【作者】 刘月梅；

【导师】 张兴昌；

【作者基本信息】 西北农林科技大学 ， 环境科学， 2013， 博士

【摘要】 EN-1固化剂是一种由多种无机和有机材料组成的复合材料，可通过与土壤发生理化反应达到胶结土粒、增加土体稳定性的作用，应用领域广泛，已逐步应用于黄土边坡生态防护，具有良好的应用前景。本研究通过室内模拟试验和盆栽试验，系统地研究了EN-1固化剂对黄土地区典型土壤的结构、持水性等水分特征及黑麦草生长的影响，并分析了固化土物理性质与黑麦草生长调节机制之间的相互关系，确定了适于黄土边坡生态防护的土壤容重和固化剂掺量。主要结论如下：1、对固化土壤的结构研究表明：室内土柱试验条件下，相同容重不同固化剂掺量处理各粒径团聚体含量普遍高于素土，但处理间无显著性差异；固化剂处理10d后提高了土壤中>0.25mm水稳性团聚体含量。盆栽试验各处理不同粒径团聚体分布趋势与室内土柱试验基本一致，固化黄绵土>0.25mm水稳性团聚体含量在10%～20%之间，而固化塿土在50%以上，均显著高于室内土柱试验；水分胁迫有利于固化土>0.25mm水稳性团聚体形成，且随着盆栽时间延长，固化土壤结构更加稳定；固化剂掺量在0.05%和0.10%时>0.25mm水稳性团聚体含量相对较高，土壤结构较素土稳定；不同水分条件下，>0.25mm水稳性团聚体含量与团聚体平均重量直径、几何平均直径呈显著正相关，与分形维数呈显著负相关，不同处理对塿土土壤结构的影响较黄绵土明显。2、对固化土壤水分特征研究表明：不同处理土壤水吸力与对应土壤含水量的关系均符合方程θ=a·S-b所表示的幂函数关系；固化剂降低了土壤的持水能力，但对土壤有效水含量影响不显著。固化剂有利于土壤导水能力的提高，黄绵土和塿土固化剂掺量分别在0.05%～0.10%和0.15%～0.20%范围内具有最大入渗能力；无论土壤中是否加入固化剂，随着土壤容重增加，土壤饱和导水率均降低。固化黄绵土在蒸发初期土壤水分急剧减少，后期趋于缓慢，不同固化剂掺量处理对累积蒸发量影响不显著；固化塿土土壤水分蒸发速度较固化黄绵土平缓，且不同固化剂掺量处理间表现出显著性差异（P<0.05）；固化土累积蒸发量均低于素土。3、对固化土壤水分垂直入渗特征研究表明：土壤容重对固化土的入渗能力有较大影响，土壤容重越大，对应于同一时刻入渗率越低，累积入渗量越小，湿润锋推进距离越短。固化剂对累积入渗量和湿润锋运移距离的影响均显著（P<0.05），且随固化剂掺量增大，累积入渗量和湿润锋运移距离均有先增大后减少的趋势；累积入渗量与湿润锋运移距离呈良好的线性关系；黄绵土和塿土固化剂掺量分别在0.05%～0.10%和0.05%～0.15%范围内累积入渗量最大。适宜的固化剂掺量可以加快土壤水分入渗，增加土壤含水量，但当固化剂掺量增加到一定程度时，反而会抑制土壤水分入渗，这种抑制作用在高土壤容重下表现更为明显。利用Philip模型、Kostiakov经验公式和指数公式对固化黄绵土和固化塿土入渗率与入渗历时的关系进行拟合时发现，Kostiakov公式拟合值更接近于实测值，且土壤容重越大，拟合精度越高。4、揭示了固化土壤环境下黑麦草生长调节机理，研究发现：随土壤容重增加黑麦草叶绿素含量、根系活力、根冠比和生物量均降低，而固化土壤各指标值均高于素土，且随固化剂掺量的增加呈先增加后降低的趋势。轻度水分胁迫下，固化剂掺量在0.05%～0.20%范围内，较大的固化剂掺量对黑麦草的生长产生了一定胁迫，导致黑麦草叶片相对含水量和叶绿素含量降低，而可溶性糖、可溶性蛋白、脯氨酸和丙二醛含量增加。轻度水分胁迫下，黑麦草根系活力、土壤持水能力、土壤有机质含量、>0.25mm水稳性团聚体含量和饱和导水率是影响黑麦草生物量的主要因子；充分灌水条件下，土壤有机质、0.25mm水稳性团聚体含量和根系活力则是影响黑麦草生物量的主要因子，与土壤持水、供水、导水、蒸发等相关性不显著。5、EN-1固化剂与N肥配施研究发现：固化剂与N肥配施条件下，不同固化剂掺量对黑麦草株高、分蘖数、根系特征影响显著（P<0.05），固化土各指标值普遍高于素土，但与固化剂掺量不成正比；随土壤容重增大，黑麦草根表面积、根长和根密度均逐渐降低。黄绵土不同固化剂掺量处理对水分利用效率影响不显著，塿土随固化剂掺量增加水分利用效率呈先增后降的趋势。固化剂、N肥与土壤容重三因素一次项及二次项对黑麦草生物量均有极显著影响(P<0.01)；土壤容重与固化剂交互作用明显。黄土边坡生态防护黄绵土最适容重为1.3g/cm3、固化剂掺量为0.15%，而塿土容重为1.35g/cm3、固化剂掺量为0.10%。更多还原

【Abstract】 EN-1ionic stabilizer is an excellent geocomposite, which is made of variety of inorganicand organic materials. It can cement soil particles and increase the stability of soil by physicaland chemical reaction with soil. Therefore, it has been gradually applied to ecologicalprotection of the side slope of Loess. In this paper, the effects of EN-1soil stabilizer on soilstructural characteristics, soil water retention, and physiological characteristics of ryegrasswere analyzed. The influences of coupled utilization of EN-1stabilizer and nitrogen fertilizeron growth and root characteristics of ryegrass and the water use efficiency were also analyzed.The main conclusions are as follows:1. The structural characteristics research of stabilized Loess soil indicate that the particlesize aggregate contents of different stabilizer amendment amount treatments under the samesoil bulk density have no significantly different in indoor soil column experiment. Largeparticle size aggregates contents of stabilized soil are higher than the control. Water-stableaggregates contents (d>0.25mm) of stabilized soil increase after10days curing. The structureof stabilized soil is more stable than the control. The distribution trend of different particlesize aggregate under different treatments of Loess soil in potted trial is similar to the indoorexperiment. The content of the water-stable aggregates (d>0.25mm) of different treatments isbetween10%~20%for Loessial soil, but more than50%for Lou soil. The water-stableaggregates content of different treatments in potted trial is significantly higher than that inindoor experiment, respectively. The stability of soil structure improves with the growth ofryegrass. The water-stable aggregates contents (d>0.25mm) is relatively higher when the soilstabilizer amendment addition is0.05%～0.10%under the same soil bulk density amount.There are significantly positive correlations between the water-stable aggregates contents(d>0.25mm) of Loess soil and the mean weigh diameter (MWD), geometric mean diameter(GMD). Meanwhile, there is a significantly negative correlation between the water-stableaggregates contents (d>0.25mm) and the fractal dimensions (D). Correlation coefficientsindexes of Lou soil are higher than Loessial soil. The influence of different treatments of Lousoil on soil structure is more obvious than that of Loessial soil. Soil structure of Lou soil ismore stable than Loessial soil. 2. Effects of EN-1stabilizer on the moisture characteristics of Loess soil show that therelationship between moisture content and soil water suction of different treatments of Loesssoil can be described by the function θ=a·S-b. The correlation coefficient of differenttreatments is highly significan（tP<0.01）for Loessial soil but significan（tP<0.05）for Lou soil.Compared to the control, EN-1stabilizer just slightly reduces the soil water-holding capacity.The stabilizer has no significantly influence on the soil effective water. EN-1stabilizer couldincrease soil hydraulic conductivity capacity, but there is not a positive correlation betweenthe capacity and the amount of soil stabilizer. The saturated hydraulic conductivity has thehighest value when the contents of stabilizer at0.05%～0.10%for Loessial soil, but at0.15%～0.20%for Lou soil. The soil saturated hydraulic conductivity decreases withincreasing soil bulk density of Loess soil whether the soil is stabilized or not. Evaporation rateof soil water of different treatments under the same soil bulk density of Loessial soildramatically reduces first but slowly reduces then. The moisture evaporation rate of Lou soilis slower than Loessial soil. The effects of different stabilizer amendment amount under thesame soil bulk density of Lou soil on cumulative evaporation show significant difference（P<0.05）, but there is not a positive correlation between the cumulative evaporation and thestabilizer content.3. The infiltration characteristics of Loess stabilized soil prove that the soil bulk densityhas significant influence on infiltration capacity at1.2～1.4g/cm3for Loessial soil and1.3～1.5g/cm3for Lou soil. The influence of soil bulk density on infiltration rate is stable andconstituent. Cumulative infiltration decreases with increasing soil bulk density. The stabilizeramount has effects on cumulative infiltration and wetting front under the same soil bulkdensity of Loess soil. The cumulative infiltration show the highest value at0.05%～0.10%amount of EN-1stabilizer for stabilized Loessial soil, and at0.05%～0.15%for stabilizedLou soil. There is a good linear relationship between the amount of cumulative infiltration andthe wetting front distance of stabilized Loess soil. The cumulative infiltration and wettingfront increase first and decrease then with increasing amount of EN-1stabilizer. Kostiakovformula is more accurate than other models when fitting the relationship between infiltrationrate and time with Philip model, Kostiakov empirical formula and index formula.4. The chlorophyll content, root activity, root/shoot ratio, root biomass and plant biomassdecrease gradually with increasing soil bulk density ranged from1.2～1.4g/cm3of Loessialsoil and1.3～1.5g/cm3of Lou soil. They increase first, and then decrease with increasingstabilizer content under the same soil bulk density of Loess soil, but all of the values are allhigher than the control. Higher stabilizer contents ranged0.05%～0.20%stress on ryegrassgrowth under low water stress conditions. Relative moisture content and chlorophyll content of ryegrass decrease, while soluble sugar content, soluble protein content, proline content andMDA content of ryegrass increase. The path analysis on the relationship between the ryegrassbiomass and indexes of soil physical and ryegrass physiological indicates show that rootactivity, water holding capacity, soil organic matter,>0.25mm water-stable aggregatescontent and hydraulic conductivity are the dominant factors on ryegrass biomass under minorwater stress conditions, but soil organic matter content,>0.25mm water-stable aggregatescontent and root activity are the dominant factors on ryegrass biomass under filling irrigationconditions. Correlations between water supply capacity, hydraulic conductivity, soil waterevaporation capacity and ryegrass biomass are not significant under filling irrigationconditions.5. Effects of EN-1stabilizer on the growth and root characteristics of ryegrass show thatthe different stabilizer amount have significant effects on height, tillers number and rootcharacteristics of ryegrass under EN-1stabilizer combined nitrogen fertilizer conditions.Height, root length and root area of ryegrass are all higher than the control. The effects ofdifferent nitrogen fertilizer amount on ryegrass biomass are not significant for Loessial soil.The root biomass, total biomass, root length and root area of ryegrass gradually increase withincreasing nitrogen fertilizer amount for Lou soil. The root area and root length of ryegrassgradually decrease with increasing soil bulk density for Loess soil. The effects of stabilizerand nitrogen on water use efficiency of ryegrass are not significant for Loessial soil. Thewater use efficiency of ryegrass increases first and decreases then with increasing stabilizeramount, and gradually increases with increasing nitrogen fertilizer for Lou soil. The linear andquadratic of soil bulk density stabilizer and nitrogen fertilizer have significant effects onryegrass biomass (P<0.01). There are highly significant correlations between ryegrassbiomass and soil bulk density, stabilizer content and nitrogen fertilizer content in a form ofnegative quadric curved lines relations. There is a certain interactive effect between soil bulkdensity and stabilizer on the ryegrass biomass by response surface and regression analysis.The best soil bulk density and stabilizer ratio is1.3g/cm3and0.15%for Loessial soil, and is1.35g/cm3and0.10%for Lou soil, respectively.更多还原