【作者】 李洪波；

【导师】 王林和；

【作者基本信息】 内蒙古农业大学 ， 水土保持与荒漠化防治， 2010， 博士

【摘要】 凝结水是半干旱地区生态系统重要的水源,本文以内蒙古农业大学科技园区牧草地试验站和毛乌素沙地开发整治研究中心为试验基地,在2007～2009年期间,应用自制微型测渗计称重法、离体枝条法、人造凝结面法、压力室法、封袋法和盆栽干旱胁迫等方法对土壤凝结水特征,植物冠层凝结水特征,凝结水对臭柏(Sabina vulgaris)、油蒿(Artemisia ordosica)和籽蒿(Artemisia sphaerocephala)水分特性的影响等方面进行了研究。取得如下结果:1.半干旱地区土壤表层凝结水由吸湿水,大气水汽凝结水和土壤深层水汽凝结水组成。土壤凝结水主要发生在土壤表层0～2cm和2～4cm,土壤表层0～2cm和2～4cm凝结量与0～10cm凝结量呈现线性正相关关系。大气中水汽对土壤表层(5cm)凝结水的贡献率远小于深层土壤水汽的贡献率,二者比值为3.1:10～4.5:10。随着土壤表层凝结量的降低,大气水汽对土壤凝结水的贡献将增大,深层土壤水汽的贡献将减小,在干旱季节,二者最大比值为8:10。大气中的水汽总是先于土壤中的水汽到达和离开土壤表层。2.土壤凝结水量随着季节发生变化,雨季土壤凝结水量与蒸发量均大于旱季。当日凝结量和次日蒸发量呈现显著的线性正相关系关系(y=0.947x+0.0103,R2=0.9454,n=348,P<0.05)。初始土壤(粟钙土)表层含水量与含水量增量呈现极显著的线性负相关关系(y=-0.2618x+0.7192,R2=0.5609,n=51,P<0.0001)。土壤中所含小粒径沙粒和物理性粘粒越多越有利于土壤吸湿凝结水的形成,吸湿凝结能力大小为臭柏样地土样>油蒿样地土样>裸地样地土样>风成沙土。3.植物覆盖有助于土壤吸湿凝结水的形成,在毛乌素沙地,冠层凝结能力的大小为臭柏冠层>油蒿冠层>裸地。臭柏冠层内垂直高度相对湿度达到100%持续时间从大到小依次为100cm、50cm、150cm和5cm。臭柏冠层内人造凝结面与离体枝条拦截凝结水的能力差异不显著,均与凝结持续时间呈线性正相关关系。2009年5~9月植物生长期内,臭柏冠层内的PVC凝结盘均能够拦截到凝结水,垂直高度凝结量差异不显著,雨季和旱季最大日均拦截量分别为0.0994mm和0.0086mm。臭柏冠层内PVC凝结盘凝结水量与冠层下土壤凝结水量相关性显著。4.雨季和旱季影响土壤吸湿凝结量的主导气象因子分别是相对湿度和绝对湿度。臭柏冠层内PVC凝结盘凝结量与12h夜间平均温度呈现极显著负相关关系,与24h平均相对湿度、12h夜间平均相对湿度和达到露点时间呈现极显著正相关关系。5.凝结水对臭柏、油蒿、籽蒿离体枝条和盆栽苗木枝条的水分特性影响显著,凝结水能够维持或提升枝条的水势,增加枝条相对含水量,在室内喷雾封袋后臭柏、油蒿和籽蒿枝条水势平均12h增量分别为0.0454～0.1646MPa、0.1725～0.3466MPa和0.6553～0.7792MPa;相对含水量平均12h增量分别为0.92%～3.01%、2.47%～4.68%和1.57%～4.95%。更多还原

【Abstract】 Condensation water is important water source in semiarid Ecosystems. We used homemade micro-lysimeter, detached shoots, artificial condensation surface, pressure chamber and plants of drought stress to determined characteristics of soil condensation water, characteristics of canopy condensation water, and condensation water’s effect on water characteristics of Sabina vulgaris, Artemisia ordosica and Artemisia sphaerocephala from 2007 to 2009 at the test base of Grassland Experimental Station of Science and Technology Park of Inner Mongolia Agriculture University and Mu Us Sandland Development and Research Center. The results showed as follows:1. There were three kinds of water vapor source, water vapor of direct adsorption by soil from air, condensation water from air and water vapor from the lower soil layer about condensation water of soil in Semi-arid areas; Condensation water of soil is mainly occurred at 0~2cm and 2~4cm of soil surface,there was linear positive correlation between condensation volume of 0~2cm, 2~4cm and condensation volume of 0~10cm.The contribution rate of water vapor from air was smaller than from lower soil layer to upper 5cm soil condensation water, their contribution ratios usually were from 3.1:10 to 4.5:10.When condensation volume of soil surface reduced , the contribution rate of water vapor from air would increased and the contribution rate of lower soil layer would reduced , their maximum contribution ratio was 8:10 in the dry season. Water vapor from air always condensated and evaporated earlier than water vapor from lower soil layer at upper 5cm soil layer.2. Soil condensation water would change with the seasons, condensation volume and evaporation volume of soil condensation water was higher in the rainy season than in the dry season,a strong and significant linear positive correlation was found between today’s condensation volume(x) and next day’s evaporation volume(y), their equation was y=0.947x+0.0103(R2=0.9454,n=348,P<0.05). There was linear positive correlation between initial soil water content and increasing of soil surface moisture,their equation was y=-0.2618x+0.7192(R2=0.5609,n=51,P<0.0001). If soil contained more and more small particle sand and physical clay, which would help the formation of condensation water of soil, condensation ability of the soil from big to small was undisturbed soil of Sabina vulgaris’s plot, undisturbed soil of Artemisia ordosica’s plot, undisturbed soil of bare land’s plot, and aeolian sandy soil.3. Where there were more plant-covered will help the formation of condensation water of soil. In Mu Us Sandland, condensation ability of the canopy from big to small was Sabina vulgaris, Artemisia ordosica and bare land. Duration ability of 100% relative humidity from big to small were 100cm, 50cm,150cm and 5cm in the vertical height of Sabina vulgaris canopy. There were no significant difference between the ability of intercepting condensation water of artificial condensation surface and detached shoots’of Sabina vulgaris, the intercepting volumes of condensation water by artificial condensation surface and detached shoots of Sabina vulgaris were linear positive correlation with condensation water’s duration. PVC condensation plate of Sabina vulgaris canopy were able to intercept condensation water from May to September in 2009, the biggest rainy season’s intercepting volume was 0.0994mm and the biggest dry season’s intercepting volume was 0.0086mm. Condensation volume of Sabina vulgaris canopy was significantly correlated with condensation volume of soil.4. Relative humidity was the main meteorological factor that will effect the formation of soil condensation water in rainy season, and absolute humidity was the main meteorological factor that will effect the formation of soil condensation water in dry season. Condensation volume of PVC condensation plate was significantly positive correlated with 24h average relative humidity and 12h average relative humidity of night, and was significantly negatively correlated with 24h average temperature and 12h average temperature of night.5. Condensation water’effects on the moisture characteristics of Sabina vulgaris,Artemisia ordosica and Artemisia sphaerocephala were significant, it could keep and enhance water potential and relative water content of shoots. After spraying fog and sealing bag indoors, the average water potential increment of Sabina vulgaris,Artemisia ordosica and Artemisia sphaerocephala were 0.0454~0.1646MPa/12h, 0.1725~0.3466MPa/12h and 0.6553~0.7792MPa/12h, respectively; the average increment of relative water content of were 0.92%~ 3.01%/12h, 2.47%~4.68%/12h and 1.57%~4.95%/12h, respectively.更多还原