Survival of Rhtzobium Leguminosarum in Soils Collected from Farmer's Field Receiving Sewage Water/Industrial Effluents

摘要

Sewage water application to agricultural lands is often the most economical way of disposal and can be beneficial by increasing the organic matter contents and plant nutrients of the soil, or can be harmful as sewage water from industrial areas often contain considerable amount of potentially toxic metals such as Cu, Zn, Ni, Cd, Pb and Cr. To assess the situation in Haryana state, soil samples from 14 such locations in Haryana were collected and in these soils contents of heavy metals and survival of two Rhizoblum leguminosarum strains of biovar viciae (PRH 1) and biovar trifolii (B 48) tagged with GFP was determined. The total metal contents of Cd, Cu, Zn and Ni in the soil samples ranged between 1.33-6.66 mg kg~(-1); 55.8-353.18 mg kg~(-1); 356-1028 mg kg~(-1) and 90-199.7 mg kg~(-1) of soil respectively. In Rohtak 1 soil levels of Cd, Cu and Zn were highest while Ni was highest in Sonipat 2 soil. The availability of Cd, Cu, Zn and Ni in these soils ranged from 1-29.3; 6.2-47; 2.4-13.5 and 2-9 per cent of their total contents respectively. Rhizobia population was monitored up to 45 days. The survival of rhizobia in different samples receiving sewage water decreased up to 30 days and thereafter was stabilized. In Hisar 1 soil the rhizobia were not detected after 5 or 10 days of addition. The reduction in viable cell count in Rohtak soils was to the extent of 78-97 per cent. Available Cd contents in the soils affected the survival of R. leguminosarum and reduction was significant in case of R, leguminosarum biovar trifolii.