Effects of cultivation and agricultural abandonment on soil carbon, nitrogen and phosphorus in a meadow steppe in eastern Inner Mongolia

•Cultivation significantly decreased soil OC and TN but increased soil TP.•Cultivation significantly reduced soil C:N, C:P and N:P ratios.•The present abandonment significantly elevated soil OC and TN compared with cropland.•The cultivation-compaction effect caused an 8.7–17.8 % underestimate of the nutrient stock change ratio.