrogen Resources Sustainable Utilization Based on the DPSIR Model in Quzhou County
WANG Fang-fang, WANG Yan-hua, CAI Zu-cong, HUANG Yu
2020, 36(9):  1133-1140.  doi:10.19741/j.issn.1673-4831.2019.0714
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Environmental problems in northern China due to low nitrogen use efficiency have become increasingly prominent. Taking the DPSIR (drive force-pressure-state-impact-response) model as frame, 38 indexes were selected to set up the index system of the evaluation for nitrogen resources sustainable use combining with the statistics of Quzhou County from 1997 to 2017. The sustainable utilization level of nitrogen resources in Quzhou County was evaluated, and a grey prediction model was used to predict the sustainable development trend of nitrogen resources in the study area. The results show that from 1997 to 2017, the driving force, state and influencing factors of nitrogen use evaluation values all increased, while the evaluation value of pressure factors decreased, and the evaluation values of response factors decreased first and then increased. The nitrogen resource system of Quzhou County generally developed from weak sustainable to basic sustainable development under the joint influence of multiple factors. The grey prediction model predicte that the sustainable use of nitrogen resources will be on the rise in the period of 2018-2030. The results of the scenario simulation indicate that the urbanization rate, per capita GDP, per capita net income of farmers, and per capita disposable income of urban areas could increase the comprehensive evaluation value of sustainable utilization of nitrogen resources in Quzhou County by 10%. In the process of economic development and urbanization of Quzhou County, the planting area of economic crops and the investment in treatment facilities should be increased to promote the recycling of waste nitrogen in the household consumption system, so as to maintain a high level of nitrogen resources sustainable utilization in Quzhou County.
Will Livelihood Capital Affect Farmers' Organic Fertilizer Application Behavior?
WANG Xuan, ZHANG Jun-biao, HE Ke
2020, 36(9):  1141-1148.  doi:10.19741/j.issn.1673-4831.2019.0784
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Ecologically protecting farmland soil is an effective way to ensure the quality of agricultural products and to enhance the capacity for agricultural sustainable development. Based on 998 microcosmic survey data in rural Hubei Province in 2017, this paper explores the effects of livelihood capital on farmers' organic fertilizer application behavior from the perspective of family life cycle. Binary Probit model is employed. Results show that: (1) Financial capital, natural capital, material capital and social capital are 4 components of livelihood capital that are significantly influencing farmers' behavior of organic fertilizer application. (2) The family life cycle variable has a significant effect on farmers' organic fertilizer application behavior. Compared with farmers at the initial stage, those farmers at the maintenance period, the burden period, the stable period and the "empty nest" period are more likely to apply organic fertilizer. (3) With farmers at different family life cycle stages concerned, the financial capital and natural capital mainly affect farmers' organic fertilizer application behavior at the maintenance period, the material capital mainly influences farmers' organic fertilizer application behavior at the burden period or the "empty nest" stage, the social capital mainly affects those at the maintenance period, the burden period or the stable period, while the human capital mainly influences farmers' organic fertilizer application behavior at the burden period and the support period. Based on the above results, some specific suggestions are put forward to different types of farmers for promoting their willingness on organic fertilizer application for agricultural green production.
Dynamic Study of Waterbird Diversity in the Kangshan and Duchang Reserves on Poyang Lake
ZHI Yi-jin, LIU Wei, SHAO Ming-qin, YI Jian-feng
2020, 36(9):  1149-1153.  doi:10.19741/j.issn.1673-4831.2019.0857
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The diversity of waterbirds in a sample area within the Kangshan migratory bird nature reserve (Kangshan) and Duchang migratory bird nature reserve (Duchang) on the Poyang Lake was investigated using a direct count method between 2017 to 2019. A total of 159 701 individual waterbirds belonging to 48 species, 7 orders, and 12 families were recorded, including 37 species with 38 074 individuals in Kangshan and 41 species with 121 627 individuals in Duchang. Of the species identified, five are listed as China's first-class national protected animals including the scaly-sided merganser (Mergus squamatus), Siberian crane (Grus leucogeranus), hooded crane (Grus monacha), oriental white stork (Ciconia boyciana), and black stork (Ciconia nigra). Another five species are listed as second-class national protected animals. Variation in the distribution of national protected bird species and main bird groups was detected in Kangshan and Duchang, indicating that these two reserves have their own important role in bird conservation. A total of 10 dominant species were recorded in Kangshan and Duchang. Members of the Anatidae and Scolopacidae were the most abundant species. Between 2017 and 2019, eight dominant species belonging to the Anatidae and Scolopacidae were recorded in Kangshan and only three dominant species belonging to the Anatidae were recorded in Duchang. The species number, number of individuals, and community dominance were lower in Kangshan than in Duchang, but the diversity index and evenness index were higher in Kangshan than in Duchang. This difference can be explained by the micro-habitat variation between the two regions. Based on the differences in waterbird species in the two reserves, it could be concluded that Kangshan and Duchang have complementary advantages in ecological functions that are important for the conservation of national protected waterbirds and dominant species.
Responses of Litter Production and Its Quality in a Casuarina equisetifolia Plantation to the Distance From the Coastline
YUAN Feng, WANG Yan-yan, LIU He-na, LI Mao-jin, WU Cheng-zhen, CHEN Can
2020, 36(9):  1154-1160.  doi:10.19741/j.issn.1673-4831.2019.0897
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Assessing the dynamics of nutrient cycling across environmental gradients in an ecosystem accurately plays a key role in evaluating ecosystem function. This study aims to investigate the effects of environmental gradient produced by the distance from the coastline on litter quantity and quality in a Casuarina equisetifolia plantation in Chihu State-owned Protected Forest Farm in Hui'an, China. The results show that: (1) The annual litter production of Casuarina equisetifolia was (9.939±0.708) t·hm-2, and due to the influence of wind and stand density, the litter production of Casuarina equisetifolia conformed to a unimodal pattern rising first and then declining with the increasing distance from the coastline. (2) Nutrient contents of Casuarina equisetifolia litter were significantly affected by the distance of the trees from the coastline. The nutrient content and variation range of litter under different gradients were Ca>K> Mg>P. The contents of P, K and Mg decreased gradually, while the content of Ca increased first and then decreased with the increasing of distance from the coastline. There was a significant correlation between nutrient content (except Ca, P<0.01) and the distance from the coastline, which might be attributed to leaf nutrient reabsorption and spatial distribution of soil nutrients. (3) The distance from the coastline had little effects on the nutrients content of litter over time, and the nutrients content was significantly affected by monthly climate change. The temporal patterns of P, K and Mg content were similar across different gradients, increasing or decreasing in the same month and with higher contents in the autumn and winter than in the spring and summer. (4) The interaction between elements could affect the nutrient content of litter. The correlations between Ca and other elements were not significant (P>0.05). Litter P content was significantly positive correlated with K and Mg content (P<0.01), while there was a significant negative correlation between K and Mg (P<0.01). The findings provided a theoretical basis for the sustainable management and protection of Casuarina equisetifolia plantations in coastal area.
Effects of Long-term Organic Fertilization on the Content of Soil Organic Phosphorus Fractions and Abundance of Soil Microorganism
WANG Jing, WANG Lei, ZHANG Ai-jun, ZHANG Hui, ZHANG Yong-chun
2020, 36(9):  1161-1168.  doi:10.19741/j.issn.1673-4831.2019.0544
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The effects of different fertilization regimes on soil organic phosphorus fractions (Po), the abundances of bacteria, fungi, and microorganisms associated with soil organic phosphorus transformation (phoD-harboring microbial), and alkaline phosphatase (ALP) were explored by analyzing soil samples collected from a long-term fertilization experimental site. A single-factor randomized block design was adopted and five treatments were set up as follows: (1) CK, no fertilizer treatment; (2) NK, N and K fertilizer treatment; (3) NPK, N, P and K fertilizer treatment; (4) M, organic fertilizer treatment; (5) NPKM, organic and inorganic fertilizers treatment. Results show that compared with the CK and NK, soil organic phosphorus contents were significantly increased by 52.3% and 47.8% for the M, and 34.7% and 30.6% for the NPKM, respectively. The available phosphorus contents in the M was 34.2 and 31.0 times of that in the CK and NK, respectively. The available phosphorus content in the NPKM was 25.3 times and 23.0 times of that in the CK and NK, respectively. Besides, the contents of labile organic phosphorus, moderately labile organic phosphorus, moderately resistant organic phosphorus and highly resistant organic phosphorus were significantly increased for the M and NPKM, compared with the CK. In comparison with the CK, NK and NPK, organic fertilizer application (M and NPKM) significantly stimulated the abundances of bacteria, fungi, and phoD-harboring microbes, and the activity of ALP (P<0.05). In addition, soil organic phosphorus fractions were significantly and positively correlated with the phoD-harboring microbes (P<0.05). There were significant (P<0.05) positive correlations between labile Po, moderately resistant Po, highly resistant Po and ALP. The effect of phoD-harboring microbes and ALP on the organic phosphorus fractions was in the order of highly resistant Po > labile Po > moderately resistant Po > moderately labile Po. Together, the application of organic fertilizer could increase the contents of soil organic phosphorus and different organic phosphorus fractions, the abundances of bacteria, fungi and phoD-harboring microbes and the activity of alkaline phosphatase.
Effect of Phosphorus Enriched Biochar Fertilizer Prepared From Pig-manure on the Soil-radish System
YANG Jing, ZHONG Hui, PAN Huan, TAN Yu-nan, YI Man, CHEN Yu-cheng
2020, 36(9):  1169-1176.  doi:10.19741/j.issn.1673-4831.2019.0465
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In order to promote the rational application of phosphorus(P)-enriched biochar fertilizer in purple soil of southwest China, pot experiments were conducted to investigate the effects of P-enriched biochar fertilizer prepared from pig manure on the physicochemical properties of purple soil, as well as its influence on the yield and quality of cherry radish. The results show that after adding P-enriched biochar fertilizer prepared from pig manure, the soil pH value and organic matter, total N and total K contents in soil were significantly increased. The opplication of P-enriched biochar fertilizer also increased the contents of available P by 21.72%-43.47% and 0.22%-28.42% during the rosette stage and fleshy root swelling stage of cherry radish, respectively. The above-ground and root biomass of cherry radish treated with this P-enriched biochar fertilizer were lifted by 17.20%-44.17% and 20.63%-83.31%, respectively. The contents of P, total sugar and vitamin C in cherry radish were significantly increased, and the content of P in cherry radish had a significant correlation with the content of available P in soil (P<0.01), while the Pb and Cd contents of cherry radish decreased respectively by 6.12%-44.49% and 4.19%-13.31%. In conclusion, application of P-enriched biochar fertilizer prepared from pig manure can significantly improve the physicochemical properties of purple soil, and increase the yield and quality of cherry radish.
Tempo-spatial Variations of Dissolved Organic Carbon and Heavy Metals in Miyun Section of Chaobai River
XU Xin-yao, PU Xiao, LIU Xun-liang, ZHANG Rui-ning, ZHANG Yu-hu, GAO Jing, DONG Xue, WANG Zi-kang
2020, 36(9):  1177-1184.  doi:10.19741/j.issn.1673-4831.2019.0953
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Elucidating dynamics of dissolved organic carbon (DOC) and heavy metals in drinking water sources provides critical implications for water source protection and drinking water treatments. In order to characterize tempo-spatial variations of DOC and heavy metals in Miyun section of Chaobai River which is a main drinking water source in Beijing, DOC and five heavy metals (Cu, Fe, Mn, Ni and Zn) as well as three water quality indicators [pH, total dissolved solids (TDS) and conductivity] in different seasons (spring, summer and autumn) and in different regions (R1: woodland region, R2: woodland and farmland mixed region, R3: urban region, and R4: farmland region) were investigated. The TDS and conductivity presented significant spatial heterogeneity among regions which were greatest in R4 (P<0.05), while seasonal variations of them in each region were subtle. The average DOC concentration was 30.60 mg·L-1, with remarkable fluctuations across regions (P<0.05) and slight changes across seasons. The lowest DOC concentrations were found in R1 in all seasons. The average concentrations of Cu, Fe, Mn, Ni and Zn were 1.07, 9.29, 3.30, 1.64 and 2.91 μg·L-1, respectively. Cu and Zn concentrations were greatest in spring, whilst Fe and Mn concentrations were greatest in summer and autumn. Significantly greater concentrations of five heavy metals were observed in R3 and R4 compared to the other regions. The spatial characteristics of DOC and heavy metal concentrations corresponded with the land use types adjacent to the stream. The water quality at stream sections in urban and agricultural regions was to a higher extent affected than in the regions with other land use types.
Effect of Ammonia Nitrogen, Copper and Antibiotics Sulfadimidine in Swine Wastewater on the Growth of Porphyridium cruentum
PENG Yao, HU Zheng-yu, XIAO Peng, XU Zhi-hui, CHANG Ting, CHENG Peng-fei
2020, 36(9):  1185-1191.  doi:10.19741/j.issn.1673-4831.2019.0829
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Swine wastewater treatment by microalgae is the biotechnology for the resource utilization of wastewater. The microalgae Porphyridium cruentum, which is rich in exopolysaccharide is selected as the object in this study. The effect of NH3-N, Cu2+, and antibiotic sulfadiazine from swine wastewater on the growth of Porphyridium cruentum was investigated. The study aims to investigate the effects of different conditions of pollutants on the growth of Porphyridium cruentum and determine the enrichment effects of the strain on NH3-N, Cu2+, and antibiotics sulfadiazine. The results show that the biomass of Porphyridium cruentum was 1.74, 0.85 and 0.68 g·L-1, respectively in the culture with NH3-N concentration of 50, 500 and 2 000 mg·L-1; with Cu2+ concentration of 0.5, 1.0 and 2.0 mg·L-1, the biomass of Porphyridium cruentum was 1.81, 1.83 and 1.58 g·L-1, respectively; and with antibiotic sulfadiazine concentration of 5, 10, 20, 100 and 200 mg·L-1, the biomass of Porphyridium cruentum was 1.18, 1.42, 1.30, 0.98 and 0.88 g·L-1, respectively. Moreover, the removal rates of NH3-N, Cu2+, and sulfamethazine by Porphyridium cruentum were 73.2%, 54.3% and 56.9%, respectively under the optimal concentrations of the mentioned pollutants. The results indicate that ammonia nitrogen could provide nutrition for the microalgae Porphyridium cruentum and promote growth of the microalgae. However, Cu2+ and high concentrations of antibiotic sulfadiazine could inhibit the growth of Porphyridium cruentum. The abundant exopolysaccharide from Porphyridium cruentum has provided a new idea for the bioconcentration and removal of refractory pollutant metal Cu2+ or antibiotics in swine wastewater.
Screening of Filter Material With Weak Ammonia Nitrogen Adsorption Capacity, and Filtration Pretreatment of Suspended Solids in Biogas Slurry for Nitrogen Reuse
LI Peng, WANG Peng-chao, MA Dong, ZHANG Cheng-jun, GUO Xuan, ZHAO Tong-ke, WANG Xuan
2020, 36(9):  1192-1199.  doi:10.19741/j.issn.1673-4831.2019.0911
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The key to improving the reutilization value of biogas slurry is to retain most of the slurry nitrogen content while removing the suspended solids (SS). For this study, static adsorption and desorption experiments were undertaken with quartz sand (QSD), a commonly used filtration medium, which was selected for its weak ammonia nitrogen adsorption capacity. A dynamic experiment was then carried out using two filter-filled columns with different QSD particle sizes to analyze the influence of QSD on SS and ammonia nitrogen in biogas slurry permeating through the column. Among the four low-cost filter materials tested (QSD, sea sand, zeolite, and alumina industry waste residue), QSD had the weakest ammonia nitrogen adsorption capacity in solution. The desorption rate of QSD was close to that of sea sand and far lower than that of zeolite and the alumina waste residue. In the QSD-filled columns an SS removal rate of up to 86.1% was achieved at a biogas slurry flow rate of 2.4 L·h-1. The SS removal rate was generally higher in the 0.5-1 mm particle size QSD-filled column (QSD column) than in the 3-5 mm QSD column. However, there was no significant difference in the rate of ammonia nitrogen removal from the biogas slurry between the two QSD particle sizes used. After 24 h of operation, a blockage started to appear at the inlet of both of the columns, and after 32 h the 3-5 mm QSD column was almost completely blocked. The 0.5-1 mm QSD column required a longer running time and less filter material (a lower filling height) than the 3-5 mm QSD column to remove the same amount of SS from the biogas slurry. The SS removal rate of the 0.5-1 mm QSD column was more than 80%, and it had no significant effect on the ammonia nitrogen in biogas slurry. The 0.5-1 mm particle size was suitable for use in a pretreatment unit for SS filtration of biogas slurry and would be beneficial for any subsequent nitrogen recovery process.
Accumulation of Cd and As in Rice (Oryza sativa) Under Different Water Management Coupled With Charcoal and Diammonium Phosphate Amendment
MI Ya-zhu, ZHU Guang-sen, ZHANG Xu, LIU Xiao-hong, SI You-bin
2020, 36(9):  1200-1209.  doi:10.19741/j.issn.1673-4831.2019.0960
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According to the field experiment next to a lead-zinc mining area in Anhui Province, the available cadmium (Cd) and arsenic (As) in farmland as well as rice yields were evaluated as affected by charcoal and diammonium phosphate (DAP) treatments under conventional irrigation (W1), whole growth period flooding (W2), and wet irrigation (W3). Moreover, the pH values, oxidation-reduction potential (Eh), and Cd and As accumulation in rice tissues were also investigated in this study. The results demonstrate that the application of charcoal and DAP enhanced the pH values in soils under all the three conditions of water management. With the rice growth, the pH value in farmland increased firstly and then decreased to neutral. The Eh values of soils showed a declining tendency with the increase of moisture. The Eh values under the different water management conditions followed the sequence of W1 > W3 > W2. Furthermore, the Eh values at W2 condition showed a weak reductive state. At the same water management condition, the available Cd content in soil and Cd content in root, stem leaves and grains decreased as the application amount of charcoal and DAP increased, respectively. In control group, the Cd contents in rice grains under W1, W2, and W3 treatments were (0.23±0.02), (0.19±0.03), and (0.22±0.04) mg·kg-1, respectively. After the charcoal and DAP application, Cd accumulation in rice grains was lower than 0.2 mg·kg-1 for all treatments. It was found that the reduction in Cd accumulation had an optimum efficiency in application of 0.44 kg·m-2 charcoal or 15.00 g·m-2 DAP under W2 treatment. On the other hand, the available As content increased after the charcoal and DAP application. The available As content in soil showed the lowest concentration range (0.88-1.22 mg·kg-1) in W2 treatments. In the W2 treatment group, it was observed that the available As content in soil and As accumulation were lower in rice roots, stem leaves and grains. Meanwhile, the inorganic As contents in rice grains were lower than 0.2 mg·kg-1. Overall, application of charcoal and DAP improved rice growth and increased rice yield. The rice yields were negatively correlated with the available Cd content in soil, but no significant correlation with the available As content was observed. Therefore, the application of 0.44 kg·m-2 charcoal or 15.00 g·m-2 DAP coupled with W2 water treatment could be adopted to promote rice yields in the condition of ensuring that As content in rice grains below 0.2 mg·kg-1, which simultaneously decreased the accumulation of Cd in rice grains.
Effects of Biochar on Remidiation of Peddy Soil Cu Pollution and Reducing Cu Accumulation in Rice
LI Hong-hong, ZHAO Ming-liu, DONG Hai-xia, TANG Shou-yin, WANG Guo
2020, 36(9):  1210-1217.  doi:10.19741/j.issn.1673-4831.2019.0635
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To explore the effect of biochar on the transfer of copper (Cu) in soil-rice system, a pot experiment was conducted with three rice cultivars, namely Teyou 009, Donglian 5, and Yiyou 673 planted in Cu-contaminated soils that had been amended with biochar applications (w=0, 2.5%, and 5% ). The results show that biochar applications increased soil pH and water-soluble soil organic carbon (WSOC) and decreased the soil available Cu significantly. Compared with the control, the CaCl2-extractable Cu content of 5% biochar application at tillering and maturity stage were reduced by 73.78%-78.96% and 87.61%-96.97%, respectively. At maturity stage under 5% biochar treatment the proportion of acid soluble Cu decreased by 38.34%-48.72%, while the proportion of oxidizable Cu increased by 34.24%-46.04% as compared to the control. With the increasing of biochar applications, the concentration of Cu in rice root, husk and brown rice was reduced significantly. Among the 3 rice varieties, the effect of biochar on inhibiting Cu uptake by root was strongest for Teyou 009. The result of spatial distribution of Cu in rice root show that biochar application apparently decreased the abundance of Cu across the root section, leading to lower Cu levels near the stele, which decreased the probability of Cu transfer to shoot. As a result, Cu content in brown rice of Teyou 009, Donglian 5, and Yiyou 673 under 5% biochar application was decreased by 33.99%, 28.39%, and 40.22%, respectively.
Citric Acid Elution Enhanced by Hydroxylamine Hydrochloride for the Remediation of Heavy Metal Contaminated Soil
DAI Zhu-qing, PENG Wen-wen, WANG Ming-xin, ZHANG Jin-yong, ZHANG Wen-yi
2020, 36(9):  1218-1225.  doi:10.19741/j.issn.1673-4831.2019.0780
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Hydroxylamine hydrochloride was used to improve the activity of heavy metals in soil, and its strengthening effect on washing efficiency of heavy metals in soil by citric acid was investigated. Based on the single factor experiment, the multi-factor experiment was designed with the response surface model method. The relationships between heavy metal washing efficiency and citric acid dosage, hydroxylamine hydrochloride dosage, liquid-solid ratio were fitted. The reaction conditions were optimized, and the heavy metal washing efficiency and environmental risk reduction rate were used to evaluate the treatment results. The results show that, compared with single treatment with 5 g·L-1 citric acid, addition of 10 g·L-1 hydroxylamine hydrochloride significantly improved the washing efficiency of heavy metals, of which the Pb washing efficiency increased by 36.2%. When both the dosage of citric acid and hydroxylamine hydrochloride were 8 g·L-1, the liquid-solid mass ratio was 12∶1, and the shaking time was 2 h, the washing efficiency of Cu, Zn, Pb, and Cd were 55.8%, 58.3%, 47.1% and 47.9%, respectively; and the environmental risk reduction rates were 87.8%, 85.9%, 38.2% and 90.7%, respectively. The removal rates of the weak acid extracted components of four heavy metals were between 37.6% and 86.2%, the removal rates of the reducible components were between 49.4% and 80.4%, and the contents of heavy metal in residues were significantly increased.
The Ideas on Survey Methods for Monitoring of Ammonia Emission Coefficient in Livestock and Poultry Breeding
WANG Wen-lin, LIU Bo, HE De-chun, HAN Yu-jie, DU Wei, TONG Yi, LI Wen-jing, SHI Chang-jie, DAI Shuo-yun, TIAN Yuan, LIU Ya-li, LUO Dan, LUO Kai-hong, WU Gen-yi
2020, 36(9):  1226-1232.  doi:10.19741/j.issn.1673-4831.2020.0315
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Ammonia from livestock and poultry farming is included in the second national census of pollution sources as an agricultural pollutant for the first time. However, due to the late start of ammonia emission control in livestock and poultry breeding, the ammonia emission coefficient has not been determined according to the characteristics of livestock production in China. Based on the principle of precise management and comprehensive summary for the work experience of the first time pollution census of livestock and poultry breeding pollution emission coefficient, it puts forward structure and type of livestock farming ammonia emission coefficient, as well as the layout and methods of field monitoring points. At the same time, on the basis of China's animal husbandry production and the key factors influencing the in-depth analysis of livestock and poultry ammonia emissions, it puts forward the idea for monitoring the ammonia emission coefficient distribution which meets the requirements of both geographical division and climatic division, and establishes the monitoring calibration method of livestock and poultry emission coefficient per unit standard for the first time. This method not only reflects the emission differences of different regions within each district, but improves the spatial resolution of the coefficient, eliminates the problem of large coefficient difference between adjacent districts and counties in different regions, simplifies the report design, improves the accuracy of ammonia emission accounting effectively, and can provide effective technical support for the monitoring of ammonia emission coefficient of livestock and poultry in the second national census of pollution sources.