Final report for LNE20-395
Project Information
Recommendations for fall nitrogen application in annual strawberry plasticulture are based on tradition and calendar date, however, these decisions are more appropriately based on the floral status of plants in production. Pre-plant N normally applied in plasticulture strawberries is unnecessary: it does not improve yield. However, targeted weekly applications of N for 3 consecutive weeks starting one week after floral initiation begins in the fall significantly enhances subsequent yield. Growers fertilize with N based on tradition and calendar date without any knowledge of the floral status of their plants. Flower mapping is used to to evaluate a plants floral status. While widely used in Europe, flower mapping is not used by US growers. We taught growers to flower map by providing a digital microscope, dissecting tools and video instructions.
Strawberry growers did not adopt the practice of flower mapping. It is a tedious and moderately difficult task which requires significant patience and time commitment. While most growers certainly have patience (waiting is a key part of agriculture) and commitment, flower mapping is better suited as a service based activity which would provide growers with the information they need. While delaying nitrogen application does not always lead to enhanced flowering and fruiting, a trend for such was detected in the yield trials of this study.
Based on this project and information gleaned from the literature and other studies conducted at Rutgers, we recommend that growers delay fall nitrogen application until several weeks after planting or a week or so after flower bud initiation is detected, whichever is suitable for a specific growers circumstances. The time of floral initiation would only be known to growers who flower maps. Unfortunately, there are no flower mapping services in the US. Even without knowledge of the floral status of their plugs at planting, growers should delay nitrogen application until several weeks after planting in the event that their plugs are still vegetative at planting. If plugs are vegetative at planting, nitrogen application can delay and reduce flower bud initiation. Since plugs are normally planted in late August / early September and floral initiation naturally occurs in mid-September, waiting several weeks will likely delay nitrogen application until floral initiation has occurred, thus preventing the possible inhibition of initiation which might occur with early nitrogen application. In other words, applying nitrogen at planting may be detrimental to floral initiation while delaying application may enhance floral initiation, and at the very least would not have any apparent detrimental side effects.
Science-based decisions using flower mapping will replace tradition and calendar based recommendations for N fertilization and row cover management to increase grower confidence and reduce stress with enhanced yields of 1,000 lbs per acre on at least one acre per farm on seventy-five farms in the Northeast.
Annual plasticulture (AP) is replacing the traditional matted row (MR) as the production system of choice for many growers in the temperate zone including many of the 3000+ strawberry growers in the Northeast. Successful AP requires critical decisions regarding cultivar selection, planting date and fall nitrogen fertilization. Cultivar and planting date choices are often location and market driven. Fall nitrogen fertilization is based on tradition or calendar date but should be based on a plant’s floral status. AP strawberries are provided 60 lbs pre-plant N per acre, yet pre-plant N does not improve monthly or total yield and over application of N leads to groundwater contamination especially on sandy soils. Thirty-seven percent of the total nitrogen load in estuaries of the Mid-Atlantic and Northeast US comes from agricultural activities and the pollution risk associated with N from strawberry production is among the highest reported risk levels. While pre-plant N does not improve yield, targeted weekly pulses of N for 3 consecutive weeks beginning one week after floral initiation is detected enhances yield by as much as 350 to 500%. The timing of the N pulses is critical as N application before floral initiation reduces yield and application too long after the start of floral initiation has no effect.
Nitrogen management in strawberry production should be based on plant floral status rather than tradition or calendar date. Floral status is easily determined using flower mapping which describes the position and fate (vegetative or floral) of meristems (buds) on a plant. Each meristem is evaluated via dissection under a stereoscope and identified as a vegetative or floral bud, a stolon or a branch crown with either a vegetative or floral apex and flower mapped plants are often depicted with simple drawings which reflect the status of each meristem on the plant.
The usefulness of flower mapping in European strawberry production is well documented and growers pay $5.00 (USD) to $50.00 per plant to estimate plant quality with respect to production potential. By knowing the floral quality of plants, adjustments to field production practices such as nitrogen fertilization can be made which enhance production. The information used by European growers is not directly transferable to US production since European systems are very different from those of the US regarding nearly every aspect of production (cultivars, field vs greenhouse production, time of planting, type of transplant used, etc.). The usefulness of flower mapping for North American production has not been described even though flower mapping is not difficult to perform and growers could easily learn the technique.
We attempted to teach growers how to flower map to provide a powerful tool for improving strawberry production. We invited ~2500 growers in the Northeast to participate in flower mapping workshops, originally proposed for regional grower meetings. Due to the COVID pandemic, in-person training was changed to online video training. Of the 2500+ growers invited, less than 50 participated in the workshops.
One grower summed up what we had hoped all growers would appreciate about the project: “This sounds like a great opportunity to actually learn when we should be applying fertilizer to our strawberries. If we had the tools and knowledge to make an informed decision that would be great. We currently use the multiple guess approach with timing and rate.... probably not the best!”. Other growers commented: “I think this is a great idea.”, “…a great technique to learn...we would employ it … in a heartbeat”, “this sounds like a great idea”, “I think this sounds like a fascinating idea and a long time coming”, “Thanks in advance for pursuing such a cool project”, “I think it's a great research project with great potential for improving strawberry management decisions. I hope--for many folks' sake--that you get funded.” In addition, presentations on strawberry flowering at the North American Strawberry Growers Association meeting (New Orleans, 2018), the Middle America Strawberry Growers Association Meeting (Branson, 2018), the Mid-Atlantic Fruit and Vegetable Growers Association Convention (Hershey, 2019) and the New Jersey Agricultural Convention and Trade Show (Atlantic City, 2019) generated significant interest in flower mapping.
We provided growers with the equipment to perform on-farm flower mapping as well as access to online video instuction for flower mapping technique. We aslo provided assistance whenever requested to help growers learn ho to flower map. We had hoped that by providing instruction, equipment and post-workshop support, we would build grower confidence and encourage adoption of this simple management tool to enhance strawberry production in the northeast. Unfortunately this did not occur, most likely due to the lack of diret one-on-one, in-person instruction which I think would have greatly enhanced the learning process.
Cooperators
- (Educator and Researcher)
Research
Flower mapping is a tool for strawberry growers to target pulses of N in the fall to enhance flowering and fruiting in the annual plasticulture system. Flower maps will remove the uncertainty regarding the effectiveness of current practices involving fall N fertilization and replace it with farm-generated, science-based recommendations to maximize sustainable strawberry production in the northeast.
The research component of this project had two goals (1) to establish, document and demonstrate the clear relationship between floral status and productivity in strawberry and (2) to demonstrate that plant floral status can be modified with N based on floral maps. Both goals were addressed with field studies repeated at two locations for three years. Flower maps were developed in the fall for the short-day cultivar ‘Chandler’ growing in the annual plasticulture system. Modification of plant floral status via N treatments was assessed from September through December each year of the study. Research was conducted at Rutgers Fruit and Ornamental Research Center in Cream Ridge, NJ and duplicated at The Clifford E. & Melda C. Snyder Research and Extension Farm - Rutgers Center for Sustainable Agriculture in Pittstown, NJ.
Two variations of the annual plasticulture system were utilized for the evaluation. One variation (the short day system) was the traditional annual plasticulture system using the short-day cultivar ‘Chandler’ which is familiar to growers. The other variation (the long-day system) utilized the long day cultivar ‘Albion’ in a fall, off-season system that is becoming increasingly popular in the northeast. The experimental designs were separate randomized complete blocks of each variation at each location in each year with 3-5 replications. All data was tested for normality, and the aligned rank transformation utilized for non-normal variables. All data was analyzed using an analysis of variance and means separated using Fishers Protected LSD.
Year One (2020)
Short-day System Using 'Chandler'
Plug plants of ‘Chandler’ were purchased from a commercial nursery in New Jersey. Plugs were planted in the plasticulture system on 9 September 2020 at Cream Ridge and 28 August at Snyder Farm. By 23 September 2020, approximately 50% of the plants at each location had died from Rhizoctonia and Thielaviopsis root rots. Nitrogen evaluation treatments were: (1) N0 (control, 0 ppm nitrogen), (2) N1 (800 ppm N one week after floral initiation detected) and (3) N2 (800 ppm N one week after floral initiation + 800 ppm N two weeks after floral initiation). The study at Snyder Farm had 5 replications while the one at Cream Ridge had 3 replications. Samples for floral mapping were taken from each site on the dates indicated in Table 1.
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Table 1. Planting, sampling and treatment dates for floral mapping study of ‘Chandler’ strawberry established in a plasticulture system at two sites in New Jersey. |
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Location |
|
|
Date |
Cream Ridge |
Snyder Farm |
|
Planting date |
9 September 2020 |
28 August 2020 |
|
Flower mapping |
10, 15, 21, 28 September |
|
|
|
5, 14, 19, 27 October |
15, 22, 30 October |
|
|
2, 11, 19 November |
6, 13, 20 November |
|
Nitrogen treatment 1 (N1) |
10/21 |
10/22 |
|
Nitrogen treatment 2 (N2) |
10/21 + 10/27 |
10/22 + 11/4 |
|
Row cover installation |
10 December |
14 December |
On each date listed for flower mapping in Table 1, five (Snyder Farm) or six (Cream Ridge) single plant samples from each site were taken from each nitrogen treatment and flower mapped. Flower mapping consisted of evaluating the terminal meristem and determining whether it was floral or vegetative via dissection using a digital microscope. The status of the terminal meristem was assigned 0 if vegetative and 1 if floral. If the meristem was floral, the floral stage was further categorized based on which flowers of the inflorescence were discernable at dissection: primary only = stage 1, secondary = stage 2, tertiary = stage 3 and quaternary or greater as stage 4. Axillary bud status was also evaluated for all buds subtending a live leaf. Buds were categorized as vegetative (0), runner (2) or branch crown. If a branch crown was present, the floral status of its terminal meristem was evaluated and categorized using the same criteria used for evaluating the terminal meristem of the main crown.
Data for flower mapping were evaluated separately for the two sites. A non-parametric analysis of data utilizing the Wilcoxon option in PROC NPAR1WAY test of the SAS® system which utilizes the Kruskal-Wallis test was used to evaluate differences in bud status and stage among the three treatments. Evaluations were performed for each meristem position on the main crown, beginning with the terminal position and progressing basipetally along the main crown.
Evaluation of plant architecture was performed in spring 2021 to evaluate effects of fall applied nitrogen on ‘Chandler’ growth and yield. Five plants per treatment were sampled from Snyder farm plots and fifteen plants per treatment from Cream Ridge plots and plant architecture assessed via dissection. Crown, leaf, inflorescence, flower and runner numbers per plant were determined. In addition, leaf, inflorescence, flower and runner production per crown were also evaluated. Fruit were harvested biweekly from 30 plants per treatment, total yield per plant determined then evaluated for nitrogen effects on productivity.
Data from each site were evaluated separately using a non-parametric analysis utilizing the Wilcoxon option in PROC NPAR1WAY test of the SAS® system which utilizes the Kruskal-Wallis test to evaluate differences in plant architectural features among the three treatments.
Long-day System Using 'Albion'
The long-day system was evaluated at one site only (Cream Ridge). Plug plants were propagated at the Cream Ridge Center using runner tips collected from mother plants established in coco coir bags on 29 June 2020 set atop raised beds covered with black plastic mulch. Mother plants were fertilized weekly with 60 ppm N obtained from Peters 20-20-20 soluble fertilizer supplied through trickle irrigation via an E-Z flo injector. Tips were harvested beginning 17 August 2020. Tips were set into 50-cell trays containing Pro Mix Organic mix. Tips were misted for 15 minutes every 60 minutes for 2 weeks until roots were established. Conditioning treatment of ‘Albion’ plugs was initiated on 9 September 2020. Conditioning consisted of a 2 x 2 factorial combination of photoperiod and nitrogen treatment. Photoperiod treatments were (1) natural daylength (SD) or (2) natural daylength supplemented with 15 minutes of incandescent radiation (C9, 7 watt bulbs (Novelty Lights, Inc., Centennial, CO) suspended 15 cm above the plant canopy) every hour from 7 pm until 7 am for two consecutive weeks (LD). Nitrogen treatment consisted of 0 or 800 ppm N during the second week of long day exposure. Plants were fertilized with Peters Soluble Fertilizer (20% available N, 20% available P2O5, 20% available K2O) diluted with water to provide 800 ppm N. Plants received enough solution to saturate the soil. The 0 ppm N treatment received no supplemental fertilization.
After conditioning, plugs were established in a plasticulture field planting at Rutgers Cream Ridge Research Farm. Plants were established on raised beds (20 cm high x 90 cm wide) covered with white on black (1 mil) plastic mulch with the white side exposed. There were two staggered rows per bed with 30 cm between rows and 38 cm between plants in the row. Irrigation was provided as needed via drip tape (10 Mil Medium Weight 5/8" AquaTraxx Drip Tape, 12” spacing, flow rate 0.45, The Toro Company, Bloomington, MN) placed in the center of the bed underneath the plastic mulch. Gothic Pro high tunnels (Farmers Friend, LLC) were erected over the plasticulture field. Three tunnels were erected. Each tunnel enclosed 2 adjacent beds. Each bed was a replicate with the 4 conditioning treatments randomly arranged in 20 plant plots to provide 4 treatment plots per bed. There were a total of 6 replicates (2 per tunnel) in the experiment.
On each date listed for flower mapping in Table 2, six single plant samples from each treatment were flower mapped. One plant was sampled from each treatment in each replicate. Flower mapping consisted of evaluating the terminal meristem and determining whether it was floral or vegetative via dissection using a digital microscope. The status of the terminal meristem was assigned 0 or vegetative and 1 if floral. If the meristem was floral, the floral stage was categorized based on which flowers of the inflorescence were discernable at dissection: primary only = stage 1, secondary = stage 2, tertiary = stage 3 and quaternary or greater as stage 4. Axillary bud status was not evaluated.
To increase statistical sample size, dates were combined as follows: 28 September, 5 October and 14 October combined as ‘Early Fall’ and 19 October, 27 October and 2 November combined as ‘Late Fall’. Data for flower mapping were evaluated using a non-parametric analysis of data utilizing the Wilcoxon option in PROC NPAR1WAY test of the SAS® system which utilizes the Kruskal-Wallis test to evaluate differences in bud status and stage among the four treatments.
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Table 2. Planting, sampling and treatment dates for floral mapping study of ‘Albion’ strawberry established in a high tunnel plasticulture system at Rutgers Cream Ridge Research Center, Cream Ridge, New Jersey. |
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|
Activity |
Date |
|
Mother plant establishment |
29 June 2020 |
|
Runner tip harvest |
17 August 2020 |
|
Conditioning treatment initiated |
16 September 2020 |
|
Field planting date |
5 October 2020 |
|
Flower mapping |
21, 28 September |
|
|
5, 14, 19, 27 October |
|
|
2 November |
The planting was established too late to produce a fall crop. Yield was evaluated in the spring of 2021 for plants conditioned in the fall of 2020.
Year Two (2021)
Short-day System Using 'Chandler'
Plug plants of ‘Chandler’ were propagated from runner tips purchased from a commercial nursery in New Jersey and planted in the plasticulture system on 20 September 2021 at Cream Ridge and 9 September at Snyder Farm. The experimental plan for ‘Chandler’ in 2021 included four treatments: (1) Control (0 lbs N/acre), (2) 30 lbs N/acre one week after planting, (3) 60 lbs N/acre one week after planting and (4) 60 lbs N one week after flower initiation was observed. Planting, flower mapping, row cover installation and treatment dates are presented for both locations in Table 3.
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Table 3. Planting, sampling and treatment dates for floral mapping study of ‘Chandler’ strawberry established in a plasticulture system at two sites in New Jersey. |
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|
|
Location |
|
|
Date |
Cream Ridge |
Snyder Farm |
|
Planting date |
20 September 2021 |
9 September 2021 |
|
Flower mapping |
8, 21, 28 September |
8, 21 September |
|
|
7, 14, 20, 28 October |
14, 25 October |
|
Nitrogen treatment 1 (30) |
9/28 |
9/16 |
|
Nitrogen treatment 2 (60) |
9/28 |
9/16 |
|
Nitrogen treatment 3 (Floral 60) |
10/28 |
10/21 |
|
Row cover installation |
12/2 |
11/18 |
On each date listed for flower mapping in Table 3, five (Snyder Farm) or six (Cream Ridge) single plant samples from each site were taken from each nitrogen treatment and flower mapped. Flower mapping consisted of evaluating the terminal meristem and determining the floral or vegetative status via dissection using a digital microscope. The status of the terminal meristem was assigned 0 if vegetative and 1 to 4 if floral, depending on which flowers of the inflorescence were discernable at dissection: primary only = 1, secondary = 2, tertiary = 3 and quaternary or greater = 4.
Data for flower mapping were evaluated separately for the two sites. A non-parametric analysis of data utilizing the Wilcoxon option in PROC NPAR1WAY test of the SAS® system which utilizes the Kruskal-Wallis test was used to evaluate differences in bud status among the three treatments.
Evaluation of plant architecture was performed in spring 2022 to evaluate effects of fall applied nitrogen on growth and yield. Five plants per treatment were sampled from Snyder farm plots and fifteen plants per treatment from Cream Ridge plots and plant architecture assessed via dissection. Crown, linflorescence and flower numbers per plant were determined. In addition, leaf, inflorescence, flower and runner production per crown were also evaluated.
Data from each site were evaluated separately using a non-parametric analysis utilizing the Wilcoxon option in PROC NPAR1WAY test of the SAS® system which utilizes the Kruskal-Wallis test to evaluate differences in plant architectural features among the three treatments.
Long day system using 'Albion'
This study was conducted only at Cream Ridge. Plug plants were propagated from runner tips from a commercial nursery in Canada beginning August 17, 2021. Plugs were conditioned with treatments consisting of a 2 x 2 factorial combination of photoperiod and nitrogen treatment. Photoperiod treatments were (1) natural daylength (SD) or (2) natural daylength supplemented with 15 minutes of incandescent radiation (C9, 7 watt bulbs (Novelty Lights, Inc., Centennial, CO) suspended 15 cm above the plant canopy) every hour from 7 pm until 7 am for two consecutive weeks (LD). Nitrogen treatment consisted of 0 or 800 ppm N during the second week of long day exposure. Plants were fertilized with Peters Soluble Fertilizer (20% available N, 20% available P2O5, 20% available K2O) diluted with water to provide 800 ppm N. Plants received enough solution to saturate the soil. The 0 ppm N treatment received no supplemental fertilization. After conditioning, plugs were established in a plasticulture field planting at Rutgers Cream Ridge Research Farm. Plants were established on raised beds (20 cm high x 90 cm wide) covered with white on black (1 mil) plastic mulch with the white side exposed. There were two staggered rows per bed with 30 cm between rows and 38 cm between plants in the row. Irrigation was provided as needed via drip tape (10 Mil Medium Weight 5/8" AquaTraxx Drip Tape, 12” spacing, flow rate 0.45, The Toro Company, Bloomington, MN) placed in the center of the bed underneath the plastic mulch. Gothic Pro high tunnels (Farmers Friend, LLC) were erected over the plasticulture field. Five tunnels were erected. Each tunnel enclosed 2 adjacent beds. Each bed was a replicate with the 4 conditioning treatments randomly arranged in 20 plant plots to provide 4 treatment plots per bed. There were a total of 10 replicates (2 per tunnel) in the experiment.
Fruit were harvested, counted and weighed in Spring 2023 and evaluated for a conditioning effect.
Year Three (2022)
Short-day System Using 'Chandler'
Plug plants of ‘Chandler’ were propagated from runner tips purchased from a commercial nursery in New Jersey for establishing in field plantings at Cream Ridge and Snyder Farm for flower mapping studies. Plugs were planted in the plasticulture system on 12 September 2022 at Cream Ridge and 26 August at Snyder Farm. The experimental plan for ‘Chandler’ in 2022 included three treatments: (1) Control (0 lbs N/acre), (2) 60 lbs N/acre one week after planting, and (3) 60 lbs N/acre one week after flower initiation was observed. Planting, flower mapping, row cover installation and treatment dates are presented for both locations in Table 4.
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Table 4. Planting, sampling and treatment dates for floral mapping study of ‘Chandler’ strawberry established in a plasticulture system at two sites in New Jersey. |
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Location |
|
|
Date |
Cream Ridge |
Snyder Farm |
|
Planting date |
12 September | 26 August |
|
Flower mapping |
13, 19, 28 September | 28 Sptember |
|
|
6 October | 12, 28 October |
|
|
1 November | |
|
Nitrogen treatment 1 (60 at planting) |
19 September | 15 September |
|
Nitrogen treatment 2 (60 when floral) |
14 October | 2 November |
|
Row cover installation |
29 November | 21 November |
On each date listed for flower mapping in Table 4, five (Snyder Farm) or six (Cream Ridge) single plant samples from each site were taken from each nitrogen treatment and flower mapped. Flower mapping consisted of evaluating the terminal meristem and determining the floral or vegetative status via dissection using a digital microscope. The status of the terminal meristem was assigned 0 if vegetative and 1 to 4 if floral, depending on which flowers of the inflorescence were discernable at dissection: primary only = 1, secondary = 2, tertiary = 3 and quaternary or greater = 4.
Data for flower mapping were evaluated separately for the two sites. A non-parametric analysis of data utilizing the Wilcoxon option in PROC NPAR1WAY test of the SAS® system which utilizes the Kruskal-Wallis test was used to evaluate differences in bud status among the three treatments. Results are presented in the section labelled ‘Results and Discussion’.
Fruit were harvested, counted and weighed at both locations in Spring 2023. Fruit were havested from 12 May 2023 thru 20 June 2023 at Cream Ridge and 19 May 2023 thru 19 June 2023 at Snyder Farm.
Year One (2020)
Short-day System Using 'Chandler'
Chandler Flower Mapping - Cream Ridge Location
No nitrogen fertilization effects on terminal bud status was detected. Floral initiation was first observed on 14 October. By 27 October, all terminal meristems were floral. Nitrogen fertilization enhanced floral stage of terminal meristems. On 2 November two applications of nitrogen significantly enhanced floral development compared to one nitrogen application which significantly advanced floral development compared to controls (Table 5). On 11 November, both nitrogen treatments significantly enhanced floral development compared to controls. By 19 November, all terminal meristems had fully developed floral meristems (stage 4).
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Table 5. Average status and floral stage of terminal meristems of ‘Chandler’ strawberry in a plasticulture system (Cream Ridge). Nitrogen treatments were administered as indicated. Status 0 = vegetative, 1 = floral; Stage 0 = vegetative, 1 = primary visible, 2 = secondary visible, 3 = tertiary visible, 4 = quaternary visible. |
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Terminal Mersitem Status |
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|
Treament |
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Date |
N0 |
N1 |
N2 |
|
9 September |
Planting |
||
|
10 September |
0.0 |
||
|
15 September |
0.0 |
||
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21 September |
0.0 |
||
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28 September |
0.0 |
||
|
5 October |
0.0 |
||
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14 October |
0.55 |
||
|
19 October |
0.78 |
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|
N1 Treatment |
|||
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27 October |
1.00 |
1.00 |
1.00 |
|
N2 Treatment |
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2 November |
1.00 |
1.00 |
1.00 |
|
11 November |
1.00 |
1.00 |
1.00 |
|
19 November |
1.00 |
1.00 |
1.00 |
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|
Terminal Mersitem Stage |
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|
Treament |
||
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Date |
N0 |
N1 |
N2 |
|
9 September |
Planting |
||
|
10 September |
0.0 |
||
|
15 September |
0.0 |
||
|
21 September |
0.0 |
||
|
28 September |
0.0 |
||
|
5 October |
0.0 |
||
|
14 October |
0.78 |
||
|
19 October |
1.22 |
||
|
N1 Treatment |
|||
|
27 October |
1.67 |
2.67 |
|
|
N2 Treatment |
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|
2 November |
1.83 c |
2.67 b |
3.67 a |
|
11 November |
3.00 b |
3.80 a |
3.83 a |
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19 November |
4.0 |
4.0 |
4.0 |
Axillary meristem development
No effects of nitrogen application on axillary bud development were detected via dissection on any of the dates sampled (Table 6). Some interesting observations regarding floral and branch crown development were made during evaluation of dissection data. By 27 October, all terminal meristems were floral and nearly all axillary meristems were vegetative, particularly those in positions 1 through 6 (96% vegetative). Runners were detected in positions 7 and 8 on 27 October. Axillary buds were 99% vegetative on 2 November (only positions 1 through 6 were dissected on this date). Between 2 and 11 November, considerable branch crown formation occurred and 98% of the branch crowns observed were vegetative. Considerable floral initiation occurred in branched crown terminal meristems between 11 and 19 November.
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Table 6. Axillary meristem development of ‘Chandler’ strawberry in a plasticulture system (Cream Ridge). Axillary meristems are labeled from apex to basal beginning with 1 as the meristem closest to the apex. Nitrogen treatments were administered as N1 (10/21) and N2 (10/21 + 10/27). Values are % of axillary meristems at that location exhibiting the listed characteristic. Values are based on 18 dissections per date. No nitrogen treatment effects were detected via dissections. |
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Date |
Axil |
Veg |
Runner |
Branch, veg |
Branch, floral |
|
27 October |
1 |
100 |
0 |
0 |
0 |
|
|
2 |
100 |
0 |
0 |
0 |
|
|
3 |
100 |
0 |
0 |
0 |
|
|
4 |
78 |
0 |
0 |
22 |
|
|
5 |
100 |
0 |
0 |
0 |
|
|
6 |
100 |
0 |
0 |
0 |
|
|
7 |
89 |
11 |
0 |
0 |
|
|
8 |
43 |
57 |
0 |
0 |
|
|
|
|
|
|
|
|
Date |
Axil |
Veg |
Runner |
Branch, veg |
Branch, floral |
|
2 November |
1 |
100 |
0 |
0 |
0 |
|
|
2 |
100 |
0 |
0 |
0 |
|
|
3 |
100 |
0 |
0 |
0 |
|
|
4 |
100 |
0 |
0 |
0 |
|
|
5 |
100 |
0 |
0 |
0 |
|
|
6z |
94 |
0 |
0 |
6 |
|
|
|
|
|
|
|
|
Date |
Axil |
Veg |
Runner |
Branch, veg |
Branch, floral |
|
11 November |
1 |
94 |
0 |
0 |
6 |
|
|
2 |
78 |
0 |
17 |
6 |
|
|
3 |
56 |
0 |
44 |
0 |
|
|
4 |
33 |
0 |
67 |
0 |
|
|
5 |
56 |
0 |
44 |
0 |
|
|
6 |
71 |
0 |
29 |
0 |
|
|
7 |
69 |
13 |
19 |
0 |
|
|
8 |
58 |
17 |
25 |
0 |
|
|
9 |
75 |
25 |
0 |
0 |
|
|
10 |
25 |
75 |
0 |
0 |
|
|
|
|
|
|
|
|
Date |
Axil |
Veg |
Runner |
Branch, veg |
Branch, floral |
|
19 November |
1 |
100 |
0 |
0 |
0 |
|
|
2 |
100 |
0 |
0 |
0 |
|
|
3 |
33 |
0 |
28 |
39 |
|
|
4 |
28 |
0 |
22 |
50 |
|
|
5 |
28 |
0 |
11 |
61 |
|
|
6 |
22 |
0 |
17 |
61 |
|
|
7 |
39 |
6 |
0 |
56 |
|
|
8 |
19 |
25 |
6 |
50 |
|
|
9 |
28 |
45 |
0 |
27 |
|
|
10 |
0 |
100 |
0 |
0 |
|
zOnly 6 axillary buds per plant dissected on this date. |
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Snyder Farm Location
No nitrogen effects on floral development were detected in samples from Snyder Farm (Table 7). Nearly all terminal meristems were floral on the first sampling date, which appeared to be too late to catch the transition from vegetative to floral.
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Table 7. Average status and floral stage of terminal meristems of ‘Chandler’ strawberry in a plasticulture system (Snyder Farm). Nitrogen treatments were administered as indicated. Status 0 = vegetative, 1 = floral; Stage 0 = vegetative, 1 = primary visible, 2 = secondary visible, 3 = tertiary visible, 4 = quaternary visible. |
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|
Terminal Mersitem Status |
||
|
|
Treament |
||
|
Date |
N0 |
N1 |
N2 |
|
28 August |
Planting |
||
|
15 October |
0.8 |
||
|
22 October |
1.0 |
||
|
N1 Treatment |
|||
|
30 October |
1.0 |
1.0 |
|
|
N2 Treatment |
|||
|
6 November |
1.0 |
1.0 |
1.0 |
|
13 November |
1.0 |
1.0 |
1.0 |
|
20 November |
1.0 |
1.0 |
1.0 |
|
|
Terminal Mersitem Stage |
||
|
|
Treament |
||
|
Date |
N0 |
N1 |
N2 |
|
28 August |
Planting |
||
|
15 October |
1.4 |
||
|
22 October |
2.1 |
||
|
N1 Treatment |
|||
|
30 October |
3.4 |
3.7 |
|
|
N2 Treatment |
|||
|
6 November |
4.0 |
4.0 |
3.6 |
|
13 November |
3.8 |
3.8 |
4.0 |
|
20 November |
3.4 |
4.0 |
4.0 |
The status of axillary meristems varied considerably across sample dates. The percentage of branch crowns which were floral rose from 13, 2 and 17% over the first three dates (22 and 30 October, 6 November) to 52 and 46% on the last two dates (13 and 20 November) (Table 8). No effects of nitrogen on bud development were detected through 20 November.
|
Table 8. Axillary meristem development of ‘Chandler’ strawberry in a plasticulture system (Snyder Farm). Axillary meristems are labeled from apex to basal beginning with 1 as the meristem closest to the apex. Nitrogen treatments were administered as N1 (10/22) and N2 (10/22 + 11/04). Values are % of axillary meristems at that location exhibiting the listed characteristic. Values are based on 15 dissections per date. No nitrogen treatment effects were detected via dissections. |
|||||
|
Date |
Axil |
Veg |
Runner |
Branch, veg |
Branch, floral |
|
22 October |
1 |
100 |
0 |
0 |
0 |
|
|
2 |
100 |
0 |
0 |
0 |
|
|
3 |
40 |
0 |
50 |
10 |
|
|
4 |
10 |
0 |
80 |
10 |
|
|
5 |
0 |
10 |
40 |
50 |
|
|
6 |
0 |
20 |
70 |
10 |
|
|
|
|
|
|
|
|
Date |
Axil |
Veg |
Runner |
Branch, veg |
Branch, floral |
|
30 October |
1 |
100 |
0 |
0 |
0 |
|
|
2 |
100 |
0 |
0 |
0 |
|
|
3 |
40 |
0 |
50 |
10 |
|
|
4 |
11 |
0 |
89 |
0 |
|
|
5 |
0 |
17 |
67 |
17 |
|
|
6 |
0 |
22 |
78 |
0 |
|
|
7 |
0 |
40 |
60 |
0 |
|
|
8 |
0 |
100 |
0 |
0 |
|
|
9 |
0 |
100 |
0 |
0 |
|
|
|
|
|
|
|
|
Date |
Axil |
Veg |
Runner |
Branch, veg |
Branch, floral |
|
6 November |
1 |
100 |
0 |
0 |
0 |
|
|
2 |
67 |
0 |
33 |
0 |
|
|
3 |
40 |
0 |
60 |
0 |
|
|
4 |
40 |
0 |
60 |
0 |
|
|
5 |
13 |
0 |
60 |
27 |
|
|
6 |
36 |
0 |
21 |
43 |
|
|
7 |
13 |
13 |
27 |
47 |
|
|
8 |
42 |
8 |
17 |
33 |
|
|
9 |
17 |
67 |
17 |
0 |
|
|
|
|
|
|
|
|
Date |
Axil |
Veg |
Runner |
Branch, veg |
Branch, floral |
|
13 November |
1 |
100 |
0 |
0 |
0 |
|
|
2 |
47 |
0 |
20 |
33 |
|
|
3 |
33 |
0 |
20 |
47 |
|
|
4 |
0 |
0 |
33 |
67 |
|
|
5 |
7 |
0 |
20 |
73 |
|
|
6 |
17 |
8 |
8 |
67 |
|
|
7 |
18 |
0 |
0 |
82 |
|
|
8 |
10 |
20 |
10 |
60 |
|
|
9 |
10 |
40 |
0 |
50 |
|
|
10 |
0 |
60 |
0 |
40 |
|
|
|
|
|
|
|
|
Date |
Axil |
Veg |
Runner |
Branch, veg |
Branch, floral |
|
20 November |
1 |
100 |
0 |
0 |
0 |
|
|
2 |
79 |
0 |
7 |
14 |
|
|
3 |
47 |
0 |
7 |
47 |
|
|
4 |
13 |
0 |
20 |
67 |
|
|
5 |
20 |
0 |
33 |
47 |
|
|
6 |
14 |
0 |
14 |
72 |
|
|
7 |
31 |
8 |
8 |
54 |
|
|
8 |
18 |
9 |
9 |
64 |
|
|
9 |
20 |
30 |
0 |
50 |
|
|
|||||
Long day system using 'Albion'
Conditioning of ‘Albion’ plugs was effective in enhancing floral initiation as determined by flower mapping (Table 9). In plants dissected in early fall, long days with a boost of nitrogen enhanced both terminal meristem status and floral stage (Table 9). By late fall, the effect of conditioning with long days or nitrogen were quite visible in dissections: long days or elevated nitrogen significantly induced a shift towards floral terminal meristems compared to natural daylength controls. Stage of terminal meristem development was significantly enhanced by combining long days with elevated nitrogen. While the singular effect of elevated nitrogen under natural daylength was not observed in early fall dissections, the effect of elevated nitrogen was clear in meristems dissected later in the fall. This is important for growers who want to enhance floral development but do not wish to use supplemental lighting strategies. The elevated nitrogen treatment is very easy to implement. Conditioning start date for plants in this study was not based on dissection data as initially planned. ‘Albion’ plants dissected from late summer through early fall showed no signs of floral initiation which was an unexpected anomaly. In previous years, ‘Albion’ initiates flowers from mid-August through the fall under natural field conditions. Plants used in this study were conditioned when in a vegetative state to try to induce flower formation. The original plan was to provide extra nitrogen after floral initiation was first observed in an attempt to enhance floral development, not to induce it. Nevertheless, our results this season suggest that the use of dissections to determine appropriate timing of conditioning for long day cultivars may not be needed. The results confirm the benefits to floral development due to conditioning with daylength or nitrogen.
|
Table 9. Average status and floral stage of terminal meristems of ‘Albion’ strawberry conditioned with photoperiod and elevated nitrogen. Conditioning occurred from 16 – 30 September. Status 0 = vegetative, 1 = floral; Stage 0 = vegetative, 1 = primary visible, 2 = secondary visible, 3 = tertiary visible, 4 = quaternary visible. |
|||
|
|
|
Photoperiod |
|
|
Date |
Nitrogen |
Short day |
Long day |
|
Early Fall |
|
Terminal meristem status |
|
|
|
0 |
0.17 b |
0.28 ab |
|
|
800 |
0.01 b |
0.44 a |
|
|
|
Terminal meristem floral stage |
|
|
|
0 |
0.28 b |
0.28 b |
|
|
800 |
0.06 b |
0.89 a |
|
Late Fall |
|
Terminal meristem status |
|
|
|
0 |
0.22 b |
0.71 a |
|
|
800 |
0.71 a |
0.88 a |
|
|
|
Terminal meristem floral stage |
|
|
|
0 |
0.44 c |
1.12 bc |
|
|
800 |
1.35 b |
2.16 a |
|
|
|||
Evaluation of Fall 2020 'Chandler' nitrogen treatment on Spring 2021 Flower Maps and Yield
Cream Ridge
No nitrogen effect on crown, leaf, inflorescence, flower or runner number per plant or leaf, flower or runner number per crown assessed via dissection in April 2021 was detected (Table 10). Average yield per plant was 516 g and was not affected by nitrogen treatment.
Snyder Farm
No nitrogen effect on crown, leaf, inflorescence, flower or runner number per plant or leaf or runner number per crown assessed via dissection in May 2021 was detected. Plants receiving fall nitrogen produced 1.4 additional flowers per crown compared to plants not receiving fall nitrogen (Table 10). Average yield per plant was 574 g and was not affected by nitrogen treatment, thus the additional flower per crown was not sufficient to enhance overall yield.
|
Table 10. Average plant status and yield of ‘Chandler’ strawberry in a plasticulture system at two sites in New Jersey (Cream Ridge Farm and Snyder Farm). Nitrogen treatments were administered in fall 2020. No treatment effects were detected, thus mean values over all treatments are presented. |
|||
|
Location and Date |
Attribute |
Mean value |
|
|
Cream Ridge 20 April 2021 |
Crowns·plant-1 |
4.8 |
|
|
|
Leaves·plant-1 |
17.3 |
|
|
|
Inflorescences·plant-1 |
4.8 |
|
|
|
Flowers·plant-1 |
38.2 |
|
|
|
Runners·plant-1 |
0.4 |
|
|
|
Leaves·crown-1 |
3.7 |
|
|
|
Flowers·crown-1 |
8.0 |
|
|
|
Runners·crown-1 |
0.1 |
|
|
|
Yield·plant-1(g) |
516 |
|
|
Snyder Farm 4 May 2021 |
Crowns·plant-1 |
8.1 |
|
|
|
Leaves·plant-1 |
24.8 |
|
|
|
Inflorescences·plant-1 |
8.1 |
|
|
|
Flowers·plant-1 |
62.7 |
|
|
|
Runners·plant-1 |
0.5 |
|
|
|
Leaves·crown-1 |
3.1 |
|
|
|
Flowers·crown-1 |
No Fall Nitrogen |
6.8 b |
|
|
|
Fall Nitrogen |
8.2 az |
|
|
Runners·crown-1 |
0.1 |
|
|
|
Yield·plant-1 |
574 |
|
|
zMean separation at α = 0.05 via planned F-test. |
|||
Evaluation of Fall 2020 'Albion' conditioning effects on Spring 2021 Yield
Conditioning with long-days enhanced the number of fruit produced in the spring per plant: Non-conditioned plants produced an average of 12 fruit per plant while conditioned plants produced and average of 14 fruit per plant. Weight of fruit produced was not influenced by conditioning: plants produced an average of 240 g from April through early June.
Year Two (2021)
Short-day System Using 'Chandler'
Chandler Flower Mapping Fall 2021
Cream Ridge Location
Floral initiation was observed on 21 October in samples from Cream Ridge (Table 11).
|
Table 11. Average status and floral stage of terminal meristems of ‘Chandler’ strawberry in a plasticulture system (Cream Ridge). Nitrogen treatments were administered as indicated. Status 0 = vegetative, 1 = floral; Stage 0 = vegetative, 1 = primary visible, 2 = secondary visible, 3 = tertiary visible, 4 = quaternary visible. |
|||||||
|
|
Terminal Mersitem Status |
||||||
|
|
Treatment |
||||||
|
Date |
N0 |
N30 |
N60 |
NFloral60 |
|||
|
8 September |
0.0 |
||||||
|
21 September |
0.0 |
||||||
|
28 September |
0.0 |
||||||
|
28 September |
N30 and N60 treatment application |
||||||
|
7 October |
0.0 |
0.0 |
0.0 |
-- |
|||
|
14 October |
0.1 |
0.0 |
0.0 |
-- |
|||
|
21 October |
1.4 |
2.6 |
2.0 |
2.0 |
|||
|
28 October |
NFloral 60 treatment application |
||||||
|
28 October |
2.6 |
1.8 |
2.6 |
2.2 |
|||
Snyder Farm Location
Floral initiation was observed on 14 October in samples from Snyder Farm (Table 12).
|
Table 12. Average status and floral stage of terminal meristems of ‘Chandler’ strawberry in a plasticulture system (Snyder Farm). Nitrogen treatments were administered as indicated. Status 0 = vegetative, 1 = floral; Stage 0 = vegetative, 1 = primary visible, 2 = secondary visible, 3 = tertiary visible, 4 = quaternary visible. |
|||||||
|
|
Terminal Mersitem Status |
||||||
|
|
Treatment |
||||||
|
Date |
N0 |
N30 |
N60 |
NFloral60 |
|||
|
8 September |
0.0 |
||||||
|
16 September |
N30 and N60 treatment application |
||||||
|
14 October |
0.5 |
0.8 |
0.8 |
-- |
|||
|
21 October |
NFloral 60 treatment application |
||||||
|
25 October |
2.8 |
2.0 |
2.4 |
2.8 |
|||
Evaluation of Fall 2021 'Chandler' nitrogen treatment on Spring 2022 Flower Maps and Yield
Plant samples from each treatment and each location were dissected on 4/26 (Cream Ridge) or 5/10 (Snyder Farm). Crown, inflorescence and flower production as well as yield for Snyder Farm are presented below (Table 13). The number of inflorescences per plant at Cream Ridge was enhanced with 60 lbs N/Acre at planting compared to 30 lbs N/Acre at planting (5.3 vs 3.8 inflorescences per plant for 30 and 60 lbs N/Acre, respectively). No other significant treatment effects were detected at Cream Ridge or Snyder Farm. Consecutive freezes on 17 and 18 April 2021 resulted in a complete crop failure at Cream Ridge.
|
Table 13. Average plant status and yield of ‘Chandler’ strawberry in a plasticulture system at two sites in New Jersey (Cream Ridge Farm and Snyder Farm). Nitrogen treatments were administered in fall 2021. No treatment effects were detected, thus mean values over all treatments are presented. |
|||
|
Location and Date |
Attribute |
Mean value |
|
|
Cream Ridge 26 April 2021 |
Crowns·plant-1 |
4.7 | |
|
|
Inflorescences·plant-1 |
4.5 | |
|
|
Flowers·plant-1 |
32.4 | |
|
|
Inflorescences·crown-1 |
0.9 | |
|
|
Flowers·inflorescence-1 |
5.8 | |
|
|
Yield·plant-1(g) |
0 | |
|
Snyder Farm 4 May 2021 |
Crowns·plant-1 |
4.8 | |
|
|
Inflorescences·plant-1 |
5.2 | |
|
|
Flowers·plant-1 |
33.7 | |
|
|
Inflorescences·crown-1 |
1.1 | |
|
|
Flowers·inflorescence-1 |
6.5 | |
|
Yield·plant-1(g) |
316 | ||
Evaluation of Fall 2021 'Albion' conditioning effects on Spring 2022 Yield
No effect of fall conditioning on yield of 'Albion' in Spring 2022 was detected. Average yield per plant from April through June was 160 g.
Year Three (2022)
Short-day System Using 'Chandler'
Chandler Flower Mapping Fall 2022
Cream Ridge Location
Floral initiation was observed between 28 September and 6 October in samples from Cream Ridge (Table 14). There was no significant effect of nitrogen treatments on status or stage of floral development.
|
Table 14. Average status and floral stage of terminal meristems of ‘Chandler’ strawberry in a plasticulture system (Cream Ridge). Nitrogen treatments were administered as indicated. Status 0 = vegetative, 1 = floral; Stage 0 = vegetative, 1 = primary visible, 2 = secondary visible, 3 = tertiary visible, 4 = quaternary visible. |
|||||||
|
|
Terminal Mersitem Status |
||||||
|
|
Treatment |
||||||
|
Date |
N0 |
|
N60 |
|
NFloral60 |
||
|
13 September |
0.0 |
||||||
|
19 September |
0.0 |
||||||
|
19 September |
N60 treatment application |
||||||
|
28 September |
0.0 |
0.0 |
- |
||||
|
6 October |
90% floral, Stage = 2.0 | 100% floral, Stage = 1.6 | - | ||||
|
14 Ocotober |
NFloral 60 treatment application | ||||||
|
1 November |
3.6 | 3.6 | 3.2 | ||||
Snyder Farm Location
Floral initiation was observed just after 12 October in samples from Snyder Farm (Table 15). While the N1 treatment had apices at a slightly more advanced stage in dissections compared to N0 and N2 on 28 October, the difference was not statistically significant.
|
Table 15. Average status and floral stage of terminal meristems of ‘Chandler’ strawberry in a plasticulture system (Snyder Farm). Nitrogen treatments were administered as indicated. Status 0 = vegetative, 1 = floral; Stage 0 = vegetative, 1 = primary visible, 2 = secondary visible, 3 = tertiary visible, 4 = quaternary visible. |
|||||||
|
|
Terminal Mersitem Status |
||||||
|
|
Treatment |
||||||
|
Date |
N0 |
N60 |
NFloral60 |
||||
|
2 September |
N60 treatment application |
||||||
|
28 September |
0.0 | 0.0 | - | ||||
|
12 October |
0.0 | 0.0 | - | ||||
|
19 October |
NFloral 60 treatment application |
||||||
|
28 October |
2.3 | 2.8 | 2.3 | ||||
Evaluation of Fall 2022 'Chandler' nitrogen treatment on Spring 2023 Fruit Yield
Snyder Farm
No significant treatment effect was detected for total marketable yield, culled fruit or crowns per plant. The average yield was 559 g with 30 g of culled fruit and 6 crowns per plant. A significant effect was detected for average fruit size. Fruit from plants receiving N either at planting or after flower bud initiation was detected were larger (14.5 g) than fruit from control plants (13.2 g). While statistically significant, the practical significance is minor.
Cream Ridge
Delaying N application until one week after floral initiation was detected enhanced yield and fruit number per plant when compared to providing nitrogen at planting (428 g, 41 fruit per plant and 336 g, 29 fruit, for floral and planting treatments, respectively). The yield difference between the control and floral treatment was not statistically significant at the 0.05 level, however, it was significant at the 0.10 level (368 g, 33 fruit per plant and 428 g, 41 fruit for control and floral treatments, respectively). The 60 gram per plant difference in yield translates to 1,982 lbs of additional fruit per acre with delayed fertilization, assuming a planting density of 15,000 plants per acre. The standard recommendation for strawberry plasticulture fertilization is 60 lbs N per acre applied pre-plant, which is the same as the ‘Planting’ treatment in this study. By delaying fertilization based on flower mapping, an additional 3039 lbs of fruit per acre was harvested.
Strawberry growers did not adopt the practice of flower mapping. It is a tedious and moderately difficult task which requires significant patience and time commitment. While most growers certainly have patience (waiting is a key part of agriculture) and commitment, flower mapping is better suited as a service based activity which would provide growers with the information they need. While delaying nitrogen application does not always lead to enhanced flowering and fruiting, a trend for such was detected in the yield trials of this study.
Based on this project and information gleaned from the literature and other studies conducted at Rutgers, we recommend that growers delay fall nitrogen application until several weeks after planting or a week or so after flower bud initiation is detected, whichever is suitable for a specific growers circumstances. The time of floral initiation would only be known to growers who flower maps. Unfortunately, there are no flower mapping services in the US. Even without knowledge of the floral status of their plugs at planting, growers should delay nitrogen application until several weeks after planting in the event that their plugs are still vegetative at planting. If plugs are vegetative at planting, nitrogen application can delay and reduce flower bud initiation. Since plugs are normally planted in late August / early September and floral initiation naturally occurs in mid-September, waiting several weeks will likely delay nitrogen application until floral initiation has occurred, thus preventing the possible inhibition of initiation which might occur with early nitrogen application. In other words, applying nitrogen at planting may be detrimental to floral initiation while delaying application may enhance floral initiation, and at the very least would not have any apparent detrimental side effects.
Education
A list of 2452 potential workshop participants was compiled from various sources including already established grower contact lists from our SARE Goldenberry Project LNE18-362 as well as extensive internet searches.
An e-mail inviting them to participate in our educational program scheduled for late 2021 and early 2022 was sent to all members of the list on 1/11/2021.
The following invitation was sent:
----------------------------------------------------------------------------------------------------------------
Strawberry Flower Mapping for Nitrogen and Row Cover Management Workshop
January 11, 2021
Hello,
We hope that you and your loved ones are safe and well.
We would like to invite you to participate in our newly funded Northeast Region SARE Project LNE20-395-34268, ‘Empowering Northeastern Strawberry Growers with Flower Mapping’.
If you are interested in participating, just respond YES to this e-mail, and we’ll be in touch.
This project will study flowering and fruiting in strawberry in relation to fall nitrogen and row cover management. We will be conducting flowering research at two Rutgers research farms and holding workshops or virtual demonstrations to teach growers how to flower map in conjunction with regional grower meetings. Flower mapping will help you with your nitrogen and row cover management decisions.
This project is open to all strawberry growers in the northeast region however workshops will be limited in size. Participants will be taught simple flower mapping and asked to implement the technique on their farms. Project participants will be provided a dissecting kit and dissecting scope which can be connected to a laptop or your phone (IOS or Android). The scope is capable of taking pictures, thus you can email photos to us for help in interpretation and production suggestions based on your flower maps. The dissecting equipment and scope will be provided at no cost to participants and can be kept when the project is complete.
Participation will require an hour or so per week from August through December (after your training session) for flower mapping and consultation. Participants will be expected to submit yield data and to evaluate effectiveness of the technique and provide feedback regarding the project.
By the end of the project, participants will be able to flower map strawberry plants on their farms and base management decisions on how their plants are growing rather than by relying on generalized, traditional and calendar based recommendations.
If you are interested in becoming a project participant please contact Ed Durner (durner@sebs.rutgers.edu) and you will be e-mailed an application and brief questionnaire (10 minutes to complete). Each workshop is limited to 25 participants so the sooner you get your application in, the better. If you have any questions, please feel free to contact us (e-mail is best). Also, feel free to pass this invitation along to anyone you might think is interested.
Thanks for your consideration,
Ed & Pete
Edward Durner Peter Nitzsche
Associate Research Professor County Agent I / Professor
Department of Plant Biology Department of Agriculture and Natural Resources
School of Environmental and Biological Sciences Cooperative Extension of Morris County
Rutgers, The State University of New Jersey P.O. Box 900
59 Dudley Rd., New Brunswick, NJ 08901-8520 Morristown, NJ 07963-0900
durner@sebs.rutgers.edu nitzsche@njaes.rutgers.edu
This material is based upon work supported by the National
Institute of Food and Agriculture, U.S. Department of Agriculture,
through the Northeast Sustainable Agriculture Research and
Education program under sub award number LNE20-395-34268.
------------------------------------------------------------------------------------------------------------------
Our education plan for this project consisted of: (1) holding virtual online workshops as well as virtual presentations at regional fruit meetings to teach strawberry growers simple flower mapping techniques, (2) providing growers the equipment to perform on-farm flower mapping and (3) providing post-workshop assistance and management recommendations when requested by participants.
In-person workshops were not feasible due to COVID restrictions.
We provided growers with providing growers the equipment to perform on-farm flower mapping as well as access to online video instuction for flower mapping technique. We aslo provided assistance whenever requested to help growers learn how to flower map. We had hoped that by providing instruction, equipment and post-workshop support, we would build grower confidence and encourage adoption of this simple management tool to enhance strawberry production in the northeast. Unfortunately this did not occur, most likely due to the lack of diret one-on-one, in-person instruction which I think would have greatly enhanced the learning process.
Milestones
Fruit and vegetable growers in the Northeast receiving an e-mail describing this project are invited to participate in a flower mapping workshop to be held at grower meetings as described above.
2452
2453
June 01, 2020
Completed
March 01, 2021
An e-mail inviting growers to participate in this project was sent to 2452 growers on 1/11/2021. The delay was due to increased efforts to create a larger potential participant list.
This milestone was completed 1 March 2021.
Virtual presentations explaining this project and flower mapping were made to growers at the 2021 New Jersey Agricultural Convention and Trade Show, (February 24, 2021), the Mid-Atlantic Strawberry Programs (MASP). Webinar (March 2021) and the Southeastern Plasticulture Strawberry School, Part Three: Fruiting – Flower Mapping. Webinar (April 20, 2021).
50
100
February 01, 2021
Completed
April 20, 2021
Three webinars were presented to encourage growers to participate in this study to learn flower mapping. Twenty eight growers expressed interest in participating.
The first flower mapping workshop is held virtually in 2021 (due to COVID) and growers learn simple flower mapping.
25
20
December 31, 2021
Completed
December 31, 2021
Due to the limitations for in-person interactions imposed by COVID, digital microscopes were shipped to 20 growers in 2021. Thirty-one growers requested registration forms, however only 20 returned them to provide a shipping address. The multiple e-mails sent to the growers who did not respond to encourage participation were ineffective.
Three videos were provided online for growers to view to introduce themselves to flower mapping:
Video One - Strawberry Flowering Physiology (~ 15 minutes)
https://drive.google.com/file/d/1eQqmSeR-3pDBIC4hLP9h7PXgQZHqkPxY/view?usp=sharing
Video Two - Setting up and installing your Plugable Digital Microscope
https://drive.google.com/file/d/1u1DXH6m9fx_9fhFbTbodMgN2w-y5GMt1/view?usp=sharing
Video Three - Flower Mapping A Strawberry Plug Plant (~ 15 minutes)
https://drive.google.com/file/d/1QbjJl9wXm0tA5OI8ebPBitXHpTwhJMiT/view?usp=sharing
The first video provides a discussion of strawberry flowering physiology, the second video demonstrates microscope use and software installation and the third video demonstrates flower mapping.
Growers were encouraged to view the videos and practice flower mapping on their own until such time as they are able to attend one of the in person sessions scheduled for spring of 2022 at the Mid-Atlantic Fruit and Vegetable Convention in Hershey, PA and the NJ Agricultural Convention and Trade Show in Atlantic City, NJ.
The second flower mapping workshop is held at The Mid Atlantic Fruit and Vegetable Growers Association Annual Meeting in Hershey, PA January 2022 and growers learn simple flower mapping.
25
48
January 31, 2022
Completed
February 03, 2022
The second flower mapping workshop is held at The Mid Atlantic Fruit and Vegetable Growers Association Annual Meeting in Hershey, PA February 2022 and growers learned simple flower mapping from a video presentation.
The third flower mapping workshop is held at The New Jersey Agricultural Convention, Atlantic City, NJ, February 2022 and growers learn simple flower mapping.
25
35
February 28, 2022
Completed
February 09, 2022
The third flower mapping workshop is held at The New Jersey Agricultural Convention, Atlantic City, NJ, February 2022 and growers were provided an introduction to simple flower mapping.
Growers try flower mapping on their farms, submit maps to us via e-mail and we help them interpret their maps and evaluate management choices for their specific situation.
35
2
December 30, 2022
Completed
December 31, 2021
While nearly 40 dissecting kits were distributed to growers for flower mapping, only 2 have reported that they have tried and used flower mapping on their farms. A number of growers expressed frustration with the tedious nature of flower mapping.
Flower Mapping workshops are held at Hershey and Atlantic City a second time for growers who did not participate the first year and growers learn simple flower mapping.
50
February 28, 2023
Incomplete
Grower interest in another workshop was lacking, thus this workshop was cancelled.
Additional growers try flower mapping on their farms, submit maps to us via e-mail and we help them interpret their maps and evaluate management choices for their specific situation.
35
November 15, 2023
Incomplete
Grower interest was non-existent. No growers continued with flower mapping, thus photos or maps were not avaialble to submit for review.
A flower mapping workshop is held at the New England Vegetable and Fruit Conference in 2023 for growers who did not participate in 2021.
25
November 15, 2023
Incomplete
This workshop was not held due to COVID restrictions and scheduling conflicts. Growers were given the opportunity to participate via online instruction.
All growers try/continue flower mapping on their farms, submit maps to us via e-mail and we help them interpret their maps and evaluate management choices for their specific situation.
150
November 15, 2023
Incomplete
Grower interest was non-existent. No growers continued with flower mapping, thus photos or maps were not avaialble to submit for review.
All growers who participated in the workshops and this project are surveyed regarding the project, the quality of the workshops, the usefulness of flower mapping on their farm, and whether or not they routinely use flower mapping as a management tool.
150
November 15, 2023
Completed
November 30, 2023
No responses to the survey were received.
Milestone Activities and Participation Summary
Educational activities:
Participation Summary:
Learning Outcomes
The change in knowlege from this project was an increase in understanding floral initiation and the concept of flower mapping. While growers did not adopt the practice, introduction of the concept has increased grower awareness of the importance and implications of fall nitrogen application on strawberry production.
Performance Target Outcomes
Target #1
75
Growers will adopt flower mapping to generate on-farm, science-based knowledge to make production management choices.
75 farms
Increase in production of at least 1,000 lbs fruit on at least 1 acre per farm.
Farmers lost interest in this project.
Unknown
Growers learned the complex nature of strawberry flowering and how nitrogen fertilization can impact the process.
Unfortuneately, growers lost interest in this project. The response to our initial invitation to participate was relatively low ( ~31 growers out of 2500 e-mail invitations sent). Part of the problem was this project and associated workshops had to be modified from in-person workshops to virtual workshops due to the pandemic. Another part of the problem is that flower mapping is tedious and takes patience and time. Not every one that might be interested in using flower mapping has the time to practice the process.
I think that a flower mapping service would serve the strawberry industry well, much like a soil lab provides nutrient, pH, nematode, etc. information to growers.
Additional Project Outcomes
Strawberry growers did not adopt the practice of flower mapping. However, strawberry growers gained significant knowledge regarding the complexity of the flowering process in strawberries. Many growers commented after various presentations that they finally understood how "flowering in strawberrries works". Growers were introduced to the concept of flower mapping and learned why it is a useful tool. They also learned how important the timing of fall fertilization of plasticulture strawberries can influence flowering and subsequent yield.
A major Specialty Crops Research Grant in the amount of $5,294,195 was awarded to a group of 19 strawberry researchers across the United States to address the issues associated with the strawberry nursery industry. According to the reviewers of the grant, a significant positive aspect of the proposal was the work regarding flower mapping and floral manipulation with conditioning. Both investigators in this SARE grant are part of that team, with Nitzsche leading the Extension and Outreach component and Durner leading the flower mapping and floral manipulation studies. Our involvement in the SCRI grant is a direct result of this SARE grant. We were the first team in North America to use flower mapping extensively in our research on strawberries and a direct consequence of that work was a significant increase in the number of researchers using the technique.