Volume 11, Issue 24, July - December 2025

Assessment of sugar mill effluent discharge on soil physico-chemical attributes and its correlation with soil microbial biomass in paddy fields

Rahul Kumar Nigam, Prateek Singh, Jay Shankar Singh^♦

Department of Environmental Microbiology, Babasaheb Bhimrao Ambedkar University, Lucknow-226025, India

^♦Corresponding author
Jay Shankar Singh, Department of Environmental Microbiology, Babasaheb Bhimrao Ambedkar University, Lucknow-226025, India

ABSTRACT

The open discharge of untreated sugar mill effluent (SME) onto agricultural land and into water bodies is widely recognized as one of the most polluting ecological disturbances adversely affecting soil systems and microbial processes. Our findings provide novel insights into the impact of SME discharge on soil physio-chemical properties and their correlation with soil microbial biomass (SMB)-C, -N, and -P across three selected paddy fields adjacent to sugar mills in Uttar Pradesh, India. From each selected paddy field, soil samples were collected randomly in triplicate from a depth of 10-15 cm. ANOVA revealed statistically significant (P < 0.05) differences in soil physico-chemical attributes and SMB-C, -N, and -P levels across the experimental sites. The variations in soil physico-chemical properties and SMB-C, -N, and -P levels across the selected experimental paddy sites could be due to the variations in quantity and quality of discharged SME from different sugar mill industries to the soil. The SMB-C, -N, and -P levels were found to be comparatively higher in the paddy soil of the Haidergarh site than in the Ayodhya and Burhwal sites. The SMB-C, -N, and -P exhibited positive correlation with total C and total N, NH4+-N, NO3⁻-N, soil moisture, and soil porosity. In contrast, a negative correlation was found between bulk density (BD) and electrical conductivity, as well as SMB-C, - N, and -P, suggesting that a compact soil with higher BD and ions suppresses the levels of SMB. These findings indicate that SME discharge in paddy soils influences the soil physico-chemical characteristics, which in turn govern the SMB-C, -N, and -P levels, playing a crucial role in maintaining soil fertility and regulating soil nutrient availability to the paddy crop.

Keywords: Paddy, sugar mill effluent, soil microbial biomass, soil pollution, soil N.

Discovery Agriculture, 2025, 11, e15da3155

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Published: 14 September 2025