Magnesium (Mg) is an essential element for plant growth and human health. Its availability and spatial distribution in soils depends on a wide variety of intrinsic and extrinsic factors. Understanding how Mg availability changes in space and time is crucial for preventing potential deficiencies. In 1987, a soil-monitoring network (FRIBO) was launched in the canton of Fribourg, Switzerland. It was based on 250 sites distributed evenly throughout the canton so as to include a large variety of soil types (Cambisols, Gleysols, Rendzinas, Regosols, Lithosols, Luvisols and Fluvisols) under three different land use types (croplands, permanent grasslands and mountain pastures). The aim of this research was to characterize the spatial and temporal variation of total and available forms of Mg in the agricultural soils of the canton of Fribourg and to discuss potential implications for Mg fertilization management. Total Mg concentration (Mg_T) averaged 5.5 g kg⁻¹, with small differences between land use types. Spatial distribution of Mg_T showed higher values on the southern part of the study area, mostly on Rendzinas and Cambisols. Average concentrations of available Mg forms were significantly different according to extraction methods, with water extraction (Mg_H2O) having the lowest value (14.2 mg kg⁻¹) followed by calcium extraction (Mg_CaCl2, 109.4 mg kg⁻¹) and ammonium acetate + EDTA extraction (Mg_AAE, 148.7 mg kg⁻¹). On average, permanent grasslands had significantly higher values for all Mg forms compared to croplands and mountain pastures, a result further corroborated by the analysis of spatial distribution. Intrinsic factors, such as soil type and terrain attributes, appeared to have a major influence on total Mg content, whereas available Mg forms depended mostly on extrinsic factors, such as land use type. Temporal analysis of soil available Mg forms revealed an overall increase between 1987 and 2016, especially after a land use change from croplands to permanent grasslands. In the light of the essential role of Mg for plant growth and development, as well as its critical role in animal health, the status of Mg should continue to be monitored in the FRIBO network and plant analysis should be implemented.

镁（Mg）是植物生长和人类健康的重要元素。其在土壤中的可用性和空间分布取决于各种各样的内在和外在因素。了解镁的时空分布如何变化对于防止潜在的缺陷至关重要。1987年，瑞士弗里堡州启动了土壤监测网络（FRIBO）。它基于在整个州平均分布的250个地点，从而包括三种不同土地利用类型（农田，永久性草地和高山牧场）下的多种土壤类型（坎比索尔，格列索尔，Rendzinas，雷哥索尔，石蜡土，卢维索尔和氟维索尔）。 ）。这项研究的目的是表征弗里堡州农业土壤中镁的总量和可用形态的时空变化，并讨论其对镁施肥管理的潜在影响。总镁浓度（Mg_T）平均为5.5 g kg ^-1，土地使用类型之间的差异很小。在研究区域的南部，主要在Rendzinas和Cambisols上，Mg _T的空间分布显示出较高的值。可用的镁形式的平均含量分别显著不同根据提取方法，用水萃取（MG _H2O）具有最低值（14.2毫克千克^-1随后钙提取）（MG_{的CaCl 2}，109.4毫克千克^-1）和乙酸铵+ EDTA萃取（Mg _AAE， 148.7 mg kg ^-1）。平均而言，与耕地和高山牧场相比，永久性草地的所有Mg形式的价值都高得多，通过空间分布分析进一步证实了这一结果。内在因素（例如土壤类型和地形属性）似乎对总镁含量具有主要影响，而可用的镁形态则主要取决于外在因素（例如土地利用类型）。对土壤中有效镁形态的时间分析显示，1987年至2016年间总体增加，特别是在土地使用方式从耕地变为永久草地之后。鉴于镁对植物生长和发育的重要作用及其在动物健康中的关键作用，应继续在FRIBO网络中监测镁的状况，并应进行植物分析。