塔里木沙漠公路防护林土壤微生物生物量与土壤环境因子的关系

为探讨极端干旱区风沙土土壤微生物与土壤环境因子的作用规律,采用相关分析法研究了塔里木沙漠公路防护林地土壤微生物生物量与理化因子和酶活性的关系.结果表明:土壤容重和粒径减小(R0.85)时,防护林地中土壤微生物数量和生物量有增大趋势,由容重与微生物量的相关性主导;土壤养分含量与土壤微生物数量和生物量呈正相关,主要由速效养分和放线菌、微生物生物量C、P的相关性所致;土壤酶活性与土壤微生物数量和生物量的相关性差异较大,R在0.51～0.91,主要取决于蔗糖酶、磷酸酶与放线菌、微生物量C的相关;土壤盐分增加不利于土壤微生物生物量的积累(R0.63).实践中应为干旱区林地土壤微生物营造良好的土体,促进土壤物质循环

塔里木沙漠公路防护林生态工程的综合生态环境效应

为了探讨重大工程的生态环境效应,从风沙环境、土壤环境、小气候、生物多样性和地下水环境5个方面对塔里木沙漠公路防护林工程的综合生态环境效应进行了研究.结果表明:(1)防护林改变了近地表风沙运动过程,防沙体系内风速、输沙率降低幅度分别达64%~80%和87.45%~99.02%,风沙流结构、沙物质粒度、地表蚀积状况也发生了明显变化;(2)与自然流沙地相比,防护林土壤容重减小,全盐含量、总孔隙度和含水量增大,土壤肥力质量明显提高,其变化基本呈现"先快后慢"的规律;(3)防护林对于小环境改善作用明显,距地面6m范围内,林地不同高度的空气温度普遍低于自然流沙地,而空气湿度则高于自然流沙地,林地土壤温度也低于自然流沙地;(4)随着防护林内生境的变化,土壤微生物种类显著增加,但不同种类微生物的种群分布并不均匀;(5)目前防护林灌溉抽水对地下水位、地下水矿化度的影响不大,水位在厘米级范围波动,矿化度的变化幅度在±1g·L-1左右,且没有明显的变化趋势

Study on the soil microbial characteristics and its relationship with soil fertility of Tarim desert highway shelter-forestland

本文以塔里木沙漠公路防护林地土壤为研究材料，综合运用传统培养计数、生物量和酶活性测定、磷脂脂肪酸甲酯法和PCR-DGGE及DNA序列比对几种土壤微生物生态学研究方法，并结合统计分析方法，揭示了防护林建设后土壤微生物的变化、不同立地条件下土壤微生物的差异、滴灌水矿化度对土壤微生物的效应和土壤微生物因子与土壤理化因子的关系及在土壤肥力质量中的作用，为塔里木沙漠公路防护林生态工程的科学管理提供理论支持。本研究所获得的主要结论如下： 1） 土壤微生物数量、生物量和酶活性随防护林定植年限的增长有增大趋势，即塔里木沙漠公路防护林的建设促进了土壤微生物的发育，土壤微生物活性增强。 2） 塔里木沙漠公路防护林地土壤微生物数量、生物量和酶活性在不同立地条件下存在差异，沙垄基部出现最大值；滴灌水矿化度不同的防护林地土壤微生物微生物数量、生物量和酶活性大小亦有所不同，高矿化度滴灌水不利于土壤微生物生存，体现了塔里木沙漠公路防护林地土壤微生物的空间差异。 3）不同定植年限、立地条件和矿化度滴灌水下林地土壤微生物脂肪酸的构成和种类存在差异。林龄越大，微生物脂肪酸种类越丰富；几个立地条件中沙垄基部微生物脂肪酸种类最多；滴灌水矿化度低时微生物脂肪酸出现较多种类，与土壤微生物数量、生物量和酶活性在不同条件下的变化规律一致。同时，不同的磷脂脂肪酸含量大小与特定的土壤微生物量密切相关，具有很好的生物标记作用。 4） 不同定植年限、立地条件和矿化度滴灌水下土壤细菌DNA片段的多样性指数存在明显差异，而真菌的多样性变化只在不同滴灌水矿化度水平下明显，即土壤细菌的遗传多样性受土壤环境条件影响较大。通过DNA序列的测定与比对，发现塔里木沙漠公路防护林地土壤细菌和真菌均存在优势类群，但细菌出现的类型要明显多于真菌，在不同土壤中存在一定差异，有一定的多样性。 5） 塔里木沙漠公路防护林地土壤微生物量大小与土壤环境条件关系密切。土壤含水量和孔隙度增大、容重和粒径减小、养分含量提高可使微生物数量和生物量明显增大，而土壤盐分含量的增大会使土壤微生物数量和生物量减小。 6） 土壤微生物量对沙漠公路防护林土壤肥力质量的贡献比较突出，尤其是土壤微生物生物量，作为活的土壤有机质部分，对防护林土壤肥力的贡献大于土壤微生物数量。In this thesis, selected the soil from Tarim desert highway shelter-forestland as study material, comprehensively applied several methods such as conventional colony counting, determining microbial biomass and enzyme activity, phospholipid fatty acid esterification, PCR-DGGE and blasting DNA sequence for studying soil microbial ecology, combined with statistical analysis methods, the laws of soil microbial variation after Tarim desert highway shelter-forest constructed, soil microbial differences between different site conditions, the effect of mineralization of drip irrigation water on soil microbe, the correlations of soil microbial factors and physicochemical factors, and the contribution of soil microbe to soil fertility quality, which should provide theoretical support for scientific managing the project of ecological shelterbelt construction along the Tarim desert highway. The main results concluded from these studies are: 1) With increase of plantation age of the shelter-forest, soil microbial quantity, biomass and enzymatic activity increased, this means constructing Tarim desert highway shelter-forest could promote soil microbe development, and soil biological activity enhanced. 2) There were differences for soil microbial quantity, biomass and enzymatic activity of Tarim desert highway forest between different site conditions, and the maximum one was the soil of base of sand dune. The mineralization of dip-irrigation water also made soil microbial quantity, biomass and enzymatic activity of the forest land different, and the higher mineralization of dip-irrigation water went against soil microbe survival. These two results reveal the spatial difference of soil microbe of Tarim desert highway shelter-forestland. 3) The soil microbial fatty acid compositions of the forestlands were different between different planting ages, different site conditions and different mineralization of drip-irrigation water. Similar to soil microbial quantity, biomass and enzymatic activity, the greater of the forest age, the more species of soil microbial fatty acids; among several site conditions, the base of sand dune had the richest microbial fatty acid; soil microbial fatty acid richer when the forestland drip-irrigated with the lower mineralization water. Meanwhile, being a good biological marker, the content of soil microbial phospholipid fatty acid had close correlation with soil microbial factors. 4) The diversities of soil bacterial DNA segment were obviously different between the forestlands of different planting ages, different site conditions and different mineralization of drip-irrigation water, but the diversities of soil fungus DNA segment were only remarkably different between the forestlands of different mineralization of drip-irrigation water, which indicates that the soil microbial genetic diversity of Tarim desert highway forestland tended to influence by soil environmental conditions. By sequencing and blasting soil microbial DNA sequences, the soil bacterial and fungus dominant species were founded in Tarim desert highway shelter forestlands, and the bacterial species had more than fungus and appeared obvious diversity. 5) There were close relations between soil microbial factors and physiochemical factors of Tarim desert highway shelter forestlands. The measures of increasing soil moisture content and porosity, decreasing soil bulk density and particle size, enhancing soil nutrient content could make soil microbial quantity and biomass increased, but the higher soil salt content may cause soil microbial quantity and biomass decreased. 6) Soil microbial factor had greater contribution to soil fertility quality of Tarim desert highway shelter forestlands, especially for soil microbial biomass, as soil active organic matter, had more contribution to the forestland soil fertility than soil microbial quantity

Relationship between Species Diversity of Herbaceous Plants in the Shelterbelt and Environment Factors

沿塔里木沙漠公路防护林自北向南设置了10个调查样地, 对草本植物的多度、盖度、丰富度进行调查, 记录和测定各样地内地下水的埋深、电导率、矿化度, 土壤电导率、灌木平均冠幅、灌木层郁闭度等环境因子。分析各样地物种多样性、样地间相似性的差异, 以及草本植物层片物种多样性与环境因子的关系。结果表明: 塔里木沙漠公路防护林下草本植物层片物种多样性与地下水(埋深、水质)、表层土壤电导率之间存在密切关系, annon？？W ie？？ner指数与地下水埋深、地下水电导率、0~ 10 cm 土壤电导率的相关系数分别为0. 72, 0. 63和0. 69, S impson多样性指数与地下水埋深、地下水电导率、0~ 10 cm 土壤电导率的相关系数分别为0. 65, 0. 61和0. 69

灌水量对大麦籽粒蛋白质及其组分含量的影响

研究在大田条件下灌水量对大麦籽粒蛋白质及其组分含量的影响。结果表明:不同灌水量对大麦籽粒蛋白质性状的效应不明显;品种与灌水量的互作对大麦籽粒醇溶蛋白的作用达到显著水平;不同品种间在蛋白质及其各组分含量上均有不同程度的差异。说明大麦籽粒蛋白质性状的水分生理不敏感,对水分条件的适应性较强

流动沙漠腹地咸水滴灌林地土壤微生物的种群特征

土壤微生物种群结构和多样性研究是了解土壤物质和能量状况的重要途径之一.本文选择磷脂脂肪酸甲酯法和培养计数法,对塔里木沙漠公路防护林地土壤微生物种群特征作了分析,旨在为沙漠公路防护林地的稳定性建设提供理论支持.结果表明,塔里木沙漠公路防护林地建设后土壤微生物数量明显增加,防护林定植年限越长,土壤微生物数量越大,且细菌是优势类群,数量远大于放线菌和真菌.防护林地的建设促进了土壤微生物脂肪酸多样性的提高,脂肪酸种类显著增加,但土层间无明显差异.C14:0、C15:0、C16:0、C17:0、C18:1ω9、C18:0、C18:2ω6和C21:0是林地土壤微生物脂肪酸的优势种,经主成分分析和回归分析后得出C14:0、C16:0、C18:0可有效指示土壤微生物总数量;C15:0、C17:0可用来标记土壤细菌和放线菌;而C18:1ω9和C18:2ω6与土壤真菌密切相关.磷脂脂肪酸甲酯法研究结果能够较好地反映塔里木沙漠公路防护林地土壤微生物的种群结构变化.图2表4参1

塔里木沙漠公路防护林区土壤微生物的立地条件效应

通过分析来源于塔克拉玛干沙漠腹地防护林地的土壤样品,揭示了不同立地条件下防护林土壤微生物的差异及对土壤环境因子的响应规律,主要结论如下:(1)不同立地条件下土壤微生物活性差异极显著,呈现沙垄基部>沙垄中部>沙垄顶部>板结平沙地>流沙地的规律,而土壤深度间微生物数量表现为10～20cm>20～35cm>0～10cm,差异不明显。(2)三种微生物对环境因子的响应有所差异,细菌与土壤总孔隙度、含水量有显著正相关关系,与全K含量显著负相关;放线菌与全P、全K和全盐含量明显负相关,与全N正相关;真菌与全K、全盐含量负相关,与有机质含量和孔隙度大小正相关。(3)土壤不同深度范围内土壤因子对微生物活性的影响程度不同,0～10cm土层主要取决于有机质和N素含量;而土壤盐分状况和孔隙结构对10～20cm微生物较为重要;20～35cm土层中微生物需要满足一定养分供应和土壤结构。因此,土壤微生物对不同立地条件下土壤环境条件响应不同,微生物种群数量表现出一定差异,最终可能影响到微生物在土壤养分转化和促进土壤发育中的作用