Effect of crop residue incorporation on soil organic carbon and greenhouse gas emissions in European agricultural soils / Lehtinen T.; Schlatter N.; Baumgarten A.; Bechini L.; Krüger J.; Grignani C.; Zavattaro L.; Costamagna C.; Spiegel H.;. -In: SOIL USE AND MANAGEMENT. -ISSN 0266-0032. -STAMPA. -30(2014), pp. 524-538. Original Citation:Effect of crop residue incorporation on soil organic carbon and greenhouse gas emissions in European agricultural soils Published version:DOI:10.1111/sum.12151 Terms of use:Open Access (Article begins on next page) Anyone can freely access the full text of works made available as "Open Access". Works made available under a Creative Commons license can be used according to the terms and conditions of said license. Use of all other works requires consent of the right holder (author or publisher) if not exempted from copyright protection by the applicable law. intensive cropping systems. Incorporation of crop residues (CR) may be a sustainable 32 management practice to maintain the SOC levels and to increase soil fertility. This study 33 quantifies the effects of CR incorporation on SOC and greenhouse gas (GHG) emissions (CO2 and 34 N2O) in Europe using data from long-term experiments. Response ratios (RRs) for SOC and GHG 35 emissions were calculated between CR incorporation and removal. The influences of 36 environmental zones (ENZs), clay content and experiment duration on the RRs were 37 investigated. We also studied how RRs of SOC and crop yields were correlated. A total of 718 RRs 38 were derived from 39 publications. The SOC increased by 7 % following CR incorporation. In 39 contrast, in a subsample of cases, CO2 emissions were six times and N2O emissions 12 times 40 higher following CR incorporation. The ENZ had no significant influence on RRs. For SOC 41 concentration, soils with a clay content >35 % showed 8 % higher RRs compared to soils with 42 clay contents between 18 and 35 %. As the experiment progressed, RR for SOC concentration 43 and stock increased. For N2O emissions, RR was significantly higher in experiments with a 44 duration <5 years compared to 11-20 years. No significant correlations were found between RR 45 for SOC concentration and yields, but differences between sites and study durations were 46 detected. We suggest a win-win scenario to be crop residue incorporation for a long duration in 47 a continental climate, whereas the worst-case scenario involves crop residue incorporation over 48 the short term in the Mediterranean, especially with vegetative material. We conclude that CR 49 incorporation is important for maintaining SOC, but its influence on GHG emissions should be 50 taken into account as well. 51 52 Availability: This is the author's manuscript

Alternative management practices such as no‐tillage compared to conventional tillage are expected to recover or increase soil quality and productivity, even though all of these aspects are rarely studied together. Long‐term field experiments (LTEs) enable analysis of alternative management practices over time. This study investigated a total of 251 European LTEs in which alternative management practices such as crop rotation, catch crops, cover crops/green manure, no‐tillage, non‐inversion tillage and organic fertilization were applied. Response ratios of indicators for soil quality, climate change and productivity between alternative and reference management practices were derived from a total of 260 publications. Both positive and negative effects of alternative management practices on the different indicators were shown and, as expected, no alternative management practice could comply with all objectives simultaneously. Productivity was hampered by non‐inversion tillage, FYM amendments and incorporation of crop residues. SOC contents were increased significantly following organic fertilizers and non‐inversion tillage. GHG emissions were increased by slurry application and incorporation of crop residues. Our study showed that alternative management practices beneficial to one group of indicators (e.g. organic fertilizers for biological soil quality indicators) are not necessarily beneficial to other indicators (e.g. increase of crop yields). We conclude that LTEs are valuable for finding ways forward in protecting European soils as well as finding evidence‐based alternative management practices for the future; however, experiments should focus more on biological soil quality indicators as well as GHG emissions to enable better evaluation of trade‐offs and mutual benefits of management practices.

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Recent studies show that a labile soil carbon (C) fraction determined with potassium permanganate (KMnO 4 ) reflects the type of soil management. The present study combines the method for determining the active C (AC) pool with an alternative titration of the 0.02 M KMnO 4 solution with sodium oxalate (Na 2 C 2 O 4 ) for routine laboratory analyses. Three long-term field experiments investigated: (i) different cropping systems and 14 C-labelled organic amendments, (ii) three different tillage systems, and (iii) the application of four different kinds of compost. The results showed the depletion of AC in the permanent bare-fallow system of the 14 C-labelled field experiment. When calculating the ratio AC/total organic C (TOC), the depletion of the AC/TOC curve reflected a priming effect, in accord with previous work. We obtained significant positive correlations of AC with TOC, total nitrogen (N t ), humic acid-C and remaining 14 C-labelled material. The AC in the tillage systems experiment was significantly (P < 0.05) different between all three tillage treatments at 0-10 cm depth, and the ratio AC/TOC also revealed a significant difference between minimum and conventional tillage treatments at 10-20 cm. For the compost field experiment, significant differences occurred between plots fertilised solely with N and plots receiving organic amendments. The AC/TOC ratio of the sewage sludge amendment was significantly lower than in all other systems. Correlations of AC with TOC for all samples of the different long-term field experiments revealed different behaviours in different soil types. The correlations of AC with N t showed higher coefficients than with TOC. The applied methodology has a potential for sensitive and reliable detections of differences in soil organic matter characteristics.

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