Evaluation of fertilizer potential of seaweed saps on different field crops

• Seaweeds is an integral part of marine coastal ecosystems. They include the macroscopic, multicellular marine algae that commonly inhabit the coastal regions of the world’s oceans where suitable substrata exist. It has been estimated that there are about 9,000 species of macroalgae broadly classified into three main groups based on their pigmentation (for example, Phaeophyta, Rhodophyta, and Chlorophyta; or the brown, red, and green algae, respectively).
• The benefits of seaweeds as sources of organic matter and plant nutrients have led to their use as soil conditioners for centuries. Some 15 million metric tonnes of seaweed products are produced annually, a considerable portion of which is used for nutrient supplements and as biostimulants or biofertilizers to increase plant growth and yield. A number of commercial seaweed extract products are available for use in agriculture and horticulture
• A field study was conducted at ZARS, Mandya, on rice and hybrid maize for evaluating the effect of two sea weed saps viz., Kappaphycus alvarezii -sap (K-sap) and Gracelaria edulis -sap (G- sap) with different concentration through root dipping for rice and sprays.
• The results of the study clearly indicated that application of 15% G sap as root dip along with 15% G sap spray at 25 and 60 days after transplanting were found to be significantly effective in increasing grain yield of rice. Similarly, spraying K or G sap with 10% concentration at 20, 40 and 70 DAS increases grain and stover yield of maize. Among the two seaweed species studied, Gracelaria edulis was found to be superior in obtaining higher yield and nutrient uptake as compared to Kappaphycus alvarezii.