Using winter canola and high-glucosinolate mustards to protect and improve soil resources and enhance on-farm profitability

Environmental Conditions for 2013/2014/2015

The winter conditions during the experimental period were considerably colder, providing less snow cover at various points in time during the winter than they had been in 2010 or 2012. These were the years when both PIs in VT and ME had successful production. In some years and some locations parts of fields may have had excellent survival (see Image 1), but when any ice accumulated, losses were high (see Images 2 - 4). Large patches of ice smothered areas of studies killing all of the canola and created a weed management mess the following spring/summer. A nice image of this can be found in Figures 1a – 1d. No WC was planted in ME in the winter of 2014/2015. A WC variety trial was planted in VT, and there was almost complete loss as the average survival was 2.3%. Over the last three growing seasons of WC studies in ME and VT, the average of survival has been 19% in VT and Central ME and 0 % in Northern ME.

5a. Winter Canola Trials – 2012 and 2013

Variety by Potassium Trials

As mentioned, there was poor survival in all WC trials conducted in any year.   Potassium additions did not improve survival in any year. We can conclude that added K accumulated in the crop will not protect it from winterkill. We did find some varietal differences in the survival rates found among varieties in the variety x potassium rate studies. The top four survivors were Kiowa, Dynasty, Wichita and Riley. The same eight varieties were planted again in a trial at the Rogers Farm in Stillwater, ME on August 22, 2013. Presented in Table 1 are the variety survival rates.

In Figure 1, yields of the eight WC varieties are presented from Stillwater, 2014, the only time we were able to collect yield data. Dynastie, Hornet and Riley yielded the highest, and not surprisingly, also had the best survival. These yields were as high as they were because we had to hand weed due to the low plant populations after poor winter survival. Winter canola is a highly plastic crop and can fill in gaps and produce well if not over run with weeds. Figure 1 shows the yield of eight WC varieties at Stillwater 2013/2014.

Figure 2 shows the yield and winter survival of the seventeen WC varieties planted in Alburg, VT in the 2013-2014 season. Winter survival ranged from 0-35.6%, the trial average was 15.8%. Yields are presented “as is” when harvested due to the weediness of the seed causing difficulty in moisture determination with our moisture meter. The highest yielding varieties produced 1600-1800 lbs., however if these yields were corrected for moisture they would likely be among the lowest yielding varieties in ME. Although statistical differences were seen for winter survival, all varieties were below 40% which caused more weed pressure in the spring and made harvest and cleaning the seed more difficult.

Potassium additions were not found to significantly affect yield or survival in either state. While winter survival affected yield, potassium did not significantly add to winter survival.

Planting Date X Seeding Rate Trial

In both states, we found mixed results with different seeding rates. Essentially the take home message is that winter survival is more affected by environment than anything else, and if you plant at a higher seeding rate, it does not help. Everything planted north of central ME failed in both years. So data presented below include only the Stillwater locations for the Maine and the Alburgh location for VT. The best planting dates were the late august or very early in September. With too much plant growth in the fall, the plants are more likely to have winter damage. Planted too late, the plants could be frost heaved out of the soil or killed by dessication. Variety appeared to have more influence on winter survival than seeding date or rate. Generally a 4 – 5 pound seeding rate appeared to be as effective as any other. It appears that if the conditions are conducive for winterkill, all the plants seem to die regardless of seeding rate. See Table 2.

Soil Management Trial

The final trial we conducted was a soil management/planting trial to assess the benefit of rolling a field prior to drilling, rolling a field after drilling or simply drilling in the seed.   As can be seen in Table 3, rolling the field both prior to and following drilling seed can help germination, but did not significantly improved winter survival or yield in either season. While one might think the extra management might reduce infiltration, our results suggest that possibly frost heaving is reduced with a more compacted soil. See Table 3.

In contrast to the variety trial, higher survival in the soil preparation study did not lead to higher yield (Figure 7). Despite the lack of yield differences, packing a field after harvest is a good management practice given the size of the seed.

Summary

Under our best conditions, WC yields produced about 30% higher than the average spring canola yields for this area. However, if you add the two failed crops seasons in Aroostook county, the one failed season in central ME and the failed two failed seasons in VT, WC production is way riskier and poorer than spring canola. Even in the better years, the variation in yield across the fields was largelydue large patches of dead canola. The weed issues caused by Austrian winter cress and other weeds growing without WC competition in these areas were also problematic. Based on the data collected in these trials, we would not want to promote WC in northern New England due to the questionable survival. But, if a grower were to want to try, these are the protocols we have developed to enhance the potential for success.  

• Select fields that are likely to have improved drainage, or have sufficient slope such that water will not pool and freeze.
• Select the most winter hardy variety you can find: Riley, Dynastie and Hornet were the best varieties for ME.
• When planting, have a smooth prepared seedbed and roll the field after drilling as a minimum to ensure good seed to soil contact.
• Plant between the third or fourth week in August and the first week of September for Central ME and VT. This appears to provide a sufficient length of time to ensure good rooting / cover establishment, but not so much time as to develop too much leaf area that might hurt winter survival.
• Plant at a 4 to 5 lb per acre seeding rate. We did not find any advantage to a higher seeding rate.
• Ensure that your potassium levels in the soil are moderate to high, but there did not appear to be any benefit to higher added rates of potassium.

Results – High Glucosinolate Mustard Studies

Key Findings: As mentioned in the summary, fall planted and incorporated HGM did not appear to be as effective in controlling black scurf and common scab in potatoes as season long planted HGM cover crops. High glucosinolate mustard biomass yields are similar if planted by early or middle august, but since they are not incorporated until almost November, the cool air and soil temperatures do not seem to generate the same amount of glucosinolate gassing effect as when these crops are destroyed and incorporated in late August.

Biomass Production ranged from 3400 to over 7000 lbs. dry matter per acre for the cover crops planted dependent on weather conditions and planting dates. The earlier these cover crops can be planted the greater the yield will be which is important for improving soil quality and return on seed costs.   However the effect on potato and bean yield and quality was poor across the Experiment station and on-farm experiments and years.

Key Findings in HGM studies:

• HGM makes an excellent competitive cover crop
• Highest yields were found if planted by first week of August.

  • Higher yield led to greater potato production in 2013 but not in 2014

• HGM is a more effective biofumigant crop if planted as a season-long cover crop (eg. planted in June and incorporated in August).
• HGM will absorb N left from a previous crop (potato, corn etc.)
• Added nutrients, particularly N, significantly boosts yields
• Regionally available (Pacific and Ida Gold) mustard seed is equally effective in yield and effect as special lines of HGM mustards which would be more expensive
• Late planted cover crops come with a soil moisture risk; if too dry, mustard can take a long time or even fail to germinate

Summary

            We did not see the reduction in potato skin surface disease expression that we found in previous studies. In conversations with researchers in Idaho doing similar planting dates and cover crop destruction protocols, they have found less effect as well. There are a couple of possible explanations. While biomass amounts are similar to amounts produced in full season plantings, it is possible that the amount of glucosinolates generated by the plant or glucosinolate activity is lower or less when the weather and soil temperatures are cooler at the time of destruction and incorporation.   In almost every instance, the control plot had higher levels of scab and black scurf, but the differences are less than what we found in the previous work. It is unfortunate as growers can get a harvestable crop off the field and leave the field covered through the fall. October cover crop incorporation seems to be a much better fit for farmers, but from the data we have collected, it has not been nearly as effective.

Accomplishments/Milestones

We will introduce 600 ME and VT potato and vegetable growers to the concept of growing WC and HGM crops through presentations at conferences, production meetings, articles in newsletters, and visits to Extension websites.

            In Table 8, we outlined all of the educational program that we have delivered as part of this project. In total, in the greater New England / Northeast region, we reached over 1500 farmers about this method. Data and trial information was made available in websites and reports. Examples include:

*Also, the UVM Extension oilseed website (www.uvm.edu/extension/cropsoil/oilseeds) was visited 889 times.

PDFs of sample program announcement flyers are included in Appendix A.

We exceeded the expectations of this goal. Over the three years, through meetings, website visits and other means, we easily reached twice the expected number of growers with information on WC and HGM cover crops/rotations.

Fifteen of the 20 current ME and VT spring canola growers will attend oilseed producers meeting and learn about WC production opportunities.

An oilseed growers meeting was held in March 2013 and 2014. We had 138 people attend, and several growers announced that they have initiated growing WC in VT. We had four growers and Andrew Plant attend this meeting attend from ME. Another oilseed growers meeting was held in March 2014 for 43 growers. At that meeting we discussed the results of our press evaluation and aspects of small scale oil pressing for biodiesel or human consumption including demonstrations of on-farm culinary oil processing equipment. We have met this goal of reaching all current spring canola growers with information on benefits and risks (mostly the latter) of growing winter canola.

Of the 600 ME & VT vegetable and potato growers that learn about HGM production, 50 growers will seek further information about HGM growth and management by December 2013.

We presented information at several grower events (see above). Since we did not find positive results with HGM, most growers did not seek additional information. However a small population of 5 farmers have requested additional information and even started to experiment on their own farms.  So while we may not have reached this goal, we have certainly had interest in the topic. Jemison presented information on HGM as far away as Prince Edward Island, Canada and Long Island, NY.

Two hundred growers will have attended a field day session (on-station or on-farm) in the two states and learned about WC and/or HGMs crop production opportunities by December 2013. Of these, 40 growers will have planted WC or HGMs by October 2014. Of these, 25 growers will document reduced pest populations, increased yields, and improved profitability.

So from the data above, one can see we accomplished our goals of introducing WC and HGM to growers in the region. We did not achieve the latter part of the goal due to the fact that neither WC nor fall planted HGM appear to be effective. We know of only 3 growers that tried winter canola during the project period with 2 stands falling from winter kill and one stand surviving for harvest. The harvested stand was located in Willsboro, NY.

• Image 1. Areas of excellent WC production
• Image 2. Areas of poor production
• Image 3. Icy patch in field – Stillwater Maine
• Image 4. Subsequent dead winter canola – Stillwater Maine – May 2014
• Table 2. Planting Date and Seeding Rate effect on survival and yield – Maine and Vermont
• Table 7. Black bean yield and disease severity by HGM incorporation. Alburg, VT.
• Example Winter Canola Research Reports
• Figure 1. Winter canola yield by variety – Stillwater Maine 2013
• Table 8. Educational outreach from SARE funded WC/HGM project
• Example winter canola research reports
• Table 3. Soil management effect on survival and yield – Maine and Vermont
• Table 5. All data from the On-Station Trial – Stillwater, ME
• Figure 2. Winter canola yield and survival of seventeen varieties in Vermont 2013-2014
• Table 1. Survival by variety – Maine and Vermont
• Table 4. Average yields of cover crops across Vermont and Maine farms and planting dates in Maine 2012 and 2013