不同烤烟种植模式对贵州土壤养分、酶活性及细菌群落结构的影响

贵州是我国第二大烤烟种植省份,为获得更高的经济效益,烟区常采用连作的种植模式。本研究采取大田试验,通过设置4个处理:烤烟连作(T)、白菜-烤烟轮作(C-T)、豌豆-烤烟轮作(P-T)、绿肥-烤烟轮作(GM-T),分析不同烤烟种植模式对贵州土壤养分、酶活性及细菌群落结构的影响。结果表明,烤烟轮作使土壤有机质(SOM)、阳离子交换量(CEC)、全氮(TN)、微生物量碳(MBC)、微生物量氮(MBN)和微生物量磷(MBP)分别提高了0.77%~12.44%、10.78%~38.51%、11.76%~17.65%、10.65%~20.67%、36.58%~160.36%和14.66%~36.21%;土壤中铵态氮(AN)、硝态氮(NN)、有效磷(AP)和速效钾(AK)含量分别降低了1.01%~71.67%、19.29%~24.32%、23.09%~52.21%和6.18%~10.09%。与T处理相比,烤烟轮作提高了土壤脲酶和蔗糖酶活性,提升幅度为12.38%~42.96%和4.00%~22.67%,以GM-T处理效果最佳。同时,烤烟轮作提高了细菌OTU数量,并改变了细菌群落的相对丰度,但未对细菌群落组成产生影响。此外,轮作还增加了土壤中有益细菌类群数量,尤其是杆菌类细菌。冗余分析(RDA)结果显示,MBP是驱动群落变异的主要因子,且与黄杆菌属和褚氏杆菌属呈正相关关系。综上所述,通过烤烟轮作可以均衡土壤养分、改善土壤微环境,以GM-T处理效果最佳。本研究结果可为贵州省烤烟的种植提供理论参考,为解决烤烟连作问题提供技术支撑。

Effects of Different Flue-cured Tobacco Planting Patterns on Nutrients,Enzyme Activities and Bacterial Community Structure in Soil of Guizhou Province

Guizhou is the second largest flue-cured tobacco planting province in China. In order to obtain higher economic benefits, continuous cropping is often used in tobacco areas. In this study, a field experiment was conducted to investigate the effects of different tobacco planting patterns on soil nutrients, enzyme activities and bacterial community structure. Four treatments were set as tobacco continuous cropping (T), cabbage - tobacco rotation (C-T), pea - tobacco rotation (P-T), and green manure - tobacco rotation (GM-T). Results showed that the tobacco rotation increased the soil organic matter (SOM), cation exchange capacity (CEC), total nitrogen (TN), microbial biomass carbon (MBC), microbial biomass nitrogen (MBN) and microbial biomass phosphorus (MBP) were increased by 0.77%~12.44%, 10.78%~38.51%, 11.76%~17.65%, 10.65%~20.67%, 36.58%~160.36% and 14.66%~36.21%, respectively, compared with T treatment. The ammonium nitrogen (AN), nitrate nitrogen (NN), available phosphorus (AP) and available potassium (AK) decreased by 1.01%~71.67%, 19.29%~24.32%, 23.09%~52.21% and 6.18%~10.09%, respectively. Compared with T treatment, tobacco rotation enhanced the activities of soil urease and sucrase by 12.38%~42.96% and 4.00%~22.67%, with the best effect of GM-T treatment. Meanwhile, tobacco rotation increased the number of bacterial OTUs and changed the relative abundance of bacterial communities, but had no effect on the bacterial community composition. In addition, tobacco rotation increased the number of beneficial bacteria in the soil, especially Bacillus spp. The results of redundancy analysis (RDA) resulted show that MBP was the main factor driving community variation, and positively correlated with Rhodanobacter and Chujaibacter. In conclusion, tobacco rotation can balance the soil nutrients and improve the soil microenvironment, and the GM-T treatment has the best effect. The results of this study provided theoretical reference for the tobacco cultivation and provide technical support for solving the problem of tobacco continuous cropping.