Impact assessment of nickel on chickpea and microbial activities in alluvial soil of Varanasi

Growth, yield and accumulation of Ni in chickpea (Cicer arietinum L.) as well as population & activities of soil microorganisms as influenced by Ni were studied with 0, 1.5, 3, 6 and 12 mg Ni kg⁻¹ of soil. Plant growth, nodulation and yield of grain and straw were increased at lower doses up to 3 mg Ni kg⁻¹ but decreased at higher doses. At higher level, accumulation of Ni in root was mostly two times greater than in grain. Population of bacteria, fungi and actinomycetes and evolution of CO₂ were drastically reduced by application of >3 mg Ni kg⁻¹. Inhibition of enzymatic activities was more pronounced in dehydrogenase than urease. Microbial cfu and activities progressively declined after ten days of incubation. Nickel @ 3 mg kg⁻¹ appeared to be sufficient for good harvest of chickpea.