Seasonal variations in irrigation water quality induce differential physiological and biochemical responses in sugarcane (Saccharum officinarum L.)

Abstract

The issue of water scarcity in Pakistan is a significant challenge which is due to exacerbated population growth as well as increase in freshwater demand. The application of wastewater for irrigation, especially in semi-urban regions, can indeed be a practical solution due to its ready availability and affordability. While wastewater can serve as a valuable resource in water-scarce regions, its use must be carefully managed to minimize potential risks to plant health, soil fertility, and human well-being. A study was conducted aiming to assess the seasonal changes in physicochemical properties of irrigated wastewater and their influence on morphological, physiological and biochemical responses of sugarcane (Saccharum officinarum L.). Sugarcane plants were grown for consecutive two years in peri-urban agricultural areas near the water channels. Sugarcane plants were grown in two different fields and irrigation of the crop was done with wastewater and freshwater, respectively. Water (wastewater and freshwater) and plant samples were collected four times in a year in different seasons (winter, spring, summer, fall) for two consecutive years (2016-2017). All the collected data had been subjected to multivariate analysis of variance (MANOVA) for assessing the impact of seasonal variation on plant responses under the influence of irrigated wastewater. The findings from the study highlighted the complex relationship between wastewater irrigation and the physiological responses of sugarcane plants. The observed increase in antioxidant activities of wastewater irrigated plants compared to freshwater irrigated plants suggested that sugarcane may undergo biochemical adjustments to cope with the stress induced by the contaminants present in the wastewater. Moreover, the significant differences in plant mineral contents across different seasons were observed which indicated the dynamic nature of nutrient availability in the irrigation water and its impact on plant growth and development. We concluded that wastewater irrigation can affect the potential output of the agriculture sector by altering plant physiology which underscores the importance of considering the quality of irrigation water in agricultural practices. For future prospectives, the study can be extended to other crops to develop comprehensive strategies for sustainable agriculture.