Yield and trace metal levels in colocasia (Colocasia esculenta L.)-potato (Solanum tuberosum L.) cropping sequence as influence by fly ash and fertilizer application

Experiments were conducted to see the effect of fly ash on growth, yield and quality of two tuber crops cropping sequence Colocasia and potato in red and lateritic soil of Chotanagpur Plateau. Result revealed a positive and significant effect of 4, 8 and 16 percent fly ash (w/w) incorporation in acidic soil (pH 5.9) on crop yield and on all growth attributes of both the tested vegetable crops. Tuber yield of Colocasia was recorded as 4.96, 5.66 and 6.95 t ha-1, respectively due to application of 4, 8 and 16% fly ash alone. Yield of Colocasia drastically increased over control and found higher (11.92 t ha-1) at 16% FA+NPK followed by 10.25 t ha-1 yield of Colocasia with 8% FA+NPK. Potato yield (22.39 t ha-1) was higher in 16% FA+NPK treatment followed by yield 20.63 t ha-1 at 8% FA+NPK applied treatment when grown on residual fly ash application. In control plot Pb, Co and Ni content were found 13.9, 15.2 and 5.0 mg kg-1, while at 16% fly ash application level, Pb, Co and Ni content were found 28.7, 35.6 and 15.7 mg kg-1, respectively in edible part of Colocasia (cormel). Fe (310 mg kg-1), Mn (28 mg kg-1), Zn (46.7 mg kg-1), Cu (35.8 mg kg-1), Pb (22.0 mg kg-1), Ni (20.9 mg kg-1) and Co (27.0 mg kg-1) content were higher in potato tuber, when grown on 16% residual fly ash in Colocasia-potato cropping sequence.