Phillip Barak - Associate Professor

Soil chemistry and plant nutrition

Contact Information

Phone: 608-263-5450
Fax: 608-265-2595
Email: pwbarak@wisc.edu
Office: 167A Soil Science

Education

• B.S. Agriculture, 1976, Faculty of Agriculture (Rehovot), Hebrew University of Jerusalem
• M.S. Soil Science, 1982, Faculty of Agriculture (Rehovot), Hebrew University of Jerusalem
• Ph.D. Soil Science, 1988, Faculty of Agriculture (Rehovot), Hebrew University of Jerusalem

Teaching and Research

I am responsible for teaching an advanced undergraduate/graduate course, Mineral Nutrition of Plants, jointly listed with Agronomy, Botany, and Horticulture, as well as co-teaching an undergraduate course, Soil Nutrient Management.

The central focus of my research program is the soil chemistry of plant nutrients. A major direction is the integration of the equilibrium state and kinetics of relevant soil reactions, diffusion and transport of plant nutrients to roots, and a quantitative description of nutrient uptake and interaction at the root/soil interface reflecting rhizosphere chemistry. Such integration may be achieved by balancing experimental studies in soil and nutrient culture with mechanistic modeling of the root-soil environment.

Experimental aspects of the program will seek to widen traditional concepts of soil fertility to include rhizosphere fertility, and its possible management, and to emphasize the importance of nutrient interactions.

Modern mechanistic soil-nutrient models must simultaneously encompass all major nutrients in order to force mass balance, charge balance, and conform to realistic nutrient ratios in plant tissue. In addition, the difficult problem of nutrient uptake interactions may be describable in mathematical and thermodynamic terms by application of Onsager's reciprocal relations and mathematical optimization of parameters based on a broad data base. Experimentation will be needed to demonstrate the general applicability of the reciprocal relations approach to nutrient uptake in plants. Such an approach may address a number of questions integrating soil science and plant sciences, including the bioavailability of phosphorus and iron, particularly among those plant species which either exude chelating compounds into the root environment or acidify the rhizosphere under nutrient-deficient conditions. Additionally, a quantitative, mechanistic approach to the soil chemistry and rhizosphere chemistry of plant nutrients is particularly applicable to agricultural systems that are low input either by choice, as in low-input sustainable agricultural systems, or by necessity, as in undercapitalized agricultural regions of the world. Parts of the model described are appropriate for modeling the effects of agricultural practices as disparate as liming, on one hand, and commercial hydroponics, on the other.

Publications

• Barak, P., and E.A. Nater. 2005. The Virtual Museum of Molecules and Minerals: Molecular visualization in a virtual hands-on museum. J. Nat. Res. Life Educ. 34:67-71.


• Avila-Segura, M., J.W. Lyne, J.M. Meyer, and P. Barak. 2004. Rapid spectrophotometric analysis of soil phosphorus with a microplate reader. Comm. Soil Sci. Pl. Anal. 35:547-557.


• Grunwald, S., and P. Barak. 2003. 3D geographic reconstruction and visualization techniques applied to land resource management. Trans GIS 7(2):231-241.


• Grunwald, S., and P. Barak. 2002. The use of VRML for virtual soil landscape modeling. Syst. Anal. Model. Simulation 41:755-776.


• Mafongoya, P.L., P. Barak, and J.D. Reed. 2000. Carbon, nitrogen and phosphorus mineralization of tree leaves and manure. Biol. Fert. Soils 30:298-305.


• Starr, G., P. Barak, B. Lowery, and M. Avila-Segura. 2000. Soil particle size concentrations and size analysis using a dielectric method. Soil Sci. Soc. Am. J. 64:858-866.


• Grunwald, S., P. Barak, K. McSweeney, and B. Lowery. 2000. Soil landscape models at different scales portrayed in Virtual Reality Modeling Language (VRML). Soil Sci. 165:598-615.


• Sherman, L.A., and P. Barak. 2000. The solubility and dissolution of dolomite [CaMg(CO3)2] in Mg-HCO3/CO3 solutions at 25 o C and 1 atm CO2 . Soil Sci. Soc. Am. J. 64:000-000. (In press).


• Barak, P., B.O. Jobe, A.R. Krueger, L.A. Peterson, and D.A. Laird. 1998. Effects of long-term soil acidification due to agricultural inputs in Wisconsin. Plant Soil 197:61- 69.


• Barak, P., and I. Goldman. 1997. Antagonistic relationship between selenate and sulfate uptake in onion ( Allium cepa ): Implications for the production of organo-sulfur and organoselenium compounds in plants. J. Agric. Food Chem. 45:1290-1294.


• Hernández-Apaolaza, L., P. Barak, and J.J. Lucena. 1997. Chromatographic deter- mination of commercial Fe(III)-chelates of EDTA, EDDHA and EDDHMA. J. Chromatogr. A. 789(1&2):453-460.


• Barak, P., C.A. Seybold, and K. McSweeney. 1996. Self-similitude and fractal dimension of sand grains by computer-assisted image analysis. Soil Sci. Soc. Am. J. 60:72-76.


• Barak, P., J. Smith, A.R. Krueger, and L.A. Peterson. 1996. Measurement of short-term nutrient uptake rates in cranberry by aeroponics. Plant Cell Environ. 19:237-242.


• Barak, P., L.A. Sherman, and B.O. Jobe. 1996. Comments on "Design and construction of a personal computer-based automatic titrator." Soil Sci. Soc. Am. J. 60:630.


• Barak, P. 1996. Smoothing and differentiation by adpative-degree polynomial filter (modified Savitzky-Golay method). Anal. Chem. 67:2758-2762.


• Barak, P., and P.A. Helmke. 1993. The chemistry of zinc. p. 1-13. In A. Robson (ed.) Zinc in soils and plants. Kluewer Academic Press, New York.


• Welhouse, G., P. Barak, and W.F. Bleam. 1993. Dimerization constants of atrazine and CF 3 -labeled atrazine. J. Phys. Chem. 97:11583-11589.


• Bouabid, R., E.A. Nater, and P. Barak. 1992. Measurement of pore size distribution in a lamellar Bt horizon by epifluorescence microscopy and image analysis. Geoderma 53:309-328.


• Hadas, A., M. Sofer, J.A.E. Molina, P. Barak, and C.E. Clapp. 1992. Assimilation of nitrogen by soil microbial population: NH 4 vs. organic N. Soil Biol Biochem. 24:137-143.


• Barak, P., and Y. Chen. 1992. Equivalent radii of humic macromolecules from acid-base titration. Soil Sci. 152:184-195.


• Laird, D.A., P. Barak, E.A. Nater, and R.H. Dowdy. 1991. Chemistry of smectitic and illitic phases in interlayered soil smectite. Soil Sci. Soc. Am. J. 55:1499.1504.


• Baruch, E., D. Lichtenberg, P. Barak, and S. Nir. 1991. Calcium binding to bile salts. Chem. Phys. Lipids 57:17-27.


• Barak, P., Y. Coquet, T. Halbach, and J.A.E. Molina. 1991. Evaluation of the biodegradability of polyhydroxybutyrate (co-hydroxyvalerate) and starch-incorporated polyethylene plastic films in soils. J. Environ. Qual. 20:173-179.


• Barak, P., J.A.E. Molina, A. Hadas and C.E. Clapp. 1990. Optimization of an ecological model with the Marquardt algorithm. Ecol. Modelling 51:251-263.


• Barak, P., J.A.E. Molina, A. Hadas and C.E. Clapp. 1990. Mineralization of amino acids and evidence for direct assimilation of organic nitrogen. Soil Sci. Soc. Am. J. 54:769-774.


• Barak, P. 1990. SPECIES: A spreadsheet for modeling speciation of soil solution. J. Agron. Educ. 19:44-46.


• Barak, P. 1989. Double layer theory prediction of Al-Ca exchange on clay and soil. J. Colloid Interface Sci. 133:479-490.


• Barak, P., and Y. Chen. 1987. Determination of FeEDDHA in soils and fertilizers by anion exchange chromatography. Soil Sci. Soc. Am. J. 51:863-896.


• Barak, P., and Y. Chen. 1987. Three-minute analysis of chloride, nitrate, and sulfate by single column chromatography. Soil Sci. Soc. Am. J. 51:257-258.


• Barak, P., and Y. Chen. 1984. The effect of potassium on iron chlorosis in calcareous soils. J. Plant Nutrition 7:125-133.


• Chen, Y., and P. Barak. 1982. Iron nutrition of plants in calcareous soils. Adv. Agron. 35:217-240.

Awards and Honors

EduCause Medal, 1999
Wisconsin Teaching Scholar, 2006-07