Evaluating the Trade-Offs between Nutrient and Cadmium Levels in Soils in Northeastern China: Accounting for Variations in Soil Factors

Abstract

Agricultural soils have relied on the application of fertilizers to enhance soil fertility and yields in response to increasing food demands. However, the potentially hazardous trace elements that accumulate in soils have been largely overlooked. In this study, we set out to determine the soil factors in croplands using Exploratory Factor Analysis to illuminate the trade-off between soil surplus nutrients and cadmium (Cd) accumulation as a result of fertilizer application. Our research in northeastern China highlights the fact that studies tend to ignore the accumulation and distribution of hazardous heavy metals in production fields in favor of an over-emphasis on soil fertility indicators, which is unsustainable. Our model showed that soil nutrient could be identified based on three soil factors: soil organic matter, soil available nutrients, and soil nutrient buffer structures. Fertilization enhances the available nutrients (especially available P) and plays a significant role in soil nutrient cycling. However, the long-term application of P leads to a P-surplus and leaves soils more susceptible to Cd accumulation. The 90th percentile estimate of soil Cd concentration was 1.4 times higher than the P-optimal level. Scenario analyses of long-term fertilizer management indicated that, over a 50-year simulation period, the impact of Cd accumulation in soils in traditional agriculture was insignificant. However, prolonged application of excess phosphorus fertilizer would lead to a continuous increase in the concentration of accumulated Cd from 0.17 mg kg−1 to 0.40 mg kg−1.

Keywords: Exploratory Factor Analysis, Soil nutrient, Cadmium accumulation, Trade-off