Intensification of groundwater irrigation is central to goals of improving food security and reducing chronic poverty faced by millions of rural households across the eastern Indo-Gangetic Plains (EIGP) of Nepal and parts of eastern India. At present, levels of groundwater use and access in the EIGP lag far behind other areas of South Asia despite abundant available groundwater resources. A key reason for prevailing access constraints is the dependence on diesel pumpsets for accessing groundwater, which are typically unsubsidised and therefore expensive to purchase and operate. To date, efforts to reduce access costs have focused almost exclusively on how to incentivise adoption of alternative electric or solar-powered pumping technologies, which are viewed as being cheaper to operate and less environmentally damaging due to their lower operational carbon emissions. In contrast, there has been little attention paid to identifying opportunities to make existing diesel pump systems more cost effective for farmers to operate in order to support adaptation to climate change and reduce poverty. In this study, we use evidence from 116 detailed in-situ pump tests along with interviews with pumpset dealers, mechanics and farmers in the Nepal Terai to assess how and why fuel efficiency and operational costs of diesel pump irrigation are affected by farmers’ pumpset selection decisions. We show that costs diesel pumpset irrigation can be reduced significantly by supporting and incentivising farmers (e.g., through equipment advisories, improved supply chains for maintenance services and spare parts) to invest in newer low-cost, portable and smaller horsepower pumpset designs that are more effectively matched to local operating conditions in the EIGP than older Indian manufactured engines that have historically been preferred by farmers in the region. Such interventions can help to unlock potential for intensified irrigation water use in the EIGP, contributing to goals of improving agricultural productivity and resilience to climate extremes while also strengthening farmers capacity to invest in emerging low-carbon pumping technologies.

加强地下水灌溉是改善粮食安全和减少尼泊尔东部印度恒河平原 (EIGP) 和印度东部部分地区数百万农村家庭面临的长期贫困目标的核心。目前，尽管可用地下水资源丰富，但 EIGP 的地下水使用和获取水平远远落后于南亚其他地区。普遍存在获取限制的一个关键原因是对获取地下水的柴油泵组的依赖，这些泵组通常没有补贴，因此购买和运营成本很高。迄今为止，降低获取成本的努力几乎完全集中在如何激励采用替代电力或太阳能泵技术上，由于其较低的运营碳排放，它们被视为运营成本较低且对环境的破坏较小。相比之下，很少有人关注寻找机会使现有的柴油泵系统对农民的运营更具成本效益，以支持适应气候变化和减少贫困​​。在这项研究中，我们使用来自 116 个详细现场泵测试的证据以及对尼泊尔特莱的泵组经销商、机械师和农民的采访，以评估农民泵组选择如何以及为何影响柴油泵灌溉的燃料效率和运营成本决定。我们表明，通过支持和激励农民（例如，通过设备咨询、改进的维护服务和备件供应链）投资于更新的低成本、便携式和更小的马力泵组设计，与过去一直受到农民青睐的印度制造的旧发动机相比，这些设计更有效地匹配 EIGP 的当地操作条件地区。此类干预措施有助于释放 EIGP 中强化灌溉用水的潜力，有助于提高农业生产力和抵御极端气候的目标，同时增强农民投资新兴低碳抽水技术的能力。便携式和更小的马力泵组设计，与该地区农民历来喜欢的旧印度制造发动机相比，更有效地匹配 EIGP 当地的操作条件。此类干预措施有助于释放 EIGP 中强化灌溉用水的潜力，有助于提高农业生产力和抵御极端气候的目标，同时增强农民投资新兴低碳抽水技术的能力。便携式和更小的马力泵组设计，与该地区农民历来喜欢的旧印度制造发动机相比，更有效地匹配 EIGP 当地的操作条件。此类干预措施有助于释放 EIGP 中强化灌溉用水的潜力，有助于提高农业生产力和抵御极端气候的目标，同时增强农民投资新兴低碳抽水技术的能力。