Improved nitrogen use efficiency in agriculture by CATCH crops as producers of Biological Nitrification Inhibitors

工业化国家的农业系统面临着重大挑战：它们在被要求减少外部投入和尽量减少对环境的负面影响的同时，也面临着日益增长的粮食需求。合成氮肥的广泛使用提高了农业植物生产的生产力。然而，由于作物栽培中氮素利用率低，集约使用氮肥会通过硝酸盐淋失和/或氮气排放从植物-土壤系统中损失，导致水和大气污染。旨在优化氮肥管理和减少氮素损失的战略有助于联合国战略发展目标(SDG)中的几个，这些目标涉及全球变暖(SDG13)、负责任的生产(SDG12)、清洁水(SDG6)和生物多样性(SDG15)。在CATCH-BNI项目中，我们将调查捕获作物在常规和有机农业系统中提供氮循环调节的关键功能和服务的潜力。土壤细菌和古生菌的硝化过程导致铵快速转化为硝酸盐，这很容易淋失，并与反硝化和温室气体(NOx)的产生有关。虽然化学抑制硝化作用已成为限制硝酸盐损失的一种工具，但最近有几种植物表现出硝化抑制活性，主要是通过释放生物硝化抑制物(BNI)。BNIS的使用允许将硝化抑制策略转移到有机生产系统，并代表了应用化学抑制剂的一种低成本替代方案。某些捕获作物的组织中积累了具有BNI活性的化合物，可以作为绿肥使用，以提高土壤肥力，减缓硝化速度。例如，一些十字花科含有硫代葡萄糖苷的植物组织就是这种情况，在用它们的组织改良的土壤中观察到了更大的铵积累。在CATCH-BNI项目中，我们将研究将具有BNI潜力的捕获作物纳入作物轮作中，作为减缓硝化过程和在土壤中保留氨氮的缓解策略，并为随后的目标作物增加土壤氮库。CATCH-BNI项目的主要目标是设计创新的方法，减缓土壤中铵转化为硝酸盐的速度，以优化目标作物的营养。为此，我们的目标是：i)确定在其根分泌物和/或根和地上部组织中具有BNI活性的捕获作物物种和/或品种；ii)了解产生BNI的捕获作物的使用对N循环的影响的效率以及目标作物的表现(产量和氮效率)；iii)确定使用BNI植物材料稳定有机肥料的最佳选择和方式；以及iv)在真实的田间条件下验证所提出的创新。

Agrosystems in industrialized countries are confronted with important challenges: they are facing increasing food demand while they are requested to reduce external inputs and to minimize negative environmental impact. The widespread use of synthetic nitrogen (N) fertilizers has promoted the productivity in agricultural plant production. However, due to the low N use efficiency in crop cultivation, the intensive use of N fertilizers entails losses from the plant-soil system via nitrate leaching and/or N gas emissions, leading to water and atmosphere pollution. Strategies aiming at optimizing N fertilizer management and reducing N losses contribute to several of the UN Strategic Development Goals (SDGs) dealing with global warming (SDG13), responsible production (SDG12), clean water (SDG6) and biodiversity (SDG15). In the CATCH-BNI project, we will investigate the potential of catch crops to provide key functions and services in the regulation of N cycling in conventional and organic agrosystems. The nitrification process operated by soil bacteria and archaea leads to rapid conversion of ammonium into nitrate, which is prone to leaching, and associates with denitrification and the production of greenhouse gases (NOx). While chemical inhibition of nitrification has emerged as a tool to limit nitrate losses, several plant species were lately shown to display nitrification inhibiting activities, mostly through release of Biological Nitrification Inhibitors (BNIs). The use of BNIs allows transferring the nitrification inhibition strategy to organic production systems and represents a low-cost alternative to the application of chemical inhibitors. Tissues from certain catch crop species accumulate compounds with BNI activities, which can be used as green manure to improve soil fertility and reduce the speed of nitrification. This is e.g. the case for glucosinolate-containing plant tissues from some Brassicaceae, for which a greater accumulation of ammonium was observed in soils amended with their tissues. In the CATCH-BNI project we will investigate the incorporation of catch crops with BNI potential into crop rotations as a mitigation strategy to slow down nitrification processes and retain ammonium in soils as well as to increase soil N pools for the subsequent target crop.The main objective of the CATCH-BNI project is to design innovative approaches slowing down the conversion of ammonium to nitrate in soils for optimized nutrition of target crops. For this, we aim at: i) identifying catch crop plant species and/or cultivars with BNI activities in their root exudates and/or root and shoot tissues; ii) understanding how efficiently the N cycle is impacted by the use of BNI-producing catch crops and how the target crops perform (yield and NUE); iii) determining the best options and modalities to stabilize organic fertilizers with BNI plant material and iv) validating in real-field conditions the proposed innovations.