Progress 06/15/20 to 06/14/24
Outputs
Target Audience:In Maine and Nova Scotia our target audience is made up of small, medium, and large wild blueberry growers and processors that produce berries both conventionally and organically. The native lowbush (wild) blueberry (Vaccinium angustifolium) is an economically and culturally important crop that had a farm gate value of $80.3 million in 2021, up from $28.5 million in 2020. As more berries are planted around the world, the value of frozen wild blueberries in Maine has dropped yet due to pandemic health centric consumers and value added efforts as a result of this project and others, has increased. Grown commercially by 485 farmers on 42,000 acres in Maine and 46,000 acres in Nova Scotia, 76% of Maine growers surveyed did not make a profit in 2017 (Yarborough 2018) and this project aimedto expand the number of farms that offer a vaue-added wild blueberry item to the market. Jim Meyers left his position at Cornell and therefore we did not continue the wine grape aspect of this project in the final year. Changes/Problems:
Nothing Reported
What opportunities for training and professional development has the project provided?3undergraduate students were hired during the final year of this project 1 full time technician worked on this project in the final year How have the results been disseminated to communities of interest?Yes, in the final year of this project we highlighted value-added options 34% (14/41 respondents) indicated that they learned something new about fresh packing wild blueberries and 9% indicated that they would implement something learned related to fresh pack, 29% (12/41 respondents) indicated that they learned something new about freeze drying wild blueberries, and 56% (23/41 respondents) indicated that they learned something new about wild blueberry wine production, What do you plan to do during the next reporting period to accomplish the goals?
Nothing Reported
Impacts
What was accomplished under these goals?
Phenological Development Fruit per stem for ME and NS in 2023 were similar in each fruit growth stage (Figure 1). The number of color change fruit was so low in ME and NS because the fruit change from green to blue almost overnight, and data is not collected every day, thus it appears to be low in the data (Figure 1). The number of green fruit per stem is greater than blue fruit per stem. Some of this loss can be correlated to what farmers call the "June Drop" (Drummond, 2002). This is when the plant drops fruits early because it cannot support the fruit load due to under fertilization, or the plant is sterile leading to fruit abortion (Drummond, 2002). Other sources of loss may be from disturbances such as sampling or over-ripe fruits. This season there was very little overripe fruit given the cooler wet conditions of the harvest. Plant Nutrient Content Nitrogen content of crop leaves is known to improve plant photosynthesis and therefore yield. Recently, it has been found to increase blueberry fruit polyphenols and soluble protein (Zhang et al., 2023). Applying a 21% N ammonium sulfate or a 37% N sulfur coated urea was found to increase fruit per stem and stem growth with a spring application on wild blueberry (Precival and Privé, 2000). Results found in our study contradict the notion that N increases yield. We did not find yield to be significantly affected by N (Tables 4 and 5). Our crop year fruit and leaf samples showed that nitrogen content started at an optimal level and dropped below optimum levels at green fruit (Figure 2). This is the same seasonal trend observed in multiple varieties of highbush blueberry (Strick and Vance, 2015). In wild blueberry, N started out at 2.0%N and dropped to 1.5% while in highbush N started at 3.5% and dropped to 1.5-2.0% (Strick and Vance 2015). Highbush blueberry growers apply a split application of ammonium sulfate at pre-bloom (T5) and at green fruit. Our wild blueberries are using N during the crop year. In the 1990s it was observed that wild blueberry fields were lacking in phosphorous and therefore growers were encouraged to apply DAP and MAP. At the time, an increase in phosphorus led to an increase in wild blueberry yield (Smagula and Dunham, 1995). However, 2022 and 2023 data from ME and NS locations suggest that phosphorus does not directly increase yield but is needed to make a more robust model for predicting yield (Table 4 and 5). In addition, we observed a decline of phosphorus within the fruit and leaves which suggests the plant is using this nutrient over the season. This is the same seasonal trend observed in multiple varieties of highbush blueberry (Strick and Vance, 2015). In wild blueberry P started out at 0.25-0.30%P and dropped to 0.10% while in highbush, P started at 0.40% and dropped to 1.5-2.0% (Strick and Vance 2015). Wild blueberry starts and ends a little lower in P compared to highbush. Potassium in the leaves started at 0.6% slightly above optimum and dropped to 0.4% by harvest (Figure 4). According to Strick and Vance (2015), highbush blueberry varieties started out with 0.80-1.1%K and dropped to 0.50%. Making sure sandy soils have adequate potassium for plant uptake is important and needs to be balanced with correct application rates or it can leach out of the soil. Percival and Sanderson (2004) found the soil application of potassium to directly increase stem density and fruit set. Having adequate potassium levels was found to increase soluble sugar and decrease titratable acidity in highbush blueberry (Zhang et al., 2023). Zhang et al. (2023) results follow the same trend we found with an increase of potassium in leaves leading to an increase in fruit brix (Figure 9; Table 7). Research on calcium applications to wild and highbush blueberry have varied and do not uniformly show that increased rates of calcium improve fruit quality (firmness or reduce fruit drop). Studies do not show an increase in yield from calcium applications. Instead, the range of results indicates that local climatic conditions, specific highbush cultivar, and timing of calcium applications may be the greater influences on fruit quality (Yang et al., 2019; see "Foliar Calcium Study" on page B91 in the 2022 report). In this study we found that increased calcium content in the leaves correlated to an increase in yield (Figure 8). However, the relationship is stronger in the multivariate linear regression when potassium and magnesium are paired with calcium in the model for predicting yield. Several years in a row we have seen that calcium increases through the season in the same manner that highbush blueberry varieties do. In this study, wild blueberry leaves started out at 0.3% and increased to 0.6% while according to Strick and Vance (2015), highbush varieties started out at 0.3-0.4% and increased to 0.8%. Brix was negatively correlated with yield (Figure 6; Table 4). This suggests that as fruit ripens (brix increases), fruit falls off, reducing the yield that we measure. Cooler temperatures and increased precipitation in 2023 allowed farmers to harvest for a longer period of time reducing the amount of over-ripe fruit. The model for predicting brix found that fruit sugar content depends on macro- and micro-nutrients, not just on nitrogen, phosphorus, and potassium. Imaging for Ripeness and Quality In the first year of the study, after testing four different models the 2-class, YOLOv4-Tiny performed the best out of the four which is encouraging as YOLOv4-Tiny is computationally much cheaper than YOLOv4 (MacEachern et al., 2021) and as these models are transitioned into real time implementation, YOLOv4-Tiny is likely to be the choice of network for this reason (Figure 10; Table 9). The success of the 2-class models, while providing somewhat less information, do a better job at accounting for all pictured berries (Tables 8 and 9). All four of the models do a good job of predicting yield with root mean square errors less than 28.87 g. Considering the results of the models from all second year (2022) images, a significant reduction in model performance can be seen. This is likely the result of inconsistent image quality observed in the Maine images. Key contributors are likely to be the inconsistent angle and height of images along with the relatively lower image quality. Maine images were collected at various resolutions whereas all Nova Scotia images were collected at 5184 x 3456 pixels. In all cases, the resolution of Maine images was lower than Nova Scotian images. While it is not imperative to have identical resolutions for publication, it would smooth out the process especially where we are not trying to prove the methodology. It is advisable that Maine images be collected at the same resolution moving forward. After plotting the actual versus predicted values for each of the datasets the Nova Scotia 2023 data can be confirmed as the best model by the RMSE (Figure 14). Despite this, it is still possible that the combined datasets better account for the variation across a variety of image qualities and spatiotemporal parameters (Figure 13; Table 13). The recommendation of the researchers would be to employ the Nova Scotia 2023 model if one can assure that the captured image quality and parameters follow the methodology exactly (Figure 14). Otherwise, it is advisable that the combined 2023 model be used to account for image variability (Figure 13). Considering the results of the models from all third year (2023) images, yield can be well predicted using quality images taken at a standard height and position. Nova Scotia's model for predicting yield was less accurate with the images taken in Maine due to collection technique (Figure 13). However, the model can be quite useful for wild blueberry growers and researchers.?
Publications
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Progress 06/15/22 to 06/14/23
Outputs
Target Audience:In Maine and Nova Scotia our target audience is made up of small, medium, and large wild blueberry growers and processors that produce berries both conventionally and organically. The native lowbush (wild) blueberry (Vaccinium angustifolium) is an economically and culturally important crop that had afarm gate value of$80.3 million in 2021, up from $28.5 million in 2020. As more berries are planted around the world, the value of frozen wild blueberries in Maine has dropped yet due topandemic health cetnric consumers and value added efforts as a result of this project and others, has increased. Grown commercially by 485farmers on 42,000 acres in Maine and 46,000 acres in Nova Scotia, 76% of Maine growers surveyed did not make a profit in 2017 (Yarborough 2018) and this project aims to improve the number of growers who make a profit. Jim Meyers left his position at Cornell and therefore we did not continue the wine grape aspect of this project in the final year. Changes/Problems:Dr. Jim Meyers has left Cornell University Extension and therefore grapes and he are a lesser part of this project. He has agreed to analyze the 2023 wild blueberry architecture data which will be very helpful. No grape data is being collected in 2023. What opportunities for training and professional development has the project provided?The data collected through this project lead to an undergraduate honors thesis project in 2023. Data on leaf and berry nutrients collected from 2020, 2021, and 2022 shows a clear drop in nutrients in the crop year. An undergraduate is working with Dr. Calderwood to study crop year applied granular ammonium sulfate and it's impact on berry quality and yield. Two additional students, one from UMaine and one from Northern Michigan State are working on this project and others during the 2023 season. Inpart due to the skills learned during this project the technician working on this in 2021 and 2022 took a new position with Wyman's of Maine which builds their workforce. Wyman's receently diversified their products to include juice and ice cream type desserts.A new technician was hired and is now learning wild blueberry quality measures. How have the results been disseminated to communities of interest?2022 New England Fruit and Vegetable Growers Conference in Manchester NH included a talk by Dr. Calderwood introducing wild blueberries with some data from this project and basic berry quality information. 50 attendees 2023 Wild Blueberry Conference in Bangor ME included guest speaker Peter Van Dyk from Nova Scotia who shared what he has learned about making wild blueberry juice on a large scale. The Nova Scotia Producers Association also presented findings from a fresh pack packaging study they conducted. Dr. Travis Esau presented modifications to wild blueberry harvesters that improve berry quality. 90 attendees 2022 Research and Extension Report was written, edited and distributed to 300 people in the winter of 2023. This included a farmer friendly research report on the findings of this research to date. What do you plan to do during the next reporting period to accomplish the goals?Produce a final berry quality recorded webinar. Nutrient fluxuations through the season and regressions showing relationships between nutrients and berry pH, Brix, and yield will be highlighted. Producefactsheets and update webpages on fertility management in relation to berry quality. Quantify number of pounds sold through the berry connection and other connections made from this project. Prublish paper based on IFT presentation made in July 2023.
Impacts
What was accomplished under these goals?
Objectives 1 and 2: Field Nutrients as related to Food Science Measures Overall, leaf macro nutrient levels (N, P, K) decreased over the growing season, while certain micro (Ca, Mg, Fe, Mn) nutrients levels increased over time, yet Zn decreased over time. All locations appeared to trend similarly in leaf nutrient levels over the flower, green, color change and blue fruit stages. NS samples experienced a quicker decrease in K levels after the flower stage compared to Maine samples. Blueberry fruit macro (N, P, K) and micro (Ca, Mg, Fe, Mn, Zn) nutrients decreased from flower as fruit matured from green to blue. This downward trend was similar at all ME and NS locations. Relationships Between Yield, Quality and Leaf/Fruit Nutrient Levels: Multivariate linear regressions performed on yield and Brix resulted in an R2 of 0.68, which suggests that 68% variation in yield may be explained by Brix. This is likely due to the fact that as blueberries ripen, weight decreases, while Brix continues to increase. Fruit Yield and Nutrients: Based on bivariate linear regressions, fruit Brix (p<0.002), leaf Ca (p<0.002), and leaf K (p<0.007) levels showed a significant linear relationship with yield. Fruit Brix and Nutrients: Brix and leaf potassium levels appeared to have an inverse relationship with yield. Whereas, leaf calcium levelshad a positive relationship. Fruit N (p=0.0009), K (p=0.004), Fe (iron, p=0.02), as well as leaf K(p<0.0001) and Fe (p=0.0005) levels showed significant positive relationships with Brix levels. The Columbia Falls location in Maine had a higher iron concentration compared to the other sample locations, which may have skewed the data. Fruit pH and Nutrients: Berry pH levels showed a significant positive linear relationship to fruit N (p=0.005) (Figure 3) and K (p<0.0001) values, but no other relationships were found between berry pH values and the other fruit nutrients analyzed. However, leaf micronutrients K (p<0.0001), Ca (p=0.044), Mg (p=0.013), and manganese (Mn, p=0.002) all appeared to have significant positive linear relationships with berry pH. Conclusions Blueberry leaf (except Ca) and fruit nutrient levels decreased over the growing season (regardless of fertilizer management practices), which suggests that the plants are utilizing these nutrients towards growing and maturing fruit. Higher fruit yields corresponded with lower fruit Brix and leaf potassium values, but higher fruit yields were associated with higher leaf calcium levels. As fruit becomes over ripe, berries shrink in size (reducing yield) while Brix levels continue to rise. Higher fruit Brix values corresponded with higher fruit nitrogen and potassium levels and also higher leaf potassium values, but higher Brix values were associated with lower iron in fruit and leaves. Higher fruit pH levels corresponded with higher fruit N and K levels, along with higher leaf K, Ca, Mg and Mn levels. As fruit pH increased, it appears that nutrients became available to the plant for uptake into the fruit. Overall, leaf nutrients in the crop year of wild blueberry production declined. This indicates a need to study fertilizer applications in the crop year, a practice that would be new to this production system. The positive relationships of N and K with Brix warrants further study for markets that seek sweeter berries while the positive relationship between Ca and yield was surprising. Studies do not consistently show a benefit to foliar Ca applications on fruit quality (Yang et al. 2019) yet the impact of ground applied Ca on yield would be worth studying in wild blueberry. Future work will need to address the optimum mode and timing of application for N, K, and Ca. Objective 3: Extension A total of 459 people attended Dr. Calderwood's events in Maine, 200 of which attended a value-added or berry quality event. 170 people attended a Canadian wildblueberry field event at Van Dyk's juice processing facility in Nova Scotia in July 2023. Dr. Calderwood attended Fresh Pack and Value-Added Committee of the Wild Blueberry Industry meetings in February 2022 and 2023. Discussed value-added powder, chips, and tea and presented research data from fresh pack cooling study and berry quality development data from this project. Dr. Calderwood held a value-added field meeting at Fields Fields Farm that makes wild blueberry tea, crisp, and chips where there were 15 attendees in May 2023.
Publications
- Type:
Conference Papers and Presentations
Status:
Published
Year Published:
2023
Citation:
Calder, B, T. Esau, B. Tooley, M. Scallon, and L. Calderwood. July 2023. Institute for Food Technologists Conference. Assessing lowbush blueberry (Vaccinium angustifolium) quality and nutrient changes throughout the growing season. Presentation.
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Progress 06/15/21 to 06/14/22
Outputs
Target Audience:In Maine and Nova Scotia our target audience is made up of small, medium, and large wild blueberry growers and processors that produce berries both conventionally and organically. The native lowbush (wild) blueberry (Vaccinium angustifolium) is an economically and culturally important crop that had afarm gate value of$80.3 million in 2021, up from $28.5 million in 2020. As more berries are planted around the world, the value of frozen wild blueberries in Maine has dropped yet due topandemic health cetnric consumers and value added efforts as a result of this project and others, has increased. Grown commercially by 485farmers on 42,000 acres in Maine and 46,000 acres in Nova Scotia, 76% of Maine growers surveyed did not make a profit in 2017 (Yarborough 2018) and this project aims to improve the number of growers who make a profit. Red grapes (Vitis vinifera) are an economically valuable crop in New York State, contributing $4.8 billion to the state's economy where they enter stores as wine, juice, and table grapes (NY Wine and Grape Foundation 2019). However, the Finger Lakes region of the state has excelled due in part to regionally specific ripening knowledge. Therefore the target audience in NY are the Eastern NY grape growers looking to improve grape quality. Changes/Problems:
Nothing Reported
What opportunities for training and professional development has the project provided?Thus far, seven people have been trained in measuring berry quality and plant architecture. Five of these are undergraduates who have certainly gained professional development from working on aspects of this project. Two full time technicians (one funded on this grant) have gained professional development through program and field data collection management. They have also learned from collaborating PIS about their work and perspectives. How have the results been disseminated to communities of interest?Two discussion group sessions with wild blueberry grower panels were offered online as part of the UMaine Wild Blueberry Conference. One was "Improvements to Fresh Pack Lines for Quality and Food Safety" which had a lively discussion about how to meet rising demand for fresh berries and how to improve food safety on these lines (40 attendees, virtual). The second was titled "Expanding into Value-Added Products" which featured small scale value-added business who shared their successes and challenges (30 attendees, virtual). On the UMaine Wild Blueberry website (https://extension.umaine.edu/blueberries/) "Marketplace" tab has been re-arranged to provide a connection to suppliers and buyers, equipment (new and used), and a listing of fresh pack and value added producers. Calderwood attended a Fresh Pack and Value Added Committee meeting int eh winter of 2021/2022 where this project was shared and feedback given. On July 7, 2022 Calderwood held a Fresh Pack Wild Blueberry field meeting at Welch Farm where growers met to discuss improvements to fresh pack berry quality. On July 14, 2022 berry quality was discussed at the UMaine Blueberry Hill Farm field day in Jonesboro, ME. Research results were documented in a report contained within the Annual UMaine Wild Blueberry Research Reports 2021 which was distributed to 700 contacts via the UMaine Extension Newsletter and mailed in print to 100 contacts through a sign up process. What do you plan to do during the next reporting period to accomplish the goals?For the second year of this project we plan to modify some of our data collection methods to improve consistency between PIs, continue data analysis, communicate with the DalHousie food scientists to brain storm ideas, and offer a wine centric berry quality event along with planned data collection and events.
Impacts
What was accomplished under these goals?
? Objectives 1 and 2. Phenological Development As expected due to latitude differences, ME accumulated GDD faster than NS with 660 more GDD than NS by peak blue fruit (ME: July 28, NS: Aug 3). ME crop stages were ahead of NS until green fruit which occurred the week of June 22 in both locations, indicating that temperature alone cannot predict berry development in wild blueberry (Spinardi et al., 2019). NS exhibited many more buds, flowers and green fruit per stem than ME but upon reaching the blue fruit stage, both territories had very similar numbers of blue fruit per stem. Plant Nutrients Percent N, P, and K in leaves indicated that leaves during full bloom had a high nutrient content across locations which dropped down to the UMaine Analytical Lab and Soil Testing Service's standard ranges for each nutrient in leaves at the green, color change, and blue fruit stages. This shows the "source-sink" relationship we expected to see where nutrients from leaves were shifted to fruit or other parts of the plant once fruit began to form (Doyle et al., 2021). Interestingly, however, the fruit nutrient content data didnot support the "source-sink" concept: over the course of fruit development, N, P, K, and Ca levels decreased. The standard leaf recommendations do not translate to flower or fruit recommendations, but it is interesting to note that N and Ca dropped well below the leaf standard recommendations. Further investigation and literature review is required. Plant Architecture and Berry Quality A correlation between pH, Brix, and TA was only observed with color change fruit. A possible explanation for the difference in responses across the three fruit ripening stages is that green fruit is still largely undifferentiated early in the season, meaning that green fruit is hidden behind leaves. The lack of correlations in blue fruit could suggest that the effect of sunlight exposure on Brix is short lived and only impacts fruit during color change, but future data is needed to draw any conclusions. Quality The %Brix/%TA ratio (Bx/TA; or sugar-to-acid ratio) was calculated to measure overall sweetness and tartness changes among samples, which is illustrated in Figure 6. The Bx/TA ratio increased during fruit development from red to blue fruit and ranged from 24.25 to 35.48. The highbush blueberry industry uses a suggested fruit quality standard of 10.0 to 33.0 Bx/TA ratio as an acceptable range for blueberries (Beaudry, 1992). Wine Spoilage Lactic acid bacteria are overwhelmingly considered detrimental to wine quality because they acidify the product. Depending on which genera are present, these bacteria also produce various defects including buttery odor and flavor and ropiness (a texture that can be slimy or viscous). The impact of yeast on wine quality is more complex. Yeast can significantly impact the volatile organic compound (VOC) composition of the finished wine. Generally, any yeast found would be expected to ferment juice and yield something that could be considered a wine. However, yeasts also have the capability to 1) produce different alcohols (as opposed to ethyl alcohol produced by brewing yeasts) and esters (usually beneficial, contributing fruity/floral aromas); 2) differentially reduce aldehydes or not; 3) most notably produce volatile phenols, which cause defects such as a "band-aid smell." The levels of yeast represented here would be sufficient to drive a spontaneous fermentation. Further investigation is required to determine what species are present and how stable the community is because these yeasts could either produce a very variable product if unstable or if stable, could potentially lead to the reproducibleproduction of unpleasant characteristics (in smell, texture, or taste). Objective 3. Two discussion group sessions with wild blueberry grower panels were offered online as part of the UMaine Wild Blueberry Conference. One was "Improvements to Fresh Pack Lines for Quality and Food Safety" which had a lively discussion about how to meet rising demand for fresh berries and how to improve food safety on these lines (40 attendees, virtual). The second was titled "Expanding into Value-Added Products" which featured small scale value-added business who shared their successes and challenges (30 attendees, virtual). On the UMaine Wild Blueberry website (https://extension.umaine.edu/blueberries/) "Marketplace" tab has been re-arranged to provide a connection to suppliers and buyers, equipment (new and used), and a listing of fresh pack and value added producers. Calderwood attended a Fresh Pack and Value Added Committee meeting int eh winter of 2021/2022 where this project was shared and feedback given. On July 7, 2022 Calderwood held a Fresh Pack Wild Blueberry field meeting at Welch Farm where growers met to discuss improvements to fresh pack berry quality. On July 14, 2022 berry quality was discussed at the UMaine Blueberry Hill Farm field day in Jonesboro, ME.
Publications
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Progress 06/15/20 to 06/14/21
Outputs
Target Audience:The first year of this project was 2020 during Covid-19. Unfortunately the three collaborating Universities on this project were not able to function at full capacity and therefore we have begun both research and outreach portions of this project online and largely in 2021. Over the course of the first year our direct target audience were wild blueberry and grape producers online. The project was introduced to many groups who now anticipate the project. We reached wildblueberry growers and processors in Maine, New York, and Nova Scotia using existing grower lists and online meetings. In Maine, the UMaine Wild Blueberry Conference was held virtually from January-March. Value-added talks were presented to and by growers and stakeholders. In Maine, the native lowbush (wild) blueberry (Vaccinium angustifolium) is an economically and culturally important crop that, in 2008, brought in $54.8 million to the state. Changes/Problems:As mentioned, 2021 has really been the start of this project due to the lack of labs to process samples during Covid-19. We are on track now. What opportunities for training and professional development has the project provided?The technicial staff supported by this project has joined our team and has been trained in the appropriate analyses. Technician: trained in titratable acidity, brix, color, and lab protocols. Undergraduates: 1 trained intitratable acidity, brix, color, and lab protocols in additon to 1 trained in microbiology cultures PI Team: collaborating well, and in touch about field data collection methods regularly. Wild blueberry PIs have learned about canopy measurements and grape PI continues to learn about the unque wild blueberry crop. How have the results been disseminated to communities of interest?2021 is the first year of data collection. Results have not been reported yet. What do you plan to do during the next reporting period to accomplish the goals?1. Competeyear 1 data collection by September 1, 2021 2. Enter all data by November 1, 2021 3. Write up grower research report by December 15, 2021 4. Disseminate year 1 results at UMaine Wild Blueberry Conference (February 2022), Downeast Rural Development Working Group Meeting, Wild Blueberry Commission of Maine Committees, and Ag Trade Show. 5.Calderwood's team will meet with Extension Publication Professionals to design The Berry Connection and contacteXtension as a new contributor to online content during winter 2021/2022.
Impacts
What was accomplished under these goals?
Objective 1. We have set up all on-farm research plots, ordered all equipment and supplies to collect the data required. We have met as a group to discuss data collection methods and entry. We have hired the technician, grad student, and undergraduates required to collect 2021 data. Objective 2. The labs required for analysis are back working at full capacity. Personnel have been trained to run samples and samples are now being collected for the first green fruit measurements. Objective 3. Conversations with the Wild Blueberry Commisstion of Maine have begun around value-added products and the need to build platforms for farmers and stakeholders to interact.
Publications
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