粉煤灰与煤矸石配比对苜蓿植株生长及其修复效果的影响

Effects of Different Proportion of Coal Ash and Gangue on Plant Growth and Bioremediation Effect of Medicago sativa

为探明苜蓿对煤矸石和粉煤灰栽培基质的修复效果,采用盆栽法,研究了粉煤灰与煤矸石不同配比对紫花苜蓿生长及基质p H值和电导率(EC)的影响。结果表明:T4∶6处理(下标数字表示粉煤灰与煤矸石质量比,下同)的苜蓿地上部、根系干质量最大,分别是T2∶8、T3∶7、T5∶5处理的1.24~2.73倍、1.30~1.98倍,植株地上部吸收N、P量也明显高于T2∶8、T3∶7、T5∶5处理,分别是其他处理的1.33~3.23倍、1.16~3.66倍;粉煤比对苜蓿地上部铜(Cu)、镉(Cd)吸收量有显著影响,T3∶7、T4∶6、T5∶5处理的Cu、Cd吸收量分别是T2∶8处理的2.47~3.42倍、1.75~2.46倍;T4∶6处理基质p H值接近中性,EC值较小,盐化程度较低,植物修复效果较好。研究表明,修复效果最佳的粉煤比为4∶6。

To explore the effects of phytoremediation on gangue and coal ash resulted from coal mining and using waste ,the effects of different ratios of coal ash and coal gangue mixed substrates on the growth of alfalfa（Medicago sativa） and pH,EC of substrates after planting in pot were studied. The results showed that the growth of alfalfa of T4：6 （ subscript numbers represented the mass ratio of coal ash to gangue, the same below） treatment was the best, and the aerial part and root dry weights of plants were significantly higher than T2：8 ,T3：7 ,T5：5 treatments,and reached 1.24--2.73 times and 1.30--1.98 times that of other treatments,respectively. Shoot nitrogen and phosphorus contents of T4：6 treatment were also significantly higher than other treatments, and reached 1. 33--3. 23 times and 1. 16--3. 66 times that of other treatments,respectively. The ratio of coal ash to gangue had significant effects on the uptake of Cu and Cd by the aerial part of alfalfa,and the amount of Cu and Cd absorbed by T3：7 ,T4：6 and T5：5 treatments were 2.47--3.42 times and 1.75--2.46 times that of T2：8 treatment, respectively. The pH of the T,6 treatment substrate after planting alfalfa was close to neutralization, and EC was smaller, indicating that its phytoremediation effect was better. Therefore,the substrate in the ratio of 4：6 was more helpful for the growth of Medicago sativa,and it could be the optimal ratio in phytoremediation of coal gangue and coal ash.