(Downloads - 0)
For more info about our services contact : help@bestpfe.com
Table of contents
A GENERAL INTRODUCTION
A.I THE CHALLENGES OF SUSTAINABLE AGRICULTURE
A.II THE ‘WEEDS TRADE-OFF’
A.II.1 Weeds & crop production
A.II.2 Weed control & environment
A.II.3 Weeds & biodiversity
A.II.4 Summary
A.III APPROACHES TO ALLEVIATE THE ‘WEED TRADE-OFFS’
A.III.1 Overview of the approaches
A.III.2 Integrated Weed Management
A.III.3 Combining high weed diversity with low weed abundance? .
A.III.4 ‘Good’ vs. ‘bad’ weeds?
A.III.5 Favouring weed seed predation
A.III.6 Integration or spatial separation of farming and biodiversity?
A.III.7 Temporal separation of farming and biodiversity?
A.III.8 Crop rotation
A.III.9 Perennial forage crops (PFCs)
A.IV EXPECTED IMPACTS OF PERENNIAL CROPS ON WEEDS
A.IV.1 Literature review
A.IV.1.1 Farmers interview
A.IV.1.2 Regional weed survey
A.IV.1.3 Field experiments
A.IV.1.4 Discussion and limits of the reviewed studies
A.IV.2 Hypothetical mechanisms causing the impacts
A.V DIVERSIFIED CROPPING SYSTEM CONCEPT
A.V.1 Expected impacts on weeds
A.V.2 Expected impacts on biodiversity
A.V.3 Expected impacts on the environment
A.V.4 Expected impacts on crop production
A.VI THE RESEARCH PROJECT
A.VI.1 Objectives and questions
A.VI.2 Structure of the thesis
B OVERWIEW OF THE MATERIALS & METHODS
B.I ANALYZING THE IMPACTS OF TEMPORARY GRASSLANDS ON WEED COMMUNITIES: LARGE-SCALE FIELD SURVEYS
B.I.1 Rationale
B.I.2 Methods in analyzing weed composition and crop rotation histories
B.I.3 Statistical analysis
B.II FIELD EXPERIMENTS ANALYZING THE IMPACTS OF TEMPORARY GRASSLANDS ON WEED POPULATIONS (EPOISSES)
B.II.1 Rationale
B.II.2 Design of the field experiment
B.II.3 Data collection
B.II.4 Statistical analysis
B.III GREENHOUSE EXPERIMENTS ANALYZING THE REGROWTH CAPACITY OF WEED PLANTS AFTER CUTTING
B.III.1 Rationale
B.III.2 Design of the greenhouse experiments
B.III.2.1 Differences between species
B.III.2.2 Plant biomass
B.III.2.3 Plant age
B.III.2.4 Cutting height
B.III.2.5 Interactions between cutting and competition
B.III.3 Cutting treatment and data collection
B.IV FIELD EXPERIMENTS ANALYZING WEED SEED PREDATION
B.IV.1 Rationale
B.IV.2 Measuring weed seed predation
B.IV.3 Design of the seed predation experiments
B.IV.3.1 Weed species
B.IV.3.2 Vegetation cover
C RESULTS (ARTICLES & MANUSCRIPTS)
C.I IMPACTS OF TEMPORARY GRASSLANDS ON WEED COMMUNITIES (CHIZÉ)
C.I.1 Article 1: Meiss, H., Médiène, S., Waldhardt, R., Caneill, J. & Munier-Jolain, N. (2010a) Contrasting weed species composition in perennial alfalfas and six annual crops: implications for integrated weed management. Agron. Sustain. Dev. 30, 657-666. 47
C.I.2 Article 2: Meiss, H., Médiène, S., Waldhardt, R., Caneill, J., Bretagnolle, V., Reboud, X. & Munier-Jolain, N. (2010b) Perennial alfalfa affects weed community trajectories in grain crop rotations. Weed Research 50, 331-340.
C.II EXPERIMENTAL ANALYSES OF THE IMPACTS OF TEMPORARY GRASSLANDS ON WEED POPULATIONS
Manuscript 3: H Meiss, R Waldhardt, J Caneill, N Munier-Jolain (in preparation) Mechanisms affecting population dynamics of weeds in perennial forage crops
C.II.1 Introduction
C.II.2 Methods
C.II.2.1 Experimental design
C.II.2.1.1 Weed seed addition
C.II.2.2 Measurements
C.II.2.2.1 Plant densities
C.II.2.2.2 Biomass
C.II.2.2.3 Chemical soil parameters
C.II.2.3 Statistical analysis
C.II.2.3.1 Emerged weed densities
C.II.3 Results
C.II.3.1 Dynamics of emerged weeds
C.II.3.1.1 Dynamics of weed plant density and diversity
C.II.3.1.2 Dynamics of weed community composition
C.II.3.1.3 Dynamics of individual weed species
C.II.3.1.4 Effect of weed seed addition
C.II.3.1.5 Dynamics of weed and crop biomass
C.II.4 Discussion
C.II.4.1 Differences between crop treatments
C.II.4.1.1 Plant densities
C.II.4.1.2 Species composition
C.II.4.2 Grassland management practices
C.II.4.2.1 Sowing date
C.II.4.2.2 Crop species
C.II.4.2.3 Cutting frequency
C.II.4.3 Underlying mechanisms
C.II.4.3.1 Soil tillage (A)
C.II.4.3.2 Competition (B)
C.II.4.3.3 Hay cuttings (C)
C.II.4.3.4 Interactions between the three factors
C.II.4.4 Strength, limits, perspectives and preliminary recommendations
C.III REGROWTH AFTER CUTTING
C.III.1 Article 4: Meiss, H., Munier-Jolain, N., Henriot, F. & Caneill, J. (2008b) Effects of biomass, age and functional traits on regrowth of arable weeds after cutting. J. Plant Dis. Prot. XXI, 493-499.
C.III.2 Article 5: Meiss, H., Bonnot, R., Strbik, F., Waldhardt, R., Caneill, J. & Munier-Jolain, N. (2009) Cutting and competition reduce weed growth: additive or interactive effects? XIIIth International Conference on Weed Biology, Dijon, 28-37.117
C.IV WEED SEED PREDATION
C.IV.1 Article 6: Alignier, A., Meiss, H., Petit, S. & Reboud, X. (2008) Variation of post-dispersal weed seed predation according to weed species, space and time. J. Plant Dis. Prot., XXI, 221-226.
C.IV.2 Article 7: Cordeau, S.; Meiss, H.; Boursault, A. (2009) Bandes enherbées: Quelle flore, quelles prédateurs, quelle prédation? XIIIth International Conference on Weed Biology, Dijon, 50-59.
C.IV.3 Article 8: Meiss, H., Lagadec, L. L., Munier-Jolain, N., Waldhardt, R. & Petit, S. (2010c) Weed seed predation increases with vegetation cover in arable fields. Agric. Ecosyst. Environ. 138, 10-16.
D GENERAL DISCUSSION
D.I EVIDENCE OF THE IMPACTS OF PFCS ON WEEDS
D.I.1 Differences in species composition between current crops
D.I.2 Weed community trajectories during crop rotations
D.I.3 Weed population dynamics under various crop management practices in the small-scale field experiment
D.I.4 Comparison of weed species reactions between the large-scale surveys and the small-scale field experiment
D.I.5 Functional groups
D.I.5.1 Annual vs. perennial weed species
D.I.5.2 Small vs. tall or climbing species
D.I.5.3 Grasses vs. broadleaved species
D.I.6 Weed abundance and diversity
D.I.7 Conclusion: PFCs, useful tools for Integrated Weed Management .
D.II UNDERLYING MECHANISMS
D.II.1 Absence of soil tillage (A)
D.II.2 Competition (B)
D.II.3 Hay cuttings (C)
D.II.4 Interactions between cuttings and competition (B*C)
D.II.5 Seed predation (D)
D.II.6 Overview of the underlying mechanisms
D.III PERSPECTIVES: PREDICTING THE IMPACTS OF PFCS
D.III.1 Mechanistic models
D.III.2 Predicting weed regrowth after cutting
D.III.3 Factors determining weed seed predation
D.IV GENERAL CONCLUSION
E CITED REFERECES
