【作者】 王琳琳；

【导师】 孙向阳； 李素艳；

【作者基本信息】 北京林业大学 ， 土壤学， 2014， 博士

【摘要】 土壤盐渍化是限制滨海地区土地资源优化利用的主要障碍,随着滨海地区经济和城市化的快速发展,农林用地面积不断减少,改良和利用盐碱地早已被提上了科学研究日程。基于此,本文在对研究区土壤盐分特征进行本底调查以及室内模拟分析的基础上,采用多种有机改良剂和无机盐分隔离材料对天津滨海盐碱地土壤进行有机改良和生态治理,并评估其造林效果。最终目的是为滨海地区盐渍土改良和沿海防护林营造等林业工程建设提供理论依据和技术支持。主要结果和结论如下：研究区土壤盐分表聚现象严重且总体含盐量较高,土壤呈碱性。土壤中主要盐分组成为氯化钠和氯化钙,而表层土壤中盐分以氯化物和硫酸盐为主。Na+、Cl-和SO42-为研究区0-40cm土层中的主要盐分离子,其三者可反映该地区土壤可溶性盐分离子的变化情况。室内土柱模拟试验表明,利用五种无机材料(沸石、陶粒、河沙、蛭石和海泡石绒)设置的隔盐层能显著降低毛管水上升速率和最大高度,其中沸石和陶粒作为隔盐材料对毛管水的阻滞作用优于传统材料河沙。隔盐材料对土壤水分蒸发抑制率的大小顺序为沸石>陶粒>河沙>蛭石>海泡石绒,随蒸发历时的延长,隔层对水分的抑制作用均有所减弱。不同隔盐处理下的潜水蒸发均为非稳定蒸发。沸石隔盐处理具有最高的土表盐分抑制率,其次是陶粒,但是随蒸发历时的延长,沸石盐分抑制率增加,而陶粒降低。蛭石处理随着蒸发历时的延长,盐分抑制率略有升高；河沙和海泡石绒处理,从蒸发第20d开始到蒸发结束,盐分抑制率保持不变。五种隔盐材料对研究区四种盐渍化特征因子(Cl-、S042-、Na+和Ca2+)向土表的运动过程均具有阻滞作用,但阻滞程度大小各异,并最终在土壤表层形成以氯化物为主的中性盐土。沸石作为隔盐材料能显著降低隔盐层上部土壤盐分离子含量,陶粒的阻水隔盐作用仅次于沸石。沸石隔盐处理下的盐分抑制率大于其水分抑制率,而其他隔盐材料处理下的盐分抑制率均小于水分抑制率,说明水分和盐分的运动具有不同步性。长达四年的大田试验研究表明,在树木种植穴底部和侧壁铺设无机隔盐材料作为隔盐层,可以明显降低土壤盐分含量并显著增加树穴内部土壤水分含量。沸石隔盐处理能显著降低土体内盐分含量,控抑盐效果明显优于其他(陶粒、蛭石和河沙)处理。陶粒处理在40-80cm土层有显著的降盐效果。蛭石处理仅在40-60cm土体内显著降低土壤含盐量。河沙处理降盐效果最差。研究区土壤中主要的盐分离子为Na+、Cl-和SO42-,隔盐层处理能显著降低土壤中各离子含量,并使其在土层中重新分布。此外,隔盐层能有效改善刺槐、国槐、香花槐和红叶臭椿根区土壤物理性质,提高各树种的成活率和保存率,并且明显促进植物生长。可将沸石作为滨海地区剌槐、国槐、香花槐和红叶臭椿隔盐层材料的最优选择。沸石隔盐处理能显著提高刺槐净光合速率(Pn)、蒸腾速率(Tr)、气孔导度(Gs)及叶片水分利用效率(LWUE),降低胞间CO2浓度(Ci)。陶粒处理可显著提高刺槐叶片的Pn、Tr,但改善效果不及沸石,并且其对Gs、Ci和LWUE没有显著影响。与对照相比,河沙处理虽然能显著增加刺槐叶片Pn和Tr,但却导致LWUE显著降低。因此,对于刺槐而言,采用沸石或陶粒作为隔盐层材料,是改善其在滨海盐碱地生长状况的首选。有机液体改良剂(天然高聚物竹醋液)添加能够改善盐碱土理化性质,但效果不是非常显著；并且,不同浓度的竹醋液添加对盐碱地改良效果也不同,其中竹醋液稀释150倍后(处理T2)的改良效果较好,具体体现在,T2处理增加了土壤养分含量,减小土壤容重,增加毛管孔隙度,降低土壤pH值和电导率,促进树木生长。竹醋液对树木生长环境的改善可能是竹醋液多种化学成分综合作用的结果。有机固体改良剂(绿色废弃物堆肥,GWC；莎草草炭,SP；糠醛渣,FR；以上三种有机改良剂的混合物,GSF)极大促进了国槐生长,改良了土壤物理结构,增加了阳离子交换能力(CEC)、有机碳含量和有效养分；降低了盐分含量、电导率(EC)和碱化度(ESP)。在试验末期,与对照相比,GSF处理中的土壤容重、EC和ESP分别下降了11%,87%和71%；总孔隙度和有机碳含量分别增加了25%和96%。GSF处理中的Na+K+含量显著低于其他所有处理。GSF处理中的CEC以及有效氮、有效磷和有效钾含量都显著高于对照,并且他们也是所有处理中最高的。FR处理中的pH值和Ca2+浓度最低,与对照相比,他们各自下降了8%和39%。更多还原

【Abstract】 Soil salinization is a major obstacle to the optimal utilization of land resources. Salt-affected soils are widely distributed throughout the world. The present extent of salt-affected soils substantially restricts plant growth in these areas. It has been demonstrated that leaching with water, chemical amendment, surface mulching with straw and film and phytoremediation are the most often used approaches to ameliorate saline soils. Engineering measures are also an effective solution to control salt movement in saline soil. Establishing soil-isolation interlayer beneath the surface of saline soil is one of the most widely used engineering measures. Even though there are many studies dealing with organic amendments as well as soil-isolation interlayer establishment, very little is known about their effects on saline soil and tree growth. In view of the above, three organic materials (GWC, SP, and FR) and five soil-isolation materials were applied in this study. The aim of the work was to evaluate the effects of different organic amendments and soil-isolation materials on the salinity and fertility of saline soil as well as on plant growth in the coastal areas of northern China. The information obtained from this study will help provide guidance on selection of organic matters in ameliorating coastal saline soil while considering their environmental concerns.The main conclusions are as follows:The saline soil of the study area has high salt content and the salt accumulation phenomenon is serious in the surface of saline soil. The soil surface has low pH values throughout the soil profile, and the salt ions are dominated by chlorides and sulfates. Na+、Cl-and SO42-are the major salt ions of the0-40cm soil layer and they can reflect the changes of dissolved salt ions.The soil column simulation experiment indicated that salt-isolation materials (Zeolite, FS; ceramsite, TL; River sand, HS; Vermiculite, ZS; Sepiolite, HP) can significantly reduce the upward transferring velocity and maximum upward height of the capillary water. FS and TL perform better in preventing the upward transferring of capillary water than HS. The shorter the evaporation time, the better the salt-isolation materials perform in preventing the upward transferring of capillary water. As the evaporation time prolonging, the effectiveness of salt-isolation materials in preventing the upward transferring of capillary water reduces. FS performs best in preventing the upward transferring of soil salt, followed by TL. As the extension of evaporation time, the salt inhibition ratio of FS and ZS increases, while it decreases for TL. The salt inhibition ratio of HS and HP keep constant through the20th day to the end of the evaporation time. All the five salt-isolation materials aforementioned can prevent the upward movement of the four typical salt ions (Cl-, SO42-, Na+and Ca2+) of the study area, but the inhibition ratio of them differs for the salt-isolation materials. In the soil treated with the five materials, the neutral saline soil dominated by chloride comes into being in the soil surface. FS treatment could significantly reduce the salt ions contents of the soil above the salt-isolation interlayers. The inhibition ratio of salt is greater than that of capillary water for FS treatment, while the order is inverse against other materials. This explains the mechanism of controlling salt movement in salinity soil by salt-isolation materials.A four-year experiment was conducted with four treatments:(1) No addition of slat-isolation interlayer (CK);(2) Addition of FS at the bottom and side walls of the planting sites;(3) Addition of TL at the bottom and side walls of the planting sites;(4) Addition of HS at the bottom and side walls of the planting sites. The research was conducted from April2010to August2013at the Coastal Salt-tolerant Plant Science and Technology Park, Dagang, Tianjin, China. All treatments were arranged in a randomized complete block design with four blocks. Each block was again divided into four plots. The four treatments were randomly assigned to each plot within the individual blocks with a separate randomization for each block. The slat-isolation materials were added to nine planting sites in each plot. The nine sites were evenly distributed based on a planting spacing of3m×3m. Each planting site was1m×1m×1m. The results indicated:(1) Slat-isolation interlayers could significantly increase soil water content of tree planting site. FS treatment performed best and had the lowest salt content and salt solute concentration, followed by TL. Relative to the CK, HS had no significant effects on salt content and salt solute concentration.(2) FS treatment significantly increased the leaf photosynthetic rate (Pn), transpiration rate (Tr), stomata conductance (Gs) and leaf water use efficiency (LWUE), and reduced intercellular CO2concentration (Ci). TL treatment can also significantly enhance Pn、 Tr, but it had no significant effects on Gs、Ci and and LWUE. HS treatment had significantly increased Pn and Tr, and reduced LWUE. We concluded that the zeolite was an optimal salt-isolation material in controlling soil salt movement and improving tree growth in the coastal regions.The ability of the following three levels of bamboo vinegar (BV):300-times diluted BV (T1),150-times diluted BV (T2) and50-times diluted BV (T3) to ameliorate saline soil in coastal northern China was investigated from October2012to October2013in a field experiment. Application of bamboo vinegar to saline-alkali soil could improve soil physical structure and chemical characters; but the effects are not significant in comparison with a non-added control. T2treatment performs best in increasing available nutrients, organic matter content and capillary porosity; decreasing soil buck density, pH and EC; and improving tree growth.The ability of the following four organic amendments to ameliorate saline soil in coastal northern China was investigated from April2010to October2012in a field experiment:green waste compost (GWC), sedge peat (SP), furfural residue (FR), and a mixture of GWC, SP and FR (1:1:1by volume)(GSF). Compared to a non-amended control (CK), the amendments, which were applied at4.5kg organic matter m-3, dramatically promoted plant growth; improved soil structure; increased the cation exchange capacity (CEC), organic carbon, and available nutrients; and reduced the salt content, electrical conductivity (EC), and exchangeable sodium percentage (ESP). At the end of the experiment in soil amended with GSF,bulk density, EC, and ESP had decreased by11,87, and71%, respectively, and total porosity and organic carbon had increased by25and96%respectively, relative to the CK. The GSF treatment resulted in a significantly lower Na++K+content than the other treatments. CEC and the contents of available N, P, and K were significantly higher in the GSF-treated soil than in the CK and were the highest in all treatments. The FR treatment resulted in the lowest pH value and Ca2-concentration, which decreased by8%and39%, respectively, relative to the CK. Overall, the results indicate that a combination of green waste compost, sedge peat and furfural residue (GSF treatment) has substantial potential for ameliorating saline soils in the coastal areas of northern China, and it works better than each amendment alone. Utilization of GWC and FR can be an alternative organic amendment to substitute the nonrenewable SP in saline soil amelioration.更多还原