Changes in the soil microbial community after reductive soil disinfestation and cucumber seedling cultivation

Abstract

Reductive soil disinfestation (RSD) has been proven to be an effective and environmentally friendly way to control many soilborne pathogens and diseases. In this study, the RSDs using ethanol (Et-RSD) and alfalfa (Al-RSD) as organic carbons were performed in a Rhizoctonia solani-infected soil, and the dissimilarities of microbial communities during the RSDs and after planting two seasons of cucumber seedlings in the RSDs-treated soil were respectively investigated by MiSeq pyrosequencing. The results showed that, as for bacteria, Coprococcus, Flavisolibacter, Rhodanobacter, Symbiobacterium, and UC-Ruminococcaceae became the dominant bacterial genera at the end of Al-RSD. In contrast, Et-RSD soil involved more bacteria belonging to Firmicutes, such as Sedimentibacter, UC-Gracilibacteraceae, and Desulfosporosinus. For fungi, Chaetomium significantly increased at the end of RSDs, while Rhizoctonia and Aspergillus significantly decreased. After planting two seasons of cucumber seedlings, those bacteria belonging to Firmicutes significantly decreased, but Lysobacter and Rhodanobacter belonging to the phylum Proteobacteria as well as UC-Sordariales and Humicola belonging to Ascomycota alternatively increased in Al- and Et-RSD-treated soils. Besides, some nitrification, denitrification, and nitrogen fixation genes were apparently increased in the RSD-treated soils, but the effect was more profound in Al-RSD than Et-RSD. Overall, Et-RSD could induced more antagonists belonging to Firmicutes under anaerobic condition, whereas Al-RSD could continuously stimulate some functional microorganisms (Lysobacter and Rhodanobacter) and further improve nitrogen transformation activities in the soil at the coming cropping season.

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“…Similarly, the bacterial and fungal community structures were also changed significantly in the treated soils at this time. Both the bacterial and fungal community structures in the plant residue‐amended RSD soils were similar, but were different from those in the ethanol‐amended RSD soil, which accorded with a previous report (Huang et al, ). Also, the microbial structures in the ethanol‐amended RSD soil were grouped with those in the dazomet‐fumigated soil.…”

“…As an alternative to chemical fumigation, reductive soil disinfestation (RSD), also termed biological soil disinfestation and anaerobic soil disinfestation, was discovered separately in the Netherlands (Blok, Lamers, Termorshuizen, & Bollen, ) and Japan (Shinmura, ). Similar to chemical fumigation, RSD is a pre‐planting soil management strategy that can effectively control a wide range of soil‐borne pathogens (Huang et al, ). Reductive soil disinfestation is an environmentally friendly approach that is implemented by amendment with labile organic matter, such as ethanol, wheat ( Triticum aestivum L.) bran and maize ( Zea mays L.) straw, and by creating anaerobic soil conditions with irrigation and covering the soil with plastic film at a high temperature (>25°C) for 2–4 weeks (Momma, Kobara, Uematsu, Kita, & Shinmura, ).…”

“…During RSD treatment, anaerobic bacteria belonging to the phyla Firmicutes and Proteobacteria considerably increase and inhibit soil-borne pathogens by producing acetic acid, butyric acid, and Fe 2+ and Mn 2+ associated with anaerobic decomposition of added organic materials (Momma, Kobara, & Momma, 2011;Testen & Miller, 2018). The soil physicochemical and microbial properties, such as pH, organic carbon, nutrient contents, microbial population and activity, are also changed considerably after RSD treatment (Di Gioia et al, 2017;Huang et al, 2016). Furthermore, the outcome of RSD varies between different organic substrates (Hewavitharana, Ruddell, & Mazzola, 2014;Huang et al, 2016).…”

“…The soil physicochemical and microbial properties, such as pH, organic carbon, nutrient contents, microbial population and activity, are also changed considerably after RSD treatment (Di Gioia et al, 2017;Huang et al, 2016). Furthermore, the outcome of RSD varies between different organic substrates (Hewavitharana, Ruddell, & Mazzola, 2014;Huang et al, 2016).…”

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“…Factors that influence soil microbial activity exert control over the production of soil enzymes, which then integrate information on soil microbial status and soil physico‐chemical properties, making them a useful sensor for studying the effects of environmental changes in soil fertility . Their activity is well‐correlated with nutrient availability .…”