ABSTRACT Land use and land cover have rapidly changed in Kham basin, northern Laos, with a rapid expansion of maize cultivated area. While maize monoculture has contributed to reduce rural poverty, many farmers are now confronted to declining yields, indebtedness, rising health and environmental concerns. Interventions at two different stages of the maize boom, i.e. expansion-intensification and distress-diversification phases, allowed capturing the main drivers of change in maize production systems, and assessing opportunities and constraints for the adoption of more sustainable maize-legume mixed systems. The successive innovations in maize cropping systems, i.e. introduction of hybrid seeds, motorized tillage, herbicides, service provision, planters, and mineral fertilizers, were mainly driven by productivity and profitability objectives. Farmers’ interest in maize-legume mixed systems was low during maize expansion-intensification phase. The decline in maize profitability and new market outlets for legumes open new opportunity windows for maize-legume mixed systems. Yet, farmers’ adoption of such systems is limited by (i) local perceptions of legumes as cash crops only, and (ii) farmers’ least effort strategies that includes e.g. heavy herbicide use and livestock free roaming after maize harvest. Large-scale adoption of maize-legume mixed systems requires innovative intervention mechanisms to engage local stakeholders into redesigning their landscapes and value-chains.

中文翻译：

---

老挝采用玉米-豆类混合种植系统的机会和限制

摘要 随着玉米种植面积的迅速扩大，老挝北部康巴盆地的土地利用和土地覆盖发生了迅速变化。虽然玉米单一栽培有助于减少农村贫困，但许多农民现在面临着产量下降、负债、健康和环境问题日益严重的问题。在玉米繁荣的两个不同阶段，即扩张-集约化和困境-多样化阶段进行干预，可以捕捉到玉米生产系统变化的主要驱动因素，并评估采用更可持续的玉米-豆类混合系统的机会和制约因素。玉米种植系统的连续创新，即引入杂交种子、机动耕作、除草剂、服务提供、种植机和矿物肥料，主要是由生产力和盈利目标驱动的。在玉米扩张-集约化阶段，农民对玉米-豆类混合系统的兴趣很低。玉米盈利能力的下降和豆类的新市场渠道为玉米-豆类混合系统打开了新的机会窗口。然而，农民采用此类系统受到以下因素的限制：(i) 当地认为豆类仅作为经济作物，以及 (ii) 农民最省力的策略，包括大量使用除草剂和玉米收获后牲畜自由漫游。大规模采用玉米-豆类混合系统需要创新的干预机制，让当地利益相关者参与重新设计他们的景观和价值链。玉米盈利能力的下降和豆类的新市场渠道为玉米-豆类混合系统打开了新的机会窗口。然而，农民采用此类系统受到以下因素的限制：(i) 当地认为豆类仅作为经济作物，以及 (ii) 农民最省力的策略，包括大量使用除草剂和玉米收获后牲畜自由漫游。大规模采用玉米-豆类混合系统需要创新的干预机制，让当地利益相关者参与重新设计他们的景观和价值链。玉米盈利能力的下降和豆类的新市场渠道为玉米-豆类混合系统打开了新的机会窗口。然而，农民采用此类系统受到以下因素的限制：(i) 当地认为豆类仅作为经济作物，以及 (ii) 农民最省力的策略，包括大量使用除草剂和玉米收获后牲畜自由漫游。大规模采用玉米-豆类混合系统需要创新的干预机制，让当地利益相关者参与重新设计他们的景观和价值链。