宁夏引黄灌区稻蟹共作对土壤微生物群落结构及理化因子的影响

Rice-crab co-culture influences microbial community structure and physicochemical indicators of soil in the Yellow River irrigation area of Ningxia

摘要:

【目的】 探究宁夏引黄灌区稻蟹共作对土壤理化指标和微生物群落结构的影响，旨在为西北引黄灌溉地区推广稻蟹养殖提供一定的理论依据。【方法】 基于土壤理化指标测定和16S rRNA基因扩增子高通量测序技术，对单一水稻种植(CK)与环沟引入蟹形成的稻蟹共作(EG)土壤理化指标和微生物群落结构进行分析。【结果】 在理化指标上，4−8月EG显著提高了土壤pH、总氮和有机质含量，降低全盐含量。总氮、有效磷和有机质含量在6月和7月EG明显高于CK。在微生物群落结构特征上：EG可以明显改变土壤中细菌群落的物种多样性与丰度，其中4月和8月可以提高细菌群落的物种多样性与丰度。与CK相比，EG在4−8月门水平相对丰度排名前20的细菌累积相对丰度都高于CK，CK和EG在4−8月的最优菌门均为变形菌门(Proteobacteria)。在属水平上，EG提高了土壤细菌中假单胞菌属(Pseudomonas)的相对丰度，同时也会降低硫杆菌属(Thiobacillus)和鬃毛甲烷菌属(Methanosaeta)的相对丰度。通过比较细菌群落结构发现，引入蟹后的EG对细菌群落结构组成的影响远大于采样月的影响。相关性分析表明，TN是影响土壤细菌相对丰度的主要因子，且具有显著性差异(P<0.05)。【结论】 与传统水稻单作(CK)相比，采样稻蟹共作(EG)增强了土壤肥力，提高了土壤中变形菌门和假单胞菌属的相对丰度，有助于提高土壤的肥力和营养循环效率，以及清洁土壤和水体中的污染物。

Abstract:

[Objective] To explore the effects of rice-crab co-culture on physicochemical indicators and microbial community structure of soil in the Yellow River irrigation area of Ningxia and thus provide a theoretical basis for promoting rice-crab farming in the Yellow River irrigation area in northwest China. [Methods] The physicochemical indicators of soil were measured, and high-throughput sequencing of 16S rRNA gene amplicons was employed to reveal the microbial community structure in the fields with only rice planting (CK) and rice-crab co-culture (EG) by introduction of crabs into the ditches around rice plots. [Results] EG had higher soil pH, total nitrogen (TN), and soil organic matter (SOM) and lower total salt content than CK from April to August. The TN, available phosphorus (AP), and SOM in EG were significantly higher than those in CK in June and July. In terms of microbial community structure characteristics, EG significantly altered the bacterial community structure in soil, increasing the bacterial diversity and abundance in April, and August. EG had higher cumulative relative abundance of the top 20 bacterial phyla than CK from April to August. The dominant phylum of both CK and EG from April to August was Proteobacteria. At the genus level, EG increased the relative abundance of Pseudomonas and decreased the relative abundance of Thiobacillus and Methanosaeta. The comparison showed that EG had stronger effect on the bacterial community structure than the sampling month. Correlation analysis shows that TN is the main factor affecting the relative abundance of soil bacteria, and it is significant (P<0.05). [Conclusion] Compared with traditional rice monoculture (CK), sampling rice crab intercropping (EG) enhances soil fertility, increases the relative abundance of Proteobacteria and Pseudomonas in the soil, and helps improve soil fertility and nutrient cycling efficiency, as well as clean up pollutants in soil and water bodies.