Impact of sewage water irrigation on agricultural soil

Abstract

The rapidly increasing population growth and the steady increase in water requirements for agricultural and industrial development have placed severe stress on the water resources available and the long term use of sewage water for irrigation highly affects soil properties. In this study soil samples were collected from a cauliflower field prior and after sewage water irrigation, and the impact of sewage water irrigation on physical, chemical, and biological properties of soil was compared. For this, tested were pH, Electrical Conductivity (EC), Organic Carbon, available Nitrogen, Phosphorus, Potassium, Calcium, Magnesium, Zinc, Iron, Copper, Manganese, and microbial activity. Soil microbial biomass carbon, basal soil respiration, total viable count of bacteria, coliform population, Pseudomonas species, and Azotobacter significantly increased after sewage water irrigation as compared to prior to irrigation. Nevertheless, the bulk density and Rhizobium species of the soil flooded with sewage water was decreased relative to the same characteristics prior to irrigation. Cauliflower yield was significantly increased when sewage water flooded field as compared to the tube well water flooded field (i.e., water delivered via an iron pipe). Escherichia coli contamination was greater in sewage water and groundwater that can pose health risks for the nearby communities, to farmers and consumer of farm products. Hence, the efficient use of sewage and municipal wastewater successfully increase water resource for irrigation and may help in expanding agricultural production. But excessive use of sewage water may also affect the soil flora and fertility.