【作者】 张雪梅；

【导师】 吕光辉；

【作者基本信息】 新疆大学 ， 生态学， 2011， 硕士

【摘要】 新疆是我国盐渍土分布面积最大、范围最广、类型最全的省区,也是世界上盐渍土分布比较集中的地区。新疆广袤的盐渍化土地为盐生植物提供了生物多样性生存和维持的基础,同时也使得新疆的盐生植物多样性具有了明确的干旱区地域特色。艾比湖湿地自然保护区具有十分丰富的盐生植物多样性,占新疆盐生植物种的40.2%,且以干旱生境下居多。近年来环境变化引起的土地荒漠化、盐渍化日益严重,对地球生物多样性造成了严重影响,盐生植物对维持干旱区盐渍土的生态平衡、盐渍土改良利用,以及遏制土地荒漠化、维持地球生物多样性和促进全球生态良性循环有着不可替代的重要作用,且众多的盐生植物中不乏经济价值高、开发潜力大的资源植物。对艾比湖湿地自然保护区内干旱生境下盐生植物的土壤氮素进行了初步探讨,为此地区盐渍化改良提供基础依据和数据支持。本文通过对所选取的9种不同盐生植被覆盖样地土壤氮素特征的初步研究,得出以下结论:(1)土壤氮素形态时空动态变化特征。时间动态,硝态氮和无机氮具有相同的季节变化趋势,碱解氮与之相反;全氮和有机氮有相同的季节变化趋势,铵态氮与之相反。各氮素形态均以拒盐盐生植物含量相对最高,稀盐盐生植物和泌盐盐生植物相差不大。水平空间动态,就其平均含量而言氮素形态大体排序为:苦豆子、盐豆木、胡杨、多枝柽柳、盐节木、琵琶柴、木本猪毛菜、梭梭、苏打猪毛菜;表层土壤与之相差不大。在盐生植物之间,除铵态氮外其排序均为:拒盐盐生植物、泌盐盐生植物、稀盐盐生植物。垂直剖面动态,土壤氮素含量在整体上呈现随土壤深度增加而减小的趋势。就平均值而言,土壤硝态氮和全氮为逐渐降低趋势,土壤碱解氮和铵态氮则呈不规则“W”型。(2)艾比湖湿地自然保护区干旱生境下盐生植物覆盖的土壤中有效氮素以硝态氮为主。土壤硝态氮含量范围为:1.063mg/kg-27.163mg/kg,平均值为:4.587mg/kg,占全氮量的0.15%-6.99%,无机氮含量的41.27%-96.68%;土壤铵态氮含量范围为:0.328mg/kg-2.722mg/kg,平均值为:1.137mg/kg,占全氮量的0.04%-1.50%,无机氮含量的3.32%-58.73%。土壤硝态氮/铵态氮值的范围为:0.703-29.085。且硝态氮与无机氮的动态变化趋势基本相同,硝态氮与无机氮之间呈极显著正相关关系。(3)土壤理化性质的时间动态变化特征为。时间动态,土壤含水量和电导率,土壤容重和pH值具有相同的季节变化趋势,土壤有机质和容重具有相反的季节变化趋势。水平空间动态,土壤有机质、含水量和容重,土壤pH值和电导率的平均值和表层土壤排序相似,土壤有机质、含水量、容重排序为拒盐盐生植物、泌盐盐生植物、稀盐盐生植物,而pH值、电导率则为泌盐盐生植物、拒盐盐生植物、稀盐盐生植物。垂直剖面动态,土壤有机质含量、pH值、电导率随土壤深度的增加而降低,土壤含水量随土壤深度的增加而升高,土壤容重变化波动较大。(4)土壤硝态氮、全氮、碱解氮、土壤理化性质在同一土壤深度不同样地间存在显著性差异,土壤铵态氮不存在显著性差异。土壤硝态氮、全氮、碱解氮在同一土壤深度不同月份间存在显著差异,土壤含水量、容重和pH值在部分样地存在差异,土壤铵态氮和土壤理化性质则不存在差异。土壤硝态氮、铵态氮、全氮和含水量在同一样地不同土壤深度间不存在显著差异,而碱解氮、有机质、容重、pH值和电导率存在一定程度的显著差异。(5)土壤氮素与土壤理化性质的相互关系。硝态氮与碱解氮和无机氮,碱解氮与全氮、有机氮、无机氮和有机质,全氮与有机氮和有机质,有机氮与有机质之间为高度极显著正相关;硝态氮与全氮、有机氮和有机质,无机氮与全氮、有机氮、有机质和容重,含水量与全氮、有机氮、有机质和电导率之间为高度正相关;容重与硝态氮、碱解氮、全氮、无机氮、有机氮、有机质和含水量之间为高度负相关。而铵态氮与所有氮素形态,pH值与全氮和有机质之间为低度相关,密切程度和关联性最低。(6)在干旱区盐生植物的土壤中,土壤氮素的主要影响因素为土壤有机质、容重和含水量,土壤pH值和含盐量次之。土壤硝态氮含量受碱解氮、无机氮、全氮、有机氮、有机质含量的影响。土壤全氮直接决定碱解氮的含量,有机氮的多寡直接影响土壤氮素的水平和供应能力。(7)在干旱区盐生植物的土壤中,发生淋溶的主要是硝态氮。虽然土壤中的水分含量随土壤深度增加而增加,却未曾发现硝态氮在某层土壤中出现明显的累积现象,即形成硝态氮淋溶的条件不够充分。研究区样地在采样时间和土壤深度未发现硝态氮的淋溶现象。更多还原

【Abstract】 Xinjiang is the largest, broadest, and most comprehensive province of saline soil distribution in China, also concentrated in the world. The vast saline soil lands not only created the foundation of halophytes biodiversity survival and maintenance but also make the halophyte diversity with clear arid area region characteristics. The Ebinur Lake Wetland Nature Reserve was rich in halophyte diversity, account for 40.2% of Xinjiang halophyte species, and mainly in arid habitats. Recent years, environmental changes caused the land desertification, salinization increasingly serious, and had a serious impact on the globe biodiversity. The halophytes play an irreplaceable role on ecological balance maintain of arid area saline soil, ameliorate and utilize of saline soil, curb desertification, maintain biodiversity and promote virtuous cycle of global ecological. Most of them were high value and development potential resources. Preliminary study on soil nitrogen of halophytes in arid habitats provides basic data for salinization improvement. Through preliminary study of soil nitrogen on the nine different halophytes covered plots. The main conclusions were drawn as follows:(1) The temporal dynamic change characters of soil nitrogen forms. Time dynamic: nitrate nitrogen and inorganic nitrogen have similarly seasonal variation tendency, alkali-hydrolyzable nitrogen was the opposite; total nitrogen and organic nitrogen was similar, ammonium nitrogen opposite. The content was relatively highest on exclude halophytes plots of each soil nitrogen forms; more or less between succulent halophytes and salt secrete halophytes. Horizontal space dynamic: the content of soil nitrogen forms in average was Sophora alopecuroides, Halimodendron halodendron, Populus euphratica, Tamarix ramosissima, Halocnemum strobilaceum, Reaumuria soongorica, Salsola arbuscula, Haloxylon persicum, Salsola soda from high to low in order. The surface soil has the similar tendency. The order was exclude halophytes, salt secrete halophytes, succulent halophytes on halophytes types, except ammonium nitrogen. Vertical profile dynamic: soil nitrogen content decrease with soil depth increased overall, soil ammonium nitrogen and alkali-hydrolyzable nitrogen showed an irregular "W" type in average.(2) Soil nitrate nitrogen was the main form of available nitrogen in research area. The mean soil nitrate nitrogen was 4.587mg/kg, rang from 1.063mg/kg to 27.163mg/kg, accounting for 0.15% to 6.99% of total nitrogen, 41.27% to 96.68% of inorganic nitrogen; the mean soil ammonium nitrogen was 1.137mg/kg, rang from 0.328mg/kg to 2.722mg/kg, accounting for 0.04% to 1.50% of total nitrogen, 3.32% to 58.73% of inorganic nitrogen. The ratio between nitrate and ammonium nitrogen was 0.703 to 29.085. Nitrate and inorganic nitrogen almost has the same dynamic change tendency, and also have a high significant positive correlation.(3) The temporal dynamic change characters of soil physicochemical properties. Time dynamic: It has the same seasonal tendency between soil moisture and electrical conductivity, bulk density and pH value; soil organic matter and bulk density was opposite. Horizontal space dynamic: the similar tendency among soil organic matter, water content and bulk density, soil pH value and soil conductivity in average and surface soil. Soil organic matter, moisture content and bulk density was exclude halophytes, salt secrete halophytes, succulent halophytes from high to low in order. Soil pH value and electrical conductivity was salt secrete halophytes, exclude halophytes, succulent halophytes in order. Vertical profile dynamic: soil organic matter, pH value, electrical conductivity decreased with soil depth increased, while soil moisture increased. Soil bulk density exhibited great seasonal fluctuations.(4) Soil nitrate, total nitrogen, alkali-hydrolyzable nitrogen, soil physicochemical properties have significant differences in same soil layer different plots; soil ammonium showed no difference. Soil nitrate, alkali-hydrolyzable and total nitrogen have notable difference between months; soil water content, bulk density and pH value only exist in some plots; ammonium nitrogen and physicochemical properties do not exist. Soil nitrate, ammonium, total nitrogen and water content have no significant difference in same plots different depth. Soil alkali-hydrolyzable nitrogen, organic matter, bulk density, pH value and electrical conductivity have difference in some degree.(5) Relationship between soil nitrogen and physicochemical properties. It was high significant positive correlation among soil nitrate, alkali-hydrolyzable and inorganic nitrogen; alkali-hydrolyzable nitrogen, total nitrogen, organic nitrogen, inorganic nitrogen and organic matter; total nitrogen, organic nitrogen and organic matter; organic nitrogen and organic matter.There was a highly positive correlation among soil nitrate, total nitrogen, organic nitrogen and organic matter;inorganic nitrogen and total nitrogen;organic nitrogen, organic matter and bulk density; water content,total nitrogen,organic nitrogen,organic matter and electrical conductivity; highly negative correlation among soil bulk density, nitrate nitrogen, alkali hydrolyzable nitrogen, total nitrogen, inorganic nitrogen, organic nitrogen, organic matter and water content.The correlation and associated between ammonium nitrogen and other N forms; soil pH value, total nitrogen, and organic matter was the lowest.(6) Soil nitrogen contents in arid areas of halophytes were mainly influenced by soil organic matter, bulk density and water content; soil pH value, salt content to be second.Soil alkali-hydrolyzable nitrogen, inorganic nitrogen, total nitrogen, organic nitrogen, organic matter content were the main influencing factors of soil nitrate content.Soil alkali-hydrolyzable nitrogen content determined by total nitrogen, soil organic nitrogen affect the amount of soil nitrogen and supply capacity directly.(7) Soil nitrate nitrogen was the main leaching nitrogen forms in arid areas of halophytes. Although the soil moisture content increased with soil depth decreased, soil nitrate haven’t show obvious accumulation phenomenon in any layer.So, the condition of formatting nitrate leaching is not sufficient.It means that the phenomenon of nitrate leaching do not presence in the research area, sampling time and soil depth.更多还原