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Yu R.,Nanjing University | Yu R.,The Key Laboratory of the Coastal Zone Exploitation and Protection | Wang J.,Anhui Agricultural University
Environmental Monitoring and Assessment | Year: 2015

Environmental sustainability has become the focus of agricultural sustainability. This study is aimed at evaluating the environmental sustainability of farmers’ land use decisions on saline-alkaline soil in China. Based on empirical and theoretical approaches, the decisions mainly include planting, crop distribution, irrigation, drainage, and fertilization. By surveying 22 administrative villages in typical ecologically fragile saline-alkaline areas of five regions (Shandong, Jiangsu, Jilin, Ningxia, and Xinjiang), the paper builds the evaluation criteria at village level, and obtains a comprehensive index. From the results, irrigation concerns are absent from decision-making. For other decisions, farmers in most villages can appropriately deal with planting, drainage, and fertilization according to the regional natural and social geography conditions. But the comprehensive index of crop distribution in the coastal areas is much stronger than in the northeast and northwest. It is found that the similarities of unsustainability lie in the planting of water-consuming crops, the arbitrary distribution of crops, lack of drainage planning, obsolete water conservancy facilities, excessive use of chemical fertilizers, etc. According to the research, on the one hand, it can guide farmers to rationally make use of saline-alkaline land; on the other hand, it can also provide the basis for government to make differentiated policies in different areas and enhance pertinence in the course of technological extension and application. © 2015, Springer International Publishing Switzerland.

Zhao W.,Nanjing University | Zhu X.,Nanjing University | Sun X.,Nanjing University | Sun X.,Guangxi University | And 3 more authors.
Environmental Science and Pollution Research | Year: 2015

Urban expansion is an important stressor to water bodies, and the spatial variations of their relations are increasingly highlighted by recent studies. What remain unclear, however, are the underlying drivers to the spatial variability. The paper was not limited to modeling spatially varying linkages but also drew attention to the local anthropogenic influential factors that shape land-water relations. We employed geographically weighted regression to examine the relationships between urban expansion (measured by land use change intensity) and water quality changes (focusing on six water quality indicators) in a recently fast-growing Chinese city, Lianyungang. Specifically, we analyzed how the local characteristics including urbanization level, environmental management, industrial zone expansion, and land use composition, attributed to the varying responses of water quality changes. Results showed that urbanization level significantly affects land-water linkages. Remarkable water quality improvement was accompanied by urbanization in highly developed watersheds, primarily due to strong influence from extensive water management practices (particularly for COD, BOD, NH3-N, and TP). By contrast, water qualities of less-urbanized watersheds were more sensitive and negatively responsive to land use changes. Clustering industrial activities acted as distinct contributor to Hg contamination, while boosted organic pollution control in highly urbanized areas. The approach proposed in the study can locate and further zoom into the hot-spots of human-water interactions, thereby contributing to better solutions for mitigating undesirable impacts of urbanization on water environment. © 2015 Springer-Verlag Berlin Heidelberg

Zhang R.,Kyoto University | Zhang R.,Nanjing University | Pu L.,Nanjing University | Pu L.,The Key Laboratory of the Coastal Zone Exploitation and Protection | And 3 more authors.
Environmental Monitoring and Assessment | Year: 2016

As coastal development becomes a national strategy in Eastern China, land use and landscape patterns have been affected by reclamation projects. In this study, taking Rudong County, China as a typical area, we analyzed land use change and its landscape ecological security responses in the tidal flat reclamation zone. The results show that land use change in the tidal flat reclamation zone is characterized by the replacement of natural tidal flat with agricultural and construction land, which has also led to a big change in landscape patterns. We built a landscape ecological security evaluation system, which consists of landscape interference degree and landscape fragile degree, and then calculated the landscape ecological security change in the tidal flat reclamation zone from 1990 to 2008 to depict the life cycle in tidal flat reclamation. Landscape ecological security exhibited a W-shaped periodicity, including the juvenile stage, growth stage, and maturation stage. Life-cycle analysis demonstrates that 37 years is required for the land use system to transform from a natural ecosystem to an artificial ecosystem in the tidal flat reclamation zone. © 2015, Springer International Publishing Switzerland.

Wang X.,Nanjing University | Pu L.,Nanjing University | Pu L.,The Key Laboratory of the Coastal Zone Exploitation and Protection | Zhang M.,Nanjing University | And 2 more authors.
Environmental Earth Sciences | Year: 2015

The spatial and temporal variation of soil organic carbon (SOC) and soil total nitrogen (STN) in a coastal reclamation area in eastern China were studied based on the ordinary kriging method. The 0–20 cm soil organic carbon pool (SOCP) and soil total nitrogen pool (STNP) ranged from 4.38 to 15.92 Mg/ha and from 0.24 to 2.37 Mg/ha, respectively, during the observed period. The results show there was a low level of spatial variation in both SOC and STN, which is to some extent the result of the same farmland management practiced in this region. The seasonal variation of SOC was attributed to plant growth and crop residue returning back to soil, while the spatial variation was mainly resulted from the fertilization practice. The average 0–20 cm SOCP and STNP were 10.38 ± 2.50 and 1.27 ± 0.38 Mg/ha, respectively, in the study region, both of which were much lower than in other ecosystems. Further analysis indicated that SOC was positively correlated with STN. This work revealed that the reclamation area from the tidal flat should be a potential sink for SOC and STN. © 2015, Springer-Verlag Berlin Heidelberg.

Xu Y.,Nanjing University | Pu L.,Nanjing University | Pu L.,The Key Laboratory of the Coastal Zone Exploitation and Protection | Zhang L.,Nanjing University of Finance and Economics
Sustainability (Switzerland) | Year: 2014

Human settlement expansion has very important effects on regional populationmigration, economic balance and ecosystem services. Understanding the evolution ofsettlement expansion and regional differences is significant for regional sustainability. Theresults showed that in the past 30 years, the urbanization rate in Jiangsu province waslower. From 1980 to 2010, the expansion area of urban settlement was larger than that ofrural settlement. Urban settlement expanded slowly from 1980 to 2005 and strongly from2005 to 2010. Rural settlement expanded greatly from 1980 to 1995, and 37.14% of settlement was mostly on cropland. The type of urban settlement expansion from 1980 to1995 and from 2000 to 2005 was compact expansion. Settlement expansion in the south ofJiangsu province was greater than that in the north of Jiangsu province. The spatial patternof settlement in most cities was a cluster. In the past 30 years, urban and rural settlementexpansion had significantly different impacts on the soil and water environment. Urbansettlement expansion was great in the south of Jiangsu province and widened the economicand social gap between the south and north of Jiangsu province. © 2014 by the authors.

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