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Advances in Agronomy continues to be recognized as a leading reference and a first-rate source of the latest research in agronomy. Major reviews deal with the current topics of interest to agronomists, as well as crop and soil scientists. As always, the subjects covered are varied and exemplary of the myriad subject matter dealt with by this long-running serial. Editor Donald Sparks, former president of the Soil Science Society of America and current president of the International Union of Soil Science, has just been appointed the S. Hallock du Pont Chair of Plant and Soil Sciences at The University of Delaware. * Maintains the highest impact factor among serial publications in Agriculture* Presents timely reviews on important agronomy issues * Enjoys a long-standing reputation for excellence in the field
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vi CONTENTS VI. Applications of 15N Pool Dilution . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . A. Factors That Regulate Gross N Fluxes . . . . . . . . . . . . . . . . . . . . . . . . B. Quantifying the Actual Magnitude of N Cycling . . . . . . . . . . . . . . . . . C. C and N Mineralisation . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . D. Competition for Substrate Availability . . . . . . . . . . . . . . . . . . . . . . . . E. Soil Disturbance . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . F. Activity of Ammonia-oxidisers in Soil . . . . . . . . . . . . . . . . . . . . . . . . G. N Saturation Index . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . VII. Future Research . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Acknowledgments . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . References . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 96 96 99 102 104 105 107 108 109 110 110 DISTRIBUTION AND MANAGEMENT OF SELENIFEROUS SOILS K. S. Dhillon and S. K. Dhillon I. II. III. IV. V. VI. VII. VIII. IX. X. XI. XII. Introduction . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Historical Aspects . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Properties and Uses of Se . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Rocks and Minerals Containing Se . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Formation of Seleniferous Soils . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Se Additions to the Environment . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . A. Natural Sources . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . B. Anthropogenic Activities . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Geographical Distribution of Se Toxic Soils . . . . . . . . . . . . . . . . . . . . . . . Se in the Seleniferous Environments . . . . . . . . . . . . . . . . . . . . . . . . . . . . . A. Seleniferous Soils . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . B. Se in Water . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . C. Se in Plants . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . D. Se in the Atmosphere . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Effects of Se Toxicity on the Components of the Ecosystem . . . . . . . . . . . A. Plants . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . B. Animals . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . C. Selenium Toxicity in Humans . . . . . . . . . . . . . . . . . . . . . .