Nitrogen-use efficiency of organic and conventional arable and dairy farming systems in Germany

Lucie Chmelíková,Kurt-Jürgen Hülsbergen,Harald Schmid,Sandra Anke

doi:10.1007/s10705-021-10126-9

Lucie Chmelíková, Kurt-Jürgen Hülsbergen + Show 2 more

Open Access

https://doi.org/10.1007/s10705-021-10126-9

Copy DOI

Abstract

Optimising nitrogen (N) management improves soil fertility and reduces negative environmental impacts. Mineral N fertilizers are of key importance in intensive conventional farming (CF). In contrast, organic farming (OF) is highly dependent on closed nutrient cycles, biological N fixation and crop rotations. However, both systems need to minimise N balances and maximise nitrogen-use efficiency (NUE). NUE of organic and conventional crop production systems was evaluated in three regions in Germany by analysing N input, N output and N balance of 30 pairs of one OF and one CF farm each from the network of pilot farms for the period 2009–2011; indicators were calculated using the farm management system REPRO. CF had higher N input in all farm pairs. In 90% of the comparisons, N output of CF was higher than OF, in 7% it was the same and in 3% lower. NUE was higher in 60% of the OF, the same in 37% and lower in only 3%. The NUE of crop production in OF was 91% (arable farms: 83%; mixed/dairy farms: 95%) and the NUE in CF was 79% (arable farms: 77%; dairy farms: 80%). N balance was lower in 90% of the OF. The yearly average N balance was four times higher in CF (59 kg N ha−1 a−1) than in OF (15 kg N ha−1 a−1). The results show a huge individual variability within OF and CF. Organic mixed/dairy farms had the lowest N balances and the highest NUE. A further expansion of OF area can help to reduce high N balances and increase the NUE of crop production.

Highlights

In Western Europe, high nitrogen (N) balances have been reported in agriculture for decades, leading to N losses in the form of ammonia, nitrous oxide emissions and nitrate losses to groundwater, which can have negative environmental effects and contribute to climate change (Blanke et al 2018; Bleken et al 2005; van Grinsven et al 2012)
High N balances are found on intensive conventional arable farms (Biernat et al 2020)
In compared to OF (CF), mainly maize for fodder production and root crops made up a large proportion of the crop rotation

Summary

Introduction

In Western Europe, high nitrogen (N) balances have been reported in agriculture for decades, leading to N losses in the form of ammonia, nitrous oxide emissions and nitrate losses to groundwater, which can have negative environmental effects and contribute to climate change (Blanke et al 2018; Bleken et al 2005; van Grinsven et al 2012). The causes are complex (Wiesler et al 2016) Despite technical innovations such as improved liquid manure application technology, the use of stabilized N fertilizers (Petersen et al 2013), and sensor-supported, site-specific fertilization (Prey and Schmidhalter 2019), N balances have not decreased significantly. This is due to the further expansion, intensification and regional concentration of livestock farming with high levels of slurry usage. A few studies have analysed how the structure of organic farms (e.g. arable farms and dairy farms) and the fertilization intensity (N input) influence the N balance and nitrogen-use efficiency (NUE)

Objectives

Methods

Results

Discussion

Conclusion