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葛藤生长对干热河谷冲沟沟崖土壤性质的影响研究
Alternative TitleStudy on the Effcet of Kudzu Growth on Soil Properties in the Gully Bank in Dry-hot valley Region
校亮
Subtype硕士
Thesis Advisor熊东红
2017
Degree Grantor中国科学院大学
Place of Conferral北京
Degree Discipline土壤学
Keyword葛藤覆被 冲沟沟岸 土体性质 干热河谷
Abstract干热河谷区是我国西南地区特殊的生态脆弱区,其气候炎热干燥、水土流失严重、土层贫瘠浅薄、植被恢复困难,尤其是土体裸露陡立、水分蒸发严重、昼夜温差剧烈的冲沟沟岸,更是植被恢复极端困难区,长期以来一直未能找到有效的植被恢复措施。本研究采用野外定位监测、室内实验和理论分析相结合的方法,选取裸露沟岸作为对照,依据藤本生物量设置4个葛藤覆被沟岸处理,开展葛藤生长对冲沟沟岸土体水热状况、理化性质及微生物特性的影响研究,以揭示葛藤生长对改善沟岸恶劣生境、促进植被恢复的机理,取得的主要研究结论如下:葛藤覆被对沟岸土体水热状况的影响沟岸土体水热状况受葛藤覆被类型(鲜/枯藤)以及葛藤覆被物生物量共同影响,整体而言,枯藤覆被有益于保持其下沟岸土体水分,且土壤水分状况随枯藤覆被量的增加而提升,鲜藤覆被反而加重了其下沟岸土壤的水分亏缺程度。鲜、枯藤覆被均有助于平抑其下沟岸土壤温度变化幅度和变异程度,具体而言,相比裸露沟岸:(1)枯藤覆被有益于保持其下1 m的沟岸土体含水率(21.94%—25.12%),鲜藤覆被下沟岸土体含水率(13.92%)则明显减小。(裸露沟岸土体含水率为19.73%)。(2)枯藤覆被有益于缓解其下沟岸30—60 cm土层的土体水分亏缺程度(土壤含水率介于27.57%~31.41%之间),鲜藤覆被反而加重了其下沟岸土体水分亏缺程度(土壤含水率仅为12.97%)。(裸露沟岸30—60 cm土层土壤含水率为24.51%)(3)鲜、枯藤覆被均可增加水分补给阶段沟岸表层0—10 cm土壤含水率的增加量,降低水分衰减阶段沟岸表层0—10 cm土壤含水率的散失量。在枯藤覆被沟岸,增加枯藤覆被量可保证沟岸表层土壤含水率变化率以较高的增长速率、较为平稳地、较长时间地增长。(4)鲜、枯藤覆被均可有效平抑沟岸表层土壤温度,且随葛藤覆被量增加,沟岸表层5 cm、10 cm处土壤温度的变化幅度和变异程度均逐渐减小。葛藤覆被对沟岸表层土壤性质的影响沟岸表层土壤性质受葛藤覆被类型(鲜/枯藤)以及葛藤覆被物生物量共同影响。整体而言,鲜、枯藤覆被均有助于提升其下沟岸土壤毛管孔隙度;鲜藤覆被下沟岸土壤养分含量普遍降低,枯藤覆被下沟岸土壤养分含量则整体增加;鲜、枯藤覆被均有助于提升其下沟岸土壤微生物总PLFA量。具体而言,相比裸露沟岸:(1)鲜藤覆被沟岸表层土壤容重相对减小(土壤容重减小了3.92%),而枯藤覆被沟岸表层土壤容重反而增加(土壤容重增加了3.15%—9.76%);鲜、枯藤覆被沟岸表层土壤毛管孔隙度均有所增加(土壤毛管孔隙度分别提升了18.85%、8.18%—10.17%),且差异显著。(2)鲜、枯藤覆被沟岸表层土壤全盐含量均有所增加(土壤全盐含量分别增加了199.45%、66.08%—204.16%),且差异显著。(3)整体而言,鲜藤覆被沟岸表层土壤土壤养分含量(有机质、铵态氮、有效磷等)相对减少,枯藤覆被沟岸表层上述土壤养分含量则普遍增加。(4)鲜、枯藤覆被沟岸表层土壤总PLFA量普遍提升(10.5倍、2.6—6.5倍),尤其以鲜藤覆被沟岸表层土壤总PLFA量提升最为明显。(裸露沟岸总PLFA量3.24nmol/g)(5)葛藤不同覆被状况下沟岸表层土壤总PLFA量在雨季普遍高于旱季。且各类土壤微生物对于旱、雨季变化、葛藤覆被状况响应均不同。葛藤覆被对沟岸土体性质的影响机理葛藤覆被沟岸之后,主要通过以下途径作用于沟岸土壤。其一,通过覆层持水和遮蔽降温改变沟岸土壤水热状况;其二,通过须根作用及残体分解影响沟岸表层土壤孔隙状况和养分含量。(1)研究发现,土壤热参数在葛藤覆被沟岸前、后均表现出随土壤含水率的增加呈现出相反的变化规律。差异产生的原因在于葛藤覆被差异→土壤含水率不同→热传导方式改变→土壤热特性参数变化→土壤温度变化。裸露沟岸土壤水分亏缺(5%~13%),土壤热传导主要通过固/固途径;葛藤覆被沟岸土壤水分条件得以提升(15%~30%),土壤热传导改变为以固/固、固/液途径为主。热传导方式的改变通过影响土壤热参数变化进而引起土壤温度变化。(2)沟岸表层土壤性质间互为影响、相互作用。沟岸表层土壤容重与有机质含量、速效钾含量高度负相关;总孔隙度与毛管孔隙度、微生物总PLFA量高度正相关;非毛管孔隙度与细菌含量高度正相关、与放线菌含量高度负相关。即土壤各性质之间是相互影响、互馈互作、协同变化的。基于上述葛藤生长对干热河谷冲沟沟岸土体性质的影响研究,在葛藤逐年生长覆被沟岸的进程中,试验沟岸经历裸露→鲜藤覆被→枯藤覆被→枯藤逐年累积等阶段。在鲜藤覆被沟岸阶段,土壤水分状况、养分含量呈现出阶段性地降低;在有枯藤覆被沟岸至以后的阶段,土壤土壤水分状况、养分含量则逐年提升。因此,试验葛藤可作为干热河谷冲沟沟岸生境改良的有效措施,建议将葛藤种植在沟岸底部水肥条件适宜部位,通过攀沿覆被沟岸,并在逐年累积的过程中,优化调控沟岸土壤水热条件、养分状况、微生物活性等,为其它物种着床生长创造条件。
Other AbstractSoil erosion is an extremely serious environment problem due to gully erosion in Yuanmou Dry-hot valley. It is a typical ecologically fragile region in western of China, soil moisture and temperature changes sharply in the gully bank of the Dry-hot Valley Region, and vegetation restoration is extremely difficult measures in this area. Previous vegeration restoration practice has innored the gully bank. In this study, based on field investigation and situ observation in the gully bank under the coverage of Kudzu, we set four treatments based on the biomass of Kudzu cover (T1: 309.70g/m2 fresh Kudzu; T2, T3, and T4: 594.34, 1103.43, and 1693.27g/m2 withered Kudzu, respectively), and used plots without Kudzu coverage as control. The effect of the different extents of Kudzu coverage on soil properties in the gully bank were studied in situ. And we have drawn our conclusions by studying on the mechanism of the effect of Kudzu growth on soil properties in the gully bank in Dry-hot valley Region. The results indicate that: Effect of Kudzu growth on soil water content and soil temperature in the gully bankThe soil hydrothermal condition of gully bank is closely related to the type of the Kudzu cover and the biomass of the cover. In this regard, the withered cover is conducive to the conservation of the soil water, and with the increase of the withered cover biomass, the soil water shows a growing trend. However, the fresh cover increases the shortage status of the soil water in gully bank. Additionally, the fresh and withered cover is helpful to limit the change of the soil temperature. (1) In 0-100cm depth of soil layer, it is beneficial to soil water conversation (21.94%~25.12%) within the withered coverage of Kudzu in the gully bank, however, within the fresh coverage of Kudzu in the gully bank, it significantly decrease the soil water content (13.92%) compared with the bare gully bank (19.73%).(2) In 30-60 cm depth of soil layer, compared with the bare (24.51%) valley bank, it is beneficial to relief water aridity (27.57%~31.41%) in 30-60cm layer of soil. However, fresh Kudzu aggravates the condition (12.97%).(3) In the soil moisture-supplying period, the soil moisture increase in the gully bank of the surface layer (0—10 cm) with the increase of Kudzu biomass. However, the rate of soil moisture loss decrease in the gully bank of the surface layer (0—10 cm) with the increase in Kudzu biomass during this period. Furthermore, with the increase in biomass of withered Kudzu, the rate of soil moisture waveform reduces fluctuation decrease, and wavelength increase.(4) With the increase in the biomass of Kudzu, soil temperature fluctuation decreased in the gully bank of the surface layer both in 5cm and 10cm.Effect of Kudzu growth on soil properties in the gully bank of the surface layerThe soil property of bank surface is affected by the type of the Kudzu cover and the biomass of the cover. In this regard, the fresh and withered cover is conducive to the growth of the capillary pore; the nutrient of the fresh cover decreases obviously, and the nutrient value increases in withered cover bank; additionally, the fresh and withered cover is conducive to increase the PLFA of the microorganism.(1) The bulk density of top soil relatively decrease (3.92%) in the gully bank which is covered with fresh Kudzu. However, the bulk density increase (3.15%—9.76%) in the withered Kudzu. Compared with the bared valley bank, he capillary pore of both the withered and fresh coverage of Kudzu in gully bank increase (18.85%、8.18%—10.17%) significantly.(2) Compared with the bare gully bank, the soil total salt of both the withered and fresh coverage of Kudzu in the gully bank significantly increase (18.85%、8.18%—10.17%). (3) Compared with the bared gully bank, the soil organic matter, NO3-N of top soil of both within the withered and fresh coverage of Kudzu in gully bank change significantly. It behaves as follows, they decrease in gully bank with the coverage of fresh Kudzu and increase in gully bank with the coverage of withered Kudzu.(4) Compared with the bared gully bank, the PLFA of both within the withered and fresh coverage of Kudzu in the gully bank universally increase (10.5 times、2.6—6.5 times), especially in the top soil in gully bank with the coverage of fresh Kudzu. (5) In the surface layer of gully bank, the content of total PLFA in rainy season is higher than that in dried season. And different soil microbes respond differently to dry-rainy season and Kudzu cover condition.Mechanism of the effect of Kudzu growth on soil properties in the gully bankKudzu cover has an impact on the soil mainly by two patterns. For one thing, it keeps the soil moisture and prevents the soil from direct solar radiation which could decrease the soil heat, and change the whole condition of the soil. For another, the Kudzu cover changes the soil porosity and nutrition condition by fibril effect and residue decomposition.Soil thermal parameter showes opposite laws to soil moisture content at front and back gully bank with the coverage of Kudzu. The difference of Kudzu cover leads to the difference of soil moisture content and further changes the patterns of heat exchange. That changes the soil thermal parameter which ultimately changes the soil heat. At the bared bank, soil moisture is shortage (5%~13%), which causes the heat conduction mainly based on solid patterns. However, the gully bank with the coverage of Kudzu could changes the solid and liquid patterns, which could increase the soil moisture content. In a ward, the heat conduction changes the soil heat by changing the soil thermal parameter.Different soil properties influence interaction at top soil. For instance, the soil bulk density, organic matter and available potassium show a significant negative correlation. But the soil total porosity, capillaryporosity and microbial PLFA show a significant positive correlation. The soil non-capillaryporosity and bacteria content shows a significant positive correlation, but shows a negative correlation with actinomyces content. All of these processes embrace the reality that soil properties behavior affects one another. Based on the study of the impact of Kudzu growth on the soil property, we draw the conclusion: during the process of the growth of Kudzu, the experimental bank experiences the following stages: bare bank —fresh cover bank—withered cover bank—accumulation withered cover. In the stage of the fresh Kudzu cover bank, the soil water and the nutrient decrease by phases; from withered Kudzu cover stage, the soil water and nutrient increase year by year. Consequently, the experimental Kudzu can be an efficient measure to improve the habitat. And we suggest that the bottom position is the good place to plant Kudzu because of the condition of water and fertility. The long-term growth of Kudzu will improve the hydrothermal status, nutrient status and microbial activity, which will create a favorable conditions for other plants. 
Pages102
Language中文
Document Type学位论文
Identifierhttp://ir.imde.ac.cn/handle/131551/24571
Collection山地灾害与地表过程重点实验室
Affiliation中国科学院成都山地灾害与环境研究所
First Author Affilication中国科学院水利部成都山地灾害与环境研究所
Recommended Citation
GB/T 7714
校亮. 葛藤生长对干热河谷冲沟沟崖土壤性质的影响研究[D]. 北京. 中国科学院大学,2017.
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