Varied effects of untreated textile wastewater onto soil carbon mineralization and associated biochemical properties of a dryland agricultural soil.
Wastewater is an alternative, valuable and cost effective resource for irrigation in water-scarce arid and sami-arid regions of the world including Pakistan. Soils near urban centers are cultivated for vegetable and cash crops using untreated wastewater. Current study was performed with objectives of assessing impacts of untreated textile wastewater on some soil chemical, biological and enzymatic activities. The microcosm incubation study used a clay loam soil that received 0 (distilled-water), 25, 50 and 100% wastewater concentrations and incubated for 30 and 60 days under optimum temperature and moisture conditions. Soil respiration was measured periodically throughout the experiment over 60 days. After the incubation periods of 30- and 60-d, soils were destructively analyzed for pH, electrical conductivity (EC), water extractable organic matter (WEOM), microbial biomass carbon (MBC), microbial metabolic quotient (qCO2) and dehydrogenase enzymatic activity. Results revealed that wastewater and incubation time significantly altered chemical, biological and enzymatic properties of soils. The observed large surge in soil respiration, at initial stage, was stimulated by dissolved organic matter in wastewater. Dehydrogenase activity increased significantly with increasing wastewater concentrations. Increase in qCO2with wastewater concentration and incubation time suggested more stress to microorganisms but also enhanced microbial activity under stress to synthesize biomass. We found significant positive (R2= 0.64, p < 0.001) relationship between soil respiration and MBC, however, correlation between WEOM and MBC was significant negative (R2= 0.18, p < 0.01) indicating a dynamic mismatch between carbon substrate, soil respiration and buildup of MBC pool. Wastewater concentration and incubation time interaction had significant (p < 0.01) effect on WEOM suggesting that WEOM accumulated over time and comparatively less utilized by microorganisms. Short- and long-term effects of untreated wastewater on soil physico-chemical and biological health should be assessed before its use for crop production.
Department of Environmental Sciences & Engineering, Government College University Faisalabad, 38000, Faisalabad, Pakistan.
Mahnaz
M
Roohi
Department of Environmental Sciences & Engineering, Government College University Faisalabad, 38000, Faisalabad, Pakistan. Electronic address: mr548@ymail.com.
Muhammad
M
Riaz
Department of Environmental Sciences & Engineering, Government College University Faisalabad, 38000, Faisalabad, Pakistan.
Muhammad Saleem
MS
Arif
Department of Soil & Environmental Sciences, University College of Agriculture, University of Sargodha, Pakistan.
Sher Muhammad
SM
Shahzad
Department of Environmental Sciences & Engineering, Government College University Faisalabad, 38000, Faisalabad, Pakistan.
Tahira
T
Yasmeen
Soil Science Division, Nuclear Institute for Agriculture and Biology (NIAB), Jhang Road, Faisalabad, Pakistan.
Muhammad Atif
MA
Riaz
Soil Science Division, Nuclear Institute for Agriculture and Biology (NIAB), Jhang Road, Faisalabad, Pakistan.
Shermeen
S
Tahir
Soil Science Division, Nuclear Institute for Agriculture and Biology (NIAB), Jhang Road, Faisalabad, Pakistan.
Khalid
K
Mahmood
D000383:Agriculture / Q000379:methods; D018533:Biomass; D002244:Carbon / Q000032:analysis / Q000737:chemistry*; D002245:Carbon Dioxide / Q000378:metabolism; D057965:Carbon Sequestration; D004553:Electric Conductivity; D006863:Hydrogen-Ion Concentration; D010088:Oxidoreductases / Q000378:metabolism; D010154:Pakistan; D012987:Soil / Q000737:chemistry*; D012988:Soil Microbiology; D013696:Temperature; D013783:Textile Industry; D014865:Waste Disposal, Fluid / Q000379:methods; D062065:Wastewater / Q000737:chemistry
D002244:Carbon; D002245:Carbon Dioxide; D010088:Oxidoreductases; D012987:Soil; D062065:Wastewater
Soil enzymes; Soil microbial activity; Soil respiration; Textile wastewater; Water extractable organic carbon