Soil biochemistry and microbiology are concerned with the role of soil microorganisms, minerals and organic matter in nutrient and toxicant transformations in soils—particularly in relation to soil fertility and environmental quality—and the ecology of indigenous and introduced microorganisms in soil.
Current research programs are evaluating the factors and mechanisms controlling the rate, nature, and extent of microbial decomposition of organic wastes and chemicals, crop residues and organic toxicants in soil and focus on the microbial and biochemical aspects of soil quality from the viewpoints of sustainable agriculture and environmental protection. These programs offer a diversity of project orientations, ranging from field and laboratory studies on the biochemical factors involved in movement of pesticides to groundwater and bioremediation of soils contaminated by leaking underground storage tanks, to characterization and use of microbial/biochemical indices of soil health and molecular indicators of microbial gene expression in soils.
Studies of the persistence, distribution, fate and toxicity of pesticide residues in soils in the rooting zone, the vadose zone and groundwater are related to risk assessment, regulatory standard-setting, pest control practices, and remediation of contaminated sites.
Students interested in specializing in soil biochemistry and microbiology should have a solid background in general chemistry (including organic, physical, and analytical chemistry) and biochemistry or microbiology. Our graduate students normally supplement their soils major with a minor or joint major in fields such as bacteriology, biochemistry, plant pathology, water chemistry, hydrogeology, water resources, or environmental toxicology.
Faculty members in this area (J.M. Harkin, R.F. Harris, and W.J. Hickey) all have joint appointments in other programs/departments (Environmental Toxicology Center, Bacteriology Department).
Soil chemistry and soil mineralogy are pivotal to a clear understanding of soil behavior. The suitability of soils for various uses is profoundly affected by their chemical and mineral composition. The effectiveness of many soil functions, such as their ability to provide nutrients to plants, the reactions of fertilizers and pesticides with soils, and the capacity of soils to assimilate wastes, depends largely upon the chemical and mineralogical properties of soils. The use of soils to support roads and buildings and the susceptibility of soils to erosion, as well as other soil physical properties, are also influenced by the chemical and mineralogical composition.
Soil chemistry is closely related to soil mineralogy and soil fertility. Many students who specialize in soil chemistry also study one of these related subjects. Background courses in chemistry (analytical and physical), geology (mineralogy, geochemistry, and x-ray diffraction), or plant sciences (botany, horticulture, and agronomy) are often taken by students specializing in soil chemistry. Some students combine their studies of soil chemistry and mineralogy with other disciplines, such as geology, hydrogeology, and environmental sciences.
Training of graduate students in these disciplines includes research and coursework. An M.S. degree offers students an opportunity to gain experience in research. Completing a Ph.D. degree provides additional training in investigative and communication skills for independent research.
Much current research in these disciplines focuses on the behavior, occurrence, and movement of elements, compounds, and minerals in soils. Other important areas of research concern the development and refinement of analytical procedures to measure amounts and availability of soil components and study their interactions with plants. Theoretical studies of the atomic structure of soil compounds and NMR and other physicochemical studies provide detailed knowledge of soil reactions.
Faculty members in this area are P. Barak, W. F. Bleam and P.A. Helmke.
Soil fertility and plant nutrition research encompasses the study of soil related to nutrient availability in plants, nutrient requirements of different crops, fertilizer use, soil testing and plant analyses, and crop utilization of nutrients in wastes applied to the soil. Consideration of the environmental and economic consequences of soil fertility practices are essential components of this research.
Soil tests are developed for plant nutrients likely to be deficient in Wisconsin soils. These tests are calibrated for the major field and vegetable crops grown in the state, providing the basis for lime and fertilizer recommendations. Fertilizer rates and application methods and timing are studied to optimize production economics. Criteria for interpreting the results of plant analyses are developed through field and greenhouse studies that relate plant composition to crop yields. Work in soil fertility and plant nutrition often involves cooperation with other CALS departments, and usually overlaps other areas of soil science, e.g. soil biochemistry/microbiology and soil chemistry/mineralogy.
Research in soil fertility and plant nutrition includes the study of: fertilization and liming of forage, corn, soybeans, potatoes and other important Wisconsin crops; land application of manure, papermill and sewage sludge, whey, fly ash, and other waste products; short- and long-term availability of various forms of nitrogen and phosphorus, the occurrence of sulfur deficiency in relation to atmospheric contributions and soil characteristics; and soil testing and plant analyses.
Students seeking advanced degrees in soil fertility and plant nutrition should have or develop a strong background in agronomy or horticulture, chemistry, botany, and mathematics. Other appropriate courses can be selected in the bacteriology, entomology, plant pathology, weed control, statistics, and computer science areas.
Most faculty members in soil fertility and plant nutrition have Extension appointments in addition to their research and teaching duties. Some have had professional experience in developing countries. Faculty members include L.G. Bundy, L.R. Cooperband, K.A. Kelling, and W.R. Kussow. P. Barak is involved primarily in soil chemistry and mineralogy, but has additional interest in soil fertility research.
Forests cover 43 percent of Wisconsin's land area. Wisconsin is the top papermaking state in the nation and is also a leader in Christmas tree production. State and private nurseries produce about 25 million tree seedlings per year—the most valuable land use in production agriculture! Not only are Wisconsin's woodlands used for timber and fiber production, but also for recreation, water conservation, and recycling of municipal and industrial byproducts. Understanding soils is essential to the prudent management of Wisconsin's woodlands and commercial, state and national forests for these purposes.
Several major problems face forest soil scientists in Wisconsin: (1) How to identify prime soils for intensive silviculture to meet the increased national and international demand for timber, pulpwood and forest products? (2) How to match the most productive/ healthiest tree species to growth sites? (3) What effects do intensified forest management practices, such as mechanical and chemical site preparation, use of fast-growing hybrid species, species conversion, whole-tree harvesting, and shortened rotations, have on future productivity of forest soils in the state? (4) Can municipal and industrial byproducts be recycled safely and effectively on forest lands to improve site quality and avoid ground-water pollution? (5) How can soil survey and interpretation information be improved to benefit the forest manager?
Forest soil science is related closely to other divisions of soil science. Knowledge of soil physics, and soil and water management/conservation is vital to managing forested watersheds. Similarly, training in soil chemistry, soil microbiology, and soil fertility is important for understanding nutrient relations of forest soils. A background in soil genesis and classification is desirable for land-use planning in forested areas.
The forest soils graduate degree program at UW-Madison is directed by J.G. Bockheim and J.G. Iyer; both have joint appointments in the UW-Madison Department of Forestry and work closely with the state's natural resources agency and forestry-related industries.
Pedological research is concerned with the genesis and classification (taxonomy) of soils and their delineation on soil maps. Pedological studies help clarify how soils form and function, how they are arranged in the landscape, and how to predict and manage the ways in which soils interact with land uses.
Pedologists think of soil as a mosaic of individual soil bodies that collectively blanket most of the earth's land surface. The composition and arrangement of horizons (layers) in each soil depend on the geologic materials from which they were formed, the environment in which formation took place, and the duration of the process. Boundaries between individual soils are usually gradual, but can be sharp and clear where one or more soil-forming factors may change abruptly. Soil morphologists perform supporting detailed examinations of small bodies of soil, just as electron microscopists might examine individual cell components, rather than a whole organ, plant or animal.
Soils are classified on the basis of morphological characteristics such as color, texture, and depth, and their mineralogical, chemical, and physical properties. These are all related to soil genetic processes. For practical purposes, soils are also grouped according to their suitability or limitations for particular uses or applications. Soil maps are an abstract picture of soil landscapes, as interpreted by soil surveyors who, on the basis of borings or excavations at carefully selected sites and study of the landscape, identify and sketch soil boundaries on base maps, nowadays with assistance of sophisticated electronic devices and instrumentation, such as ground-penetrating radar, digitized satellite imagery, computerized graphic overlays, and geographic information systems. These are all active areas of current research.
Soil maps and interpretive data are being incorporated more and more into land-use planning. They are also used for zoning, other regulatory purposes, and in tax assessment of rural lands. There is an increasing demand for sophisticated, detailed soils data, and for skilled, reliable predictions of soil behavior under specified conditions. Innovative computer techniques to store, manipulate, and retrieve soil data are now helping pedologists make maximum use of new and existing information.
Much work in both basic and applied pedology is done cooperatively with other soil scientists, specialists in other University departments/programs, and professionals in state and federal agencies. Soil genesis investigations usually entail some studies of soil chemistry, mineralogy and physics; land-use studies may require detailed economic analyses. Major responsibility for detailed county soil surveys in Wisconsin rests with the USDA Soil Conservation Service and Forest Service.
Faculty members primarily involved with soil classification and land use include J.G. Bockheim, F.W. Madison, K. McSweeney, E.J. Tyler and S.J. Ventura.
Study of the physics of heat, water, and chemical movement in soils and the environment began at the University of Wisconsin in 1890, with the appointment of Franklin H. King as Agricultural Physicist. Activities of the present-day soil and environmental physics group combine King's vision of sustained food and fiber productivity with the current imperative to maintain environmental quality.
The physics group within Soil Science now pursues such diverse research problems as how subtle changes in soil texture short-circuit the flow of water and chemicals toward ground-water, and interpretation of satellite images to predict crop leaf temperatures. Investigations range from theoretical considerations of radiation balances within crop canopies to more immediate questions of how tillage practices affect soil warming and plant growth in the spring. Advancing frontiers of scientific knowledge through the solution of problems that face society today is a major theme.
Research in soil and environmental physics is often conducted cooperatively with researchers in several other departments, including physics, meteorology, geology, plant pathology, entomology, agricultural engineering, forestry, horticulture and agronomy. Graduate students in the soil and environmental physics program may choose to emphasize the soil physics, micrometeorological, hydrological or hydrogeological aspects of the environment. These programs usually have direct application to agronomic and environmental issues such as crop production, soil microbiology, and groundwater quality; accordingly, some students may pursue additional biological or geochemical training.
Computer simulation modeling is an important tool in soil and environmental physics used extensively by the group to develop and test hypotheses about soil and atmospheric systems. For example, modeling helps to elucidate how the shape of a crop canopy influences the duration of leaf wetness, a matter of great concern to plant pathologists. All members of the group participate in extensive field experimentation programs. For example, field experiments were used to verify a strategy for improved control of Colorado potato beetles based on knowledge of the soil thermal regime: mulching entices beetles to concentrate in small areas for over-wintering, where populations can be controlled without chemicals by removing the mulch and snow cover over these areas when the soil temperature falls briefly to -8°C with passage of an Arctic front. In another example, measurements of soil respiration and vegetation photosynthesis are being combined into a soil-plant-atmosphere model, designed to estimate the carbon budget of a native prairie grassland. Carbon balances of natural plant communities are needed to understand their influence on global carbon budgets.
Pursuit of a degree within the soil and environmental physics program allows emphasis in a wide range of areas including meteorology, geology, plant physiology, soil and water management/conservation and engineering, hydrology, computer science, forestry, integrated pest management, or physics. Minimum course preparation outside the Department of Soil Science usually includes mathematics (through differential equations) and intermediate courses in either physics or meteorology. Other applicable courses include plant physiology (botany), transport phenomena, and computer science.
Faculty members in the environmental physics group include W.L. Bland, K-J.S. Kung, B. Lowery, and J.M. Norman.
Wisconsin has a long tradition of leadership in soil and water conservation. Over 60 years ago, Wisconsin was a pioneer in developing conservation practices as part of a watershed protection plan that eventually served as a model for national efforts in soil and water conservation. In recognition of this leadership, the Coon Creek Watershed in Coon Valley, Wisconsin was designated "Watershed No. 1" and is now a national historic site.
The major goal of this early work was to control excessive erosion from cropland and maintain long-term agricultural production. Today's focus on soil and water management/ conservation has broadened to include surface and groundwater quality, and the long-term profitability of wise stewardship of the land.
Wisconsin's leadership in the water quality area culminated in the nation's first state-funded watershed program aimed at minimizing nonpoint pollution. Ongoing cooperative research programs with state agencies, municipalities, and industry have focused on areas such as proper handling and disposal of wastes, development of management practices for controlling pollution of waterways by sediment and nutrients in farmland runoff/drainage, and management of agricultural chemicals for production efficiency with preservation of environmental quality.
Maintaining agricultural production while protecting farm profitability and natural resources requires well trained personnel with interest and experience in interdisciplinary efforts. The department has a tradition of cooperation with other expertise within the University and outside agencies. Waste management and soil and water conservation are areas that traverse several disciplines and the mandates of state and federal regulatory agencies. Research continues into the use of soils as a medium for safe, economic disposal of papermill and municipal sludge, power plant and incinerator fly ash and bottom ash, onsite domestic/industrial wastewater, and soils from contaminated sites.
Conservation tillage remains a main research topic because of its potential for soil erosion control with improved production efficiency. Concern continues over its effect on surface and groundwater quality. Production aspects, such as lower soil temperature and nutrient availability, require further investigation and cooperation with scientists in other fields. Current projects are examining the potential for increased contamination of the surface and ground-water by pesticide residues using field and laboratory studies in conjunction with computer modeling.
Several programs are now examining practices to minimize groundwater contamination through better management. Mathematical modeling is evolving to identify potential problems from agricultural and industrial contaminants through long-term field studies, coupled with laboratory and monitoring efforts. To address groundwater issues, soil science expertise is supplemented with inputs from disciplines such as agricultural engineering, agronomy, entomology, plant pathology, agricultural economics, water chemistry, and sociology.
Faculty members in the soil and water management/conservation area are B. Lowery, F.W. Madison, and E.J. Tyler.