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Effects of alfalfa coverage on runoff, erosion and hydraulic characteristics of overland flow on loess

Shufang WU, Pute WU, Hao FENG, G. P. Merkley

《环境科学与工程前沿(英文)》 2011年 第5卷 第1期   页码 76-83 doi: 10.1007/s11783-011-0282-x

摘要: An evaluation of the interactions between vegetation, overland and soil erosion can provide valuable insight for the conservation of soil and water. An experiment was conducted to study water infiltration, runoff generation process, rate of sediment erosion, and hydrodynamic characteristics of overland flow from a sloping hillside with different draw-off discharges from alfalfa and control plots with 20° slope. The effect of alfalfa on runoff and sediment transport reduction was quantitatively analyzed. Alfalfa was discussed for its ability to reduce the overland flow scouring force or change the runoff movement. Compared to the bare-soil plots, alfalfa plots generated a 1.77 times increase in infiltration rate. Furthermore, the down-slope water infiltration rate for the bare soil plots was higher than in the up-slope, while the opposite was found in the alfalfa plots. In addition, alfalfa had a significant effect on runoff and sediment yield. In comparison to the control, the runoff coefficient and sediment transportation rate decreased by 28.3% and 78.4% in the grass slope, respectively. The runoff generated from the alfalfa and bare-soil plots had similar trends with an initial increase and subsequent leveling to a steady-state rate. The transport of sediment reduced with time as a consequence of the depletion of loose surface materials. The maximum sediment concentration was recorded within the first few minutes of each event. The alfalfa plots had subcritical flow while the bare-soil plots had supercritical flow, which indicate that the capability of the alfalfa slope for resisting soil erosion and sediment movement was greater than for bare soil plots. Moreover, the flow resistance coefficient and roughness coefficient for the alfalfa plots were both higher than for the bare-soil plots, which indicate that overland flow in alfalfa plots had retarded and was blocked, and the flow energy along the runoff path had gradually dissipated. Finally, the ability to erode and transport sediment had decreased.

关键词: alfalfa     soil erosion     runoff and sedimentation     soil water infiltration     overland flow     hydrodynamic characteristics    

Microbial community and functional genes in the rhizosphere of alfalfa in crude oil-contaminated soil

Yi ZHONG, Jian WANG, Yizhi SONG, Yuting LIANG, Guanghe LI

《环境科学与工程前沿(英文)》 2012年 第6卷 第6期   页码 797-805 doi: 10.1007/s11783-012-0405-z

摘要: A rhizobox system constructed with crude oil-contaminated soil was vegetated with alfalfa ( L.) to evaluate the rhizosphere effects on the soil microbial population and functional structure, and to explore the potential mechanisms by which plants enhance the removal of crude oil in soil. During the 80-day experiment, 31.6% of oil was removed from the adjacent rhizosphere (AR); this value was 27% and 53% higher than the percentage of oil removed from the far rhizosphere (FR) and from the non-rhizosphere (NR), respectively. The populations of heterotrophic bacteria and hydrocarbon-degrading bacteria were higher in the AR and FR than in the NR. However, the removal rate of crude oil was positively correlated with the proportion of hydrocarbon-degrading bacteria in the rhizosphere. In total, 796, 731, and 379 functional genes were detected by microarray in the AR, FR, and NR, respectively. Higher proportions of functional genes related to carbon degradation and organic remediation, were found in rhizosphere soil compared with NR soil, suggesting that the rhizosphere selectively increased the abundance of these specific functional genes. The increase in water-holding capacity and decrease in pH as well as salinity of the soil all followed the order of AR>FR>NR. Canonical component analysis showed that salinity was the most important environmental factor influencing the microbial functional structure in the rhizosphere and that salinity was negatively correlated with the abundance of carbon and organic degradation genes.

关键词: crude oil-contaminated soil     phytoremediation     rhizosphere effects     rhizobox     functional genes    

Growth and abscisic acid responses of

Yue LI, Liqiang WAN, Yufei WANG, Xianglin LI

《农业科学与工程前沿(英文)》 2018年 第5卷 第1期   页码 80-86 doi: 10.15302/J-FASE-2017199

摘要: A pot experiment was conducted in a greenhouse with three alfalfa ( ) cultivars, Aohan, Zhongmu No.1 and Sanditi, to examine the morphological and physiological responses of alfalfa to water stress. The response of alfalfa to water stress at different growth stages was generally similar, but varied among cultivars. At the branching, flowering and podding stages, the shoot biomasses of Aohan and Zhongmu No.1 were greatly affected by, and responded quickly to, water stress. The shoot biomass of Sanditi was not affected by mild water stress, but had a slight response to moderate and severe water stress. The root/shoot ratios in Aohan and Zhongmu No.1 were more sensitive to water stress than in Sanditi, with the root/shoot ratio in Aohan increasing most significantly. At flowering, the root/shoot ratio was the highest and the effect of water stress the greatest. The abscisic acid (ABA) concentration in the roots of Aohan and Zhongmu No.1 increased under water stress, while in Sanditi there was only a slight or delayed response of ABA concentration.

关键词: abscisic acid     alfalfa     drought response     growth stage     water deficit    

标题 作者 时间 类型 操作

Effects of alfalfa coverage on runoff, erosion and hydraulic characteristics of overland flow on loess

Shufang WU, Pute WU, Hao FENG, G. P. Merkley

期刊论文

Microbial community and functional genes in the rhizosphere of alfalfa in crude oil-contaminated soil

Yi ZHONG, Jian WANG, Yizhi SONG, Yuting LIANG, Guanghe LI

期刊论文

Growth and abscisic acid responses of

Yue LI, Liqiang WAN, Yufei WANG, Xianglin LI

期刊论文