Investigating the fundamental mechanisms that regulate nitrogen transformations and nitrous oxide emissions in complex agroecosystems

未受干扰的生态系统向密集农业生产的转变对土壤有机质水平产生了负面影响，导致土壤碳（C）和氮（N）储量下降，并导致温室气体排放。 此外，我们越来越依赖氮肥来维持农业生产力，这增加了N2O的排放，N2O是一种温室气体，其全球变暖潜力是CO2的296倍。 目前，土壤贡献了全球N2O总排放量的70%，但随着农业生产的加剧，对氮肥的依赖程度越来越高，以满足当前和未来全球对食品，纤维和燃料的需求，预计土壤排放量将进一步增加。 如果氮可以更有效地管理，通过实施复杂的农业生态系统，如间作系统，那么需要盈余的N增加减少。 然而，这种潜力是知之甚少，和复杂的农业生态系统中的N转化的调节机制尚未被量化。 这项研究计划提供了土壤氮转化和C稳定在间作相比，单一作物，除了这些过程是如何受到大气中的CO2浓度和温度的增加。 该方法涉及严格的土壤采样，以量化土壤中的C和N在间作和单一作物，并提供数据，是有价值的模型的校准。 利用新的稳定同位素技术将有助于确定N2O的来源和总的土壤氮矿化和固定的速度。从这项研究计划中获得的信息提供了进一步的洞察复杂的农业生态系统中的N管理，并有助于目前缺乏信息的N2O分区和稳定同位素技术在不同的农业生产系统中的应用。 该研究计划解决了通过减少温室气体排放系统地实现环境目标的多种好处，同时也解决了长期维持全球粮食安全的当前问题。 这一信息对各种利益攸关方都有价值，并将促进国际协作努力。

The conversion of undisturbed ecosystems to intense agricultural production has negatively affected levels of soil organic matter, which has has led to a decline in soil carbon (C) and nitrogen (N) stocks and has resulted in the emission of greenhouse gases (GHG). Additionally, our increasing dependence on N fertilizers to maintain agricultural productivity has augmented the emission of N2O, a GHG with a global warming potential 296 times greater than that of CO2. Currently, soils contribute 70% of the total global N2O emissions, but further increases are expected as agricultural production intensifies with increasing reliance on N fertilizers to meet current and future global demands for food, fiber and fuel. If N can be managed more effectively through the implementation of complex agroecosystems, such as intercrop systems, then the need for surplus N additions decreases. However this potential is poorly understood, and the mechanisms that regulate the transformation of N in complex agroecosystems has not yet been quantified. This research program provides information on soil N transformations and C stabilization in intercrops compared to sole crops, in addition to how these processes are affected by an increase in the concentration of atmospheric CO2 and temperature. The methodological approach involves rigorous soil sampling to quantify soil C and N in intercrops and sole crops; and provides data that is valuable for the calibration of models. Use of novel stable isotope techniques will help to determine the sources of N2O and the rate gross soil nitrogen mineralization and immobilization. Information gained from this research program provides further insight into the management of N in complex agroecosystems, and contribute to the current lack of information on N2O partitioning and the application of stable isotope techniques in different agricultural production systems. This research program addresses the multiple benefits that systematically meet environmental goals through mitigating GHG emissions, but also addresses the current issue of maintaining global food security over the long-term. This information is of value for a variety of stakeholders and will foster international collaborative efforts.