This Special Issue presents a collection of papers commissioned to celebrate the UK Centre for Doctoral Training (CDT) in soil science known as ‘STARS’ (Soils Training And Research Studentships). The collection was written by emerging scientists and their collaborating supervisory teams. The call for papers was principally aimed at STARS students, but submissions were also encouraged from students in the wider UK soils community, who are also represented.

The STARS CDT was originally commissioned in 2015 as part of a funding collaboration between the UK Natural Environment Research Council and the UK Biotechnology and Biological Science Research Council (BBSRC). The paper by Haygarth et al. (2021) provides a reflection on the STARS CDT experience, exploring what can be learnt from the new pedagogic approach. It describes how a discipline-focussed doctoral centre is a novel and unique way of teaching and learning soil science, proposing that this might be a model for future post graduate soil science teachers to learn from, in order to continually improve and innovate in the way we train our PhD students.

In total, the Special Issue contains 17 papers, of which 15 appear in hard copy (incidentally, the last hard copy issue of the European Journal of Soil Science before conversion to solely on-line publication). All but one of the papers (Haygarth et al., 2021) are student-led, with three by non-STARS students (Jonah Prout, Yan Ma and Melanie Armbruster). The papers loosely fall into three categories: (1) Those involving local-scale controlled experiments and method development (seven papers), (2) those focussed on empirical analyses of large-scale datasets (six papers) and (3) those that involve a meta-analyses of previously published literature (three papers).

In the first category, Chris McCloskey contributes two papers as lead author. In the first paper (McCloskey et al., 2020), a field system is presented for measuring plant and soil carbon fluxes using stable isotope methods, with sufficient precision to resolve diurnal and seasonal patterns. In the companion paper, the field system is used to demonstrate the importance of allowing for transient variation in plant and soil δ¹³C end members in partitioning fluxes from net ecosystem respiration (McCloskey et al., 2021). Ma et al. (2021) assessed the relative efficacy of nitrification inhibitors in a highly nitrifying soil and, like McCloskey, used carbon-labelling techniques to help achieve this. Dan Evans takes us to the core of soil formation, using a new technique of cosmogenic radionuclide analysis (Evans et al., 2021) with a conclusion that questions the accuracy of our existing soil formation knowledge, arguing that we must consider the bulk density profile of the overlying soil. At a slightly larger scale, ‘Bee’ Burak et al. (2020) uses an inductive mesocosm-based assessment to study how root hairs affect soil erosion by simulated rainfall. In similar controlled conditions, Corina Lees et al. (2020) used a growth room to control her climate change study in selecting plant traits for soil erosion control in grassed waterways. Marta Cattin et al. (2021) also uses controlled conditions with a 21-day laboratory microcosm incubation in order to assess the fate of soil carbon following the application of anaerobic digestate.

In the second category, Fiona Seaton et al. (2020) uses an empirical data-driven analysis based on national (Welsh) monitoring of soil indicators to reflect on soil health, using large-scale data analyses (over 1350 topsoils) to understand the state and change of soils at a national scale. Her work shows the importance of land-use management in determining the soil health and functional capacity of soils. In an empirical approach not dissimilar, Armbruster et al. (2020) has a focus on bacterial and archaeal taxa as potential indicators of soil restoration across grasslands. The work highlights that microbial taxon are among the most sensitive indicators of soil restoration. Paul George et al. (2020) studied anaerobes and sulphate-reducing bacteria in relation to pH across varied land uses, using a nationwide ‘metabarcoding’ dataset from 436 sites belonging to seven contrasting temperate land uses. Andrew Tweedie et al. (2021) tested the hypothesis that phosphorus forms and functions in agricultural soils have changed over a period of 50–70 years, using topsoils from 35 agricultural sites in Northeast Scotland, compared at ‘original’ and ‘resampled’ timepoints. The paper by Hannah Cooper (2021) uses a broadly similar ‘long-term’ sampling approach and considers how long-term zero-tillage enhances the protection of soil carbon in tropical agriculture, studying soil samples collected from experimental fields in Botucatu, Brazil, which had been under zero-tillage for 2, 15 and 31 years. The paper by Prout et al. (2020) focusses on soil organic matter and proposes an index approach based on organic carbon-to-clay ratio. Again, like the above papers this work was empirically based, using 3809 sites from the National Soil Inventory of England and Wales.

In the third category, Harry Barrat studied the impact of drought and rewetting on nitrous oxide emissions from soil in temperate and Mediterranean climates (Barrat et al., 2020). The method used the first meta-analysis and synthesis of the literature. Anchen Kehler et al. (2021) also applied a literature-based approach to her work, trying to predict how soil phosphorus will react to climate change. Finally in a wonderful collaborative article between the STARS students, Mihai Cimpoiasu et al. (2021) was first author on a reflective consideration of future priorities for soil science: ‘Comparing perspectives from scientists and stakeholders’.

Soil science has never seemed so topical, providing services underpinning our existence (Haygarth & Ritz, 2009) while addressing sustainable development and global grand challenges (Lal et al., 2021). It is thus timely to see this collection led by early career scientists on Innovations in Soil Science to Address Global Grand Challenges. Moreover, it is encouraging, not only because of the diversity of research findings themselves, but because of the promise it shows for our future capacity to deliver the discipline.

本特刊提供了一系列论文，旨在庆祝英国土壤科学博士培训中心 (CDT)，即“STARS”（土壤培训和研究奖学金）。该合集由新兴科学家及其合作监督团队撰写。论文征集主要针对 STARS 学生，但也鼓励来自更广泛的英国土壤社区的学生提交论文，他们也有代表。

STARS CDT 最初于 2015 年作为英国自然环境研究委员会与英国生物技术和生物科学研究委员会 (BBSRC) 之间资助合作的一部分而委托。Haygarth 等人的论文。( 2021 ) 反映了 STARS CDT 的经验，探索可以从新的教学方法中学到什么。它描述了以学科为中心的博士生中心如何成为一种新颖独特的土壤科学教学和学习方式，并提出这可能成为未来研究生土壤科学教师学习的典范，以不断改进和创新我们培训我们的博士生。

特刊总共包含 17 篇论文，其中 15 篇以硬拷贝形式出现（顺便说一下，这是《欧洲土壤科学杂志》在转换为纯在线出版物之前的最后一期硬拷贝）。除了其中一篇论文（Haygarth 等人，2021 年）之外，所有论文 都是由学生主导的，其中三篇是由非 STARS 学生（Jonah Prout、Yan Ma 和 Melanie Armbruster）撰写的。这些论文大致分为三类：（1）涉及局部规模控制实验和方法开发的论文（七篇论文），（2）专注于大规模数据集实证分析的论文（六篇论文）和（3）涉及对先前发表的文献（三篇论文）的元分析。

在第一类中，Chris McCloskey 作为主要作者贡献了两篇论文。在第一篇论文 (McCloskey et al.,  2020 ) 中，提出了一种使用稳定同位素方法测量植物和土壤碳通量的现场系统，具有足够的精度来解决昼夜和季节模式。在配套论文中，田间系统用于证明允许植物和土壤 δ ¹³ C 末端成员瞬时变化在分配来自净生态系统呼吸的通量方面的重要性（McCloskey 等人，  2021 年）。马等人。( 2021) 评估了硝化抑制剂在高度硝化土壤中的相对功效，并且像麦克洛斯基一样，使用碳标记技术来帮助实现这一目标。丹·埃文斯 (Dan Evans) 使用宇宙放射性核素分析新技术（Evans 等人，2021 年）将我们带到土壤形成的核心， 其结论质疑我们现有土壤形成知识的准确性，认为我们必须考虑容重剖面上覆土壤。在更大的范围内，“蜜蜂”布拉克等人。( 2020 ) 使用基于中观的归纳评估来研究根毛如何通过模拟降雨影响土壤侵蚀。在类似的受控条件下，Corina Lees 等人。( 2020) 使用生长室来控制她的气候变化研究，以选择植物性状以控制草地水道中的土壤侵蚀。玛塔·卡特汀等。( 2021 ) 还使用受控条件和 21 天的实验室微观孵化来评估应用厌氧消化物后土壤碳的归宿。

在第二类中，Fiona Seaton 等人。( 2020 ) 使用基于国家（威尔士）土壤指标监测的经验数据驱动分析来反映土壤健康状况，使用大规模数据分析（超过 1350 表土）来了解全国范围内土壤的状态和变化。她的工作表明了土地利用管理在确定土壤健康和土壤功能能力方面的重要性。在一种相似的经验方法中，Armbruster 等人。( 2020 ) 重点关注细菌和古菌类群，作为草原土壤恢复的潜在指标。这项工作强调微生物分类群是土壤恢复最敏感的指标之一。保罗乔治等人。( 2020) 研究了厌氧菌和硫酸盐还原菌与不同土地用途的 pH 值的关系，使用来自全国性的“元条形码”数据集，该数据集来自属于七个对比鲜明的温带土地用途的 436 个地点。安德鲁·特威迪等人。( 2021 ) 使用来自苏格兰东北部 35 个农业地点的表土，在“原始”和“重新采样”时间点进行比较，检验了农业土壤中磷的形式和功能在 50-70 年间发生了变化的假设。Hannah Cooper 的论文（2021 年）) 使用大致相似的“长期”采样方法，并考虑长期零耕如何增强热带农业中土壤碳的保护，研究从巴西博图卡图试验田收集的土壤样本，该试验田一直在零耕下2、15 和 31 年。Prout 等人的论文。( 2020 ) 关注土壤有机质，提出基于有机碳粘土比的指标方法。同样，与上述论文一样，这项工作是基于经验的，使用来自英格兰和威尔士国家土壤清单的 3809 个站点。

在第三类中，Harry Barrat 研究了干旱和再润湿对温带和地中海气候下土壤中一氧化二氮排放的影响（Barrat 等，  2020）。该方法使用了首次荟萃分析和文献综合。Anchen Kehler 等。( 2021 ) 还将基于文献的方法应用于她的工作，试图预测土壤磷对气候变化的反应。最后，在 STARS 学生 Mihai Cimpoiasu 等人之间的精彩合作文章中。( 2021 ) 是第一作者对土壤科学未来优先事项的反思：“比较科学家和利益相关者的观点”。

土壤科学似乎从未如此热门，它为我们的生存提供服务（Haygarth & Ritz，  2009 年），同时应对可持续发展和全球重大挑战（Lal 等人，  2021 年）。因此，现在是时候看到这个由早期职业科学家领导的关于土壤科学创新以应对全球大挑战的系列。此外，它令人鼓舞，不仅因为研究结果本身的多样性，而且因为它对我们未来交付该学科的能力显示出希望。