Abstract:

In order to explore the effects of rotation of flue-cured tobacco and different crops on soil quality control of long-term continuous cropping， 4 rotation treatments were set， including barley and flue-cured tobacco （YCDM）， garlic and flue-cured tobacco （YCDS）， rape and flue-cured tobacco （YCYC）， and broad bean and flue-cured tobacco （YCCD）， and the tobacco planting plots with continuous cropping for more than 10 years was used as control （CK）. The physicochemical properties， enzyme activities and microbial community structures of soils under different rotation treatments were analyzed. Based on correlation analysis and redundancy analysis， the relationship between soil physicochemical properties， enzyme activities and microbial community structure was analyzed. The results showed that， compared with CK， soil bulk density decreased by 26.58%~30.29% and total porosity increased by 21.13%~48.26%. Compared with CK， soil pH， available nitrogen （AN）， available phosphorus （AP） and available potassium （AK） contents under the YCCD treatment significantly increased by 11.84%， 30.57%， 6.42% and 41.1%， respectively. Compared with CK， the activities of catalase （CAT）， invertase （INV）， urease （URE） and acid phosphatase （ACP） increased by 16.81%~42.35%， 38.09%~51.48%， 7.69%~64.29% and 5.82%~76.33%， respectively. The YCCD mode had the most significant improvement effect. The results of high-throughput sequencing showed that the OTUs of bacteria under rotation treatments was significantly higher than that of CK. The α-diversity showed that the richness and diversity of bacterial communities were significantly different among different rotation treatments. The richness of fungal communities was significantly different， but the diversity was not. The results of β-diversity analysis showed that the differences of soil fungal communities among different rotation treatments were small， and the differences of soil bacterial communities were large. Among them， YCCD treatment had the largest difference in bacterial and fungal communities compared with CK. At the phylum level， the YCCD treatment increased the relative abundance of Acidobacteria and Actinobacteria， while decreased the relative abundance of Ascomycota. Correlation analysis and redundancy analysis showed that URE， AN， AK and pH were the key factors affecting soil microbial community structure. In conclusion， reasonable rotation of flue-cured tobacco and other crops could improve soil available nutrient content and soil enzyme activity， and then regulate soil microbial community structure， which could reduce the obstacles of continuous cropping of flue-cured tobacco， and finally achieve the goal of stable yield and increase of flue-cured tobacco.

Key words: tobacco planting soil, crop rotation, physical and chemical properties of soil, soil enzyme activity, microbial community

摘要：

为探究烤烟与不同作物轮作对长期连作植烟土壤质量调控的效果，以连作10年以上的植烟田块为对照（CK），设置大麦-烤烟（YCDM）、大蒜-烤烟（YCDS）、油菜-烤烟（YCYC）和蚕豆-烤烟（YCCD）共4种不同作物与烤烟轮作，分析不同轮作处理下土壤的理化性质、酶活性及微生物群落结构。基于相关性分析和冗余分析，解析土壤理化性质和酶活性与微生物群落结构间的关系。结果表明，轮作处理的土壤容重较CK降低26.58%~30.29%，总孔隙度增加21.13%~48.26%；其中烤烟-蚕豆（YCCD）轮作模式下土壤的pH、水解氮（available nitrogen，AN）、有效磷（available phosphorus，AP）和速效钾（ available potassium，AK）含量较CK显著提高11.84%、30.57%、6.42%和41.5 1%。轮作处理的土壤过氧化氢酶（catalase，CAT）、蔗糖酶（invertase，INV）、脲酶（urease，URE）和酸性磷酸酶（acid phosphatase，ACP）的活性较CK分别提高16.81%~42.35%、38.09%~51.48%、7.69%~64.29%和5.82%~76.33%，蚕豆-烤烟（YCCD）轮作模式的提升效果最为显著。高通量测序结果表明，轮作处理下细菌的OTUs数量显著高于CK。α多样性显示，不同轮作处理间的细菌群落丰富度和多样性差异显著；真菌群落的丰富度差异显著，而多样性差异不显著。β多样性分析显示，不同轮作处理之间土壤真菌群落差异较小，细菌群落差异较大。其中，蚕豆-烤烟（YCCD）轮作处理的细菌、真菌群落与CK差异较大。在门水平，烤烟-蚕豆（YCCD）轮作使酸杆菌门（Acidobacteria）和放线菌门（Actinobacteria）的相对丰度增加，子囊菌门（Ascomycota）的相对丰度减少。相关性分析和冗余分析表明，URE、AN、AK和pH是影响土壤微生物群落结构的关键因子。综上所述，烤烟与其他作物合理轮作可提高土壤速效养分含量和土壤酶活性，调节土壤微生物群落结构，消减烤烟连作障碍，最终达到烤烟稳产、增产的目的。

关键词: 植烟土壤, 轮作, 土壤理化性质, 土壤酶活性, 微生物群落