TECHNOLOGY FOCUS - INORGANIC CHEMISTRY - Preferred Method: The method comprises breeding sea tangle in a semi-closed fence-shaped breeding raft or closed fence-shaped breeding raft. The method comprises applying iodine fertilizer using a line bundle containing iodine fertilizer bag. The method comprises (a) uniformly mixing (in wt.%) iodine-containing material (0.1-36), phosphorus-containing material (0.1-2), nitrogen-containing substance (0.1-40), carbon-containing material (0.1-40) and sodium chloride (balance) to obtain iodine fertilizer, and placing in a cool and dry place; (b) adding iodine fertilizer into a fertilizer bag, adding small stone blocks, discharging air from the bag, squeezing the bag opening, rotating the fertilizer bag for 1-3 cycles, folding with a rope of 60-80 cm, winding in the bag opening containing the fertilizer for two turns, tying a knot to tightly enclose, folding the bag opening downwards, winding the bag opening using rope for 2-3 turns, and tightly tying the knot; and (c) connecting the sea tangle rope with the sea tangle breeding farm, each rope is tied with one fertilizer bag, making two small holes on the fertilizer bag using a toothpick, completely submerging the fertilizer bag in sea water, where the distance of upper end of the fertilizer bag from the sea water surface is 2-20 cm, and replacing fertilizer bag for each 30 days, where the fertilizer applying time is from sea tangle seedling breeding to sea tangle harvesting. The fertilizer applying time is between 40 days after the sea tangle seedling breeding for and 20 days before the sea-tangle harvesting. Preferred Components: The iodine-containing material comprises potassium iodide and potassium iodate (preferred), sodium iodide, sodium iodate, sodium periodate, hydroiodic acid, iodine, hydrogen iodide, carbon tetraiodide, nitrogen triiodide, silver iodide, 5-iodo-2-pyridinamine, sea algae iodine, seaweed iodine, iodized salt, iodide, iodate, hydroiodide, iodine containing organisms, iodine containing soil and iodine containing solution. The phosphorus-containing substance comprises diammonium hydrogen phosphate (preferred), ammonium dihydrogen phosphate, phosphorus pentoxide, superphosphate, fused calcium-magnesium phosphate, triple superphosphate, tricalcium phosphate, bird excrement, animal bone powder and fish bone powder. The nitrogen containing substance comprises ammonium bicarbonate (preferred), ammonium carbonate, ammonium nitrate, sodium nitrate, potassium nitrate, ammonium sulfate, ammonium hydrogen sulfate, urea, aqueous ammonia, ammonium chloride, ammonium dihydrogen phosphate and diammonium hydrogen phosphate. The carbon-containing substance comprises ammonium bicarbonate (preferred), ammonium carbonate, sodium carbonate, sodium bicarbonate, calcium carbonate, calcium bicarbonate, magnesium carbonate, carbonic acid, formic acid, acetic acid, methanol, ethanol, formaldehyde, acetaldehyde and acetone. The iodine fertilizer comprises potassium iodide (0.1-25, preferably 12), diammonium hydrogen phosphate (0.1-1.5, preferably 1), ammonium bicarbonate (0.1-39, preferably 33) and sodium chloride (balance).    TECHNOLOGY FOCUS - INSTRUMENTATION AND TESTING - Preferred Components: The height of the breeding raft is not greater than 10 cm. The fertilizer bag is a plastic self-seal bag.