Year 1 in the books.
Happy New Year All! My apologies for such a delayed update on the conclusion to the 2016 season. Our last harvest for the year was conducted on November 20, the week of Thanksgiving. This resulted in 19 consecutive weeks of harvesting.
Yield & Pest Challenges
Our plants yielded an average of 9,801 lbs of marketable fruit per acre (based on beds 5’ apart, plant spacing of 16" in row, and double rows/bed 12” apart). This yield is double what New England growers reported producing to the USDA in 2014. However, it is much lower than we expected for a day-neutral variety, as we should be producing about 15-25,000 lbs/acre using a plasticulture system.
This was almost certainly due to the fact that we experienced a significant Oriental Beetle grub infestation in August that caused serious damage to the root systems of plants and stunted many plants visually. We believe it also stunted the fruit size, as many of the stunted plants were not producing normally sized fruit. We sure hope we don't encounter this pest challenge again next year.
Effects of Low Tunnels on the Percent of Marketable Fruit
In 2016 we found that plots covered with a low tunnel produced a significantly higher percentage of marketable fruit (~85%) than the uncovered plots on black plastic and bare-ground (70-73%). Uncovered plots on white plastic did not produce a statistically lower percentage of marketable fruit than the covered plots, but at 77% it was lower, suggesting there is certainly a trend with all uncovered plants producing less marketable fruit. Other studies with low tunnels and day-neutral strawberry cultivars find that the low tunnels increase yield and the average fruit size over uncovered production. While we did find this in 2016, possibly due to our compromised plants, we are interested in what we will find in 2017.
Effects of Mulch Color on Yield
During four of the 19 week season, white-on-black plastic and black plastic produced significantly higher yields than the bare-ground raised beds. This period occured from the last week of August through late September (which was the highest yielding period of the season). However, this was the only period where these plastics produced more, and when total yields were compared, no differences in yield existed among the plastics. I suspect we may find different results next year when our plants are not highly compromised.
One of our most striking findings was the number of runners produced per plant. Strawberry plants on black plastic without a low tunnel cover produced an average of 10.3 runners per plant total during the season, significantly more than ALL other mulch / cover treatments which ranged from 3.2-5.1 runners per plant total.
Other Data & Thoughts
We have a plethora of temperature, sugar content, and storability data to get through and make sense of. This is high up on our to-do list, and we hope to get to the temperature data ASAP so we can begin to understand the way covers change temperature in the tunnels. A very brief look at this data showed this will be an undertaking, as many of the plastics effect the temperature differently depending on the time of the year.
It's also worth mentioning that we decided NOT to over winter this field of strawberry plants. The Oriental Beetle grubs re-emerge in the spring and resume feeding on plant roots. With plants already so stunted and poorly performing, we did not feel it was worth the effort or the spring yields would be representative of what they should be. However, we hope to overwinter 2017's crop into the spring of 2018.
As we start planning for the upcoming season, we will be making some minor changes to the project, notably by adding a 1.5mil cover treatment in addition to the four 6mil covers. If you are considering trying some day-neutrals, we recommend getting your orders in ASAP. A target planting date in April sets you up great for the 2017 season. Though, if we have a wet spring, an early May planting date may be where we are all at.
We will be sharing results and will be available for discussion at the NH Farm and Forest Expo on Saturday, February 18, 2017 during the New Hampshire Vegetable & Berry Growers Association Annual Meeting (9am - 3pm).
Kaitlyn will also be at the UNH Ag. Experiment Station booth in the trade show from 3-4:30 on Saturday, February 18.
Stay tuned for more updates and visit the Sideman Lab website to learn about other projects we are working on! This project is funded by the New Hampshire Agricultural Experiment Station and Tunnel Berries, a USDA National Institute of Food and Agriculture Specialty Crops Research Initiative grant titled "Optimizing Protected Culture for Berry Crops" in collaboration with the following universities: