关键词: 聚丙烯酰胺（PAM）, 生物炭, 土壤水力性质, 海涂围垦区, 盐碱土

Abstract: By methods of remote sensing, GIS and mathematical statistics, together with urbanization intensity index, the spatialtemporal evolution characteristics of urbanization expansion of a coastal city, Yantai from 1974 to 2009 were studied. Meanwhile, based on landscape pattern metrics and ecological risk index, we studied the landscape pattern dynamic changes and spatial characteristics of landscape ecological risk during 1990-2009 under condition of urban expansion. The results showed that the area of urban land increased by 189.77 km² during 1974-2009 and the average annual expansion area was 5.42 km². The urbanization intensity index during 2004-2009 was 3.92 times of that during 1974-1990. The most significant changes of land uses were urban land and farmland. The changes of landscape pattern metrics for land use patterns indicated that the intensity of human activities was increasing gradually in this period. The landscape ecological risk pattern of Yantai City appeared as a circle distribution along the coastline. The farther the distance to the coastline, the smaller the ecological risk index was. The ratio of high ecological risk and subhigh ecological risk zones of the study case in 2009 was 2.23 times of that in 1990. A significant linear relationship of urbanization intensity index and regional ecological risk was observed in the study.

Key words: coastal reclamation region, soil hydraulic pro-perties., polyacrylamide, saline soil, biochar