Study on the Effects of Sea Weed Liquid Fertilizer Caulerpa racemosa on the Germination and Growth of Vigna unguiculata subsp. sesquipedalis

Abstract

Seaweeds are good marine resources that have been known to have agricultural uses especially as natural biostimulants in the form of Seaweed Liquid Fertilizers (SLF). The current paper examines the impact of SLF extract of a green alga, Caulerpa racemosa on germination and early growth of Vigna unguiculata subsp. sesquipedalis (asparagus bean). The extraction of SFL was done under the standard procedures and five percentages (1, 2, 3, 4, and 5) of SFL was applied to certified seeds in the presence of distilled water that acted as the control. It was measured in terms of germination percentage, radicle and hypocotyl length, seedling length, vigor index, growth index, phytotoxicity, phytomass and productivity at 15 days period. The findings indicated that the seeds with lower or moderate concentration of SLF especially 2% 3% and 5% had higher germination (up to 100 percent), radicle length (maximum 3.9 cm at 3 percent) and seedling vigor and growth index, of which the treatment at 3 percent had the greatest overall change. By comparison, the 4% concentration produced low germination and growth parameters. The seedlings that were treated with 3 percent SLF had the highest phytomass and productivity. In general, the results suggest that C. racemosa-based SLF in the optimal level can be successfully used to induce germination and early seedling growth in asparagus bean, which evidences the potential of this substance as an alternative to chemical fertilizers in cultivating legumes.

Introduction

The overuse of synthetic chemical fertilizers in modern agriculture has boosted crop yields but caused significant environmental damage, including soil degradation, water pollution, and greenhouse gas emissions. To address these concerns, natural biostimulants like seaweed liquid fertilizers (SLF) are being explored as sustainable alternatives. Seaweeds, rich in bioactive compounds such as plant growth hormones, vitamins, amino acids, and micronutrients, enhance plant growth, stress resilience, and soil moisture retention.

This study examined the effects of SLF prepared from Caulerpa racemosa on the growth, germination, and productivity of Vigna unguiculata subsp. sesquipedalis (asparagus bean). Different concentrations (1–5%) of the extract were tested, with 2–3% showing the best results in terms of germination rate, radicle and hypocotyl growth, seedling length, vigor index, phytomass, and productivity. Higher concentrations (4–5%) were less effective or inhibitory, indicating the importance of optimizing application rates.

The positive effects of 2–3% SLF are attributed to the bioactive compounds promoting cell division, nutrient absorption, metabolic activity, and moisture retention. Overall, C. racemosa SLF proved to be an effective, eco-friendly biostimulant, showing potential for sustainable legume cultivation. Future work should focus on long-term field trials, nutrient uptake, biochemical analysis, and soil health impacts to validate its broader agricultural applicability.

Conclusion

In the current experiment, the Seaweed Liquid Fertilizer (SLF) that has been made using the green alga Caulerpa racemosa is tested to determine its effects on the germination and the initial growth of Vigna unguiculata subsp. sesquipedalis (asparagus bean). SLF (1percent, 2percent, 3percent, 4percent, and 5percent) was sprayed on pre-soaked seeds and compared to distilled-water control. The main growth parameters such as the percentage of germination, radicle and hypocotyl length, seedling length, the index of vigor, the index of growth, phytotoxicity, fresh and dry weight, phytomass and productivity, were measured in 15 days. The findings showed that the low to moderate levels of C. racemosa SLF had a significant positive effect on seed germination and seedling vigor. The 2 and 3 percent treatments gave the greatest improvements with 100 percent germination and increased growth between the radicle and seedlings than the control. The 3% SLF treatment had also the highest growth and vigor indices and also showed maximum phytomass and productivity. On the other hand, the lowest germination and growth response was achieved with the 4% concentration and this is an indication of potential inhibitory effect at high doses. The results validate the biostimulant activity of C. racemosa extract and are consistent with previous research on seaweed extracts in the leguminous crops in terms of fertilizer.

References

[1] Abhilash, E.S., Jisby Jacob and Sheeja, P. 2013. Effect of seaweed (Caulerparacemosa) extract on biochemical variations, growth and yield of Vigna mungo. Asia Pacific Journal of Environment Ecology and Sustainable Development. 1:3-5 [2] Abhilash E.S., Shilpha K, Vaishnavi, Akshara, Jishnu, Abinand, Yamuna VG and Binumol M.2025. A Study on the Potential Effects of Seaweed Liquid Fertilizer on the Germination and Growth of Asparagus Bean. IJRASET, 13(10):1315-1319. [3] Anantharaj, M., and Venkatesalu, V. 2001. The Effect of seaweed liquid fertilizer on Vigna catajung, Seaweed Res. Ultiln., 23: 33-39. [4] Bai, N. R., Banu, N. R. L., Prakash, J. W. and Goldi, S. J. 2007. Effects of Asparagopsis taxiformis extract on the growth and yield of Phaseolus aureus. J. Basic Appl. Biol., 1(1) : 6-11. [5] Bokil, K.K., Mehta, V.C., and Datar, D.S. 1974.Seaweed as manure III. Field manural trials on Pennisetum typhoids S.H. (pearl Millets) and Arachis hypogea (Ground nut). Bot. Mar., 15: 148-150. [6] Challen, S.B., and Hemingway, J.C. 1965. Growth of higher plants in response to feeding with seaweed extracts. Proc. 5 Ind. Seaweed Symp 23:85-87. [7] Chitra, G., and Sreeja, P.S. 2013. A Comparative Study on the effect of Seaweed Liquid Fertilizers on the growth and yield of Vigna radiate L. Nat Env and Poll Tech, 12 (2): 359-362. [8] Divya, K., Mary Roja, N., and Padal, S.B. 2015. Effect of seaweed liquid fertilizer of Sargassum wightii on germination, growth and productivity of brinjal. Inter J. of Adv Res in Sci, Engi and Tech, 2(10): 868– 871. [9] Divya, K., Mary Roja, N., and S.B. 2015. Influence of seaweed liquid fertilizer of Ulva lactuca on the seed germination, growth, productivity of Abelmoschus esculentus L. Inter J of Pharma Res, 5(12): 344-346. [10] Erulan, V., Soundarapandian, P., Thirumaran, G., & Ananthan, G. (2009). Studies on the effect of Sargassum wightii extract on the growth and biochemical composition of Cajanus cajan (L.) Millsp. Seaweed Research and Utilization, 31(1–2), 179–185. [11] Rathore, S.S., Chaudhary, D.R., Boricha, G.N., Ghosh, A. 2009. Effect of seaweed extract on the growth, yield and nutrient uptake of soybean under rainfed conditions. South African Journal of Botany 75: 351-355. [12] Sankar, V., Tripathi, P.C., Qureshi, M.A.A., and Lawande, K.E. 2001. Effect of organic seaweed extract on growth, yield and quality of onion (Allium cepa L.) .South Indian Horticulture 49:247-248. [13] Sivasankari, S., Venkatesalu, V., Anantharaj, M., and Chandrasekaran, M. 2006. Effect of seaweed extracts on the growth and biochemical constituents of Vigna sinensis. Bioresource Technology 97: 1745-1751. [14] Thirumaran, G., Anantharaman, P., and Kannan, L. 2007. Effect of seaweed extracts used as a liquid fertilizer in the radish (Raphanu ssativus). Journal of Ecobiology 20(1): 49-52. [15] Verkleij, F.N. 1992. Seaweed extracts in agriculture and horticulture: a review. Biological Agriculture 8: 309-324. [16] Whapham, C.A., Blunden, G., Jenkins, T., and Hankins, S.D. 1993. Significance of betaines in the increased chlorophyll content of plants treated with seaweed extract. Journal of Applied Phycology 5(2): 231-234. [17] Zodape, S.T., Kawarkhe, V.J., Patolia, J.S., and Warade, A.D. 2008. Effect of liquid seaweed fertilizer on yield and quality of okra (Abelmoschus esculentus L.). Journal of Sci. and Industrial Research 67: 111–115.

Copyright

Copyright © 2025 Abhilash ES, Shilpa K, Vaishnavi , Akshara , Jishnu , Abinand , Yamuna VG, Sheeja P Parayil. This is an open access article distributed under the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited.