Sunflower Chronicles: Part 3 – "Sunsetting Sunflowers for 2023"
As we sunset our sunflower viability trial for 2023, it's time we look back on what we have learned earlier in the year and the knowledge gained since the previous article. Early on, we saw good plant health with minimal initial damage. Later in the Summer, after herbicide application, the primary issue we saw was smooth pigweed. With no herbicide options for control, it took over most of the uncovered ground space. However, we still saw good plant health even with the weed infestation. Finally, we've come to the end of the trial, final management, and harvest.
Pigweed infestation in Sunflower trial. Note amount of weeds present in row.
Evaluation Factors
Throughout the end of the Sunflower season, we've continued to evaluate plant health and condition for several factors.
First, insect damage to seed did not climb to any notable levels. Less than 5% of plants showed insect damage, most of which was limited to the seeds on the edge of the heads. At harvest, some grasshoppers and moths were present, but at low levels that presented little concern.
Second, disease was a notable issue due to damp conditions throughout October. Primarily, we saw head rot from an unidentified source. The head rot made some of the heads less harvestable and contributed to some difficulty in cleaning unwanted plant material out of the final product. However, this was still a low enough level that any issues seen did not have much impact on overall production. Furthermore, strong test weight at harvest implies that it did not impact the seed quality.
Third, vertebrate damage did not pass the expected levels. Less than 5% of sunflower heads had bird damage, while deer damage did not pass expected levels (i.e., areas easily accessible from surrounding woodland had high levels of damage, but it stopped roughly 12 rows into the field). Overall, the final plant condition was favorable regardless of weather conditions and pests leading up to harvest.
Before harvest, the death and dry down of the sunflowers was partially a concern. Initial projections for the harvest of this trial were for early October. Due to the lack of killing frost before October 25th, plant death took longer than expected. Following the frost, the plants and seeds lost moisture rapidly, falling from 15% moisture to 8%, on average, within ten days. Moisture levels were surprising as we expected to harvest at higher moisture and use mechanical means to dry. While target moisture for harvest can be approximately 13%, as a method of lowering amounts of seed shatter, for operations with no way of drying the seed down, the lower the moisture the better. This is especially impactful as recommended storage moisture is a maximum of 10%. Of any factor at harvest, this was one of the most encouraging to viability as the cost point for drying could be high if multiple percentage points of moisture need to be removed.
Viability Factors
As we moved into harvest, production was expected to be low due to low population, with potential further reduction due to non-specialized harvest equipment. There were several important factors regarding viability to be considered as part of the harvest of this trial.
First, header issues impacted loss significantly. A grain platform head and a row crop head were used to ensure both standard options were considered. The grain platform, while good at ensuring less seed shatter and better removal of the Sunflower head, tended to have issues with feeding the product into the machine and caught sunflowers with the reel and ejected them in a forward manner that left them un-harvestable. The row crop head had fewer issues feeding harvested material but more significant problems with seed shatter.
Second, the presence of plant material in the final product was higher than expected. There were differing results based on which head was used, with the grain head leaving more material than the row head.
Finally, what did we yield? The final yield for this trial was roughly 150 bushels or about 3200 lbs. This would result in an approximate rate of 230 pounds/acre, which compared to standard target yield of 2000 pounds/acre, is very poor. Again, the primary limiting factor here was the initial population. Yield data here could be more helpful in considering actual production under optimal conditions. The other limiting factor for yield was the amount of product left behind in the field. Estimates of missed material ranged from 25 to 50 percent left behind or lost. Harvest may have been the most challenging part of this trial, but should the population issue be solved, it will likely be less problematic.
Low population of Sunflower Trial. Note distance between plants.
Highlights and Changes
So, what are the highlights, and what do we need to change to make this a viable opportunity?
Let's first review the most significant issues. First, population caused the most problems of any factor. The 20,000 seeds/acre rate was far too low for the Pennsylvania climate. While it is the average rate for traditional sunflower production areas, like the Dakotas, our climate allows us to use a much higher rate to improve overall stand health. At a minimum, the rate needs to be pushed to 30,000 seeds/acre. An optimal population is likely even higher. If we correct this issue, we should see a drastic increase in yield and a reduction in issues like harvestability and weed control.
Second, weed control. Weed presence in this trial has been the second most impactful issue after population. While our 30-inch rows did allow for easier management, they also prohibited any canopy from forming and provided a wealth of available space for weeds. A lack of selection for post-emergence herbicides further inhibits this. That lack leads to the conclusion that if we are to remain on 30-inch rows, cultivation or some other mechanical control is required to ensure weeds do not hamper plant growth. With 15-inch rows, we remove the ability to use mechanical control, but we should see the canopy providing additional assistance with weed control.
Third, header equipment. Header equipment is the other limiting factor that is currently appearing. Part of this is likely solvable with the correction of the population levels. However, it is also probable that adding sunflower pans to a grain platform or knife rolls to a row head would help to reduce loss from those platforms. Purchasing a specialty header would be the best option, but it is also cost-prohibitive for smaller operations.
Loss from Grain Platform head use.
Positives
Finally, the positives from this trial! First, plant health overall held up across the trial. No significant disease or pest damage was noted in any season. Occasional issues were noted, such as the presence of head rot at the end of the trial, but it did not occur in significant volume.
Second, the dry-down was far better than expected. We expected that we would have to harvest and then dry the sunflower seed due to higher moisture levels than in traditional sunflower production areas. However, moisture levels fell rapidly after frost to optimal storage levels of around 8%. That level of moisture loss is encouraging as we should have less cost associated, as there is less need for mechanical means of drying. However, does this mean that we have a viable crop for Western Pennsylvania?
Conclusions
Based solely on the results of this trial, we can't conclusively say whether sunflowers are a viable alternative crop. However, we have seen encouraging factors like solid plant health and no more than expected damage from pests. Also, by increasing population, we should see an improvement in many of the issues noted.
Final verdict? There's a good chance that sunflowers can be a viable crop. If we take what we've learned not to do from this trial and apply it, we should see more viability. Moving forward, keep an eye out for new trials as we continue exploring sunflowers as an alternative crop.
