IMPACT ASSESSMENT OF WASTEWATER IRRIGATION ON SOILS AND CROPS IN PERI-URBAN AREA OF NAGPUR.
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Date
2019-12-03
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Dr. Panjabrao Deshmukh Krishi Vidyapeeth, Akola, Maharashtra.
Abstract
The wastewater of Nagpur city discharged into Nag River is utilized for irrigating vegetables and other agricultural crops without giving due consideration to soil, plant and human health. Therefore, the study was conducted to see impact of wastewater irrigation on soils and crops in peri-urban area of Nagpur.
The wastewater and soil samples were collected from five different villages from the farmers’ fields in Kamptee and Kuhi talukas of Nagpur district where the wastewater is continuously used for irrigation over the years. For reference (control), well water and soil under well water irrigation were also collected from nearby area of each selected wastewater sites. The samples of different crops were collected from the fields irrigated with wastewater and well water.
The pH of wastewater was in the range of 7.18-7.60 with higher EC (0.64-0.85 dSm-1), low BOD (10.98-27.88 mgL-1) and COD (25.25-60.23 mgL-1). The concentration of HCO3-, Cl-, SO42-, Mg2+, Na+, K+, total hardness, micronutrients (Fe, Mn, Cu and Zn) and heavy metals (Cd, Cr, Pb and Co) in wastewater was higher than that of well water. The concentration of trace elements like Mn, Cu, Cd, Cr and Co in wastewater was higher than the recommended safe limit hence wastewater use in agriculture indicating chances of toxicity hazards to soil and plant.
The soils under long term use of wastewater irrigation showed relatively lower bulk density (1.27-1.33 Mg m-3) and saturated hydraulic conductivity (1.40-1.48 cm h-1). The wastewater irrigated soils showed slightly lower reaction (pH 7.33-7.60) with higher EC (0.70-0.84 dSm-1), high organic carbon (5.41-5.53 g kg-1). The available N, P, K status of wastewater irrigated soils was appreciably higher as compared to those in the well water irrigated soils. The concentration of Fe, Mn, Zn, Cu, Cd, Cr, Pb and Co was comparatively higher in wastewater irrigated soils and found above recommended safe limit. The concentration of these elements was observed to be approaching their critical concentration and may lead to soil contamination in near future if the same levels of wastewater are applied on these soils.
The concentration of micronutrients (Fe, Mn, Zn and Cu) and heavy metals (Cd, Cr, Pb and Co) in wastewater irrigated crops like wheat, chickpea and spinach was higher than that of well water irrigation.
Thus, it can be concluded that the long-term use of wastewater for irrigating agricultural crops was beneficial in improving soil chemical properties like organic carbon, available N, P and K, micronutrients (Fe, Mn, Zn and Cu). However, higher concentration of bicarbonates, chlorides, sodium and potassium and heavy metals (Cd, Cr, Pb and Co) in wastewater showed considerable contamination of soil and plant which may enter in the food chain hence the continuous use of wastewater in agriculture for irrigation should be done cautiously.
Description
Present research deals with the impact of wastewater irrigation on soils and crops in peri-urban area of Nagpur. Five villages viz., Pawangaon, Kem, Adaka, Titur and Chitapur from Kuhi and Kamptee talukas of Nagpur district were selected. Accordingly the wastewater, well water, soil and plant samples were collected and analyzed for physico-chemical properties, micronutrients and heavy metals accumulation as per standards methods.
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Citation
PANGUL, CHETAN SURESH. (2019). Impact assessment of wastewater irrigation on soils and crops in peri-urban area of Nagpur. Department of Soil and Water Conservation Engineering (Agricultural Engineering), Dr. Panjabrao Deshmukh Krishi Vidyapeeth, Akola. M. Tech. 2019. Print. xvi, 136p. (Unpublished).