【作者】 董锡文；

【导师】 汪景宽；

【作者基本信息】 沈阳农业大学 ， 土壤学， 2010， 博士

【摘要】 本文以土壤养分和土壤线虫为研究对象,在科尔沁沙地25年固定沙丘上从不同坡位、不同土壤深度和灌丛的影响三方面开展土壤养分和土壤线虫群落时空分布格局研究。目的是探明植被恢复对土壤养分和土壤线虫群落分布格局产生的影响,利用线虫群落指示沙丘生态系统土壤的恢复机理。试验结果表明：(1)随着固沙植物的栽培,沙丘土壤养分NO3--N、NH4+-N和全N的含量随着土层深度的增加而表现出降低趋势,0-5cm土层含量显著高于其余各土层。N03--N和NH4+-N的富集能够降低土壤pH值,并提高土壤EC值,对沙土改良具有重要意义。(2)小叶锦鸡儿的栽植影响了土壤交换性K、Na、Ca和Mg的含量分布,并受坡位的影响较大；随着土层的加深,各交换性盐分含量均表现降低的趋势：灌丛对于交换性Na、Ca和Mg的富集效果显著,对交换性K的效果不显著。(3)TOC、全N和全P的含量随着土层加深而减少,并且迎风坡的TOC、全N和全P含量高于顶坡和背风坡；灌丛下土壤TOC和全K的含量明显高于丛间土壤；灌丛下C/N的变化大于丛间。(4)土壤微生物生物量碳在固定沙丘的不同坡位、不同深度均存在明显差异,表层土壤含量最高,随着土层加深,土壤微生物生物量碳有所减少；植物栽植有利于土壤微生物生物量的积累。(5)在春季,迎风坡和坡顶土壤线虫的分布由上至下随着土层的加深数目减少；在夏季,各坡位0-5cm土层线虫数量较少,5-10cm较多,下层依次减少。不同坡位间土壤线虫数没有明显差异。食细菌线虫为科尔沁沙地固定沙丘土壤线虫的优势类群。优势属为丽突属(Acrobeles)和拟丽突属(Acrobeloides),其次是鹿角唇属(Cervidellus)和威尔斯属(Wilsonema)。(6)多因素方差分析结果显示,在春季,土壤线虫各指标受坡位影响最大,其次是土深和灌丛；在夏季,土壤线虫各指标受土壤深度影响最大,其次是坡位和灌丛；坡位,灌丛和土深三者交互作用对TNEM,BF和FF影响显著。季节的变化对土壤线虫的TNEM, OP,TD,EI,BI, BF,λ和H’影响显著。(7)除土壤中全钾的含量与土壤呼吸和土壤微生物碳无相关性外,其他各种养分元素含量的增加对土壤呼吸和微生物碳含量均有显著的促进作用,提高了微生物的繁殖能力和活力；土壤微生物的增加为土壤肥力的提升起到了积极的促进作用。(8)土壤养分物质的提升对土壤线虫的总数、食细菌线虫数、食真菌线虫数和均匀度具有重要影响,主要受土壤有机碳、土壤氮素、交换性钾和交换性钠的影响。土壤呼吸与微生物碳量对线虫的影响春季大于夏季。更多还原

【Abstract】 This study objective is to explore effects of plant on spatial distribution of soil nutrients and soil nematode community and to use nematode group to indice recovery mechanism of ecological system on sand dune. Soil nutrients and soil nematode community were researched in different slopes, different depths and shrub influences on Horqin sand land which were planted vegetation for fixing sand dune 25 years ago. The results showed that:(1) Contents of NO3--N, NH4+-N and total N descreased with soil depth for fixing sand vegetation were planted on sand dune. Contents of soil nutrients at depth of 0～5cm were significantly higher than that in other soil layers. The enrichment of NO3--N and NH4+-N decreased pH value and increased EC value, and had an important significance.(2) Exchangeable K, Na, Ca and Mg were influenced by planted Caragana microphylla, especially at different slopes. Every kind of exchangeable salt decreased with soil depth. Shrubs took significantly effects on enrichment of exchangeable Na, Ca and Mg, but no significance on exchangeable K.(3) Contents of TOC, total N and total P decreased with soil depth, and they were higher at WS than at TS and LS. Contents of TOC and total K are significantly higher at US than at BS. Changing range of C/N at US is larger than that at BS.(4) Microbial biomass carbon showed the significantly difference at different slopes and depths of stable sand dune, and the highest content of it was at surface layer. Microbial biomass carbon decreased with soil depth. Planting enhanced the accumulation of microbial biomass carbon.(5) Soil nematode individuals decreased with soil depth at WS and TS in spring. But numbers of nematode were the most at depth of 5～10cm on three slopes in summer, and showed no significance among slopes. Bacterivoirs trophic group is the dominance in Horqin stable sand dune. Dominant genera are Acrobeles, Acrobeloides, Cervidellus and Wilsonema.(6) Multi-factor ANOVA analyisis showed that the most important factor affecting nematode indices is slope in spring. Following that is soil depth and shrub, respectively. In summer, the most important factor is soil depth, and slope and shrub followed. Intereaction from slope, shrub and depth on TNEM, BF and FF are significance. Different seasons affect TNEM, OP, TD, EI, BI, BF,λand H’significantly. (7) Every testing nutrient took a significant effect on soil respiration and microbial biomass carbon except total K, and enhanced the ability of reproduce and activity. Adding number of microbe was benefit to soil fertility greatly.(8) Enrichment of soil nutrients affects the number of SNEM, BF, FF and the J’significantly. The main influence factors were TOC, TN, exchangeable K and Na. Effects of soil spiration and microbial biomass carbon on nematode community were more significant in spring than that in summer.更多还原