【作者】 于江；

【导师】 朱昌雄；

【作者基本信息】 中国农业科学院 ， 农业微生物学， 2009， 博士

【摘要】 新疆荒漠化土地总面积达7.96×10⁵km²,约占新疆国土面积的47.7%,土地荒漠化已逐步成为新疆土地退化的重要表现之一,亟待治理。新疆是我国甘草的重要产区,提高甘草产量与改善甘草产地环境防止土壤沙退化具有重要的社会、经济和环境效益。首先在温室条件下,以沙退化土壤为研究对象,通过正交试验和生物腐植酸（BHS）施用量梯度试验对土壤有机质含量、土壤微生物数量以及紫花苜蓿生物量等指标进行了考察,验证了生物腐植酸的修复效果,进一步通过新疆田间小区试验,考察了施入生物腐植酸后连续三年甘草生物量的变化,较全面系统地研究了不同施用量生物腐植酸对甘草种植区产地土壤质量的改良效果,分析了施用生物腐植酸后第90d、110d、130d、150d和190d时土壤各指标的变化规律和指标间的相互关系,验证了生物腐植酸的增产作用以及对产地环境的改善作用。通过主成分分析与聚类分析对作用效果进行了系统性评价,初步建立了适合于新疆甘草产地土壤质量的综合指标评价体系。全文主要得出了以下结论:1.室内生物腐植酸修复效果验证试验施入生物腐植酸后,沙退化土壤质量得到了很大改善,土壤有机质含量、土壤微生物数量和紫花苜蓿生物量得到了较快而显著地提高。初步明确了腐植酸与微生物的相互关系及对修复的贡献:微生物单独作用时修复效果不明显,腐植酸单独作用时具有一定的修复效果,微生物显著提高了腐植酸的作用效果,即生物腐植酸作为整体修复效果最好。2.新疆甘草种植区实地修复试验（1）从甘草植株高度、单株地上鲜重和产量三个方面考察了不同施用量生物腐植酸对三年内甘草生长状况的影响。结果表明,生物腐植酸对甘草产量的影响明显大于对植株高度和单株地上鲜重的影响。中量(450kg·hm^-2)生物腐植酸对甘草植株高度、单株地上鲜重和产量（干重）的作用效果最好。以2009年为例,各指标分别达到80.80cm、137.5g和18412.95kg·hm^-2,分别比对照提高了8.2%、6.9%和29.1%,差异达显著或极显著水平。（2）与对照相比,施用生物腐植酸能够显著促进土壤质地的改善,作用效果随施用量的增加而增强,土壤粗砂粒含量显著下降,粘粉粒和粘粒含量显著提高;90d-150d的过程中,土壤pH变动不大,150d-190d的过程中有所下降,但保持弱碱性;土壤全氮和有机碳含量显著提高,最佳施用量为450kg·hm^-2,190d时,分别由对照的0.758g·kg-1和7.55 g·kg-1增加至0.922g·kg-1和8.75 g·kg-1,分别增加了21.6%和15.9%;土壤全磷含量有增加的趋势,全钾含量则有下降的趋势。（3）土壤可提取腐殖质碳（EH-C）、富里酸碳（FA-C）、胡敏酸碳（HA-C）含量显著提高,最佳施用量为450 kg·hm^-2。190d时,EH-C、FA-C和HA-C含量分别达到4.15g·kg-1、2.16g·kg-1和1.99g·kg-1,分别比对照提高了21.0%、17.4%和20.1%。（4）土壤脲酶、碱性磷酸酶、过氧化氢酶活性显著提高,最佳施用量为450 kg·hm^-2。190d时,土壤脲酶、碱性磷酸酶、过氧化氢酶活性分别达到187.12mg·kg-1·3h-1、26.33mg·kg-1·h-1和3.62mL 0.1 mol·L-1 KMnO4·g-1·20min-1,分别比对照提高了57.6%、20.3%和11.9%。（5）土壤细菌和放线菌数量、可培养微生物总数、氨化细菌和自生固氮菌数量,微生物生物量碳含量以及微生物商显著提高,最佳施用量为450kg·hm^-2。对130d时该施用量下平板分离的细菌菌种进行16SrDNA分子鉴定的结果表明,绝大多数为芽孢杆菌。（6）相关性分析表明,各指标之间的相关性以施用生物腐植酸后的第190d时最好。综合来看,土壤粘粉粒含量（<0.005mm）、粘粒含量（<0.002mm）、土壤全氮、碱解氮、速效磷、速效钾、有机碳、可提取腐殖质碳、富里酸碳、胡敏酸碳、土壤酶活性、除真菌外的土壤微生物学指标之间呈极显著或显著正相关。甘草产量与微生物生物量碳和微生物商呈显著正相关。（7）分别采用土壤机械组成、化学指标、土壤酶活性指标、土壤微生物学指标的原始指标、主成分指标和主成分综合评分指标进行聚类分析,结果表明:采用各种指标均可对目标土壤进行有效的划分。按不同处理的效果进行排序,结果如下:450kg·hm^-2>750kg·hm^-2> 600kg·hm^-2> 300kg·hm^-2>150kg·hm^-2>对照。初步建立了新疆甘草种植区土壤质量评价体系,具体评价指标为植物生物量、土壤机械组成、土壤全氮、碱解氮、速效磷、速效钾、有机碳、碳氮比、可提取腐殖质碳、富里酸碳、胡敏酸碳、脲酶活性、碱性磷酸酶活性、过氧化氢酶活性、细菌、放线菌、真菌的数量、氨氧化菌和自生固氮菌的数量、可培养微生物总数、微生物生物量碳、微生物商等。更多还原

【Abstract】 The total area of Xinjiang desertified land is 7.96×10⁵km², which takes up 47.7% of Xinjiang total area. Desertification has become the main presentation of Xinjiang soil degradation, which needs immediate restoration. Furthermore, Xinjiang is one of the most important Glycyrrhiza uralensis production areas in China. Improving the yield and modifying the production environment to prevent soil degradation and desertification have great social, economical and environmental profits. The in-house restoration effect verification test of bio-active humic substances （BHS） was first conducted, which verified the marvelous restoration effect of BHS on the desertification-caused degraded soil and made it relatively clear the relationship between humic acids and microorganisms. The effects of BHS at different rates on the soil quality of Glycyrrhiza uralensis production area were systematically studied through in-situ restoration test in Xinjiang. The dynamic changes of the soil mechanical composition, main nutrients, humus composition, enzymatic activities and microbial indices were analyzed and the restoration effects of BHS were verified. Systematic evaluation of the restoration effect was conducted through principal component and cluster analysis, and the comprehensive evaluation system fitting for evaluating the soil quality of Xinjiang Glycyrrhiza uralensis production area was established. The following conclusions were mainly drawn:1. In-house BHS restoration effect verification testThe quality of the BHS-treated soil has been greatly improved. The content of soil organic matter, the quantity of soil microbes and the biomass of Medicago sativa L. have rapidly and significantly increased. The relationship between humic acid and microbes and their respective contributions to the restoration were analyzed: the restoration effect was not obvious if microbes acted by itself.The humic acid itself played a more important role in restoration and microbes significantly improved the restoration effect of humic acid.The bio-active humic substances, as a whole, had the best restoration effect .2. In-situ restoration test of Xinjiang Glycyrrhiza uralensis production area（1） The height, aboveground fresh weight per plant and yield were examined to evaluate the effect of BHS at different rates on the growth status of Glycyrrhiza uralensis. The results showed that the effects of BHS were significantly different due to their rates. Medium and low rates of BHS contributed more to the increase of plant height and the aboveground fresh weight per plant. The former reached 80.8cm and 79.4cm and increased by 8.2% and 6.3%,respectively,the latter reached 137.5g and 134.7g and increased by 6.9%和4.7%,respectively,while the treatment of high rates of BHS showed little difference compared with the control. The yield reached 18412.95kg·hm^-2·dry weight and 16666.05kg·hm^-2·dry weight with the application of medium and high rates of BHS, respectively, increased by 29.1% and 16.9%,while the yield under the treatment of low rates of BHS was lower than the control with no BHS incorporation.（2）The soil texture was significantly promoted with the application of BHS,compared with the control with no BHS incorporation. The contents of coarse and fine sand decreased sharply with the increasing rates of BHS, while the silt and clay content increased significantly. During the first 150 days after application of BHS, soil pH showed little change and was in the range of 8.53-8.92.From the 150th to 190th day, the soil pH dropped obviously and fluctuated in the range of 7.80-8.19.The pH of the soil treated by BHS was slightly higher than that of the control. The contents of soil total nitrogen and organic carbon were significantly improved with the application of BHS and the best application rate was 450kg·hm^-2, at which the contents at the190th day increased by 21.6%, from 0.758g·kg-1 to 0.922g·kg-1 and 15.9%, from 7.55 g·kg-1 to 8.75 g·kg-1, respectively. There was an increasing trend for total phosphorus content and a descending trend for the total potassium.（3） The contents of extractable humus carbon（EH-C）, fulvic acid carbon（FA-C） and humic acid carbon（HA-C） were greatly improved with the application of BHS, especially at the rate of 450kg·hm^-2,which reached 4.15g·kg-1, 2.16g·kg-1 and 1.99g·kg-1, respectively and increased by 21.0%, 17.4% and 20.1% correspondingly, compared with the control.（4）The soil urease, alkaline phosphatase and catalase activity were significantly improved after application of BHS. The best rate was 450kg·hm^-2 and the soil urease, alkaline phosphatase, catalase activities reached 187.12 mg·kg-1·3h-1, 26.33 mg·kg-1·h-1 and 3.62 mL 0.1mol·L-1KMnO4·g-1·20min-1, respectively and increased by 57.6%, 20.3% and 11.9%, compared with the control.（5） The numbers of soil bacteria, actinomycetes, total cultivatable microbes,ammonia-oxidizing bacteria and azotobacter, microbial biomass carbon content and microbial quotient were significantly improved after application of BHS and basically the application rate 450 kg·hm^-2 was the best, at which the strains separated from the plates at the 130th day were identified based on the 16SrDNA sequences.The results showed that the prevailing bacteria were Bacillus sp and the strains were identified as Bacillus pumilus, Bacillus amyloliquefaciens, Bacillus gibsonii, Bacillus simplex, endogenous Bacillus, Bacillus megaterium, Bacillus subtilis,Georgenia ferrireducens and Kocuria sp.（6） Correlation analysis showed that the indices were best correlated at the 190th day.Generally, the soil clay and silt content （<0.005mm）, clay content （<0.002mm）, total nitrogen, available nitrogen, available phosphorus, available potassium, organic carbon, extractable humus carbon, fulvic acid carbon, humic acid carbon, soil enzyme activity and microbial indices with the exception of fungi presented significant or extremely significant positive correlation, which indicated that the BHS had much influence on soil physical, chemical,biochemical and microbial indicators. There was positive correlation between the yield and other soil indices （except soil fungi）, especially the microbial biomass carbon and microbial quotient,which presented significant positive correlation. The improvement of soil quality was the comprehensive embodiment of various soil characters. Combined with the indices analyzed above and the data of the yield, 450kg·hm^-2 was defined as the best application rate.（7）The original, principal component and principal component comprehensive score of soil physical, chemical, biochemical and microbial indices were used to conduct cluster analysis. The objective soils were well classified according to the restoration effects, which were as follows: 450kg·hm^-2>750 kg·hm^-2> 600 kg·hm^-2>300 kg·hm^-2> 150 kg·hm^-2> control.According to the changes of indices after application of BHS and the result of principal component and cluster analysis, The soil quality evaluation system for Xinjiang Glycyrrhiza uralensis production area was established. The specific indices consist of soil mechanical composition, total nitrogen, available nitrogen, available phosphorus, available potassium, organic carbon, C/N ratio, extractable humus carbon, fulvic acid carbon, humic acid carbon, activities of urease, alkaline phosphatase and catalase, numbers of bacteria, actinomycetes and fungi, numbers of ammonia-oxidizing bacteria and azotobacter, total numbers of cultivatable microorganisms, microbial biomass carbon and microbial quotient.更多还原