磷肥对砷污染土壤的植物修复效率的影响:田间实例研究

通过田间试验研究施用磷肥对砷超富集植物蜈蚣草(PterisvittataL.)生长和砷污染土壤修复效率的影响.结果表明,适量施用磷肥促进蜈蚣草的生长,显著提高其生物量,但过量施用磷肥对植物产量无贡献.随着磷肥施用量的增加,蜈蚣草地上部砷含量呈先增加后减少的趋势,理论上在施磷量为340kg·hm-2时,砷含量可达最高(1622mg·kg-1).磷的含量与施磷量呈极显著的正相关关系.施磷量为200kg·hm-2的砷累积量最高,是不施磷处理砷累积量的2 4倍及600kg·hm-2施磷量砷累积量的1 2倍.种植蜈蚣草7个月后,土壤总砷均有不同程度的下降,施磷量为200kg·hm-2的土壤中砷含量下降5 0mg·kg-1,土壤修复效率最高(7 84%).对照和600kg·hm-2施磷量处理的土壤修复效率分别为2 31%和6 63%.理论上达到最大土壤修复效率所需施磷量为369kg·hm-2.施用磷肥可以维持土壤有效态砷含量在蜈蚣草种植前后变化不大,保证蜈蚣草下个生育期对砷的吸收.这些结果说明施用磷肥是蜈蚣草等砷超富集植物在现场修复中的必要手段,优化施磷技术可大大提高砷污染土壤的修复效率.

Effect of application of P fertilizer on efficiency of As removal from As-contaminated soil using phytoremediation: Field study

Phytoremediation is a promising new technology that using hyperaccumulating plants to remove heavy metals. A field experiment was conducted to study the effect of P fertilizer on growth of and As accumulation in Pteris vittata L., an As-hyperaccumulator. Yields of P. vittata were enhanced with increasing P addition, however there was no further increase when rate of P addition was more than 200kg·hm^-2. Application of P fertilizer could enhance As concentration, and As concentration in the aboveground of P. vittata was depressed because of excessive P addition. Theoretically, As concentration of plant reaches a maximum of 1622mg·kg^-1 when rate of P addition is 340kg·hm^-2. There was a significantly positive relationship between rates of P addition and P concentrations in the aboveground. Plant treated with 200 kg(P)·hm^-2, accumulated 3.74 kg(As)·hm^-2 in its aboveground part, which was 2.4 times more than the control and 1.2 times more than that in plant treated with 600 kg (P)·hm^-2. After 7 months of the experiment, soil As concentrations were significantly reduced in all treatments at harvest compared to those before transplanting. When rate of P addition was 200kg·hm^-2, efficiency of As removal was the highest (7.84%), while efficiencies of As removal at control and 600 kg·hm^-2 treatments were 2.31% and 6.63%, respectively. The highest efficiency of As removal in theory could be achieved at 369kg·hm^-2 P addition. Moreover, the results also showed that P application was helpful to maintain a balance of available As between before transplanting and after harvest. Application of P fertilizer is necessary for phytoremediation using As-hyperaccumulator; and optimized P application could significantly enhance the efficiency of As removal from contaminated soils.