Diagnosing and Restoring Degraded Croplands: Nutrient Constraints, Abiotic Stress, Greenhouse Gas Mitigation, and Restoration Pathways

Cropland degradation severely impairs soil fertility, nutrient cycling, crop productivity, and food security, especially in regions characterized by acidic soils, organic matter depletion, nutrient imbalance, soil erosion, and intensive agricultural management. In addition, climate-driven abiotic stressors such as drought, extreme rainfall, heatwaves, and soil salinization are increasingly recognized as critical co-drivers of cropland degradation. Meanwhile, degraded and intensively managed croplands may also contribute to soil carbon loss, nutrient losses, and greenhouse gas emissions, thereby weakening both productivity and climate-regulation functions.Despite growing knowledge of individual degradation mechanisms, practical frameworks for diagnosing the severity of nutrient constraints, identifying critical thresholds at which productivity loss becomes irreversible, and designing spatially targeted restoration interventions remain underdeveloped — particularly for smallholder agricultural landscapes. In degraded agricultural ecosystems, variations in soil organic matter, acidity, nutrient availability, soil structure, water availability, and carbon–nitrogen cycling directly affect root development, nutrient uptake, nutrient use efficiency, vegetation performance, greenhouse gas dynamics, and crop yield formation. Accordingly, integrated understanding of soil degradation mechanisms and their impacts on plant nutrition, abiotic stress responses, carbon sequestration, and greenhouse gas mitigation is essential for developing targeted restoration interventions.This Research Topic aims to bring together studies that investigate the monitoring, diagnosis, mechanisms, critical thresholds, and restoration pathways of degraded croplands from the perspective of plant nutrition, abiotic stress, and climate-smart soil management. Attention will be given to how soil degradation processes, such as soil acidification, organic matter loss, nutrient depletion, erosion, drought, salinization, and greenhouse gas emissions, influence plant nutrient acquisition, plant growth, nutrient cycling, productivity restoration, and sustainable crop production. We also welcome studies that integrate field experiments, long-term monitoring, soil and plant analysis, remote sensing, machine learning, threshold identification, and decision-support tools to reveal degradation mechanisms and develop practical strategies for improving soil fertility, nutrient use efficiency, carbon sequestration, and crop productivity.Potential contributions may address, but are not limited to:1. Monitoring and assessment of cropland degradation, soil fertility decline, nutrient limitation, abiotic stress constraints, productivity constraints, and greenhouse gas emissions based on field observations, remote sensing, machine learning, or multi-source data fusion;2. Impacts of soil acidification, organic matter dynamics, nutrient imbalance, soil erosion, drought, salinization, and greenhouse gas emissions on plant growth, nutrient uptake, nutrient use efficiency, and crop productivity;3. Plant–soil interactions, root–soil processes, and vegetation responses in degraded and abandoned croplands, with emphasis on nutrient cycling impairment, carbon–nitrogen interactions, and productivity constraints rather than species-level physiological tolerance or microbiome dynamics;4. Critical thresholds of soil degradation, nutrient limitation, soil acidity, organic matter loss, water or salt stress, erosion, and carbon loss in regulating plant growth, yield formation, greenhouse gas emissions, and productivity restoration;5. Nutrient management, fertilization optimization, acid soil amelioration, organic matter improvement, salinization mitigation, water management, green manure incorporation, and conservation practices for soil fertility restoration and greenhouse gas mitigation in degraded croplands;6. Empirical evidence and modelling frameworks for identifying critical degradation thresholds, such as soil acidity levels, organic matter minima, erosion rates, nutrient loss intensity, and greenhouse gas emission risks, below which standard nutrient management fails and more intensive restoration intervention is required;7. Landscape-scale diagnosis and regional restoration prioritization for improving soil fertility, reducing nutrient and water losses, enhancing soil carbon sequestration, and promoting productivity recovery under changing climate conditions;8. Climate-driven abiotic stress in croplands, including drought, extreme rainfall, heatwaves, and salinization, and their impacts on plant–soil relations, soil water dynamics, greenhouse gas emissions, and crop productivity, as well as approaches for their monitoring and management;9. Decision-support systems and regional targeted restoration frameworks for improving soil fertility, nutrient use efficiency, water use efficiency, carbon sequestration, greenhouse gas mitigation, and sustainable crop production.By integrating cropland degradation monitoring with plant nutrition mechanisms, threshold identification, carbon–nitrogen cycling, greenhouse gas mitigation, and restoration management, this Research Topic seeks to advance our understanding of how degraded agricultural soils can be restored to support efficient nutrient use, stable crop production, sustainable land management, climate-smart agriculture, and long-term food security. Topic editors: Yingcong Ye, Eugenio Straffelini, Guopeng Zhou, Yefeng Jiang Source: https://www.frontiersin.org/research-topics/83730/diagnosing-and-restoring-degraded-croplands-nutrient-constraints-abiotic-stress-greenhouse-gas-mitigation-and-restoration-pathways