Real‐Time Measurement of Soil Organic Carbon and Related Properties Across Agricultural Land Types Using Mobile Near‐Infrared Spectroscopy

New mobile near‐infrared spectroscopy (NIRS) technology allows more frequent nutrient analysis of soil and plant properties among farms and agricultural land uses in real‐time. The aim of this study was to determine key soil organic carbon (SOC) and plant properties using real‐time mobile NIRS technique, and to assess metrics for SOC and its association with plant properties across agricultural land types. A total of 101 fields of either arable, temporary ley or permanent grassland were studied across five farms in spring 2023 and 2024 in the UK. The study collected 505 soil and 505 plant samples from the same location, with nutrients analysed using NIRS. A linear mixed model was used to assess differences among land types. The main SOC associated and plant properties assessed were soil depth, SOC (g/kg, tonnes/ha, ratios with nitrogen and clay), plant height, biomass cover and common plant nutrients. Among the land types studied, the majority of soil samples from permanent grassland had a very good SOC/clay ratio (72%), whereas arable and temporary ley samples were predominantly of good (41% and 46%, respectively) or moderate (22% and 28%, respectively) levels. Regional differences were found in soil depth (ranging from 18.3 to 30 cm), SOC stock (ranging from 46.2 to 65.3 t/ha) and SOC/clay ratio (ranging from 0.12 to 0.16). The mobile NIRS analysis can aid large scale monitoring of both soil and plant nutrients, with more frequent measurements helping landowners manage organic carbon stocks.