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ANANABIO est un projet multipartenarial mené de 2016 à 2018, dont l’objectif est de proposer despratiques innovantes compatibles avec le cahier des charges français pour l’agriculture biologique etissues de collaborations avec les producteurs, et une auto-évaluation de leurs systèmes de cultureintégrant ces innovations. Une carte d’évaluation des systèmes de culture a été réalisée. Elle intègre 45variables dans les domaines agro-envionnemental, économique et social. Le projet a proposé dessolutions de fertilisation incluant des farines plume et sang et la biomasse de plantes de service (jusqu’à15 t MS/ha), notamment des espèces de crotalaires utilisées également pour la gestion des adventiceset des parasites racinaires (plantes dont le statut d’hôte de R. reniformis et des symphyles a été vérifié).Un itinéraire technique de pépinières réalisées à partir de vitroplants pour la production de matérielvégétal sain a été proposé pour une meilleure gestion du Wilt de l’ananas par réduction des populationsde cochenilles D. brevipes associés aux virus du Wilt (jusqu’à 20 plants récoltés/vitroplant planté). Deséquipements ont été testés pour broyer finement les vieux plants très contaminés. Cette pratique aide àassainir les parcelles en limitant le développement des inocula parasitaires. Un équipement d’aide à laplantation a été co-conçu et réalisé par les producteurs avec l’appui de L’Atelier Paysan. Au final, lessystèmes de culture bio élaborés devront respecter le concept d’agroécologie pour la promotion d’uneagriculture qui respecte l’homme dans son environnement.; ANANABIO is a multi-partnership project (2016-2018) in Reunion to design innovative practicesfollowing the French specifications for organic production through a collaboration with the producers,and a self-evaluation of their cropping systems integrating some of the innovations. An evaluation formof the cropping systems was designed. It integrated 45 variables in the agro-environmental, economic and social fields. The project proposed fertilizing solutions including feather and blood meal mixed withthe biomass of cover crops (up to 15t DM/ha), in particular species of rattlesnakes (Sunn hemp orothers) used also for the management of weeds and root parasites control (plants whose host status fornematodes and symphylids has been verified). A technical itinerary for nurseries made from in vitroplantlets to produce healthy planting material has been proposed for better management of pineapplewilt by reducing populations of D. brevipes mealybugs associated to Wilt viruses (up to 20 plantsproduced / tissue culture plant planted). Equipments to shred finely old contaminated plants wereevaluated, as this cultural practice helps cleaning up the plots by limiting the development of parasiteinocula. Planting assistance equipment was co-designed and made by the producers with the support of"L’Atelier Paysan". Overall, the organic cropping systems elaborated must respect the concept ofagroecology for the promotion of an agriculture that respects humans in their environment.

Cover plants have a high potential to manage weeds through competition for shared resources in tropical agrosystems. Assessing the abilities of a large number of different plant species to compete with weeds requires long-term experiments in different pedoclimatic environments. Our study was based on a set of 10 trials including 46 species of cover plants and performed from 2016 to 2018 in three sites in Reunion. Our aim was to identify and measure plant traits that optimize plant coverage and weed control by cover plants under tropical climate. We characterized two traits of interest (a soil coverage efficiency index and a coverage growth rate) using a hierarchical clustering analysis and compared them between plant area of origin, life cycle or growth habit. The ability for cover plant to cover efficiently and rapidly the soil increased with growth rate in height and leaf appearance rate while tends to decrease with thermal time for emergence. Accordingly, weed control efficiency (low weed coverage and dry mass) was strongly correlated and increasing with cover plant growth rate in coverage, height and biomass. The characterization of plant species using functional traits enabled to identify cover plants which could be used in tropical agrosystems as an alternative to herbicides. Assuming that the spatial and temporal combinations with the main crop will determine the performances of the system, we discussed a trait-based methodology to identify the cover plants adapted to sugarcane agrosystems in Reunion.

Cover plants have a high potential to manage weeds through competition for shared resources in tropical agrosystems. Assessing the abilities of a large number of different plant species to compete with weeds requires long-term experiments in different pedoclimatic environments. Our study was based on a set of 10 trials including 46 species of cover plants and performed from 2016 to 2018 in three sites in Reunion. Our aim was to identify and measure plant traits that optimize plant coverage and weed control by cover plants under tropical climate. We characterized two traits of interest (a soil coverage efficiency index and a coverage growth rate) using a hierarchical clustering analysis and compared them between plant area of origin, life cycle or growth habit. The ability for cover plant to cover efficiently and rapidly the soil increased with growth rate in height and leaf appearance rate while tends to decrease with thermal time for emergence. Accordingly, weed control efficiency (low weed coverage and dry mass) was strongly correlated and increasing with cover plant growth rate in coverage, height and biomass. The characterization of plant species using functional traits enabled to identify cover plants which could be used in tropical agrosystems as an alternative to herbicides. Assuming that the spatial and temporal combinations with the main crop will determine the performances of the system, we discussed a trait-based methodology to identify the cover plants adapted to sugarcane agrosystems in Reunion.

In order to increase the area of sugarcane production, planting techniques should ensure uniform crop emergence and control of weeds at reasonable cost. Experiments using single- bud setts have been conducted in several countries (Brazil, India, Indonesia, and Egypt). In this poster, we present the advantages of planting germinated single-bud setts grown in pots into a cover crop with the aim of reducing soil tillage and herbicide usage in an agro- ecological approach to sugarcane production. Two trials were carried out to assess the effectiveness of germinated single-bud setts compared with traditional planting of three-bud setts. This included i) the quantity of planting material, yield and components thereof, and ii) the use of herbicide. In the first trial, the weights and number of tillers per plant were measured at 11 months after planting. In the second trial, germinated single-bud setts were planted into plant cover originating from a succession of a planted mixture of Crotaleria juncea and Mucuna, and Avena sativa. Tillering, stalk elongation and yields (plant and ratoon) were compared with those of traditionally planted cane in single rows. Time and herbicide inputs were quantified. In the first trial, both yields and number of nodes per stalk were similar for the germinated single-bud setts and the traditionally planted cane, but the number of stalks was significantly higher (8%) for the germinated single-bud setts. The average multiplication rate of the single- bud setts was 1:99 at 11 months. In the second trial, the number of tillers was again 8 % higher for the single-bud setts. There was no significant differences in stalk elongation and yields. In ratoon cane, no significant differences were observed. From an economic point of view, a saving of more than 80% of buds was achieved at planting. However, the increased labor requirement generated additional costs. Planting germinated single-bud setts into mulch resulted in reduced herbicide applications and erosion risks. Our study highlighted planting of germinated single-bud setts (in pots) into mulch as a reliable and affordable technique. In terms of the planting operation and yields, it is comparable with conventional planting techniques and can reduce soil tillage and the use of herbicides. Theoretically this technique reduces the risk of erosion while favoring water retention and increased functional biodiversity. It gives the advantage of complete and homogeneous emergence, as well as the possibility of bringing complementary nutrients in the pot near to the roots. Nevertheless, for Reunion Island conditions, progress still needs to be made in terms of acclimatization and mechanical transplantation of young plants.

Cover crops are increasingly being used for weed management in tropical regions as an alternative to herbicides. However, selecting the most suitable cover crop to be associated with a main crop requires long-term investigation. Here we present details of a set of trials conducted over two years to assess the ability of various cover crops to limit weed growth in sugarcane agrosystems. Firstly, 55 species/varieties were assessed in terms of their growth cycle and viability at three different locations in tropical conditions on Reunion Island. This trial allowed selection of cover crop species that would be suitable for either rotational cropping or intercropping with sugarcane. Secondly, 10 species were selected and grown in large plots in four different trials. This allowed for assessment of their ability to limit weed growth in monospecific plots and where mixtures of cover crops were grown. After two months of growth, the most productive cover crops showed the ability to limit weed growth to fewer than 30% of the plot (e.g. crotalaria, oat and millet). The less productive cover crops were unsuccessful in limiting weeds. In comparison, all combinations of two cover crops tested in this experiment were able to limit weed growth to fewer than 30% of the plot area. These trials highlight some key cover crops that are suitable for intercropping and rotations in sugarcane agrosystems as alternative to herbicides.

La connaissance des différentes unités agronomiques au niveau d'un terroir et leur utilisation par les agriculteurs est indispensable si l'on veut adapter les propositions de systèmes SCV aux contraintes du milieu. Ces unités agronomiques sont définies de manière à constituer des ensembles homogènes, pour lesquels les systèmes de cultures que l'ont peut proposer sont identiques. Ainsi, l'origine d'un sol n'est pas vraiment discriminante (il ne s'agit pas d'unités pédologiques), mais on s'attache avant tout à prendre en compte les caractères discriminant les possibilités de culture. Dans la zone agro-écologique de moyenne altitude, avec longue saison sèche, la différenciation agronomique des sols se fait sur la base de leur niveau de fertilité, de leur compaction, et de leur régime hydrique (en saison et en contre-saison). Ainsi, les pratiques agronomiques peuvent faire évoluer une parcelle d'une unité à une autre. Par exemple, un sol compacté sur lequel on installe des plantes de couvertures au système racinaire très puissant, peut ainsi évoluer en quelques années vers un sol non compacté. De même, la fertilité du sol peut évoluer, dans un sens ou dans un autre. En pratique, on peut distinguer ces unités en se basant sur la couleur du sol, la flore en place et les performances des cultures conduites par les paysans.

Présentation de l'éditeur : Agriculture in whatever age, under whatever natural, economic and social conditions, has to feed the human being. To fulfil this mission, the sector has to overcome continuous and changing challenges to achieve notable developments. The Green Revolution, through developing and introducing high-yielding crop varieties and advanced crop management techniques, saved billions people from starvation. The advent of biotechnology, in its turn, has speed up the agricultural growth to meet food demands of the world's booming population. Continuous demographic pressure and rapid market integration have created necessity to further agricultural developments to meet not only food security, but also the increased demands for nutrition security, food safety, energy, etc., while the global climate change has created needs for capturing synergies between agricultural production and environmental protection. New breakthroughs to trigger the second Green Revolution have therefore become necessary. Thus, it is now the right time for us to consider the means to make "the Double-Green Revolution" to become a reality. Conservation Agriculture (CA) has demonstrated potential to meet this goal through designing and promoting the adoption of environment-sound and climate-resilient agricultural production systems. Increasing interests and efforts have been given to CA research for development in the Southeast Asia during the last 15 years. As a result, a new stage has been reached with the formation of the Conservation Agriculture Network for Southeast Asia (CANSEA) in 2009, in which efforts have been maintained to adapt concepts of CA to small scale farmers dealing with a great diversity of climate, land, topography and economy conditions. Enormous inputs are needed for the Southeast Asia to design specific and diverse CA innovations appropriate for local farmers and to promote their large scale adoption. This requires involvement of a wide range of stakeholders from both private and public sectors. This is the reason for us to gather together at the 3rd International Conference on Conservation Agriculture in Southeast Asia. At this conference, the results of a tremendous amount of creative work dedicated to CA development worldwide will be presented. The methods and tools for designing relevant CA innovations and the experience and proposals for their adoption will be shared. This volume compiles a picture portfolio of abstracts selected through a peerreview process for oral and poster presentations at the conference. Main topics addressed in this volume include (1) Agrarian transitions in the Southeast Asian uplands and highlands; (2) Impacts of agricultural systems on agricultural ecosystem sustainability; (3) Farming and cropping system design to sustainably intensify production; (4) Synergizing concepts of CA and Agroforestry; (5) Potentials and constraints of CA for rural development, and (6) Conditions, strategies, barriers and opportunities for scaling-up CA. This compilation represents a state and the art of CA research for development worldwide and the possible applications for the Southeast Asia

Les pratiques agricoles modifient les propriétés physiques et chimiques des sols, qui à leur tour peuvent affecter les micro-organismes qui y vivent avec des conséquences sur le fonctionnement biologique et la qualité de ces sols. Nous connaissons cependant peu de choses sur les interactions entre les pratiques agricoles, les propriétés physico-chimiques et les communautés microbiennes des sols. Peu d'études ont notamment été conduites dans les savanes herbacées des zones tropicales, fortement acides et lessivées, alors que ces espaces représentent des réservoirs importants de terres agricoles, aujourd’hui peu mis en valeur, alors qu’ils pourraient répondre, dans de bonnes conditions d’exploitation, au besoin local et régional d’augmentation et de pérennisation de la production agricole. Dans cette étude, nous nous sommes intéressés à l’impact de pratiques culturales (avec ou sans labour) sur les propriétés physiques, chimiques et microbiennes des sols d’une savane herbacée acide du nord-est laotien. Une rotation triennale riz/ maïs/ soja a été initiée en 2008, conduite selon 4 modalités culturales : 3 systèmes « zéro-labour » de semis direct sur couverture végétale (SCV) se différenciant par les plantes de couvertures associées avant et avec les cultures principales, et un système conventionnel (CONV) basé sur un labour annuel. L’impact de ces pratiques a été évalué deux ans après la conversion de ces terrains en terre agricole, en référence au pâturage naturel environnant (PAS). Malgré un nombre limité d’années de culture, nos résultats montrent un effet rapide des pratiques sur les caractéristiques des sols : contrairement à CONV, les SCV s améliorent les caractéristiques physico-chimiques des sols (stabilité structurale, matières organiques des sols et capacité d’échange cationique) ainsi que l'abondance microbienne (biomasse totale, densités bactérienne et fongique). Nous avons également observé des différences significatives de structure génétique des communautés bactériennes du sol entre SCVs, CONV, et PAS. De façon intéressante, l'abondance et la diversité bactérienne sont apparues différemment influencées par les changements d'environnement du sol: alors que la densité bactérienne a été affectée par la quantité et la diversité des résidus de récolte restitués au sol, à la teneur en carbone organique du sol et à la somme des bases échangeables du sol, la structure génétique bactérienne de sol a, de son coté, été principalement déterminée par la teneur en aluminium, le pH, la capacité d'échange cationique et le rapport C /N du sol. Cette étude, qui représente l’une des évaluations environnementales de pratiques agricoles les plus complètes en milieu tropical acide, nous amène à recommander les systèmes de semis direct sans labour avec restitutions élevées en résidus de récolte afin d'améliorer les propriétés physiques, chimiques et microbiennes des sols acides tropicaux et de contribuer ainsi à la durabilité de l'agriculture dans ces écosystèmes.

In the four southern districts (Kenthao, Paklay, Boten, and Thongmixay) of Xayabury province, the current cropping systems are based on cash crop production. Maize is the main crop under rainfed conditions and covers more than 30,000 ha in the region. Land preparation is based mainly on plowing, which degrades soil and destroys infrastructures (paddy fields and roads). These deteriorations result from growing pressure on agricultural systems and farmers' lack of access to affordable labour. This study sought to analyze soil aggregation, soil water-holding capacity, and soil biological activity under tillage and notillage conditions in relation to the cropping sequence. Three cropping sequences were investigated: 1. maize monoculture; 2. two-year rotational sequence, maize - rice bean; 3. two-year rotational sequence, maize + Brachiaria ruziziensis - rice bean.). Each year of the sequence was represented under no-till (NT) and tillage (CT) practices. Independent of depth, soil aggregation was greater under no-till conditions and enhanced by crop rotation and higher dry matter production (maize + B. ruziziensis / rice bean). Soil macrofauna, that is, the number of species and amount of biomass, was increased with no-till and the cropping sequence. Earthworms increased with no-till and for some cropping sequences amounted to more than 50% of the total macrofauna biomass. The cropping sequences produced a limited amount of dry matter. The main challenge was to increase biomass productivity (above-ground and below-ground) to recover ecosystem functions (recycling of nutrients, carbon sequestration, high biological activity, integrated weed and pest management, etc.) in a medium-term process (five years). Generating and adapting intensive cropping sequences (high production of aboveground and belowground biomass combined with a high diversity) under no-tillage systems with smallholders is an essential step in achieving long-term land sustainability, to obtain more reliable harvests and higher farm profits.

The National Agroecology Programme (PRONAE) and the Southern Xayabury Application Point (PASS) of the Capitalization and Rural Development Support Programme (PCADR) have developed an approach in the provinces of Xayabury and Xieng Khouang that relies on direct sowing mulch-based cropping systems (DMC). This approach has provided relevant alternatives to traditional agricultural practices which can no longer ensure the foundations of sustainable agriculture. In view of the results obtained, be they socio-economic or environmental, the Council of Ministers asked the Ministry of Agriculture and Forestry (MAF) to promote these techniques throughout the country, and called for this approach to be included in university and school courses. It is in that context that the Sector-based Agroecology Programme (PROSA), whose main aim is to define and implement a national strategy for the dissemination of Conservation Agriculture based on agroecological techniques (DMC), operates. This strategy is based on implementing an Agroecology Action Plan relying on the necessary incorporation of natural capital in rural development policies. The plan involves programming activities, setting in place decision-making and operational processes and bringing into play financial, material and human resources on both a central and local level (province, district and sub-district). The finest level of intervention comprises groups of farmers linked to service centres set up by the government within the districts (Kum Ban Pattana). On each level, the agroecology action plan is to arise from an integrated and concerted approach, in which each category of rural development stakeholders is committed to a process in which their needs and skills are acknowledged by all. Likewise, on each level, it is necessary to define, in a concerted manner, the initiatives that have to be taken (diagnosis, planning, implementation, monitoring-appraisal), the tools required (training of the different stakeholders, organization and structuring of the State sector and of the private sector, contractualization between stakeholders) and the fields of involvement (extension, local development funding arrangements, management of natural resources, equipment management, organization of supply and marketing chains, etc.). Each of the two pilot provinces, Xayabury and Xieng Khouang, is in the process of defining its Provincial Action Plan in Agroecology. An initial diagnosis of farming systems and their envi ronmental impacts, along with the needs and contributions of each category of stakeholders, has been completed. The provinces then gave priority to defining decision making and operational processes, and setting in place financial arrangements for the Provincial Action Plans. Initially, two funding tools are under consideration: constitution of a development fund, and agricultural credit. On a central level, the decision-making and operational processes are directly attached to the Ministry of Agriculture and Forestry, notably via the Planning Department. The creation of a Research and Service Provider Centre in support of local and national development is envisaged. Likewise, on a central level, it is a matter of facilitating the implementation of training plans for the different stakeholders. Lastly, the inclusion of agroecology in university and school courses is under way. Also for the educational sector, it is necessary to define a training plan to strengthen the skills and abilities of teachers. The creation of a national, or even regional network associating agricultural faculties and agricultural schools would enable an economy of scale by more effectively taking advantage of complementarities and decentralization to a more functional local level.