Evaluation of nitrogen balances and nitrogen use efficiencies on farm level of the German agricultural sector

CONTEXT

Use of Nitrogen (N), an essential macronutrient, must be optimised in order to ensure food security and food sovereignty, mitigate negative externalities of food production and achieve ambitious (inter-)national environmental, climate and sustainability goals. Nitrogen use efficiency (NUE) is an appropriate indicator for assessing N utilisation on farms.

OBJECTIVE

The aim of the study was to evaluate N performance of the German agricultural sector, to generate knowledge gain regarding methodological design and estimating N indicators based on farm accounting data, to estimate the role and extent of externalities, and to increase understanding of interrelations between farm characteristics and N performance in order to support policymakers in finding targeted N mitigation measures.

METHODS

Using data from the German Farm Accountancy Data Network (FADN) covering 5923 farms between the years 2016/17 and 2018/19, we calculated mean farm-level NUE and N balance values for six farm types, considering input and output parameters on farm level as well as externalities. We also developed two explanatory models to identify interrelations between N performance indicators investigated, and regional, socio-economic and farm structural characteristics.

RESULTS AND CONCLUSIONS

The results indicated an increasing trend in NUE from dairy, to pig and poultry, and arable farms, but large variance within each farm type, indicating efficiency reserves in N use. Livestock farms undercut NUE and exceed N surpluses to such an extent that the sustainability goal for 2030 for the national N balance as defined in German Sustainable Development Strategy could be jeopardised. Different levels of externalisation, namely feed imports and manure exports, may deepen this gap. Multiple regression analysis revealed statistically significant interrelations between N performance and independent variables such as soil fertility, crop selection and diversity, production type, operating profit and consulting services received. Thereby, structural patterns and strategies in order to reduce N waste and increase NUE were identified. However, main source of uncertainty was due to the lack on imported manure amounts from FADN data.

SIGNIFICANCE

Determination of N performance can improve understanding the complexity of agri-environmental interrelations and support policymakers in designing appropriate policies to improve N management.