| 29 Jan 2026
Non-inversion tillage benefits soil N retention during bare soil period coinciding with wet spell
Abstract. Recent meta-analyses suggest risks of increased nitrate leaching with the implementation of reduced tillage practices. This study aimed to quantify effects of a subsidized and commonly implemented form of non-inversion tillage in Switzerland (NIT, i.e. chisel ploughing) in comparison to conventional tillage (CT, i.e. mouldboard ploughing) on nitrate leaching and its driving processes (i.e. water fluxes, soil temperature, plant uptake). A lysimeter experiment was conducted at the lysimeter facility Reckenholz/Zurich in Switzerland, mimicking tillage differences. Results after three years of treatment implementation show that during the following three years, cumulative nitrate leaching was 26 % higher under CT than under NIT (i.e. 63 ± 10 kg/ha N with CT vs. 46 ± 9 kg/ha N with NIT). The observed effect was driven by differences in nitrate concentrations in seepage water rather than seepage water amounts. The beneficial effect of NIT on nitrate leaching was most pronounced during and shortly after a bare soil period following sugar beet cultivation, which coincided with above-average spring precipitation. These findings suggest that reduced soil management may hold the potential to reduce nitrate leaching during winter and spring wet spells with poor plant cover, which are expected to become more frequent with progressing climate change.
General comments
This manuscript evaluates the effect of non-inversion tillage on nitrate leaching in soil. This is, in my opinion, a relevant and original topic. The manuscript is concise and well written, and the study behind it was conducted throughout a good timespan. My main concern is related to the statistical analysis which, in my opinion, should be extended and deepened to support (or disprove) some of the conclusions. In addition to this, I understand that the main focus was given to the effect of treatments on nitrate leaching. However, and considering the importance of yield to farmers, I think that the focus that was given to yield should be increased throughout the manuscript. I include my specific comments below.
Specific comments
Methods: In my opinion, a subsection regarding data analysis or statistical analysis should be added at the end of the Methods section.
Results: The comparisons between treatments should be supported by statistical analysis such as t-tests or their non-parametric equivalents. Yield should be given more relevance throughout the paper, considering its importance to the farmer. In addition to this, I believe that a PCA or correlation analysis may reveal more information from the data.
Discussion: Similarly to what I have referred about the results, the effects of treatments on yield should be given a higher weight.
L80: ETa equation is shown. However, it is not mentioned in the text.
L88: Do the authors have information regarding soil sampling depth?
L119-120: A diagram representing the distribution of crop rotations and cover crops throughout the time of the experiment would increase the clarity of the explanation.
L141-142: This information should be included in the aforementioned subsection about data analysis.
L145-146: This should be checked by a statistical approach such as a t-test or a non-parametric alternative.
L145: Please indicate the Figure/Table where the cummulative ETa is shown.
L146-147: Please add here the reference to the Figure where the yield results are presented. If I am not mistakened, it is Figure F.1 (Appendix F). Maybe transfer it to the main results? In any case, the possible differences between treatments should be confirmed (or disproved) by a statistical analysis. Information about the number of replicates per treatment should be added in the legend of this (similarly to what the authors did in the legend of Figure 3).
L147: Please see my comment about the need for significant differences to be checked by statistical analysis.
L157-159: The authors stated that “nitrate concentrations were significantly higher in CT than NT”. Is this confirmed by a statistical analysis? If so, please show that information in a Figure or Table or refer to one where that information is shown.
L165-167: In my opinion, this hypothesis (and others that the authors find appropriate) should be included at the end of the Introduction. If the authors did not find this appropriate, the sentence should be re-written.
L200-202: Authors claimed that ”Results presented in this study are generally in line with Li et al. (2023), who concluded (...) that the benefits of reduced tillage for nitrate leaching reduction tend to be higher on soils with medium texture and SOC contents >1% in temperate climate zones and with longer durations of reduced tillage practices”. In my opinion, this is not accurate as the authors did not compare different soil textures, different SOC levels or different climate zones.
L221-223: The authors referred that “nitrate leaching was not significantly higher under CT than NIT during days directly after tillage, but only after the termination of sugar beet in 2014”, which seems to indicate that a statistical test (such as a t-test or Mann-Whitney test) was used. However, if I am not mistaken, the results of such test are not shown in the paper.
L249-257: The authors discuss the relationship between SOC and nitrate leaching. This is an interesting relationship which, however, was not tested. Do the authors have data available regarding the SOC content of the studied soils? If so, maybe a relationship between SOC and N leaching could be tested.
L265-289: In subsection 4.3 (Unresolved links), the authors discuss different knowledge gaps regarding the approached subject that exist in literature. In my opinion, the limitations and strengths of their present study should also be approached in this or in other subsection. This could also include suggestions for future work on this subject.
Technical corrections
L115-118: Scientific names should be written in italic.
Throughout the manuscript, nitrate is identified as NO3. I would suggest using its correct chemical formula (NO3-). In some places, it is also identified by its name (nitrate). Therefore, I would also suggest to homogenise this either by identifying it by its name or by its formula.
L159: The non-inversion tillage treatment is identified as NIT throughout the manuscript. However, here and in some other places it is identified as NT.