POLYGENETIC OXISOLS ON TERTIARY SURFACES, MINAS GERAIS, BRAZIL Soil genesis and landscape development Cristine CaroleMuggie r Promotor: Dr.N .va nBreemen , hoogleraar ind eBodemvormin g enEcopedologi e Co-promotor: Dr.ir .P .Buurman , universitairhoofddocent , Departement Omgevingswetenschappen POLYGENETIC OXISOLS ON TERTIARY SURFACES, MINAS GERAIS, BRAZIL Soil genesis and landscape development CristineCarol eMuggie r Proefschrift ter verkrijging van de graad van doctor op gezag van de rector magnificus van de Landbouwuniversiteit Wageningen, Dr. C.M.Karssen , in het openbaar te verdedigen op maandag 14septembe r 1998 des namiddags te vier uur in deAul a CIP-GEGEVEfNS KONINKLIJKE BIBLIOTHEEK, DEN HAAG Muggier, C.C. Polygenetic Oxisols on Tertiary surfaces, Minas Gerais, Brazil. Soil genesis and landscape development/ C. C. Muggier, - [S.I.: s.n.]. - III. PhD thesis Wageningen. - With ref. - With summary in Dutch and Portuguese. Subject headings: Oxisols, soil genesis; polygenetic soils; soil- landscape; Brazil. ISBN 90-5485-907-5 BIBLIOTHEEK LANDBOUWUNIVERSITEIT WAGENTNGEN To all people committed to build a better world for everybody The research reported in this thesis was sponsored by CAPES/Ministry of Education of Brazil and Federal University of Viçosa, Minas Gerais, Brazil, as a full Ph.D. training programme. Cover layout by Celso Marcatto and Renato Roscoe Drawing by Renato Roscoe FOREWORD By the time of my undergraduation, I was often struck by the impressive landscape around SâoJoà o delRei , along with itsquartziti c chains, sets ofconve x hills andhug egullies . During myM.Sc . course in Lavras, I happened to make visits to this neighboring area, asa geological consultant, with mysuperviso r Prof. Nikon Curi and other students. Onthes e field trips, we discussed the landscape, the parent materials and the resulting soils, which are sometimes much shallower than expected. From these discussions it became clear that the genesis ofthes e soils andrelate d landscapes deserved much more attention than they had had previously. This situation couldb edesigne d into aninterestin g problem fora Ph.D . research. Since I had heard about the existence of a chair in tropical soils and about an international soil museum in Wageningen, I was already interested in going there to study. Wageningen also appeared to bever y attractive because ofth e useo f English asth e working language inth euniversity , andth epresenc e ofa Departmen t ofEcologica l Agriculture, where myhusban d Celso could also pursue aM.Sc . degree. Ona mor e personal basis, going to study in TheNetherland s would fulfill mycuriosit y to experience myEuropea n roots. All of these factors proved to be only partially correct, andt o come to Wageningen wasno t an easy task. But, since life sometimes turns out all right even after taking what seem to be "wrong" shortcuts, I amhapp y to have hadth e opportunity to study and live inWageninge n for some years. Some people were of great help in this: Nilton Curi, Mauricio Fontes, Liovando Marciano, José Machado, Joào Bertoldo, Rosivaldo. I thank them all for their share in this effort. In Wageningen, at the Department of Soil Science and Geology (now Laboratory of Soil Science and Geology), Nico van Breemen accepted to be my promotor and Peter Buurman became myco-promoto r and direct supervisor. Peter was always very interested in my research, pushing meforwar d and encouraging met o go on, even when sometimes Iwa s about to clash with apparently unsolvable problems. Histalen t to make a synthesis ofa wealth of information and to come out with simple and consistent concepts always amazed me. I thank himver y much for hisguidanc e and friendship during allthes e years. Duet o the nature of my research, I had less contact with Nico van Breemen in the first three years. Even so, every nowan dthe n hepushe d met o stick to myrea l problem through his valuable comments. I took some time to experience the meaning of "Breemenization" of a manuscript, which proved to be a great discovery: Nico's clear and consistent scientific reasoning contributed remarkablyt o improving mywritin g andgav e mea stron g confidence tog oon . Thanks! I also thank my co-authors Jan van Loef, Ed Meijer, Tom Pape, and Corine van Griethuysen for their contributions to this thesis. I am grateful to Toine Jongmans for his guidance inm yearl y steps inmicromorphology , hisassistanc e whenever needed, and forth e relaxed chatsw eha damon gth emicroscopes . In 1996,1me tProf . Georges Stoops forth e first time during a training course in micromorphology in Gent, Belgium. His experience with tropical soils andhi sexpertis e inmicromorpholog y areremarkabl e andopene d myeye s tothi s new and fascinating micromorphological world. Georges Stoops gave valuable support tom y work, always ready to answer or discuss any of my questions and to help with the characterization of the intricate unfamiliar features I found at each new sequence. I thank him very much for his kindness to me and for the stimulating discussions we had in the last two years. Most of myresearc h was conducted at the Laboratory of Soil Science and Geology in Wageningen, apart from twofield trip s to Brazil. Of allth e people working at the Laboratory, I have a special word of thanks for Jan van Doesburg, who helped me a great deal with XRD determinations and other laboratory routines. Ton Engelsma introduced me to the 'dry' laboratory in early times; Corine van Griethuysen and Tom Pape did most of the laser grain- sizing determinations; Bram Kuyper, and later Jan Huttink, took care of the XRF analyses; Arie van Dijk prepared the thin sections for micromorphology; and Barend, Eef, Frans, and Nieltje from the chemical ('wet') laboratory did the routine analyses and assisted me in other chemical analysis. Claudio Brustolini from the Laboratory of Soil Physics at the Federal University ofViços atoo k care ofpreparatio n and texture determination of part ofth e samples. Hetti Leferink from PCM was a great help inteachin g me about the preparation of samples for TEM and the use of it -what a nightmare of work! I am grateful to all of them for their share and helpdurin gthi sresearch . Field work in Brazil was made possible due to the organization and supportive work done by Luiz Fontes, Nilton Curi, and Luiz Marcelo Aguiar Sans. The synthesis of the geomorphological knowledge and itsfield aspect s could not have been completed without the valuable contribution of Prof. Dr. Alaoua Saadi from the Institute of Geosciences at the Federal University of Minas Gerais. Alaoua kindlyjoine d one of thefield trip s to show us the main neotectonic evidences in the area of Sào Joâo del Rei, when he provided us with a very sound explanation of the Cenozoic evolution of the landscape. I am very pleased with all of thesecontributions . My study for the Ph.D. has only been possible through the support offered by my department at the Federal University of Viçosa. I am deeply grateful to my colleagues and friends at the department who were always encouraging and helpful. Some of them were especially important: Luiz Fontes, who took care of all the red tape during my absence, facilitated things as much as he could every time it was needed, and above all for his unwaveringfriendship. Iren e Maria Cardoso took the onus of taking on my former activities and classes during my absence, not to mention that her close friendship provided me with positive encouragement all the time. Mauricio Fontes also assumed part of my activities, besides providing assistance every time I needed it. Furthermore, I acknowledge the assistance of Sonia do Carmo Almeida and the staff of the Assessoria de Assuntos Internacionais who took care of the administrative aspects of my leave. In Wageningen, the administration of the Laboratory of Soil Science and Geology aswel l asth e Dean's Office for International Students were of great help in the administrative aspects of my research, bureaucratic procedures and practical arrangements ofm ystay . Upon myarriva l to the Department, I had the good fortune to share an office with Else Henneke: Ilearn t from her all about the department functioning and she helped me agrea t deal with the translation of correspondence and messages sent to me in Dutch. Else was always available and willing to help mege t through all sorts of difficulties. With Leo Tebbens I could share views of life, science, cultural differences and many more things during very pleasant, sometimes extended, coffee breaks. Other peoplewer ever ywillin gt o help mewit h all kinds of problems and difficulties when asked; I would like to mention Marcel Lubbers, Salle Kronenberg, Hans Huisman, Hugo van der Gon, Rienk Miedema, and Tini van Mensvoort. Theforeig n group in the department provided a pleasant interaction, funny moments and tasty international dinners during early times of my stay. Unfortunately it shrank very much in the last years and Imisse d quite alo t thepresenc e ofJorge , Virginie, Ioulia, Gandah, Minh, among others. However, a former student of mine, Renato, started his Ph. D. recently and we have been able to enjoy very nice and motivating chats during coffee breaks and other times. The artistic skills of Renato that were previously unknown to me made a decisive contribution to the cover of this thesis. Renato spent many days together with Celso developing and taking care of the final layout. Also, Fayez whofinished hi sthesi s shortly before mewa s very helpful inprovidin g mewit h all sort oftip sabou t thefina l arrangements for the printing ofm ythesis . Besides the research itself, a Ph. D. leave abroad is a lifelong experience and develops into a history where many people leave their marks.