Background

Nitrogen (N) as a key input for crop production has adverse effects on the environment through emissions of reactive nitrogen. Less than 20% of the fertiliser nitrogen applied to agricultural land is actually consumed by humans in meat. Given this situation, nitrogen budgets have been introduced to quantify potential losses into the environment, to raise awareness in nutrient management, and to enforce and monitor nutrient mitigation measures. The surplus of the N soil surface budget has been used for many years for the assessment of potentially water pollution with nitrate from agriculture.

Results

For the 402 districts in Germany, nitrogen soil surface budgets were calculated for the time series 1995 to 2017. For the first time, biogas production in agriculture and the transfer of manure between districts were included in the budget. Averaged for all districts, the recent N supply to the utilised agricultural area (UAA) totals 227 kg N ha⁻¹ UAA (mean 2015–2017), among them 104 kg N ha⁻¹ UAA mineral fertiliser, 59 kg N ha⁻¹ UAA manure, 33 kg N ha⁻¹ UAA digestate, 14 kg N ha⁻¹ UAA from gross atmospheric deposition, 13 kg N ha⁻¹ UAA biological N fixation, and 1 kg N ha⁻¹ UAA from seed and planting material. The withdrawal with harvested products accounts for 149 kg N ha⁻¹ UAA, resulting in an N soil surface budget surplus of 77 kg N ha⁻¹ UAA. The N surpluses per district (mean 2015–2017) vary considerably between 26 and 162 kg N ha⁻¹ UAA and the nitrogen use efficiency of crop production ranges from 0.53 to 0.79 in the districts. The N surplus in Germany as a whole has remained nearly constant since 1995, but the regional distribution has changed significantly. The N surplus has decreased in the arable farming regions, but increased in the districts with high livestock density. Some of this surplus, however, is relocated to other districts through the transfer of manure.

Conclusions

The 23-year time series forms a reliable basis for further interpretation of N soil surface surplus in Germany. Agri-environmental programmes such as the limitation of the N surplus through the Fertiliser Ordinance and the promotion of biogas production have a clear effect on the N surplus in Germany as a whole and its regional distribution.

中文翻译：

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1995年至2017年德国各地区的氮土壤表面预算

背景

氮作为作物生产的主要投入物，会通过释放活性氮而对环境产生不利影响。实际上，人类食用肉类所消耗的肥料氮不到20％。在这种情况下，已引入氮预算来量化对环境的潜在损失，以提高对养分管理的认识，并执行和监测养分缓解措施。多年来，土壤氮素预算盈余已用于评估农业硝酸盐对水的潜在污染。

结果

对于德国的402个地区，计算了1995年至2017年时间序列的氮土壤表面预算。预算中首次包括了农业沼气生产和地区之间的粪便转移。根据所有地区的平均水平，最近对农业利用区（UAA）的氮供应总量为227 kg N ha ^-1 UAA（2015-2017年平均），其中104 kg N ha ^-1 UAA矿物肥料，59 kg N ha ^-1 UAA肥料，33 kg N ha ^-1的UAA消化物，14 kg N ha ^-1的大气总沉积UAA，13 kg N ha ^-1的UAA生物固氮和1 kg N ha ^-1来自种子和种植材料的UAA。收获产品的撤离量为149千克N ha ^-1 UAA，导致土壤氮预算盈余为77千克N ha ^-1 UAA。每个地区的氮剩余量（2015-2017年平均）在26至162 kg N ha ^-1 UAA之间变化很大，该地区作物生产的氮利用效率在0.53至0.79之间。自1995年以来，德国整体上的氮过剩几乎保持不变，但是区域分布发生了很大变化。耕作区的氮过剩有所减少，而牲畜密度高的地区则有所增加。但是，这些剩余中有一部分通过粪便转移到其他地区。

结论

23年的时间序列为进一步解释德国的土壤氮剩余量奠定了可靠的基础。农业环境计划，例如通过《肥料条例》限制氮过剩和促进沼气生产，对整个德国的氮过剩及其区域分布产生了明显影响。