Abstract

Author:
Md. Ibrahim Ali, M. H. Rahmana, Md. Mahamudul Hasan, M. M. Husain, K.S. Arefin, Alif Hossain, Mehedi Hassan, Shamim Akram, Md. Shah Abdullah Al Mamun

Doi: 10.26480/trab.01.2025.57.64

This is an open access article distributed under the Creative Commons Attribution License CC BY 4.0, which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited

To determine the impact of seaweed on boro rice productivity, a field study was conducted to assess various application rates of both raw seaweed (Caulerpa racemose) and its liquid extract. The initial trials took place during the 2021 Boro season at two locations: the BINA headquarters farm in Mymensingh and a site in Shyamnagor, Satkhira. The potency of these extracts is influenced by the seaweed species (such as brown, red, or green varieties), the method of extraction, and the environmental conditions during its growth cycle. Seaweed is notably high in chlorophylls, proteins, and sulfated polysaccharides. Application methods for crops are versatile, including foliar sprays and soil amendments. It can fundamentally alter a plant’s cellular respiration and introduce a range of growth-promoting hormones, including NAA, auxins, vitamins, and cytokinins. The study investigated two distinct factors: Basal Application: Processed seaweed was incorporated into the soil at six different rates: a control (no seaweed), 0.5, 0.625, 0.75, 0.875, and 1.0 tonne per hectare (t ha⁻¹). Foliar Spray: A liquid seaweed extract was sprayed during the active tillering stage at seven concentrations: a control, 0.5, 0.625, 0.75, 0.875, 1.0, and 1.25 liters per hectare (L ha⁻¹). The seaweed was harvested from the Bay of Bengal, then dried and processed for application. The liquid extract was diluted in water before being sprayed near the base of the rice plants at the tillering stage. The experiment was methodically arranged in a Randomized Complete Block Design (RCBD) with three replications, using 5 m × 4 m unit plots. Analysis of the results showed a significant positive response. The highest grain yield, 5.73 t ha⁻¹, was achieved with the basal application of 1.0 t ha⁻¹ of seaweed, closely followed by the 0.875 t ha⁻¹ treatment. For the foliar spray, the 1.0 L ha⁻¹ application rate produced a statistically significant yield of 5.38 t ha⁻¹, with the 0.75 L ha⁻¹ rate being the next most effective. Using seaweed extract on rice demonstrably enhances growth, grain production, and biological yield, while also improving the nutrient content of the grain. This boost in productivity is linked to an increased number of tillers, greater spikelet fertility, and fewer unfilled grains. These findings underscore that both the method of application and the specific dosage of seaweed are critical factors in maximizing the yield of boro rice.