Evaluation of Greywater Irrigation Impact on Soil and Edible Crops

Abstract

Agriculture, a cornerstone of human sustenance, is facing unprecedented challenges in meeting the escalating global food demand. The world's population is projected to reach 9.7 billion by 2050, putting immense pressure on the agricultural sector to increase food production (FAO, 2017). Irrigation, a crucial component of modern agriculture, plays a vital role in ensuring crop yields, and its importance cannot be overstated. However, the increasing demand for freshwater resources has led to a significant depreciation in available freshwater resources, threatening the very foundation of global food security. This study investigates the potential of greywater utilization for irrigation as an alternative to fresh water, focusing on its effects on soil and crop performance. To examine the impact of greywater irrigation on soil and crop health, three crops i.e., coriander, spinach, and lettuce are considered. Conducted in Muzaffargarh City, characterized by predominantly hot weather with occasional cloudiness, the efficacy of greywater irrigation is explored as compared to tap water as control for comparison. There employed a controlled setup using no. of pots per crop type. The greywater applied is of 100%, 75%, 50%, 25% and 0% concentration. Greywater samples are collected from kitchen regularly for application. The various water quality tests, including electrical conductivity, calcium, magnesium, sodium, carbonate, bicarbonate, chloride, residual sodium carbonate, and sodium adsorption ratio are performed. Soil and crop samples are analyzed for total dissolved sodium, soil pH, organic matter content, available phosphorus, available potassium, soil saturation, and texture. Results indicate that greywater exhibits higher electrical conductivity and concentrations of calcium, magnesium, sodium, carbonate, bicarbonate, and chloride compared to tap water. However, greywater also contains residual sodium carbonate and demonstrates a higher sodium adsorption ratio. Soil analysis reveals an increase in total dissolved sodium levels post-irrigation with greywater, along with a decrease in soil pH. Moreover, greywater irrigation leads to an improvement in soil organic matter content. This study's findings will contribute to sustainable water management strategies, minimizing freshwater usage and preserving this valuable resource for other purposes.