Final report for LNC17-393
Project Information
This project, entitled “Optimizing anaerobic soil disinfestation (ASD) to manage emerging soilborne diseases in tomato protected culture systems in the North Central Region”, addresses an emerging issue in intensive vegetable farming systems. Higher demand for local produce as well as increasing weather extremes have led to expanded adoption of greenhouse and high tunnel vegetable production systems in the North Central United States. ASD is a promising approach to suppress soilborne disease and promote soil health and crop productivity. Research was conducted to optimize ASD for tomato production in high tunnels, focusing on carbon sources used during ASD, including agricultural plant byproducts and cover crops. Higher rates of plant byproducts tended to result in better outcomes (disease suppression and/or plant biomass), and soybean meal, wheat midds, and distiller's dried grains proved to be most effective as ASD carbon sources. These were selected for on-farm trials, conducted using the "Mother Baby Trials" approach. Replicated Mother trials were established on six farms to evaluate these carbon sources, while Baby trials with wheat midds were established on nine farms in late summer/autumn 2018. Post ASD bioassays and soil sampling for microbial community analysis were conducted. Cooler than normal temperatures led to lowered efficacy of the ASD treatment. Farmer and Extension educator participation monitoring using Outcome Mapping was used to assess levels of participation among individual boundary partners.
Our project will lead to both learning and action outcomes to benefit vegetable farmers in the North Central Region. We will increase farmers’ awareness and understanding of soilborne diseases and potential methods for managing these diseases through workshops and factsheets. Farmers will learn the skills to apply ASD through workshops and participatory on-farm trials. Ultimately, achievement of these learning outcomes will lead to action outcomes, including farmer adoption of ASD and integrated soilborne disease management strategies. The findings of our project will benefit farmers, extension agents, and plant health professionals.
Continuous production with little rotation in protected culture vegetable production systems has resulted in the emergence of soilborne disease complexes that greatly reduce yield, quality, and profitability, especially in tomato production. Key diseases in these complexes include Verticillium wilt (Verticillium dahliae), black dot root rot (Colletotrichum coccodes), corky root rot (Pyrenochaeta lycopersici), and root knot nematode (Meloidogyne spp.). Management of soilborne diseases historically relied on environmentally damaging, energy intensive methods, such as fumigation and steam sterilization. Anaerobic soil disinfestation (ASD) is a promising disease management tactic in which soil is amended with a carbon source, irrigated to saturation, and tarped for several weeks. ASD is driven by and has a tremendous impact on beneficial soil microbial communities and soil health, yet our understanding of these impacts is not complete. Nor has ASD been evaluated or optimized for the North Central Region. It is critical to counter the effects of soilborne diseases on the sustainability of protected culture systems. The objectives of this project are to 1) optimize ASD for protected tomato culture, 2) generate new knowledge about how ASD affects soilborne diseases, beneficial soil microbes, and soil health, and 3) increase awareness and adoption of ASD technology in the region. The outcomes of the project are increased 1) farmer awareness and understanding of soilborne diseases and their management, 2) farmer understanding of the uses, mechanisms and benefits of ASD for disease management, and 3) adoption of ASD and integrated soilborne disease management strategies by community farmer-leaders leading to region-wide adoption. We will achieve these objectives and outcomes through greenhouse and growth chamber trials to optimize ASD and by participatory on-farm trials using the mother and baby trial design, which will allow us to introduce, evaluate and disseminate ASD in one series of trials. The impacts of ASD on soil health and soil microbial communities will be examined in the mother portion of these trials. Project progress will be evaluated using Outcome Mapping, which fosters close collaboration between program participants.
Cooperators
- (Educator)
- (Educator)
- (Educator)
Research
- Anaerobic soil disinfestation (ASD) efficacy against soilborne fungal pathogens of tomato depends on the type and rate of carbon source used.
- ASD suppresses plant pathogenic microorganisms while improving soil microbial community structure and soil health.
- ASD suppresses soilborne diseases of tomato and increases yields in high tunnel systems.
- Outcome Mapping is an effective tool to monitor project progress and stakeholder engagement and predict adoption of effective technologies.
Evaluation of agricultural byproducts as ASD carbon sources. Experiments were conducted to assess the effects of anaerobic soil disinfestation (ASD) carbon sources (wheat bran, distillers’ dried grain, whey, corn gluten, and soybean meal) and rates (9 t/a and 4.5 t/a) on various soilborne diseases of tomato (corky root rot, black dot root rot, root knot nematode). Soils from three tomato high tunnels from three Ohio counties (Wayne, Erie, and Highland) with a known history of soilborne diseases were used in these experiments. Experiments were laid as randomized complete block design with 5 replications. Each experiment was conducted twice.
Soils were placed in 9 oz plastic cups, amended with a carbon source, flooded with sterile distilled water, covered with black plastic mulch, and sealed with rubber bands and electrical tape. Two controls were used in these experiments, a non-amended, flooded, covered control (anaerobic control) and a non-amended, flooded, and uncovered control (aerobic control). An IRIS (Indicator of Reduction in Soil) rod was inserted into the soil in each cup. Cups were placed in growth chamber at 77°F (25° C) with no light for four weeks. After four weeks, cups were taken from the growth chamber, five holes were punched into the bottom of the cups using a nail, and cups were returned to the growth chamber for one week to dry. After one week of drying, soils were placed in a plastic bag and homogenized with a rubber mallet. Homogenized soils were returned to cups and two-week-old tomato ‘Moneymaker’ seedlings were placed in each pot. Tomatoes were grown in the greenhouse for 9 weeks at which time plants were harvested and roots were washed. Roots were evaluated for root rot (percent of roots rotten or discolored) and taproot rot using a 1 to 5 scale (1: no root rot, 2: 1 to 2 small lesions on the taproot, 3: multiple lesions covering less than 50% of the taproot, 4: multiple lesions covering more than 50% of the taproot, 5: taproot completely rotten or missing). No nematode galls were not present so nematodes were not rated.
Following root rating, a subsample of roots from each plant was plated onto three plates of half strength potato dextrose agar. After two weeks, fungi growing on the medium were identified morphologically.
Evaluation of cover crops as ASD carbon sources. Eight cover crops were assessed for efficacy as ASD carbon sources: two grasses (Sorghum sudangrass and winter rye), three legumes (cowpea, crimson clover, and white clover), two Brassicas (mustard and oilseed radish), and buckwheat. Cover crops were direct seeded (5-7 seeds per pot) in a topsoil blend in Deepots (D40H) and were fertilized weekly with a 20-20-20 fertilizer. After seven weeks, the aboveground portion of the cover crop was harvested and cut by hand into 0.25-0.75 cm pieces. The cover crops were mixed at a rate of 9 t/a with soil obtained from a high tunnel in Highland County, OH and placed into 9 oz cups. Wheat midds were included as a separate treatment as a known effective ASD carbon source. IRIS rods were placed into cups, and cups were sealed and placed in the growth chamber as described above. Soils, planting, and assessment occurred as described above for the carbon source trials. Experiments were laid as randomized complete block design with 5 replications. Each experiment was conducted twice.
On-farm evaluation of ASD. Trials were established using the mother and baby trial design. Mother trials are large, randomized complete block design trials with multiple treatments laid by researchers on a farm and managed by the farmer, while baby trials are small, farmer-laid completely randomized trials with usually only one treatment. Quantitative data on treatment performance is gathered by researchers from mother trials, while farmers’ opinions on their experience with ASD treatment are gathered from baby trials. The mother and baby trial method is an efficient means of introducing, evaluating and disseminating a new disease management strategy.
Larger, compensated on-farm “mother” trials were established in high tunnels on six Amish farms in four Ohio counties (Wayne, Holmes, Knox, Morrow). In these trials, the effects of ASD with wheat midds (nutritionally equivalent to wheat bran but less expensive), soybean meal, or distillers’ dried grains on soilborne diseases of tomatoes are being compared to non-amended soils (Figure 1). On-farm trials were laid as a randomized complete block design with four replications. Plots were 3 ft wide and ranged in length from 10-30 ft depending on the size of the high tunnel. Carbon sources were spread over the treated area and incorporated to a depth of 4-6 in using a walk behind rototiller. Beds were formed by hand and then two lines of drip tape were laid on top of each bed. Black plastic mulch was laid over each bed and the sides of the mulch were covered with soil to prevent air exchange. Non-amended, covered plots serve as the controls. The irrigation was turned on until soils were saturated to a depth of 8 in. Plots remained covered for 4-6 weeks, depending on the weather. Temperatures in treated and control soils were monitored using HOBO pendant temperature data loggers (Onset Computer Corporation, Bourne, MA), buried 15 cm deep in each of two plots per treatment.
Soil samples were collected immediately after the end of ASD treatment from a depth of 15 cm. Soil samples were divided for soil testing, soil health testing, post-ASD bioassays, and DNA extraction. For DNA extractions, soil samples were air dried in sealed coin envelopes in a fume hood for 12 hours. DNA was extracted from homogenized soil samples after the brief drying period using the MoBio Powersoil DNA extraction kit (Mobio Laboratories, Inc. a Qiagen Company, Carlsbad, CA) with two DNA extractions were performed per soil sample. Three trials (Holmes, Knox, and Morrow) were selected to conduct high throughput amplicon sequencing of bacterial and fungal communities.
Post-ASD bioassays were conducted on soil samples collected immediately following ASD treatment. Tomato ‘Moneymaker’ seeds were planted in pots (Deepots, 262 mL) containing ASD-treated or control soils collected from field plots. Plants were fertilized once weekly with a 20-20-20 N-P-K fertilizer. Tomatoes were grown in the greenhouse for nine weeks. Plants were harvested and roots were rinsed in running tap water to remove soil. Plants were assessed for dry shoot and root biomass, root rot severity, root knot nematode galling (if applicable) and taproot rot severity as described above. The experiment was laid as a randomized complete block design with four reps. Fungi were isolated from root systems as described above and plated onto two plates 1/2APDA per root system.
Soil samples were collected again in March-April 2019 and August 2019, representing pre-planting and late season/harvest sampling times. Soil samples were processed as before for soil testing and DNA extraction, but were not used for bioassays for these later sampling points.
For soil testing, soils collected at each time point were subjected to standard soil testing (Spectrum Analytic, Washington Court House, OH) and soil health testing including permanganate oxidizable carbon, soil protein and soil respiration.
Farmers grew tomatoes using their standard practices and preferred tomato varieties (Mountain Fresh, Red Deuce, or Bigdena). Participating farmers recorded yield data from three plants at the center of each plot during the growing season. At season’s end, roots were collected from these three plants and assessed for root rot.
Nine farmers were provided with supplies to conduct baby trials. Four trials were in the vicinity of Knox and Morrow counties and five trials were in the vicinity of Wayne and Holmes counties. A survey was sent to baby trial participants in fall 2019 and responses were received from six participants.
Outcome Mapping. Outcome challenges and progress markers were created for three sets of boundary partners: mother trial farmer participants, baby trial participants, and Extension educators. Boundary partners are the stakeholder groups that you want to impact in a project. Following the end of the mother trial setup, mother trial participants and Extension educators were evaluated for applicable progress markers. The survey sent to baby trial participants was used to assess progress markers for this boundary partner.
Evaluation of agricultural byproducts as ASD carbon sources. ASD using any of the carbon sources and rates tested led to the development of reducing conditions in the treated soils compared to the control soils, as indicated by percentage iron oxide paint loss from IRIS tubes (Figure 2). Root rot was significantly lower in tomatoes grown in ASD-treated soil regardless of carbon source and rate than in the non-ASD controls. The lowest root rot values (Fig. 2) were observed for plants grown in soils treated with high rates of distiller's dried grains (12.9%), soybean meal (13.9%), corn gluten (14.8%), and wheat bran (15.7%). Dry shoot and root biomass were significantly affected by ASD treatment. The highest root and shoot biomasses were observed in plants grown in soils treated with the high rates of soybean meal and corn gluten (Fig. 2).
Figure 2. Results of screening various agricultural byproducts for efficacy as ASD carbon sources. Amount of iron oxide paint loss (A), root rot severity (B), dry shoot biomass (C), and dry root biomass (D) are shown. Corn gluten meal (CG), distillers dried grains (DG), soybean meal (SM), wheat bran (WB), and dry sweet whey (WY) were evaluated as ASD carbon sources in bioassays at low (L, 4.5 tons per acre) and high (H, 9 tons per acre) amendment rates and performance was compared to aerobic and anaerobic controls. Treatment means are indicated by diamonds and means that do not share the same letters differ significantly based on Tukey's HSD with a 95% family-wise confidence level. From Testen et al. 2021 Frontiers in Sustainable Food Systems
Although ASD with corn gluten significantly reduced tomato root rot and increased tomato biomass, phytotoxic effects were observed on tomato seedlings produced in soil amended with corn gluten. For this reason, corn gluten was not selected as a carbon source for the field trials.
Evaluation of cover crops as ASD carbon sources
Application of ASD with any cover crop led to the development of reducing conditions (Fig 3). However, soils amended with wheat midds had the highest levels of iron oxide paint loss and were significantly higher than any carbon source. The highest levels of iron oxide paint loss were observed in soils amended with either sorghum sudangrass or crimson clover.
Use of wheat midds as an ASD carbon source led to significantly lower levels of roots rot severity compared to controls and all cover crops, except crimson clover or sorghum sudangrass (Fig 3). Use of sorghum-sudangrass, crimson clover, white clover, or winter rye as ASD carbon sources led to significantly lower levels of root rot severity compared to the aerobic control.
Use of cover crops as ASD carbon sources did not significantly impact root or shoot biomass (Fig 3.).
Figure 3. Results of screening of cover crops for efficacy as ASD carbon sources. Amount of iron oxide paint loss (A), root rot severity (B), dry shoot biomass (C), and dry root biomass (D) are shown. Treatments means are indicated by diamonds and means that do not share the same letters differ significantly based on Tukey's HSD with a 95% family-wise confidence level. From Testen et al. 2021 Frontiers in Sustainable Food Systems
On farm evaluations of ASD
Average soil temperatures for the trials were low and ranged from 53.6-63.1 F. These low temperatures likely effected the efficacy of the ASD treatments compared to our previous high tunnel studies (see Testen et al. 2021 Phytopathology 111:954-965). Despite low temperatures, reducing conditions did develop in all trials, albeit at lower amounts than in trials conducted with warmer temperatures.
Yield was not significantly impacted by ASD treatment. Root rot severity of plants grown in either soybean meal or wheat midds amended plots trended lower than in control plots (Table 1). In post-ASD bioassays, a similar trend in root rot severity was observed but root rot associated with the soybean meal treatment was significantly lower than in the non-treated control.
Table 1.Mean soil reducing conditions, root rot severity, and yield from on-farm trials conducted to assess three anaerobic soil disinfestation carbon sources (9 t/acre). From Testen et al. 2021 Frontiers in Sustainable Food Systems
Impacts on soil health
Standard soil testing results are shown for pooled data across all trials (Table 2). Levels of magnesium, calcium, and cation exchange capacity were not significantly impacted following ASD. Use of distillers dried grains led to a slight but significant reduction in pH and phosphorus content in distillers dried grain amended soils compared to control soils following ASD. Organic matter slightly but significantly increased following ASD. Potassium levels were also significantly higher in soybean meal or distillers dried grains plots compared to control plots following ASD (Table 2).
Table 2 Soil properties based on standard soil testing immediately following ASD. Data shown is pooled from all trials. Properties measured include pH, organic matter (%), phosphorus (ppm), potassium (ppm), magnesium (ppm), calcium (ppm) and cation exchange capacity. Means in a column that do not share the same letters differ significantly based on Tukey's HSD with a 95% family-wise confidence level.
|
|
pH |
OM |
P |
K |
Mg |
Ca |
CEC |
|
Wheat midds |
6.77ab |
3.2a |
419.6ab |
271.9bc |
444.5 |
2577.1 |
15.4 |
|
Soybean meal |
6.86ab |
3.1ab |
397.5ab |
386.8a |
440.5 |
2667.9 |
15.5 |
|
Distillers dried grains |
6.68b |
3.1a |
380.5b |
292.0b |
435.8 |
2626.8 |
15.3 |
|
Control |
6.91a |
2.8b |
438.8a |
225.3c |
425.2 |
2738.5 |
15.0 |
|
P-value |
0.023 |
0.002 |
0.025 |
<0.0001 |
0.45 |
0.083 |
0.75 |
At harvest, levels of organic matter, phosphorus, potassium, magnesium, calcium or cation exchange capacity did not differ significantly (Table 3). Soil pH was slightly but significantly lower in soybean meal amended plots compared to control plots (Table 3).
Table 3 Soil properties based on standard soil testing at harvest sampling point. Data shown is pooled from all trials. Properties measured include pH, organic matter (%), phosphorus (ppm), potassium (ppm), magnesium (ppm), calcium (ppm) and cation exchange capacity. Means in a column that do not share the same letters differ significantly based on Tukey's HSD with a 95% family-wise confidence level.
|
|
pH |
OM |
P |
K |
Mg |
Ca |
CEC |
|
Wheat midds |
6.80a |
2.9 |
501.7 |
269.1 |
431.7 |
2856.0 |
15.8 |
|
Soybean meal |
6.50b |
2.9 |
447.2 |
267.6 |
419.8 |
2819.1 |
16.1 |
|
Distillers dried grains |
6.68ab |
2.6 |
456.1 |
260.1 |
422.0 |
2811.3 |
15.3 |
|
C |
6.85a |
2.7 |
468.5 |
261.1 |
419.8 |
2742.6 |
15.1 |
|
P-value |
<0.0001 |
0.027 |
0.092 |
0.969 |
0.900 |
0.707 |
0.277 |
Soil health results are shown individually for the three trials (Holmes, Knox and Morrow) in which microbial communities were also characterized. Results at the post-ASD and harvest sampling times are shown.
Active carbon was not significantly impacted by ASD in the three trials for sampling either immediately following ASD or at harvest (Figure 4). Similarly, ASD did not consistently impact soil protein levels (Figure 5). For Holmes and Knox trials, soil protein was significantly higher in soil amended with soybean meal compared to control soils immediately following ASD. At harvest, levels of soil protein did not differ significantly for any trial. Microbial respiration (Fig. 6) was significantly greater for nearly all ASD treatment for the Holmes and Knox trials immediately following ASD. At harvest, significant differences in soil respiration were not observed.
Figure 4 Active carbon levels (mg of permanganate oxidizable carbon per kg of soil) for soils from three ASD trails (Holmes, Knox, and Morrow) immediately following ASD or at harvest. Bars that do not share the same letters differ significantly based on Tukey's HSD with a 95% family-wise confidence level.
Figure 5: Soil protein levels (g protein for kg soil) for soils from three ASD trails (Holmes, Knox, and Morrow) immediately following ASD or at harvest. Bars that do not share the same letters differ significantly based on Tukey's HSD with a 95% family-wise confidence level.
Figure 6: Soil respiration levels (Mineralized C per g soil) for soils from three ASD trails (Holmes, Knox, and Morrow) immediately following ASD or at harvest. Bars that do not share the same letters differ significantly based on Tukey's HSD with a 95% family-wise confidence level.
Impacts on soil microbial communities
Soil bacterial and fungal communities were characterized by high throughput sequencing for three trials. Anaerobic soil disinfestation led to reduced diversity, as measured by Shannon’s H’, in both bacterial and fungal communities. Immediately following ASD, bacterial diversity (Fig. 7) was significantly lower in soybean meal amended plots for all trials, in distillers dried grain amended plots for the Holmes and Morrow trials, and in wheat midds plots for the Morrow trial. At harvest, bacterial community diversity was significantly lower in soybean meal amended plots than control plots for the Knox and Holmes trials. Fungal diversity (Fig. 8) was reduced significantly compared to controls in the Holmes (soybean meal) and Morrow (all carbon sources) county trials following ASD treatment. At harvest, fungal diversity did not significantly differ in any trials.
We can examine the relative abundance (percent reads of a specific sequence out of all sequence reads) to infer how ASD impacted specific genera. For genus Clostridium, an anaerobic bacterium important in ASD, the relative abundance of this genus was generally elevated (Fig. 9) in ASD treated soils compared to control soils immediately following ASD. At harvest, Clostridium relative abundance was not elevated, except in the Holmes trial. For Pyrenochaeta spp. including P. lycopersici, the relative abundance of Pyrenochaeta spp. (Fig. 10) was generally reduced in ASD-treated plots compared to control plots immediately following ASD. However, at harvest, the relative abundance of Pyrenochaeta did not differ significantly for any trial indicating that Pyrenochaeta populations may have rebounded during the growing season.
Fig 7. Soil bacterial diversity (Shannon's H') in soils from three ASD trails (Holmes, Knox, and Morrow) immediately following ASD or at harvest. Bars that do not share the same letters differ significantly based on Tukey's HSD with a 95% family-wise confidence level.
Fig. 8 Soil fungal diversity (Shannon's H') in soils from three ASD trails (Holmes, Knox, and Morrow) immediately following ASD or at harvest. Bars that do not share the same letters differ significantly based on Tukey's HSD with a 95% family-wise confidence level.
Fig. 9 Relative abundance of Clostridium spp. sequences in soils from three ASD trails (Holmes, Knox, and Morrow) immediately following ASD or at harvest. Bars that do not share the same letters differ significantly based on Tukey's HSD with a 95% family-wise confidence level.
Fig. 10 Relative abundance of Pyrenochaeta spp. sequences in soils from three ASD trails (Holmes, Knox, and Morrow) immediately following ASD or at harvest. Bars that do not share the same letters differ significantly based on Tukey's HSD with a 95% family-wise confidence level.
Outcome Mapping
Outcome mapping was used to track progress by three boundary partners: mother trial farmers, baby trial farmers and extension educators. We developed 15 progress markers for mother trial farmers (Table 4), 16 for baby trial farmers (Table 5) and 11 for extension educators (Table 6). Nearly all boundary partners met all “expect to see” progress markers. “Expect to see” progress markers demonstrate baseline expected behaviors or actions by participants if the project is running as it should. There was variability in mother trial farmers meeting “like to see” progress markers. “Like to see” progress markers indicate mid to late term project changes in behaviors and actions related to project goals. Progress markers related to trial maintenance and collecting yield data were met, but progress markers related to trial feedback and connecting with other farmers were rarely met. For “love to see” markers (those that you would observe if the project is changing participants behaviors to adopt and disseminate the introduced technology), only one farmer met 1 of 3 progress markers. Baby trial farmer participation was tracked using a survey and 6 of 9 participants responded to the survey. Half of “like to see” progress markers were met by half or more of participating baby trial farmers and at least one participant met each of the three “love to see” progress markers. Extension educators met 4 of 6 “like to see” progress markers and 0 of 2 “love to see” markers. Extension Educators could not engage in the project as much as originally desired due to high workloads.
Outcome mapping effectively allowed researchers to identify which project areas and participants were and were not meeting their expected goals. While we were not able to track participants as closely as we desired due to departure of the postdoctoral researcher, outcome mapping was still a useful tool to track changes in behaviors, actions, and knowledge that can be associated with changes in plant disease management practices by participants.
Table 4: Outcome challenge and progress markers for mother trial farmers
|
Outcome challenge for mother trial farmers: Farmer participates in anaerobic soil disinfestation trials, provides feedback on the on-farm trials, and introduces other farmers to anaerobic soil disinfestation. |
|
|
Expect to see |
|
|
1. Farmer volunteers independently for mother trials |
6/6 |
|
2. Farmer asks questions about trial setup |
6/6 |
|
3. Farmer provides space in high tunnels for trials |
6/6 |
|
4. Farmer preps space prior to ASD setup |
5/6 |
|
5. Farmer reads provided literature (factsheets) on ASD and soilborne diseases of tomato |
6/6, all farmers discussed with researcher |
|
6. Farmer is present when trials are set up |
5/6 |
|
Like to See |
|
|
5. Farmer helps recruit other farmers to participate in mother or baby trials |
1/6 |
|
6. Farmer expresses a desire to contribute knowledge to the “greater good” in order to manage plant diseases |
2/6 |
|
7. Farmer actively participates in trial setup |
1/6 |
|
8. Farmer invites neighboring farmers to see trials set up or trials in progress |
2/6 |
|
9. Farmer maintains trials throughout the growing season |
4/6 (two trials lost due to health reasons and tunnel collapse) |
|
10. Farmer contacts OSU researchers or Extension educators if there are questions during the growing season |
2/6 |
|
11. Farmer collects yield data during the growing season |
4/4 (two trials lost due to extenuating circumstances) |
|
12. Farmer provides his/her opinions on ASD during the growing season |
2/6 |
|
Love to See |
|
|
13. Farmer suggests changes to ASD practice or make suggestions for how they would apply it |
0/6 |
|
14. Farmer applies ASD in more high tunnels |
1/6 |
|
15. Farmer introduces technology to other farmers |
0/6 |
Table 5: Outcome challenge and progress markers for baby trial farmers
|
Outcome challenge for baby trial farmers: Farmer conducts small anaerobic soil disinfestation trial on their own farms and provides feedback on the technique. |
|
|
Expect to See |
|
|
1. Farmer volunteers to participate in baby trials |
6/6 |
|
2. Farmer reads provided literature (factsheets) on ASD and soilborne diseases of tomato |
6/6 |
|
3. Farmer identifies problem areas to treat |
4/6 |
|
4. Farmer asks questions about ASD and trial setup |
1/6 |
|
5. Farmer sets up trial |
6/6 |
|
Like to See |
|
|
6. Participating farmer suggests other farmers to participate in baby trials |
0/6 |
|
7. Farmer expresses a desire to contribute knowledge to the “greater good” in order to manage plant diseases |
1/6 |
|
8. Farmer invites neighboring farmers to trial setup or trials in progress |
2/6 |
|
9. Farmer asks questions to OSU researchers or Extension educators if needed |
1/6 |
|
10. Farmer compares ASD-treated areas to untreated areas |
6/6 |
|
11. Farmer provides opinions on ASD application |
3/6 |
|
12. Farmer seeks out other soilborne disease management practices |
4/6 |
|
13. Farmer expresses desire to participate in more research opportunities |
4/6 |
|
Love to See |
|
|
14. Farmer intends to apply ASD to entire production area (adoption) |
1/6 |
|
15. Farmer introduces ASD technology to other farmers |
2/6 |
|
16. Farmer suggests changes to ASD practice or makes suggestions for how they would apply it |
2/6 |
Table 6: Outcome challenge and progress markers for Extension Educators
|
Outcome Challenge for Extension Educators: Extension educator assists with the anaerobic soil disinfestation (ASD) mother and baby trials, facilitates communication between researchers and farmers, and learns how to apply the mother and baby design for their own work. |
|
|
Expect to See |
|
|
1. Extension educator agrees to participate in coordinating ASD trials |
2/2 |
|
2. Extension educator communicates with researchers about trials |
2/2 |
|
3. Extension educator facilitates communication between researchers and farmers |
1/2 |
|
Like to See |
|
|
4. Extension educator suggests farmers to participate in trials |
2/2 |
|
5. Extension educator participates in trial setup and learns how to apply ASD |
2/2 |
|
6. Extension educator aids farmers in collecting yield data |
0/2 |
|
7. Extension educator recommends ASD to farmers in their county |
1/2 |
|
8. Extension educator disseminates factsheets on ASD/soilborne disease management in tomato |
2/2 |
|
9. Extension educator suggests ASD to extension educators/farmers in other counties
|
0/2 |
|
Love to See |
|
|
10. Extension educator uses mother and baby trial design for other research projects
|
0/2 |
|
11. Extension educator gives independent presentation on ASD and soilborne disease management
|
0/2 |
In this project, we identified several factors to improve use of ASD in North Central conditions. First, we identified optimal rates for carbon sources derived from agricultural byproducts and identified several byproducts that could be used in place of wheat bran/midds. We also identified several cover crops that reduced soilborne disease severity when used as ASD carbon sources but not to the same level of efficacy as ag byproducts carbon sources. Future research on supplementing cover crops with agricultural byproducts and using these mixtures as ASD carbon source may help boost the efficacy of cover crops as carbon sources.
Efficacy of ASD on on-farm trials was limited by low temperatures during treatment. This, unfortunately, limited the conclusions that we can draw from these trials. However, we did observe moderate impacts of ASD on soilborne diseases, soil properties, and soil microbial communities. These impacts are likely accentuated when ASD occurs under warmer conditions. Future work is needed to determine the interactions between temperature, amendment rates, and tarping periods in ASD so that growers can adjust their treatment for changing temperatures. Methods to improve ASD efficacy at cooler soil temperatures would also be beneficial to growers.
We disseminated information on our findings through in-person extension talks, webinars, blog posts and a scientific article. Use of outcome mapping to track project progress was a useful tool and can be adapted to other plant health studies.
Education
Our educational approach was multi-faceted. First, we presented information on the use and efficacy of anaerobic soil disinfestation (ASD) to manage soilborne diseases and weeds to farmers, Extension educators, consultants and other researchers in grower meetings and technical conferences in several states. Secondly, we provided farmers with hands-on experience using ASD through the "Mother and Baby Trial" approach, maintaining close contacts with participating farmers and Extension educators, and monitoring progress through Outcome Mapping. Finally, we developed blog posts/newsletter articles and scientific publications on ASD to reach a broad cross-section of the specialty crop community.
Project Activities
Educational & Outreach Activities
Participation Summary:
Education/outreach description:
During 2018, we interacted with farmers, consultants, Extension educators and researchers on the benefits and utilization of anaerobic soil disinfestation (ASD) for suppression of soilborne diseases and weeds in vegetable crops. We participated in five Crop Walks in five Ohio counties (total 450 participants) and made presentations to the Great Lakes Expo (Grand Rapids, MI; 100 participants) and the Southern Ohio Specialty Crop School (Loveland, OH; 20 participants. Technical presentations on ASD were made during the 33rd Annual Tomato Disease Workshop (Chincoteague, VA), the 9th International IPM Symposium (Baltimore, MD), and the International Congress of Plant Pathology (ICPP2018), Boston, MA (two ASD presentations and one presentation on Outcome Mapping). In 2019, we participated in crop walks, grower meetings, workshops and seminars. In 2020, due to pandemic restrictions on travel and face-to-face interactions, interactions with stakeholders were virtual after mid-March 2020. Thanks to a project extension due to the COVID pandemic, we were able to reach more growers and researchers in 2020 and 2021. Below are Extension outputs and seminars for the entire span of the project.
Extension presentations
Testen, A. 2021. Soilborne diseases and what you can do about them in high tunnels. Ohio State Virtual High Tunnel Workshop. (virtual, 140 participants)
Miller, S. A., Testen, A. L. and Khadka, R. Anaerobic soil disinfestation (ASD) to control soilborne diseases. Ohio Produce Network Grower Meeting, Columbus, OH. January 23, 2020. (in person; 35 attendees)
Rotondo, F. and Miller, S. A. Utilizing OSU Diagnostic Services for Specialty Crops - Vegetable Insect, Disease & Weed Update. OSU Agriculture and Natural Resources Ag Madness Webinar series. April 23, 2020. (virtual, 40 attendees)
Miller, S. A. 2019. Managing soilborne diseases of tomatoes in high tunnels using anaerobic soil disinfestation and grafting. Mid-Atlantic Fruit and Vegetable Convention, Hershey, PA. 215 participants.
Miller, S. A. 2019. Managing root knot nematode and other soilborne diseases using ASD. Ohio Produce Network, Columbus, OH. 35 participants.
Miller, S. A. 2019. Managing soilborne diseases. Mid-Ohio Growers Meeting, Mt. Hope, OH. 125 participants.
Miller, S. A. and Testen, A. L. ASD: Anaerobic soil disinfestation - greenhouse. Great Lakes Expo Fruit, Vegetable and Farm Market, Grand Rapids, MI, December 10-11, 2019. 75 participants.
Miller, S. A. and Testen, A. L. ASD: Anaerobic soil disinfestation – high tunnels. Great Lakes Expo Fruit, Vegetable and Farm Market, Grand Rapids, MI, December 10-11, 2019. 30 participants.
Extension publications
Miller, S. A. and Testen, A. L. 2019. Managing soilborne diseases of tomatoes in high tunnels using anaerobic soil disinfestation and grafting. Proceedings, Mid-Atlantic Fruit and Vegetable Convention, Hershey, PA.
Miller, S. A. and Testen, A. L. 2019. ASD: Anaerobic soil disinfestation. Great Lakes Expo Fruit, Vegetable and Farm Market, Grand Rapids, MI, December 10-11.
Miller, S. A. 2019. Plant health check - get to the root of it. Ohio Veggie Disease News, September 18 blog post. https://u.osu.edu/miller.769/2019/09/28/plant-health-check-get-to-the-root-of-it/
Invited Seminars
Testen, A. 2021. Managing soilborne diseases in Midwestern vegetable production through anaerobic soil disinfestation. The Ohio State University Department of Horticulture and Crop Science, Wooster, OH. 35 attendees.
Miller, S. A. 2020. Harnessing beneficial microbes for soilborne disease management in small- to mid-scale vegetable production systems. UC Davis Dept. Plant Pathology Seminar, Davis, CA, March 2, 2020 (in-person; 35 attendees).
Miller, S. A. 2019. Benefits and challenges of on-farm research to solve vegetable crop management problems. The Ohio State University Dept. Horticulture and Crop Science Seminar, Wooster, OH, February 27, 2019. 40 attendees.
Testen, A. 2019. Anaerobic soil disinfestation to manage soilborne diseases in Midwestern vegetable production systems. Iowa State University Department of Plant Pathology and Microbiology, Ames, IA. October 22, 2019. 50 attendees.
Journal Articles
Testen, A. L., Rotondo, F., Mills, M. P. Horvat, M. M. and Miller, S. A. 2021. Evaluation of agricultural byproducts and cover crops as anaerobic soil disinfestation carbon sources for managing a soilborne disease complex in high tunnel tomatoes. Frontiers in Sustainable Food Systems doi: 10.3389/fsufs.2021.645197.
Learning Outcomes
- Awareness of soilborne diseases in high tunnel tomatoes
- Anaerobic soil disinfestation as a soilborne disease mitigation tactic in high tunnel tomatoes