Search

Soybean is prone to weed infestation and yield variability. With the proposition of using intercropping to overcome these problems, this study explored the effects of combinations of different associated crop species andspatial arrangements on grain production and weed control.In a two-year field experiment in western France, soybean was intercropped with buckwheat, lentil, sorghum and sunflower in two spatial arrangements, within-row intercropping and alternate-rowintercropping, to investigate their effects on weed control and soybean production.The results showed that the highest soybean yieldoccurred in the intercropping with lentil,followed by sorghum and sunflower, and finally buckwheat, but this effect varied by year. The opposite species order was obtained for the weed control service, revealing a trade-off between the soybeanproduction and weed control. We also demonstrated that associated species height was related to soybean yield and weedcontrol. Alternate-row intercropping helped to increase soybean production without compromising weed control for sorghum and buckwheat, which have small height difference with soybean. Finally, our paper showed that combining associated species choice and spatial arrangement allows farmers to manage the trade-off between soybean yield and weed control.

La diversification (allongement des rotations, introduction de cultures intermédiaires, cultures relais, associations…) est un des leviers majeurs pour une transition agroécologique des systèmes de culture. Cependant, toute diversification n’est pas bonne en soi car ses performances dépendent des cultures introduites et de la manière de les assembler. Pour aider les acteurs à orienter leur choix de configuration des systèmes de culture, nous avons développé un indicateur de diversité globale des cultures de la rotation (I-DGC) basé sur une construction en arbre hiérarchique. Celui-ci comprend une évaluation des diversités temporelle et spatiale. La diversité temporelle est ensuite décomposée en un indicateur de diversité taxonomique et un de diversité fonctionnelle, celle-ci étant liée à la fourniture de douze services écosystémiques (SE). L’indicateur global calculé à partir des données sur les cultures permet d’estimer a priori, l’effet potentiel de la diversification d’une rotation. L’estimation des douze SE sur un ensemble de rotations typiques des agroécosystèmes montre des variations importantes. Par ailleurs, l’allongement de la rotation et l’augmentation du nombre de cultures ne sont pas suffisants ; ils doivent être associés à un choix adéquat des cultures et de leur succession. Mots clés : transition agroécologique, diversification, diversité spatio-temporelle, succession cultures, association de culture, cultures en bandes

There is a need to re-diversify current cropping systems in Europe to improve their sustainability and their resilience. A network of field experiments was built to study the benefits of crop diversification in time and space in organic systems in five countries in Europe. Different strategies of crop diversification are combined at the rotation scale. The insertion of spatial diversification (cereal-grain legume intercropping, strip cropping both in arable and vegetable systems) in a cropping system should be encouraged owing to positive effects on yield and ecosystem services, based on the first results obtained in the network.

There is a lack of results on the advantages and limitations of combining different crop diversification strategies both in time and space, which makes it difficult for famers and advisers to find relevant information for the transition towards more diversified cropping systems. A network of ten field experiments (diverIMPACTS project) was built across seven European countries, covering a range of pedo-climatic conditions and different farming systems: arable and vegetable systems under both conventional and organic management. Each field experiment tests one or several diversified cropping systems, which combine three diversification strategies with low input practices. These diversified cropping systems are compared to reference systems, which are less diversified and more dependent on external inputs. The three strategies of crop diversification are rotation, multiple cropping (growing different crop species on the same land within one growing season) and intercropping (growing different species in proximity on the same field). A diversified system includes, for example, the addition of cover crops or cash crops, such as legumes, for their expected ecosystem services, or crops for new markets (e.g hemp, lentil), the use of multiple cropping to increase productivity per year (e.g. winter barley with soybean) and intercropping (e.g. barley/pea,wheat/faba bean, oat/lupin) to increase productivity per unit of area and reduce external inputs. Expected impacts include: higher arable land productivity, diversification and increased farmer revenues through access to new markets and reduced economic risk, lower environmental impact through reduced use of pesticides, chemical fertilisers, energy and water, and improved delivery of ecosystem services, including biodiversity. The diversified cropping systems will be assessed using standardized measurements across the network and multi-criteria assessment tools. Decisions regarding the design and management of the diversified cropping systems will be recorded to support other diversification initiatives. The year 2018 is the first year of the network. This paper presents the original approach, the strategies designed in the network, and the assumptions concerning the interests to combine temporal and spatial diversification in order to improve the delivery of multiple services. This network will be a source of inspiration for other initiatives of crop diversification in Europe. The ultimate goal is to guide farmers in their transition towards more diversified cropping systems and to promote innovations by various actors at different scales (e.g. innovations regarding machinery for sowing or harvesting new sole or mixed crops, value-chains through the consolidation of new markets, new process of transformation, or adaptation of value-chains to intercropping).

International audience; Legumes offer a wide array of services to be promoted in production systems and supply chains: production of protein-rich raw materials with interesting nutritional properties for both food and feed; beneficial preceding crop effects through the restitution of biologically fixed N and the time/space diversification of cropping systems. However the high variability of performances hinders anticipating and exploiting such services through adapted cropping system management. Today, stakeholders are lacking local references for diverse legume species and insertion modes (sole crops, intercrops for cash crops as well as cover crops). Hence approaches to insert more legumes in territories need to be assisted by identifying 1) the actor’s expectations, 2) services obtained by farmers in real farm context, 3) the main variability factors and levers to optimally exploit services, and by sharing results with actors. In 3 french territories (Pays de la Loire-PDL, Burgundy-B and Midi-Pyrénées-MP) observatories have been set up in partnership with cooperatives. Several species and insertion modes selected by local actors have been studied: spring/winter lupin as sole crop or intercropped with triticale (PDL); alfalfa and spring pea (B), soybean, and lentil as sole crop or intercropped with wheat (MP). A 2-year followup of the legume crop and the next crop has been performed in 2015-16 and was repeated on other plots in 2016-17. The variability of productivity (grain and protein yield) and grain protein content was high but differed according to species. Moreover there is a high variability in the yields and N acquisition of the following crops in relation to the performances of the legume and its N acquisition and allocation (N2 fixation, nitrogen harvest index, nitrogen in residues). The conditions and levers required to achieve both high yield productivity of legumes and high N preceding effect are discussed.

The organic bread wheat market has been diversified over time through the emergence of different sale channels. Processors require organic bread wheat of higher quality and safety in order to meet the consumers’ demand. The overall objective of the AGTEC-Org project was to identify agronomical and technological ways to improve the performance of organic wheat and flour. The findings would contribute to enhanced baking quality and nutritional value of organic flour, as well as prevention of mycotoxin contamination. The project involved 9 research centers or universities from 5 European countries for a total budget of about 1.5 million €. More than 400 experimental treatments were analyzed from 23 agronomic trials and 4 lab-experiments on food technology. Choice of cultivar is an efficient way to obtain higher grain quality. Intercropping legumes (grain or forage) improves weed control and N availability for wheat crop or succeeding crop. Green manure can be an effective alternative to farmyard manure. Fertilization with organic fertilizers improves yield and quality when water is available. Reduced tillage affects soil fertility and wheat yield but has little effects on grain quality. Milling process strongly influences flour characteristics. Stone milling improves the nutritive value and flour characteristics remain very stable independently of the milling yield. However, stone milling slightly raises DON levels. Characteristics of flour produced by means of roller milling appear very dependent on milling yield, instead. Increasing milling yield with the aim of enriching nutritional quality has a detrimental effect on either safety (DON) or bread-making quality (bread volume). Debranning before milling has a very positive impact on flour safety by reducing its DON content by 50 %.

absent

Organically farmed pea, lupin and faba bean were compared in terms of dry matter (DM), grain yield and nitrogen (N) production, as well as for their competitive ability against weeds. Adjacent strips of pea, lupin and faba bean were set up at eight sites throughout the Pays de la Loire region. Soil conditions and weed pressure differed between sites. In general, faba bean produced slightly more grain yield and grain N than pea. Lupin was the least productive grain legume and the weakest competitor against weeds, though it provided grains with the highest N contents. However in most situations, pea was shown to be the most efficient until flowering for DM and N accumulation as well as for light interception and crop height. A faster development of aboveground plant parts at early growth stages and a better soil N uptake were likely explanations for the lowest weed DM of pea. However DM of pea, lupin and faba bean were equally limited by weeds despite the differences in weed biomass between these species.