Effect of Sewage sludge and fertilizers application on accumulation of heavy metals and yield of Indian mustard (Brassica juncea L.)

Abstract

A pot experiment was conducted in net house during Rabi 2016-17 at Institute of Agricultural Sciences, Banaras Hindu
University, Varanasi to find out the effect of Zinc, Boron, Sulphur and Sewage Sludge application on heavy metal
accumulation in soil and plants of mustard [Brassica juncea (L.) Czern & Coss.] and its yield. To conduct the pot
experiment, bulk soil samples (0-15 cm depth) were collected from the Agricultural Research Farm, Banaras Hindu
University, Varanasi. Altogether, twelve treatments consisting of combinations of sewage sludge and chemical fertilizers,
S, Zn, B, along with a control were used for pot experiment. The experiment was laid out in a completely randomized
design (CRD) with three replications. The results showed that due to application of different levels of boron, zinc,
sulphur and sewage sludge in mustard crop, a significant increase in grain and stover yield was obtained.The maximum
seed and stover yields (20.9 and 60.5 g pot-1) were found in treatment T10 that were 82.9 % and 69.4 % higher in
comparison to control, and was accompanied by T12 with 19.1 and 55.8 g pot-1, respectively. But both were found
statistically at par with each other.The combined application of sewage sludge and inorganic fertilization also enhanced
the accumulation of heavy metals in soil and mustard plant (Ni, Pb, Cd and Cr) particularly at higher rates of sludge
application. The maximum content of Ni, Pb, Cd and Cr in mustard seed (13.7, 2.5, 1.57 & 0.92 mg kg-1 ) and stover (14.7,
2.5, 1.97 and 2.2 mg kg-1 ) as well as in post harvest soil were found under T10 (100% RDF + SS @ 20 t ha-1) which was
accompanied in the order of T9, T12 and T11 treatments.