文章摘要
戴矜君.草被覆盖对养分迁移机制的影响[J].水土保持学报,2016,(3):
草被覆盖对养分迁移机制的影响
Impact of vegetation cover on nutrient transportation mechanism
投稿时间:2016-01-18  修订日期:2016-03-09
DOI:
中文关键词: 模拟降雨试验  全株植物  地下部分  养分迁移  动态变化
英文关键词: simulated rainfall experiment, complete plant, underground part, nutrient transportation, dynamic change
基金项目:林业公益性行业科研专项经费(201404209)基于生态安全的水土保持措施空间配置技术,北京高等学校青年英才计划(YETP0750)北方土石山区坡面侵蚀水动力学机理研究
作者单位邮编
戴矜君 北京林业大学 100083
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中文摘要:
      为探讨草被覆盖对养分流失机制的影响,采用室内模拟降雨试验,在30mm/h雨强下,对不同水土保持先锋植物种(紫花苜蓿、狗尾草)、四种植株密度(0、80、120、160株/m2)、两种处理方式(保留整株植物、仅保留地下部分)下养分随泥沙和径流流失浓度与流失总量进行研究。结果表明:草被覆盖能有效控制坡面侵蚀,其中紫花苜蓿和狗尾草植株控制土壤侵蚀作用与地下部分关系密切,地上部分作用不明显。裸坡养分随泥沙的流失量是有植被坡面的1.49~5.90倍(全氮)、1.24~8.61倍(全磷)、1.17~1.82倍(速效钾),但两者的流失浓度差异不显著,表明草被控制养分随泥沙流失作用主要来源于控制侵蚀量,其中狗尾草地下部分减少养分随泥沙流失的作用强于紫花苜蓿,紫花苜蓿地上部分减少养分流失的作用强于狗尾草;同时随植株密度增加,草被地下部分减少养分随泥沙流失的作用逐步增强。草被覆盖能有效减少坡面养分随径流流失,地下部分坡面与全株坡面的全氮流失量比值为1.02~1.05(狗尾草)、1.10~1.14(紫花苜蓿),表明草被控制养分随径流流失作用主要来源于地下部分,其中狗尾草地下部分作用较紫花苜蓿明显;同时随植株密度增加,地下生物量控制全氮和全磷养分随径流流失的作用逐步强化;,但地下部分控制速效钾流失作用的权重没有明显的定向变化。径流养分浓度动态变化前期不断下降,后期趋于稳定,其中幂函数对养分浓度动态变化的拟合效果最佳;同时全氮和全磷动态变化与植株状况关系密切,而全磷对植株状况变化响应不明显。
英文摘要:
      In order to reveal mechanism of nutrient transfer ,two plant (alfalfa and green foxtail), four plant density (0, 80, 120,160 plants square metre), two treatment(complete plantlet and underground biomass)was carried out by simulated rainfall experiment. The results showed that: grass could control erosion effectively, which the effect of plant to reduce erosion was related to the underground biomass closely and the effect of aboveground biomass was not significant. Nutrient Loss with erosion of bare slope was 1.49~5.90 times (total nitrogen), 1.24~8.61 times (total phosphorus), 1.17~1.82 times (available potassium) than vegetated slopes, however, concentration difference of nutrient loss with erosion between bare slope and vegetated slopes was not obvious. Grass controlled nutrient loss with erosion by reducing the amount of sediment mainly, which underground part of foxtail was more effective than alfalfa and aboveground biomass of alfalfa was more effective than foxtail. Meanwhile the role of underground part to reduce nutrient loss was gradually significant with the plant density increased. Grass could reduce the nutrient loss with runoff effectively, and the total nitrogen loss ratio of slope with underground biomass and complete plants was 1.02~1.05 (green foxtail), 1.10~1.14 (alfalfa), indicated grass control nutrient losses with runoff mainly by underground parts, which underground biomass of foxtail was more effective than alfalfa. With the plant density increase, effect on controlling total nitrogen and total phosphorus loss with runoff by underground biomass gradually strengthened but the available potassium didn’t have significant change. The dynamic change of runoff nutrient concentration decreased, than remain stable, which the power function best fit. The change process of total nitrogen and total phosphorus were related to plant situation closely, and total phosphorus changed with plant was not obvious.
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