中性污染稻田淹水配施硫化物对降低糙米Cd积累的效果

摘要

In order to explore the measures to reduce the Cd content of grown rice in neutral polluted soil,a pot experiment was carried out to test the effects of flooding and sulfur compounds on Cd accumulation in the rice plants.The experiment was set up with six treatments,ie,conventional management,long-term flooding,long-term flooding + addition of 0.1% sodium sulfide,long-term flooding + addition of 0.1% sodium hydrosulfide,long-term flooding + addition of 0. 1% potassium sulfide,and long term flooding + addition of 0.1% calcium sulfate,and run for 3 season plantations of rice-vegetable-rice.The content of active Cd in the soil and the accumulation of Cd in rice and vegetables were observed.The effects of different sulfur compounds on Cd contents in brown rice were characterized.The results showed that long-term flooding could significantly reduce the level of available Cd in the soil and the content of Cd in brown rice,as compared with the conventional management.Treatments with long-term flooding + addition of 0.1% sodium sulfide,and long-term flooding + addition of 0.1% sodium hydrosulfide decreased 38.24% ~50.00% of Cd content in brown rice as compared with the long-term flooding.However,there was no significant difference in Cd content of brown rice between long term flooding + addition of 0.1% calcium sulfate and long-term flooding treatment.Soil water-logging treatment during the rice grow th period had no significant effect on Cd accumulation in the succeeding vegetable crop.But addition of sodium sulfide, sodium hydrosulfide,or potassium sulfide during the rice growth period still had significant reducing effects of cadmium accumulation on the following vegetable crops.Controlling the water soluble cadmium and the available Cd in the soil is the main reason for the reduction of Cd accumulation in brown rice.%为探讨降低中性重金属污染土壤上生长的水稻糙米Cd的途径,设置6个处理(常规管理、长期淹水、长期淹水+添加0.1% Na2S、长期淹水+添加0.1% NaHS、长期淹水+添加0.1% K2S和长期淹水+添加0.1% CaSO4)开展水稻-蔬菜-水稻3季盆栽试验,观察土壤中活性Cd水平和水稻与蔬菜中Cd的积累情况,分析长期淹水种植与配施不同硫化物降低糙米Cd含量的效果.结果表明,与常规管理比较,长期淹水种植水稻可显著降低土壤中有效态Cd水平和糙米中Cd的含量.长期淹水+添加0.1% Na2S、长期淹水+添加0.1% NaHS、长期淹水+添加0.1% K2S比长期淹水处理降低糙米中Cd含量达38.24% ~50.00%.但添加0.1% CaSO4对降低糙米中Cd的效果不明显.水稻生长期间的淹水处理对后茬蔬菜中镉积累影响不明显,但施用的Na2S、NaHS和K2S对降低后茬蔬菜中镉积累仍有显著的后效.土壤分析结果表明,控制土壤中水溶性Cd和有效Cd水平是降低糙米Cd积累的主要原因.