Biological soil crusts （BSCs） play an important role in surface soil hydrology. Soils dominated with moss BSCs may have higher infiltration rates than those dominated with cyanobacteria or algal BSCs. However, it is...Biological soil crusts （BSCs） play an important role in surface soil hydrology. Soils dominated with moss BSCs may have higher infiltration rates than those dominated with cyanobacteria or algal BSCs. However, it is unnown whether improved infiltration in moss BSCs is accompanied by an increase in soil hydraulic conductivity or water retention capacity. We investigated this question in the Tengger Desert, where a 43-year-old revegetation program has promoted the formation of two distinct types of BSCs along topographic positions, i.e. the moss-dominated BSCs on the interdune land and windward slopes of the fixed sand dunes, and the al- gal-dominated BSCs on the crest and leeward slopes. Soil water retention capacity and hydraulic conductivity were measured using an indoor evaporation method and a field infiltration method. And the results were fitted to the van Genuchten-Mualem model. Unsaturated hydraulic conductivities under greater water pressure （〈-0.01 MPa） and water retention capacities in the entire pressure head range were higher for both crust types than for bare sand. However, saturated and unsaturated hydraulic conductivities in the near-saturation range （〉-0.01 MPa） showed decreasing trends from bare sand to moss crusts and to algal crusts. Our data suggested that topographic differentiation of BSCs significantly affected not only soil water retention and hydraulic conductivities, but also the overall hydrology of the fixed sand dunes at a landscape scale, as seen in the reduction and spatial variability in deep soil water storage.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
为探究土壤藻结皮对退化草地生态恢复的影响,在库布齐沙漠南缘退化草地,分别应用常规分析方法、样方调查法以及物种的多样性指数、丰富度指数和均匀度指数,研究人工土壤藻结皮发育过程中土壤肥力、植物群落结构和物种多样性的变化。结...为探究土壤藻结皮对退化草地生态恢复的影响,在库布齐沙漠南缘退化草地,分别应用常规分析方法、样方调查法以及物种的多样性指数、丰富度指数和均匀度指数,研究人工土壤藻结皮发育过程中土壤肥力、植物群落结构和物种多样性的变化。结果表明:经过3年的土壤藻改良,50 cm埋深的土壤中,土壤含水率增加了19.9%~123.9%,土壤中有机质含量增加了20.0%~30.4%,土壤中全氮和速效氮含量分别增加了31.6%~33.3%和22.8%~52.9%,土壤中全磷和速效磷含量分别增加了13.1%~20.3%和41.2%~53.7%;随着土壤藻结皮的发育,研究区退化草地增加了沙蓬、羊柴、沙柳和柠条4种草本植物,植物群落物种的多样性指数、丰富度指数和均匀度指数分别增加了67.0%、82.4%和57.9%,退化草地植物生产量由58.5 g DW/m2增加到241.6 g DW/m2,说明随着土壤藻结皮的发育,退化草地的土壤环境条件得到改善,植物群落结构和物种多样性明显增强,表明培植土壤藻结皮将有利于改善土壤环境,加速退化草地的生态恢复。展开更多
基金funded by the National Basic Research Program of China (2013CB429901)the National Natural Science Foundation of China (41471434, 31170385)the Foundation for Excellent Youth Scholars of CAREERI, Chinese Academy of Sciences
文摘Biological soil crusts （BSCs） play an important role in surface soil hydrology. Soils dominated with moss BSCs may have higher infiltration rates than those dominated with cyanobacteria or algal BSCs. However, it is unnown whether improved infiltration in moss BSCs is accompanied by an increase in soil hydraulic conductivity or water retention capacity. We investigated this question in the Tengger Desert, where a 43-year-old revegetation program has promoted the formation of two distinct types of BSCs along topographic positions, i.e. the moss-dominated BSCs on the interdune land and windward slopes of the fixed sand dunes, and the al- gal-dominated BSCs on the crest and leeward slopes. Soil water retention capacity and hydraulic conductivity were measured using an indoor evaporation method and a field infiltration method. And the results were fitted to the van Genuchten-Mualem model. Unsaturated hydraulic conductivities under greater water pressure （〈-0.01 MPa） and water retention capacities in the entire pressure head range were higher for both crust types than for bare sand. However, saturated and unsaturated hydraulic conductivities in the near-saturation range （〉-0.01 MPa） showed decreasing trends from bare sand to moss crusts and to algal crusts. Our data suggested that topographic differentiation of BSCs significantly affected not only soil water retention and hydraulic conductivities, but also the overall hydrology of the fixed sand dunes at a landscape scale, as seen in the reduction and spatial variability in deep soil water storage.
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.
文摘为探究土壤藻结皮对退化草地生态恢复的影响,在库布齐沙漠南缘退化草地,分别应用常规分析方法、样方调查法以及物种的多样性指数、丰富度指数和均匀度指数,研究人工土壤藻结皮发育过程中土壤肥力、植物群落结构和物种多样性的变化。结果表明:经过3年的土壤藻改良,50 cm埋深的土壤中,土壤含水率增加了19.9%~123.9%,土壤中有机质含量增加了20.0%~30.4%,土壤中全氮和速效氮含量分别增加了31.6%~33.3%和22.8%~52.9%,土壤中全磷和速效磷含量分别增加了13.1%~20.3%和41.2%~53.7%;随着土壤藻结皮的发育,研究区退化草地增加了沙蓬、羊柴、沙柳和柠条4种草本植物,植物群落物种的多样性指数、丰富度指数和均匀度指数分别增加了67.0%、82.4%和57.9%,退化草地植物生产量由58.5 g DW/m2增加到241.6 g DW/m2,说明随着土壤藻结皮的发育,退化草地的土壤环境条件得到改善,植物群落结构和物种多样性明显增强,表明培植土壤藻结皮将有利于改善土壤环境,加速退化草地的生态恢复。
