不同短期轮作模式下氮肥减施对番茄根际土壤微生物群落结构的影响

Effects of Reduced Nitrogen Fertilizer on Tomato Rhizosphere Soil Microbial Community Structure under Short-term Rotation Patterns

摘要:

为探索云南干热区不同施氮量下番茄短期轮作对土壤微生物群落结构的影响，本研究于2023-2025年开展轮作-后茬系统试验，设4种轮作系统（玉米-番茄（CT）、大豆-番茄（ST）、花生-番茄（PT）、番茄-番茄（TT）），每茬均设3个施氮水平（常规施氮量的50%（N1）、75%（N2）和100%（N3））。利用Illumina测序技术扩增子测序，探究不同施氮量下土壤微生物群落结构对不同轮作的响应特征。结果表明，收获期各处理土壤细菌群落以变形菌门、绿弯菌门、放线菌门和酸杆菌门为优势菌门，真菌群落以子囊菌门为优势菌门。在属水平下，镰刀菌属为各处理最大优势真菌菌属，TT处理相对丰度最高且随施氮量增加而增加（TTN3：44.47%），STN2（14.76%）和PTN1（14.71%）处理均较低，且不同轮作处理下，相对丰度随施氮量的变化趋势存在差异。CTN1处理真菌有益菌属木霉菌相对丰度（11.36%）最高。轮作显著提高了微生物群落多样性，STN2处理细菌、真菌Shannon、Simpson指数均达到最高，且显著高于其他处理。而TT处理细菌、真菌Shannon指数显著低于轮作处理，且均随施氮量增加呈先增后减趋势。不同轮作处理和连作处理间的细菌群落结构存在显著差异（P=0.001，R2=0.398，应力为0.127），而真菌群落无显著差异（P=0.597，R2=0.308，应力为0.197）。轮作显著增加番茄产量，且同一轮作模式下，番茄产量随施氮量增加呈先增后减趋势。与TT处理相比，轮作处理产量平均显著增加3.19%，CTN2处理获得最高产量（116.6 t/hm2）。综上所述，短期连作可增加连作障碍风险，而短期轮作有助于抑制病原菌增殖和改善土壤微生物群落结构，进而提高番茄产量，可为该地区的农业可持续发展提供理论支撑。

Abstract:

Aiming to explore the effects of short-term rotation of tomato at different nitrogen application rates on the structure of soil microbial communities in dry-hot regions of Yunnan, a rotation-subsequent crop experiment was conducted from 2023 to 2025, with four rotation systems (corn-tomato (CT), soybean-tomato (ST), peanut-tomato (PT), and tomato-tomato (TT)) and three nitrogen levels (50% (N1), 75% (N2), and 100% (N3) of the conventional nitrogen rate) established for each crop. Amplicon sequencing based on Illumina sequencing technology was employed to explore the responses of soil microbial communities to different rotation patterns at varying nitrogen rates. The results showed that the soil bacterial communities of all treatments were dominated by Proteobacteria, Chloroflexota, Actinobacteriota and Acidobacteriota at harvest, while the fungal communities were dominated by Ascomycota. At the genus level, Fusarium was the most dominant fungal genus of all treatments. The relative abundance of Fusarium was the highest under TT treatment and increased with the increase of nitrogen rate (TTN3: 44.47%), while relatively low abundances were observed under STN2 (14.76%) and PTN1 (14.71%) treatments. In addition, the variation trends of its relative abundance with nitrogen rates differed among different rotation treatments. The relative abundance of Trichoderma, a beneficial fungal genus, was the highest under CTN1 treatment (11.36%). Rotation significantly increased the diversity of soil microbial communities, and the Shannon and Simpson indices of bacteria and fungi under STN2 treatment both reached the maximum values, which were significantly higher than those of other treatments. In contrast, the Shannon indices of bacteria and fungi under TT treatment were significantly lower than those under rotation treatments, and both exhibited a trend of first increasing and then decreasing with the increase of nitrogen rate. There were significant differences in the bacterial community structure between different rotation and continuous cropping treatments (P=0.001, R2=0.398, stress was 0.127), while no significant differences were observed in the fungal community structure (P=0.597, R2=0.308, stress was 0.197). Rotation significantly increased tomato yield, and under the same rotation pattern, it was increased first and then decreased with the increase in nitrogen rate. Compared with TT treatment, the yield of rotation treatments significantly increased by an average of 3.19%, and CTN2 treatment achieved the highest yield (116.6 t/hm2). In conclusion, short-term continuous cropping may increase the risk of continuous cropping obstacles, while short-term rotation was conducive to inhibiting the proliferation of pathogenic bacteria, improving the structure of soil microbial communities, and thereby increasing tomato yield, which can provide a theoretical basis for the sustainable agricultural development in this region.