ALBERT

Description: The Songnen Plain of the Northeast China is one of the three largest soda saline-alkali regions worldwide. To better understand soil alkalinization and salinization in this important agricultural region, it is vital to explore the distribution and variation of soil alkalinity and salinity in space and time. This study examined soil properties and identified the variables to extract soil alkalinity and salinity via physico-chemical, statistical, spectral, and image analysis. The physico-chemical and statistical results suggested that alkaline soils, coming from the main solute Na2CO3 and NaHCO3 in parent rocks, characterized the study area. The pH and electric conductivity (EC ) were correlated with both narrow band and broad band reflectance. For soil pH, the sensitive bands were in short wavelength (VIS) and the band with the highest correlation was 475 nm (r = 0.84). For soil EC, the sensitive bands were also in VIS and the band with the highest correlation was 354 nm (r = 0.84). With the stepwise regression, it was found that the pH was sensitive to reflectance of OLI band 2 and band 6, while the EC was only sensitive to band 1. The R2Adj (0.73 and 0.72) and root mean square error (RMSE) (0.98 and 1.07 dS/m) indicated that, the two stepwise regression models could estimate soil alkalinity and salinity with a considerable accuracy. Spatial distributions of soil alkalinity and salinity were mapped from the OLI image with the RMSE of 1.01 and 0.64 dS/m, respectively. Soil alkalinity was related to salinity but most soils in the study area were non-saline soils. The area of alkaline soils was 44.46% of the basin. Highly alkaline soils were close to the Zhalong wetland and downstream of rivers, which could become a severe concern for crop productivity in this area.

Description: This paper employs the quadratic directional output distance function to derive shadow prices of China’s aggregate carbon emissions at the province level between 1997 and 2010. The empirical results indicate that the national weighted average shadow price presents an “N-shape” curve across the sample period, experiencing the initial phase of growth followed by a phase of deterioration, and then a further increase. This change trend implies that the cost of carbon emissions reduction is increasing. In addition, the shadow price varies significantly across provinces, which means that China should uphold the principal of “common but differentiated responsibilities” in regional carbon emissions reduction. Generally, the shadow price of the east provinces with high economic development is markedly higher than that of the west provinces with low economic development. The OLS regression results indicate that the shadow price positively connected with the regional economic development levels. Moreover, an inflection point exists in the relation curve between the shadow price and GDP per capita, that is, the increase rate of the shadow price becomes small when the GDP per capita is less than 18.1 thousand Yuan, while it becomes large when the GDP per capita surpasses 18.1 thousand Yuan. With the economic growth, the cost of carbon emissions reduction would be significantly increased. The empirical results can provide more insight for policymakers.