Risk of heavy metal pollution and product quality in tomato-radish-greengrocery cropping system under applications of commercial organic manure and chemical fertilizers

A Field experiment was conducted to assess the impacts of chemical fertilizers and integrated fertilization with commercial organic manure made from feces of domestic animals and chemical fertilizers on the risk of heavy metal pollution in tomato-radish-greens cropping system. The dosages of N, P2O5, and K2O of all treatments were set to equal. The results indicate that the fruit yield of tomato plants as the first season crop was reduced significantly(p0.05) in the treatments applied with lower and medium rates of organic manure and chemical fertilizers, while the yields of radish and greengrocery as the following crops were increased in the treatments applied with organic manure. It was found that the differences of copper, zinc, cadmium and lead concentrations and accumulations in tomato fruit and greengrocery shoot were not significant (p﹥0.05). Lead concentrations in radish flesh root of the treaments with lower and medium rates of organic manure were significantly lower than that with chemical fertilizers, and Lead accumulations in radish flesh root of the treatments with organic manure were significantly lower than that with chemical fertilizers. Cadmium and lead concentrations in edible parts of vegetable crops of all treatments were lower than the limits of these heavy metals in foods (GB18406.12001). Copper was deficit in soil-crops system with chemical fertilizers, and lead accumulations were decreased apparently in the treatments applied with organic manure. These results implied that integrated fertilization could not only remain the balance of zinc and copper as micronutrients, but also minimize the risk of heavy metal pollution in the cropping system.