PLASTIC FILM ALTERS SOIL PHYSICOCHEMICAL PROPERTIES AND MICROORGANISMS, AFFECTING THE GROWTH OF CIGAR TOBACCO

In recent years, frequent extreme drought and rainfall have seriously affected crop production.Film mulching has been applied to dry farming, but little is known about its influence on cigar tobacco growth in high-temperature, high-humidity environments.Here, in our study, plastic film was used as a soil mulching materials to investigate its influence on soil physicochemical properties, tobacco growth and rhizosphere soil microorganisms.The un-mulched soil served as the control.The results showed that the film mulching significantly increased soil organic matter (OM), available phosphorus (AP), available potassium (AK), chlorophyll and nicotine in tobacco leaf, while decreasing total sugar, reducing sugar and starch.Redundancy analysis further showed that OM, AP and AK were significantly positively correlated with chlorophyll a, lutein and carotenoid (p < 0.05).Principal component analysis (PCA) indicated that film mulching significantly influenced the community structure of rhizosphere soil microorganisms, and decreased the relative abundance of Proteobacteria, but increased the relative abundance of Chytridiomycota, Firmicutes and Chloroflexi.These increased species were significantly positively correlated with AP and AK (p < 0.05).Besides, the film mulching significantly increased the abundance of beneficial microorganisms (Bacillus), and decreased the abundance of pathogens (Fusarium), thereby controlling the occurrence of bacterial wilt.Our findings indicated that film mulching promotes cigar tobacco growth by improving soil physicochemical properties and microorganisms in high temperature and humidity environment.