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：它们面临着日益增加的粮食需求，同时又被要求减少外部投入，尽量减少对环境的负面影响。合成氮肥的广泛使用提高了农业植物生产的生产力。然而，由于作物栽培中氮的利用效率低，氮肥的密集使用会导致植物-土壤系统通过硝酸盐淋溶和/或氮气体排放而损失，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实现联合国战略发展目标（SDG）中的几个目标，包括全球变暖（SDG 13）、负责任生产（SDG 12）、清洁水（SDG 6）和生物多样性（SDG 15）。在CATCH-BNI项目中，我们将研究捕捞作物在常规和有机农业系统中调节氮循环方面提供关键功能和服务的潜力。由土壤细菌和古菌操作的硝化过程导致铵快速转化为硝酸盐，硝酸盐易于浸出，并与反硝化和温室气体（NOx）的产生相关。虽然硝化的化学抑制已经成为限制硝酸盐损失的工具，但最近显示出几种植物物种显示出硝化抑制活性，主要是通过释放生物硝化抑制剂（BNI）。BNI的使用允许将硝化抑制策略转移到有机生产系统，并且代表了化学抑制剂应用的低成本替代方案。来自某些捕捞作物物种的组织积累具有BNI活性的化合物，其可用作绿色肥料以提高土壤肥力并降低硝化速度。例如，某些菊科植物的含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铵的积累更大。在CATCH-BNI项目中，我们将研究将具有BNI潜力的捕捞作物纳入作物轮作中，作为减缓硝化过程和保留土壤中铵的缓解策略，以及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方法，减缓土壤中铵向硝酸盐的转化，以优化目标作物的营养。为此，我们的目标是：i）鉴定在其根分泌物和/或根和芽组织中具有BNI活性的捕捞作物植物物种和/或栽培品种;（产量和NUE）; iii）确定用BNI植物材料稳定有机肥料的最佳选择和模式，以及iv）在真实的中验证-现场条件提出的创新。

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.