Abstract

Effect Of Biofertilizer And Dairy Waste On Growth Response And Removal Of Arsenic From Soil Using Vetiveria Zizanioides

Author(s): S.K.Singh, Asha A.Juwarkar, J.Meshram

Phytoextraction can provide an effective in situ technique for removing heavy metals from polluted soils. The study reported in this paper was undertaken to evaluate the growth response of Vetiveria zizanioides in arsenic (As) contaminated soils and its ability to remove As. The plant has been recently identified to be tolerant to high As concentration and have great potential in remediating As contaminated soils. This has been demonstrated by conducting pot culture experiment. The soil spiked with different levels of As i.e. 0, 500, 1000, 1500 and 2000 mg kg-1 was amended with organic amendments like dairy waste, mycorrhizae and biofertilizer (Azotobacter) and another set without amendments was also kept for comparison to assess the effect of amendments on arsenic removal. The plants were harvested after six months and their growth and As accumulation in roots and shoots were estimated. The results from this study indicate that the plant exhibited high tolerance to As toxicity in the soils and normal growth was attained upto 500 mg kg-1 when amended with dairy waste, mycorrhizae and Azotobacter. The plant was not survived at 500 mg kg-1 without amendments. This indicate that the soil amendments invoked greater root growth and enhanced the phytoextraction process relative to all other treatments. At higher concentrations viz. 1000, 1500 and 2000 mg kg-1 with and without amendments, the plant was not survived. The accumulation of As was much greater in roots (185.4 mg kg-1) than in shoots (100.6 mg kg-1). The As level in the polluted soil was reduced from 500 mg kg-1 to 214 mg kg-1 after six months. The removal of As level in the rhizosphere was found to be 57%. Microbial population was not affected in the As contaminated soil amended with dairy sludge, mycorrhizae and Azotobacter. These results indicate that Vetiveria zizanioides could possibly be used with success for removal of As from contaminated soils.