不同蔬菜与番茄轮作对设施土壤微生物多样性、酶活性及土壤理化性质的影响

Effect of vegetables-tomato rotation on soil microbial diversity, enzyme activity and physicochemical properties of vegetables in greenhouse

摘要:

[目的] 番茄是一种受连作障碍影响明显的蔬菜作物，本试验旨在研究不同蔬菜作物与番茄轮作后对设施土壤微生物多样性、酶活性及土壤理化性质的影响，以期筛选出适宜与番茄轮作的蔬菜作物，为从设施栽培模式选择角度缓解或避免番茄连作障碍提供理论依据。[方法] 试验以连续两茬种植番茄后分别种植大白菜（A）、黄瓜（B）、辣椒（C）、茄子（E）、秋葵（F）、西葫芦（G）6种作物为不同处理，以继续种植番茄（D）和休耕闲置土壤（H）为对照，采用16S rRNA和真菌ITS区测序、同时测定土壤酶活性、pH值、有机质含量、速效氮、磷、钾含量，研究不同蔬菜作物与番茄轮作对土壤微生物多样性、酶活性及土壤理化性质的影响。[结果] 种植作物土壤细菌和真菌多样性指数均显著高于闲置土壤（H）；番茄连作与轮作土壤中的细菌门水平群落结构比较固定，但不同物种的丰度差异较大。真菌对于环境变化的响应比细菌更加敏感，轮作各样本间真菌群落结构差异明显大于细菌群落结构，在物种丰度和门水平上均存在较大差异；轮作茄子和大白菜显著增加了土壤中硝化细菌[亚硝化单胞菌属（Nitrosomonas）、亚硝化螺菌属（Nitrosospira）]的丰度；PCA分析表明轮作茄子和空白闲置土壤细菌和真菌的群落结构与其他处理的差异较大；轮作不同作物土壤酶活性差异显著，但变化规律不明显。轮作大白菜、黄瓜和空白闲置土壤过氧化氢酶活性显著高于番茄连作和轮作其他作物。不同蔬菜轮作土壤肥力主成分分析结果表明土壤pH值、有机质、速效氮与速效磷是主要贡献因子，综合肥力排名第一的为空白土样，其次为轮作黄瓜的土样，综合肥力最低的为轮作茄子土样。[结论] 种植作物可以显著提高土壤微生物多样性；轮作茄子和大白菜显著增加了土壤中硝化细菌的丰度，有利于土壤中氮素代谢和利用；轮作黄瓜和大白菜，显著提高土壤中过氧化氢酶的活性，有利于降低番茄连作产生的自毒作用。因此综合分析认为，茄子、黄瓜和大白菜是避免或缓解番茄连作障碍的潜在优势轮作作物。

Abstract:

[Objective] Tomato is a vegetable that is largely affected by continuous cropping. We investigated the effect of the rotation of different crops and tomato on soil microbial diversity, enzyme activity, and soil physico-chemical properties, with the aim to select rotation crops suitable for tomato and thus to provide a theoretical basis for alleviating or avoiding continuous cropping obstacles in tomato cultivation.[Methods] Together with tomatoes, cultivated over 2 consecutive years, we planted six crops, namely Chinese cabbage (A), cucumber (B), pepper (C), eggplant (E), okra (F), and zucchini (G); treatments with continuous tomato cultivation (D) and temporary non-crop soil (H) were used as controls. Using 16S rRNA and fungal ITS region sequencing, soil enzyme activity, pH value, organic matter content, and available nitrogen, phosphorus, and potassium levels were determined. This enabled us to investigated the effects of the rotation of different vegetable crops and tomato on soil microbial diversity, enzyme activity, and soil physicochemical properties. [Results] The diversity index values of bacteria and fungi in soil from treatments A, B, C, E, F, and G were significantly higher than that in H. The community structure of bacterial phyla in D soil and in A, B, C, E, F, and G soils was relatively stable, albeit with differences in species abundance. Fungi were more sensitive to environmental changes than bacteria, and the differences in fungal community structures were greater than those in bacterial communities. The abundance of nitrifying bacteria (Nitrosomonas and Nitrosospira) in soil was significantly increased by rotation of eggplant and Chinese cabbage in the tomato field. Principal components analysis showed that the community structure of bacteria and fungi in E and H soil was significantly different from that of other treatments. Soil enzyme activity of different crops in rotation soils (A, B, C, E, F and G) was significantly different, but the change law was not obvious. Catalase activity in A, B, and H soil was significantly higher than that in other soils. According to the results of the soil fertility analysis, soil pH, organic matter, available nitrogen, and available phosphorus were the main contributing factors. [Conclusion] Crop cultivation can significantly increase the soil microbial diversity; rotation of eggplant and Chinese cabbage in the tomato field can significantly increase the abundance of nitrifying soil bacteria, which is beneficial to nitrogen metabolism and use. Rotation of cucumber and Chinese cabbage in the tomato field can significantly increase soil catalase activity, which is conducive to reducing the self-toxic effect produced by tomato in continuous cropping mode. Based on our results, eggplant, cucumber, and Chinese cabbage are potential dominant crops for avoiding or alleviating the tomato continuous cropping obstacle.