Potentially toxic trace element pollution in long-term fertilized agricultural soils in China: A meta-analysis

Fertilization results in potentially toxic trace element (PTTE) pollution agricultural soils. However, it is unclear which factors determine the effect sizes of fertilization on PTTEs at multiple spatial-temporal scale. This work synthesized 379 observations 78 field sites (3–35 years) across China's main grain producing areas, and showed that long-term organic significantly enhanced total Cu, Zn Cd by 25.7%, 18.9% 66.6%, soil available 60.5%, 155.3% 83.6%, respectively; whereas inorganic increased only an average 6.3%. Organic fertilizer (OF) type application rate dominated variation PTTE concentrations, where approximately one-half (42.6% 47% Cd) was observed. Furthermore, OFs containing less than 1 mg kg?1 were recommended to be safely applied Soil factor under determining variation, resulted higher risk some soils such as Alfisols Semi-hydromorphic soils, we suggested use lower amounts P fertilizers or ones having small PTTEs. In short, caused serious especially Chinese croplands, strategies with a focus towards reducing must developed, e.g., promoting straw return, forbidding addition feeds feed additives, improving carbon sequestration efficiency (CSE) thus matter (SOM).