DEVANT L' INSTITUT NATIONAL POLYTECHNIQUE DE TOULOUSE

Examinateur Guiresse

Description

Niveau: Supérieur, Doctorat, Bac+8
THESE PRESENTEE DEVANT L' INSTITUT NATIONAL POLYTECHNIQUE DE TOULOUSE EN VUE DE L'OBTENTION DU DIPLOME : DOCTORAT ECO ET AGROSYSTÈMES PAR MIGUEL ANGEL TABOADA COMPORTEMENT DE LA STRUCTURE DES SOLS DE LA PAMPA INONDABLE ET DE LA PAMPA AGRICOLE DE L'ARGENTINE (EN ANGLAIS) (SOIL STRUCTURAL BEHAVIOUR IN FLOODED AND AGRICULTURAL SOILS OF THE ARGENTINE PAMPAS) Soutenue le 30 mai 2006 devant la Commission d'Examen Dr. J. C. REVEL Président Dr. M. GUIRESSE Examinateur Dr. P. BOIVIN Rapporteur examinateur Dr. A. BRUAND Dr. M. KAEMMERER Directeur de Thèse

• pampa


• flooding pampa


• experimental design


• shrinkage curves


• soil physical


• general concluding


• bruand dr.


• interactive effects


• study area

Sujets

• Institut national polytechnique de Toulouse
• Design of experiments

Informations

• Publié par: profil-zyak-2012
• Publié le: 01 mai 2006
• Nombre de lectures: 13
• Langue: English
• Poids de l'ouvrage: 4 Mo

Extrait

THESE


PRESENTEE


DEVANT L’ INSTITUT NATIONAL POLYTECHNIQUE
DE TOULOUSE

EN VUE DE L’OBTENTION

DU DIPLOME :

DOCTORAT ECO ET AGROSYSTÈMES

PAR

MIGUEL ANGEL TABOADA


COMPORTEMENT DE LA STRUCTURE DES SOLS
DE LA PAMPA INONDABLE ET DE LA PAMPA
AGRICOLE DE L’ARGENTINE (EN ANGLAIS)

(SOIL STRUCTURAL BEHAVIOUR IN FLOODED
AND AGRICULTURAL SOILS OF THE ARGENTINE
PAMPAS)


Soutenue le 30 mai 2006 devant la Commission d’Examen

Dr. J. C. REVEL Président

Dr. M. GUIRESSE Examinateur
Dr. P. BOIVIN Rapporteur examinateur A. BRUAND M. KAEMMERER Directeur de Thèse GENERAL INDEX
page
SUMMARY 1
RESUMÉ 2
RESUMEN 3
1. BIBLIOGRAPHICAL UPDATE
1.1. Genesis of Pampas soils
1.1.1. Geology and geomorphology of the Pampas region 4
1.1.2. Climate 8
1.1.3. References 10
1.2. Studied Pampas subregions
1.2.1. Detailed description of the flooding Pampa 15
1.2.2. Detailed description of the rolling Pampa 19
1.2.3. References 21
1.3. Soil structural behaviour
1.3.1. The aggregation – disaggregation equilibrium 33
1.3.2. Definition of form, stability and resilience 34
1.3.3. Creation of soil structure 41
1.3.4. References 45
1.4. Challenges to be addressed in the study regions
1.4.1. Description of still unsolved problems 59
1.4.2. References 61
2. GENERAL OBJECTIVES AND HYPOTHESIS
2.1. Objectives 63
2.2. Hypothesis 64
3. SOILS OF THE FLOODING PAMPA
3.1. Specific antecedents
3.1.1. Brief characterization of the study region 65
3.1.2. Theoretical impact caused by trampling by
domestic stock. 65
3.1.3. References 66
3.2. Specific objectives and hypothesis 69
3.3. Study area and methods
3.3.1. Study area 70
3.3.2. Experimental design and sampling 71
3.3.3. References 72
3.4. Soil volumetric changes in a Typic Natraquoll
3.4.1. Introduction 81
3.4.2. Materials and methods 82
3.4.3. Results and discussion 83
3.4.4. Conclusions 84
3.4.5. References 87
3.5. Grazing effects of the bulk density in a Natraquoll
3.5.1. Introduction 97
3.5.2. Materials and Methods 98
3.5.3. Results and Discussion 100
3.5.4. Conclusions 103
ii3.5.5. References 103
3.6. Influence of cattle trampling on soil porosity under
alternate dry and ponded conditions
3.6.1. Introduction 111
3.6.2. Materials and methods 112
3.6.3. Results 113
3.6.4. Discussion 115
3.6.5. Conclusions 116
3.6.6. References 117
3.7. Interactive effects of exchangeable sodium
and water content on soil modulus of rupture
3.7.1. Introduction 124
3.7.2. Materials and methods 125
3.7.3. Results and discussion 126
3.7.4. References 128
3.8. Structural stability changes in a grazed
grassland Natraquoll
3.8.1. Introduction 131
3.8.2. Material and methods 131
3.8.3. Results and discussion 133
3.8.4. References 138
3.9. Soil and vegetative changes associated
with the replacement of native grasslands
by sown pastures
3.9.1. Introduction 145
3.9.2. Study area 146
3.9.3. Methods 148
3.9.4. Statistics 149
3.9.5. Results and discussion 149
3.9.5. Conclusions 153
3.9.6. References 154
3.10. Soil volumetric changes in natric soils caused
by air entrapment following seasonal ponding and
water table rises
3.10.1. Introduction 167
3.10.2. Shrinkage curves and shrinkage indices 168
3.10.3. Material and Methods 169
3.10.4. Results and discussion 172
3.10.5. References 178
3.11. Concluding remarks on Flooding Pampa
soils 192
4. SOILS OF THE ROLLING PAMPA
4.1. Specific antecedents
4.1.1. Their distinctive features: the mollic
epipedon and the argillic horizon 196
4.1.2. Soil physical degradation and its
causes in the rolling Pampa 200
4.1.3. The adoption of zero tillage systems 202
iii4.1.4. Soil aggregation mechanisms 203
4.1.5. References 204
4.2. Specific objectives and hypothesis 213
4.3. Study areas and methods
4.3.1. Experimental sites 214
4.3.2. References 216
4.4. Comparison of compaction induced by
conventional and short-term zero tillage
in two soils
4.4.1. Introduction 219
4.4.2. Materials and Methods 221
4.4.3. Results and discussion 223
4.4.4. Conclusions 228
4.4.5. References 229
4.5. Soil physical properties and soybean
(Glycine max, Merrill) root abundance in
conventionally- and long-term zero-tilled soils
4.5.1. Introduction 237
4.5.2. Materials and Methods 239
4.5.3. Results and discussion 242
4.5.4. Conclusions 248
4.5.5. References 248
4.6. Distribution and abundante of maize
roots (Zea mays L.) in Pampean Argiudolls
under different tillage systems
4.6.1. Introduction 263
4.6.2. Materials and methods 265
4.8.3. Results and discussion 266
4.6.4. Conclusions 270
4.6.5. References 271
4.8. Mechanisms of aggregation in a
silty loam under different simulated
management regimes
4.8.1. Introduction 280
4.8.2. Materials and Methods 281
4.8.3. Results 284
4.8.4. Discussion 288
4.8.5. Conclusions 292
4.8.6. References
4.8. Clod shrinkage indices and cracking
in a silty loam under different simulated
management regimes
4.8.1. Introduction 307
4.8.2. Materials and methods 309
4.8.3. Results and Discussion 312
4.8.4. References 316
iv
4.9. Concluding remarks on rolling Pampa soils
4.9.1. Soil physical behaviour under zero tillage 333
4.9.2. Soil aggregation mechanisms 335
5. GENERAL CONCLUDING REMARKS 339
vLIST OF TABLES

Table 1.1.1. Generalized stratigraphy of the Pampas region (taken from M.
Turner 1975, in Instituto Nacional de Tecnología Agropecuaria 1989).

Table 1.3.1. Biotic and abiotic influences on soil structure (Oades 1993)

Table 3.3.1. Soil horizons sequence and morphological description of soil profile.

Table 3.3.2. Linear functions fitted to matric potential (ψ) logaritms and
gravimetric water content (θ ) in each identified horizon (Lavado and Taboada w
1988). R = coefficient of linear correlation.

Table 3.3.3. Soil chemical properties in the three upper horizons.

Table 3.4.1. Soil organic carbon (org C), humic acids (HA) and fulvic acids (FA),
total clay and estimated proportion of expansible clay contents. Soil water
retention at – 33.3 kPa matric potential (θ -33.3 kPa), upper plastic limit (UPL) w
and lower plastic limit (LPI) and plasticity index in the study soil.

Table 3.4.2. Soil pore volume, volumetric water content (θ ), and pore volume to v
water content volume quotient, in sampling dates with ponding.

Table 3.4.3. Mean swell – shrink indices (SSI) in undisturbed and disturbed
samples and SAR values in which SSI was measured.

Table 3.5.1. Soil surface strength as measured by the penetrometer in 1984.

Table 3.5.2. Bulk density in 4-cm layers of the A1 horizon.
Table 3.6.1: Linear regressions between soil water content and total porosity.
Standard errors are in parentheses.

Table 3.6.2: Aggregate mean weight diameter after wet-sieving in summer
(December 1986) and winter (July 1987).

Table 3.8.1. Distribution of the mean percentage of water-stable aggregates by
size in the grazed and the old exclosure areas. Standard error values are
between parenthesis.

Table 3.9.1. Description of the studied soil types and associated floristic
composition.

Table 3.9.2. Components of the ground basal cover in the untilled (UT) and tilled (T)
fields (means and standard errors).

Table 3.9.3. Particle-size analysis, organic carbon (OC), pH in paste, sodium
adsorption ratio (SAR) and soil salinity as measured by its electrical conductivity
(EC) in the untilled (UT) and the tilled (T) top horizons. Means and standard errors.

Table 3.10.1: indices and related variables from the shrink data of
vinatural soil clods (Mc Garry and Daniells, 1987).

Table 3.10.2: Soil properties in surface (Ah and E) and Bt horizons of the studied
soils.

Table 3.10.3. Shrinkage indices in clods of surface and Bt horizons of the soils of
sites A and site B.

Table 3.10.4. Shrinkage indices in field soil cores of surface and Bt horizons of the
Chelforó (Mollic Natraqualf) and the Guido (Typic Natraquoll) soils, and percentage
variations of these indices (∆%) from the clods to the field.

Table 3.10.5: soil specific volume (ν), volumetric water content (θ ) and the specific v
volume of air filled pores (P) in the Ah horizon of the Guido soil, as a result of
surface ponding (field experiment) and capillarity moistening.

Table 4.4.1. Soil organic carbon (org C) and relative compaction (RC= field bulk
density / maximum density in Proctor test) in conventionally tilled (CT) and zero
tilled (ZT) plots of the Bragado and the Peyrano soils.

Table 4.5.1. Topsoil