Synergistic Effects of Sewage Sludge and Carbon-Based Composite Fertilizer on Growth, Yield, and Soil Health in Rice (Oryza sativa)

Abstract

The management of sewage sludge (SS), a nutrient-rich byproduct of wastewater treatment, presents a significant challenge and opportunity for sustainable agriculture. Utilizing SS on cultivated land offers an environmentally friendly alternative to storage or incineration, supporting a circular economy. This study, conducted in a wire-house facility at the University of Agriculture Faisalabad's Institute of Soil and Environmental Sciences (ISES), investigated the effects of SS and carbon-based composite fertilizer (CBCF) on the growth and yield of rice (Oryza sativa). A pot experiment arranged in a Completely Randomized Design (CRD) with three replications evaluated two application rates of SS (1% and 2%) and CBCF (0.25% and 0.5%) under standard irrigation regimes. Data were collected on key agronomic parameters, including shoot length, fresh and dry biomass of shoots and roots, hundred-grain weight, and post-harvest soil properties like electrical conductivity (EC) and sodium adsorption ratio (SAR). Analysis of variance (ANOVA) revealed that while yield was affected by irrigation levels, the application of soil amendments significantly enhanced plant growth. Specifically, the 2% SS treatment was more effective than 1% in promoting shoot and root length. The combination of 2% SS and 0.5% CBCF, which provided a higher organic matter content, was particularly effective, suggesting that the addition of these organic amendments can be a promising strategy for mitigating the adverse effects of soil salinity and water stress, thereby improving crop productivity.