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Agroecology is a promising way to synergize climate change mitigation and adaptation. It builds on the practices and knowledge of smallholder farmers to address food insecurity while reducing dependence on fossil fuels and avoiding land degradation. However, bringing agroecology to scale remains an important challenge when it comes to addressing the broader policy, social and economic contexts. Agroecology research and resulting evidence on what makes the application of agroecology principles successful are typically generated at small spatial scales. Policies instruments and intervention mechanisms that would create enabling conditions for local agroecological innovations on a large scale are still largely missing. We investigated the approaches, methods and resources employed by research-development stakeholders to promote agroecological practices in Southeast Asia. We considered two dimensions related to the modalities of intervention, namely (i) push-pull interventions and (ii) transition-conversion approaches. The first dimension refers to the distinction between push interventions – where financial, technical, material and/or organizational support is provided to targeted actors allowing them to modify their practices (e.g. subsidies and farm extension work) – and pull interventions that target the broader social and economic conditions in which actors make decisions in order to favour desired practices (e.g. sensitization and price premiums, regulations on agricultural practices e.g. restricted pesticide use). The second dimension refers to a practical opposition between approaches that promote a strict conversion from one set of practices to another seen as more desirable and approaches that allow (or even plan) for a transition between different practices. We illustrate these multiple dimensions of transformative adaptation through concrete examples related to conservation agriculture and organic farming in Laos and Cambodia.

More than 25 lessons will bring you to an agricultural knowledge as such as Agroecology, Agronomy, Rural Development or Agriculture Technology Machinery in Cambodia and South-East Asia.

The political and territorial reintegration strategy that had been implemented in Cambodia to establish peace and order in the late 1990s caused the degraded evergreen forestlands to be allocated to the demobilized Khmer Rouge families in the western regions of the country. The increasing regional demand for cereals and tubers and the highland saturation in central rice areas have driven massive immigration of smallholder farmers. Almost half a million hectares of those forestlands were thus converted in less than 15 years for annual upland cash crops development. This dramatic expansion of agricultural area, without any plan for sustainability, has exerted tremendous pressures on the natural forest resources and on biodiversity. Its effects rapidly spread on the water and soil resources of Cambodia. With conventional practices and more frequent flooding and incidents of drought, smallholder farmers could hardly sustain their livelihoods, which are mainly based on annual upland farming. Farmers with investment capacity have shifted to planting tree crops and/or to animal production in order to cope with the hazardous phenomena. This case story presents the collaborative R&D program between farmers and researchers in Battambang and Kampong Cham provinces in Cambodia. The program aimed to restore soil fertility and build the resilience of smallholder farmers to the effects of climate change while improving crop productivity and profitability of the smallholder farmers. Using the Diagnosis, Design, Assessment, Training and Extension (DATE) methodology, the project implementers designed, tested, and evaluated crop production systems that are grounded on the principles of conservation agriculture (CA). DATE is a multi-scale, multi-stakeholder participatory approach. It integrates scientific and tacit knowledge, and is composed of four components: agrarian systems diagnosis, field experiment, on-farm assessment, and pre-extension. A number of CA-based cropping systems have been designed and validated in the program: (1) mono-cropping of maize in association with pigeon pea or mungbean as relay crops, (2) biannual rotation cropping of maize with soybean or cassava, and (3) intensified cropping of maize and cassava. Synergizing this with the benefits of CA, each system has the capacity for climate change adaptation and mitigation, to retain soil fertility, and to increase smallholder farmers' profitability. Based on the results, pigeon pea is the most suitable crop for mollisols used with maize since it can improve the water retention capacity of the soil, reduce soil evaporation, and reduce mineral nitrogen inputs. Moreover, its grain can be sold or used as animal feed to augment farmers' income, a characteristic that smallholders look for in an agricultural production system. Likewise, shifting mungbean to be sown by hand broadcast after harvesting early maize significantly reduces farmers' risks and costs, thereby improving their productivity. Shifting to CA-based cassava production (a key annual crop) using chisel to operate strip tillage on planting rows after the early maize harvest also enables farmers to significantly minimize risks and costs. These risks and costs are estimated to be about USD (United States Dollar) 300–400 per hectare and USD 200 per hectare, respectively. Designing CA-based cropping systems based on the DATE methodology presents clear benefits. DATE is a holistic approach for identifying technical, socioeconomic, and institutional elements for a sustainable and more inclusive intensification of smallholder farmers' agricultural production systems. However, designing such innovative techniques is a combination of context-specific and context-generic features. These issues need to be taken into account should such innovation be replicated in other regions. In addition, this action-research program should be a continuous process; the agro-technical performances of the introduced cropping systems should be continuously validated in multiple locations and for several years. The outcomes of the cropping systems should also be continuously monitored such that their impacts on natural resources (e.g., soil organic carbon, nutrient cycles, xenobiotic dynamic, etc.) can be determined and measured accurately.

Cambodia has been identified to be one of the most affected countries by climate change. In the past two decades, migration from the central plains to the peripheral areas changed drastically the development of the uplands, inducing tremendous degradation of natural resources. The promotion of cropping systems based on ecological intensification is of paramount importance to strengthen the resilience of small-scale farming, to mitigate the effect of climate change and to advance in farm sustainability. The aim of this study was to quantify the short-term impact of conservation agriculture (CA, direct seeding + use of cover/relay crops), on soil organic C (SOC), soil total N (STN), labile C fractions (particulate organic C - POC and permanganate oxidizable organic C - POXC), β-glucosidase and arylsulfatase activities. Established in 2009, the experimental plots were laid out in a randomized complete block design (3 replicates) with: (i) soybean under conventional tillage (CT), (ii) soybean under conservation agriculture (CA1), and (iii) soybean in bi-annual rotation with maize under conservation agriculture (CA2). Several cover/relay crops were associated prior to and with the main crops. Soil sampling was conducted in 2011 and 2013 at 0-5, 5-10, 10-20, and 20-40 cm depths. Biomass-C inputs ranged from 2.2 to 7.8 Mg C ha-1 yr-1 under CT and CA respectively, emphasizing the difference of supply of fresh organic matter. On average, CA increased SOC and STN stocks at 0-5 cm depth by 20% and 25% when compared with CT. β-glucosidase and arylsulfatase activities at 0-5 cm depth was 28% and 36% greater in CA1 and CA2 soils. In addition, CA2 (rotational sequence and higher biomass-C inputs) showed a better increasing trend of labile C fraction (HWEOC and POXC) and β-glucosidase and arylsulfatase activities than CA1. Conservation agriculture shows potential for the long term improvement of Cambodia uplands. (Texte intégral)

The production of annual cash crops (soybean, maize, cassava) in upland rainfed agriculture has been practised for more than 60 years in Cambodia. Today it is an important dimension in the development of smallholder agriculture on the western and northern pioneer fronts. Current tillage-based cropping systems induce soil depletion, weakening the production systems. A 9-year R&D program, initiated in 2004, has implemented the DATE methodology (Diagnosis, Design, Assessment, Training and Extension) to adapt direct-sowing mulch-based cropping alternatives for the sustainable production of soybean, maize and cassava on-farm, with and for farmers. The cropping systems that have developed integrate cover crops for biomass input to allow a rapid improvement of production capacity, even when instituted on severely degraded soil, setting the technical basis for sustainable agriculture that needs limited inputs of agrochemicals and that is adapted to smallholders conditions.