Abstract：
Nitrogen (N) budgets are valuable tools to increase the understanding of causalities between agricultural production and N emissions to support agri-environmental policy instruments. However, regional agricultural N budgets for an entire country covering all major N flows across sectors and environmental compartments, which also distinguish between different N forms, are largely lacking. This study comprehensively analyses regional differences in N budgets pertainting to agricultural production and consumption in the largely alpine and spatially heterogeneous country of Austria. A special focus is on the interconnections between regional agricultural production systems, N emissions, nitrogen use efficiencies (NUE), and natural boundary conditions. Seven regional and one national balance are undertaken via material flow analysis and are analysed with regards to losses into soils, water bodies and atmosphere. Further, NUE is calculated for two conceptual systems of plant and plant-livestock production. The results reveal major differences among regions, with significant implications for agri-environmental management. The high-alpine region, characterized by alpine pastures with a low livestock density, shows consequent low N inputs, the lowest area-specific N outputs and the most inefficient NUE. In contrast, the highest NUE is achieved in a lowland region specialized in arable farming with a low livestock density and a predominance of mineral fertilizer over manure application. In this region, the N surplus is almost as low as in the high-alpine region due to both significantly higher N inputs and outputs compared to the high-alpine region. Nevertheless, due to low precipitation levels, widespread exceedances of the nitrate target level concentration take place in the groundwater. The same issue arises in another non-alpine region characterized by arable farming and high livestock densities. Here, the highest N inputs, primarily via manure, result in the highest N surplus and related nitrate groundwater exceedances despite an acceptable NUE. These examples show that NUE alone is an insufficient target and that adapted criteria are needed for different regions to consider natural constraints and specific framework conditions. In a geographically heterogeneous country like Austria, the regional circumstances strongly define and limit the scope and the potential effectiveness of agricultural N management strategies. These aspects should be integrated into the design, assessment and implementation of agri-environmental programmes.
摘要：
氮（N）预算是增加对农业生产与氮排放之间因果关系的理解以支持农业环境政策工具的宝贵工具。然而,整个国家的区域农业氮素预算，涵盖所有部门和环境分区的主要氮素流动，这也区分了不同的N种形式，基本上缺乏。这项研究全面分析了奥地利这个高山和空间异质性国家对农业生产和消费的影响。特别关注区域农业生产系统之间的相互联系，N排放,氮利用效率(NUE)，自然边界条件。通过物质流分析进行了七个区域和一个国家的平衡，并对土壤流失进行了分析，水体和大气。Further,NUE是针对植物和植物-牲畜生产的两个概念系统计算的。结果揭示了地区之间的主要差异，对农业环境管理具有重要意义。高寒地区,以牲畜密度低的高山牧场为特征，显示了随之而来的低N输入，最低的区域特定N输出和最低效的NUE。相比之下,最高的NUE是在低地地区实现的，该地区专门从事耕种，牲畜密度低，矿物肥料多于肥料施用。在这个地区,由于与高寒地区相比，N的投入和产出明显更高，因此N的盈余几乎与高寒地区一样低。然而，由于降水水平低，地下水中硝酸盐目标浓度的广泛超标。同样的问题也出现在另一个非高山地区，其特征是耕种和高牲畜密度。这里,最高的N个输入，主要是通过粪肥，尽管NUE可接受，但仍导致最高的氮过剩和相关的硝酸盐地下水超标。这些示例表明，仅NUE是一个不足的目标，并且不同地区需要适应的标准来考虑自然约束和特定框架条件。在像奥地利这样地理异质的国家，区域环境强烈定义和限制了农业氮素管理策略的范围和潜在有效性。这些方面应该融入到设计中，农业环境方案的评估和实施。
