Thakur, R.Singh, Sudhir Kumar2017-06-162017-06-162015http://krishikosh.egranth.ac.in/handle/1/5810020950EFFICACY OF SEAWEED SAP ON PRODUCTIVITY AND QUALITY OF RICERice is a major cereal food crop to feed the ever increasing population of the country. Excessive application of inorganic fertilizer degrade the soil health and environment. Under this situation, application of seaweed sap may play a great role to substitute the commercial fertilizer. Keeping these facts in view, an experiment on “Efficacy of seaweed sap on productivity and quality of rice” was conducted at Birsa Agriculture University, Ranchi (23º17‟ N latitude, 85º19‟ E longitude and 625 m above msl altitude) during rainy season of 2012 and 2013 on sandy loam soil with pH 5.7 having medium in organic carbon (0.45%), available phosphorus (13.96 kg/ha), potassium (169.41 kg/ha) and low in available nitrogen (255.88 kg/ha). Treatment consisted of 2-fertilizer levels viz., 100 and 50 % recommended fertilizer in main plot, 2-sap source viz., Kappaphycus alvarezii and Gracilaria edulis in sub plot and 6-sap concentration viz., 0 (water), 2.5, 5.0, 7.5, 10.0 and 15% in sub-sub plot laid out in split plot design and replicated thrice. Results showed that Rice fertilized with 100% recommended fertilizer (120, 26.2 and 33.2 kg N, P and K/ha) produces taller plant (97.5 cm), higher leaf area index (3.85), dry matter (982.1 g/m2), crop growth rate (5.74 g/m2/day), relative growth rate (2.79 g/g/day), productive tillers (252/m2), grains/panicle (65.0), panicle length (21.2 cm) resulting in higher grain (3116 kg/ha) and straw (4234 kg/ha) yield, protein content (8.1%), protein yield (254.2 kg/ha), nitrogen uptake (80.9 kg/ha), phosphorus uptake (18.5 kg/ha), potassium uptake (65.7 kg/ha), sulphur uptake (11.0 kg/ha), net return (` 22473/ha), benefit: cost ratio (0.89) with maintaining maximum organic carbon (0.45%), available nitrogen (249.7 kg/ha), phosphorus (14.4 kg/ha) and potassium (160 kg/ha) content of the soil as compared to 50% recommended fertilizer. Crop sprayed with Kappaphycus alvarezii produces taller plant (96.4 cm), higher leaf area index (3.78), dry matter (978.5 g/m2), crop growth rate (5.66 g/m2/day), net assimilation rate (3.50 g/m2/day), grains/panicle (66.0), panicle length (20.8 cm) resulting in higher grain (3031 kg/ha) and straw (4151 kg/ha) yield, protein yield (238.7 kg/ha) and carbohydrate content (68.2%) than Gracilaria edulis. Spraying of 10% sap concentration produces significantly taller plant (99.4 cm), higher leaf area index (3.85), dry matter (1016.9 g/m2), crop growth rate (6.05 g/m2/day), relative growth rate (2.83 g/g/day), productive tillers (269.0/m2), 1000-grain weight (24.0 g), panicle length (21.9 cm) resulting in higher grain (3525 kg/ha) and straw (4633 kg/ha) yield, protein yield (277.8 kg/ha) and carbohydrate content (68.5%) as compared to lower concentration. Crop sprayed with Kappaphycus alvarezii led to higher nitrogen uptake (77.2 kg/ha), phosphorus uptake (17.0 kg/ha), sulphur uptake (10.4 kg/ha) with maintaining maximum organic carbon (0.43%), available nitrogen (244.2 kg/ha), phosphorus (14.1 kg/ha) and potassium (154.2 kg/ha) of the soil than Gracilaria edulis. Application of 10% sap concentration of Kappaphycus alvarezii or Gracilaria edulis gave highest nitrogen (85.1 kg/ha), phosphorus (19.3 kg/ha), potassium (72.0 kg/ha) and sulphur uptake (12.1 kg/ha) as compared to lower concentration. Application of Kappaphycus alvarezii gave higher net return (` 22791/ha), benefit: cost ratio (0.96) than Gracilaria edulis. Among different concentration level of seaweed sap, spraying of 10% sap concentration of Kappaphycus alvarezii or Gracilaria edulis produces significantly higher net return (` 28590/ha), benefit: cost ratio (1.17) as compared to lower concentration. Rice receiving 100% recommended fertilizer and sprayed with 10% Kappaphycus alvarezii is productive and remunerative it gives higher crop growth rate (7.33 g/m2/day), productive tillers (288.0), grain yield (4216 kg/ha), straw yield (5376 kg/ha), net return (` 37094/ha) and benefit: cost ratio (1.42) than rest of the combinations of fertilizer, sap and its concentration. Further, crop with 50% recommended fertilizer and sprayed 2.5% concentration of either Kappaphycus alvarezii or Gracilaria edulis is as high productive and remunerative as that of 100% recommended fertilizer alone. Hence, application of 2.5% either Kappaphycus alvarezii or Gracilaria edulis can curtail the 50% fertilizer requirement of the crop.en-USnullThesis