Extended Abstract
Background and Objective: Rice is considered one of the most important staple foods worldwide, and ensuring adequate nutrition is essential to prevent yield reduction. Given its central role in the global food basket, the demand for rice continues to rise steadily. Therefore, identifying scientific and practical strategies to enhance rice production—especially in response to rapid population growth—is crucial. This study was conducted to investigate the effects of foliar application of seaweed extract and NPK chemical fertilizer on rice yield and its components.
Materials and Methods: This study was conducted during the 2023–2024 growing season at Sari Agricultural Sciences and Natural Resources University, using a split-plot design arranged in a randomized complete block design (RCBD) with three replications. The main plot treatments consisted of different concentrations (0, 2/1000, and 4/1000) of seaweed extracts from Ascophyllum nodosum and Ecklonia maxima. The subplot treatments included varying concentrations (0, 2/1000, 4/1000, and 6/1000) of two chemical fertilizers: 20-20-20 and 12-12-36 (NPK). Foliar application of the seaweed extract and chemical fertilizer was carried out at key physiological stages: stem elongation, flowering, and the grain dough stage. In this study, the following traits were measured: seed yield, straw yield, biomass yield, harvest index, panicle length, plant height, number of effective tillers per hill, number of filled and unfilled seeds, and thousand-seed weight.
Results: The results revealed that the simple effects of fertilizer and seaweed foliar application, as well as their interactions, had a significant impact on rice yield and its components. The highest seed yield was obtained from the treatment with a 4/1000 concentration of Ascophyllum nodosum combined with a 6/1000 concentration of (12-12-36) fertilizer (6314.1 kg/ha), which represented a 71.49% increase compared to the control. Straw yield increased by 67.44% with the 4/1000 concentration of Ascophyllum nodosum compared to the control treatment. The maximum values for thousand-grain weight and biomass yield were observed with the 4/1000 concentration of Ascophyllum nodosum in combination with the 2/1000 and 6/1000 concentrations of (12-12-36) fertilizer, respectively. These represented an increase of 8.33% and 70.52% compared to the control, respectively. The highest number of filled grains per panicle was associated with the treatment combining the 4/1000 concentration of Ascophyllum nodosum and the 4/1000 concentration of (12-12-36) fertilizer.
Conclusion: The combined application of seaweed extract and chemical fertilizer increased seed and biomass yield. The highest straw yield was associated with the 4/1000 concentration of Ascophyllum nodosum seaweed; however, foliar application of chemical fertilizer alone did not result in a significant increase in straw yield. Therefore, this study found that the application of Ascophyllum nodosum extract at an appropriate concentration, alongside a high-potassium fertilizer, had the greatest impact on enhancing yield and improving yield components. The seaweed Ascophyllum nodosum demonstrated superior results compared to Ecklonia maxima, suggesting its potential as a nutritional supplement for promoting rice growth in the paddy fields of northern Iran. |