Progress 11/15/23 to 11/14/24
Outputs
Target Audience:Target audiences for our project include academic researchers, germplasm developers, growers of silage corn, stakeholders in the silage industry, and the general public concerned with crop health and heat wave impacts more broadly. This year, we reached many of these audiences by presenting at conferences in Florida and the silage corn field day in Citra, FL. A manuscript is in preparation for submission to a peer reviewed journal relaying the findings from our heatwaves across ontogeny study in silage corn, including our assessments from in-field variety trials and thermotolerance measurements across ontogeny; a first-ever study in this crop. Changes/Problems:
Nothing Reported
What opportunities for training and professional development has the project provided?This project provided the opportunity for professional development for a student who was finishing her undergraduate degree, Emily Perry. The research experience gained working for a year on this project following her undergraduate studies provided Emily will the skills, experience, and confidence to be admitted to UF's competitive graduate college. She has now begun a Ph.D. in plant ecophysiology in the lab of PD Hammond, and the development she received during this project--during which she executed and presented her first first-author scientific presentations (orally, and two poster presentations), were key to her growth and current success. The project also provided professional development opportunities to PD Hammond, Co-PDs Wallau and Fraise, as they interacted for the first time in an interdisciplinary way--sharing perspectives from ecophysiology, forage extension, and crop modelling respectively. A synergistic approach to research and extension was developed among the PD and Co-PDs that is expected to continue beyond this project--they remain in contact and are actively developing future efforts to work together on future interdisciplinary projects. How have the results been disseminated to communities of interest?Our project included hosting the 2024 Silage Corn field day in Citra, FL. This event was well attended, with over 130 atteendees in person representing corn growers, seed companies, and land managers. There was high interest in oral presentations by Dr. Wallau, Dr. Sapes (a research scientist on the project) and student Emily Perry. Following the field day, Dr. Wallau conducted interviews to further understand the concerns and needs of stakeholders across Florida regarding heat stress on silage and other crops. Finally, Dr. Fraisse has worked on integrating the findings of this research into heat stress reports that can be generated via Agroclimate.org, an online decision management tool for growers. The model developed in Silage corn as a part of this project has great potential to be further expanded to additional crops via Agroclimate. Extension materials and outcomes The work developed through the variety trials is assisting farmers in Florida and Georgia to improve silage productivity and reduce the cost of production per ton of milk produced. Considering there are less 50 dairies in Florida, covering about 25,000 acres of corn silage, and attendants of the Corn Silage Field Day corresponded to about 60% of that area (based on land acreage reported on surveys), is fair to say we are reaching about half of that population of dairy farmers with our programs, events and content. Dairy farmers using our variety recommendation can have an increase of 30% in milk production per acre of crop planted with the same inputs, compared to randomly choosing a corn or sorghum hybrid. Considering an average of corn silage production of 28,500 lb estimated milk per acre, following the recommendations we provide results in an extra $1,800 per acre (considering $0.2078 per lb of milk), or about $26.6 M in 15,000 acres. As farmers become more aware and experience climatic challenges, the variety testing program becomes even more important as a resource for unbiased information on forage performance. Extension presentations: -Extension events (producer and industry audience) Suwanee & Columbia Counties Crop Updates Meeting - Feb 4, 2025 - attendance 14 participants Talk: Forage Crop Updates - Marcelo Wallau - overview of main results from variety trials, to help farms deciding hybrids to be planted and planting strategies. Corn Silage and Forage Field Day - May 30, 2024 - Attendance 134 participants Talk: Hybrid decision tool and 15 years of data - Marcelo Wallau, Diwakar Vyas, and Nicolas Caram - talk about the long-term analysis of corn and sorghum variety trial data, including a discussion on yield stability and factors influencing productivity and tolerance to stress. Talk: Thermotolerance in corn - Gerard Sapes and Emily Perry - discussion of the preliminary results from the thermotolerance assessment in corn hybrids from the 2023 trial. Extension communications -Cow talks podcast (audience - general producers, industry and extension; listeners ~350) Silage hybrid selection, with guest speaker Bill Mahanna, hosted by Marcelo Wallau and co-hosting with Diwakar Vyas, about critical factors influencing corn selection for silage, emphasizing the importance of agronomy, late season plant health, and the role of data models.https://open.spotify.com/episode/2M22EnbKHzJ2Cc3pq1hzBj?si=7b1138e669ad4e56 -Newsletter Wallau, M., M. Mailhos, C. Mackowiak and D. Vyas. 2024. Cool-season forage variety recommendations. Panhandle Ag e-News, UF/IFAS Extension. Aug 2, 2024. https://nwdistrict.ifas.ufl.edu/phag/2024/08/02/2024-cool-season-forage-variety-recommendations/ Wallau, M., O. Maule, A. Kanobroski and D. Vyas. 2024. What to Look for When Selecting Hybrid Corn Varieties for Silage? . Panhandle Ag e-News, UF/IFAS Extension. Jan 31, 2025. https://nwdistrict.ifas.ufl.edu/phag/2025/01/31/what-to-look-for-when-selecting-hybrid-corn-varieties-for-silage/ -Silage decision tool Hybrid decision tool website (536 views in 2024) - a repository of data from the corn and sorghum hybrid trails to help farmers on decision-making about materials to plant https://devfel.github.io/forage-hybrid-table/ -Website Corn Silage Field Day website - contains all data from the variety trials and all presentations from the Corn Silage and Forage Field Days https://animal.ifas.ufl.edu/extension/courses/csfd/. What do you plan to do during the next reporting period to accomplish the goals?
Nothing Reported
Impacts
What was accomplished under these goals?
According to these goals, we have accomplished the following: 1) identify state-wide impacts of this record-hot Florida growing season punctuated by a July heatwave on agronomic production and quality using silage corn as a model system Co-PD Wallau has conducted surveys of silage corn growers, and growers of other crops from around the state. In addition to our focal/model system of silage corn, the project also was able to phenotype 30 additional crops for thermaltolerance, creating a database of Florida crop thermal limits that serves an important foundation for understanding potential risks and future impacts of increased temperatures for agricultural production in the state. These data are part of an in-preparation manuscript, and will be DOI'd and shared according to reporting requirements as the manuscript is completed. Farmer Surveys: Our goal was to identify evidence of the negative impact of a heatwave from August 2023 on crop production (especially corn), gauge the use of research data such as variety trial results and climatic models, and assess current and future climate-related concerns. The survey was conducted using a semi-structured questionnaire with four objective and ten open-ended questions. We employed a non-probabilistic, purposive sampling method, involving farmers and consultants from our Extension contact list. We conducted nine interviews, each lasting approximately 30 minutes. The group represents the two main dairy regions in Florida, Okeechobee and the Suwanee Valley, with an approximate combined area of 15,000 acres planted with corn (both silage and grain), representing about 25% of the crop acreage in the state. Through our survey, we could not conclusively identify the effects of the 2023 heatwave on corn production, possibly because many farmers have been planting sorghum as a second crop following corn. However, several participants voiced concerns about extreme weather, particularly excessive heat and variability in rainfall. Several respondents noted that the heatwave caused poor pollination and unfilled ears. High temperatures (>95F) hindered plant growth despite adequate soil moisture, necessitating additional irrigation. However, some mentioned that even with full irrigation, plants could not keep up with evapotranspiration, resulting in crop loss. Most farmers interviewed are using the hybrid trial results, either accessed via the website (Excel spreadsheets) or the online tool. Some still contact Extension directly for hybrid selection assistance. Other management and decision-making tools mentioned include soil moisture probes, and tissue sampling; most utilize short-term weather forecasts. None mentioned using physiology-based models for management decisions, however some have shown interest as a potential management tool. Those planting corn for silage based their planting date decisions on the harvesting crew's availability as they custom-harvest their silage. For south Florida, the common harvesting date was by the end of May, and for North Florida by the first week of July. After that, the harvesting crews move north and there is no service available. Climate-Related Concerns Mentioned: Heat stress impacting pollination and grain filling. Nutrient leaching due to rain during high nutrient demand periods. Increased temperatures resulting in flash droughts and high night temperatures. Challenges with second-season planting and limited land availability. Timing of seasonal temperatures affecting forage and grain quality. Issues with high temperatures causing plants to fail to transpire sufficiently. Increased temperatures and nutrient management difficulties. Some respondents did not identify new challenges, focusing instead on ongoing issues such as heat and rainfall variability. 2) to quantify the thermal tolerance of the most and least impacted crops to identify traits to inform of future risk, with the overarching goal of generating a synthesis report to integrate the knowledge gained through our extension and research activities to inform growers across the state of Florida, along with peer-reviewed research revealing the mechanisms of heatwave damages in agricultural crops. For our second aim, we have identified the most impacted crops (likely, silage corn--our focal species), and a range of other crops including sub-tropical and tropical species sampled at UF's tropical research and education center (TREC) in Homestead, FL. The mechanisms of damage were found to be highly linked not only to maximum air temperatures in our heatwave chambers, but dependent upon the water status of plants. We found consistently higher damages in plants exposed to even mild drought stress, highlighting the importance of water management during periods of maximum heat stress. Additionally, through a greenhouse experiment in silage corn where we imposed the August 2023 heatwave at different developmental stages for five contrasting entries, we identified key phenological stages that are most vulnerable to extreme heat in silage corn. These stages include the late-vegetative and early-reproductive (V15-R1) stages, and heat vulnerability varied by genotype. Data from this experiment is being used to parameterize the heat risk thresholds in the Agroclimate.org forecasting tool, providing an opportunity for farmers to make an informed decision about heat risk for planting.
Publications
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