Effects Of Rotation(Intercropping) Between Flue-cured Tobacco And Chinese Herbal Medicine On Soil Microbe And Yield And Quality Of Flue-cured Tobacco

Tobacco is an important economic crop in our country,and Chinese herbal medicine Chuanmingshen violaceum and Scrophularia ningpoensis are important medicinal crops.All three are widely cultivated in the southwest region,but there are continuous cropping obstacles in the cultivation process.Crop rotation and intercropping are effective measures to reduce the continuous cropping obstacles.On planting time,C.violaceum is suitable for rotation with tobacco,and S.ningpoensis is suitable for intercropping.The rational allocation of Chinese herbal medicinne and tobacco in tobacco area will promote cooperative development and increase income and efficiency.The paper set field experiment for rotation(continuous cropping as control)and intercropping(monoculture as control)based on flue-cured tobacco,C.violaceum and S.ningpoensis.And adopted Illumina MiSeq high-throughput sequencing to research the soil microbe of rotation and intercropping.Meanwhile,the growth,quality and yield of flue-cured tobacco were determined.The comprehensive analysis of underground microbe and ground plants was used to evaluate the effects order to provide a scientific basis for rotation and intercropping of tobacco with Chinese herbal medicinne.The main results are as follows:1.Rotation of C.violaceum with tobacco increased the biological diversity of bacteria in tobacco soil and changed the community structure.At phylum level,there was no change of the top three phylums,but the content of Proteobacteria and Acidobacteria decreased by 1.73%,1.4%,and Actinobacteria increased by0.65%.At order level,the dominant order and abundance were changed.And there was a tendency that the rotation made eleven orders(such as Acidobacteriales)return to the corn field.At genus level,the abundance of most genera was 0.02~0.50%.In the first 20 dominant genera,9 genera were common.The abundance of each genus increased or decreased at different degrees,and the larger ones were such as uncultured Acidobacteriaceae Subgroup-1,Gemmatimonas.Some genera showed up or disappeared with the crops.The rotation made antagonistic and physiological groups bacteria increase and pathogenic bacteria decrease.2.Rotation of C.violaceum with tobacco increased the biological diversity of fungi in tobacco soil and changed the community structure.At phylum level,compared with tobacco-leisure,Ascomycota decreased by 27.99% to be the subdominant bacteria in tobacco-C.violaceum rotation,Basidiomycota increased by23.69% to be the first advantage.At order level,the order of the first 10 dominant order and its abundance changed greatly.And the rotation make five order(such as Helotiales)return to the corn soil.At genus level,the abundance of most genera was 0.05~5.00%.Only four of the top ten dominant genera were common,and norank Sordariales,norank Agaricomycetes and Phialophora changed greatly in each treatment.Some genera also showed up or disappeared with the crops.Some of the pathogenic fungi were reduced by rotation.3.Rotation of C.violaceum with tobacco had no bad effect on tobacco,and even better than leisure-tobacco.Compared with leisure-tobacco,C.violaceum-tobacco increased the total sugar andpotassium,reduced the nicotine,and coordinated main quality index ratio.In terms of yield,C.violaceum-tobacco increased respectively the fresh weight and dry weight by 9.81% and 6.98%,percentage of superior tobacco increased by 5.06 percentage points.For the economic benefit of flue-cured tobacco,C.violaceum-tobacco had a profit of 308 yuan per mu more than leisure-tobacco.From the annual benefit,C.violaceum-tobacco was far higher than leisure-tobacco,with an income of 7608 yuan per mu.4.The influence of S.ningpoensis and tobacco on bacteria community structure in soil under different planting patterns: Crops and planting patterns all had certain influence on different classification level groups of bacteria,but crops had a greater influence than planting patterns.The richness and diversity of bacteria in S.ningpoensis soil tended to be higher than that in tobacco soil,but differences were not significant.Intercropping slightly increased diversity of bacteria in S.ningpoensis soil.Narrow intercropping slightly reduced richness and diversity of bacteria in tobacco soil,and wide intercropping made richness low but diversity high.But all did not reach significant level.Crops and planting patterns affected the abundance and dominant order at phylum and genus level.At phylum level,Saccharibacteria in tobacco soil was significantly higher than that in S.ningpoensis soil,and Gemmatimonadetes in S.ningpoensis soil was significantly higher than that in tobacco soil.Bacteroidetes was significant difference in different planting patterns.At genus level,the abundance of most genera was 0.01~0.25%.More bacteria genera showed obvious effect of crops,such as unclassified Xanthomonadaceae,norank Saccharibacteria,uncultured Gaiellales in tobacco soil was significantly higher than that in S.ningpoensis soil,whereas norank GR-WP33-30,norank JG30a-KF-32,Gemmatimonas in S.ningpoensis soil was significantly higher than that in tobacco soil.Almost no significant genus affected by planting patterns,but some bacteria such as functional genus Sphingomonas in the individual planting patterns were different from in other treatments.It may be double impact of crops and planting patterns.Principal component analysis also showed that crops had bigger influence than planting patterns.Therefore,bacteria community structure in soil was affected by crops and planting patterns.The influence by crops was bigger and there was obvious crops effect.For the whole of intercropping soil,there were two microbial community structures because of crops.5.The influence of S.ningpoensis and tobacco on fungi community structure in soil under different planting patterns: The richness of fungi in S.ningpoensis soil tended to be higher than that in tobacco soil,but differences were not significant.Intercropping slightly increased diversity of fungi in S.ningpoensis soil.Narrow intercropping slightly reduced richness and diversity of fungi in tobacco soil,and wide intercropping made richness low but diversity high.But all did not reach significant level.Crops and planting patterns also affected the abundance at phylum and genus level.Only a few genus showed the crop effect,such as unclassified Sordariomycetes,Hypocrea.More fungi in individual cropping patterns,,such as the pathogenic genus Cladosporium,Verticillium,differed from in other treatments.It may be double impact of crops and planting patterns.As a result,both crops and cropping patterns affected fungi diversity and community structure,but the crop effect on fungi was weaker than that on bacteria.6.In intercropping of S.ningpoensis and tobacco,the tobacco plants with narrow intercropping were inferior to other planting patterns.Different parts and planting patterns had great influence on tobacco quality.For the quality indexes of middle leaf,the difference between narrow intercropping and monoculture was large,and the difference between wide intercropping and ultra wide intercropping was small.In terms of yield,the fresh weight and dry weight of narrow intercropping were significantly smaller than that of monoculture,which are significantly smaller than that of wide intercropping and ultra wide intercropping.And the inferior tobacco accounted much,the superior little.From the benefit of tobacco,narrow intercropping was the lowest.From the annual benefit,the monoculture tobacco was lowest.According to above analysis of influence on microbe diversity and community structure and the tobacco plant under rotation and intercropping of tobacco with Chinese herbal medicinne: Rotation of C.violaceum with tobacco could improve the microbe community in tobacco soil,and had no adverse effect on tobacco plants,and even had a promoting effect.For intercropping of S.ningpoensis and tobacco,crops and planting patterns had far-reaching influence on soil microbe,and the crops affect on bacteria was stranger than that on fungi.For the whole of intercropping soil,there were two microbial community structures because of crops.The difference of tobacco plants was big under different planting patterns.Wide intercropping was better than monoculture,but it still need to explore more appropriate intercropping patterns.