Salt marshes in estuarine and coastal zone play a key role on erosion control and coastal protection for their attenuating wave height and dissipating wave energy. In this study, we selected three typical salt marsh species: Spartina alterniflora, Phragmites australis, Spirpus×mariqueter in Changjiang estuary to measure the capability of attenuating and dissipating wave with selflogging wave sensors and Trimble GPS. Six sampling lines offshore and three sites on each transect with the pattern of “mudflatsalt marsh frontiersalt marsh” have been set up. Wave attenuation onshore in terms of significant wave height and wave energy have been analysed through 19 tidal periods with three salt marshes distribution patterns. The results show that: 1) The capability of coastal protection in typical salt marshes ranks with an order Spartina alterniflora＞Phragmites australis＞Spirpus×mariqueter. They attenuated 80% of wave heights (average) and dissipated 90% of total wave energy (average) as the wave crossed over the Spartina alterniflora 30m wide, or Phragmites australis 40m wide, or Spirpus×mariqueter 185m wide. 2) Vegetation density is the crucial factor for coastal protection which affected by plant characteristics, plant height, bed gradient, wave action and so on. There was obviously polynomial relation between Spirpus×mariqueter width and wave attenuation, exponential relation between Spartina alterniflora width and wave attenuation, logarithmic relation between Phragmites australis width and wave attenuation.

Key words：salt marsh; ecological function; coastal protection; wave attenuation; the Changjiang estuary

Soil permeability and water holding capacity are important soil hydraulic properties, which are also the basis of some hydrological functions, such as runoff regulation, and soil and water conservation. Four sampling locations in the head region of the Three Gorges Reservoir Area were selected to collect the soil samples, which contained the brown soil covered with subalpine temperate coniferous forest (BF), the yellow brown soil covered with deciduous coniferous broadleaved mixed shrubs (YBF), the yellow brown soil covered with tea tree (YBT), and the yellow soil covered with lowmountain warm coniferous forest (YF).Soil saturated hydraulic conductivities (Ks), soil water retention curves and physiochemical properties of these soil samples were analyzed in the lab, and the soil hydrological parameters of soil infiltration, water holding and water storage were quantified. Furthermore, the relationships between the hydrological parameters and soil physiochemical properties were analyzed. The results indicated that Ks ranged from 0.06 to 14.78 mm/min for all the soil samples. The highest Ks was observed from BF and YBF (i.e., 7.15～14.78 mm/min), followed by YF (1.39 mm/min), and YBT (1.17 mm/min).Significant differences of the saturated soil water content, capillary water content and field water capacity were observed among the four sampling locations, but little difference of wilting water content was identified. The soil properties of different horizons for the same soil profile was evaluated. With increasing soil depth, the saturated water content decreased, whereas the capillary water content and field capacity increased. Significant differences of the total water capacity were identified among the four sampling locations, and the total water capacity increased as the altitude increased. Correlation analysis between soil water parameters and soil properties indicated a significantly positive correlation between Ks and soil total porosity, and a significantly negative correlation between Ks and soil bulk density. There were significantly positive correlations between the saturated water content/capillary water content/field water capacity and total porosity/clay content, but significantly negative correlations with the soil bulk density. In addition, a significantly positive correlation was observed between the saturated water content and root density, whereas significantly negative correlations between capillary water content/field water capacity and the sand content were identified. Compared to YBT and YF, BF and YBF were characterized by higher infiltration rate and water holding capacity, behaving the better soil hydrological functions of runoff regulation and water conservation.

Key words：mountain soils; soil porosity; saturated hydraulic conductivity; water holding capacity; Three Gorges Reservoir Area

Panzhihua City is located in the confluence area of the Jinsha River and the Yalong River, which is an ecologically vulnerable region in the upper reache of the Yangtze River and a key area for implementing the “natural forest protection project” and the “returning cultivated land to forestry project” in China. Based on the MODISNDVI data from 2001 to 2010, meteorological data and other ancillary data in the same period, in this paper we analyzed the spatial and temporal variation of vegetation NDVI and its relationship with climatic factors and human activities by using the methods of maximum value composites, trend analysis and linear regression analysis. The results showed that the vegetation cover in the Panzhihua City was high and belonged to the high vegetation cover area. On the interannual scale, the vegetation cover showed an upward trend, with a growth rate of 0.02/10 a. During a year, NDVI was peaked in September and had the lowest value in March. The vegetation cover showed a horizontal spatial distribution pattern of “High in the north and Low in the south” and also showed significant differences in the vertical direction. The vegetation cover in the study area reached the maximum at the altitude range of 2 000 m-3 000 m and the slope range of 30 °-40 °, respectively. Constrained by hydrothermal conditions, the vegetation cover on shady slopes (0°-45°, 315°-360°) was higher than sunny slopes (135°-225°) , and the NDVI had the lowest value in the flat areas. For the entire study area, the areas with degraded vegetation and the vegetation greening areas accounted for 0.7% and 44.4% of the total area, respectively. The greening areas were much larger than that of the degraded area. Over the 10 years, the vegetation was more affected by temperature than precipitation. Besides, the largescale ecological engineering construction is the main driving factor for the increase of vegetation cover in the study area.

Key words：vegetation cover change; MODISNDVI; climate change; human activity; Panzhihua City

The study on the characteristics of microbial biomass carbon and the evolution rules in reclaimed soil can be beneficial for the evolution monitoring of the reclaimed soil quality and can also provide a scientific basis for improving the reclaimed soil quality. In this work, the method of “spatial sequence instead of time series” was employed to study the changes of the microbial biomass carbon (MBC) and the soil basic breathing (SBR) with reclamation years of Dongtan coal mine in Zoucheng City, and the relationships of MBC and SBR to the soil environmental factors were also analyzed. The results suggest that: firstly, the MBC and qSMBC increased with reclamation years. Secondly, the SBR values of reclaimed soil were significantly higher than those of the control group, and the metabolic quotient (qCO2) tended to decrease with reclamation years. Besides, the soil microbial biomass content recovered gradually after reclamation, and meanwhile, the carbon utilization efficiency of the soil microbial biomass increased gradually, which indicated that the soil environment became more suitable for the microbe growth. Thirdly, the soil MBC showed an obvious proportional relationship (p＜0.01) to available nitrogen (AN), total nitrogen (TN) and soil organic carbon (SOC), indicating that soil nutrient deficiency is the main limiting factor to soil microorganism growth after reclamation. On the other hand, the qCO2 was inversely proportional to AN, AP and MBC (p＜0.01), but was proportional to pH (p＜0.05), implying that the lack of nitrogen and phosphorus and a high soil pH environment had a negative effect on the growth of microbe. In sum, those results are of great theoretical and practical significance for the comprehensive evolution monitoring of soil quality and for the guidance of the reclamation work in the future.

Key words：coalmining subsidence area; soil microbial biomass carbon; soil microbial quotient; soil basal respiration

Based on the observation data of 47 meteorological stations in the North and South Qinling Mountains from 1960 to 2016, the spatiotemporal variations of agricultural climate resources such as light, heat and water in the north and south of Qinling were analyzed by methods of climate propensity index, MannKendall trend test, correlation analysis and inverse distance weighted interpolation. The results show that since 1960, the temperature and the active accumulated temperature of ≥10 ℃ in the northern and southern areas of Qinling have a significant increase trend. After 1995, the temperature has risen rapidly and reached a significant level in 2002. The temperature increased obviously in spring, winter and autumn, and the tendency of increasing temperature in the north of Qinling Mountain was more than the south of Qinling Mountain in space. From 1960 to 2016, precipitation in the north and south Qinling Mountains showed a slight downward trend overall. In terms of time, the precipitation was mainly reduced before 1995, after that, the precipitation gradually increased. In the perspective of space, from 1960 to 2016, the precipitation showed a relatively obvious decline in the regions including the north areas of Qinling mountains, along the Jialing River and the Danjiangkou reservoir area of the Hanjing River drainage area. Some areas show a slight upward trend, mainly in the Bawu Valley, the Daba mountain section of the Hanshui valley and the eastern part of the southern slope of the Qinling Mountains. In the recent 57 years, the relative humidity in the north and south Qinling Mountains showed a slight downward trend, and the degree of decline in recent years has increased. There is a significant decline for the sunshine duration. The sorting order to reduce of the sunshine hours of four seasons is summer,winter,autumn and spring. Significantly decreased areas are mainly distributed in the eastern plain of the study area, Hanzhong Basin, Guanzhong Basin and Bawu Valley.

Key words：agricultural climate resources; temporal and spatial changes; the northern and southern regions of Qinling Mountains

Based on the daily precipitation data at 115 meteorological stations in the Yangtze River Basin during 1963~2015, the spatial distributions and temporal change trends of some important extreme precipitation indices were analyzed. The results show that multiyear mean annual extreme precipitation and mean annual precipitation decrease from lower to upper reaches in the past 53 years, with the spatial distributions of their change trends as “increasedecreaseincrease” from lower and middle to the upper reaches. The proportions of annual extreme precipitation accounting for annual precipitation have significant difference although the contribution ratios show increasing trend in the whole basin in general. The spatial distribution and the change tread of precipitation amount of extreme rainfall events lasting one day are similar to those of annual extreme precipitation amount, with the ratios of them more than 65%, indicating that extreme rainfall events lasting one day are dominated in the Yangtze River Basin. The extreme rainfall events lasting two or more days, with the relative low contribution to annual extreme precipitation amount, appear mainly in regions of Anhui, Jiangsu and Jiangxi provinces, as well as central Sichuan. Annual maximum daily precipitation (MDP) increases from the lower to the upper reaches of the Yangtze River Basin. In the upper reach, MDP varies from 0 to 25 mm at Tuotuohe, Qumalai and Yushu stations, but from 25 to 50 mm at other stations; in the middle reach, MDP varies from 50 to 100 mm mostly, and from 100 to 150 mm secondly; in the low reach, the MDP from 100 to 150 mm is dominated.

Key words：extreme precipitation; precipitation contribution; different duration; Yangtze River Basin