| This research is aiming to provide reliable theoretical foundation and data support to organic fertilizer rational application during the vegetable cultivation process and prevent soil-vegetable system from organic fertilizer sourced heavy metal pollution, and protecting food safety of agricultural products. On the base of former research, this paper studied the cumulative migration of organic fertilizer sourced heavy metal-element Cu and Zn in the soil-vegetable system, through potted simulation test and long-term field positioning experiment. The result is following:(1) In pot test and field experiment, the total Cu and Zn content has significant positive correlation relationship with organic fertilizer accumulative application. Which means the total Cu and Zn are accumulated constantly following organic fertilizer applying. The exceeding estimate is made through the correlation formulation of total Cu and Zn in soil and organic fertilizer cumulatively application. In the pot test, by using trend line equation when Cu and Zn element cumulative amount reach144kg/ha and96.8kg/ha, the total Cu and Zn content in soil would exceed national secondary standard. In field experiment, through trend line equation when Cu and Zn element cumulative amount reach337kg/ha and636kg/ha, the total Cu and Zn content in soil would exceed national secondary standard.(2) In pot test and field experiment, the effective degrees of Cu and Zn has significant positive correlation relationship with organic fertilizer accumulative application. This show that the effective degrees of Cu and Zn will upgrade with fertilization, it means that continuous fertilization will increase the proportion of available Cu and Zn which is easy to be absorbed.(3) Under OM2and OM3, compare to CK, reducible Cu and Zn, oxidisable Zn significantly enhanced at the same crop in soil. It is said that organic fertilizer can increase acid extracted, reducible Cu and Zn, oxidisable Zn.(4) In comparison with the edible part, Cu and Zn are easier transport from soil to root, It is showing as the amount of Cu and Zn in root is significant higher than that in edible part.The amount of Cu and Zn that transport from soil to edible part will significantly upgrade with fertilization, because the amount of Cu and Zn in edible part under fertilization treatments is higher than CK treatment. And the amount of Zn that transport from soil to edible part is more and more with the continuous fertilization, for the reason that the amount of Zn in edible part of latter crop which fertilization treatments higher than CK treatment is more than before.(5) The transport coefficients of Cu and Zn in same vegetable will significantly upgrade by continuous fertilization, it is showing as the transport coefficients of latter crop under fertilization treatments is higher than before.(6) The transport coefficients of Cu and Zn in celery will significantly upgrade with fertilization in pot test, it is showing as the transport coefficients under fertilization treatments is higher than CK treatment. |
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