Reducing nitrogen impacts in northern Indian cropping systems: realising production and environmental benefits

不断增长的世界人口要求不断增加的粮食供应。作物产量的增加主要是由于合成氮肥的生产和应用，以及对氮素反应灵敏的品种的选择，使整个20世纪的人口持续增长。然而，氮肥的使用引起了全球的关注，因为除了对淡水和海洋生态系统的破坏外，它还与导致气候变化的高水平能源使用和温室气体排放有关。在包括小麦和水稻在内的谷类作物中，要获得高产，需要施氮肥。由于生产产量、农民收入和主食供应的下降，通过减少氮肥投入来提高可持续性迄今已被证明是困难的。此外，印度(和其他发展中国家)目前对化肥定价的政策(以及相关补贴)干预的现状，支持高施肥率以推动产量。这导致了许多结果，其中许多结果不利于长期可持续性。此外，这种氮素需求推动了合成肥料产量的持续增长(如右图所示)，这是一个能源密集型过程，导致了额外的排放和能源成本。迄今为止，我们在氮素挑战方面的工作已经对英国和印度的谷物种植产生了重大影响，方法是开发了一个优化氮素使用的新框架(英国)，并通过直接干预耕作实践来减少Bassian村农民田地的氮素使用量(一种基于颜色的确定最佳氮肥用量的方法，称为PAU-LCC，印度)。我们在理解减少氮肥使用量的潜力方面迈出了重要的一步，而不会损害农民的生产力或经济回报。这项翻译建议建立在这些成果的基础上，以确保我们实现它们在印度农业可持续发展方面的全部价值。我们与社会福利非政府组织Atam Pargas和Bassian村的农业社区建立了坚实的基础伙伴关系，这为集中交付影响提供了重要框架，也是印度未来体制转型的典范。我们将继续将我们的工作建立在这一平台上，目的是使Bassian村的所有作物生产都利用PAU-LCC来确定最佳的氮肥施用量。此外，这个翻译项目将解决我们根据迄今的工作确定的两个主要差距。第一种方法是量化和评估在当地(村庄)范围内减少氮肥使用的环境效益，以便计算全氮预算，以反映为减少氮肥使用而采取的简单干预措施的影响。第二个是围绕减氮干预措施参与印度农业政策议程的框架。印度的农业政策与未来的农业可持续性有着千丝万缕的联系，并将在很大程度上决定我们项目中的实际干预和监测的成功程度，因此，这一框架对于实现我们工作的全面影响至关重要。

A growing world population requires a growing food supply. The rise in crop yields resulting mainly from the production and application of synthetic nitrogen (N) fertilizer together with the selection of N responsive varieties sustained population growth throughout the 20th century. However, N fertiliser use is of global concern because it is associated both with high levels of energy use and greenhouse gas emissions that cause climate change, in addition to damage to fresh water and marine ecosystems. N fertilisation is required for achieving high yield in cereal crops including wheat and rice. Increasing sustainability through a decrease in N fertiliser inputs has to date proved difficult due to the resulting fall in productive yield, farmer income and staple food supply. In addition, the current status of policy (and associated subsidy) intervention in fertiliser pricing in India (and other parts of the developing world) supports high application rates to drive yields. This leads to numerous outcomes, many of which are unfavourable for long-term sustainability. In addition this N demand drives the continual growth of synthetic fertiliser production (shown right), an energy intensive process resulting in additional emission and energy costs.Our work on the N challenge to date has delivered major impacts to both UK and Indian cereal cropping through development of a new framework for optimising N use (UK) and through a direct intervention in farming practice to reduce N use in farmers' fields in Bassian village (a colour-based method of determining optimal N rate called the PAU-LCC, India). We have provided important step changes in our understanding of the potential to reduce N fertiliser use without compromising productivity or economic returns to farmers. This translational proposal builds on these outcomes to ensure that we realise their full value in terms of agricultural sustainability in India. We have established a solid foundational partnership with the social welfare NGO Atam Pargas and the farming community in Bassian village, which provides an important framework for focussing the delivery of impact and is a model for future system transformation in India. We will continue to base our work on this platform with the aim that all crop production in Bassian village makes use of the PAU-LCC for determining optimal N application. Additionally, this translational project will address two of the major gaps that we have identified based on our work to date. The first is a means to quantify and assess environmental benefits of reduced N fertiliser application at the local (village) scale allowing for the calculation of a full N budget to reflect the impact of simple interventions to reduce N use. The second is a framework for engaging in the Indian agricultural policy agenda around N reduction interventions. Agricultural policy in India is intricately linked to future agricultural sustainability and will largely determine how successful the practical interventions and monitoring in our project are so this framework will be crucial for realising the full impact of our work.