Assessment on the Vulnerability of Agricultural Eco-environment of Hilly Basin Area in the Middle of Hunan Province——A Case Study of Hengyang Basin

[Objective] The study aimed to assess the vulnerability of agricultural eco-environment of hilly basin area in the middle of Hunan Prov- ince. [ Method] Taking Hengyang basin as an example, we firstly chose 13 indicators from natural, social and economic subsystem to assess the vulnerability of agricultural eco-environment in hilly basin area in the middle of Hunan Province. Afterwards, by using principal component analysis, we calculated the weight of each indicator and the vulnerability of agricultural eco-environment of seven regions, finally analyzed the spatial distribu- tion of agricultural eco-envimnment vulnerability. [ Result] The weight of farmers＇ net income per capita was up to 0.140, followed by forest coverage （0.137）. Among the seven counties, the vulnerability of agricultural eco-environment was primarily moderate, while Hengnan County had the highest vulnerability, followed by Hengyang County, and their vulnerability was extremely serious. In addition, Leiyang City was the minimum fragile region, namely slightly fragile region. In general, the vulnerability of peripheral counties was lower than that of central counties. [ Conclusion] The research could provide scientific references for the restoration and reconstruction of agro-ecological environment as well as the establishment of agri- cultural Dreduction decisions.

Theories and Practices of Remembering Nostalgia in New Urbanization

As the National Conference on New Urbanization proposed, "(new urbanization) should enable residents to see mountains and waters, and remember nostalgia". Nostalgia is a kind of memories and yearning deep in the heart for one's homeland or the place once lived in, it is the softest emotion and also a spiritual need. To keep nostalgia in new urbanization is to preserve history, culture, memories, and humanistic spirits of the homeland, and also to maintain local cultural genes and carry forward rural civilization. The foundation of remembering the nostalgia is to intensify culture protection. And by means of protecting cultural heritage and style of the traditional settlement practically, preserving cultural gene, inheriting cultural memory, creating cultural brand and characteristic landscape etc., the nostalgia can meet the spiritual demands of the residents, such as homesickness, life emotion, historical emotion and cultural emotion in the process of new urbanization. The key of remembering nostalgia is to promote the construction of small characteristic towns. Relying on on-site urbanization, the signifi cant ways of achieving new urbanization are star-studded layout of small towns and the construction of small characteristic tourism town. The construction of Hunan-style Tourism Town is a positive attempt and exploration of remembering nostalgia, and it contributes to the construction of a beautiful and poetic homeland for the human-centered new urbanization.

Phosphorus utilization and microbial community in response to lead/iron addition to a waterlogged soil

Constructed wetlands have emerged as a viable option for helping to solve a wide range of water quality problems. However, heavy metals adsorbed by substrates would decrease the growth of plants, impair the functions of wetlands and eventually result in a failure of contaminant removal. Typha latifolia L., tolerant to heavy metals, has been widely used for phytoremediation of Pb/Zn mine tailings under waterlogged conditions. This study examined effects of iron as ferrous sulfate （100 and 500 mg/kg） and lead as lead nitrate （0, 100, 500 and 1000 mg/kg） on phosphorus utilization and microbial community structure in a constructed wetland. Wetland plants （T. latifolia） were grown for 8 weeks in rhizobags filled with a paddy soil under waterlogged conditions. The results showed that both the amount of iron plaque on the roots and phosphorus adsorbed on the plaque decreased with the amount of lead addition. When the ratio of added iron to lead was 1：1, phosphorus utilized by plants was the maximum. Total amount of phospholipids fatty acids （PLFAs） was 23%-59% higher in the rhizosphere soil than in bulk soil. The relative abundance of Gram-negative bacteria, aerobic bacteria, and methane oxidizing bacteria was also higher in the rhizosphere soil than in bulk soil, but opposite was observed for other bacteria and fungi. Based on cluster analysis, microbial communities were mostly controlled by the addition of ferrous sulfate and lead nitrate in rhizosphere and bulk soil, respectively.

Mapping wetland changes in China between 1978 and 2008

Four wetland maps for all China have been produced,based on Landsat and CBERS-02B remote sensing data between 1978 and 2008 (1978,1990,2000 and 2008).These maps were mainly developed by manual interpretation and validated by substantial field investigation in 2009.Based on these maps,we analyzed the 2008 wetland distribution in China and discussed wetland changes and their drivers over the past 30 years.(i) There were about 324097 km 2 of wetlands in 2008,for which inland marshes or swamps were the most common wetland type (35%),with lakes (26%) second.Most of the wetlands were in Heilongjiang,Inner Mongolia,Qinghai and Tibet,occupying about 55% of the national wetland area.(ii) From 1978 to 2008,China's wetland area continually and significantly decreased,by about 33% based on changes in the wetland map.This was in sharp contrast to the increase in artificial wetlands,which increased by about 122%.Inland marshes accounted for the main loss of total wetlands from 1978 to 2000.From 2000 through 2008,riverine and lacustrine wetlands constituted the main wetland loss.Fortunately however,the rate of wetland loss decreased from 5523 to 831 km 2 /a.(iii) The change ratio of lost natural wetlands (including inland and coastal wetlands) to non-wetlands has decreased slightly over the past 30 years.From 1978 to 1990,nearly all natural wetlands (98%) lost were transformed into non-wetlands.However,the ratio declined to 86% from 1990 to 2000,and to 77% from 2000 to 2008.(iv) All Chinese provinces were divided into three groups according to patterns of wetland changes,which could relate to the driving forces of such changes.Tibet was completely different from other provinces,as it was one representative example in which there was a net wetland increase,because of global warming and decreased human activity since 1990.Increased economic development caused considerable wetland loss in most eastern provinces,and artificial wetlands increased.