Grant Information
| Knowledge Area | Subject of Investigation | Field of Science | Percent |
|---|---|---|---|
| 205 - Plant Management Systems | 4099 - Microorganisms, general/other | 1103 - Other microbiology (includes protozoology, phycology, etc.) | 40% |
| 205 - Plant Management Systems | 999 - Citrus, general/other | 1103 - Other microbiology (includes protozoology, phycology, etc.) | 40% |
| 102 - Soil, Plant, Water, Nutrient Relationships | 110 - Soil | 1070 - Ecology | 20% |
Huanglongbing (HLB) or citrus greening has caused significant tree decline and economic losses. One of the major impacts of this disease has been the decrease of root growth, which also impacts nutrient and water uptake. The improvement of the soil environment through changes in the soil microbial community may provide improvements to root growth and therefore help mitigate the losses from HLB-induced tree decline and may improve overall productivity of non-affected trees. In other crops, changes to populations of plant growth promoting rhizobacteria (PGPRs) and the overall soil microbial community composition can improve root growth, reduce fertilizer application rates, and increase plant nutrient uptake. The application of soil amendments, both biotic and abiotic, is one method for altering the soil microbial community in an effort to impact root health and nutrient update.The goal of this project is to determine the impacts of soil amendments on the soil microbial community of citrus, and to determine if these impacts correspond to changes in tree health and productivity. While previous studies have examined the application of soil amendments on the crop microbial communities, many of these studies have only been performed in laboratory or greenhouse conditions, and it is unknown how these amendments will affect the soil microbial communities in field-planted tree crops, especially citrus and HLB-affected citrus. There are also numerous other factors that may impact the soil microbial community of citrus, regardless of HLB, including rootstock, tree age, soil type, and propagation method. The interaction of these variables on the soil microbial community of citrus trees is also unknown. Examining these connections between soil amendments and the soil microbial community in combination with changes in propagation method, soil type, tree age, and rootstock, will provide a basis for future research strategies for manipulating the soil microbial community to improve tree health.
The goal of this project is to determine the impacts of soil amendments on the soil microbial community of citrus, and to determine if these impacts correspond to changes in tree health and productivity. Many commercially available products claim to increase or enhance the soil microbial community, but there is little empirical data available on any changes to the community or the microbial functional groups. In addition, there is little information on the influence of tree age, rootstock, soil type, or propagation method on these interactions.
Objective 1. Greenhouse trials will be performed at the Southwest Florida Research and Education Center (SWFREC) and Citrus Research and Education Center (CREC) to examine the efficacy of soil amendments on the soil microbial community in citrus seedlings and different citrus propagation methods under controlled conditions. Different soil amendments will be applied to the soil, and plant height, leaf area, and root architecture will be assessed by a plant physiologist. Rhizosphere samples will be collected at the end of each trial and the general bacterial and fungal abundance in each sample will be assessed through quantitative PCR. More detailed analysis of the microbial community of different propagation methods will be done using shotgun metagenomics. Seedling greenhouse trials have already begun.Objective 2. Field trials of effective soil amendments will be carried out both at the SWFREC and commercial groves. Tree growth will be assessed through metrics such as stem diameter, tree height, and canopy volume by a plant physiologist. Yield data will be collected by SWFREC or the commercial grower. Rhizosphere samples for shotgun metagenomics will be collected biannually from each field trial. Microbial rRNA will be isolated from rhizosphere samples using the commercial PowerLyzer PowerSoil DNA extraction kits (MoBio Laboratories) and quantified using a Qubit Fluorometer (Invitrogen). Samples will be sent to the University of Florida Interdisciplinary Center for Biotechnology Research (ICBR) for shotgun metagenomics library preparation and sequencing. Data will be analyzed to examine changes to microbial community composition and function and correlations with environmental (soil type, rootstock, propagation method) and tree growth parameters. Several field trials are in the process of being established.
Target Audience
The target audience reached during this project included stakeholders (growers, production managers, farm operators, and industry personnel), researchers, extension personnel, students, interns, and the general public. The data from ongoing studies was presented at both grower and scientific seminars. These talked included the state-wide Florida Citrus Show and Citrus Expo, extension seminars, and the annual Soil Science Society of America meeting.
Changes / Problems
Nothing Reported
Training & Professional Development
Training and mentorship of a postdoctoral research associate, two MS students, and two PhD students has been provided by this project.
Dissemination Streams
Results from experiments conducted during this project were presented to citrus growers, industry, and extension personnel at the Citrus Expo (Ft. Myers, FL) and extension seminars for Polk County and Southwest Florida. In addition, results from these experiments were presented to UF Master Gardner's in Broward County and used for Florida Certified Crop Advisor certification sessions.?
Next Reporting Steps
Nothing Reported
Target Audience
The target audience reached during this period included stakeholders (growers, production managers, farm operators, and industry personnel), researchers, extension personnel, students, interns, and the general public. The data from ongoing studies was presented at both grower and scientific seminars. These talked included the state-wide Florida Citrus Show and Citrus Expo, extension seminars, and the annual Soil Science Society of America meeting.
Changes / Problems
Nothing Reported
Training & Professional Development
Training and mentorship of a postdoctoral research associate and two MS students has been provided by this project.
Dissemination Streams
Preliminary data from experiments were presented to citrus growers, industry, and extension personnel at the Citrus Show (Ft. Pierce, FL), a citrus-focused podcast (All in for Citrus, produced by UF/IFAS), and extension seminars for Polk County citrus growers. In addition, results from these experiments have been presented to UF Master Gardner's in Broward County, and used for Florida Certified Crop Advisor certification sessions. Data was also presented at the Soil Science Society of America annual meeting.
Next Reporting Steps
Nothing Reported
<br><br>
<br>What was accomplished under these goals? Impact: Results from a field trial examining the impact of commercially available soil amendments on the soil microbial community of citrus was recently submitted for publication in the journal Trees. A multi-year field trial in a commercial citrus grove is currently underway examining the influence of compost amendments on the soil microbial community and tree health. Objective 1: Greenhouse trials examined the influence of amending soils with biological soil crusts, naturally occurring consortia of bacteria, fungi, archaea, lichens, and moss, on citrus seedlings. These trials have been completed by a PhD graduate student and results are currently being prepared for publication. Studies continue to examine the interaction between rootstock propagation, soil type, and the soil microbial community composition. Objective 2: The results from a multi-year project to examine the impact of soil amendments on microbial communities of mature commercial citrus soils have been submitted for publication. In addition, a publication examining the relationship between core and functional microbiomes of different citrus rootstocks, in addition to other crops, has been submitted for publication. A field project examining the interactions between compost, rootstock genotype, and soil microbial communities of newly planted trees recently began the second year. Data from year 1 of the trial are still being analyzed. <br><br><b>Publications</b><br>
Target Audience
The target audience reached during this period included stakeholders (growers, production managers, farm operators, and industry personnel), researchers, extension personnel, students, interns, and the general public. The data from ongoing studies was presented at both grower and scientific seminars. These included talks at the state-wide Florida Citrus Show and a Citrus Soil Health Field Day, a citrus podcast produced by UF/IFAS, and presentations at the annual Soil Science Society of America meeting.
Changes / Problems
Nothing Reported
Training & Professional Development
Nothing Reported
Dissemination Streams
Preliminary data from experiments were presented to citrus growers, industry, and extension personnel at the Citrus Show (Ft. Pierce, FL), the Citrus Soil Health field day (Howie-in-the-Hills, FL), a citrus-focused podcast (All in for Citrus, produced by UF/IFAS), and seminars at the UF/IFAS Southwest Florida Research and Education Center. Data was presented at the Florida State Horticulture Society meeting, and the annual Soil Science Society of America meeting.
Next Reporting Steps
Nothing Reported
<br><br>
<br>What was accomplished under these goals? Impact: One field trial examining the impact of soil amendments on the microbial community of citrus soils was recently completed, and the last data collected is currently being analyzed. Preliminary data was presesnted to citrus growers and other industry personnel at the Florida Citrus Show in Ft. Pierce, FL and a Citrus Soil Health Field Day. Objective 1: Greenhouse trials, in collaboration with local citrus nurseries, looked at the impact of different soil types on citrus rhizosphere microbial community composition. A Master's graduate student conducted this research, and it was presented at the Florida State Horticulture Society meeting. This work has also been accepted for publication in the Proceedings of the Florida State Horticulture Society. Studies continue to look at interaction between rootstock propagation, soil type, and the soil microbial community composition. Objective 2: Field experiments from a multi-year project to examine the impact of soil amendments on the soil microbial communities of mature commercial citrus have recently been completed. The last data points are being analyzed, and publications are in preparation. A new field project was recently started to look at the interaction between compost, rootstock genotype, and the soil microbial community of newly planted citrus. <br><br><b>Publications</b><br>
Target Audience
The target audience reached during this period included stakeholders (growers, production managers, farm operators, and industry personnel), researchers, extension personnel, students, interns, and the general public. Data from ongoing studies was presented at both grower and scientific seminars. These included talks at the Citrus Show and Citrus Expo, two state-wide citrus industry meetings, as well as seminars at the UF/IFAS Tropical REC and Everglades REC, and a presentation at the Penn State Phytobiomes Symposium.
Changes / Problems
Nothing Reported
Training & Professional Development
Nothing Reported
Dissemination Streams
Preliminary data from experiments were presented to citrus growers and industry and extension personnelat the Citrus Expo (August, Ft. Myers, FL), and the Citrus Show (January, Ft. Pierce, FL). Preliminary data was also presented at research conferences, including the Penn State Phytobiomes Symposium in June.
Next Reporting Steps
Nothing Reported
<br><br>
<br>What was accomplished under these goals? Impact: Field experiments to examine the impact of soil amendemnts on the microbial community of citrus soils were continued in multiple groves. Preliminary data was presented to citrs growers and other industry personnel at two large citrus industry conferences: the Citrus Show (Ft. Pierce, FL - January) and the Citrus Show (Ft. Myers, FL - August). Objective 1: Greenhouse trials in collaboration with local citrus nurseries were begun to look at the impact of different soil types on ctirus rhizosphere microbial community composition. A graduate student is assisting with this project. In addition, an additionalgreenhouse experiment was performed as an initial screening/testing procedure on the efficacy of additional soil amedment products to improve plant growth and change the soil microbial community. A postdoctoral research associate assisted with this project. Both trials will conclude in the next several months. Objective 2: Experiments continued in the field to asess the impact of soil amendments on the soil microbial communities of citrus. Data has been collected from field trials examining the impact of amendments on mature citrus in two different commercial groves. The first set of data has been collected from anadditional trial examining the interaction of propagation method, rootstock genotype, and soil type. Data is still being analyzed and collected for both trials, as these are multi-year projects. <br><br><b>Publications</b><br>
Target Audience
The target audience reached during this period included industry stakeholders (growers, production managers, farm operators, industry personnel), researchers, extension personnel, students, interns, and the general public. Data from ongoing studies was presented at both grower seminars and scientific conferences. These included a talk for citrus growers on July 26 at the UF/IFAS Southwest Florida REC and an oral presentation at the 2017 American Society for Horticultural Sciences in September.
Changes / Problems
Nothing Reported
Training & Professional Development
Nothing Reported
Dissemination Streams
A seminar in collaboration with the plant physiologist was organized and held for local citrus growers in July 2017. This seminar provided information on the current knowledge of soil microbial amendments in agriculture and citrus, and preliminary data from greenhouse trials. Posters with information on the ongoing experiments were also presented at the local citrus show in August.
Next Reporting Steps
Nothing Reported
<br><br>
<br>What was accomplished under these goals? Impact: In the first year of this project, experiments were started to begin the examination of soil amendments in citrus. A seminar was organized and held for over 60 local citrus growers, where information on our current knowledge of soil microbial amendments and citrus was presented. Objective 1: Examine the effect of soil amendments on citrus seedlings and different citrus propagation methods under greenhouse conditions. These initial trials will be used to screen different amendments for those that have the greatest effect on the overall soil bacterial and fungal diversity and plant growth (including root growth). Trials were begun in collaboration with local citrus nurseries and tissue culture companies. A graduate student was recruited for start in Fall 2017 to work on this project. Preliminary data has been collected for several citrus rootstocks. Plans are being made for the next phase of greenhouse trials. Objective 2: Examine the impact of soil amendments on the soil microbial community and functional groups of non-affected and HLB-affected citrus in relation to soil type, rootstock, and tree age. Working with a plant physiologist, this data will be correlated with the impact of these amendments on the tree health and productivity. Together, this will provide information on whether changes to the soil microbial community, if they occur, directly impacts the health and productivity of citrus. Experiments were begun both in the greenhouse and in field trials to assess the impact of soil amendments on the soil microbial community of citrus. These trials involve four different rootstocks, multiple tree ages, and trees under different management practices. Data has been collected for two time points: prior to treatment and six months after the first treatment application. Data is still being analyzed and collected, as this is a multi-year project. <br><br><b>Publications</b><br>