Measurements & Models for Macropore Infiltration in Soil

 

This seminar by Dr. John Norman shows how to use a single-ring, dual-head, ponded infiltration technique with the analysis of Reynolds and Elrick to get key parameters for use in a macropore infiltration model. These same measurements can also be used to obtain values of the saturated hydraulic conductivity which is useful for traditional infiltration models such as the Green and Ampt formulation. Macropore models that include characterization of the geometry of the macropores tend to be complicated and require more parameters than can be determined from a reasonable set of independent measurements. The M&M model is a relatively simple macropore model that requires only nine parameters. Three or four of these can be determined from a standard description of soil structure. One comes from the Coefficient of Linear Extensibility and four or five are obtained from ponded-infiltration and hydraulic properties measurements. This seminar will focus on the ponded infiltration measurements. The parameters from hydraulic properties will be the subject of another seminar.

Professor Norman received a B.S. in Physics and M.S. in Soil Physics at the University of Minnesota, and a Ph.D. in Soil Physics at the University of Wisconsin.

After a fellowship at the University of Aberdeen in Aberdeen, Scotland, in the Department of Forestry, he spent six years at The Pennsylvania State University in the Department of Meteorology, 10 years at the University of Nebraska in the Department of Agronomy, and has been a member of the faculties of the Department of Soil Science and the Department of Atmospheric and Oceanic Science at the University of Wisconsin since 1988. The central theme of Professor Norman's career has been studying the interaction between plants and their environment; in this context environment includes abiotic (soil and atmosphere) and biotic (plants, diseases, insects, etc.) factors. Efforts have involved measurements, instrument development and integrative modeling. Because of this broad emphasis, a distinctive feature of his career has been collaborative activity. Much of his research over the past 20 years has been captured in the detailed plant-environment model named Cupid, with applications to agriculture, ecology, forestry and meteorology. These applications have included plant productivity and water-use efficiency, integrated pest management, irrigation water use, grassland and forest carbon fluxes from vegetation and soil, measurements of vegetation canopy architecture and remote sensing. More recent activities emphasize the use of insights gained from years of fundamental research to provide guidance to decision makers. Collaborations with colleagues in space sciences, forestry, meteorology and agriculture have led to the development and distribution of satellite-based products to provide guidance to cranberry growers on the likelihood of frost and potato farmers on the possibility of conditions favorable to the development of potato blight. Current efforts focus on assisting farmers with management decisions that maintain yields and minimize environmental degradation through precision farming techniques.