Pub Date : 2026-01-16DOI: 10.1016/j.still.2026.107070
Ryan D. Stewart, Caroline C. Wolcott
The resilience of subsurface microbial communities to stressors such as drought is an important aspect of healthy and well-functioning soils. The short-term carbon mineralization test (STCM) was developed to quantify the initial flux of carbon dioxide that is produced when soils are dried and then rapidly rewetted. This method is increasingly being adopted as a biological measure of soil health, yet there has been little consideration of how the drying procedure affects results. In this study, we compared STCM results for soil samples that were oven dried for 2–3 d versus air dried for 21 d. The samples came from a research farm in Virginia, United States, and represented four distinct management practices, two sampling depths, and three sampling dates. Oven-drying the samples tended to produce greater STCM values, and factors such as soil management did not significantly modify the correlation between drying procedures. An analysis of the relative differences between oven- and air-dried values showed that air-drying tended to produce greater fluxes in soils with limited carbon resources (i.e., low STCM values), whereas the opposite trend was observed in samples with greater carbon resources (i.e., high STCM values). By imposing elevated temperatures (e.g., 55 °C) and rapid drying, oven conditions appear to emphasize shifts in microbial resource allocation and functioning that occur under stress, and therefore may be preferable when using STCM assays for soil health assessment.
{"title":"Evaluating how drying conditions influence short-term carbon mineralization assays for soil health assessment","authors":"Ryan D. Stewart, Caroline C. Wolcott","doi":"10.1016/j.still.2026.107070","DOIUrl":"10.1016/j.still.2026.107070","url":null,"abstract":"<div><div>The resilience of subsurface microbial communities to stressors such as drought is an important aspect of healthy and well-functioning soils. The short-term carbon mineralization test (STCM) was developed to quantify the initial flux of carbon dioxide that is produced when soils are dried and then rapidly rewetted. This method is increasingly being adopted as a biological measure of soil health, yet there has been little consideration of how the drying procedure affects results. In this study, we compared STCM results for soil samples that were oven dried for 2–3 d versus air dried for 21 d. The samples came from a research farm in Virginia, United States, and represented four distinct management practices, two sampling depths, and three sampling dates. Oven-drying the samples tended to produce greater STCM values, and factors such as soil management did not significantly modify the correlation between drying procedures. An analysis of the relative differences between oven- and air-dried values showed that air-drying tended to produce greater fluxes in soils with limited carbon resources (i.e., low STCM values), whereas the opposite trend was observed in samples with greater carbon resources (i.e., high STCM values). By imposing elevated temperatures (e.g., 55 °C) and rapid drying, oven conditions appear to emphasize shifts in microbial resource allocation and functioning that occur under stress, and therefore may be preferable when using STCM assays for soil health assessment.</div></div>","PeriodicalId":49503,"journal":{"name":"Soil & Tillage Research","volume":"259 ","pages":"Article 107070"},"PeriodicalIF":6.8,"publicationDate":"2026-01-16","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145980650","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":1,"RegionCategory":"农林科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2026-01-16DOI: 10.1016/j.still.2025.107052
Mark A. Stalham , Shaunagh Slack , Ryan Barrett , Ranjan Bhattacharyya , Karina M.V. Cavalieri-Polizeli , Rosario Fuentes del Río , Iain Kirkwood , John E. McPhee , Simon McWilliam , Mark J. Pavek , Mehdi Rahmati , Lautaro Rios , Kirstie Speed , Martin Steyn , Mike Thornton , Lucy Tillier , Barry White , Philip Wright , Ying Zhao , Blair M. McKenzie
Papers on potato cultivation experiments rarely provide detailed information about the type and number of cultivation operations used. There is a need to document best practice for cultivating soil for potato production. A global survey was conducted to document the types, frequency and depths of cultivation systems used for potato production in different regions, and to identify representative cultivation sequences used in current commercial practice. Analysis of 65 survey responses representing the major global production areas found that, compared with the literature, cultivation intensity, depth and number of operations were generally greater than necessary for seedbed preparation. Deep non-inversion and inversion techniques for primary cultivations were frequently succeeded by powered, high-intensity rotary equipment. Tubers accounted for only 2–7 % of the total soil volume in the ridge, yet the large cross-sectional area of the planted ridges was adequate for containing high tuber yields without causing greening. Yields reported by growers were generally not correlated with intensity or number of cultivation operations or the size of ridges produced. Additionally, none of the surveyed growers practiced minimum or reduced tillage. This suggests there are opportunities to reduce the number of cultivation operations in potato production, potentially minimising soil disturbance and providing benefits such as improved soil quality, reduced greenhouse gas emissions (both from fuel and gaseous losses from soils during cultivation), lower machinery wear and a smaller carbon footprint.
{"title":"Soil cultivation for potatoes. A global survey of cultivation practices","authors":"Mark A. Stalham , Shaunagh Slack , Ryan Barrett , Ranjan Bhattacharyya , Karina M.V. Cavalieri-Polizeli , Rosario Fuentes del Río , Iain Kirkwood , John E. McPhee , Simon McWilliam , Mark J. Pavek , Mehdi Rahmati , Lautaro Rios , Kirstie Speed , Martin Steyn , Mike Thornton , Lucy Tillier , Barry White , Philip Wright , Ying Zhao , Blair M. McKenzie","doi":"10.1016/j.still.2025.107052","DOIUrl":"10.1016/j.still.2025.107052","url":null,"abstract":"<div><div>Papers on potato cultivation experiments rarely provide detailed information about the type and number of cultivation operations used. There is a need to document best practice for cultivating soil for potato production. A global survey was conducted to document the types, frequency and depths of cultivation systems used for potato production in different regions, and to identify representative cultivation sequences used in current commercial practice. Analysis of 65 survey responses representing the major global production areas found that, compared with the literature, cultivation intensity, depth and number of operations were generally greater than necessary for seedbed preparation. Deep non-inversion and inversion techniques for primary cultivations were frequently succeeded by powered, high-intensity rotary equipment. Tubers accounted for only 2–7 % of the total soil volume in the ridge, yet the large cross-sectional area of the planted ridges was adequate for containing high tuber yields without causing greening. Yields reported by growers were generally not correlated with intensity or number of cultivation operations or the size of ridges produced. Additionally, none of the surveyed growers practiced minimum or reduced tillage. This suggests there are opportunities to reduce the number of cultivation operations in potato production, potentially minimising soil disturbance and providing benefits such as improved soil quality, reduced greenhouse gas emissions (both from fuel and gaseous losses from soils during cultivation), lower machinery wear and a smaller carbon footprint.</div></div>","PeriodicalId":49503,"journal":{"name":"Soil & Tillage Research","volume":"259 ","pages":"Article 107052"},"PeriodicalIF":6.8,"publicationDate":"2026-01-16","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145980566","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":1,"RegionCategory":"农林科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2026-01-16DOI: 10.1016/j.still.2026.107072
Shiqi Xu , Zengming Chen , Nan Zhang , Ye Li , Yehong Xu , Weixin Ding
The responses of soil respiration (Rs) and its heterotrophic (Rh) and autotrophic (Ra) components to straw return remain equivocal, with microbial-enzymatic mechanisms under co-applied nitrogen (N) fertilization poorly characterized, limiting rational straw and N managements for soil carbon (C) sequestration in agroecosystems. Here, we quantified annual fluxes of Rs, Rh, and Ra in paired northeast China croplands with equivalent soil organic C quantity but distinct C quality (high vs. low: HCQ vs. LCQ), under four treatments: no N fertilization/straw return (Control), N fertilization-only (NF), straw return-only (SR), and co-applications (SRF). Annual Rs emissions were consistently higher in HCQ than in LCQ soils, primarily driven by Rh elevation from greater substrate C bioavailability. Crucially, N fertilization induced C quality-dependent divergence: suppressing Rs in HCQ soils through stoichiometric constraints that diverted C flux from Rh to microbial assimilation, while maintaining negligible impacts in LCQ soils due to persistent microbial N mining rather than metabolic suppression. Straw return universally stimulated Rs (26–31 %) via hydrolytic enzyme-mediated Rh amplification following C amendments. Notably, HCQ soils exhibited significantly faster straw-induced mineralization than LCQ soils (75 % vs. 43 % efficiency), attributed to HCQ’s superior fungal-oxidase capacity targeting recalcitrant C. Regarding interactive effects, N fertilization dampened straw-induced Rh in HCQ by diverting residue-C from CO2 release to stabilization, reducing mineralization efficiency to 16 %, whereas in LCQ, SRF maintained Rh at SR levels under persistent substrate constraints. Conversely, Ra consistently depended on N supplementation, mechanistically evidenced by increased plant biomass and chlorophyll content. Under straw return and N fertilization interactions, annual Ra increased only in LCQ soils, consistent with improved mineral N availability and plant N status, enhancing belowground C allocation, whereas HCQ showed little Ra response. Collectively, our findings establish soil C quality as the pivotal regulator dictating microbe-plant resource partitioning. Precision management must implement C quality-stratified straw and N coordination to synchronize climate mitigation with sustainable productivity.
土壤呼吸（Rs）及其异养（Rh）和自养（Ra）组分对秸秆还田的响应尚不明确，氮肥共施下的微生物-酶机制尚不清楚，限制了合理的秸秆和氮肥管理对农业生态系统土壤碳(C)固存的影响。本研究量化了东北土壤有机碳量相当但碳质量不同（高与低：HCQ与LCQ）的配对农田，在不施氮/秸秆还田（对照）、只施氮（NF）、只施秸秆还田（SR）和共施（SRF） 4种处理下，Rs、Rh和Ra的年通量。HCQ土壤的年Rs排放量始终高于LCQ土壤，这主要是由于更高的底物C生物利用度导致Rh升高所致。至关重要的是，氮肥诱导了C质量依赖的差异：通过化学计量限制，将C通量从Rh转移到微生物同化，从而抑制高碳土壤中的Rs，而在低碳土壤中，由于微生物持续的N挖掘而不是代谢抑制，其影响可以忽略不计。秸秆返回通过水解酶介导的Rh扩增在C修改后普遍刺激Rs（26-31 %）。值得注意的是，HCQ土壤的秸秆诱导矿化速度明显快于LCQ土壤（75% % vs. 43% %），这是由于HCQ具有更强的针对顽固性c的真菌氧化酶能力。在相互作用方面，氮肥通过将残余c从CO2释放转移到稳定状态来抑制HCQ中秸秆诱导的Rh，将矿化效率降低至16% %，而在LCQ中，SRF在持续的底物约束下将Rh维持在SR水平。相反，Ra持续依赖于N的补充，其机理表现为植物生物量和叶绿素含量的增加。在秸秆还田和氮肥交互作用下，年Ra仅在低智商土壤中增加，这与改善矿质氮有效性和植物氮状态，促进地下碳分配一致，而高智商土壤对Ra的响应较小。总的来说，我们的研究结果确定土壤C质量是决定微生物-植物资源分配的关键调节因子。精准管理必须实施碳质量分层秸秆和氮协调，使气候减缓与可持续生产力同步。
{"title":"Soil carbon quality determined the responses of respiration components to nitrogen fertilization and straw return","authors":"Shiqi Xu , Zengming Chen , Nan Zhang , Ye Li , Yehong Xu , Weixin Ding","doi":"10.1016/j.still.2026.107072","DOIUrl":"10.1016/j.still.2026.107072","url":null,"abstract":"<div><div>The responses of soil respiration (Rs) and its heterotrophic (Rh) and autotrophic (Ra) components to straw return remain equivocal, with microbial-enzymatic mechanisms under co-applied nitrogen (N) fertilization poorly characterized, limiting rational straw and N managements for soil carbon (C) sequestration in agroecosystems. Here, we quantified annual fluxes of Rs, Rh, and Ra in paired northeast China croplands with equivalent soil organic C quantity but distinct C quality (high vs. low: HCQ vs. LCQ), under four treatments: no N fertilization/straw return (Control), N fertilization-only (NF), straw return-only (SR), and co-applications (SRF). Annual Rs emissions were consistently higher in HCQ than in LCQ soils, primarily driven by Rh elevation from greater substrate C bioavailability. Crucially, N fertilization induced C quality-dependent divergence: suppressing Rs in HCQ soils through stoichiometric constraints that diverted C flux from Rh to microbial assimilation, while maintaining negligible impacts in LCQ soils due to persistent microbial N mining rather than metabolic suppression. Straw return universally stimulated Rs (26–31 %) via hydrolytic enzyme-mediated Rh amplification following C amendments. Notably, HCQ soils exhibited significantly faster straw-induced mineralization than LCQ soils (75 % vs. 43 % efficiency), attributed to HCQ’s superior fungal-oxidase capacity targeting recalcitrant C. Regarding interactive effects, N fertilization dampened straw-induced Rh in HCQ by diverting residue-C from CO<sub>2</sub> release to stabilization, reducing mineralization efficiency to 16 %, whereas in LCQ, SRF maintained Rh at SR levels under persistent substrate constraints. Conversely, Ra consistently depended on N supplementation, mechanistically evidenced by increased plant biomass and chlorophyll content. Under straw return and N fertilization interactions, annual Ra increased only in LCQ soils, consistent with improved mineral N availability and plant N status, enhancing belowground C allocation, whereas HCQ showed little Ra response. Collectively, our findings establish soil C quality as the pivotal regulator dictating microbe-plant resource partitioning. Precision management must implement C quality-stratified straw and N coordination to synchronize climate mitigation with sustainable productivity.</div></div>","PeriodicalId":49503,"journal":{"name":"Soil & Tillage Research","volume":"259 ","pages":"Article 107072"},"PeriodicalIF":6.8,"publicationDate":"2026-01-16","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145980652","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":1,"RegionCategory":"农林科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2026-01-15DOI: 10.1016/j.still.2026.107067
Sissel Hansen , Synnøve Rivedal , Samson Øpstad , Johannes Deelstra , Trond Børresen , Torfinn Torp , Peter Dörsch
To study the effect of drainage intensity on GHG emissions and N drainage losses in cool-humid Norway, we established drainage systems with 6 and 12 m drain spacing in a previously undrained sandy loam (Mollic gleysol) collecting data in the years 2014–2016. After sowing a mixed grass ley, subsurface drainage was larger (1271 versus 699 mm) and mean ground water table (GWT) lower (102 versus 79 cm) with 6 than with 12 m drain spacing. Water filled pore space (WFPS) remained high throughout most of the year (> 80 %). It was highest in 12 m drain spacing, but shortly after fertilizations no differences between the two drainage systems were found. N2O emissions after fertilization were larger in the 12 m system than in the 6 m system. Cumulative N2O emissions in the 6 and 12 m system were 4.0 versus 2.5 kg N ha−2 yr−1. N leaching for the entire observation period (29 months) was larger in the 6 m (42 kg ha−1) than the 12 m (19 kg ha−1) system. Grass yields, plant N-recovery and fertilizer N use efficiency was larger with 6 than 12 m. The mean N2O emission factor was significantly higher with 6 than with 12 m drain spacing (1.4 versus 0.8 % N2O-N of N applied). The 6 m system acted as a net sink for CH4, whereas the 12 m system was a net CH4 source and had a higher climate forcing than the 12 m system (1390 versus 1110 g CO2 eq. m−2 yr−1), but scaled for grass dry matter yield the climate forcing was similar. We conclude that larger N2O emissions with 6 m drain spacing were likely due to a combination of less complete denitrification and a naturally higher SOM content at this site, releasing extra mineral N. Our study can therefore not confirm that increased drainage intensity intrinsically reduces N2O emissions from crop production in cool-humid climates.
为了研究排水强度对凉爽潮湿的挪威温室气体排放和氮排放损失的影响，我们在2014-2016年收集数据，在先前未排水的砂壤土（Mollic gleysol）中建立了排水间距为6和12 m的排水系统。播种混合草地后，排水间距为6 m比12 m时地下排水更大（1271 vs 699 mm），平均地下水位（GWT）更低（102 vs 79 cm）。水填充孔隙空间（WFPS）在一年中大部分时间保持在较高水平（> 80 %）。排水间距为12 m时最高，但施肥后不久，两种排水系统之间没有发现差异。施肥后12 m体系的N2O排放量大于6 m体系。6和12 m系统的累积N2O排放量分别为4.0和2.5 kg N ha−2 yr−1。在整个观察期内（29个月），6 m（42 kg ha−1）体系的氮淋失量大于12 m（19 kg ha−1）体系。产草量、植株氮素恢复率和氮肥利用率均大于6 ~ 12 m。排水间距为6 m时，N2O的平均排放因子显著高于排水间距为12 m时（分别为1.4和0.8 % N2O-N）。6 m系统是CH4的净汇，而12 m系统是CH4的净源，并且比12 m系统具有更高的气候强迫（1390对1110 g CO2当量m−2年−1），但按草干物质产量比例计算，气候强迫是相似的。我们得出的结论是，排水间距为6 m的N2O排放量较大，可能是由于该地点的反硝化不完全和天然较高的SOM含量的结合，释放了额外的矿物质n。因此，我们的研究不能证实在凉爽潮湿的气候下，排水强度的增加本质上减少了作物生产的N2O排放。
{"title":"Impact of drain spacing on subsurface drainage and greenhouse gas fluxes in a grassland on a Mollic gleysol in western Norway","authors":"Sissel Hansen , Synnøve Rivedal , Samson Øpstad , Johannes Deelstra , Trond Børresen , Torfinn Torp , Peter Dörsch","doi":"10.1016/j.still.2026.107067","DOIUrl":"10.1016/j.still.2026.107067","url":null,"abstract":"<div><div>To study the effect of drainage intensity on GHG emissions and N drainage losses in cool-humid Norway, we established drainage systems with 6 and 12 m drain spacing in a previously undrained sandy loam (Mollic gleysol) collecting data in the years 2014–2016. After sowing a mixed grass ley, subsurface drainage was larger (1271 versus 699 mm) and mean ground water table (GWT) lower (102 versus 79 cm) with 6 than with 12 m drain spacing. Water filled pore space (WFPS) remained high throughout most of the year (> 80 %). It was highest in 12 m drain spacing, but shortly after fertilizations no differences between the two drainage systems were found. N<sub>2</sub>O emissions after fertilization were larger in the 12 m system than in the 6 m system. Cumulative N<sub>2</sub>O emissions in the 6 and 12 m system were 4.0 versus 2.5 kg N ha<sup>−2</sup> yr<sup>−1</sup>. N leaching for the entire observation period (29 months) was larger in the 6 m (42 kg ha<sup>−1</sup>) than the 12 m (19 kg ha<sup>−1</sup>) system<em>.</em> Grass yields, plant N-recovery and fertilizer N use efficiency was larger with 6 than 12 m. The mean N<sub>2</sub>O emission factor was significantly higher with 6 than with 12 m drain spacing (1.4 versus 0.8 % N<sub>2</sub>O-N of N applied). The 6 m system acted as a net sink for CH<sub>4</sub>, whereas the 12 m system was a net CH<sub>4</sub> source and had a higher climate forcing than the 12 m system (1390 versus 1110 g CO<sub>2</sub> eq. m<sup>−2</sup> yr<sup>−1</sup>), but scaled for grass dry matter yield the climate forcing was similar. We conclude that larger N<sub>2</sub>O emissions with 6 m drain spacing were likely due to a combination of less complete denitrification and a naturally higher SOM content at this site, releasing extra mineral N. Our study can therefore not confirm that increased drainage intensity intrinsically reduces N<sub>2</sub>O emissions from crop production in cool-humid climates.</div></div>","PeriodicalId":49503,"journal":{"name":"Soil & Tillage Research","volume":"259 ","pages":"Article 107067"},"PeriodicalIF":6.8,"publicationDate":"2026-01-15","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145980514","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":1,"RegionCategory":"农林科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2026-01-13DOI: 10.1016/j.still.2026.107068
Fengnian Zhao , Lei Zhang , Xin Zhao , Yucai Xie , Yuanhang Guo , Weixiong Huang , Hongbo Wang , Xingpeng Wang , Yang Gao
With growing concerns about global warming, balancing cotton yield and greenhouse gas emissions is crucial for sustainable agricultural production. While deficit irrigation and nitrogen fertilizer reduction have been proven effective strategies in improving irrigation water productivity and nitrogen use efficiency in Xinjiang, their impacts on carbon footprint and ecological-economic benefits of cotton remains unclear. To quantify the effects of irrigation and nitrogen application on soil carbon emissions and ecological environment in cotton fields, a two-year field experiment was conducted in the Tarim River Basin from 2022 to 2023. The study monitored greenhouse gas emissions, cotton yield, carbon footprint, and ecological-economic benefit under two irrigation quotas (W1: 45 mm deficit irrigation, W2: 54 mm full irrigation) and three nitrogen fertilizer levels (F1: 150 kg ha−1 with a 50 % nitrogen reduction, F2: 225 kg ha−1 with a 75 % nitrogen reduction, F3: 300 kg ha−1 conventional application). Results showed that increasing irrigation and nitrogen application significantly raised soil CO2 and N2O emissions by 79.75–340.43 kg CO2-C ha−1 and by 0.17–0.46 kg N2O-N ha−1, respectively, while reducing soil CH4 uptake by 0.03–0.08 kg ha−1(P < 0.01). The W2F2 treatment (54 mm irrigation, 225 kg·ha−1 nitrogen) outperformed the conventional W2F3 treatment, reducing 70.96 kg CO2-C ha−1, 0.21 N2O-N ha−1, 7.48 % carbon footprint, and 14.70 % carbon footprint per unit yield. Additionally, it increased CH4 uptake by 0.02 kg CH4-C ha−1, yield by 8.47 %, irrigation water use productivity by 8.47 %, nitrogen partial factor productivity by 44.23 %, and ecological-economic benefit by 38.81 %. Thus, applying 225 kg ha−1 nitrogen with a 54 mm irrigation quota is an effective strategy to reduce the carbon footprint while improving cotton yield, resource use efficiency, and ecological-economic benefits in filmless drip-irrigated cotton fields in southern Xinjiang.
随着人们对全球变暖的担忧日益加剧，平衡棉花产量和温室气体排放对可持续农业生产至关重要。亏缺灌溉和氮肥减量是提高新疆灌溉水生产力和氮素利用效率的有效策略，但对棉花碳足迹和生态经济效益的影响尚不清楚。为量化灌溉施氮对棉田土壤碳排放和生态环境的影响，于2022 - 2023年在塔里木河流域进行了为期2年的田间试验。研究监测了两种灌溉定额（W1: 45 mm亏缺灌溉、W2: 54 mm全灌）和三种氮肥水平（F1: 150 kg ha - 1，减氮50% %，F2: 225 kg ha - 1，减氮75% %，F3: 300 kg ha - 1常规施用）下的温室气体排放、棉花产量、碳足迹和生态经济效益。结果表明，增加灌溉和施氮量显著提高了土壤CO2和N2O排放量，分别提高了79.75 ~ 340.43 kg CO2- c ha - 1和0.17 ~ 0.46 kg N2O- n ha - 1，减少了0.03 ~ 0.08 kg ha - 1（P <； 0.01）。W2F2处理（灌溉54 mm，施氮225 kg·ha - 1）优于常规W2F3处理，单位产量碳足迹减少70.96 kg CO2-C ha - 1, 0.21 N2O-N ha - 1, 7.48 %和14.70 %。此外，CH4吸收率提高0.02 kg CH4- c ha - 1，产量提高8.47 %，灌溉水利用生产率提高8.47 %，氮偏因子生产率提高44.23 %，生态经济效益提高38.81 %。因此，在南疆无膜滴灌棉田中，施用225 kg ha−1氮肥和54 mm灌溉定额是减少碳足迹、提高棉花产量、资源利用效率和生态经济效益的有效策略。
{"title":"Optimizing irrigation and fertilization strategies to reduce the carbon footprint and enhance ecological-economic benefit in non-film drip-irrigated cotton fields in southern Xinjiang","authors":"Fengnian Zhao , Lei Zhang , Xin Zhao , Yucai Xie , Yuanhang Guo , Weixiong Huang , Hongbo Wang , Xingpeng Wang , Yang Gao","doi":"10.1016/j.still.2026.107068","DOIUrl":"10.1016/j.still.2026.107068","url":null,"abstract":"<div><div>With growing concerns about global warming, balancing cotton yield and greenhouse gas emissions is crucial for sustainable agricultural production. While deficit irrigation and nitrogen fertilizer reduction have been proven effective strategies in improving irrigation water productivity and nitrogen use efficiency in Xinjiang, their impacts on carbon footprint and ecological-economic benefits of cotton remains unclear. To quantify the effects of irrigation and nitrogen application on soil carbon emissions and ecological environment in cotton fields, a two-year field experiment was conducted in the Tarim River Basin from 2022 to 2023. The study monitored greenhouse gas emissions, cotton yield, carbon footprint, and ecological-economic benefit under two irrigation quotas (W1: 45 mm deficit irrigation, W2: 54 mm full irrigation) and three nitrogen fertilizer levels (F1: 150 kg ha<sup>−1</sup> with a 50 % nitrogen reduction, F2: 225 kg ha<sup>−1</sup> with a 75 % nitrogen reduction, F3: 300 kg ha<sup>−1</sup> conventional application). Results showed that increasing irrigation and nitrogen application significantly raised soil CO<sub>2</sub> and N<sub>2</sub>O emissions by 79.75–340.43 kg CO<sub>2</sub>-C ha<sup>−1</sup> and by 0.17–0.46 kg N<sub>2</sub>O-N ha<sup>−1</sup>, respectively, while reducing soil CH<sub>4</sub> uptake by 0.03–0.08 kg ha<sup>−1</sup>(P < 0.01). The W2F2 treatment (54 mm irrigation, 225 kg·ha<sup>−1</sup> nitrogen) outperformed the conventional W2F3 treatment, reducing 70.96 kg CO<sub>2</sub>-C ha<sup>−1</sup>, 0.21 N<sub>2</sub>O-N ha<sup>−1</sup>, 7.48 % carbon footprint, and 14.70 % carbon footprint per unit yield. Additionally, it increased CH<sub>4</sub> uptake by 0.02 kg CH<sub>4</sub>-C ha<sup>−1</sup>, yield by 8.47 %, irrigation water use productivity by 8.47 %, nitrogen partial factor productivity by 44.23 %, and ecological-economic benefit by 38.81 %. Thus, applying 225 kg ha<sup>−1</sup> nitrogen with a 54 mm irrigation quota is an effective strategy to reduce the carbon footprint while improving cotton yield, resource use efficiency, and ecological-economic benefits in filmless drip-irrigated cotton fields in southern Xinjiang.</div></div>","PeriodicalId":49503,"journal":{"name":"Soil & Tillage Research","volume":"259 ","pages":"Article 107068"},"PeriodicalIF":6.8,"publicationDate":"2026-01-13","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145961663","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":1,"RegionCategory":"农林科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Nitrate accumulation in the soil profile is a major fate of surplus nitrogen (N). However, variations in nitrate distribution in deep soil profiles caused by extreme rainfall are not quantified, particularly in intensive agricultural areas with high N surplus. Our objective was to investigate how extreme rainfall events affect nitrate distribution and leaching in intensively managed kiwifruit orchard regions. Soil samples were collected from deep soil profiles (down to 10 m) in three landforms (loess tableland, alluvial plain, and pluvial fan) located in the northern slope region of the Qinling Mountains. Sampling was conducted in two normal rainfall years and following an extreme rainfall year that broke a 60-year rainfall record for the region. In normal rainfall years, the nitrate accumulation within the 0–10 m soil profile at sampling sites was highest in the loess tableland (10,769 kg N ha−1), followed by alluvial plain (8776 kg N ha−1) and pluvial fan (6682 kg N ha−1). After the extreme rainfall event, nitrate accumulation in 0–10 m depth decreased by 46–62 % across all sites (with reductions exceeding 80 % in the 0–2 m depth). The magnitude of reduction among landforms followed the order: pluvial fan > alluvial plain > loess tableland. Extreme rainfall caused the accumulated nitrate peak in the soil profiles to move downwards, 3.6 m in the loess tableland, 3.8 m in the alluvial plain and 4.0 m in the pluvial fan at all sampling sites. This suggests that extreme rainfall promoted the leaching of nitrate into the deeper soil layers. We observed that the sand content was negatively correlated with nitrate accumulation but positively correlated with nitrate leaching in different landforms. These findings highlight that extreme rainfall events can significantly intensify nitrate leaching through the soil profile. Thus, consideration of extreme rainfall is critical when assessing environmental pollution risks and developing management practices to mitigate N losses.
硝态氮在土壤剖面中的积累是氮素过剩的主要原因。然而，极端降雨引起的深层土壤剖面中硝酸盐分布的变化并没有被量化，特别是在高氮剩余的集约农业地区。我们的目的是调查极端降雨事件如何影响集中管理猕猴桃果园地区硝酸盐分布和淋失。在秦岭北坡区黄土塬地、冲积平原和洪积扇3种地形中采集深层土壤剖面（深度≤10 m）土壤样品。采样是在两个正常降雨年份进行的，以及在一个打破该地区60年降雨记录的极端降雨年份之后进行的。在正常降雨年，各样点0 ~ 10 m土壤剖面的硝态氮累积量以黄土高原最高（10,769 kg N ha−1），其次是冲积平原（8776 kg N ha−1）和洪积扇（6682 kg N ha−1）。极端降雨事件发生后，各站点0-10 m深度的硝酸盐累积量减少了46-62 %（0-2 m深度的减少量超过80 %）。各地貌减少幅度依次为：洪积扇>； 冲积平原>； 黄土塬地。极端降雨导致土壤剖面累积硝酸盐峰值下移，各样点黄土塬区为3.6 m，冲积平原为3.8 m，洪积扇为4.0 m。这表明极端降雨促进了硝酸盐渗入更深的土层。研究发现，在不同的地形中，含砂量与硝态氮积累呈负相关，与硝态氮淋溶呈正相关。这些研究结果表明，极端降雨事件可以显著加剧土壤剖面的硝酸盐淋滤。因此，在评估环境污染风险和制定管理措施以减轻氮损失时，考虑极端降雨是至关重要的。
{"title":"Extreme rainfall redistributes and leaches nitrate accumulated in the soil profiles of an intensive agricultural region","authors":"Shimao Wang , Xiaowei Yu , Jianping Fei , Tianyi Zhao , Yucheng Xia , Jingbo Gao , Zhujun Chen , Gurpal S. Toor , Jianbin Zhou","doi":"10.1016/j.still.2026.107063","DOIUrl":"10.1016/j.still.2026.107063","url":null,"abstract":"<div><div>Nitrate accumulation in the soil profile is a major fate of surplus nitrogen (N). However, variations in nitrate distribution in deep soil profiles caused by extreme rainfall are not quantified, particularly in intensive agricultural areas with high N surplus. Our objective was to investigate how extreme rainfall events affect nitrate distribution and leaching in intensively managed kiwifruit orchard regions. Soil samples were collected from deep soil profiles (down to 10 m) in three landforms (loess tableland, alluvial plain, and pluvial fan) located in the northern slope region of the Qinling Mountains. Sampling was conducted in two normal rainfall years and following an extreme rainfall year that broke a 60-year rainfall record for the region. In normal rainfall years, the nitrate accumulation within the 0–10 m soil profile at sampling sites was highest in the loess tableland (10,769 kg N ha<sup>−1</sup>), followed by alluvial plain (8776 kg N ha<sup>−1</sup>) and pluvial fan (6682 kg N ha<sup>−1</sup>). After the extreme rainfall event, nitrate accumulation in 0–10 m depth decreased by 46–62 % across all sites (with reductions exceeding 80 % in the 0–2 m depth). The magnitude of reduction among landforms followed the order: pluvial fan > alluvial plain > loess tableland. Extreme rainfall caused the accumulated nitrate peak in the soil profiles to move downwards, 3.6 m in the loess tableland, 3.8 m in the alluvial plain and 4.0 m in the pluvial fan at all sampling sites. This suggests that extreme rainfall promoted the leaching of nitrate into the deeper soil layers. We observed that the sand content was negatively correlated with nitrate accumulation but positively correlated with nitrate leaching in different landforms. These findings highlight that extreme rainfall events can significantly intensify nitrate leaching through the soil profile. Thus, consideration of extreme rainfall is critical when assessing environmental pollution risks and developing management practices to mitigate N losses.</div></div>","PeriodicalId":49503,"journal":{"name":"Soil & Tillage Research","volume":"259 ","pages":"Article 107063"},"PeriodicalIF":6.8,"publicationDate":"2026-01-13","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145957374","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":1,"RegionCategory":"农林科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2026-01-12DOI: 10.1016/j.still.2026.107069
Kang Li , Dániel Nagy , Thomas Keller , Kornél Tamás
Earthworms play an essential role in maintaining and restoring soil structure through burrowing. Although the importance of earthworms is well recognized, knowledge on penetration forces and energy requirements of burrowing remain limited. To investigate these mechanisms, we preformed measurements and simulations of cone penetration analogues, with cones that had a center hole to mimic soil ingestion by earthworms. Measurements were carried out to analyze soil displacement patterns for various cone characteristics, while discrete element method (DEM) simulations accelerated by graphical processor units (GPUs) were performed to quantify penetration forces and calculate energy requirements for burrowing. The influence of cone half-angle, the center hole diameter that mimic the mouth opening of an earthworm, and lubrication representing earthworm mucus are explored. The main findings show that more pointed cones reduce penetration force and compaction in the axial direction but limit soil ingestion, while blunter cones increase ingestion at the cost of higher penetration energy. Results indicate that cone half-angles of (given a center hole) maximize earthworm burrowing efficiency in the investigated silt loam soil, as in that case available energy from soil ingestion is five-fold the energy requirement of burrowing. Lubrication had little effect in a low organic content silt loam soil while it slightly reduced the required penetration force in a high organic content silt loam soil. Overall, the combination of experiments and DEM simulations offer a mechanistic understanding of soil ingestion of earthworms that was not previously available.
{"title":"Evaluating the effects of earthworm tip geometry on burrowing forces using cone penetration analogues and GPU-based discrete element method (DEM) simulations","authors":"Kang Li , Dániel Nagy , Thomas Keller , Kornél Tamás","doi":"10.1016/j.still.2026.107069","DOIUrl":"10.1016/j.still.2026.107069","url":null,"abstract":"<div><div>Earthworms play an essential role in maintaining and restoring soil structure through burrowing. Although the importance of earthworms is well recognized, knowledge on penetration forces and energy requirements of burrowing remain limited. To investigate these mechanisms, we preformed measurements and simulations of cone penetration analogues, with cones that had a center hole to mimic soil ingestion by earthworms. Measurements were carried out to analyze soil displacement patterns for various cone characteristics, while discrete element method (DEM) simulations accelerated by graphical processor units (GPUs) were performed to quantify penetration forces and calculate energy requirements for burrowing. The influence of cone half-angle, the center hole diameter that mimic the mouth opening of an earthworm, and lubrication representing earthworm mucus are explored. The main findings show that more pointed cones reduce penetration force and compaction in the axial direction but limit soil ingestion, while blunter cones increase ingestion at the cost of higher penetration energy. Results indicate that cone half-angles of <span><math><mrow><mn>2</mn><msup><mrow><mn>5</mn></mrow><mrow><mo>∘</mo></mrow></msup><mtext>–</mtext><mn>3</mn><msup><mrow><mn>0</mn></mrow><mrow><mo>∘</mo></mrow></msup></mrow></math></span> (given a <span><math><mrow><mtext>2</mtext><mspace></mspace><mtext>mm</mtext></mrow></math></span> center hole) maximize earthworm burrowing efficiency in the investigated silt loam soil, as in that case available energy from soil ingestion is five-fold the energy requirement of burrowing. Lubrication had little effect in a low organic content silt loam soil while it slightly reduced the required penetration force in a high organic content silt loam soil. Overall, the combination of experiments and DEM simulations offer a mechanistic understanding of soil ingestion of earthworms that was not previously available.</div></div>","PeriodicalId":49503,"journal":{"name":"Soil & Tillage Research","volume":"259 ","pages":"Article 107069"},"PeriodicalIF":6.8,"publicationDate":"2026-01-12","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145957377","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":1,"RegionCategory":"农林科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2026-01-09DOI: 10.1016/j.still.2026.107059
Lei Ma , Chunmei Wang , Guanghui Zhang , Manuel La Licata , Yanru Wen , Michael Maerker , Qinke Yang , Guowei Pang , Enheng Wang
Gully erosion severely threatens land resources and agricultural sustainability, yet the role of subsurface erosion-resistant soil layers remains poorly understood. This study integrated sub-meter imagery with stratified soil sampling (0–120 cm depth) across 79 gullies with comparable slopes gradient and catchment areas on a farm (570 km2) in the black soil region of northeast China to quantify how erosion-resistant layers control gully sidewall expansion and headcut retreat. Ten soil properties were analyzed to construct a PCA-based comprehensive soil erosion resistance score (CRS), revealing a decline in CRS with profile depth and a hierarchy of soil resistance: Black soil > Black soil-Loess transition layer > Loess > Loess-Sand transition layer > Fluvial sandy. The first two layers were identified as erosion-resistant layers. Through threshold effect analysis, a threshold erosion-resistant layer thickness of 53.88 cm was identified (p < 0.01) for sidewall expansion, revealing a 1.36 cm/yr acceleration in gully sidewall expansion per 1 cm thinning within the threshold thickness. Gullies with erosion-resistant layers below the sensitivity thickness experienced 2.03 times higher expansion rate. Gullies newly formed since 2010 exhibited a lower threshold (34.90 cm) than the pre-existing gullies. Gully headcut retreat rate was 43 % higher if the resistant layer was thinner than 54.28 cm, despite no significant detectable threshold. The threshold erosion-resistant layer thickness is potentially modulated by the depth of soil cracks and needs further investigation. This study highlights the importance of soil-profile features, not just surface properties, in gully erosion research. Integration of this threshold into gully erosion models could revolutionize gully prediction and precision conservation strategies.
{"title":"Threshold effects of resistant-layer thickness on gully development in the black soil region of Northeast China","authors":"Lei Ma , Chunmei Wang , Guanghui Zhang , Manuel La Licata , Yanru Wen , Michael Maerker , Qinke Yang , Guowei Pang , Enheng Wang","doi":"10.1016/j.still.2026.107059","DOIUrl":"10.1016/j.still.2026.107059","url":null,"abstract":"<div><div>Gully erosion severely threatens land resources and agricultural sustainability, yet the role of subsurface erosion-resistant soil layers remains poorly understood. This study integrated sub-meter imagery with stratified soil sampling (0–120 cm depth) across 79 gullies with comparable slopes gradient and catchment areas on a farm (570 km<sup>2</sup>) in the black soil region of northeast China to quantify how erosion-resistant layers control gully sidewall expansion and headcut retreat. Ten soil properties were analyzed to construct a PCA-based comprehensive soil erosion resistance score (CRS), revealing a decline in CRS with profile depth and a hierarchy of soil resistance: Black soil > Black soil-Loess transition layer > Loess > Loess-Sand transition layer > Fluvial sandy. The first two layers were identified as erosion-resistant layers. Through threshold effect analysis, a threshold erosion-resistant layer thickness of 53.88 cm was identified (<em>p</em> < 0.01) for sidewall expansion, revealing a 1.36 cm/yr acceleration in gully sidewall expansion per 1 cm thinning within the threshold thickness. Gullies with erosion-resistant layers below the sensitivity thickness experienced 2.03 times higher expansion rate. Gullies newly formed since 2010 exhibited a lower threshold (34.90 cm) than the pre-existing gullies. Gully headcut retreat rate was 43 % higher if the resistant layer was thinner than 54.28 cm, despite no significant detectable threshold. The threshold erosion-resistant layer thickness is potentially modulated by the depth of soil cracks and needs further investigation. This study highlights the importance of soil-profile features, not just surface properties, in gully erosion research. Integration of this threshold into gully erosion models could revolutionize gully prediction and precision conservation strategies.</div></div>","PeriodicalId":49503,"journal":{"name":"Soil & Tillage Research","volume":"259 ","pages":"Article 107059"},"PeriodicalIF":6.8,"publicationDate":"2026-01-09","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145941286","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":1,"RegionCategory":"农林科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2026-01-09DOI: 10.1016/j.still.2026.107066
Marcelo Camponez do Brasil Cardinali , Jarbas Honorio Miranda , Quirijn de Jong Van Lier , Tiago Bueno Moraes
Multimodal soil pore structures introduce substantial challenges for deriving hydraulic properties, including the estimation of hydraulic conductivity from water retention data. Conventional models often have difficulty representing the complexity of multimodal pore systems, motivating the development of more flexible approaches. In a recent paper, we demonstrated that a new model based on the Inverse Laplace Transform (ILT) can be used to estimate the pore size distribution (PSD) from soil water retention curves (SWRC), providing a flexible alternative to traditional parametric models. The present study extends the ILT methodology to determine soil hydraulic conductivity in unsaturated soils. We derive a closed-form equation for the hydraulic conductivity function within the ILT–Gauss method and validate it using a dataset from the UNSODA database that includes paired soil water retention and hydraulic conductivity measurements. The results demonstrate that hydraulic conductivity was accurately predicted, yielding statistical performance comparable to conventional unimodal and multimodal van Genuchten models. The main advantage of the new method is its ability to implicitly capture multimodal pore systems when evaluating unsaturated hydraulic conductivity and, consequently, soil water dynamics in such soils.
{"title":"Estimating soil hydraulic conductivity by Inverse Laplace Transform","authors":"Marcelo Camponez do Brasil Cardinali , Jarbas Honorio Miranda , Quirijn de Jong Van Lier , Tiago Bueno Moraes","doi":"10.1016/j.still.2026.107066","DOIUrl":"10.1016/j.still.2026.107066","url":null,"abstract":"<div><div>Multimodal soil pore structures introduce substantial challenges for deriving hydraulic properties, including the estimation of hydraulic conductivity from water retention data. Conventional models often have difficulty representing the complexity of multimodal pore systems, motivating the development of more flexible approaches. In a recent paper, we demonstrated that a new model based on the Inverse Laplace Transform (ILT) can be used to estimate the pore size distribution (PSD) from soil water retention curves (SWRC), providing a flexible alternative to traditional parametric models. The present study extends the ILT methodology to determine soil hydraulic conductivity in unsaturated soils. We derive a closed-form equation for the hydraulic conductivity function within the ILT–Gauss method and validate it using a dataset from the UNSODA database that includes paired soil water retention and hydraulic conductivity measurements. The results demonstrate that hydraulic conductivity was accurately predicted, yielding statistical performance comparable to conventional unimodal and multimodal van Genuchten models. The main advantage of the new method is its ability to implicitly capture multimodal pore systems when evaluating unsaturated hydraulic conductivity and, consequently, soil water dynamics in such soils.</div></div>","PeriodicalId":49503,"journal":{"name":"Soil & Tillage Research","volume":"259 ","pages":"Article 107066"},"PeriodicalIF":6.8,"publicationDate":"2026-01-09","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145915149","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":1,"RegionCategory":"农林科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2026-01-09DOI: 10.1016/j.still.2025.107054
Qinglong Zhang , Ce Wang , Meixiang Xie , Wei Qi , Genxiang Feng , Zhanyu Zhang , Yuanjie Li
Desiccation cracks in clayey soils are prone to alternate appearance, propagation, self-healing, and recurrence in the same vicinity when subjected to wet-dry cycles. Cracks alter the energy-driven mechanism from capillary potential dominance to viscous or gravitational dominance, thus inducing preferential flow of water, fertilizers, pesticides and microplastics, etc. However, the mechanisms by which healed, residual or recurring cracks further trigger preferential flow remain to be elucidated. This study investigated crack healing, recurrence, and their prolonged influence on preferential flow during four wet-dry cycles using deep-learning-based crack image analysis and bromide breakthrough curve monitoring. Results showed a decline in crack intensity with increasing cycles but persistent spatial recurrence, with over 65 % similarity between drying stages. The crack recurring similarity between adjacent dry cycles was greater than that between more distant cycles, indicating incomplete healing of crack-induced structural damages. Across wet-dry cycles, breakthrough curves exhibited progressive left-skewing with earlier peak arrivals (45.4 % earlier than that in the first cycle) and heightened peak concentrations, confirming intensified preferential flow despite diminished surface cracking. The Mobile-Immobile model effectively described the breakthrough curve from a physical point of view of two domains (R² > 0.9) and also corroborated gradual left-skewing migration of the preferential breakthrough curve across wet-dry cycles. Pearson correlation analysis revealed that despite a visible decline in surface cracking, internal residual cracks and evolving pore connectivity may sustain or even enhance preferential flow. This study revealed the recurrence mechanism of desiccation cracks under multi-stage wet-dry cycles and their potential temporal stability as preferential pathways. This study provides a theoretical basis for the inhibition and restoration of desiccation cracks, as well as for the prevention of deep percolation of water and leaching of nutrients in farmland soils.
{"title":"Soil crack healing, recurrence and the temporal persistence of preferential flow under wet-dry cycles revealed by deep-learning image analysis and breakthrough curves","authors":"Qinglong Zhang , Ce Wang , Meixiang Xie , Wei Qi , Genxiang Feng , Zhanyu Zhang , Yuanjie Li","doi":"10.1016/j.still.2025.107054","DOIUrl":"10.1016/j.still.2025.107054","url":null,"abstract":"<div><div>Desiccation cracks in clayey soils are prone to alternate appearance, propagation, self-healing, and recurrence in the same vicinity when subjected to wet-dry cycles. Cracks alter the energy-driven mechanism from capillary potential dominance to viscous or gravitational dominance, thus inducing preferential flow of water, fertilizers, pesticides and microplastics, etc. However, the mechanisms by which healed, residual or recurring cracks further trigger preferential flow remain to be elucidated. This study investigated crack healing, recurrence, and their prolonged influence on preferential flow during four wet-dry cycles using deep-learning-based crack image analysis and bromide breakthrough curve monitoring. Results showed a decline in crack intensity with increasing cycles but persistent spatial recurrence, with over 65 % similarity between drying stages. The crack recurring similarity between adjacent dry cycles was greater than that between more distant cycles, indicating incomplete healing of crack-induced structural damages. Across wet-dry cycles, breakthrough curves exhibited progressive left-skewing with earlier peak arrivals (45.4 % earlier than that in the first cycle) and heightened peak concentrations, confirming intensified preferential flow despite diminished surface cracking. The Mobile-Immobile model effectively described the breakthrough curve from a physical point of view of two domains (R² > 0.9) and also corroborated gradual left-skewing migration of the preferential breakthrough curve across wet-dry cycles. Pearson correlation analysis revealed that despite a visible decline in surface cracking, internal residual cracks and evolving pore connectivity may sustain or even enhance preferential flow. This study revealed the recurrence mechanism of desiccation cracks under multi-stage wet-dry cycles and their potential temporal stability as preferential pathways. This study provides a theoretical basis for the inhibition and restoration of desiccation cracks, as well as for the prevention of deep percolation of water and leaching of nutrients in farmland soils.</div></div>","PeriodicalId":49503,"journal":{"name":"Soil & Tillage Research","volume":"259 ","pages":"Article 107054"},"PeriodicalIF":6.8,"publicationDate":"2026-01-09","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145941285","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":1,"RegionCategory":"农林科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
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