Impact of zeolite-sewage sludge blends and reduced nitrogen on soil carbon, nutrient dynamics, and rice growth response

Alluvial soils are abundant in natural soil nutrients, but the overuse of nitrogen fertilizers and the inappropriate use of nitrogen fertilizers lead to immobilizing conditions for soil nutrients and thereby reduce productivity. The present work discusses the possibility of using natural nanomaterial in order to improve the efficiency in nutrient use and also to overcome the adverse effects caused by the excessive application of fertilizers. In the present study, clinoptilolite zeolite and processed sewage sludge mixtures were applied alone or in combination with reduced levels of recommended nitrogen fertilizer. This experiment was conducted during year 2018-2020 under greenhouse condition. There were eight treatments with varied percentages of zeolite and sewage sludge, and their effectiveness in promoting increases in soil carbon pools, nutrient indicators, and plant growth responses was assessed. The results showed that a mixture of 50% dose of recommended N fertilizer, 4-6% zeolite, and 5-10% of sewage sludge considerably enhanced all growth parameters of the crop such as leaves, tillers, culms, and panicles and improved straw and grain yield. Addition of 6% zeolite along with sewage sludge had a positive impact on plant tillering capacity. Treatment 75% recommended N fertilizer dose combined with 4% zeolite and 5% sewage sludge positively influenced the plant height at 40th and 55th days after treatment. Treatment with 50% recommended N fertilizer dose, 6% zeolite, and 10% sewage sludge positively affected the carbon level along with other yield parameters in later stages. Principal component analysis significantly distinguished treatments with the inclusion of zeolite and sewage sludge based on responses drawn from plants. The combination of 6% zeolite and 10% sewage sludge, combined with a dose 50% recommended N fertilizer, was found to have a positive influence on the carbon fractions in the soil, nutrient levels, and the response of rice plants.