复合胁迫和食细菌线虫对土壤生态功能稳定性的影响

发布时间：2018-04-03 22:24

本文选题：线虫分离　切入点：复合胁迫　出处：《南京农业大学》2015年硕士论文

【摘要】：土壤生态功能的稳定性关系到人类的可持续发展,因而维持和提高土壤生态功能稳定性一直是土壤生态学领域的一个中心问题。影响土壤生态功能稳定性主要有生物因素和非生物因素两大类。近年来,关于非生物因素对土壤生态功能稳定性影响的研究一直在持续,但是多集中在单一胁迫上,很少有人研究复合胁迫对土壤生态功能稳定性的影响。由于土壤生态系统多暴露于多种胁迫之下,所以很有必要对复合胁迫下土壤生态系统功能的变化进行深入的探讨。作为土壤中数量最大及多样性最高的动物类群之一,土壤线虫不仅在维持土壤生态系统功能中起着不可替代的作用,而且能够反映土壤环境的微小变化。因此,线虫的群落结构可以用于指示土壤生态功能稳定性的变化。本研究设置了几个胁迫因素(铜、干燥、加热和除草剂),通过测定胁迫下有机物料(小麦叶粉和水稻秸秆)的分解程度和土壤线虫群落结构的改变来反映土壤生态功能的稳定性变化。首先探讨了红壤用量对线虫分离效果的影响,以确定分离线虫的最佳条件;其次研究单一胁迫(干燥、加热和除草剂)及复合胁迫(干燥+加热、干燥+加热+除草剂)在三种不同的农业管理措施(常规淹水、裸地旱作和秸秆覆盖旱作)下对对土壤生态功能稳定性的影响;最后,采用原位富集线虫的方法,设置三种处理(大量线虫、含有极少量线虫、含有极少量线虫但回接微生物群落),研究食细菌线虫对铜或加热胁迫下土壤生态功能稳定性的影响。研究结果表明:对质地较为粘重的红壤土而言,建议采用150g且土壤厚度小于1.00cm的样品量来分离线虫;三种农业管理措施下,施加胁迫对土壤微生物及线虫活性、土壤养分含量及土壤生态功能稳定性的影响差异并不显著,且对土壤或生物因子变化的响应近乎一致;复合胁迫较单一胁迫带来的危害更大,尤其表现在对土壤线虫数量的影响上;无论是在持续性的Cu胁迫还是在瞬间的热胁迫下,添加大量线虫的土壤中,其土壤呼吸值和土壤恢复力均显著高于其他两种添加少量线虫的土壤.说明食细菌线虫可以提高土壤的恢复力。综上所述,本研究进一步明确了生物因素和非生物因素对土壤生态功能稳定性的影响,即胁迫环境对有机物料的分解程度及土壤线虫群落结构的影响。研究表明,复合胁迫较单一胁迫对土壤生态功能稳定性的破坏程度最高;土壤线虫对土壤生态功能稳定性有较好的指示作用;食细菌线虫添加的数量越多对提高土壤的恢复能力更有帮助。
[Abstract]:The stability of soil ecological function is related to the sustainable development of human beings. Therefore, maintaining and improving the stability of soil ecological function is always a central problem in the field of soil ecology.The stability of soil ecological function is mainly affected by biological factors and abiotic factors.In recent years, the study on the influence of abiotic factors on soil ecological function stability has been continuing, but most of them focus on single stress, and few people study the effect of compound stress on soil ecological function stability.Because soil ecosystems are exposed to multiple stresses, it is necessary to study the changes of soil ecosystem functions under complex stress.As one of the largest and most diverse animal groups in soil, soil nematode not only plays an irreplaceable role in maintaining the function of soil ecosystem, but also can reflect the small changes of soil environment.Therefore, the community structure of nematodes can be used to indicate the change of soil ecological function stability.In this study, several stress factors (copper, dryness,The stability of soil ecological function was reflected by the decomposition degree of organic matter (wheat leaf powder and rice straw) and the change of soil nematode community structure under stress by heating and herbicide.The effects of the amount of red soil on the isolation of nematodes were studied in order to determine the optimum conditions for the isolation of nematodes, and then the single stress (drying, heating and herbicide) and the compound stress (drying heating) were studied.Effects of dry heating herbicide on soil ecological function stability under three different agricultural management measures (conventional flooding, dry field cultivation and straw mulching). Finally, the method of in situ enrichment of nematodes was used.Three treatments (a large number of nematodes containing a very small amount of nematodes and a very small amount of nematodes but a return microbial community) were set up to study the effects of bacterial nematode feeding on the ecological stability of soil under copper or heat stress.The results showed that, for red loam soil with relatively sticky texture, 150g sample with soil thickness less than 1.00cm should be used to isolate nematode, and under three agricultural management measures, soil microorganism and nematode activity should be subjected to stress.The effect of soil nutrient content and soil ecological function stability was not significant, and the response to soil or biological factors was almost the same, and the harm of compound stress was greater than that of single stress.In particular, the effect on the number of soil nematodes, whether under persistent Cu stress or transient heat stress, was found in the soil where a large number of nematodes were added to the soil.The soil respiration value and soil resilience were significantly higher than those of the other two kinds of soil supplemented with a small amount of nematodes.The results showed that bacterial nematodes could improve the resilience of soil.To sum up, the effects of biological and abiotic factors on the ecological functional stability of soil, namely, the degree of decomposition of organic materials and the structure of soil nematode community, were further clarified in this study.The results showed that the damage degree of soil ecological function stability was the highest under complex stress, and the soil nematode had better indication effect on soil ecological function stability.The more the addition of bacterial nematode to the soil, the more helpful it is to improve the resilience of soil.
【学位授予单位】：南京农业大学
【学位级别】：硕士
【学位授予年份】：2015
【分类号】：S154.1

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