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Is it possible to improve the yield and grain protein concentration of organically-farmed wheat using cover crops or intercrops?

JUSTES, J. ; BEDOUSSAC, L. and PRIEUR, L. (2009) Is it possible to improve the yield and grain protein concentration of organically-farmed wheat using cover crops or intercrops? [Est-il possible d’améliorer le rendement et la teneur en protéines du blé en Agriculture Biologique au moyen de cultures intermédiaires ou de cultures associées ?] Carrefours de l'Innovation Agronomique, 4, pp. 165-176.

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Online at: http://www.inra.fr/ciag/revue_innovations_agronomiques/volume_4_janvier_2009

Summary

The objective of our work was to investigate innovative sustainable cropping systems to produce regular yields of wheat with a satisfactory grain protein concentration in organic farming systems. Achieving good production levels in stockless French organic farming systems is a major challenge due to strong N limitation. Our approach is mainly based on a better valorisation of the natural nitrogen resources from soil mineralisation and symbiotic fixation of legumes, and not by an increase in the use of organic fertiliser. Two experiments were carried out in southwestern France where winter wheat and durum wheat were grown for their use in human consumption (bread and pasta, respectively). On one hand, cover crops were sown in summer and were incorporated in early November just before the wheat was sown. On the other hand, wheat was cultivated in mixture (intercropping) with a grain legume such as winter pea or fababean. The cover crops were found to be effective in the case of rainy winter years i) because of their role as a nitrate catch crop to mitigate nitrate leaching and ii) because they made it possible to increase the yield and the protein concentration of wheat grains by increasing available N (role of green manure). In the case of intercropping, wheat yield was reduced in comparison to a wheat crop alone, as expected, but the protein concentration was significantly increased and the whole grain yield (wheat + legume) was increased. Thus, in organic farming, intercrops seem to be more effective for enhancing natural nitrogen resources. However, it is still necessary: (i) to optimise the technical sequences of these two farming systems, and; ii) to determine the role of intercrops within rotations and to analyse their effect for both pests and diseases management, which is crucial in organic farming systems.

Summary translation

L’objectif du travail est de trouver des systèmes de culture durables pour produire en AB des rendements de blé réguliers et de bon niveau avec une teneur en protéines satisfaisante. Notre démarche repose sur une valorisation optimale des ressources naturelles en azote provenant de la minéralisation du sol et de la fixation symbiotique. D’une part, des cultures intermédiaires ont été semées en été et enfouies avant le semis du blé réalisé en novembre afin de limiter les pertes hivernales d’azote nitrique. D’autre part, le blé a été cultivé en association avec une légumineuse à graines (pois ou fèverole d’hiver). Les cultures intermédiaires sont efficaces dans leur rôle de piège à nitrate et permettent d‘augmenter le rendement et la teneur en protéines du blé lors des années pluvieuses. En culture associée, le rendement du blé est réduit mais la teneur en protéines est significativement augmentée et le rendement total (blé+légumineuse) est plus élevé. Ainsi, en AB, les cultures associées sont plus efficaces pour utiliser les ressources naturelles en azote. Il reste cependant i) à optimiser les itinéraires techniques de ces systèmes de culture, et, ii) déterminer la place des associations au sein des rotations et analyser leur effet pour la gestion des bioagresseurs.

EPrint Type:Journal paper
Keywords:nitrogen; cover crop; intercrop; winter wheat; durum wheat; grain protein concentration.
Subjects: Crop husbandry > Production systems > Cereals, pulses and oilseeds
Crop husbandry > Crop combinations and interactions
Crop husbandry > Composting and manuring
Research affiliation: France > INRA - Institut National de la Recherche Agronomique
Related Links:http://www1.montpellier.inra.fr/dinabio/
Deposited By: PENVERN, Servane
ID Code:15483
Deposited On:02 Mar 2009
Last Modified:12 Apr 2010 07:39
Document Language:French - Francais
Status:Published
Refereed:Peer-reviewed and accepted

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