scholarly journals Responses of remnant wetlands in the Sanjiang Plain to farming-landscape patterns

2022 ◽  
Vol 135 ◽  
pp. 108542
Author(s):  
Chunyu Luo ◽  
Xiaoling Fu ◽  
Xingyu Zeng ◽  
Hongjie Cao ◽  
Jifeng Wang ◽  
...  
Keyword(s):  
Sanjiang Plain ◽  
Landscape Patterns ◽  
The Sanjiang Plain

scholarly journals Levels, Inventory, and Risk Assessment of Heavy Metals in Wetland Ecosystem, Northeast China: Implications for Snow Cover Monitoring

Water ◽  
2021 ◽  
Vol 13 (16) ◽  
pp. 2161
Author(s):  
Fuxiang Zhang ◽  
Bo Meng ◽  
Shang Gao ◽  
Rupert Hough ◽  
Peng Hu ◽  
...  
Keyword(s):  
Heavy Metals ◽  
Snow Cover ◽  
Environmental Quality ◽  
Regional Scale ◽  
Class Ii ◽  
Sanjiang Plain ◽  
Preliminary Evaluation ◽  
Monitoring Method ◽  
The Sanjiang Plain ◽  
Water Pollution Index

Snow cover is a unique environmental medium in cold regions that can cause potential risks to the ecological environment, due to the release of pollutants that are stored in it. In this study, the Qixing River wetland, located in the Sanjiang Plain of China, was taken as the target research area. Heavy metals in snow cover, including Cu, Ni, Cr, Cd, Pb, and Zn were measured at 19 sampling sites. The results showed that the average concentrations of heavy metals were: Zn (103.46 ± 39.16) > Pb (13.08 ± 4.99) > Cr (11.97 ± 2.82) > Ni (9.55 ± 4.96) > Cu (6.19 ± 1.79) > Cd (0.55 ± 0.25) μg·L−1. Cr and Zn were between Class I and Class II in the “Environmental Quality Standards for Surface Water” of China (GB3838-2002). Pb in snow exceeded the upper limit of Class II, and was significantly higher than concentrations measured in water samples from the Qixing River wetland (p < 0.05), indicating that atmospheric deposition during winter was the major source of Pb. The water pollution index (WPI) indicated that 61.0% of samples could be considered of “clean” status, while the contribution of Zn, Pb, and Cr to WPI were 33.3%, 21.0%, and 19.3%, respectively. A preliminary evaluation of heavy metal inventory in snow cover showed that the residue level of Zn was the highest (2313.57 ± 1194.67 μg·m−2), while Cd was the lowest (13.91 ± 10.45 μg·m−2). The areas with high residues of heavy metals were all located near the buffer zone of the wetland (except for Zn), where snow depth tended to be greatest. Exposure analysis indicated that the risks to winter resident birds from snow ingestion was minimal, but it should be noted that the exposure risk was higher in birds with lower bodyweights. This study provides important information and scientific knowledge on the pollution characteristics and residue inventory of heavy metals in wetland ecosystems, while the results can also provide a monitoring method, reflecting atmospheric environmental quality at a local or regional scale.

scholarly journals Simulating Land-Use Changes and Predicting Maize Potential Yields in Northeast China for 2050

2021 ◽  
Vol 18 (3) ◽  
pp. 938
Author(s):  
Luoman Pu ◽  
Jiuchun Yang ◽  
Lingxue Yu ◽  
Changsheng Xiong ◽  
Fengqin Yan ◽  
...  
Keyword(s):  
Land Use ◽  
Food Security ◽  
Northeast China ◽  
Land Use Changes ◽  
Sanjiang Plain ◽  
Potential Production ◽  
Potential Yield ◽  
The Sanjiang Plain ◽  
Ecological Zones ◽  
The Future

Crop potential yields in cropland are the essential reflection of the utilization of cropland resources. The changes of the quantity, quality, and spatial distribution of cropland will directly affect the crop potential yields, so it is very crucial to simulate future cropland distribution and predict crop potential yields to ensure the future food security. In the present study, the Cellular Automata (CA)-Markov model was employed to simulate land-use changes in Northeast China during 2015–2050. Then, the Global Agro-ecological Zones (GAEZ) model was used to predict maize potential yields in Northeast China in 2050, and the spatio-temporal changes of maize potential yields during 2015–2050 were explored. The results were the following. (1) The woodland and grassland decreased by 5.13 million ha and 1.74 million ha respectively in Northeast China from 2015 to 2050, which were mainly converted into unused land. Most of the dryland was converted to paddy field and built-up land. (2) In 2050, the total maize potential production and average potential yield in Northeast China were 218.09 million tonnes and 6880.59 kg/ha. Thirteen prefecture-level cities had maize potential production of more than 7 million tonnes, and 11 cities had maize potential yields of more than 8000 kg/ha. (3) During 2015–2050, the total maize potential production and average yield decreased by around 23 million tonnes and 700 kg/ha in Northeast China, respectively. (4) The maize potential production increased in 15 cities located in the plain areas over the 35 years. The potential yields increased in only nine cities, which were mainly located in the Sanjiang Plain and the southeastern regions. The results highlight the importance of coping with the future land-use changes actively, maintaining the balance of farmland occupation and compensation, improving the cropland quality, and ensuring food security in Northeast China.

Microbial CO2 production from surface and subsurface soil as affected by temperature, moisture, and nitrogen fertilisation

Soil Research ◽  
2008 ◽  
Vol 46 (3) ◽  
pp. 273 ◽  
Author(s):  
Xiaobin Jin ◽  
Shenmin Wang ◽  
Yinkang Zhou
Keyword(s):  
Soil Temperature ◽  
Water Content ◽  
Soil Water ◽  
Soil Water Content ◽  
Sanjiang Plain ◽  
Co2 Production ◽  
The Sanjiang Plain ◽  
Subsurface Soil ◽  
C Mineralisation ◽  
Q10 Values

The Sanjiang Plain of north-east China is presently the second largest freshwater marsh in China. The drainage and use of marshes for agricultural fields occurred in the past 50 years, resulting in the increase in cultivated land from about 2.9 × 108 m2 in 1893 to 4.57 × 1010 m2 in 1994. Under human disturbance in the past half century, the environment in Sanjiang Plain has had significant change. We hypothesised that environmental factors such as soil moisture, soil temperature, and soil N levels affect the rates of soil organic C mineralisation and the nature of the controls on microbial CO2 production to change with depth through the soil profile in the freshwater marsh in the Sanjiang Plain. In a series of experiments, we measured the influence of soil temperature, soil water content, and nitrogen additions on soil microbial CO2 production rates. The results showed that Q10 values (the factor by which the CO2 production rate increases when the temperature is increased by 10°C) significantly increased with soil depth through the soil profile (P < 0.05). The average Q10 values for the surface soils were 2.7 (0–0.2 m), significantly lower than that (average Q10 values 3.3) for the subsurface samples (0.2–0.6 m) (P < 0.05), indicating that C mineralisation rates were more sensitive to temperature in subsurface soil horizons than in surface horizons. The maximum respiration rate was measured at 60% water hold capacity for each sample. The quadratic equation function adequately describes the relationship between soil respiration and soil water content, and the R2 values were > 0.80. The sensitivity of microbial CO2 production rate response to soil water content for surface soils (0–0.2 m) was slightly lower than for subsurface soils (0.2–0.6 m). The responses of actual soil respiration rates to nitrogen fertilisation were different for surface and subsurface soils. In the surface soils (0–0.2 m), the addition of N caused a slight decreased in respiration rates compared with the control, whereas, in the subsurface soils (0.2–0.6 m), the addition of N tended to increase microbial CO2 production rates, and the addition of 10 µg N/g soil treatment caused twice the increase in C mineralisation rates of the control. Our results suggested that the responses of microbial CO2 production to changes in soil moisture, soil temperature, and soil N levels varied with soil depth through the profile, and subsurface soil organic C was more sensitive to temperature increase and nitrogen inputs in the freshwater marsh of the Sanjiang Plain.

Ecosystem-atmosphere exchange of CO2 in a temperate herbaceous peatland in the Sanjiang Plain of northeast China

2015 ◽  
Vol 75 ◽  
pp. 16-23 ◽  
Author(s):  
Xiaoyan Zhu ◽  
Changchun Song ◽  
Christopher Martin Swarzenski ◽  
Yuedong Guo ◽  
Xinhou Zhang ◽  
...  
Keyword(s):  
Northeast China ◽  
Sanjiang Plain ◽  
The Sanjiang Plain

scholarly journals DOC concentrations and spectroscopic characteristics in surface runoff from contrasting wetland ecosystems: a case study in the Sanjiang Plain, Northeast China

2012 ◽  
Vol 9 (6) ◽  
pp. 7919-7945
Author(s):  
L. L. Wang ◽  
C. C. Song ◽  
G. S. Yang
Keyword(s):  
Land Use ◽  
Surface Runoff ◽  
Rice Paddy ◽  
Sanjiang Plain ◽  
Natural Wetland ◽  
Artificial Wetland ◽  
The Sanjiang Plain ◽  
Wetland Ecosystems ◽  
Wetland Site ◽  
Spectroscopic Characteristics

Abstract. Dissolved organic carbon (DOC) is a significant component of carbon and nutrient cycling in fluvial ecosystems. Natural wetlands, as important DOC sources for river and ocean ecosystems, have experienced extensive natural and anthropogenic disturbances such as climate change, hydrological variations and land use change in recent years. In this study, we examined the concentrations and spectroscopic characteristics of DOC in surface runoff from contrasting wetlands along the lower Amur River Basin in the Sanjiang Plain, Northeastern China. Surface runoff from seven sites (two natural phialiform wetlands, three natural riparian wetland, one degraded wetland, and one artificial wetland i.e. rice paddy) were monitored during the growing seasons of 2009 and 2010. Surface runoff from the natural wetland sites exhibited a wide range of DOC concentrations (10.06–48.73 mg l−1) during the two-year sampling period. The specific ultraviolet absorbance (SUVA) and color values of DOC in surface runoff were also highly variable at different natural wetland sites. Our analysis also found that DOC values were significantly lower in the surface runoff at the artificial wetland site compared with those from surface runoff at the five natural wetland sites and one degraded wetland site (P < 0.01). The colour per carbon unit (C / C) ratio in surface runoff at the artificial wetland site was one to three times lower, while the E4 / E6 ratio (Abs465 / Abs665) was reduced by 42.07% to 55.36%, compared to those from runoff water at the five natural wetland sites. The C / C ratios in surface runoff at the natural wetland sites were higher than that from surface runoff at the degraded wetland, which in turn has greater values than that from surface runoff at the artificial wetland site. Meanwhile, the E4 / E6 ratio in the surface runoff from the artificial wetland was lower compared to that in surface runoff at the degraded wetland site (P < 0.05). This implies that disturbance to DOC concentrations and spectroscopic characteristics in surface runoff is stronger from natural wetland conversion to rice paddy land than that from wetland degradation. The dataset from this study can provide insightful points for understanding the underlying mechanisms of aquatic DOC dynamics from wetland ecosystems, and improve land use policy and management strategies in the future.

scholarly journals Crop Mapping in the Sanjiang Plain Using an Improved Object-Oriented Method Based on Google Earth Engine and Combined Growth Period Attributes

2022 ◽  
Vol 14 (2) ◽  
pp. 273
Author(s):  
Mengyao Li ◽  
Rui Zhang ◽  
Hongxia Luo ◽  
Songwei Gu ◽  
Zili Qin
Keyword(s):  
Large Scale ◽  
Vegetation Index ◽  
Object Oriented ◽  
Growth Period ◽  
Sanjiang Plain ◽  
Google Earth ◽  
Utilization Rate ◽  
Growth Stages ◽  
The Sanjiang Plain ◽  
Growth Method

In recent years, the scale of rural land transfer has gradually expanded, and the phenomenon of non-grain-oriented cultivated land has emerged. Obtaining crop planting information is of the utmost importance to guaranteeing national food security; however, the acquisition of the spatial distribution of crops in large-scale areas often has the disadvantages of excessive calculation and low accuracy. Therefore, the IO-Growth method, which takes the growth stage every 10 days as the index and combines the spectral features of crops to refine the effective interval of conventional wavebands for object-oriented classification, was proposed. The results were as follows: (1) the IO-Growth method obtained classification results with an overall accuracy and F1 score of 0.92, and both values increased by 6.98% compared to the method applied without growth stages; (2) the IO-Growth method reduced 288 features to only 5 features, namely Sentinel-2: Red Edge1, normalized difference vegetation index, Red, short-wave infrared2, and Aerosols, on the 261st to 270th days, which greatly improved the utilization rate of the wavebands; (3) the rise of geographic data processing platforms makes it simple to complete computations with massive data in a short time. The results showed that the IO-Growth method is suitable for large-scale vegetation mapping.

scholarly journals Effects of Carbon Addition on Dissimilatory Fe(III) Reduction in Freshwater Marsh and Meadow Wetlands

2018 ◽  
Vol 10 (11) ◽  
pp. 4309 ◽  
Author(s):  
Xiaoyan Zhu ◽  
Yuxiang Yuan ◽  
Ming Jiang
Keyword(s):  
Iron Reduction ◽  
Reduction Rate ◽  
Negative Relationship ◽  
Sanjiang Plain ◽  
Freshwater Marsh ◽  
Freshwater Wetlands ◽  
Natural Environments ◽  
Carbon Addition ◽  
Soil Slurry ◽  
The Sanjiang Plain

The progress of dissimilatory iron(III) reduction is widespread in natural environments, particularly in anoxic habitats; in fact, wetland ecosystems are considered as “hotspots” of dissimilatory Fe(III) reduction. In this study, we conducted soil slurry and microbial inoculation anaerobic incubation with glucose, pyruvate, and soluble quinone anthraquinone-2,6-disulphonate (AQDS) additions in freshwater marsh and meadow wetlands in the Sanjiang Plain, to evaluate the role of carbon addition in the rates and dynamics of iron reduction. Dissimilatory Fe(III) reduction in marsh wetlands responded more quickly and showed twice the potential for Fe(III) reduction as that in meadow wetland. Fe(III) reduction rate in marsh and meadow wetlands was 76% and 30%, respectively. Glucose had a higher capacity to enhance Fe(III) reduction than pyruvate, which provides valuable information for the further isolation of Fe reduction bacteria in pure culture. AQDS could dramatically increase potential Fe(III) reduction as an electron shuttle in both wetlands. pH exhibited a negative relationship with Fe(III) reduction. In view of the significance of freshwater wetlands in the global carbon and iron cycle, further profound research is now essential and should explore the enzymatic mechanisms underlying iron reduction in freshwater wetlands.

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