| 摘要: |
| 土壤微生物是养分转化和能量流动的重要驱动力。林地复垦为农田可能对土壤特性和微生物群落产生深远影响。然而，关于土壤微生物群落对旱地农业生态系统土壤复垦的反应知之甚少。因此，有必要对土地利用转变驱动土壤微生物群落的变化进行研究，以促进复垦农田的养分循环。基于宏基因组技术，对黄土高原上进行复垦后的新造耕地与两种传统农田（坡耕地和淤地坝）的微生物组成和功能进行评价，并探讨优势菌属和土壤性质对养分循环功能的影响。结果表明：变形菌、放线菌和酸杆菌在三种农田中普遍存在。与传统农田相比，新造耕地增加了放线菌和诺卡氏菌的相对丰度，以及与氨基酸代谢和碳水化合物代谢相关的基因。新造耕地中碳氮循环功能基因的相对丰度高于传统农田。Pearson相关性表明养分循环功能基因的相对丰度与三种农田的优势菌属呈正相关，但对土壤性质的响应不同。除pH值外，土壤理化因子与大部分功能基因呈负相关。微生物组成和功能的差异可能与土壤养分有效性和农业干扰程度有关。微生物通常具有功能冗余以应对不断变化的环境。长期的农业活动导致传统农田养分循环功能丧失。一些可持续的农业管理方法可以帮助调节微生物参与的养分循环。因此，有必要应用可持续农业方式来调节微生物驱动的养分循环。这些见解对于干旱地区农业可持续发展和土地管理具有重要意义。 |
| 关键词: 宏基因组学 微生物功能 农田 养分循环 黄土高原 |
| DOI：10.7515/JEE222084 |
| CSTR：32259.14.JEE222084 |
| 分类号: |
| 基金项目:国家重点研发计划（2017YFD0800500） |
| 英文基金项目:National Key Research and Development Program of China (2017YFD0800500) |
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| Structure and functional heterogeneity of soil microbial communities in different farmland types on the Loess Plateau |
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XU Chen, SU Cuicui, CHEN Yiping, MA Jifu, WU Junhua, JIANG Yao
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1. State Key Laboratory of Loess and Quaternary Geology, Institute of Earth Environment, Chinese Academy of Sciences, Xi’an 710061, China
2. University of Chinese Academy of Sciences, Beijing 100049, China
3. Xi’an Institute for Innovative Earth Environment Research, Xi’an 710061, China
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| Abstract: |
| Background, aim, and scope Soil microbes are important drivers of nutrient transformation and energy flow. Reclaiming forest land for agricultural use may have profound effects on soil properties and microbial communities. However, the response of soil microbial communities to soil reclamation in the dryland agroecosystem is less understood. Therefore, it is necessary to investigate the changes of soil microbial communities driven by land use conversion to promote nutrient cycling in reclaimed farmland. Materials and methods Based on the metagenomic technique, we evaluated the microbial composition and function of the newly created farmland (NF) after reclamation with two types of traditional farmland (slope farmland (SF), check-dam farmland (CF)) on the Loess Plateau, and explored the response of nutrient cycling function to dominant genera and soil properties. Results The results showed that Proteobacteria, Actinobacteria, and Acidobacteria were prevalent in the three types of farmlands. Compared with SF and CF, NF increased the relative abundance of Actinobacteria and Nocardioides, as well as genes related to amino acid metabolism and carbohydrate metabolism. The relative abundance of functional genes related to carbon and nitrogen cycling in the NF was higher than that in the traditional farmland (SF and CF). The relative abundance of nutrient cycling functional genes was positively correlated with dominant genera in the three types of farmlands. Except for pH, soil physicochemical factors were negatively correlated with genes related to amino acid metabolism and carbon cycle. Discussion Previous studies have shown that the nutrient conditions of the soil may intensify the competition between the eutrophic and oligotrophic microbial populations. After long-term cultivation and fertilization, the soil properties of traditional farmland were significantly different from those of NF, leading to the differentiation of dominant microbial groups. Microbes usually have functional redundancy to cope with changing environments. Soil microbes in traditional farmland may contain more genes related to replication and repair, cell growth and death, and environmental adaptation in response to disturbances caused by agricultural practices. On the contrary, the NF was less disturbed by agricultural activities, and the soil properties were more similar to forest land, so the carbon and nitrogen cycle function genes were more abundant. The nutrient cycling function was affected by the abundance of microbial dominant groups and soil properties, which may be related to the availability of soil nutrients and agricultural disturbance in different farmlands. Aspects of soil microbial-driven nutrient cycling in agriculture could be regulated in sustainable method. Conclusions The change from forest land to farmland kept more carbon and nitrogen cycling function in the newly created farmland, while long-term agricultural activities have drastically changed the functional structure of traditional farmland, resulting in the nutrient cycling function more concentrated to meet the needs of crop growth. Recommendations and perspectives Hence, it is necessary to apply sustainable agricultural method to regulate microbial-driven nutrient cycling. The insights are meaningful for sustainable agricultural development and land management in arid areas. |
| Key words: metagenomics microbial function farmland nutrient cycling Loess Plateau |
