In Laos, the agrarian transition is characterized by rapid changes in agricultural production systems. Since the early 2000s, a transition has been taking place, away from subsistence agriculture, primarily based on rice cultivation, forest gathering and extensive livestock farming, and towards market-oriented agricultural production systems, with a significant and rapid increase in crops grown for export (Figure 5.1) to neighbouring countries, mainly China, Thailand and Vietnam. This transition has been facilitated by the implementation of successive public policies to limit the use of shifting cultivation and to modernize agriculture (Box 5.1), and by the result of the country becoming

The world today is facing many challenges, among which demographic pressure and the natural resources of the earth, we are reaching the limits of. The demographic factor is directly linked with the food security issue since it is imperative that we produce more in order to feed our growing population. To this must be added the evolution of alimentary diet which accompany the progressive improvements we have seen in the lives of the poorest segments of the population. Having reached the outer physical limits of our planet, we can only intensify each farming acre’s productivity so as to preserve the natural areas still left to us, such as forests, while avoiding the non-sustainable development of marginal lands. When we include the stakes related to nutrition and climate change, it is easy to understand the complexity of the challenges facing us. This is particularly true in Southeast Asia due to the immense demographic pressure felt in most countries1.

Séminaire Agroécologie - Intensification écologique des systèmes de culture de Montpellier du 06.05.2014 : Agriculture de conservation et biomasse : nourrir le sol et/ou le bétail? / K. Naudin (Unité Cirad Aïda), O. Husson L’agriculture de conservation (AC) repose sur la production et la conservation de la biomasse sur la parcelle. Les fonctions remplies par la biomasse peuvent être nombreuses : (i) en tant que couverture végétale : réduction de l’érosion, amélioration du bilan hydrique des cultures, contrôle de l’enherbement, apport en carbone et en azote, recyclage des nutriments, augmentation de l’activité biologique, etc.) ; (ii) en tant que combustible domestique ou industriel ou ; (iii) en tant que fourrage. Dans de nombreux pays en voie de développement la biomasse aérienne des plantes, cultivées ou non, sert à alimenter le bétail. Cette compétition pour l’utilisation de la biomasse est une des causes majeures de la difficulté de la pratique de l’AC, d’autant plus que l’accès aux parcelles après la culture est souvent libre (vaine pâture) et que la pression du bétail est importante. Il s’agit donc de rechercher des compromis entre des fonctions agronomiques de la biomasse à l’échelle de la parcelle et des fonctions à l’échelle de l’exploitation. Ces compromis portent sur les différentes fonctions agronomiques entre elles ou entre ces fonctions agronomiques et l’exportation pour alimenter les animaux. Ils ont jusqu’ici été peu traités, ni dans la littérature scientifique, ni dans la littérature technique.

Constrained by a hilly topography and long distances to the main economic centers of the province, agriculture in the northern part of Kham district has long been dominated by traditional slash-and-burn shifting cultivation. In general, the plots are cropped with glutinous rice during one year, sometimes planted with traditional maize varieties the following year, and left fallowed for 3 to 15 years depending on the distance of the plot to the village and the associated land pressure. In these forested environments, NTFPs are traditionally an important source of food.

With limited opportunities for agricultural expansion in the lowlands (i.e. most of the lowland areas have already been converted into paddy fields), increasing rice production representsa key challenge for the subsistence farmers of the plain of Jars. Yet, in the quasi-absence of chemical fertilization, the productivity of lowland agriculture is strongly linked to upland cattle breeding and the availability of manure

Since the opening of the country to the market economy in 1986, the Government of Laos (GoL) has invested considerable efforts into modernizing its agriculture. Village land use planning and land registration are being used by the GoL to promote an intensification of agriculture - from extensive subsistence-oriented shifting cultivation, deemed unproductive and poverty-creating, to more intensive and market-oriented cropping systems

Adoption of SVC by smallholders in Laos

Since the mid-2000s, land-use in Kham basin and Nonghet hillsides has come to be dominated by hybrid maize mono-cropping. The rapid expansion of this commercial crop has a tremendous impact on both the local economy and the environment. Maize has not only replaced existing gardens, chilli and fruit tree plantations but it has also expanded at the expense of forests and former fallow land. With the transition towards intensive commercial agriculture, agricultural productivity has increased considerably while rural poverty has receded. Yet, a growing number of farmers are now confronted with land degradation issues (e.g. soil erosion, lowland siltation, weed pressure and chemical pollution), excessive production costs and indebtedness. In this context, the activities promoted by PRONAE have focused on accompanying the ‘maize boom’ and, in particular, mitigating its potentially negative impacts by developing DMC-based maize cropping systems.

In the mountainous areas of northern Vietnam, the increasing population pressure, the changes in land tenure and the economic reforms at the beginning of the 1990’s led to the return to traditional slash-and-burn cultivation practices and to a fast development of livestock herd. However, competition for natural resources led to a downward spiral of ra pid forest degradation, soil compaction caused by over-grazing, decreasing crop yields, crop damages by animals, and fodder shortage and sanitary problems for the livestock leading to a high mortality. Des techniques de semis direct, basées sur l'amélioration du sol par la culture d'espèces ayant des systèmes racinaires forts et la capacité de produire une quantité importante de biomasse même sur des sols dégradés produisent également les fourrages qui peuvent être employés pour l'alimentation animale. Le fumier obtenu, par cette intégration de l'élevage au système de semis direct améliore le fonctionnement des systèmes de culture. Ainsi, l'exploitation agricole bénéficie de ces techniques : l'alimentation et les performances du système sont accrues, tout en optimisant l'utilisation des ressources de ces systèmes (préservation ou même amélioration du sol, réduction des goulots d'étranglements pour l'utilisation de la main-d'oeuvre). Les possibilités d'intégration de l'élevage et des cultures grâce à ces techniques facilitent l'adoption par les exploitants agricoles car elles concernent l'ensemble des composantes de la production et non plus un élément.

Diaporama sur les érosions en zone montagneuse, et les moyens de les contrôler et les régénérer par systèmes SCV