赤泥和有机肥对镉、铅在水稻中吸收分布的影响

通过大田正交试验，研究添加赤泥和有机肥对Cd、Pb在土壤-水稻系统中分布规律的影响。结果表明，添加赤泥或有机肥后，水稻根际土壤pH值升高0.36～1.90个单位，根际土壤中Cd、Pb含量分别降低2.73%～26.25%和7.15%～34.26%，糙米中Cd和Pb含量分别降低23.24%～55.90%和11.76%～29.41%，其中单施赤泥效果最好，其次是配施，单施有机肥最差。添加赤泥和有机肥后，水稻各器官中Cd和Pb含量显著降低，不同生育期Cd和Pb的贡献率明显改变，且添加量及施肥方式（单施、配施）也有显著影响。与CK相比，降Cd效果最好的是单施赤泥4 000 kg·hm^-2，降幅为55.90%；降Pb效果最好的是赤泥（4 000 kg·hm^-2）与有机肥（1 000 kg·hm^-2）配施，降幅为29.41%。由于土壤中Cd（超标65倍）、Pb（超标7倍）污染程度较高，糙米中Cd、Pb含量仍超过食品污染物限量（GB 2762-2012）。因此，在重金属污染程度较高的稻田，仅通过添加土壤调理剂不能达到安全生产的目的。

Effects of Red-mud and Organic Fertilizer on Cadmium and Lead Absorption and Distribution in Rice

Effects of red mud and organic fertilizer on distribution of cadmium(Cd) and lead (Pb) in soil-rice system were studied in field by orthogonal test. Results showed that after red mud and organic fertilizer added including single and combined, the soil pH value increased 0.36~1.90 units, contents of Cd and Pb in rice rhizosphere soil decreased 2.73%~26.25% and 7.15%~34.26% respectively and contents of Cd and Pb in brown rice decreased 23.24%~55.90% and 11.76%~29.41% respectively. In all treatments, single red mud was best, followed by red mud and organic fertilizer combined, single organic fertilizer was worst. The content of Cd and Pb in different rice organs with addition of red mud and organic fertilizer decreased significantly, the contribution rate of Cd and Pb at different stages changed obviously, and influences of adding quantity and fertilizing method were also significant. Different treatments had different effects on contents of Cd and Pb in brown rice. Compared with CK, red mud (4 000 kg·hm^-2) was the best for Cd, combination of red mud (4 000 kg·hm^-2) and organic fertilizer (1 000 kg·hm^-2)was the best for Pb, the contents of which were 55.90% and 29.41% less than the control respectively. Although contents of Cd and Pb in brown rice decreased significantly after red mud and organic fertilizer added, contents of Cd and Pb in brown rice were still higher than national food safety standards (GB 2762-2012) because of high polluted degree of Cd (65 times than standard) and Pb(7 times than standard) in soil. All results showed it was ineffective to control heavy metal pollution in brown rice only by red mud and organic fertilizer addition in high polluted degree soils.