Background and aims Soil depth is a critical attribute of any soil, and determines rooting, moisture and nutrient storage, mineral reserve, anchorage, and a range of conditions that affect plant growth. We reviewed papers from four primary soil science journals and extracted how deep the soils were studied in those papers. Methods Soil depth was obtained over a 30-years period (1989–2019) from papers in: European Journal of Soil Science , Geoderma, Plant and Soil , and Soil Biology and Biochemistry . In total, 1146 papers were reviewed, and 37% (420 papers) included information on how deep the soil was studied. Results The number of papers that included soil depth increased from 31% in 1989 to 47% in 2019. The average soil depth studied was 27 cm, but it was 53 cm between 1989 and 1999, and 24 cm between 2004 and 2019. Most of the studies were from Europe, and 41% of the papers contained soil classification. Research that focused on soil mineralogy and technology tended to study soils to a greater depth (average 74 cm), whereas the depth in soil biology research was on average 18 cm. Over 80% of the soils were sampled by fixed depth and not by soil horizon. Conclusions Soil depth is lacking from about half of the papers in these four journals. The depth of the soil studied has halved in the past 30 years. Soil processes, soil properties, and microbial communities are depth-dependent, and for a more complete understanding, soils should be studied to a greater depth.

中文翻译：

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土壤研究的深度——四本土壤科学期刊分析

背景和目标土壤深度是任何土壤的关键属性，它决定着生根、水分和养分储存、矿物储备、锚地以及影响植物生长的一系列条件。我们回顾了四份主要土壤科学期刊的论文，并提取了这些论文中土壤研究的深度。方法 土壤深度是从 30 年（1989-2019 年）的论文中获得的：欧洲土壤科学杂志、地皮、植物和土壤以及土壤生物学和生物化学。总共审查了 1146 篇论文，其中 37%（420 篇论文）包含有关土壤研究深度的信息。结果 包括土壤深度的论文数量从 1989 年的 31% 增加到 2019 年的 47%。研究的平均土壤深度为 27 cm，但 1989 年至 1999 年为 53 cm，2004 年至 2019 年为 24 cm。大多数研究来自欧洲，41% 的论文包含土壤分类。专注于土壤矿物学和技术的研究倾向于研究更深的土壤（平均 74 厘米），而土壤生物学研究的深度平均为 18 厘米。超过 80% 的土壤是按固定深度而不是按土层取样的。结论 这四种期刊中约有一半的论文缺乏土壤深度。在过去的 30 年中，所研究的土壤深度减少了一半。土壤过程、土壤特性和微生物群落都依赖于深度，为了更全面地了解土壤，应更深入地研究土壤。而土壤生物学研究的深度平均为 18 cm。超过 80% 的土壤是按固定深度而不是按土层取样的。结论 这四种期刊中约有一半的论文缺乏土壤深度。在过去的 30 年中，所研究的土壤深度减少了一半。土壤过程、土壤特性和微生物群落都依赖于深度，为了更全面地了解土壤，应更深入地研究土壤。而土壤生物学研究的深度平均为 18 cm。超过 80% 的土壤是按固定深度而不是按土层取样的。结论 这四种期刊中约有一半的论文缺乏土壤深度。在过去的 30 年中，所研究的土壤深度减少了一半。土壤过程、土壤特性和微生物群落都依赖于深度，为了更全面地了解土壤，应更深入地研究土壤。