田间施用石灰和有机肥对水稻吸收镉的影响

通过大田试验探究不同用量的有机肥与石灰对土壤pH、有机质和Cd有效态含量以及不同生育期水稻各器官中积累Cd的动态变化。结果表明:成熟期水稻各器官Cd含量规律为根>茎>叶片>稻壳>糙米。石灰的施用能显著提高土壤pH,在分蘖期时,低用量石灰与高用量石灰处理下土壤pH分别提高1.35,1.84个单位;有机肥的施用可以增加有机质含量,与对照相比,高用量有机肥处理在分蘖期时有机质含量提高6.60 g/kg,在成熟期提高2.72 g/kg。灌浆期是水稻吸收积累Cd的重要时期,石灰和有机肥的施用均能降低灌浆期土壤中有效态Cd含量,高用量有机肥与高用量石灰处理下土壤有效态Cd含量显著降低,分别降低52.05%和46.87%。有机肥和石灰均能显著降低糙米Cd含量,降Cd效果为高用量有机肥>高用量石灰>低用量有机肥>低用量石灰,高用量有机肥处理的效果最好,糙米Cd含量降低68.20%。

Effects of Applying Lime and Organic Fertilizer on Cadmium Uptake by Rice

Field experiment was conducted to investigate the dynamic changes of soil pH, organic matter and cadmium (Cd) content in soil and Cd accumulation in rice organs at different growth stages under applying different amounts of organic fertilizer and lime. The results showed that Cd content in different organs of rice at the maturity stage followed the order of root > stem > leaf > husk > brown rice. The application of lime could increase the soil pH. At the tillering stage, the soil pH significantly increased by 1.35 and 1.84 units under the treatment of low amount lime and high amount lime, respectively.The application of organic fertilizer could increase the organic matter content. Compared with the control, the content of organic matter increased by 6.60 g/kg at tillering stage and 2.72 g/kg at maturity stage in the treatment of high amount of organic fertilizer.The filling stage was an important period for the absorption and accumulation of Cd in rice. The application of lime and organic fertilizer could reduce the available Cd content in the soil during the filling stage.Compared with the control group, the content of available Cd in soil treated with high amount organic fertilizer and lime significantly decreased by 52.05% and 46.87%, respectively. Both organic fertilizer and lime could significantly reduce the Cd content of brown rice, and the effect of reducing Cd followed the order of high amount of organic fertilizer > high amount of lime > low amount of organic fertilizer > low amount of lime, the effect of high amount organic fertilizer treatment was the best, Cd content of brown rice decreased by 68.20%.