Modeling soil organic carbon loss in arid agroecosystems: A mixed-effects approach to abandoned wheat fields

Abstract

The management of abandoned lands is critical for carbon sequestration in arid ecosystems, where soil organic carbon (SOC) dynamics play a key role in mitigating land degradation. In abandoned croplands, SOC dynamics are especially important, as they influence carbon storage in regions vulnerable to climate change and unsustainable practices. This study assesses how short-term wheat field abandonment (STWFA) interacts with soil properties and environmental factors to drive SOC depletion in Iran's Zayandeh-Rood River Basin, a region emblematic of water-stressed agroecosystems. By integrating Sentinel-2-derived crop rotation maps, Landsat-8 thermal data for land surface temperature, and field-measured soil parameters (clay content, bulk density, salinity), we applied a linear mixed-effects model to unravel the time-dependent effects of abandonment on SOC over a five-year period (2020–2024). Results revealed a significant decline in SOC with prolonged abandonment (β = −0.413 per year, p < 0.001), exacerbated by elevated LST (β = −0.014, p = 0.006) and reduced the stabilization of soil organic carbon through clay content (STWFA × clay: β = −0.010, p = 0.029). The model explained 75–80 % of SOC variability, with abandonment duration, LST, and clay content being the primary contributors to this variance. Regional differences accounted for 24 % of the variance, highlighting the spatial heterogeneity of SOC dynamics. These findings underscore that arid abandoned wheat fields face compounding SOC losses driven by climatic stress and soil texture dynamics, highlighting the need for actionable strategies such as intermittent revegetation to mitigate carbon loss and enhance soil resilience in water-scarce regions.