Journal of Food, Agriculture and Environment

Super-optimal fertilization affects root growth and soil microbial abundance and biomass during wheat growth


Rajiv Rakshit 1,*, #, A.K. Patra 1, 2, T.J. Purakayastha 1, R.D. Singh 1, Himanshu Pathak 3, Shiva Dhar 4, Anupam Das #

Recieved Date: 2015-08-30, Accepted Date: 2015-12-20


A field experiment was conducted during 2010-2011 and 2011-2012 to investigate the effect of recommended 100% nitrogen, phosphorus and potassium (NPK) to super-optimal doses (200% NPK) of mineral fertilizers on root growth pattern, microbial biomass and counts, organic carbon and mineral nitrogen at various phenological stages of wheat growth. Super-optimal level of fertilizers (200% NPK) increased the root length density by 71.8% as compared to recommended dose of fertilizers in the surface layer (0-15 cm). There was positive effect of fertilizer addition on soil ammonium-N and nitrate-N contents. Excessive mineral fertilizer did not affect the soil organic carbon (SOC), but SOC was found to be higher at anthesis stage (16.67% and 12.32% higher over maturity and Crown Root Initiation (CRI) stage, respectively). Microbial biomass carbon (MBC) was found to be higher (252.06 µg g-1 dry soil) at anthesis stage of wheat growth, which declined to 213.28 µg g-1 dry soil at maturity. Super-optimal application of fertilizers led to significant increase in microbial biomass nitrogen (MBN) at anthesis (+17.7%) and maturity stage (+15.55%) over the 100% recommended dose of fertilizer. Data on microbial count (bacteria, fungi and actinomycetes) revealed a significant decrease in treatments receiving 175% NPK (-64.90% for bacteria, -38.78% for fungi and -16.41% for actinomycetes) as compared to 100% NPK.


Super-optimal fertilization, microbial biomass, microbial count, physiological stages

Journal: Journal of Food, Agriculture and Environment
Year: 2016
Volume: 14
Issue: 1
Category: Agriculture
Pages: 112-118

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