Simulation-based assessment of residue management to mitigate N loss risk in winter wheat production

Nutr Cycl Agroecosyst (2024) 128:53–71 https://doi.org/10.1007/s10705-023-10331-8 ORIGINAL ARTICLE Simulation‑based assessment of residue management to mitigate N loss risk in winter wheat production Steffen Rothardt · Henning Kage Received: 25 July 2023 / Accepted: 21 December 2023 / Published online: 9 January 2024 © The Author(s) 2024 Abstract Understanding the interactions between nitrogen mineralization in soil and site-specific environmental factors is essential for developing tailored nitrogen management approaches in intensive agricultural systems. This study assesses the potential of residue management strategies to mitigate nitrogen leaching losses, focusing specifically on winter wheat following winter oilseed rape as a commonly practiced crop sequence in Germany with a high risk of N losses during the percolation period (August–March). Special attention has been given to the interactions of the proposed measures with extreme weather conditions that may become more frequent due to climate change. A well-established plant-soil process model implemented in the HUME modeling environment was used to evaluate the effects of incorporating, removing, or replacing oilseed rape residues with winter wheat straw at 10 sites over 25 years. Results highlight that precipitation exerts a greater influence on nitrogen leaching than local soil properties across the selected study sites. Winter wheat straw Supplementary Information The online version contains supplementary material available at https://doi. org/10.1007/s10705-023-10331-8. S. Rothardt (*) · H. Kage Agronomy and Crop Science Group, Institute of Crop Science and Plant Breeding, Christian-AlbrechtsUniversity, Hermann‑Rodewald‑Str. 9, 24118 Kiel, Germany e-mail: incorporation reduced total net nitrogen mineralization during fall by an average of 12 kg N ha−1 compared to the common practice of keeping the preceding crop residues. Surprisingly, the treatment effects on nitrogen leaching losses fall short of the expectation of a site-specific significant reduction. Most of the initial excess nitrogen remains in the upper layers of the soil profile accessible to wheat roots during the growth period, even in years of exceptional percolation. Nitrogen limitation due to persistent immobilization after winter wheat straw incorporation could not be effectively compensated, resulting in negative yield effects of about 11 ± 5 kg N ha−1. However, this treatment reduced the nitrogen surplus after spring droughts on average by 9.6 ± 4 kg N h a−1. Also, considering a farmer’s perspective, where the potential improvement in nitrogen efficiency must outweigh the additional costs of labor and machinery required to remove or replace residues, the results indicate that retaining the preceding crop residues is currently the most effective approach to mitigate nitrogen losses. Additionally, the study underscores the significance of accounting for site-specific and management-induced mineralization when estimating fertilizer demand to optimize agronomic productivity while minimizing the risk of nutrient losses through leaching. Vol.: (0123456789) 13 54 Introduction In the last few decades, climate change has been significantly impacting our environment, prompting us to address various aspects of human livelihood. Hereby, agriculture is one of the main drivers of the man-made contribution to global warming by direct and indirect greenhouse gas (GHG) emissions (Eyring et al. 2021). Despite the currently high agricultural productivity in Central Europe and especially in Germany, there are certain combinations of crop rotations and environmental conditions that carry the risk of high nitrogen losses. Of particular relevance for the development of the global climate are direct N2O emissions from soil nitrogen turnover as well as indirect emissions after nitrogen lost through leaching or erosion (Canadell et al. 2021; Bijay-Singh and Craswell 2021). A commonly practiced crop rotation in Germany that poses these risks is winter oilseed rape (WOSR) followed by winter wheat (WW). WOSR, as a crop with high N demand (typically fertilized at about 180 kg N ha−1) but rather low nitrogen use efficiency (NUE), often leaves high levels of soil mineral N after harvest (Dreccer et al. 2000; Ziesemer and Lehmann 2006; Bouchet et al. 2016), because N uptake stops relatively early and crop residues of WOSR are not as efficient in immobilizing mineralized soil N than cereal straw. This N supply is usually hardly used by the following winter wheat, with a pre-winter N uptake of approx. 20–30 kg N ha−1 (Henke et al. 2008). Together with N from crop residues and the stabilized organic matter mineralized in fall, this creates a high risk of N loss through leaching during the usually precipitation-rich fall and winter (Webb et al. 2000; Sieling and Kage 2006; Rathke et al. 2006). Extreme weather events that are becoming more frequent as a result of climate change can increase these losses (Ranasinghe et al. 2021; Seneviratne et al. 2021). Unusual heavy rainfall in fall/winter, for example, increases the amount of percolation water and therefore absolute N leaching (Di and Cameron 2002; Zhou and Butterbach-Bahl 2014). On the other hand, persistently high soil moisture (up to saturation) can also lead to oxygen depletion and thus increased denitrification, which would counteract N mineralization and reduce both mineral N and probably the N concentration in the percolation water. Unfortunately, this would be Vol:. (1234567890) 13 Nutr Cycl Agroecosyst (2024) 128:53–71 accompanied by higher N2 and N2O losses. Anoxic conditions could be further intensified by the oxygen-sapping degradation of the introduced biomass. Climate models also predict an increase of spring and summer droughts in central Europe (Jacob et al. 2014). Dry conditions in semi-arid arable soils at times of the major N uptake hampers N supply from the soil, especially when mainly mineral N fertilizer is applied (Ullah et al. 2020). Therefore, N uptake by the crop is reduced. As a result, unused mineral N remains in the soil and is at risk of being lost during the next percolation period. Although predictions differ in frequency, duration and timing of these events (Kunz et al. 2017), a strong impact on agricultural productivity is to be expected (Bönecke et al. 2020). Some regional models even conclude that drought periods are likely to be followed by increased precipitation later in the year (Kunz et al. 2017), which in return induce again enhanced leaching. Although, some crops may even benefit from rising temperatures and increased CO2 concentrations (Shaheen et al. 2022; Wang et al. 2023), the IPCC Sixth Assessment Report highlights the need for changes in land use practices and agricultural management techniques to reduce greenhouse gas emissions and mitigate the impacts of climate change on agricultural systems (IPCC 2021). A lever for change is the management of crop residues a (...truncated)