Phytostabilization of mine waste: growth and physiological responses of Vigna unguiculata (L.) Walp

Greenhouse experiments were carried out for phytoremediation of the Pb/Zn abandoned tailings (pH 3.2 and high metal content) of Rampura-Agucha Mines, Rajasthan. Vigna unguiculata (L.) Walp. (cowpea) was chosen as a test crop. On unamended tailings, the seeds of the test plant showed no germination. The tailing was amended with lime (3% on weight basis), 3% lime + NPK (diammonium phosphate at 60 kg/ha, muriate of potash at 40 kg/ ha) and 3% lime + FYM at 15 t/ha and used for experiments. Quantification of various parameters viz. shoot-root length, shoot-root dry weight, chlorophyll contents (a', 'b' and total) and peroxidase activity of test crop revealed T+ S + 3% lime + NPK to be the most suitable amelioration followed by FYM. The above treatments helped in improving the growth and productivity of the test plants by providing a favorable environment.