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\sbasedon0 \snext32 Texte de bulles;}}{\*\revtbl {Unknown;}{Marion;}}{\info{\title Preparation and submission of extended ab-stracts for the Joint Organic Congress 2006}{\author lel}{\operator Marion}{\creatim\yr2006\mo2\dy27\hr15\min12}{\revtim\yr2006\mo2\dy27\hr15\min12}
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Incidence of limiting factors on organic winter wheat performance
\par
\par }\pard\plain \s16\qc \li0\ri0\keepn\widctlpar\aspalpha\aspnum\faauto\outlinelevel1\adjustright\rin0\lin0\itap0 \f29\fs24\lang1030\langfe1030\cgrid\langnp1030\langfenp1030 {\fs20\lang2057\langfe1030\langnp2057
M. Casagrande, C. David, M. Valantin-Morison, and M. H. Jeuffroy
\par
\par }\pard \s16\ql \li0\ri0\keepn\widctlpar\aspalpha\aspnum\faauto\outlinelevel1\adjustright\rin0\lin0\itap0 {\lang2057\langfe1030\langnp2057
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\b\f29\fs14\lang2057\langfe1030\cgrid\langnp2057\langfenp1030 {\i Abstract \endash }{French organic farmers are asked to i}{n}{crease Grain Protein Content (GPC) of organic winter wheat to guarantee
the breadmaking quality required from millers. Facing with the recent depletion of o}{r}{ganic products, farmers also need to stabilize and increase the yield performance. The aim of our study is to give the explanations of the yield and GPC var}{i}{
ability generally observed in organic produ}{c}{tion. A diagnostic method will be implemented on a network of ca. 10 fields per year during two crop years added with previous field network (77 fields) and exper}{i}{
ments (4 experiments on cultivars). We will unde}{r}{stand yield and GPC performance from environmental and agronomic conditions and relate the observed limiting factors with crop management, climatic co}{n}{
ditions and characteristics of the cropping systems.}{\cs21\super \chftn {\footnote \pard\plain \s22\ql \li0\ri0\sl160\slmult0\widctlpar\tx240\aspalpha\aspnum\faauto\adjustright\rin0\lin0\itap0 \f29\fs12\lang1030\langfe1030\cgrid\langnp1030\langfenp1030 {
\lang2057\langfe1030\langnp2057 M. Casagrande is with the INRA, UMR Agronomy, INRA-INA PG, BP01, 78850 Thiverval-Grignon, France (mcas}{\lang2057\langfe1030\langnp2057 a}{\lang2057\langfe1030\langnp2057 grande@grignon.inra.fr).
\par \tab C. David is with ISARA-Lyon, 69288 Lyon cedex 02, France (d}{\lang2057\langfe1030\langnp2057 a}{\lang2057\langfe1030\langnp2057 vidc@isara.fr).
\par \tab M. Valantin-Morison is with the INRA, UMR Agronomy, INRA-INA PG, BP01, 78850 Thiverval-Grignon, France (mor}{\lang2057\langfe1030\langnp2057 i}{\lang2057\langfe1030\langnp2057 son@grignon.inra.fr).
\par \tab M.H. Jeuffroy is with the INRA, UMR Agronomy, INRA-INA PG, BP01, 78850 Thiverval-Grignon, France (jeu}{\lang2057\langfe1030\langnp2057 f}{\lang2057\langfe1030\langnp2057 froy@grignon.inra.fr).}}}{
\par
\par }\pard\plain \s19\qc \li0\ri0\sa40\sl220\slmult0\keepn\widctlpar\aspalpha\aspnum\faauto\outlinelevel0\adjustright\rin0\lin0\itap0 \scaps\f29\fs18\lang2057\langfe1030\cgrid\langnp2057\langfenp1030 {Introduction
\par }\pard\plain \s18\qj \li0\ri0\sl220\slmult0\widctlpar\aspalpha\aspnum\faauto\widctlpar\aspalpha\aspnum\faauto\pnrdate0\pnrnot1\adjustright\rin0\lin0\itap0 \f29\fs16\lang2057\langfe1030\cgrid\langnp2057\langfenp1030 {
The low organic wheat grain yields (4,4 t/ha on average in 2004, in }{\field\fldedit{\*\fldinst {
ADDIN EN.CITE Agence Bio2005251Agence Bio,2005L'agriculture biologique fran
çaise. Chiffres 2004Agence Française pour le Développement et la Promotion de l'Agriculture Biologique126}}{\fldrslt {Agence Bio, 2005)}}}{ are esse}{n}{
tially explained by several factors such as nitrogen (N) deficiency, water deficit, weeds, pests and di}{s}{eases or compacted soil structure }{\field\fldedit{\*\fldinst {
ADDIN EN.CITE David2004240Christ
ophe DavidPhilippe ViauxJean-Marc Meynard2004Les enjeux de la production de blé tendre biologique en FranceLe Courrier de l'Environnement de l&apos
;
INRA5143-53Prieur2004270Loïc Prieur2004Q
u
alité technologique et sanitaire des blés biologiques : premiers résultats d'une étude en Midi-PyrénéesAlter Agri664-9
T
aylor20012910B R TaylorC A WatsonE A StockdaleR G McKinlayD YounieS A A Cran
stoun2001Current practices and future prospects for organic cereal production : survey and literature reviewHGCA90ferbruary 2001}
}{\fldrslt {(Taylor et al., 2001)}}}{. Organic wheat production is also characte}{r}{ized by variable yields (from 1t/ha to 6,5 t/ha in a single region, }{\field\fldedit{\*\fldinst {
ADDIN EN.CITE David2004240<
AUTHORS>Christophe DavidPhilippe ViauxJean-Marc Meynard2004Les enjeux de la production de blé tendre biologique en FranceLe Courrier de l'E
nvironnement de l'INRA5143-53}}{\fldrslt {(David et al., 2004a)}}}{ and low and variable GPC (from 7 to 13 g per 1000 g). Mor}{e}{
over, the balance between offer and demand on organic wheat leads to a price d}{e}{cline : 255 \'80/t for organic milling wheat in 2005 against 365 \'80/t in 2002 (V}{i}{aux, personal communication). Cons}{e}{quently, millers often di}{s}{
qualify or discount batches when GPC is too low facing brea}{d}{making criteria.
\par }\pard \s18\qj \li0\ri0\sl220\slmult0\widctlpar\aspalpha\aspnum\faauto\adjustright\rin0\lin0\itap0 {It is now critical for organic farmers to incr
ease and stabilize grain yield and GPC throughout a better control of limiting factors affecting winter wheat production.
\par As grain yield and GPC are strongly linked to N availability in soil, assessment of adequate spring organic fertilisation is a real stake.
\par Optimal strategies of N fertilization can be derived from the Azodyn-Org model }{\field\fldedit{\*\fldinst {
ADDIN EN.CITE David200410Christophe DavidMarie-Hélène JeuffroySylvie RecousFruck Dorsainvil2004Adaptation and assessment of the Azodyn model for managing the nitrogen fertilization of organic winter wheatEuropean Journal of Agronomy21249-266}}{\fldrslt {(David et al., 2004b)}}}{
, as soon as the occurrence and effect of limiting factors on the field can be predicted (David et al., 2005). It is thus necessary to assess early indicators to fore
cast the occurrence of limiting factors and their effects on yield and GPC. The aim of this work is to understand and rank the limiting factors explaining both yield and GPC and then identify the characteristics of the cropping sy}{s}{
tems explaining these limiting factors. We will also generalize the results from the previous study conducted only on yield in the Sout}{h}{east of France }{\field\fldedit{\*\fldinst { ADDIN EN.CITE David200520Christophe DavidMarie-Hélène JeuffroyJohn HenningJean-Marc Meynard2005Yield va
riation in organic winter wheat : a diagnostic study in the Southeast of FranceAgronomy for Sustainable Development25213-223}}{\fldrslt {(David et al., 2005)
}}}{ by enlarging the stu}{d}{ied sites
\par }\pard \s18\qj \li0\ri0\sl220\slmult0\widctlpar\aspalpha\aspnum\faauto\widctlpar\aspalpha\aspnum\faauto\pnrauth1\pnrdate-2036155337\pnrnot1\adjustright\rin0\lin0\itap0 {
\par }\pard\plain \s19\qc \li0\ri0\sa40\sl220\slmult0\keepn\widctlpar\aspalpha\aspnum\faauto\outlinelevel0\adjustright\rin0\lin0\itap0 \scaps\f29\fs18\lang2057\langfe1030\cgrid\langnp2057\langfenp1030 {Materials and methods
\par }\pard\plain \s18\qj \li0\ri0\sl220\slmult0\widctlpar\aspalpha\aspnum\faauto\adjustright\rin0\lin0\itap0 \f29\fs16\lang2057\langfe1030\cgrid\langnp2057\langfenp1030 {This research is based on a multi-year and multi-site fields\rquote
network. The diagnosis method used }{\field\fldedit{\*\fldinst { ADDIN EN.CITE Doré199760
REFERENCE_TYPE>Thierry DoréMichel SebillotteJean-Marc Meynard1997A Diagnostic Method for Assessing Regional Variations in Crop YieldAgr
icultural Systems542169-188}}{\fldrslt {(Dor\'e9 et al., 1997)}}}{ is divided in two steps: (i) analyse the yield build-up from enviro}{n}{
ment and crop status on farmers\rquote fields and then (ii) identify the characteri}{s}{tics of cropping systems, climate and soil respons}{i}{ble for differences in environment and crop status.
\par }\pard \s18\qj \li0\ri0\sl220\slmult0\widctlpar\aspalpha\aspnum\faauto\widctlpar\aspalpha\aspnum\faauto\pnrauth1\pnrdate-2036155427\pnrnot1\adjustright\rin0\lin0\itap0 {
\par }\pard \s18\qj \li0\ri0\sl220\slmult0\widctlpar\aspalpha\aspnum\faauto\adjustright\rin0\lin0\itap0 {\i Experimental design
\par }{Three field network taken from previous studies were chosen, in order to provide a wide range of conditions involving various limiting factors : 52 fields during 4 crop years in Southeast of France }{\field\fldedit{\*\fldinst {
ADDIN EN.CITE David200520Christophe David
AUTHOR>Marie-Hélène JeuffroyJohn HenningJean-Marc Meynard2005Yield variation in organic winter wheat : a diagnostic study in the Southeast of FranceAgronomy for Sustainable Development25213-223}}{\fldrslt {(David et al., 2005)}}}{, 25 fields during 2 crop years in the Paris Basin }{\field\fldedit{\*\fldinst {
ADDIN EN.CITE Champeil<
Year>2004312Agnès Champeil2004Contribution à la compréhension des effets des systèmes de culture sur l'infection
des cultures de blé tendre d'hiver par la fusariose et la contamination des grains par les mycotoxines associéesINA P-G132PhD Thesis}
}{\fldrslt {(Champeil, 2004)}}}{ and four exper}{i}{ments on cultivars during 5 crop years }{\field\fldedit{\*\fldinst {
ADDIN EN.CITE Rolland2003337B. RollandA. BouguennecX. Charrier O. Gardet A. Faye M. Al RifaiJ.Y. MorlaisF.X. Oury2003Comportement en agriculture biologique d'une large
gamme de lignées récentes de blé tendre et de triticale. Premiers résultats de deux années d'expérimentation INRA et comparaisons avec des conduites faibles intrants et intensives.Actes du Sé
;
minaire INRA-CIABDraveil, France20-21 Nov 2003Rolland2003337B. Rolla
n
dA. BouguennecX. Charrier O. Gardet A. Faye M. Al RifaiJ.Y. MorlaisF.X. Oury2003Comportement en a
g
riculture biologique d'une large gamme de lignées récentes de blé tendre et de triticale. Premiers résultats de deux années d'expérimentation INRA et comparaisons avec des conduites faibles intrants et intensives.
TITLE>Actes du Séminaire INRA-CIABDraveil, France20-21 Nov 2003}{\deleted\revauthdel1\revdttmdel-2036155356
ADDIN EN.CITE Rolland200333
RecNum>3B. RollandA. BouguennecX. Charrier O. Gardet A. Faye M. Al RifaiJ.Y. MorlaisF.X. Oury2003Comportement en agriculture biologique d'une large gamme de lignées récentes de blé tendre et de triticale. Premiers résultats de deux années d'expérimentation I
NRA et comparaisons avec des conduites faibles intrants et intensives.Séminaire INRA-CIABDraveil, France20-21 Nov 2003}}{\fldrslt {
(Rolland et al., 2003)}}}{.
\par Moreover, a new farmers\rquote fields\rquote
network will be designed for the next two years (2005-2006 and 2006-2007) including circa 10 organic winter wheat fields per crop year within Southeast of France in order to cover a large range of environmental cond}{i}{
tions (particularly soil types and water availability) and cropping systems, leading }{\i a priori }{to various limiting factors (David et al, 2005). Cropping sy}{s}{tems are characterised by crop rotation, prev}{i}{
ous crop, soil tillage, sowing date and density, N fertil}{i}{zation (type of fertilizer, date, amount), weeding and irrigation (date, amount). Some fields will i}{n}{
clude an irrigated treatment to avoid water stress. Moreover variation in weed pressure and N fertiliz}{a}{tion will be included within some fields, by applying various fertilization strategies or controlled trea}{t}{
ments with (no weeding) or without (by hand wee}{d}{ing) weeds. Thus several trea}{t}{ments will be provided in some fields, varying in water availability, N avai}{l}{ability and weed pressure.
\par
\par }{\i Measurements
\par }{The physical and chemical composition of soil samples (10 per field) will be measured (texture, N, P, K and organic matter content). Daily weather data (minimum and maximum temperature, rainfall, radiation and evapotra}{n}{spiration) will be recorded.
\par At the end of winter, an homogeneous zone (with regard to soil type, wheat density and stage and weed population) will be determined per field. Within this area, 7 sample plots (0,25 m\'b2
) per treatment will be collected at harvest to measure grain yield, thousand kernel weight, kernel number and GPC.
\par Several indicators of limiting factors will be mea}{s}{ured. Water stress will be estimated from a dynamic water balance. High te}{m}{peratures will be calculated. Weed pressure will be characte}{r}{ized at different stages through se
veral variables : density, cover rate, Leaf Area Index, height ratio with wheat, aboveground biomass and N content of weeds and wheat height, biomass and N content at different stages. Aerial foliar diseases will be assessed on the upper two leaves of whe
at after flowering, soil di}{s}{eases will be assessed at stem elongation and lod}{g}{ing will be assessed at harvest. In each field, a soil profile pit will be examined after flowering in order to determine the soil compaction{\*\bkmkstart OLE_LINK1}.
\par Farmers cropping systems and farmers techniques will be recorded by interviews.
\par
\par }{\i Statistical analysis
\par }{The identification of limiting factors and the quantif}{i}{cation of their effect on yield and GPC will be co}{n}{ducted using quantile regre}{s}{sion }{\field\fldedit{\*\fldinst {\revised\revauth1\revdttm-2036155496 }{ADDIN}{
\revised\revauth1\revdttm-2036155496 EN.CITE Cade2003120Brian S. CadeBarry R. Noon2003A gentle introduction to quantile regression for ecologistsFrontiers in Ecology and the Environment18412-420}{\deleted\revauthdel1\revdttmdel-2036155496
ADDIN EN.CITE Cade2003120<
/REFERENCE_TYPE>Brian S. CadeBarry R. Noon2003A gentle introduction to quantile regression for ecologistsFront Ecol Environ18412-420}}{\fldrslt {(Cade and Noon, 2003)}}}{.
\par {\*\bkmkend OLE_LINK1}
\par }\pard\plain \s19\qc \li0\ri0\sa40\sl220\slmult0\keepn\widctlpar\aspalpha\aspnum\faauto\outlinelevel0\adjustright\rin0\lin0\itap0 \scaps\f29\fs18\lang2057\langfe1030\cgrid\langnp2057\langfenp1030 {Results and expected results
\par }\pard\plain \s18\qj \li0\ri0\sl220\slmult0\widctlpar\aspalpha\aspnum\faauto\adjustright\rin0\lin0\itap0 \f29\fs16\lang2057\langfe1030\cgrid\langnp2057\langfenp1030 {The effects of environment and cropping syste}{m}{
on the yield-build up and GPC will be an}{a}{lysed in four stages : (i) identifying the yield and quality comp}{o}{nents that best explained vari}{a}{tions in output, (ii) identifying the enviro}{n}{
mental conditions of the fields (iii) analysing the relationships between indicators of possible limiting factors and yield components and (iv) determining the rel}{a}{tionships between cropping system chara}{c}{
teristics and measured yield-limiting factors.
\par In a previous study }{\field\fldedit{\*\fldinst { ADDIN EN.CITE David200520Chri
stophe DavidMarie-Hélène JeuffroyJohn HenningJean-Marc Meynard2005Yield variation in organic winter wheat : a diagnostic study in the Southeast of France
TITLE>Agronomy for Sustainable Development25213-223}}{\fldrslt {(David et al., 2005)}}}{ o}{b}{served that the heat temperature during grain filling limi}{t}{
ing thousand grain weight. However, the lack of diversity within the field network considering water rainfall and stress did not allow to evaluate the e}{f}{fect of water balance on wheat pe}{r}{
formance. They also demonstrated that N nutrition and weeds mainly limited the kernel number/m\'b2 when soil compaction limited kernel weight. The diagnosis also highlighted that sowing date, crop rotation and pr}{e}{vious crop mainly dete}{r}{
mined the level of the N nutrition and weeds.
\par With the new designed fields\rquote network i}{n}{cluding various treatments we expect a large range of env}{i}{ronmental conditions and cro}{p}{ping systems : mixed farms producing c}{e}{
reals and fodder legumes with organic manure, more intensive mixed farms pr}{o}{ducing cereals, grain le}{g}{umes and/or hoed crops with organic N fertilizer and e}{x}{tensive mixed or arable farms with poor fertilization. With this inclu}{d}{
ing various treatments we want to explain the GPC variabi}{l}{ity by the limiting. We also expect that the new network associated with previous dat}{a}{bases will help to precise the ranking of the limiti
ng factors especially and to identify some expected limiting fa}{c}{tors such as water stress.
\par }\pard \s18\qj \li0\ri0\sl220\slmult0\widctlpar\aspalpha\aspnum\faauto\widctlpar\aspalpha\aspnum\faauto\pnrauth1\pnrdate-2036155392\pnrnot1\adjustright\rin0\lin0\itap0 {
The characteristics of the cropping systems involved in the limiting factors will be determined, thus allo}{w}{ing us to imagine some recomme}{n}{dations to the farmers in order to reduce their yield and GPC var}{i}{ability and improve their performance.
\par }\pard \s18\qj \li0\ri0\sl220\slmult0\widctlpar\aspalpha\aspnum\faauto\adjustright\rin0\lin0\itap0 {
\par }\pard\plain \s19\qc \li0\ri0\sa40\sl220\slmult0\keepn\widctlpar\aspalpha\aspnum\faauto\outlinelevel0\adjustright\rin0\lin0\itap0 \scaps\f29\fs18\lang2057\langfe1030\cgrid\langnp2057\langfenp1030 {Conclusion
\par }\pard\plain \s18\qj \li0\ri0\sl220\slmult0\widctlpar\aspalpha\aspnum\faauto\adjustright\rin0\lin0\itap0 \f29\fs16\lang2057\langfe1030\cgrid\langnp2057\langfenp1030 {This work will provide results on the effects of limi}{t}{
ing factors on yield and GPC by using the diagnostic method. Then it will be necessary to find some early indica
tors of these limiting factors in order to use them to determine adequate fertilization or weeding strategies. One of the issue of this work is to build a tool used by farmers that allow to apply optimal fertilization strategies by observing early and acc
e}{s}{sible indic}{a}{tors on field.
\par
\par }\pard\plain \s19\qc \li0\ri0\sa40\sl220\slmult0\keepn\widctlpar\aspalpha\aspnum\faauto\outlinelevel0\adjustright\rin0\lin0\itap0 \scaps\f29\fs18\lang2057\langfe1030\cgrid\langnp2057\langfenp1030 {References
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\par }\pard \s18\qj \fi-720\li720\ri0\sl240\slmult0\widctlpar\aspalpha\aspnum\faauto\adjustright\rin0\lin720\itap0 {
\par }}