Crop intensification effects on soil quality and organic carbon stocks: a case study of Haramosh Valley in Central Karakorum, Pakistan

ABSTRACT Agricultural operations such as excessive tillage and intense cropping deplete soil organic carbon (SOC), making sustainable agriculture management critical for reducing greenhouse gas (GHG) emissions. This study evaluates the impact of crop intensification on soil quality and soil organic carbon stocks (SOCS) under double cropping (DC) and single cropping pattern (SC) in upper Haramosh of Gilgit, Pakistan. Soil samples were taken from cropping zones (DC and SC) under three depths (0–20, 20–40, and 40–60 cm). Standard methods were used to analyze selected soil quality parameters and SOC. Statistical analysis using ANOVA showed that soil temperature, moisture, pH, SOC, and SOCS highly significantly differed (p < 0.001) for different cropping patterns (DC and SC), whereas bulk density (BD), electrical conductivity (EC), and clay were not significantly different. The SC retained 4.4% more moisture and had lower BD than the DC, while BD increased with increasing depth. The texture of the soil was sandy loam at both cropping zones. The mean SOC and SOCS of SC were greater (by 12%) than in the DC zone. Pearson correlation showed a significant and positive correlation of SOC stock with SOC, moisture (p < 0.01), and EC (p < 0.05), but had a negative correlation with bulk density, pH (p < 0.01), and sand (p < 0.05). DC apparently degraded soil quality and organic carbon reserves, thus reducing the soil health in mountain agriculture.