Elucidating distinct oxidative stress management, nutrient acquisition and yield responses of Pisum sativum L. fertigated with diluted and treated wastewater

Fertigation of crops with untreated wastewater predominates in developing countries. Use of wastewater for crop irrigation poses a potential risk of food chain poisoning with toxicants. However, direct and indirect interaction of wastewater with soil properties and crop productivity has been rarely investigated. The current work was, therefore, planned to quantify the impact of canal water, biologically treated and untreated wastewater on soil properties, growth, biochemical, nutrient turnover and yield of pea (Pisum sativum L.) plants. Seeds of P. sativum were sown in soil filled pots irrigated with five different water types [canal water (CW), biologically treated wastewater (BTW), 50%, 75% and 100% wastewater (WW50, WW75 and WW100)]. The plant samples were collected after 35 days for biochemical analysis, while yield parameters were recorded at maturity. The results revealed a significantly higher growth and yield of pea plants irrigated with BTW followed by WW50 and CW irrigated plants as compared to other wastewater treatment types. Application of untreated wastewater (WW75 and WW100) resulted in stunted growth due to decrease in total chlorophylls, carotenoids, activities of SOD and POD enzymes, and increase in lipid peroxidation (MDA and H2O2) as compared to CW, BTW, and WW50. Pre and post-harvest soil analysis revealed that application of concentrated wastewater caused soil alkalinization and subsequently limited the nutrient absorption by P. sativum plants. Growth enhancement of P. sativum under BTW might be a direct consequence of balanced accumulation of nutrients owing to alteration of soil properties. It was concluded that wastewater must be treated biologically or diluted with 50% of fresh canal water before application to agricultural fields in order to maintain soil nutrient level and sustainable crop productivity in the areas with less availability of fresh canal water.

Automated summary

The study found that irrigation with biologically treated wastewater significantly increased growth and yield of pea plants, while untreated wastewater led to stunted plant growth. Application of wastewater may cause soil alkalinization and limit nutrient absorption. Therefore, wastewater should be biologically treated or diluted before application to maintain soil nutrient levels.