石灰、硅钙镁改良剂对不同土壤-水稻系统Cd吸收累积的影响

Effects of lime, silicon-calcium-magnesium amendments on Cd absorption and accumulation in different soil-rice systems

为研究改良剂(石灰、硅钙镁肥)对典型稻田土壤-水稻系统Cd吸收累积的影响,选取河沙泥(潮土母质发育)和紫泥田(紫色砂页岩母质发育)模拟制备成中度Cd污染土壤,施加不同用量的石灰和硅钙镁肥,进行水稻盆栽试验,分析土壤pH、土壤Cd形态以及水稻各部位Cd含量变化,探讨不同改良剂对不同土壤-水稻系统Cd吸收累积的影响.结果表明,施用石灰和硅钙镁肥能显著提高河沙泥土壤pH值,分别提高0.62-0.79个单位、0.35-0.46个单位,但对紫泥田pH值无显著影响.向河沙泥中施用石灰能降低其土壤酸提取态Cd含量,且在S3.0处理时降幅最大;而紫泥田施用硅钙镁肥能显著降低其酸提取态Cd.施用石灰和硅钙镁均能降低河沙泥水稻糙米Cd含量,分别降低23.5%-35.9%、9.5%-21.9%,且随着施用量的提高,糙米Cd含量降低幅度逐渐增大;施用硅钙镁肥能显著降低紫泥田糙米Cd含量,下降幅度为23.5%-34.1%.同种改良剂对水稻Cd吸收累积的影响因土壤类型不同而存在差异,向河沙泥中施用石灰和紫泥田中施用硅钙镁能最大程度抑制水稻对Cd的吸收累积,降低糙米Cd含量,提高稻米品质.

In order to investigate the effects of amendments(lime,silicon-calcium-magnesium fertilizer) on Cd absorption and accumulation in rice in typical paddy fields,pot experiments were conducted which selected alluvial sandy soil(developed from moisture soil parent materials) and purple clayey soil(developed from purple sand shale parent materials) to simulate and prepare soil samples with moderate Cd contamination.As well as different amounts of lime and silicon-calcium-magnesium fertilizer.The pH,soil Cd fractions and the Cd contents in various parts of rice,were analyzed and the effects of amendments on absorption and accumulation of Cd in different soil types were evaluated.The results showed that the application of lime and silicon-calcium-magnesium fertilizer significantly increased the soil pH in the alluvial sandy soil,which increased by 0.62 to 0.79 units and 0.35 to 0.46 units,respectively.But for the purple clayey soil,there was no significant effect on soil pH.The application of lime reduced the content of acid extractable fraction of Cd in the alluvial sandy soil,and the content was the lowest in S3.0 treatment;while the application of silicon-calcium-magnesium fertilizer significantly decreased acid extractable fraction of Cd in the purple clayey soil.Applying lime and silicon-calcium-magnesium fertilizer to the alluvial sandy soil reduced the Cd content of brown rice by 23.5% to 35.9% and 9.5% to 21.9%,respectively.And the Cd content of brown rice decreased gradually with the increase of application rates of the amendments.The application of silicon-calcium-magnesium fertilizer in the purple clayey soil reduced the Cd content of brown rice by 23.5% to 34.1%.The effect of the same kind of amendment on Cd absorption and accumulation in rice was different due to different soil types.Applying lime to the alluvial sandy soil and silicon-calcium-magnesium fertilizer to the purple clayey soil inhibited the absorption and accumulation of Cd in rice,reduced the Cd content of brown rice and improved the quality of rice.