Autotoxicity of Rice Straw Extract on Germination, Growth, and Yield of Rice (Oryza sativa L.)

Abstract

Rice is a major global staple, but its cultivation faces weed challenges, prompting herbicide use that harms the environment. Rice straw contains allelopathic compounds with bioherbicidal potential, yet these substances may also cause autotoxic effects on rice, impacting its growth and productivity. This study was conducted to assess the autotoxic effects of rice straw (Oryza sativa L.) extract on rice seed germination, plant growth, and yield, as well as to identify the concentration level that effectively inhibited these processes.  The experiment took place at the Agronomy Laboratory and Greenhouse, Department of Crop Production, Faculty of Agriculture, University of Bengkulu, Indonesia from November 2024 to March 2025. A Completely Randomized Design (CRD) with a single factor was applied, involving five extract concentrations (0%, 2.5%, 5%, 7.5%, and 10%) and five replications. The observed variables included germination parameters such as radicle and plumule length, dry weight, and percentage of abnormal seedlings, along with growth and yield components such as plant height, leaf number, number of productive tillers, leaf length and width, panicle length, root and shoot dry weight, and 1000 grain weight. The study demonstrated that rice straw extract markedly suppressed seed germination and vegetative growth, while also diminishing rice yield. The highest inhibitory effect was observed at the 10% concentration, which led to a greater proportion of abnormal seedlings, shorter radicle length, and reduced dry weights of both radicles and plumules. Among the parameters analyzed, the percentage of abnormal seedlings exhibited the lowest Inhibition Concentration 50% (IC₅₀) value (4.35%), highlighting the heightened sensitivity of early plant development to allelopathic compounds in rice straw. These findings indicate rice straw has strong autotoxic properties, offering potential as an eco-friendly bioherbicide. However, proper management of rice straw waste is essential to minimize its adverse effects on crop yields. These findings highlight the potential of rice straw extract as an eco-friendly input that supports sustainable rice cultivation and promotes the proper utilization of agricultural residues.