Feedstock Environmental Research

Carbon Sequestration With Short-Rotation Hybrid Poplar Production Compared With Agricultural Crops and Farm Woodlands

Research Funded by: U. S. Department of Energy, Office of Fuels Development through Oak Ridge National Laboratory

Project Manager: V. R. Tolbert, 865.574.7288, tolbertvr@ornl.gov

Performing Organization: USDA - Forest Service, North Central Research Station, Rhinelander, WI 54501

Principal Investigator: Jud Isebrands, 715.362.1116, jisebrands@fs.fed.us

Contract Number: DE-AI05-95OR22368

Contract Period: 12/96-12/00

Contract Funding:

FY99: $10,000

Objective: To quantify differences in soil carbon sequestration with production of hybrid poplar crops on agricultural lands in the North Central region compared with agricultural crops and farm woodlands.

Approach/Background: This research is quantifying differences in soil carbon sequestration with conversion from traditional agricultural crops to hybrid poplar compared with adjacent lands still in agricultural crop production and farm woodlands. Twenty sites established with hybrid poplar compared with adjacent farm woodlands of 80-100 years old, and agricultural crops across a variety of sites in MN, WI, ND, and IA were sampled to determine differences in soil carbon content in response to climate, soil types, and rotation age. Some of the thirteen hybrid poplar plantings established near Alexandria, MN in 1995 and 1996 as part of scale-up demonstration were sampled as part of this study. At each location, three samples were taken at 3 m distances from a set point from each treatment at each location. This project follows that of earlier work by Ed Hansen of the North-Central Forest Experiment Station.

Status/Accomplishments: Laboratory sample analysis of the 1998 samples has been completed and the data are being compared with that from the baseline sampling. The comparisons are showing that there is variability in response of different sites to conversion to tree crop production. The variability was attributed to the differences in site characteristics, differences in soil texture and depth, and to some extent cover type. In contrast to the results found by Hansen that soil organic carbon (SOC) decreased during the first 2-3 years following initial establishment, the results of this preliminary study show no differences in soil carbon during early tree crop establishment compared with that of adjacent agricultural crop lands.

In general, the comparisons of hybrid poplar planting, woodlands, and agricultural croplands showed that soil carbon storage decreased with depth while bulk density increased. The SOC within the upper 8 cm was approximately equal on the hybrid poplar and agricultural sites. On the sites with more mature trees, the surface layer bulk density was lower and had increased percent SOC compared with other cover types. There was no significant change in the quantity of SOC (g cm-3) in the soil within the upper 8 cm for the agricultural crop, forest, and hybrid poplar comparisons; there was significantly less SOC in the 8-32 cm depth on forested sites compared with the agricultural and poplar sites. The analyses to date show that there is significant variability in the data. Understanding the influence of soil texture and depth and increasing the number of samples will be required to decrease the within site variability and quantify changes in SOC. This understanding will increase the ability to quantify changes in soil carbon sequestration across a variety of sites in the North Central region.

Publications and presentations:

1. Isebrands, J.G., M.D. Coleman, C.H. Perry. 1999. Carbon sequestration of short rotation hybrid poplar in comparison with agricultural crops and mature forests in the North Central region. Presentation at the U.S. Poplar Council, Alexandria, MN, August 18-19, 1999.

Summary Date: March 2000

Development of Optimal Establishment and Cultural Practices for Switchgrass and Other Energy Crops: Environmental Studies

Research Funded by: U. S. Department of Energy, Office of Fuels Development through Oak Ridge National Laboratory

Project Manager: V. R. Tolbert, 865.574.7288, tolbertvr@ornl.gov

Performing Organization: Auburn University, Auburn, AL 36849-5145, www.auburn.edu

Principal Investigator: David Bransby, 334.844.3935, dbransby@acesag.auburn.edu

Contract Number: 19X-XY164C

Contract Period: 06/97B05/02

Contract Funding:

FY 1998: $20,000

FY 1999: $20,000

Objective: The goals of this research are (a) to study root and soil carbon dynamics for switchgrass when grown for energy, (b) to relate variation in switchgrass yield across commercial fields to changes in soil characteristics, and (c) to determine aggregate improvement in soil quality from growing switchgrass.

Approach/Background: Root and soil carbon dynamics of switchgrass are being monitored on several experiments at different locations and on different sites. These experiments include different varieties of switchgrass, different row spacings, and different harvest frequencies. Specifically, soil cores are being taken every 2-3 years to a depth of bedrock, or 3.3m. Measurements include root mass at different depths, carbon mineralization, microbial biomass carbon, carbon turnover, and organic carbon.

The relationship between yield and soil characteristics in commercial fields is being developed by harvesting 20 sample sites from two commercial fields for both yield, herbage composition and soil characteristics. These data will then be analyzed by regression analysis.

The aggregate improvement of soil from growing switchgrass for energy is being studied by determining the yields of corn, cotton and soybeans grown after switchgrass in a crop rotation, or on land that was previously fallow.

Status/Accomplishments: Soil and root samples were collected in 1998 and 1999, and are in the process of being analyzed. Preliminary data from these experiments indicated that although most of the roots are located in the top 15 cm of the soil profile, some roots extend as much as 3.3 m below the soil surface. Root biomass was dependent on soil type and variety of switchgrass: root mass for Cave-in-Rock switchgrass was 29.4 and 47.6% greater than for Alamo and Kanlow, respectively. Soil carbon had increased within 2 years of switchgrass establishment.

The height of cotton, soybeans and corn was 43, 20 and 14% greater when these crops were grown on plots previously in switchgrass, compared to plots that were previously fallow. However, crop yields did not mirror this pattern: there was no difference in cotton yield between switchgrass and fallow plots, but corn and soybean yields were 43 and 20% higher, respectively, for plots that had previously been in switchgrass.

Publications and Presentations:

1. Ma, Z., C. W. Wood and D. I. Bransby. Carbon dynamics subsequent to establishment of switchgrass. .In preparation.
2. Ma, Z., C. W. Wood and D. I. Bransby. Impacts of soil management on root characteristics of switchgrass. In preparation.

Summary Date: September 1999

Effects of Herbaceous and Woody Crops in Uptake, Release and Offsite Movement of Nutrients and Pesticides

Research Funded by: U. S. Department of Energy, Office of Fuels Development through Oak Ridge National Laboratory

Project Manager: V. R. Tolbert, 865.574.7288, tolbertvr@ornl.gov

Performing Organization: Department of Forest Resources, College of Natural Resources, University of Minnesota, St Paul St. Paul, MN 55108-6112

Principal Investigator: Kenneth N. Brooks, 612.624.2774, kbrooks@forestry.umn.edu

Contract Number: DE-AI05-95OR22368

Contract Period: 12/94-12/00

Budget:

FY98: $87,900

FY99: $80,000

Objective: To determine the effects of biomass energy crops (short-rotation hybrid poplar plantings and switchgrass) on subsurface water quantity and quality, and compare these effects to both traditional agricultural crops (wheat) managed under a typical fertilizer/pesticide regime, and naturally occurring forest stands.

Approach/Background: This research is quantifying differences in the capabilities of short-rotation woody culture (SRWC) plantings, switchgrass, and natural forest communities to modify the export of water and non-point source pollutants (e.g., nitrate, phosphorus, and pesticides) compared with traditional agronomic crops. The approach is to determine differences in chemical transport from natural mature forest communities and short-rotation hybrid poplar. Comparisons in chemical movement from hybrid poplar, switchgrass, and agricultural crops during establishment and throughout their production cycles, whether soil physical and chemical properties (including soil carbon) differ beneath these alternative land uses at the Oaklee research site and across a variety of sites in Minnesota, and whether in riparian systems, chemical export from natural forest communities, short-rotation hybrid poplar plantings, and switchgrass plantings differ.

Status/Accomplishments: Throughfall in 8 to 9-year-old short-rotation hybrid poplar plantings and 22 to 34-year-old natural mixed aspen stands is not significantly different. The hybrid poplar plantings and natural mixed aspen stands are contributing similar amounts of water to shallow ground water; the consumptive water use by the hybrid poplar plantings was similar to that of mature forest stands.

Nutrient export of total nitrogen and total dissolved phosphorus were not different between the 8 to 9 year-old hybrid poplar plantings and 22 to 34- year-old natural mixed aspen stands. Overall, nutrient export rates from the natural forest stands have been similar to those reported elsewhere for similar forest stands. A new, inexpensive passive capillary soil water sampler was designed as part of this study and has been shown to be effective to sample chemical migration through the soil.

Results from the 1998 sampling season indicated that short-rotation hybrid poplar plantings and switchgrass plots do not contribute pesticides to ground water during establishment. During the first year of establishment there were no differences in nutrient contribution to water in either shallow or deep lysimeters among the biomass crops and annual agricultural crops; these are currently being compared with native forest stands.

Publications and presentations:

1. Perry, C.H. 1998. Hydrologic impacts of short rotation woody crop production in northwestern Minnesota. Ph.D. Thesis. U. Minnesota, St. Paul.
2. Perry, C.H., K.N. Brooks, D.F. Grigal, J.G. Isebrands, and V.R. Tolbert. 1998. A comparison of nutrient export from short-rotation hybrid poplar plantations and natural forest stands. Pp. 1252-1261. BioEnergy 98: 8th National Bioenergy Conference.
3. Perry, C.H., R.C. Miller, and K.N. Brooks. Accepted for publication. Impacts of short-rotation woody crops on regional water yield. Forest Ecology and Management.
4. Josiah, S., H.M. Gregersen, E. Streed, C.H. Perry, and K.N. Brooks. In Press. The potential for integrating short-rotation woody crops into agroforestry systems and practices in the United States: A national assessment.
5. Perry, C.H., D.F. Grigal, J.G. Isebrands, and V.R. Tolbert. 1998. Carbon sequestration in northwestern Minnesota's agricultural landscapes. Abstract. Agronomy Abstracts 298.
6. Perry, C.H., R.C. Miller, and K.N. Brooks. 1998. Hydrologic implications of introducing hybrid poplars in Minnesota's farmlands. Presented at the International Conference on the Science of Managing Forests to Sustain Water Resources, Sturbridge, MA, November 9-11, 1998. International Union of Forestry Research Organizations / Society of American Foresters / National Association of State Foresters / USDA Forest Service
7. Perry, C.H., D.F. Grigal, J.G. Isebrands, and V.R. Tolbert. 1998. Carbon sequestration in northwestern Minnesota's agricultural landscapes. Invited Poster Presentation to the Annual Meeting of the Soil Science Society of America, Baltimore, MD, October 18-22, 1998. American Society of Agronomy.
8. Perry, C.H., K.N. Brooks, D.F. Grigal, J.G. Isebrands, and V.R. Tolbert. 1998. A comparison of nutrient export from short-rotation hybrid poplar plantations and natural forest stands. Presented at BioEnergy '98: The Eighth National Bioenergy Conference, Madison, WI, October 4-8, 1998. Great Lakes Regional Biomass Energy Program.
9. Perry, C.H., R.C. Miller, and K.N. Brooks. Accepted for publication. Impacts of short-rotation woody crops on regional water yield. Forest Ecology and Management.
10. Perry, C.H., R.C. Miller, K.N. Brooks, and D.F. Grigal. In review. A comparison of nutrient loading beneath short-rotation hybrid poplar plantations and mature aspen stands. Journal of the American Water Resources Association.
11. Perry, C.H., R.C. Miller, D.F. Grigal, and K.N. Brooks. In review. Design and performance of an inexpensive passive capillary soil water sampler. Soil Science Society of America Journal.
12. Perry, C.H., R.C. Miller, A.R. Kaster and K.N. Brooks. 2000 (in Press). Watershed management implications of agroforestry expansion on Minnesota's farmlands. Proceedings of Land Stewardship in the 21^st Century: The Contributions of Watershed Management. Tucson, Arizona.

Summary Date: September 1999

Environmental Impacts of Conversion of Cropland to Short-Rotation Biomass

Research Funded by: U. S. Department of Energy, Office of Fuels Development through Oak Ridge National Laboratory

Project Manager: V. R. Tolbert, 865.574.7288, tolbertvr@ornl.gov

Performing Organization: Department of Plant and Soil Science, Alabama A&M University P.O. Box 1208, Normal, AL 35762

Principal Investigator: David A. Mays, 256.858.4227

Contract Number: 90XSR706C

Contract Period: 3/95-10/00

Contract Funding:

FY 1998: $11,800

FY 1999: $70,000

Objective: This research is investigating the impact of conversion of agricultural land to short rotation woody (sweetgum) and herbaceous (switchgrass) perennial biomass crops compared with no-till corn for grain on soil erosion, runoff quality and quantity, groundwater quality, belowground storage of carbon and nitrogen and soil physical properties. If this and similar research at the Ames Plantation, University of Tennessee and Mississippi State University prove the feasibility of the concept, a market could develop for biomass crops from many thousands of under utilized acres of cropland that could also reduce net emissions of carbon dioxide.

Approach/Background: This research is addressing potential environmental concerns about energy crops before their wide-scale adoption occurs. Earthen berms were constructed around half-hectare replicated research plots of sweetgum with a cover crop (SWC), sweetgum without a cover crop (SWNC), switchgrass, and no-till corn for grain. In 1995. Rainfall, runoff, erosion, and infiltration within each of the eight plots has been monitored on an event basis since the project began. Productivity of the individual crops is determined annually.

Status/Accomplishments: Comparisons of tree crop productivity through 1997 showed that there was little difference between the SWC and SWNC. In 1999, SWC were shown to grow faster and have a greater current annual growth increment than SWNC. Initial runoff and erosion measurements (1995-1996) showed that by year two soil cover was well established on the switchgrass plots and that runoff from switchgrass was approximately the same as SWC and no-till corn. In 1998 and 1999, runoff from SWNC was consistently higher than the other treatments, particularly in the spring prior to leafout. Nitrate losses correspond to fertilizer application and were consistently higher from no-till corn in the spring in 1998 and 1999. Erosion from SWNC was approximately 1000 kg/ha through 1997 and less than 400 kg/ha from the other treatments. In 1998, erosion across all treatments was consistently less than 200 kg/ha after a soil cover or a litter layer developed on all treatments. Carbon sequestration significantly increased on the SWC, switchgrass, and no-till corn treatments but not SWNC over the first four years of growth.

A companion study to identify the effects of cover crop strip widths between rows and the type of cover on productivity show that both annual and legume cover crops reduced sweetgum growth below that of control plots without cover. By the 1999-growing season, trees with a crimson clover cover crop appeared to be more vigorous, had better leaf color and greater crown width. Data from 1999 and 2000 will be used to validate of refute these observations.

Publications and Presentations:

1. Malik, R.K., T.H. Green, D. Mays, G.F. Brown. 1999. Can cover crops be used in short-rotation, intensive-culture hardwood plantations to control erosion. In Press. Biomass and Bioenergy.
2. Tolbert, V. R., F. C. Thornton, J. D. Joslin, B. R. Bock, W. E. Bandaranayake, D. D. Tyler, D. Pettry, T. H. Green, R. Makik, A. E. Houston, S. Schoenholtz, M. Shires, L. Bingham, J. Dewey. 1998. Soil and water quality aspects of herbaceous and woody energy crop production: lessons from research-scale comparisons with agricultural crops. p. 1272-1281. Bioenergy98, Madison, WI, October 4-8, 1998.

Summary Date: September 1999

Implications of Using Corn Stalks as Bioenergy Feedstocks

Research Funded by: U. S. Department of Energy, Office of Fuels Development through Oak Ridge National Laboratory

Project Manager: V. R. Tolbert, 865.574.7288, tolbertvr@ornl.gov

Performing Organization: USDA-ARS, Agronomy Department, University of Nebraska, Lincoln, NE 68583-0915

Principal Investigator: James S. Schepers, 402.472.1513, jschepers1@unl.edu

Contract Number: Interagency Agreement DE-AI05-99OR-22761

Contract Period: 9/99-8/00

Contract Funding:

FY99: $175,000

Objective: The USDA ARS is working with the Bioenergy Feedstock Development Program to study both the short and long-term environmental implications of using corn stover or stalks as a biofuel.

Approach/Background: The project involves identifying environmental issues associated with stover removal and establishing a cooperative program drawing upon the expertise of researchers and facilities at field sites at approximately five locations in the upper mid-western region. Three tasks are planned as part of this approach: (1) Plan and conduct a stakeholder workshop to address issues related to corn stover and its removal from agricultural lands; (2) Review pertinent literature and prepare a draft manuscript for possible future publication. Describe the current status of both short- and long-term environmental implications of corn stover removal; and (3) Develop a detailed 5-year plan to prioritize and address issues associate with stover removal using input received from Task 1 stakeholders' workshop, as well as results from Task 2 literature review.

Status/Accomplishments: An initial review of the scientific literature was conducted by cooperating Oak Ridge National Laboratory researchers in FY99 to identify issues and as background for this project. A workshop involving researchers from ARS laboratories and field sites was planned and organized by ARS for early 2000. Researchers were given the opportunity to identify key issues and to suggest approaches and appropriate research to quantify both the near and long-term effects of corn stover removal on soil and water quality.

Publications and presentations:

1. Mann, L.K., Tolbert, V.R., and Cushman, J.H. Implications of using corn (Zea mays) as a feedstock for bioenergy production. Submitted.
2. Schepers, J.S. Environmental aspects of corn stover use for energy. BFDP Contractor's Workshop, Alexandria, MN, October 1999.

Summary Date: September 1999

Soil Organic Carbon Sequestration In Reclaimed Minelands in Ohio

Research Funded by: U. S. Department of Energy, Office of Fuels Development through Oak Ridge National Laboratory

Project Manager: V. R. Tolbert, 865.574.7288, tolbertvr@ornl.gov

Performing Organization: School of Natural Resources The Ohio State University Columbus, OH

Principal Investigator: Rattan Lal, 614.292-9069, lal.1@osu.edu

Contract Number: DE-A105-96OR22560

Contract Period: 9/97-10/2000

Contract Funding:

FY 1998: $10,000

FY 1999: $24,500

Objective: Soil aggregation is one of the processes leading to soil organic carbon (SOC) sequestration. A chronosequence study on reclaimed minesoils at 0-15 cm depth began in 1997 to determine the effects of reclamation duration and different management systems on accumulation of SOC in water stable aggregates (WSA).

Approach/Background: Increased soil aggregation leads to increased C sequestration; increased SOC content also enhances soil aggregation. Understanding relationships between SOC content and aggregation and the effects of time on the relationship are important steps to identifying and adopting strategies to enhance SOC sequestration. This research is using a chronosequence of lands with reclamation durations ranging between 0 and 25 years for the pasture and forest treatment with topsoil addition and between 30 and 50 years for the pasture and forest treatment without topsoil application. Control sites were at least 60 years old.

Status/Accomplishments: Studies in FY98 showed the potential to sequester SOC through reclamation of mine soils. Reclamation treatments included establishing forest and pasture with and without topsoil application. The results indicated beneficial effects of vegetative cover establishment on SOC pool In FY99 comparisons showed that total WSA increased from 25% to 85% within 25 years for pasture and 65% to 90% for the forest treatments with topsoil application. The WSA remained fairly constant at 60% to 65% for both treatments without topsoil application compared with a WSA of 75% for undisturbed pasture and 70% for undisturbed forest. Over the reclamation duration, both pasture and forest treatments with topsoil application achieved total WSA that were comparable to undisturbed pasture and forest; the treatments without topsoil application have yet to achieve total WSA comparable to the undisturbed sites.

The 5-8 mm size fraction of the WSA formed the largest proportion in all treatments and had the highest SOC content (12 and 14 gCkg^-1 for the undisturbed pasture and forest treatments, respectively). After 25 and 21 years, the SOC content in the 5-8 mm size fraction was 12 gCkg ^-1 for pasture and 15 gCkg^-1 for forest sites reclaimed with topsoil application and 11 and 4 gCkg respectively for ^-pasture 40 years and forest 50 years after reclamation without topsoil application.

The high correlations between WSA and SOC (0.95 and 0.99) suggest that improved aggregation over the reclamation duration and increased SOC content were complementary processes. Aggregation improved over time, thus increasing the SOC sequestration capacity. The largest SOC content was observed in 5-8 mm aggregate size fraction suggesting the formation of stable soil structure over time.

Publications and Presentations:

1. Akala. V. and R. Lal. 1999. Mineland reclamation and soil organic carbon sequestration in Ohio. pp. 322-331. Proceedings 16^th Ann. Meeting, Am. Soc. Surface Mining and Reclamation, Aug 13-19, Scottsdale, AZ.
2. Akala, V. A. and R. Lal. 1999. Soil organic carbon enhancement in graded and ungraded reclaimed mineland under forest and pasture in Ohio. Under review for the proceedings of the International Soil Conservation Organization Conference, West Lafayette, May 23-26.

Summary prepared: September 1999

Southeastern Sustainability Research: Subsurface Nutrient Movement From Intensively Managed Tree Crops

Research Funded by: U. S. Department of Energy through the Oak Ridge National Laboratory

Project Manager: V. R. Tolbert 865.574.7288, tolbertvr@ornl.gov

Performing Organization: Oar Ridge National Laboratory

Principal Investigator: Donald E. Todd, Jr. 865.574.7344, toddde@ornl.gov

Contract Number: DE-AI05-96OR22560

Contract Period: 10/97-10/2000

Contract Funding:

FY 1998: $20,000

FY 1999: $20,000

Objective: This research is being conducted as a part of the Cooperative Research and Development Agreement (CRADA) study at a research site near Sumter, SC, which is owned and operated by International Paper. The CRADA is a cooperative, proprietary research relationship between International Paper and Oak Ridge National Laboratory. The objective of this research is to determine movement of nutrients, particularly nitrates, in irrigation water passing below the rooting zone of the three tree crops (cottonwood, sycamore, and sweetgum).

Approach/Background: The three tree crops are being grown under an intensive fertigation regime, which includes two water levels, and two fertilization levels compared with non-irrigated control treatments of each of the three tree crops. The data from water collected from replicate tension lysimeters established within each of the tree crop plots will (1) document movement of water and nutrients, (2) identify the extent of nutrient migration and the potential for groundwater contamination, and (3) serve as documentation to help identify the amounts and timing of nutrient and water application to maximize growth while minimizing the potential for adverse environmental effects.

Status/Accomplishments: Water samples have been collected monthly during both the growing and dormant seasons from tension lysimeters established at 0.5 and 1.0 meter depths within each tree crop-fertilizer-water level combination in addition to shallow groundwater wells around the periphery of the site since 1997. Nitrates in subsurface waters were high and in some instances exceeded water quality standards during the initial year of tree crop establishment. These high levels were determined to be the result of residual nitrogen applied to agricultural crops that had been grown on the site prior to tree crop establishment. Data show that from 1998 to present the rates of nutrient application and nutrient uptake by the tree crops, particularly the faster growing cottonwood, limit nutrient movement below the rooting zone even at the higher rates of irrigation. Consequently, the data show that the potential for groundwater contamination from fertigation of the tree crops is remote.

Publications and Presentations:

1. Trettin, C.C., O'Ney, S., Todd, D.E., Tolbert, V.R. 1998. Water quality aspects and nutrient transport from short-rotation woody crop production. 1998 CRADA (Cooperative Research and Development Agreement) Annual report for International Paper.
2. Trettin, C.C., O'Ney, S., Todd, D.E., Tolbert, V.R. 1999. Water quality aspects and nutrient transport from short-rotation woody crop production. 1999 CRADA (Cooperative Research and Development Agreement) Annual report for International Paper.

Summary Date: September 1999

Soil Quality Changes with Production of Intensively Managed Tree Crop

Research Funded by: U. S. Department of Energy through the Oak Ridge National Laboratory

Project Manager: V. R. Tolbert, 865.574.7288, tolbertvr@ornl.gov

Performing Organization: Oar Ridge National Laboratory

Principal Investigator: Donald E. Todd, Jr.

865.574.7344, toddde@ornl.gov

Contract Number: DE-AI05-96OR22560

Contract Period: 10/97-10/2000

Contract Funding:

FY 1998: $40,000

FY 1999: $50,000

Objective: The objective of this research is to determine soil carbon accumulation with conversion of agricultural lands to biomass crop production.

Approach/Background: Soil samples have be taken from the plot-scale study sites in Alabama and the Cooperative Research and Development Agreement (CRADA) site in South Carolina to determine changes in soil carbon with conversion to biomass crops from agricultural crops. Replicate soil samples are being taken from the switchgrass, sweetgum both with and without a cover crop, and no-till corn for grain plots at the Alabama A&M University research site and from the tree crop (sycamore, sweetgum, and cottonwood) sites in South Carolina to document changes that occur over time. These data are being compared with those being collected from a related research site in western Tennessee and a site in Mississippi. The Mississippi site was harvested in the fall of 1997 and cotton reestablished on the plots in 1998 and 1999. The objective of the comparison at the Mississippi site is to identify changes that take place in belowground carbon sequestration as the stumps decompose in the soil and to document changes in carbon storage under the cottonwood following harvest.

Status/Accomplishments: During FY98 and FY99 samples were taken from the different treatments at the Alabama site and from the CRADA fertigation site at Sumter, South Carolina. Samples were taken to 60 cm depths and sectioned into 10 cm increments for carbon analysis. In addition to samples taken from the research plots, samples were collected from fallow reference sites and sites in agricultural crop production. These serve as baseline samples for comparison with those from the agricultural and biomass crops. The samples have been processed and sieved to remove root fragments >2mm in diameter prior to analysis. A summer student worked with the project in 1999 to help process and analyze the extensive samples from these collections. These samples are being used to document changes in carbon accumulation with conversion of agricultural lands to biomass crop production. Carbon increases under tree crops with a cover crop, switchgrass, and no-till corn have been identified in Alabama. Losses in carbon occurred with production of sweetgum without a cover crop. Sample analysis are in progress for the SC site.

Publications and presentations:

1. Tolbert, V. R., J. D. Joslin, F. C. Thornton, B. R. Bock, D. E. Pettry, W. Bandaranayake, D. Tyler, A. Houston, and S. Schoenholtz. 1999. Biomass crop production: benefits for soil quality and carbon sequestration. pp. 127-132, 4th Biomass Conference of the Americas, 1999.
2. Tolbert, V. R., J. D. Joslin, B. R. Bock, F. C. Thornton, D. E. Pettry, W. Bandaranayake, A. Houston, Don Tyler. 2000. Belowground carbon sequestration associated with conversion of agricultural lands to production of bioenergy crops. IEA Workshop on Integrating Production of Energy in Sustainable Forestry, 1999.

Summary Date: September 1999

Sustainability of High Intensity Forest Management with respect to Water Quality and Site Nutrient Reserves

Research Funded by: U. S. Department of Energy through the Oak Ridge National Laboratory

Project Manager: V. R. Tolbert, 865.574.7288, tolbertvr@ornl.gov

Performing Organization: USDA, Center for Forested Wetland Research, 2730 Savannah Hwy, Charleston, SC 29414, http://www.srs.fs.fed.us/charleston/index.html

Principal Investigator: Carl C. Trettin, 843.727.4271 ext. 103, trettinc@cofc.edu

Contract Number: DE-AI05-96OR22560

Contract Period: 10/96-10/2001

Contract Funding:

FY 1998: $120,000

FY 1999: $150,000

Objective: Specific Objective for this project include: 1) determining the effects of operational-scale cropping systems on soil chemical and physical properties, nutrients in surface and subsurface runoff, and sediment yield; 2) assessing the feasibility of designing water management systems to enhance crop production and control non-point source pollution; 3) determining the carbon balance following the conversion of agricultural land to woody crops; 4) assessing soil sustainability of short rotation cropping systems, and identifying indicators based on nutrient cycling and hydrologic models; and 5) developing an integrated assessment approach for short rotation woody crops through the application of landscape and processed-based hydrologic and biogeochemical models.

Approach/Background: Sustainable production of short rotation woody crops is dependent on development of highly productive growing stock and land management practices that conserve the biotic and abiotic tenants of soil and water resources. This project was developed in response to needs identified by the Department of Energy (DOE) and the American Forest and Paper Association. It is a cooperative effort between DOE, Oak Ridge National Laboratory, International Paper, USDA Forest Service, NC State University and the University of Nevada. A watershed-scale approach utilizing operational treatment designs is being used. The project involves research on both experimental catchments (i.e., >10 ac) and second order watersheds (i.e. >1000 ac) and is designed as a long-term experiment to address productivity and environmental questions regarding short rotation woody crops over the length of the rotation (10-12 years).

Status/Accomplishments: Soils were sampled in March '97, March '98 and March '99. Results indicate that cation levels are declining as a result of different fertilization regime under woody crops as compared to the prior agricultural practices.

Bulk density and infiltration measurements began in March 1999, and will be conducted annually. Bulk density in the planting line (1.49 gm/cm³) was less than the surface soils (1.62 gm/cm ³). A plow pan (1.82 gm/cm³) in the 15-30 cm zone is a result of the prior agriculture. Infiltration rates were found to be highly variable, probably as a result of site prep. Subsequent measurements are designed to detect changes in these important factors to soil tilth.

Water quality samples have been collected from tension lysimeters on a monthly basis, beginning in 1997. Soil water is acidic with an average pH range of 5.21-5.63. Nitrate levels, across all treatments, are low during the winter (Nov. - March), ranging from 2-7 ppm NO³-N, and then increase to 6-14 ppm NO³-N during the summer months (June-Sept). The temporal pattern suggests that nitrification (of both organic and fertilizer NH⁴ -N) is the primary mechanism, and that N availability is excessive for present stage of stand development (3 yrs). Waters draining from the site, as measured in weekly composite samples, exhibit slowly decreasing levels of NO ³-N.

Publications and Presentations:

1. Sustainability of high intensity forest management on water quality and site nutrient reserves. NCASI meeting, Atlanta, GA, March 1999.
2. Manuscripts in preparation: (a) Effects of Operational Short Rotation Woody Crop Systems on Surface Water Quality (b) Carbon and nutrient balance in young woody crop plantations: a comparison of sweet gum and sycamore.

Summary Date: September 1999

Use of Woody Biomass Crops Compared with Natural Forests by Breeding Birds in the Southeastern U.S.

Research Funded by: U.S. Department of Energy through the Oak Ridge National Laboratory

Project Manager: Virginia Tolbert, 865.574.7288, tolbertvr@ornl.gov

Performing Organization: Clark University, School of Geography, 950 Main St., Worchester, MA 01610-1477

Principal Investigator: Andrew Schiller, 508.793.7336, aschille@black.clarku.edu

Contract Number : 43000670

Contract Period: 12/97-12/00

Contract Funding:

FY98: $41,700

FY99: $ 6,700

Objective: To build upon previous studies conducted in other regions to determine if there are significant differences in breeding bird use of intensively managed tree crops compared with natural forests and agricultural crops.

Approach/Background: The approach taken was to identify breeding bird use of sites of different ages (~5 and 20 years old) , and acreages (~30 and 150 acres). Bird surveys were conducted during the 1996 and 1997 breeding seasons on sweetgum and sycamore plantations, naturally regenerating hardwood forests, and pine plantations on lands owned and managed by the wood products industry in the southeastern coastal plain. Replicates of all stands (both young and near harvest ages, and of small and large area) were included in the surveys. Bird community differences and bird community variation were evaluated by bird abundance, species richness, and proportions of birds in habitat guilds defined by vertical strata (ground, shrub, midstory, and canopy associated birds) comparisons.

Status/Accomplishments: The sweetgum and sycamore plantations were found to support remarkably similar bird communities to comparably aged hardwood forests. Bird communities on both managed and unmanaged forests change dramatically with age but follow similar trajectories from open, shrubby habitat to closed canopy structure; although bird abundance/stand age relationships differ, and shrub and midstory habitat guilds are supported in somewhat different proportions. Hardwood forests and pine stands have greatest bird abundance when young, and least abundance when near harvest age, whereas hardwood plantations have an opposite pattern. At near harvest age, hardwood plantations support a greater proportion of shrub-associated birds and a smaller proportion of midstory associated birds than either hardwood forests or pine plantations of similar age. Planted pine differs from both hardwood crops and hardwood forests; they have lower species richness and pine warblers dominate the bird community on near harvest age pine. Implications of land conversions to intensively managed woody crop production for bird communities will depend heavily on management of stand ages and acreages across entire landscapes, in combination with the types of landcovers converted.

Publications and presentations:

1. Schiller, A., Cresko, W.A., Lindberg, J.E., Tolbert, V.R. Bird Communities on Intensively Managed Forests From Planting to Harvest in the Southeastern United States. Submitted.
2. Schiller, A., Cresko, W.A., Lindberg, J.E., Tolbert, V.R. Breeding Bird Use of Hardwood Tree Crops: From Planting to Harvest Submitted.
3. Tolbert, V. R., J. Hanowski, W. Hoffman, A. Schiller, D. Christian, and J. Lindberg. 1997. Changes in bird community composition in response to growth changes in short-rotation woody crop plantings. p. 341-348. Proc., Third Biomass Conference of the Americas, Making a Business from Biomass in Energy, Environment, Chemicals, Fibers and Materials, Montreal, Quebec, August 24-29, 1997.

Summary Date: September 1999