2003 Annual Report 1.What major problem or issue is being resolved and how are you resolving it? The soil organic matter is very important because it acts as a glue to help stabilize soil structure and is a major reservoir of both plant nutrients and plant available water. Furthermore, soil organic matter is the largest terrestrial reservoir of organic carbon, and therefore the cycling of soil organic matter has a big influence on atmospheric levels of greenhouse gasses such as carbon dioxide and methane. New management systems that build organic matter in agricultural soils are critically needed to both enhance soil quality and to reduce the threat of global warming. We are studying the fundamental processes and factors that control the cycling of organic carbon and nitrogen in soils and how these processes and factors influence soil structure, carbon sequestration, and the ability of soils to retain plant nutrients and plant available water. 2.How serious is the problem? Why does it matter? Global warming and soil quality are issues that indirectly impact the lives of all Americans. Over the last 250 years about half of the organic matter has been lost from agricultural soils in the U.S. due to erosion and the effects of intensive tillage operations. Although agricultural production has increased dramatically over this same time period due to advancement in technology (increased use of fertilizer, hi-bred seeds, mechanization, and irrigation), we can not rely indefinitely on advances in technology to compensate for degradation of the soil resource base. Carbon sequestration in agricultural soils will not stop the increase in atmospheric levels of greenhouse gasses but it can significantly slow the increase. With prudent management over the next two decades, carbon sequestration in agricultural soils can reduce net increase in emissions of greenhouse gasses by 10 to 15%. 3.How does it relate to the National Program(s) and National Program Component(s) to which it has been assigned? National Program 202 - Soil Resource Management (70%) and National Program 204 - Global Change (30%) The project contributes to the National Program 202 - Soil Resource Management, by systematically addressing the physical, chemical, and biological factors and processes that influence soil nutrient cycling. The project will provide information necessary for the development of new management systems that enhance soil quality, and both water and nutrient use efficiency. The research will also advance the National Program 204 - Global Change, by addressing mechanisms of carbon storage in soils and evaluating the effects of different long-term agricultural management systems on levels of carbon sequestration in soils. A related project being pursued in support of this project includes a Trust Agreement with the Michael Fields Agricultural Institute (MFAI), 3625-12000-010-01T, "The effects of organic manures, grazing, and biodynamic growth regulators on cropping systems", which was funded to MFAI by USDA-CSREES-National Research Initiative. A Reimbursable Agreement with Michigan State University, 3625-12000-010-03R, "Mechanisms and Forces Controlling Pesticide Retention by Soil Clay Minerals," exists to improve understanding of pesticide behavior in soils. Another related project in support of this research is a Specific Cooperative Agreement with Iowa State University, 3625-12000-010-02S, "Use of micro-lysimetry and capillary electrophoresis to accurately determine phosphorus uptake potential in rhizosphere soil". 4.What were the most significant accomplishments this past year? A. Single most significant accomplishment during FY 2003: Reclamation of disturbed landscapes through reconstruction of diverse, species-rich native ecosystems can increase soil organic carbon (SOC) and enhance C (carbon) sequestration to mitigate increases in atmospheric CO2. Experiments were conducted by Dr. C. Cambardella, USDA-ARS National Soil Tilth Laboratory (NSTL) Ames, IA, and scientists from Iowa State University, Department of National Resources and Environmental Management Program (NREM), Iowa Department of Natural Resources (DNR) Geological Survey, and the U.S. Fish and Wildlife Service at Neal Smith National Wildlife Refuge (NSNWR) near Prairie City, IA, to quantify soil C pools and determine the effect of time since prairie reestablishment on soil C accumulation. Two short-term indicators of the longer-term potential to sequester stabilized SOC were identified. This information will help optimize our ability to detect changes in ecosystem parameters that occur with changes in land-use, climate, and management. B. Other Significant Accomplishment(s), if any: Agroforestry management protocols in tropical regions have decreased ecosystem biodiversity by replacing species-rich forests with monoculture tree plantations, resulting in unknown effects on soil fertility, soil carbon storage, and the global carbon cycle. Experiments were conducted by Drs. A. Russell, C. Cambardella, NSTL, and collaborating scientists from Iowa State University Department of NREM and USDA Forest Service La Selva Biological Station in Costa Rica to quantify the effects that three tree species had on soil organic matter quantity and quality, when grown under different rotation lengths in single-species stands and in mixed-species polycultures. We found that (1) increased biodiversity resulted in greater soil nutrient-supply capacity and C storage; (2) roots drove soil C accrual in these systems; (3) root organic matter quality, and not the amount of root inputs, best explained effects of species diversity on soil C sequestration. The results will help guide the development of agroforestry management decision-aids for selection of appropriate species mixtures to be used in tree plantations to enhance soil C storage and nutrient-use efficiency. Measurement of electrical current flow (electrical conductivity) through soil has been related to soil fertility and crop yield and to the amount of water, salt, clay, and organic matter in soil, but there is little understanding of why the relationships vary for each field. In laboratory studies at the NSTL, Drs. S. Logsdon and D. Laird measured electrical current in hydrated clay samples under a variety of temperature and humidity conditions. The electrical conductivity was shown to be high for clay samples, to vary with type of clay and salt present, and to increase with increasing water content, increasing temperature, and as the measurement time scale decreased. The study demonstrates that agronomists who use electrical conductivity maps as an aid in soil management need to be aware that their interpretations may be affected by field-to-field variability, and that scientists who study soil electrical conductivity need to focus more effort on understanding the effects of the time scale of measurement and the amount and type of clays and salts in soils on interpretations. Soil organic matter (SOM) plays key roles in many soil processes, yet the relationship between function and the chemical nature of SOM is largely unknown. Dr. D. Olk, NSTL, in collaboration with K. Schmidt-Rohr, Department of Chemistry, Iowa State University, applied newly developed software for nuclear magnetic resonance (NMR) spectroscopy to identify the types of organic molecules found in the SOM fractions and the degree of their spatial segregation. The study demonstrates that crop management regimes influence the accumulation of chemically reactive residues of woody plant tissues in the studied SOM fractions, and thorough spatial mixing of different types of organic molecules in the SOM fractions. Scientists will be able to use the results to better understand the effects of crop management on SOM properties and, in turn, on key soil processes affected by SOM, including cycling of soil nutrients. Scientists need to understand the mechanisms and processes by which new humic substances form in soils in order to develop management systems that improve soil quality and increase the sequestration of carbon in soils. Laboratory studies were conducted by J.M. Gonzalez, USDA-ARS Appalachian Farming Systems Research Center, Beaver, WV, and Dr. D. Laird, NSTL, to investigate a potential chemical pathway for the formation of humic materials from residues. We demonstrated that soil clay minerals are capable of catalyzing the formation of humic-like substances from simple sugars and amino acids. The study will help scientists understand how new humic substances form in soils. C. Significant Activities that Support Special Target Populations: None. D. Progress Report: Dr. D. Laird, NSTL, and C. Christy, Veris Technologies Inc., Salina, KS, field tested a newly developed real-time, on-the-go, near infrared spectrometer (NIRS) system for measuring soil properties in two agricultural fields near Ames, IA, and near Junction City, KS. Preliminary results indicate that the NIRS system can be used to simultaneously quantify the spatial distribution of organic carbon, nitrogen, cation exchange capacity, and lime requirement in the surface soils. 5.Describe the major accomplishments over the life of the project, including their predicted or actual impact. Dr. D. Laird, NSTL, in collaboration with Dr. D. Martens, USDA-ARS Southwest Watershed Research, Tucson, AZ, has discovered the existence of two distinct phases of clay-humic complexes in soils. One phase exists as discrete high density metal-humic complexes and appears to be a relatively old and stable reservoir of soil organic carbon. The other phase exists as diffuse films on surfaces of clay particles and appears to be a younger less stable form of organic carbon. The findings will help focus efforts to develop new management systems that encourage the formation and stabilization of organic matter in soils. Dr. S. Logsdon, NSTL, evaluated various methods for measuring changes in soil structure and demonstrated that existing methods are unable to quantify the effects of cropping system on the rate water moves through the soil, the density of the soil, the volume of large pores, or distance between large pores. The study indicates that scientists need to develop more sensitive techniques for measuring minor and short-term changes in soil structure, before soil structure can be used to assess whether management systems are improving or degrading soil quality. The work done by Dr. C. Cambardella, NSTL, and colleagues over the life of this project indicates that the ultimate impacts of reduced tillage, land-use change, and increased atmospheric CO2 on SOC are complex and interrelated and can lead to unexpected effects on long-term ecosystem C equilibrium. In growth-chamber experiments, Dr. W.J. Gale and Dr. C. Cambardella demonstrated that 75% of new soil C under no-till conditions came from roots. Most of the new C was occluded within macroaggregates in the form of root-derived particulate organic matter (POM) C and 66% of the surface residue C was lost as CO2. Further study showed no difference in SOC after 30 years of moldboard plowing in a corn silage cropping system when compared to conventional cash grain continuous corn. In related work, no consistently positive changes in SOC were identified for a chronosequence of reconstructed native prairies in central Iowa in place on the landscape for times varying from 1-10 years. However, accumulation of C in the heavy sub-fraction of POM, a biologically-active form of SOC, was greatest in native prairie remnant soils, intermediate in the oldest reconstructed prairie soils, and least in cultivated agricultural soil. In California grassland systems, we demonstrated that elevated CO2 increased the retention of older SOC but retarded the movement of newly fixed C from roots to stabilized SOC pools. In Central American tree plantations, we demonstrated that increased biodiversity led to higher amounts of SOC and that root organic matter quality controlled the SOC accrual in these systems. 6.What do you expect to accomplish, year by year, over the next 3 years? FY 2004: Determine the effects of organic-clay interactions on electrical properties of bound water. Quantify the effect of including meadow in crop rotations on the rate of change in soil organic carbon storage for Midwestern corn-soybean production systems. Complete initial phase of development of the decision aid tool, The Humus Budgetor, which will help farmers and land managers increase levels of soil organic matter. Develop an integrated chemical and physical procedure method for extracting organic matter fractions from soils that distinguish chemical binding and physical protection as stabilization mechanisms for soil organic matter. FY 2005 Determine whether near infrared spectroscopy can be used as a real-time on-the-go tool for quantifying soil organic carbon, inorganic carbon and total nitrogen. Determine the chemical nature of stabilized and labile soil organic matter and evaluate two different procedures for quantifying stabilized and labile soil organic matter. Evaluate the use of dielectric spectroscopy for characterizing undisturbed soil samples taken from management areas. FY 2006 Identify biochemical agents for soil aggregation and other physical properties through biochemical characterization of soil and soil aggregates that differ clearly in their physical properties. Develop a dielectric spectroscopy tool for assessing structure soil and soil water characteristics of field soils. Develop a NIRS tool for real-time on-the-go soil characterization. 7.What science and/or technologies have been transferred and to whom? When is the science and/or technology likely to become available to the end-user (industry, farmer, other scientists)? What are the constraints, if known, to the adoption and durability of the technology products? Under an established Cooperative Research and Development Agreement (CRADA) with a small agri-systems technology company, we have helped develop and field test a near infrared diffuse reflectance tool for real-time, on-the-go quantification of soil organic carbon, inorganic carbon and total nitrogen. Information on surface area analysis of clays was transferred to researchers in a large oil and gas exploration and development company. Information on methods for quantifying clay content in ink was transferred to a representatives of an ink manufacturing company. Information on the nature of clay-humic complexes was transferred to an Assistant professor at a Midwestern University and to a Professor at an Australian University. Information on environmental and industrial uses of polyacrylaminde was transferred to a representative of a company that manufactures a bonded fiber matrix materials, a material for treating disturbed soils (construction sites, etc.) to inhibit erosion. 8.List your most important publications in the popular press and presentations to organizations and articles written about your work. (NOTE: This does not replace your peer-reviewed publications listed below). "Extraction of Humic Acid Fractions Based on Binding to Soil Polyvalent Cations" poster presentation by D.C. Olk at the American Society of Agronomy-Soil Science Society of America National Meetings. Indianapolis, IN, Nov. 10-14, 2002. "Does Anaerobic Decomposition of Crop Residues Alter Soil Organic Matter Formation and Nutrient Cycling?" oral presentation by D.C. Olk at the 4th North Central Region Symposium on Natural Organic Matter in Soils and Water, Ames, IA, Mar. 21-22, 2003. "Soil Organic Matter Quality, Nitrogen Cycling and Yield Trends in Tropical Rice" seminar presented by D.C. Olk at the Department of Natural Resources and Environmental Sciences, University of Illinois, Sep. 2003. "Development of Near Infrared Reflectance Spectroscopy Soil Sensor Technology" oral presentation by D.A. Laird at the Department of Soil, Crop, & Atmospheric Sciences, Cornell University, Ithaca, NY, Feb. 4, 2003. "Layer Charge Analysis: Problems and Opportunities" oral presentation by D.A. Laird at a special Symposium on Methods of Soil Analysis-Mineralogical Methods during the American Society of Agronomy-Soil Science Society of America National Meetings, Indianapolis, IN, Nov. 10-14, 2002. "Carbon Dynamics of Soil Clay-Humic Complexes" poster presentation by D.A. Laird at the 4th North Central Region Symposium on Natural Organic Matter in Soils and Water, Ames, IA, Mar. 21-22, 2003. Review Publications KOMADEL, P., MADEJOVA, J., LAIRD, D.A., XIA, Y., STUCKI, J.W. REDUCTION OF FE(III) IN GRIFFITHITE. CLAY INTERNATIONAL CONFERENCE PROCEEDINGS. 2001. P. 20. WU, J., LAIRD, D.A. HYDROLYSIS OF CHLORPYRIFOS IN AQUEOUS AND COLLOIDAL SYSTEMS. ISRAEL JOURNAL OF CHEMISTRY. 2002. V. 42. P. 99-107. WU, J., LAIRD, D.A. ABIOTIC TRANSFORMATION OF CHLORPYRIFOS TO CHLORPYRIFOS OXON IN CHLORINATED WATER. ENVIRONMENTAL TOXICOLOGY AND CHEMISTRY. 2003. V. 22(2). P. 261-264. LOGSDON, S.D. DIELECTRICS-BEYOND WATER CONTENT. FIRST INTERNATIONAL SYMPOSIUM ON SOIL WATER MEASUREMENT USING CAPACITANCE IMPEDANCE AND TIME DOMAIN TRANSMISSION. 2002. P. 1.3.1-17. LOGSDON, S.D., LAIRD, D.A. PROPERTIES OF BOUND WATER ASSOCIATED WITH SMECTITES. SOIL SCIENCE SOCIETY OF AMERICA ANNUAL MEETING. 2002. CD-ROM. MADISON, WI. OLK, D.C. EXTRACTION OF HUMIC ACID FRACTIONS BASED ON BINDING TO SOIL POLYVALENT CATIONS. AGRONOMY ABSTRACTS. 2002. CD-ROM. MADISON, WI. LOGSDON, S.D., LAIRD, D.A. RANGES OF BOUND WATER PROPERTIES ASSOCIATED WITH A SMECTITE CLAY. ELECTROMAGNETIC WAVE INTERACTION WITH WATER AND MOIST SUBSTANCES PROCEEDING. 2003. P. 106-108. PILS, J.R., EVANGELOU, V.P., LAIRD, D.A. SMECTITE TACTOID FORMATION INDUCED BY CONFINED AND DOUBLE LAYER MONOVALENT CATIONS. AGRONOMY ABSTRACTS. 2002. CD-ROM. MADISON, WI. LAIRD, D.A. LAYER CHARGE ANALYSIS: PROBLEMS AND OPPORTUNITIES. AGRONOMY ABSTRACTS. 2002. CD-ROM. MADISON, WI. WASSMANN, R., BUENO, C.S., LANTIN, R.S., LU, W.F., CHAREONSILP, N., OLK, D.C. STRAW MANAGEMENT AFFECTING METHANE EMISSIONS FROM DIFFERENT RICE ECOSYSTEMS. WORLD CONGRESS OF SOIL SCIENCE. 2002. CD-ROM. BANGKOK, THAILAND. GONZALEZ, J.M., LAIRD, D.A. SMECTITE CATALYZED DEHYRATION OF GLUCOSE. CLAY MINERALS SOCIETY MEETING. 2003. Abstract p. 67. LOGSDON, S.D. SOIL WATER ENERGY CONCEPTS. ENCYCLOPEDIA OF WATER SCIENCE. 2003. P. 868-870. LOGSDON, S.D. WATER INFILTRATION AND SOIL. ENCYCLOPEDIA OF WATER SCIENCE. 2003. P. 930-933. LOGSDON, S.D. ANTECEDENT SOIL WATER. ENCYCLOPEDIA OF WATER SCIENCE. 2003. P. 858-860.