川中丘陵区坡耕地土壤侵蚀对土壤微生物特性的影响
文献类型：学位论文
| 作者 | 聂小军 |
| 学位类别 | 博士 |
| 答辩日期 | 2009 |
| 授予单位 | 中国科学院水利部成都山地灾害与环境研究所 |
| 授予地点 | 成都 |
| 导师 | 张建辉 |
| 关键词 | 水蚀 耕作侵蚀 有机碳 微生物量碳 酶活性 坡耕地 |
| 其他题名 | Soil erosion effects on soil microbial properties on sloping cultivated lands in hilly areas of the Sichuan Basin, China |
| 学位专业 | 自然地理学 |
| 中文摘要 | 土壤侵蚀造成的土壤质量退化是全球关注的一个环境问题。目前这方面的研究热点主要集中于土壤侵蚀对土壤理化性质的影响，然而土壤侵蚀对土壤微生物特性的影响还没有引起人们的重视。本研究以川中丘陵区为试验区，选择了有代表性的缓长坡与陡梯坡耕地，通过137Cs示踪、土样采集、土壤理化、微生物特性测定方法探讨了土壤侵蚀对坡耕地土壤微生物特性的影响。主要结论如下： (1)研究区坡耕地土壤总侵蚀速率平均4100 t/km2·yr-1，陡梯坡耕地土壤侵蚀速率及其空间变异均大于缓长坡耕地。耕作侵蚀导致了这两种侵蚀坡耕地顶部严重的土壤损失。水蚀造成的缓长坡耕地中下坡土壤损失也很严重。在这两种侵蚀坡耕地的底部，土壤侵蚀最弱，甚至表现处一定的土壤沉积。缓长坡与陡梯坡耕地土壤再分配格局的不同归因于这两种坡耕地主导侵蚀过程的不同。陡梯坡耕地土壤侵蚀以耕作侵蚀为主，而缓长坡耕地土壤侵蚀以水蚀为主。 (2)土壤侵蚀造成了坡耕地土壤微生物特性空间异质性增大。其中，侵蚀坡耕地土壤MBC(微生物量碳)含量、IA(蔗糖酶活性)、UA(脲酶活性)、MBC/SOC(微生物商.)、IA/MBC、UA/MBC空间变异明显增大。其次，土壤侵蚀造成了坡耕地土壤生物学肥力下降。其中，土壤MBC含量与AL.PA(碱性磷酸酶活性)显著降低。土壤侵蚀导致坡耕地土壤微生物特性间相关性变差，也造成了土壤微生物特性与理化性质相关联系变差。 (3)坡耕地主导侵蚀过程的不同对土壤微生物特性的影响不同。 水蚀对土壤AL.PA的抑制效应导致其在水蚀为主导侵蚀过程的坡耕地上大的空间变异。侵蚀引起的土壤再分配影响土壤微生物特性分布格局。土壤细菌数量、IA在两种侵蚀坡耕地上受土壤再分配的影响都很明显，而AL.PA、AL.PA/MBC、IA/MBC、MBC/SOC在两种侵蚀坡耕地上受土壤再分配的影响不明显。土壤MBC含量、UA、UA/MBC只在水蚀为主导侵蚀过程的坡耕地上受土壤再分配的影响明显。土壤再分配引起的土壤水分储量、SOC、全氮、有效磷及速效钾储量变化是影响水蚀为主导侵蚀过程的坡耕地细菌数量、MBC、UA、IA的主要因素。土壤再分配引起的土层深度、水分储量、SOC、全氮、全磷、全钾、碱解氮储量变化是影响耕作侵蚀为主导侵蚀过程的坡耕地土壤细菌数量、AL.PA、IA的主要因素。 不同侵蚀类型的坡耕地土壤微生物特性的内在相关表现不同。受土壤再分配的制约，水蚀为主导侵蚀过程的坡耕地土壤细菌数量与其它微生物特性相关较强。水蚀对土壤AL.PA的抑制效应导致水蚀为主导侵蚀过程的坡耕地土壤碱性磷酸酶与MBC、脲酶、蔗糖酶没有相关关系。 不同侵蚀类型的坡耕地土壤微生物特性与理化特性的相关关系表现不同。土壤AL.PA只在陡梯坡耕地上与全磷、速效磷含量相关，表明耕作侵蚀为主导过程的坡耕地土壤碱性磷酸酶较好地参与了磷素的循环与转化。土壤IA在缓长坡耕地上与SOC含量极显著正相关，而在陡梯坡耕地上仅与SOC含量弱相关，表明蔗糖酶在水蚀为主导侵蚀过程的坡耕地上参与C素循环与转化的状况好于其在耕作侵蚀为主导侵蚀过程的坡耕地。 (4)土壤侵蚀导致了坡耕地SOC库与MBC库降低及其空间异质性增大。水蚀为主导侵蚀过程的坡耕地上，水蚀的分选性搬运造成SOC库积累效率的降低。耕作侵蚀为主导侵蚀过程的坡耕地上，耕作侵蚀的整体性搬运造成SOC库积累效率升高。坡耕地SOC与MBC储量的坡面分布格局体现了明显的土壤侵蚀特征。水蚀为主导侵蚀过程的坡耕地SOC、MBC储量分布与侵蚀引起的土壤再分配格局一致。耕作侵蚀为主导侵蚀过程的坡耕地上，仅仅SOC储量的空间分布一致于土壤再分配。水蚀为主导侵蚀过程的坡耕地上，土壤IA明显影响SOC与MBC动态，而在耕作侵蚀为主导侵蚀过程的坡耕地上，IA对SOC动态影响明显，但对土壤MBC动态影响不明显。 (5)比值指标MBC/SOC、AL.PA/MBC、UA/MBC、IA/MBC较MBC或酶活性指标能更好地反映侵蚀土壤生物学肥力变化。土壤IA不仅可以反映川中丘陵区坡耕地土壤侵蚀状况与土壤理化特性变化，而且还可以预测侵蚀坡耕地SOC库的动态。土壤细菌数量是川中丘陵区坡耕地土壤侵蚀影响的一个敏感因子。只有在考虑侵蚀类型的前提下，土壤细菌数量才可以作为反映川中丘陵区水蚀与耕作侵蚀分别为主导侵蚀过程的坡耕地土壤侵蚀状况的生物学肥力指标；土壤MBC含量、UA才可以作为反映川中丘陵区水蚀为主导侵蚀过程的坡耕地土壤侵蚀状况的生物学肥力指标。 |
| 英文摘要 | Soil quality degradation by soil erosion is an environmental problem concerned worldwidely. At present, little has been known about the influences of soil erosion on soil microbial properties, while researchers have much attention to the effects of soil erosion on soil physical and chemical properties. In this study, representive sloping cultivated lands in hilly areas of the Sichuan Basin are selected to discuss the impacts of soil erosion on soil microbial properties. 137Cs tracing method is applied, and soil samples for the determination of physical, chemical and microbial properties are collected and measured. The main conclusions are as follows: ⑴ Soil erosion rate of sloping cultivated lands averages 4100 t/km2•yr-1 in the study area. Soil erosion rate and its spatial variation of steep sloping terraces are large as compared to those of gentle-long slopes. Serious soil loss induced by tillage erosion appears in upper slope positions of the two types of cultivated lands. Besides, soil loss caused by water erosion is also serious in low-middle slope positions of gentle-long slopes. On the other hand, insignificant soil loss or significant soil depositon occurs in bottom positions of the two types of cultivated lands. The soil redistribution patterns attribute to the difference in dominant erosion processes on the two types of cultivated lands. Tillage erosion is the dominant erosion process on steep sloping terraces, whereas water erosion is the dominant one on gentle-long slopes. ⑵ Soil erosion increases the spatiall variations of soil microbial properties across sloping cultivated lands. Thereinto, the spatial variations of soil MBC content, IA, UA, MBC/SOC, IA/MBC and UA/MBC obviously increase on eroded sloping cultivated lands. Soil erosion causes a decrease in soil microbial quality. Especially, soil MBC content and AL.PA decline significantly. Moreover, soil erosion weakens the inherent correlations of soil microbial properties on the eroded sloping cultivated lands. Likewise, soil erosion also weakens the correlations of soil microbial properties to physical and chemical properties on the eroded sloping cultivated lands. ⑶ The difference in domaint erosion processes affects soil microbial properties on the eroded sloping cultivated lands. The depressing effect of water erosion on soil AL.PA contributes to large spatial variation of AL.PA on the sloping cultivated lands dominated by water erosion processs. Soil redistribution by erosion impacts on distribution patterns of soil microbial properties. Except for significant effects of soil redistribution on bacteria number and IA and insignificant effects on AL.PA、AL.PA/MBC、IA/MBC and MBC/SOC on the two types of cultivated lands, soil redistribution notably affects MBC content, UA and UA/MBC. The changes in soil water storage, the storages of SOC, total N, available P and available K under soil redistribution are main environmental influence factors to soil bacterial number, MBC, UA and IA on the sloping cultivated lands dominated by water erosion process. The changes in soil depth and the storages of soil water, SOC, total N, P, K and available N under soil redistribution are main environmental influence factors to soil bacterial number, AL.PA and IA on the sloping cultivated lands dominated by tillage erosion process. The inherent correlations between soil microbial properties differ on different erosion types of cultivated lands. Under the effects of soil redistribution, soil bacterial number was related closely to other microbial properties on the sloping cultivated lands dominated by water erosion compared to those dominated by tillage erosion. Due to the depression effect of water erosion on AL.PA, soil alkaline phosphatase related weakly to MBC、urease and invertase on the sloping cultivated lands dominated by water ersion process compared to those dominated by tillage erosion processs. The correlations of soil microbial properties to physical and chemical properties differ on different erosion types of sloping cultivated lands. Correlations of soil AL.PA with total P and available P were found only on the sloping cultivated lands dominated by tillage erosion processs, showing a good involvement in the P cycle and transformation on the sloping cultivated lands. Soil IA was significantly correlated with SOC contents on the sloping cultivated lands dominated by water erosion process, but only weakly correlated with SOC contents on those dominated by tillage erosion process, suggesting a better involvement in C cycle and transformation on the sloping cultivated lands dominated by water erosion process. ⑷ Soil erosion decreases SOC and MBC stocks and increases their spatial variations on the eroded sloping cultivated lands. On the sloping cultivated lands dominated by water erosion process, the selective transport of soil materials during the water erosion process reduces the accumulation efficiency of SOC stocks. Contrarily, on the sloping cultivated lands dominated by tillage erosion process, the entire transport of soil during tillage erosion process increases the accumulation efficiency of SOC stocks. The distribution patterns of SOC and MBC are characterized by obvious soil erosion. The distributions of SOC and MBC storages are consistent with soil redistribution induced by erosion on the sloping cultivated lands dominated by water erosion process, but only SOC distribution accords with soil redistribution on the sloping cultivated lands dominated by tillage erosion processs. Soil IA significantly affects SOC and MBC dynamics on the sloping cultivated lands dominated by water erosion processs, while it only affects SOC dynamics without an influence on MBC dynamics on those dominated by tillage erosion process. ⑸ Compared to either MBC or enzyme activity parameters alone, MBC/SOC and the ratios between soil enzyme activity parameters and microbial biomass can better reflect changes in soil microbial quality in the eroded soils. Soil IA can not only reflect soil erosion status and soil quality changes, but also forecast SOC dynamics on sloping cultivated lands in hilly areas of the Sichuan Basin. Soil bacteria number is proved to be one of sensitive parameters to soil erosion on eroded sloping cultivated lands in hilly areas of the Sichuan Basin. Only considering erosion pattern, soil bacteria number can reflect soil erosion status of the sloping cultivated lands dominated by water erosion and tillage erosion processes, respectively, and soil MBC contents and UA can reflect soil erosion status of the sloping cultivated lands dominated by water erosion process. |
| 学科主题 | 微生物学 ; 土壤学 |
| 语种 | 中文 |
| 公开日期 | 2010-10-13 |
| 分类号 | S15;X17 |
| 源URL | [http://ir.imde.ac.cn/handle/131551/2153]  |
| 专题 | 成都山地灾害与环境研究所_成都山地所知识仓储（2009年以前） |
| 推荐引用方式 GB/T 7714 | 聂小军. 川中丘陵区坡耕地土壤侵蚀对土壤微生物特性的影响[D]. 成都. 中国科学院水利部成都山地灾害与环境研究所. 2009. |
入库方式： OAI收割
来源：成都山地灾害与环境研究所
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