Progress 02/01/24 to 01/31/25
Outputs
Target Audience:The primary target audience includes forest industry and nonindustrial private landowners. We delivered science-based information derived from this research. Results are presented directly to stakeholders through in person and online workshops. Continuing education credits for registered foresters have been offered along with the presentations. Changes/Problems:It took some time to hire grad students at VT, so a NCE will be necessary to finish out the project. Based on current results, we have less confidence in the microdialysis method as it appears to need to be calibrated for each soil type, making it a less desirable method for predicting P carryover and response to fertilization. We plan to reallocate some analysis funds to extend the work of the PhD student working on fungal microbiome analysis. A budget adjustment request will be forthcoming once we finish analyzing data currently in hand. What opportunities for training and professional development has the project provided?Ben Rose presented a summary of his work at Forest Productivity Cooperative 2024 Contact Meeting near Yulee, FL to ~35 forestry professionals. Ben Rose was also given the opportunity to spend 3 weeks in Florida in Dec 2024 with Rayonier (home of the first two intensive P carryover sites) to learn silvicultural operations top to bottom while conducting measurements and field work. He interacted with all facets of forest management and was able to speak to many different operational professionals. He found this to be an invaluable experience. Ben was received travel funding through the department to spend time in summer 2024 to visit scientists in Sweden to learn new techniques for fungal microbiome analysis. He interacted with top scientists in the field and cooperated on a project that he will receive coauthorship on the publication. He brought back many new skills to aid in P carryover data analysis. Jacob Hackman, PhD graduated from the project has begun as an Assistant Professor of Extension at Univ of Arkansas. He continues to work on the project in presenting results to forest industry and providing workshops to large industrial landowners and small private forest landowners. We continue to train Dr. Jacob Hackman in presentation skills and delivery (e.g. Contact Meeting in Yulee, FL) and how to provide workshops (FIA/AFM workshop in Louisiana, Sept 2024). As the electricity went out during presentations in Louisiana, Dr. Hackman practiced giving a presentation without the aid of power point, and provided field-based presentations of P carryover work. How have the results been disseminated to communities of interest?Our team visited large forest industry, small private landowners, and at several scientific meetings. FPC 2024 Contact Meeting near Yulee, FL. Study site tour and data review for ~90 forestry professionals by Jacob Hackman. Manulife Member visit 2024. Presented results from P carryover study to 4 company people. BTG Member visit 2024. Presented results from P carryover study to 15 company people. FIA/AFM Member visit 2024. Presented results from P carryover to 17 company people. Rose BD, Hackman J, Carter D, Strahm B, Garcia K, and Cook RL. June, 2024. The role of ectomycorrhizal fungi in the long-term management of Pinus taeda phosphorus fertility in intensive silviculture. 26th International Union of Forest Research Organizations World Congress. Stockholm, Sweden. David Enemo, Dan Hong, Dave Carter, and Brian Strahm. Unlocking Phosphorus: The Key Roles of Iron and Magnesium in Boosting Availability in Southern Loblolly Pine Plantations. Soil Science Society of America annual meeting. San Antonio, TX. November 10-13, 2024. Hong, D.S., J.M. Albaugh, D.R. Carter, and B.D. Strahm. Validity of the Diagnosis and Recommendation Integrated System (DRIS) for Diagnosing the Nutritional Status of Loblolly Pine and When to Use It. 2024 ASA, CSSA, and SSSA International Annual Meeting, San Antonio, TX, November 2024. Hong, D.S., D.R. Carter, and B.D. Strahm. Effects of fertilization and substrate quality on phosphorus dynamics in loblolly pine plantations in the southeastern US. 2024 ICTAS Doctoral Scholar Research Symposium, Blacksburg VA, March 2024. What do you plan to do during the next reporting period to accomplish the goals?Obj 1) Evaluate abiotic solid-solution phase dynamics of P as measured by simulated mass flow and diffusion, selective dissolution analysis to characterize reactive secondary minerals, and fractionation of P sub-pools associated with those minerals to determine how fertilizer inputs from previous rotation applications interact with soil characteristics to influence bioavailability, Soil samples collected during the summer of 2024 are currently undergoing laboratory analysis for sorption controls on P to analyzethe complex homeostatic interactions at the soil solution-mineral interface and their implications for tree growth metrics (Obj 3). Measurements of exchangeable P were taken with anion exchange resin probes installed at a second rotation P carryover site in North Carolina. The results of the resin probe measurements will be compared to Mehlich III soil P measurements collected at the same sites. Similarly, microdialysis measurements of diffusive P in soil solution from multiple soil horizons at two installed second-rotation sites in Florida and Georgia will be compared with Mehlich III soil P extractions from the same horizons and sites. These method comparisons will help determine how informative each method can be as an efficient predictor of foliar P concentration or tree growth responses. Based on the results of this method comparison, soil chemistry assays will be deployed to determine the availability and forms of soil P and link biological activity to soil chemical characteristics. Obj 2) Characterize how the fungal microbiome and mycorrhizal biomass are affected by previous rotation and current rotation fertilization to identify specific fungal taxa known to accumulate and exchange P with loblolly pine DNA will be extracted from soil samples collected in 2024. Targeted DNA fragments will be sequenced and analyzed to determine fungal community composition and identify specific taxonomy of ectomycorrhizal and saprotrophic fungi. The data will be analyzed with respect to carryover P treatments in previous rotations and P fertilizer additions in the current rotation to determine the impact of these treatments on fungal diversity and the relative dominance of specific fungal ecological guilds. Obj 3) Evaluate abiotic and biotic influences on nutrient acquisition and growth response of loblolly pine in the field and under controlled laboratory conditions Fungal community data will also be compared to measurements of soil P availability, foliar P concentrations, and growth response to identify dominant indicator species or species assemblies whose abundance is correlated with increased P availability or improved tree growth and nutrient uptake. Two more studies - one in TX and one in FL - are planned for installation in 2025 for tree measurements.
Impacts
What was accomplished under these goals?
The issue this project addresses is the ability to predict under what circumstances fertilizer P applied in one rotation of loblolly pine will remain available in the following rotation. Results will help forest managers and landowners to make better management decisions in loblolly pine plantations by either not applying P fertilizer when it is not necessary or by recommending P fertilizer when it is required, improving both environmental and economic outcomes. A better understanding of the drivers of P carryover is required to help improve these management decisions. Regarding each specific objective: 1) Evaluate abiotic solid-solution phase dynamics of P as measured by simulated mass flow and diffusion, selective dissolution analysis to characterize reactive secondary minerals, and fractionation of P sub-pools associated with those minerals to determine how fertilizer inputs from previous rotation applications interact with soil characteristics to influence bioavailability, Investigation of existing soil data reveals that interactions between Fe and Mg significantly influence P availability, accounting for 30-65% of its variance and exhibiting distinct soil depth-dependent dynamics. These findings have shaped our study on the abiotic, chemical controls of P to better understand the underlying processes and site-specific interactions across treatments, with the goal of improving site management strategies.Soil samples collected during the summer of 2024 are currently undergoing laboratory analysis, with complete results expected by the end of 2025. Foliage and litter decomposition are under investigation to assess soil nutrient cycling and foliar reabsorption.To quantify the effects of carryover P and different rates of fertilization on foliar resorption in young loblolly pine plantations in the southeastern US that differ in age and soil characteristics, green foliage was collected mid- to late-August from 14 plots (7 treatments x 2 replicate plots) in four RW28 sites (280601, 282401, 284201, 284501). Leaf litter was collected in traps mid- to late-November and prepared into a series of ~ 450 litterbags that will be deployed at each site and collected at intervals from 3-24 months to assess how P carryover is affecting current nutrient cycling and availability. Preliminary work by another PhD student, Maria Higuita, led to another successful USDA grant proposal to assess the impact of synthetic fungal communitiesunder lab conditions on P uptake by loblolly pine. The question is to see if loblolly pine grows better with single or multiple fungi present, i.e. do the fungi each play a slightly different role contributed. Two new PhD will be brought on under that new USDA proposal, with Dr. Kevin Garcia (Co-PI on this grant) as the lead PI. 2) Characterize how the fungal microbiome and mycorrhizal biomass are affected by previous rotation and current rotation fertilization to identify specific fungal taxa known to accumulate and exchange P with loblolly pine, Soil and root samples were collected for DNA sequencing and microbiome analysis from 10 second-rotation P Carryoversites in VA, NC, GA, FL, AR, AL, 2 post-harvest sites (not yet planted)in FL and TX, and 3 pre-harvest sites (first rotation, baseline data) in AL, LA, and NC. We included more sites than originally proposed as we were able to stretch our goals in sample collection. DNA sequence data was analyzed from a subset of soil samples collected during the first rotation (prior to second rotation P carryover trial establishment), along with sequences from soils sampled at three second-rotation sites. Sequence results show that fungal community compositions are significantly different among different sites, and these differences appear to be strongly influenced by soil characteristics. Distinct assemblies of dominant pine-associated ectomycorrhizal fungi were identified according to soil drainage and texture classifications. 3) Evaluate abiotic and biotic influences on nutrient acquisition and growth response of loblolly pine in the field and under controlled laboratory conditions. Two new studies were installed in 2024 - one in GA and one in AR. This brings the total number of installations to 8. The six established sites were measured for height, DBH or RCD, and HTLC. Routine annual tree measurements were also taken at three second-rotation sites in GA and FL. Due to issues with DNA sequencing from archived soils, responses to fertilization treatments were unclear from our preliminary subset, hence the new collection of samples. However, the observed differences in baseline fungal community among soil types suggest that response to fertilization may also vary by soil type, emphasizing the need for corroborating data from multiple sites to confirm interpretations of initial observations. Basal area growth rate is showingstrong associationwith foliar N, P, K, and S, but height and diameter at breast height (DBH) were more closely correlated with foliar Mg and Ca.
Publications
- Type:
Peer Reviewed Journal Articles
Status:
Published
Year Published:
2024
Citation:
Hackman, J., Woodley, A., Carter, D., Strahm, B., Averill, C., Vilgalys, R., ... & Cook, R. (2024). Fungal biomass and ectomycorrhizal community assessment of phosphorus responsive Pinus taeda plantations. Frontiers in Fungal Biology, 5, 1401427.
- Type:
Peer Reviewed Journal Articles
Status:
Published
Year Published:
2024
Citation:
Hackman, J., Cook, R., Strahm, B., Carter, D., Woodley, A., Garcia, K., ... & Campoe, O. (2024). Pinus taeda carryover phosphorus availability on the lower Atlantic Coastal Plain. Forest Ecology and Management, 555, 121701.
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Progress 02/01/23 to 01/31/24
Outputs
Target Audience:The primary target audience includes forest industry and nonindustrial private landowners. We delivered science-based information derived from this research in the following activities: 1) Jacob Hackman, PhD now graduated fromthe project, delivered a 20 minpresentation to forest industry (75 in attendance) a the Forest Productivity Cooperative Annual Meeting in Blacksburg NC (Aug2023); through his PhD defense (~30 in attendance including forest industry in May 2023); and at a Fall contact meeting in Jekyll Island, GA (~20 in attendence, Nov 2023, 3) Presentation of preliminary results directly to forest industry through workshops including for continuing education credits. Dr. Cook presented to RMS in Wilmington, NC in Dec 2023 (1 hour presentation, 4 in attentendence), BTC in Colombia, SC (1 hour field presentation at a P carryover site, 12 in attendence), Camcore at Hofmann Forest NC in Oct 2023 (~30 in attendence), AFM at Panama City Beach, FL (~35 in attendence, 1 hour presentation), JD Irving in Bangor ME in Sept 2023 (~10 in attendence),Molpus Timberland Management in Valdosta, GA in Dec 2023(1 hour field presentation, 22 in attendance). Changes/Problems:It took some time to recruit and start the new phd students, so a NCE may be required. We will also be asking for a rebudget as we have already spent almost all the supplies out of the NCSU budget and may need to reallocation from other lines. What opportunities for training and professional development has the project provided?Jacob Hackman, PhD student now graduated from the project, has published two papers from his PhD concerning the evaluation of soil tests and their correlation with growth response. Dan Hong and David Enemo, PhD students at VT are actively developing their protocols to assess the relationship between forest floor quality and quantity and P availability, and P dissolution from soils across the experiment. 2) Jacob Hackman has submitted revisions to his PhD paper regarding the influence of P treatment at two sites on the fungal microbiome. Jacob Hackman isnow workingas a post doc in our lab and interviewing with potential employers. He interviewed for an academic position at University of Georgia and currently has an interview for University of Arkansas. How have the results been disseminated to communities of interest?Yes, results have been disseminated through several presentations, the FPC Annual Meeting in Aug 2023, the Fall Contact meeting in Nov 2023, and many field visits with forest industry in the fall of 2023 (Molpus, AFM, RMS, BTG, Arborgen, Jordan Lumber, JD Irving, Camcore). Forest industry stakeholders were also present online for the dissertation defense of Jacob Hackman's work that is detailed above. Poster presentations of the results include: David C. Enemo, Daniel S. Hong, David Carter, Rachel Cook, and Brian D. Strahm. 18-year Effects of Nitrogen and Phosphorus Fertilization on Selected Soil Chemical Properties under Loblolly Pine Plantations in the Southeastern United States. 14th North American Forest Soils Conference. Eugene, OR. July 16-20, 2023. Daniel S. Hong, David C. Enemo, Rachel L. Cook, David R. Carter and Brian D. Strahm. Loblolly pine responses to carryover phosphorus fertilization in the southeastern US. 14th North American Forest Soils Conference. Eugene, OR. July 16-20, 2023. David C. Enemo, Daniel S. Hong, David Carter, Rachel Cook, and Brian D. Strahm. 18-year Effects of Nitrogen and Phosphorus Fertilization on Selected Soil Chemical Properties under Loblolly Pine Plantations in the Southeastern United States. Forest Productivity Cooperative Annual Meeting. Blacksburg, VA. August 16-17, 2023. What do you plan to do during the next reporting period to accomplish the goals?We have four phd students (two students funded with leveraged support) actively working on each of the objectives for the project. After the first three publications, we have another one in prep that will be submitted this year. We are about to install two more field trials and are quickly accumulating data from our network of trials across the southeast.
Impacts
What was accomplished under these goals?
The issue this project addresses is the ability to predict under what circumstances fertilizer P applied in one rotation of loblolly pine will remain available in the following rotation. Results will help forest managers and landowners to make better management decisions in loblolly pine plantations by either not applying P fertilizer when it is not necessary or by recommending P fertilizer when it is required, improving both environmental and economic outcomes. Regarding each specific objective: 1)Microdialysis, a new method taken from neuroscience, uses tiny probes to simulate the process of mass flow and diffusion of nutrients in soils. These are the primary ways that plants take up nutrients. We used microdialysis on soils collected from plots treated in the field with phosphorus at varying levels in the last rotation (0, 40, 60, and 121 kg/ha P), and a subset re-fertilized at establishment (40 kg/ha P in the previous rotation and 45 kg/ha P in the current rotation), to assess the availability of phosphorus to the trees. We correlated the "available" P, as measured by microdialysis to tree growth to look for relationships. In the clay soil, we found the highest concentrations in the highest fertilizer treatment one year after establishment but no differences among the other treatments. In the sandy soil, the greatest difference from year 0 to year 1 was also in the highest (121 kg/ha P) treatment. We also inserted these probes into the tree itself to evaluate if we could see actual nutrient uptake in real-time within the tree and if this was affected by different levels of residual nutrients from fertilizer applications. Due to rates of evapotranspiration, sunny days pulled much more water through the tree, but when we accounted for those differences, we saw weak evidence (p = 0.23) that P fertilizer treatment affected P concentration in the tree, but indicated that future work to investigate this further would be worthwhile. Great control of when data is collected based on weather would likely help establish a stronger relationship. A paper has recently been published further detailing these results (Hackman et al., 2023 in Plant Soil). 2)We buried "fungal capture bags," collected samples from tree roots (the rhizosphere), and samples from bulk soil to assess methods of collecting fungal communities with two of the first sites to be installed (a poorly drained clay soil - an Alfisol, and a somewhat poorly drained sandy soil - a Spodosol). Because of the intensity and cost of running fungal microbiome analysis, we selected a subset of plots (No fertilizer, 40 kg/ha P in the previous rotation, 121 kg/ha P in the previous rotation, and 40 kg/ha P in the previous rotation plus 45 kg/ha P in the current rotation) to assess the effect of carryover and newly applied P fertilizer on the fungal community. First, we found in the mesh bags, that bags "baited" with P rather than just pure sand, had greater amounts of fungal biomass inside. These bags have a very fine mesh that allows fungi to enter but not tree roots. So we determined that the fungi do seek out the P in the bags. We buried these bags before the previous rotation was harvested (in 2018) and through new plantation establishment up to 2022. Interestingly, there was more difference in fungal biomass among treatments (with the control having more fungal biomass in bags) in the mature plantation before harvest than in later samplings. We suspect this may be because the ECM fungal population (those that are symbiotic with loblolly pine) likely declines rapidly once the trees are harvested (since they depend on the trees for sugar). It will be interesting to see in future mesh bag sampling if the differences across P fertilizer treatments return with time. We also looked at the diversity of the fungal community among treatments at the two sites. Contrary to what many might expect, the treatment that received fertilizer had greater fungal diversity than the control, but only at the clay site. At the sandy soil site, there were no differences due to P fertilizer treatment in diversity. So we can conclude, so far, that P fertilization does not negatively affect fungal diversity. Finally, we looked at the relative abundances of all fungal species and found that site (clay vs sandy soil) was a much bigger driver than P fertilizer treatment. Although when we looked just at the ECM fungi, there was not as much difference between sites. These results have been submitted in a publication to the journal Mycorrhizae and is currently under review. Next, Ben Rose, the new PhD student on the project is systematically sampling all the field sites to characterize the differences across all sites and treatments. Four sites have currently been sampled and the rest will be sampled this winter. This analysis will expand the original analysis conducted on the first two sites. Additionally, another new PhD student, Maria Higuita, is assessing the impact of synthetic fungal communities under lab conditions on P uptake by loblolly pine. The question is to see if loblolly pine grows better with single or multiple fungi present, i.e. do the fungi each play a slightly different role. Preliminary data with one vs two fungi suggest that two fungi may have a synergistic effect on nutrient uptake. 3)In field conditions at the first two sites established on contrasting soils (a clay soil and a sandy spodic soil), at year 2 we already are seeing significant differences in growth due to treatments (amount of P applied in the previous rotation and some plots receiving additional fertilization at planting). So far the Mehlich 3 soil test helped to predict height growth in the clay soil but not in the sandy soil. Interestingly, the O-horizon (also known as the forest floor) from the previous rotation also appears to be a good predictor of age 2 height of trees. Plots that received more fertilizer in the previous rotation also tended to have greater O horizon, meaning that the forest floor appears to be a reserve of nutrients released to the next rotation. Interestingly, so far year 3 measurements suggest that as long as at least 50 lbs of P were applied (either in the previous rotation or as fertilizer in the current rotation). These results have been accepted for publication in the journal Forest Ecology and Management. In our microdialysis experiments in lab conditions, we tested soils from the first two field sites to be established in a new plantation and found that in the clay soil there was a positive relationship between diffusive (microdialysis) P concentrations and tree heights at age 2 but no relationship in the sandy soil. There was also much more diffusive P in soil solution in the sandy soil, likely because there are fewer sites for it to "attach." Furthermore, because these samples were taken from the surface soil (top 15 cm), we decided to sample soils from deeper in the soil profile in case more P was concentrated at greater depths. Those samples have just finished being collected in the lab and are now being processed for diffusive P concentration. These two soils represent two very common soils planted in the southeast but there are many more sites to analyze with different soils. More samples are being taken with every new site installation. Five sites have been installed (meaning the former rotation has been harvested and new trees have been planted) and trees are getting measured every winter. Three more sites are still to be installed. Additionally, Jacob Hackman is now working as a postdoc and using O horizon and soil data collected previously in 2013 down to one meter to assess the abiotic influences (texture, Al Fe oxides, etc) on the build up of P in the soil horizons and any relationships with current tree growth.
Publications
- Type:
Journal Articles
Status:
Awaiting Publication
Year Published:
2024
Citation:
Hackman, J., R.L. Cook, K. Garcia, D. Carter, A. Woodley, B. Strahm, T.J. Albaugh, R. Rubilar, O. Campoe. Pinus taeda Carryover Phosphorus Availability on the Lower Atlantic Coastal Plain. Forest Ecology and Management. In press.
- Type:
Journal Articles
Status:
Published
Year Published:
2024
Citation:
Hackman, J., R.L. Cook, B. Strahm, D. Carter, A. Woodley, and K. Garcia. Using microdialysis to assess soil diffusive P and translocated sap flow P concentrations in Southern Pinus taeda plantations. Plant and Soil. Published online 05 Jan 2024
- Type:
Journal Articles
Status:
Under Review
Year Published:
2024
Citation:
Hackman, J., R.L. Cook, K. Garcia, A. Woodley, D. Carter, B. Strahm, C. Averill, R. Vilgalys. Fungal Biomass and Ectomycorrhizal Community Assessment of Phosphorus Responsive Pinus taeda Plantations. Mycorrhiza. Under review.
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Progress 02/01/22 to 01/31/23
Outputs
Target Audience:The primary target audience includes forest industry and nonindustrial private landowners. We delivered science-based information derived from this research in the following activities: 1) the PD provided a lecture on P carryover and explanation of the experimental design in FOR 713 Advanced Silviculture to 7 graduate students, 2) Jacob Hackman, PhD candidate on the project, delivered a 20 min presentation to forest industry (75 in attendance) a the Forest Productivity Cooperative Annual Meeting in Raleigh NC (Aug 10, 2022),3) Presentation of preliminary results directly to forest industry through workshops including for continuing education credits. Dr. Cook presentedto Molpus Timberland Management, Lufkin, TX Oct 26, 2022 (1 hour field presentation, 22 in attendance), Potlatch Deltic in Prattville, Alabama Dec 8, 2022 (10in attendance), Campbell Globel in Wilmington, NC Nov 3, 2022 (9in attendance), and Rayonier in Kinder, LA Nov 17, 2022 (5 in attendance). Changes/Problems:It took almost a year to recruit, identify and start two new PhD students at Virginia tech. Both PhD have started as of Jan 2023 (one year after grant start date). This will likely contribute to a need for a no-cost extension in the future. At NC State, a former graduate student, involved in all the preliminary work and grant writing should graduate Spring 2023 and a new PhD with excellent fungal microbiome skills has agreed to start in the fall. What opportunities for training and professional development has the project provided?The PhD student on the project, Jacob Hackman, had the opportunity to work directly with Rayonier, one of the forest industry partners that hosts two field sites and learn about industry research opportunities. Additionally, the field skills he is developing and the work he has been performing helped land him an interview at another large university for a potential assistant professor position where he was able to present his work on P carryover and develop his professional interviewing skills. How have the results been disseminated to communities of interest?Yes, results were disseminated through Jacob Hackman's presentation at the Forest Productivity Cooperative annual meeting and are currently in near final draft form for a paper submission. What do you plan to do during the next reporting period to accomplish the goals?The manuscripts Jacob Hackman is preparing to finalize his dissertation include 1) comparison of soil mehlich 3 extractions, resin probe extractions, and tree growth, 2) microdialysis P availability, and 3) fungal microbiome from the first two sites that have been installed, planted, and most thoroughly measured. We will also bring on a new PhD student in Fall 2023 to replace Jacob as the primary graduate student at NCSU.
Impacts
What was accomplished under these goals?
Regarding each specific objective: 1) Jacob Hackman (phd student) has just finished the microdialysis extractions to asses solid-solution phase P dynamics due to carryover vs recently fertilized P and samples are currently being analyzed. Resin Probe P from two sites (FL, GA, and NC) are complete and results are currently in draft form for a manuscript. Additionally, another siteis being installed this winter. 2) Fungal biomass has been shown through fungal bags to preferentially target bags baited with phosphorus and we are finding some differences in biomass among treatments. Data are currently under review and more fungal bags are being prepared to be deployed. Microbiome results have just arrived and are currently under analysis for the first two sites. 3) Measurements at the three intensive sites (NC, GA, and FL) have been taken for this winter and data will be analyzed with soil biotic and abiotic factors. Importantly, two new PhD students (one funded by VT along with the USDA graduate student) have started this fall and will begin on the P fractionation portion of the experiment and help with site installation and data collection. The former PhD working on the project should graduate this spring at NC State, and a new PhD student has been identified to replace him.
Publications
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