| As an innovative organic fertilizer, the fungus residue residue can on the one hand solve the non-point source pollution problems of unused fungus residue, and promote the long-term development of circular agriculture on the other hand. In this study, through field test application of fungus residue organic fertilizer for wheat rice rotation cultivation, we investigate the effects of different treatments on heavy metals in soil and crops, and conduct environment risk assessment about heavy metals in farmland soil with the method of potential ecological risk index. A combined method with single factor pollution index and Nemero comprehensive pollution index is applied to accomplish this environment risk assessment. The study aims to secure agricultural production and provide a basis for the promotion of fungus residue. The main conclusions are as follows:(1) In wheat and rice season, four kinds of heavy metals in soil samples were below the class-two limitation of Chinese soil environmental quality standard, which belongs to a safety range without pollution of heavy metals. Among the different treatments soil Cd,Cu and Pb content had no significant difference (p> 0.05) in both season, and soil Cd,Cu, Pb, Zn content under FF1 fungus residue treatment in plow layer was lower than other fertilization treatments.In wheat season, Cd.Cu. Pb. Zn content under FF1 fungus residue treatment of in soil has a decrease of 7.3%,3.9%,1.4% and 0.9% compared with that under CF treatment,and in rice season, Cd,Cu, Pb, Zn content under FF1 fungus residue treatment of in soil has a decrease of 6.8%,4.7%,1.9% and 1.4% compared with that under CF treatment.(2)Among the different treatments, Cu and Zn content in wheat grain reached a significant level (p<0.01). Cd,Cu, Pb,Zn content under for FF1 fungus residue treatment of in wheat grain has a decrease of 14.8%,5%,12.4% and 8.4% compared with that under CF treatment; In wheat shell, among the different treatments Cd,Cu, Pb, Zn content had no significant difference (p>0.05), Cd,Cu, Pb,Zn content under for FF1 fungus residue treatment of in wheat shell has a decrease of 6.5%,3.8%,5.7% and 8.7% compared with that under CF treatment; In the stems and leaves of wheat, no significant difference can be witnessed in Cd,Pb and Zn content (p>0.05), while Cu content reached a significant level (p< 0.01), Cd,Cu, Pb,Zn content under for FF1 fungus residue treatment has a decrease of 2.1%,7.3%,1.1% and 4.8% compared with that under CF treatment.In root of wheat, Cd,Cu, Pb,Zn content under for FF1 fungus residue treatment has a decrease of 6.4%,7.6%,1.4% and 5.1% compared with that under CF treatment.(3) Cd,Cu, Pb,Zn content in rice grains under all treatment had no significant difference (p> 0.05), in which there was 14.3%,13.7%,10.8% and 6.2% decrease of Cd,Cu, Pb,Zn content under FF1 treatment than that under CF treatment; In the rice shell, no significant difference can be witnessed in Cd, Cu and Pb content (p>0.05),whereas Zn reached a significant level (p< 0.01), and the Cd,Cu, Pb,Zn content under FF1 fungus residue treatment had a decrease of 5.6%,5.5%,6% and 7.8% comparing to that under CF treatment; In rice stems and leaves, Zn contents among different treatments reached significant level (p< 0.01), and decreased by 3.3%,3%,3% and 5.4%; In root of rice, no significant difference can be witnessed in Cd and Cu content (p> 0.05), while Pb and Zn content reached a significant level (p< 0.01),Cd,Cu, Pb,Zn content under for FF1 fungus residue treatment has a decrease of 5.7%,8.8%,5.4% and 4.5% compared with that under CF treatment.(4)This study is based on soil element in Dujiangyan. Single factor evaluation showed that, Cu, Pb, Zn in farmland soil provides slight ecological risk, Cd has moderate ecological risk; integrated potential ecological risk index belongs to the range of slight ecological risk; with the two grade national standard of soil environmental quality evaluation, in wheat farmland soil Cd, Cu, Pb, Zn single factor and potential ecological risk index provides the slight ecological risk, integrated potential ecological risk index belongs to the range of slight ecological risk.(5)According to the national food hygiene standard (GB2762-2012), single factor pollution index and Nemero comprehensive pollution index of Cd, Cu, Pb, Zn in wheat has reached a cleanliness level of food safety.(6)Taking ecological environment risks,food safety and economic cost into consideration,confirm the FF1 fungus residue treatment as optimum application amount. |
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