Exploring warm-season cover crops as carbon sources for anaerobic soil disinfestation (ASD)

Experiments were conducted to evaluate potential functional and mechanistic differences in the suppression of Sclerotinia sclerotiorum and S. minor and root-knot nematodes in muck soils by anaerobic soil disinfestation (ASD) using different carbon source amendments. Volatile compounds produced during ASD in muck soil amended with molasses, wheat bran, or mustard greens at 20.2 Mg/ha or a 2% ethanol solution significantly reduced the mycelial growth and number of sclerotia produced by both Sclerotinia spp. compared with the anaerobic control. In amended soils, acetic and butyric acids were detected in concentrations that reduced the viability of sclerotia of both pathogens. Higher concentrations of carbon dioxide were observed in ASD-treated soils, regardless of the amendment, than in the nonamended anaerobic control. Only amendment with wheat bran did not increase the production of methane gas during ASD compared with the controls. Meloidogyne hapla survival was completely suppressed in soils treated with ASD regardless of carbon source. Field trials were conducted in Ohio muck soil to assess survival of sclerotia of both Sclerotinia spp. The viability of sclerotia of both Sclerotinia spp. was significantly reduced in soil subjected to ASD amended with wheat bran (20.2 Mg/ha), molasses (10.1 Mg/ha), or wheat bran (20.2 Mg/ha) plus molasses (10.1 Mg/ha) compared with the controls. A consistent negative correlation between soil reduction and viability of sclerotia of both pathogens was observed. Wheat bran and molasses are both widely available amendments that can be used as ASD carbon sources for the management of soilborne pathogens in muck soils.

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Maltose and Totally Impermeable Film Enhanced Suppression of Anaerobic Soil Disinfestation on Soilborne Pathogens and Increased Strawberry Yield

Sustainability ◽

10.3390/su12135456 ◽

2020 ◽

Vol 12 (13) ◽

pp. 5456

Author(s):

Zhaoxin Song ◽

Dongdong Yan ◽

Wensheng Fang ◽

Bin Huang ◽

Xianli Wang ◽

...

Keyword(s):

Crop Production ◽

Carbon Sources ◽

Field Trials ◽

Soilborne Pathogens ◽

Fusarium Spp ◽

Soil Disinfestation ◽

Soil Nutrition ◽

Anaerobic Soil Disinfestation ◽

Phytophthora Spp ◽

Bacterial Microbiota

Anaerobic soil disinfestation (ASD) is widely used to control soilborne diseases in organic crop production. The effect of ASD used different sealed films on soilborne pathogens and strawberry growth was evaluated in two laboratory studies and two field trials. Under maltose as carbon sources, 28 °C temperature and 30% of soil moisture optimal conditions ASD decreased Fusarium spp. and Phytophthora spp. by 100%. ASD used maltose as an organic amendment and sealed with totally impermeable film (TIF) obtained the highest suppression (>96%) against Fusarium spp. and Phytophthora spp. (>91%). According to the laboratory results, the efficacy of ASD utilizing 6 or 9 t/ha maltose and sealing with TIF was evaluated and compared with reference treatment with chloropicrin (Pic) or solarization (Sol) in the field trials. Compared with the untreated soil, ASD treatments greatly reduced the pathogenic population of Fusarium spp. and Phytophthora spp., and successfully controlled the damage of fusarium wilt with evidence of lower mortality (6%). ASD significantly increased soil nutrition promoted plant growth and increased strawberry yield, which was similar as the Pic, but better than Sol treatment. The analyzed fungal and bacterial microbiota did not show significant differences in the taxonomic richness and diversity between the compared treatments. Nevertheless, the abundance of some bacterial and fungal taxa tended to change between treated. The evidence showed that adding maltose and sealing TIF for ASD has the potential to replace Pic for pathogen control in commercial strawberry production.

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Synergy of Anaerobic Soil Disinfestation and Trichoderma spp. in Rhizoctonia Root Rot Suppression

Frontiers in Sustainable Food Systems ◽

10.3389/fsufs.2021.645736 ◽

2021 ◽

Vol 5 ◽

Author(s):

Ram B. Khadka ◽

Sally A. Miller

Keyword(s):

Carbon Source ◽

Rhizoctonia Solani ◽

Wheat Bran ◽

Root Rot ◽

Carbon Sources ◽

Chicken Manure ◽

Treated Soil ◽

Soil Disinfestation ◽

Anaerobic Soil Disinfestation ◽

Rhizoctonia Root Rot

Potential synergy between anaerobic soil disinfestation (ASD) and Trichoderma spp. in suppression of Rhizoctonia root rot in radish was evaluated. A split-plot design with three replications was used; main plots were Trichoderma harzianum T22, Trichoderma asperellum NT25 and a non-Trichoderma control. Subplots were ASD carbon sources wheat bran, molasses, chicken manure, and mustard greens and two non-amended controls: anaerobic (covered and flooded) and aerobic (not covered or flooded). Carbon sources and Rhizoctonia solani inoculant were mixed with soil, placed in pots, and flooded, followed by drenching Trichoderma spore suspensions and sealing the pots in zip-lock bags. After 3 weeks, bags were removed, soil was aired for 1 week and radish “SSR-RR-27” was seeded. Rhizoctonia root rot severity and incidence were lowest in radish plants grown in ASD-treated soil amended with wheat bran, molasses, or mustard greens across all Trichoderma treatments. Disease severity was lower in radish plants treated with NT25 than with T22 or the non-Trichoderma control across all ASD treatments, and in radish grown in ASD-treated soil amended with wheat bran plus NT25 compared to ASD-wheat bran or NT25 alone. Rhizoctonia solani populations were significantly reduced by ASD treatment regardless of carbon source, while Trichoderma populations were not affected by ASD treatment with the exception of ASD-mustard greens. The interactions of either Trichoderma isolate and ASD with most carbon sources were additive, while T22 with ASD-molasses and NT25 with ASD–wheat bran interactions were synergistic in reducing disease severity. One interaction, T22 with ASD-chicken manure was antagonistic. Enhancement of ASD efficacy in suppressing soilborne diseases such as Rhizoctonia root rot by additional soil amendment with Trichoderma spp. during the process appears to be dependent on both Trichoderma isolate and ASD carbon source.

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Plant-Derived Carbon Sources for Anaerobic Soil Disinfestation in Southern California

Global Journal of Agricultural Innovation Research & Development ◽

10.15377/2409-9813.2021.08.13 ◽

2021 ◽

Vol 8 ◽

pp. 169-175

Author(s):

Oleg Daugovish ◽

Joji Muramoto ◽

Carol Shennan ◽

Margherita Zavatta

Keyword(s):

Rice Bran ◽

Carbon Sources ◽

Cost Effective ◽

Fruit Production ◽

Grape Pomace ◽

Management Tools ◽

Soil Disinfestation ◽

Anaerobic Soil Disinfestation ◽

Coffee Grounds ◽

Spent Grain

Anaerobic soil disinfestation (ASD) has been optimized and adopted as an organic alternative to chemical fumigation by strawberry growers in California. The ASD process relies on mixing labile carbon sources into the soil to generate chemical, physical, and microbiological changes aiding suppression of the soil-borne pathogens and enhancing fruit production. Continued ASD adoption is hindered by the increasing cost of rice bran, currently the most widely used carbon source. To address this need and to find suitable and economical alternative carbon sources, we conducted field evaluations of locally produced or sourced plant-based products. ASD with incorporated grass-sod clippings spent grain and coffee grounds from one supplier provided a 47% to 83% increase in fruit yields compared to untreated soil, but coffee grounds from a different supplier decreased strawberry yields. Carbon, nitrogen, and their ratios had important impacts on the efficacy of ASD with coffee grounds and grape pomace. ASD with wheat midds at 20 t/ha provided strawberry yields similar to chloropicrin-fumigated soil while substituting 30% of rice bran carbon rate with on-site grown cereal cover crop biomass resulted in yields similar to the full rate of rice bran but at a reduced cost. As we continue exploring cost-effective methods of soil disinfestation, we utilize ASD integrated with other pest management tools, such as the use of resistant cultivars and crop rotation for sustainable production.

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Integrating Cover Crops as a Source of Carbon for Anaerobic Soil Disinfestation

Agronomy ◽

10.3390/agronomy10101614 ◽

2020 ◽

Vol 10 (10) ◽

pp. 1614

Author(s):

Luca Vecchia ◽

Francesco Di Gioia ◽

Antonio Ferrante ◽

Jason C. Hong ◽

Charles White ◽

...

Keyword(s):

Cover Crops ◽

Cover Crop ◽

Low Cost ◽

Second Phase ◽

Crop Species ◽

Soil Disinfestation ◽

Anaerobic Soil Disinfestation ◽

Lettuce Yield ◽

Alternative Sources ◽

The Impact

The adoption of anaerobic soil disinfestation (ASD), a biologically-based method for the management of soilborne pests and pathogens at the commercial scale strictly depends on the availability of effective and low-cost sources of carbon (C). A three-phase pot study was conducted to evaluate the performance of twelve cover crop species as alternative sources of C in comparison to molasses. Buckwheat produced the greatest above-ground and total plant dry biomass and accumulated the largest amount of total C. In the second phase, simulating the application of ASD in a pot-in-pot system, molasses-amended soil achieved substantially higher levels of anaerobicity, and lowered soil pH at 3 and 7 days after treatment application compared to soil amended with the cover crops tested. In the third phase of the study, after the ASD simulation, lettuce was planted to assess the impact of cover crops and molasses-based ASD on lettuce yield and quality. The treatments had limited effects on lettuce plant growth and quality as none of the treatments caused plant stunting or phytotoxicity. Tested cover crop species and molasses had a significant impact on the availability of macro and micro-elements in the soil, which in turn influenced the uptake of minerals in lettuce. Fast growing cover crops like buckwheat or oat, capable of accumulating high levels of C in a relatively short time, may represent a viable alternative to substitute or be combined with standard C sources like molasses, which could provide an on-farm C source and reduce cost of application. Further research is needed to assess the performance of cover crops at the field scale and verify their decomposability and efficacy in managing soil-borne pests and pathogens.

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Weed Control Assessment of Various Carbon Sources for Anaerobic Soil Disinfestation

International Journal of Fruit Science ◽

10.1080/15538362.2020.1774472 ◽

2020 ◽

Vol 20 (sup1) ◽

pp. 1005-1018

Author(s):

Danyang Liu ◽

Jayesh B. Samtani ◽

Charles S. Johnson ◽

David M. Butler ◽

Jeffrey Derr

Keyword(s):

Weed Control ◽

Carbon Sources ◽

Soil Disinfestation ◽

Anaerobic Soil Disinfestation

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Composted Chicken Manure for Anaerobic Soil Disinfestation Increased the Strawberry Yield and Shifted the Soil Microbial Communities

Sustainability ◽

10.3390/su12166313 ◽

2020 ◽

Vol 12 (16) ◽

pp. 6313

Author(s):

Zhaoxin Song ◽

Sebastien Massart ◽

Dongdong Yan ◽

Hongyan Cheng ◽

Mathilde Eck ◽

...

Keyword(s):

Carbon Sources ◽

Soil Microbial Communities ◽

Ammonium Nitrogen ◽

Chicken Manure ◽

Marketable Yield ◽

Soil Disinfestation ◽

Soil Microbial ◽

Soil Nutrition ◽

Anaerobic Soil Disinfestation ◽

Oxidation Reduction

Anaerobic soil disinfestation (ASD), as a bio-fumigation technology, has been developed to control soil-borne pests. There is increasing evidence showing that carbon sources and cover tarps play an important role in the ASD suppression of soil-borne pests, but little is known about the effect of composted chicken manure (CCM) and totally impermeable films (TIF) against soil-borne pests in the strawberry production system. In experiments, the colonies of Fusarium spp. and Phytophthora spp., which are recognized to cause strawberry soil-borne diseases, decreased significantly after ASD. The soil promoted a significant increase in ammonium nitrogen, nitrate-nitrogen and organic matter, but a decrease in oxidation-reduction potential after ASD. Besides, the strawberry plant height, stem thickness and yield were significantly higher than in the non-amended soil. Compared to the untreated control, ASD, both at 6 and 12 ton/ha of CCM, significantly (p = 0.05) increased strawberry marketable yield and income. The economic benefit could be due to the suppression of soil-borne diseases and the improvement of soil nutrition. The soil bacterial and fungal diversity and richness increased after soil fumigation. The increased presence of biological control agents led to the suppression of soil-borne pathogens. In summary, ASD with CCM amendments could be applied in pre-plant fumigation to control strawberry soil-borne pests, strengthen soil fertility, improve crop yield and increase growers’ income.

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Effects of Anaerobic Soil Disinfestation on Sclerotinia sclerotiorum in Paraguay

Plant Health Progress ◽

10.1094/php-12-18-0082-rs ◽

2019 ◽

Vol 20 (1) ◽

pp. 50-60

Author(s):

Andres D. Sanabria-Velazquez ◽

Anna L. Testen ◽

Guillermo A. Enciso ◽

Laura C. Soilan ◽

Sally A. Miller

Keyword(s):

Carbon Source ◽

Sclerotinia Sclerotiorum ◽

Wheat Bran ◽

Carbon Sources ◽

Significant Negative Correlation ◽

Field Trials ◽

Plastic Mulch ◽

Soil Disinfestation ◽

Anaerobic Soil Disinfestation ◽

Reducing Conditions

The effects of anaerobic soil disinfestation (ASD) on Sclerotinia sclerotiorum sclerotia viability was tested in four field trials in Paraguay. Plots were amended with wheat bran (20.2 Mg/ha), molasses (10.1 Mg/ha), or wheat bran (20.2 Mg/ha) plus molasses (10.1 Mg/ha), saturated with water, and covered with black plastic mulch for 3 weeks. Control plots were not amended but were saturated and either covered (anaerobic control) or maintained uncovered (aerobic control). Tubes painted with iron oxide paint were placed in soils to assess soil reducing conditions. Sclerotia were buried 6 cm deep in treated and control soils along with temperature data loggers. After 3 weeks, the viability of sclerotia was significantly lower in all ASD-treated soils (4 to 52%) compared with the aerobic control soil (100%), regardless of the carbon source used. Sclerotial viability was also significantly reduced compared with anaerobic controls at three sites, depending on the carbon source used. A significant negative correlation between soil reducing conditions and sclerotia viability was observed at all sites. Wheat bran and molasses are widely available and inexpensive in Paraguay, and ASD with these carbon sources provides smallholder South American vegetable farmers with a new option for sustainable management of Sclerotinia and potentially other soilborne pathogens.

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Analysis of Environmental Variables and Carbon Input on Soil Microbiome, Metabolome and Disease Control Efficacy in Strawberry Attributable to Anaerobic Soil Disinfestation

Microorganisms ◽

10.3390/microorganisms9081638 ◽

2021 ◽

Vol 9 (8) ◽

pp. 1638

Author(s):

Shashika S. Hewavitharana ◽

Emmi Klarer ◽

Joji Muramoto ◽

Carol Shennan ◽

Mark Mazzola

Keyword(s):

Disease Control ◽

Fusarium Wilt ◽

Environmental Variables ◽

Incubation Temperature ◽

Soil Microbiome ◽

Charcoal Rot ◽

Soil Disinfestation ◽

Anaerobic Soil Disinfestation ◽

Input Type ◽

Incubation Duration

Charcoal rot and Fusarium wilt, caused by Macrophomina phaseolina and Fusarium oxysporum f. sp. fragariae, respectively, are major soil-borne diseases of strawberry that have caused significant crop losses in California. Anaerobic soil disinfestation has been studied as an industry-level option to replace soil fumigants to manage these serious diseases. Studies were conducted to discern whether Gramineae carbon input type, incubation temperature, or incubation duration influences the efficacy of this disease control tactic. In experiments conducted using ‘low rate’ amendment applications at moderate day/night temperatures (24/18 °C), and carbon inputs (orchard grass, wheat, and rice bran) induced an initial proliferation and subsequent decline in soil density of the Fusarium wilt pathogen. This trend coincided with the onset of anaerobic conditions and a corresponding generation of various anti-fungal compounds, including volatile organic acids, hydrocarbons, and sulfur compounds. Generation of these metabolites was associated with increases in populations of Clostridium spp. Overall, carbon input and incubation temperature, but not incubation duration, significantly influenced disease suppression. All Gramineae carbon inputs altered the soil microbiome and metabolome in a similar fashion, though the timing and maximum yield of specific metabolites varied with input type. Fusarium wilt and charcoal rot suppression were superior when anaerobic soil disinfestation was conducted using standard amendment rates of 20 t ha−1 at elevated temperatures combined with a 3-week incubation period. Findings indicate that anaerobic soil disinfestation can be further optimized by modulating carbon source and incubation temperature, allowing the maximum generation of antifungal toxic volatile compounds. Outcomes also indicate that carbon input and environmental variables may influence treatment efficacy in a target pathogen-dependent manner which will require pathogen-specific optimization of treatment protocols.

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