Effect of plastic mulching on mycotoxin occurrence and mycobiome abundance in soil samples from asparagus crops

Abstract

Plastic mulching (PM) is widely used in modern agriculture because of its advantageous effects on soil temperature and water conservation, factors which strongly influence the microbiology of the soil. The aim of this study was to assess the effect of PM on mycotoxin occurrence in relation with mycobiome abundance/diversity and soil physicochemical properties. Soil samples were collected from green (GA) and white asparagus (WA) crops, the last under PM. Both crops were cultivated in a ridge-furrow-ridge system without irrigation. Samples were analyzed for mycotoxin occurrence via liquid chromatography coupled to high-resolution mass spectrometry (LC-HRMS). Total colony-forming unit was indicative of mycobiome abundance, and analysis of mycobiome diversity was performed by internal transcribed spacer (ITS) sequencing. PM avoided the drop of soil temperature in winter and allowed higher soil temperature in early spring compared to non-covered soil. Moreover, the use of PM provided controlled conditions for water content in soil. This was enough to generate a dissimilar mycotoxin occurrence and mycobiome diversity/abundance in covered and non-covered soil. Mycotoxin soil contamination was confirmed for deoxynivalenol (DON), range LOD to 32.1 ng/g (LOD = 1.1 ng/g). The DON values were higher under PM (average 16.9 ± 10.1 ng/g) than in non-covered soil (9.1 ± 7.9 ng/g); however, this difference was not statically significant (p = 0.09). Mycobiome analysis showed a fungal compartment up to fivefold higher in soil under PM compared to GA. The diversity of the mycobiome varied between crops and also along the soil column, with an important dominance of Fusarium species at the root zone in covered soils.

Effects of biodegradable plastic film mulching on soil microbial communities in two agroecosystems

“…In this study, soil microbial community composition was not significantly altered by mulch type. This is in contrast to other studies that have reported altered bacterial communities in soils under BDMs (Koitabashi et al, 2012;Li et al, 2014b;Muroi et al, 2016), and under non-biodegradable plastic mulches (Farmer et al, 2017;Munoz et al, 2015). Such opposite findings could be due to differences in methodology: For example, the studies by Koitabashi et al (2012) and Muroi et al (2016) were shorter laboratory incubation studies in controlled conditions (28 • C to 30 • C), used pure polymer feedstock rather than commercial film formulations which include plasticizers and other additives, and relied on different detection methods such as polymerase chain reaction-denaturing gradient gel electrophoresis (PCR-DGGE).…”

Structural and Functional Responses of Soil Microbial Communities to Biodegradable Plastic Film Mulching in Two Agroecosystems

“…Characterizing the soil microbial communities under the different biodegradable mulches and non-biodegradable PE mulch revealed no significant effect of mulch type on bacterial community structure. This is in contrast to other studies that have reported altered bacterial communities in soils under BDMs (29, 40, 41), and under non-biodegradable plastic mulches (42, 43). Such opposite findings could be due to differences in methodology: for example, the studies by Koitabashi et al (40) and Muroi et al (41) were shorter laboratory incubation studies in controlled conditions (28 to 30°C), used pure polymer feedstock (rather than commercial film formulations which include plasticizers and other additives) and relied on detection methods such as polymerase chain reaction-denaturing gradient gel electrophoresis (PCR-DGGE).…”

Influence of film mulching on soil microbial community in a rainfed region of northeastern China

“…Previous studies mainly focused on the impacts of PFM on soil moisture, soil structure, soil nutrition and crop yield, while their influences on the soil micro-ecological environment and the evolution of soil microbial community were neglected 9 . Just as different groups of microorganisms vary in their ability to adapt to the various soil environmental conditions, changes on soil microbiology under PFM application are expectable 10 . Li et al .…”