Les objectifs globaux du projet visent à mettre au point de manière participative, pour les exploitations de la zone cotonnière, de nouveaux modes de gestion des sols qui permettent une mise en culture (rotations et successions culturales) durable et attractive car productive et compatible avec leurs contraintes.

Sont soulignés ici la nécessité d'un bon choix des systèmes en fonction des milieux, la nécessité d'une bonne production de biomasse et et de sa protection contre les feux et les animaux. Il faut également veiller à introduire les soles fourragères dans les rotations et à pérenniser les systèmes et surtout ne pas revenir au labour.

Diaporama sur rendements en maïs et sorgho associés ou non, et en coton sur labour, Semis direct et SCV, données agro-éco et production de biomasse sur projet ESA au Nord Cameroun

Ce dossier consacré à cette nouvelle agriculture, est le fruit d'une collaboration entre l'AFD, le Cirad, le MAE et le FFEM. Il a pour objectif de faire connaître cette véritable révolution agronomique au-delà du petit cercle des chercheurs impliqués. Nous espérons que ce dossier apportera une contribution utile aux efforts déployés par tous les partenaires des actions soutenues par l'aide française dans ce domaine, pour promouvoir une agriculture à la fois rentable et durable. La dégradation des sols dans le monde n'est pas une fatalité. Nous pouvons donner aux générations actuelles et futures les moyens de s'en préserver.

Diaporama upon 2 cases in Brasil (1 in cerrados, 1 in Parana subtropical): Evolution of the O.M. in quantity & quality with differents systems (DMC and till conventional)

Rapport d'activité annuel sur exploitations et expérimentations en milieu paysan, avec rendements, biomasse et temps de travaux sur SCV avec cultures de coton sorgho, maïs

In China, the central and the provincial governments of Yunnan launched a series of reforms to address the problems of upland development during the 1990s. These reforms were based on the premise that the best strategy for addressing the problems of upland development is to promote intensification of land use so that farmers’ food needs are met from a smaller area. The land and labor resources formerly tied to meet the food needs can then be released for the production of in come-generating cash crops and also for environmental purposes. Guided by this strategy, the government promoted improved upland rice technologies and initiated other reforms to encourage land use intensification. Anecdotal evidence indicates that this strategy is making a positive impact on farmers’ livelihoods and the environment by inducing desirable changes in land use patterns.

About 250 farmers have tried comparing cereal cultivation under direct seeding mulch-based cropping systems (DMC) against the traditional cropping practices from year 2001 to 2004. The on-farm tested systems include mixed cropping of a cereal (maize, sorghum, millet) and a cover crop (mucuna, brachiaria, crotalaria, cowpea, dolichos). These mixed cropping practices are done for the following objectives: 1) Produce aboveground biomass to build-up mulch for the following season's crop (mainly cotton). 2) Soil improvement through the physical and chemical (produce N) contribution of the associated plants. 3) Forage production. 4) Weed control. 5) Protect the soil surface against erosion and rain impact. 6) Produce consumable grains for man and animals. Up till present the tested plants meet the above objectives differentially and are adapted to the local agro climatic conditions of North Cameroon (rainfall from 700 to 1200 mm). Thus Brachiaria ruzisiensis produces aboveground biomass in quantities (4-5 t/ha even under mixed cropping) and quality (persisting as mulch for over one year after production). Further, it is very efficient in controlling Striga and is a good forage crop. However, it can impoverish the soils if its biomass is exported several times without any fertiliser supplements since it is not a nitrogen fixing plant. On the contrary Crotalaria retusa is a nitrogen fixing plant and therefore enriching the soils. This plant is less palatable to animals and therefore advantageous to farmers who cannot protect their farmland from pasturing animals in the dry season. It is equally very efficient in controlling weeds. Four years of experimentation has enabled us to produce practical recommendations in mixed cropping on the following : sowing date, crop type, tolerance to herbicides, competition with cereals, etc. This experimentation has also enabled us to see how the various plants tie with the above-mentioned objectives. On-going research work is on the following: 1) Diversifying the range of plant material available, focusing on local varieties. 2) Extending these cropping techniques to cover vertisols covering tens of thousands of hectares in North Cameroon. 3) Introducing these plants at the beginning and at the end of the cycle of the main crop in order to better use early and the late rains.

Farming systems throughout the Lao PDR have changed drastically over the last 15 years due to a range of factors. In some areas where market forces are prevalent, shifting cultivation systems have given way to more conventional high-input agricultural systems. In other more remote areas, the traditional swidden system with long rotations has been put under pressure primarily due to modification of land access and increasing population pressure. In southern Xayabury in the Mekong corridor, where there is access to the Thai market, land preparation has become based on burning residues and ploughing on steep slopes. Because of the environmental and financial costs of land preparation, farmers are shifting to herbicides, which lead to chemical pollution, while crop residues and weed mulch are usually burned, thereby increasing mineral losses and erosion on bare soil. In mountainous areas such as Xieng Khouang Province, the rationale of shifting cultivation is collapsing as farmers use land for longer periods of cropping and return more frequently to each field. A holistic research approach has been implemented in Xayabury and Xieng Khouang to find direct seeding mulch-based cropping (DMC) systems that are compatible with farmers' strategies and which can be reproduced inexpensively on a large scale. The methodological framework, based on five main components, emphasises the process of adaptation and validation by farmer groups, meaning that priorities are defined by smallholders in light of the constraints of their farming systems and the overall environmental conditions.

Diaporama about soil fauna, biomasses of macro & microfauna, comparison between bare soil et straw, litter quality.