Diversifying crop rotations with temporary grasslands - Université de ...

More documents

Recommendations

Info

impacts on several phases of the weed life cycle (see general introduction). One rather unknown mechanism is weed seed predation, i.e. the consumption of weed seeds by animals. Weed seed predation has very recently gained much interest in agronomic and ecological research. It may have very strong impacts on weed population dynamics making it interesting for Integrated Weed Management (Westerman et al., 2005). On the other hand, favouring weed seed predation may be favourable to seed eating organisms and enhance farmland biodiversity at several trophic levels. In PFCs, weed seed predation might be favoured by three mechanisms. i) The absence of soil tillage prevents weed seeds to be buried in the soil. Thus all newly produced weed seeds stay on the soil surface where they are more accessible to seed predators. ii) Reduced applications of pesticides in PFCs compared to annual crops may be favourable to predatory organisms. iii) The permanent vegetation cover as well as the absence of soil tillage create a more stable habitat that may be preferred by seed eating animals over annual crops. Weed seed predation might thus cause parts of the differences in weed communities between annual and perennial crops observed in the weed surveys in the Chizé region, the field experiment and in previously published studies. Several experimental studies were conducted to investigate (1) whether seed predation rates differ between common annual weed species and (2) to analyse the impact of vegetation cover. B.IV.2 Measuring weed seed predation Weed seed predation was measured using ‘seed cards’ (Westerman et al., 2003a) consisting by seeds slightly glued to sandpaper strips that were fixed on the soil surface with nails. Two types of negative controls were used: (A) Seed cards were put into total exclusion cages (boxes made from metal wire gauze with 1 mm × 1 mm mesh size) permeable to wind and rain excluding any type of seed predator. (B) Presenting plastic beads instead of weed seeds. Moreover, vertebrate exclusion cages (boxes made from metal fence wire with 12 mm × 12 mm mesh size) were used in the 2008 experiment to separate predation by vertebrates and invertebrates (see Article 8). 45
B.IV.3 Design of the seed predation experiments B.IV.3.1 Weed species Differences in seed predation rates between weed species were tested in 2007 in an organic wheat field near Dijon and in 2008 on the different plots of the Epoisses field experiment described in Manuscript 3. In both experiments, seed predation rates were compared for seven common annual weed species, chosen from the 17 weed species sown in the Epoisses field experiment (compare Table 2 of Article 6 and Table 7 of Manuscript 3). B.IV.3.2 Vegetation cover The impact of vegetation cover on weed seed predation was tested in 5+ crop treatments of the field experiment described in Manuscript 3. These crop treatments were chosen (i) to represent a wide gradient of vegetation cover from bare soil to uncut perennial crops, (ii) to find out whether the quality of the vegetation (grass vs. legume crop) or the vegetation quantity (cut vs. uncut plots) is more important for seed predation rates. The experiments were repeated at three different periods (April, Mai and July 2008). Three weed species were tested at all periods, seven species at one period (July). In the July trial, two additional treatments were included: mown and unmown field margin strips, that were located on the same experimental farm in Epoisses close to the experimental field (Article 7). For each period, weed species, crop treatment and exclusion treatment, 4 spatial repetitions were used. 46
Page 1 and 2:
Diversifying crop rotations with te
Page 3 and 4:
In Chizé, I am indebted to all the
Page 5 and 6:
Talks . ...........................
Page 7 and 8:
C.II.4.1 Differences between crop t
Page 9 and 10:
INDEX OF FIGURES Fig. 1: Population
Page 11 and 12:
ABSTRACTS (ENGLISH, FRENCH & GERMAN
Page 13 and 14:
Extended summary in English Résum
Page 15 and 16:
Extended summary in English Résum
Page 17 and 18: CONTEXT AND FUNDING This thesis is
Page 19 and 20: THESIS ORGANISATION This thesis ent
Page 21 and 22: 8) Meiss, H., Lagadec, L. L., Munie
Page 23 and 24: Posters . 1) Meiss, H., Waldhardt,
Page 25 and 26: 2007). Agriculture is increasingly
Page 27 and 28: term considerations (Munier-Jolain
Page 29 and 30: problematic for the production of d
Page 31 and 32: Newton, 2004). Several bird species
Page 33 and 34: A.III APPROACHES TO ALLEVIATE THE
Page 35 and 36: and higher production costs or even
Page 37 and 38: competitive yield loss (Cousens, 19
Page 39 and 40: 2006; Makowski et al., 2007). Moreo
Page 41 and 42: Table 3: Four strategies for combin
Page 43 and 44: otations is thus an obvious approac
Page 45 and 46: iv) the availability of cheap and e
Page 47 and 48: Clay & Aguilar (1998) compared the
Page 49 and 50: Heggenstaller & Liebman (2006) comp
Page 51 and 52: growth of any (crop or weed) plant
Page 53 and 54: A.V DIVERSIFIED CROPPING SYSTEM CON
Page 55 and 56: crops will thus probably show rathe
Page 57 and 58: annual crops while increasing organ
Page 59 and 60: • Which species are suppressed, w
Page 61 and 62: B OVERWIEW OF THE MATERIALS & METHO
Page 63 and 64: A) France B) Study site ~1000 km Pe
Page 65 and 66: perennial crops with different mana
Page 67: B.III.2.4 Cutting height In 2008, t
Page 71 and 72: Agron. Sustain. Dev. 30 (2010) 657-
Page 73 and 74: Contrasting weed species compositio
Page 79 and 80: Mean frequency in perennial lucerne
Page 81 and 82: C.I.2 Article 2: Meiss, H., Médiè
Page 83 and 84: 332 H Meiss et al. communities (Boo
Page 85 and 86: 334 H Meiss et al. functional group
Page 87 and 88: 336 H Meiss et al. Table 3 Indicato
Page 89 and 90: 338 H Meiss et al. Relative frequen
Page 91 and 92: 340 H Meiss et al. MEISS H, MUNIER-
Page 93 and 94: perennial crop treatments, differen
Page 95 and 96: PFCs might inhibit the successful g
Page 97 and 98: during winter), T10 without soil ti
Page 99 and 100: The viability and germination abili
Page 101 and 102: Table 8: Organic carbon and total n
Page 103 and 104: The development of weed species ric
Page 105 and 106: C.II.3.1.2 Dynamics of weed communi
Page 107 and 108: C.II.3.1.3 Dynamics of individual w
Page 109 and 110: Time Fig. 14: Temporal development
Page 111 and 112: At the end of the experiment in spr
Page 113 and 114: Difference sown - unsown (plants m
Page 115 and 116: Cumulated BM production (g m -2 ) 1
Page 117 and 118: Weed biomass (g m -2 ) 500 400 300
Page 119 and 120:
Table 12: Factors differing between
Page 121 and 122:
However, some differences in densit
Page 123 and 124:
Table 13: Mechanisms causing the im
Page 125 and 126:
2007 and 2008, while big numbers of
Page 127 and 128:
• Weed biomasses decreased in sum
Page 129 and 130:
Our results show that different mec
Page 131 and 132:
including exotic species (Palmer an
Page 133 and 134:
01234568912661943 ! "#$$%&' ()123)4
Page 135 and 136:
332 3 v77yDDI7FA7D9CyVuB69f7F6BIDI7
Page 137 and 138:
$%%524!'276372224274222489 00123452
Page 139 and 140:
0123156789153263616 52675!6253!1!"5
Page 141 and 142:
XIII ème COLLOQUE INTERNATIONAL SU
Page 143 and 144:
irradiation,…), and (ii) biotic i
Page 145 and 146:
Table I: Species included in the ex
Page 147 and 148:
Fig. 2: Mean biomass (harvestable d
Page 149 and 150:
When both treatments were combined,
Page 151 and 152:
C.IV WEED SEED PREDATION C.IV.1 Art
Page 153 and 154:
99"268)3635683498354836792666676983
Page 155 and 156:
001234564787938494694783 777787946!
Page 157 and 158:
001234564787938494694783 34564789@A
Page 159 and 160:
XIII ème COLLOQUE INTERNATIONAL SU
Page 161 and 162:
produites restent à la surface du
Page 163 and 164:
Tableau 1 : Liste des espèces adve
Page 165 and 166:
Insectes prédateurs Les principaux
Page 167 and 168:
C.IV.3 Article 8: Meiss, H., Lagade
Page 169 and 170:
Table 1 Studies investigating the i
Page 171 and 172:
Table 2 Overview showing (i) mean s
Page 173 and 174:
higher weed seed losses (e.g., Mena
Page 175 and 176:
D GENERAL DISCUSSION Data from weed
Page 177 and 178:
The first two limits could be addre
Page 179 and 180:
composition that may be compared to
Page 181 and 182:
Frequency in field experiment (Epoi
Page 183 and 184:
crops (Clay and Aguilar, 1998; Card
Page 185 and 186:
Such diversified crop rotations cou
Page 187 and 188:
the leaves (needed for photosynthes
Page 189 and 190:
field margin strips (compare Articl
Page 191 and 192:
1) The absence of soil tillage and
Page 193 and 194:
D.III.2 Predicting weed regrowth af
Page 195 and 196:
Future studies must determine the s
Page 197 and 198:
(illustrated in Fig. 24). Later, re
Page 199 and 200:
D.III.3 Factors determining weed se
Page 201 and 202:
governing the presence and abundanc
Page 203 and 204:
natural conditions, weed species po
Page 205 and 206:
This PhD research project documente
Page 207 and 208:
area needed for crop production. Gl
Page 209 and 210:
seed characteristics, tillage and s
Page 211 and 212:
Fried G., S. Petit, F. Dessaint, X.
Page 213 and 214:
at the Eastern base of the Meissner
Page 215 and 216:
Lindegarth M., L. Gamfeldt. (2005)
Page 217 and 218:
Murphy S.D., D.R. Clements, S. Bela
Page 219 and 220:
affected by experimental substrate.
Page 221 and 222:
Vincent G., M. Ahmim. (1985) Note o
Page 223 and 224:
ANNEXES ANNEXE 1: KEY WORDS IN ENGL
Page 225 and 226:
genetically modified crop varieties
Page 227 and 228:
ANNEXE 3: WEED SPECIES OF THE LARGE
Page 229 and 230:
Name of species /genera Code Freq.
Page 231 and 232:
Name of species /genera Code Freq.
Page 233 and 234:
ERKLÄRUNG (DECLARATION FOR THE GIE
show all

Diversifying crop rotations with temporary grasslands - Université de ...

Create successful ePaper yourself

Delete template?

Save as template?