P Fertilizer Led To The Accumulation Of Heavy Metals In The Soil - Rice System

In this article rice were treated by different doses of phosphate, several heavy metal elements, such as Cd, Pb, As and Hg in soil and various organs of rice were analyzed by dynamic measurement. In order to study the rules of distribution and accumulation, dynamic change and the rules of enrichment of the four heavy metal elements in soil and various organs of rice, and hope to give theoretical basis for production non-pollution rice and green rice. The results showed:1 The distribution of Cd. Pb. As and Hg in soil-rice system under different level of phosphate.In mature stage, the content of Cd, Pb, As and Hg in soil and various organs of rice in CK were lower than other treatments. With the increasing amount of application of phosphate fertilizer, the content of Cd, Pb, As and Hg in soil and various organs of rice were significantly different, although the differences between every treatment were not very significant, but it showed that the content of Cd, Pb, As and Hg in soil and plants related to phosphate, and mostly exist a clear dose-response. The mass fraction of the distribution of descending order of heavy metals Cd, Pb, As and Hg in soil and rice plants in different organs were as follows:root>ear>leave>stem;root>soil>leave>ear>stem;root>soil>leave> stem>ear; soil>root>stem>leave>ear.2. Dynamic changes of heavy metals Cd, Pb, As and Hg in soil and various organs of rice plant under different phosphate levelsFrom early July to early October, the general trend of Cd content in soil was increased after decreased. The dynamic changes of Cd in roots and leaves were same, reduced after the first rise. Cd content in stems was decreased after increased. The overall trend in levels was increased. From early July to early October, the overall trend of Pb content in soil was rise rapidly, and then decreased slowly. The Pb content in roots was increased first, and decreased secondly, and then increased. The trend of Pb content in leaf was increase after a decline. The overall trend content of Pb in stem was first increased and then decreased. The overall trend of Pb in ear was slowly increased. From early July to early October, the general trend of As content in soil was increased after decreased. The As content in roots was increased first, and decreased secondly, and then increased. The overall trend in levels was increased in stems was decreased, in ears was increased. Cd content in soil was decreased after increased. The trend of Hg content in root was smooth in addition to a few high-value occurred in early October. The overall trend in leave was decrease after increased. The trend of Hg content in stem was declined, in ear was first increased and then decreased.3. Correlation of Cumulative between heavy meals and soil and rice organs under different levels of phosphateThe accumulated contention of Cd, Pb, As and Hg in soil and various organs of rice had reached a very significant correlation with phosphate fertilization, in addition in roots.4. The enrichment rule of heavy metal in soil-rice system under different levels of phosphate.The enrichment Coefficient of Cd, Pb, As and Hg was highest in root. Different heavy metals in stems, leaves and ears were different, Cd: ear>leave>stem;Pb:leave>ear>stem;As:leave>stem>ear;Hg:stem>leave>ear. 5. Heavy metals content in soil and rice compared with the national limit standardCd in soil was beyond the limits. Pb, As and Hg in soil were in the limits.As and Hg in grains were within limits, while Cd and Pb in grain were beyond the limits. The yield of T3 was highest, reached 9130kg/hm2 Under phosphate levels (26kg/hm2), the yield and quality of T3 had reached the best value.