As the important reserve land resources for food production,saline-alkali land should play a significant role to ensure the national food security in the context of global food crisis. The western Songnen Plain is one...As the important reserve land resources for food production,saline-alkali land should play a significant role to ensure the national food security in the context of global food crisis. The western Songnen Plain is one of main distribution regions of saline-alkali land in China,with great potential in agricultural development. In this study,the extent,transformation,spatial distribution and temporal change of saline-alkali land in the western Songnen Plain during 1954–2005 were investigated by using remote sensing and GIS spatial analysis methods. Saline-alkali land change was detected from a temporal series of topographic maps in 1954,satellite images of Landsat MSS in 1976,Landsat TM/ETM in 1988,2000 and 2005 through artificial visual interpretation. The results indicated a significant expansion in saline-alkali land area and aggravation in salinization. The area of saline-alkali land had increased from 401.48×103 ha in 1954 to 1 097.45×103 ha in 2005. While the ratio of light,moderate and serious salinized land areas changed from 6.72︰2.92︰1.00 to 1.25︰1.06︰1.00 in the study period. Grassland,cropland,swampland and water body were the major land use and land cover types from which saline-alkali land transformed. And the secondary salinization occured mainly in Da′an City,Tongyu County,Changling County,Daqing City,Dorbod Mongolian Autonomous County and Zhaoyuan County. Finally,seven large ecoregions and 14 corresponding sub-ecoregions were delineated out based on spatio-temopral dynamic characteristics of saline-alkali land and geo-relational environmental attributes. According to the results,measures of amelioration and ways of development of saline-alkali land in the western Songnen Plain were put forward.展开更多
The salt-resistant nitrogen-fixing cyanobacteria 888 was experimentally applied to the reclamation of saline and alkali soil in Songnen Plain in China. The pH, electrical conductivity (EC) and sodium adsorption ratio ...The salt-resistant nitrogen-fixing cyanobacteria 888 was experimentally applied to the reclamation of saline and alkali soil in Songnen Plain in China. The pH, electrical conductivity (EC) and sodium adsorption ratio (SAR) of different saline soils were studied and compared. Results show that different saline soils exhibit various physico-chemical properties. Saline-sodic soils in Songnen Plain are ameliorated by using nitrogen-fixing blue-green algae 888 in the experiment. It is indicated that cyanobacteria 888 can grow in saline and alkaline soils, and the conditions favorable for its growth are soil moisture of 50% and dry algae inoculation at 0.03 mg/cm2. The main actions of nitrogen-fixing cyanobacteria are keeping the adsorbability of rubber sheath for sodium, increasing the organic matter content of the soils and decreasing the pH and the degree of salinity in the soils. But the arid climate and soil depth are the main factors that limit the restoration of saline and alkaline soils.展开更多
基金Under the auspices of National Natural Science Foundation of China (No. 40771162)Key Item of Knowledge Innova-tion Programs of Chinese Academy of Sciences (No.KZCX2-SW-320-1)
文摘As the important reserve land resources for food production,saline-alkali land should play a significant role to ensure the national food security in the context of global food crisis. The western Songnen Plain is one of main distribution regions of saline-alkali land in China,with great potential in agricultural development. In this study,the extent,transformation,spatial distribution and temporal change of saline-alkali land in the western Songnen Plain during 1954–2005 were investigated by using remote sensing and GIS spatial analysis methods. Saline-alkali land change was detected from a temporal series of topographic maps in 1954,satellite images of Landsat MSS in 1976,Landsat TM/ETM in 1988,2000 and 2005 through artificial visual interpretation. The results indicated a significant expansion in saline-alkali land area and aggravation in salinization. The area of saline-alkali land had increased from 401.48×103 ha in 1954 to 1 097.45×103 ha in 2005. While the ratio of light,moderate and serious salinized land areas changed from 6.72︰2.92︰1.00 to 1.25︰1.06︰1.00 in the study period. Grassland,cropland,swampland and water body were the major land use and land cover types from which saline-alkali land transformed. And the secondary salinization occured mainly in Da′an City,Tongyu County,Changling County,Daqing City,Dorbod Mongolian Autonomous County and Zhaoyuan County. Finally,seven large ecoregions and 14 corresponding sub-ecoregions were delineated out based on spatio-temopral dynamic characteristics of saline-alkali land and geo-relational environmental attributes. According to the results,measures of amelioration and ways of development of saline-alkali land in the western Songnen Plain were put forward.
基金Sponsored by the Major State Scientific and Technological Projects of Water Pollution Control and Treatment(Grant No.2008ZX07208-005)
文摘The salt-resistant nitrogen-fixing cyanobacteria 888 was experimentally applied to the reclamation of saline and alkali soil in Songnen Plain in China. The pH, electrical conductivity (EC) and sodium adsorption ratio (SAR) of different saline soils were studied and compared. Results show that different saline soils exhibit various physico-chemical properties. Saline-sodic soils in Songnen Plain are ameliorated by using nitrogen-fixing blue-green algae 888 in the experiment. It is indicated that cyanobacteria 888 can grow in saline and alkaline soils, and the conditions favorable for its growth are soil moisture of 50% and dry algae inoculation at 0.03 mg/cm2. The main actions of nitrogen-fixing cyanobacteria are keeping the adsorbability of rubber sheath for sodium, increasing the organic matter content of the soils and decreasing the pH and the degree of salinity in the soils. But the arid climate and soil depth are the main factors that limit the restoration of saline and alkaline soils.
