Advances in Soil Science Advances in Soil Science B.A. Stewart, Editor Editorial Board R. Lal C.W. Rose U. Schwertmann B.A. Stewart P.B. Tinker R.J. Wagenet B.Yaron Advances in Soil Science Volume 20 Edited by B.A. Stewart With Contributions by M. Becker, B.T. Christensen, D.l. Horne, C.S. Khind, J.K. Ladha, RP. Pareek, T.B. Parkin, l.A. Robinson, Bijay-Singh, Yadvinder-Singh, M.G. Wallis With 67 Illustrations Springer-Verlag New York Berlin Heidelberg London Paris Tokyo Hong Kong Barcelona Budapest B.A. Stewart USDA Conservation & Production Research Laboratory Bushland, TX79012, USA ISSN:0176-9340 Printedonacid-freepaper. ©1992Springer-VerlagNewYork, Inc. Softcoverreprintofthehardcover Istedition1992 Copyright is not claimed for works byemployeesofthe United Statesgovernment. All rights reserved. This work may not be translated orcopied in wholeorin part without thewritten permissionofthe publisher(Springer-VerlagNewYork, Inc., 175FifthAvenue, New York, NY 10010, USA), except for brief excerpts in connection with reviews or scholarly analysis. Use in connection with any form of information storage and retrieval, electronic adaptation, computer software, or by similar or dissimilar methodology now known or hereafterdeveloped is forbidden. The use of general descriptive names, trade names, trademarks, etc., in this publication, even ifthe former are not especiallyidentified, is not to be taken asasignthatsuch names, as understood by the Trade Marks and Merchandise Marks Act, may accordingly be used freely by anyone. Production managed byDimitry L. Loseff; Manufacturingsupervised byJacqui Ashri. Typeset byBest-setTypesetter Ltd., Hong Kong. 9 8 7 6 5 432 1 ISBN-13:978-1-4612-7724-8 e-1SBN-13:978-1-4612-2930-8 001: 10.1007/978-1-4612-2930-8 Preface The key to sustaining the soil resource base is to maintain, or enhance, soil quality. Soil quality cannot be seen or measured directly from the soil alone but is inferred from soil characteristics and soil behavior under defined conditions. In essence, the quality of soils is analogous to the health of humans, and just as there is no single characteristic that can be measured to quantify a person's health, there is no single measurement that can quantify soil quality. However, there are certain characteristics, particularly when considered together, that are good indicators. Soil quality, just as human health, can be maintained or enhanced by good management practices; and seriously degraded-sometimes irrevers ibly-with poor practices. Soil quality is also important because it has direct and indirect effects on air quality and water quality. While the enhancement of soil quality does not always assure parallel improvements in the quality of air and, particularly, water resources, this is often the case. However, soil deg radation is invariably accompanied by degraded qualities of both air and water resources. The consensus among many scientists is that the greatest challenge is not increasing production, but preventing serious deterioration ofthe soil and water resource base so that the production level can be sustained. Soil degradation is a complex phenomenon produced by a strong inter action between socioeconomic and biophysical factors, which today include the effects of increasing population, a fragile economy, and dismal farm policies, as well as the fragility of soil itself and the harsh ness of climate. Soil degradation can be subtle and slow until a certain threshold is reached, and then it deteriorates rapidly. Advances in Soil Science provides a forum for leading scientists to analyze and summarize the available information on a topic, assessing its importance and identifying additional research needs. Most importantly, vi Preface contributors are asked to develop principles that have practical applica tions to both developing and developed agriculture. Advances in Soil Science was formulated to be international in scope and cover all subjects relating to soil science. This volume certainly fulfills those goals in that authors are from Denmark, the Philippines, New Zealand, India, United States, and Australia; and the topics cover organic matter, green manures, legumes, soil water repellency, and statistics. The reception ofAdvances in Soil Science by both authors and readers has been very gratifying. I want to thank the the authors for their excellent contributions, the Editorial Board for their help in selecting such competent contributors, and the Springer-Verlag staff for their kind and efficient assistance. Last, and most important, I want to thank the readers for their acceptance and use ofAdvances in Soil Science. B.A. Stewart Contents Preface. .................................................. v Contributors. .............................................. ix Physical Fractionation ofSoiland Organic Matterin Primary ParticleSizeand Density Separates. ........................... 1 Bent T. Christensen I. Introduction .................................... 2 II. Soil Fractionation Methodology 4 III. Soil Organic Matter (SOM) in Density Separates. .......... 26 IV. Chemical CharacteristicsofSOM in Size Separates. ........ 38 V. DynamicsofSOM in Size Separates. ..................... 50 VI. The Use ofSize Separation in Applied Research. .......... 71 VII. Feasibility ofPhysical Soil Fractionation in SOM Studies. ... 74 References 76 Soil Water Repellency. ...................................... 91 M.G. Wallis and D.J. Horne I. Introduction ........................................... 92 II. The EffectsofRepellency 93 III. Definition and MeasurementofRepellency 98 IV. Development ofRepellency. ............................. 110 V. Amelioration of Repellency. ............................. 129 VI. Conclusions and Future Research Priorities ................ 137 References .. .......................................... 138 Stem-Nodulating Legume-Rhizobium Symbiosisand Its Agronomic Usein Lowland Rice. ....................................... 147 J.K. Ladha, R.P. Pareek, and M. Becker I. Introduction 148 II. Diversity ofStem-Nodulating Legumes 149 VIIJ Contents III. Working Definition ofStem Nodule. .................... 153 IV. Classification ofStem-Nodulating Rhizobia. .............. 153 V. Infection Process, Nodule Formation, and Fine Structure of Stem Nodules 158 VI. Biological Nitrogen Fixation and N Accumulation by Stem- Nodulating Legumes .. ................................ 160 VII. Factors Affecting Symbiosis ............................ 164 VIII. Agronomic Use ofthe Stem-Nodulating Legumes. ........ 175 IX. Conclusion and Agenda for Future Research 183 References. .......................................... 185 AnalysisofLognormal Data .................................. 193 T.B. Parkin andJ.A. Robinson I. Introduction........................................... 194 II. Diagnosing Lognormality ................................ 200 III. Estimating Population Parameters from Sample Data. ....... 206 IV. HypothesisTesting. .................................... 218 V. Concluding Remarks. ................................... 227 References ..... ....................................... 227 Appendix. ............................................ 231 NutrientTransformations in Soils Amended with Green Manures .. 237 Yadvinder-Singh, Bijay-Singh, and C.S. Khind I. Introduction 238 II. Nutrient Contributions by Green Manures. ............... 239 III. Effect ofGreen Manuring on Chemical and Electrochemical PropertiesofSoils 242 IV. Nitrogen............................................. 249 V. Phosphorus .......................................... 282 VI. Potassium, Calcium, and Magnesium. ................... 287 VII. Sulfur ............................................... 288 VIII. Micronutrients 290 IX. Conclusions.......................................... 296 References. .......................................... 298 Index. .................................................... 311 Contributors M. BECKER, International Rice Research Institute, P.O. Box 933, Manila, Philippines. BENT T. CHRISTENSEN, Askov Experimental Station, Vejenvej 55, DK 6600 Vejen, Denmark. D.J. HORNE, Department of Soil Science, Massey University, Palmerston North, New Zealand. C.S. KHIND, Department of Soils, Punjab Agricultural University, Ludhiana 141 004, India. J.K. LADHA, International Rice Research Institute, P.O. Box 933, Manila, Philippines. R.P. PAREEK, Department of Soil Science, G.B. Pant University for Agriculture and Technology, Pantnagar, India. T.B. PARKIN, U.S. Department of Agriculture, Agricultural Research Service, National Soil Tilth Laboratory, Ames, Iowa 50011, U.S.A. J.A. ROBINSON, The Upjohn Company, Kalamazoo, Michigan, U.S.A. BIJAy-SINGH, Department of Soils, Punjab Agricultural University, Ludhiana 141 004, India. YADVINDER-SINGH, Department of Soils, Punjab Agricultural University, Ludhiana 141 004, India. M.G. WALLIS, Australian Turfgrass Research Institute, P.O. Box 190, Concord West, New South Wales 2138, Australia. Physical Fractionation of Soil and Organic Matter in Primary Particle Size and Density Separates Bent T. Christensen I. Introduction ............................................. 2 A. Soil OrganicMatter (SOM) ............................. 2 B. PhysicalFractionation ofSoils. .......................... 3 II. Soil Fractionation Methodology 4 A. Ultrasonic Dispersion ofSoil. ........................... 5 B. Alternative Dispersion Methods. ........................ 15 C. Density Fractionation.................................. 17 D. Isolation ofSize Separates. ............................. 22 III. Soil OrganicMatter(SOM) in Density Separates.............. 26 A. Light Fractionsfrom Whole Soils. ....................... 26 B. DensimetricAnalysesofSize Separates 35 IV. Chemical CharacteristicsofSOM inSize Separates. ........... 38 A. Distribution ofSOM " .. .... .. 38 B. OrganicConstituents 43 C. OtherChemical Features Related to SOM .. ... . 48 V. DynamicsofSOM in SizeSeparates. ........................ 50 A. Mineralization DuringIncubation 50 B. Stabilization ofDecomposition Products. ................. 56 C. ImpactofCultivation and Agronomy 62 D. Long-term SOMTurnoverStudies InvolvingIsotopes. ..... 66 VI. The UseofSize Separation in Applied Research. ............. 71 VII. FeasibilityofPhysical Soil Fractionation in SOM Studies....... 74 References ................................................... 76 ©1992bySpringer-VerlagNewYorkInc. AdvancesinSoilScience,Volume20