Where is nori generally grown, and how is it fertilized?

Nori is a commonly eaten food ingredient in daily life. In supermarkets it is usually sold in round cake-shaped packages. Bought to make nori egg drop soup, it tastes very fresh and delicious, is rich in nutrients, and is deeply loved by consumers. So where is nori generally grown? What are the fertilization methods?

1. Where is nori generally grown?

The production areas of nori in China are distributed in coastal regions. In Fujian and the coastal areas of southern Zhejiang, Porphyra haitanensis is mostly cultivated, while in the north, Porphyra yezoensis is mainly cultivated. Xiapu County, the “home of nori”, is one of the oldest counties in Fujian and also the earliest area in southern China to cultivate kelp and nori. As early as the Yuan Dynasty, there were records of people in Xiapu cultivating nori, and it holds the national geographical indication for “Xiapu nori”.

In China, the most famous Porphyra yezoensis is Rudong Porphyra yezoensis. In September 2014, Rudong Porphyra yezoensis from Nantong City, Jiangsu Province obtained geographical indication trademark registration.

2. What are the fertilization methods for nori?

1. Spraying method

Prepare fertilizer into 0.5%-1% fertilizer seawater and spray it over the fully floating raft cultivation sea area. In order to reduce loss and improve fertilizer efficiency, spray the fertilizer water onto the nori nets as much as possible and increase the number of sprinklings per day. For semi-floating raft cultivation, after the nets are exposed above the water surface, spray fertilizer water at a concentration of 0.1%-0.2% onto the nets. For spraying time, the effect is better within 1 hour before the tide comes in. After fertilization, if the nets are exposed too long, it is unfavorable to the growth of nori.

2. Soaking method

The soaking method is to prepare fertilizer into about 0.1% fertilizer seawater, place it in a larger container or cabin, soak the nori nets in the fertilizer liquid for about 30 minutes, and then quickly hang the soaked nets on floating rafts. The soaking method has a better effect, but costs too much labor, and is generally carried out in combination with drying the nets.

3. Hanging bag method

That is, fill long plastic film bags with chemical fertilizer and hang them on floating bamboo or directly tie them to the nets, letting them dissolve and diffuse freely. Generally, the fertilizer is changed once per tide. The hanging bag method has a relatively large amount of fertilizer loss and is suitable for large-area cultivation.

3. Key points for nori cultivation

The main pests and enemies during the nori growth period are mainly plant-based ones such as green moss, filamentous green algae, and diatoms, which attach to the nets, occupy seedling positions, compete for nutrients, block light, and mix with the algal body so that it is difficult to distinguish, affecting the quality of the dried product. Animal-based ones include fish of the family Blenniidae, golden pomfret, and Niangai fish, which directly eat the algal body and cause great harm. For removal methods, if plant-based algae attach during the small seedling stage, the nets can be exposed to strong sunlight for twelve hours and then put back into the sea; this kind of miscellaneous algae will turn white and die in the water. Animal enemies are mainly more common in offshore sea areas, and the main removal methods are driving them away, blasting, and hanging medicine bags. There is also bacterial green rot, which, due to factors such as high temperature, overcrowding, and poor water flow, causes the thallus to rot and turn green, and in severe cases the entire sea area rots. Rescue measures: immediately adjust the water layer, dry the nets for more than 20 hours, and then put them back into the sea for cultivation.