Fermented sargassum or huiro: Preparation, properties and uses
Macrocystis pyrifera (Linnaeus) C.Agardh, commonly called sargassum or huiro (Figure 1) belongs to the Laminariaceae family, known as brown algae. Today we are going to show you how to prepare a fermented sargassum or huiro, its properties and use as a fertilizer.
In Chile it is distributed from Tocopilla to Tierra del Fuego, forming extensive underwater forests, on rocky substrate up to 30 meters deep on the coastal edge. This seaweed is used in the food industry as a thickener, emulsion stabilizer, as a mouthfeel (taste) and palatability improver.
Figure 1. Seaweed collected along the Puerto Natales coastline.
In the agricultural sector, algae are an important active ingredient in products marketed as biostimulants or bioprotectors, due to their phytohormone content, their abundance and constant accessibility throughout the year for cultivation. Important growth-promoting substances have been identified, such as cytokinins, auxins, abscisic acid, gibberellins, salicylic acid, polyamines, and ethylene.
Biostimulants are substances that, applied to plants, seeds or the soil, promote plant growth, the use of nutrients, improve tolerance to stress caused by frost or thermal variations and improve the quality of the harvest (Espinosa et al., 2022). ; EL Boukhari et al., 2022).
Sargassum fermentation: algae in rural agriculture
There is a very marked integration between agricultural activities and the use of the bordemar in the peasant rural system. The marine algae that the sea throws onto the beach are collected and used as biofertilizers together with the farmyard fertilizer; as frost and blight control.
This practice is widely used in sectors far from urban centers, mainly in the Los Lagos region and other coastal areas of the country (Sipam Chiloé). Although algae do not contain significant amounts of macro and microelements, it does have traces of all of them.
In addition, thanks to their high fiber content, they act as soil conditioners and contribute to moisture retention, and the presence of plant phytohormones help improve seed germination and provide greater crop resistance to frost and poor conditions. stress, as well as stimulates early flowering and delayed senescence.
The objective of this publication is to provide background information on the preparation, properties and recommendations for the use of a fermented preparation of sargassum (Macrocystis pyrifera) as an agroecological practice to be implemented in coastal areas of the Magallanes region.
Ingredients to prepare a fermented sargassum or flee
– 3 buckets (20 liters) of sargassum or brown seaweed (chopped with a hoe to promote decomposition).
– 3 loaves of diluted chancaca.
– 2 liters of whole milk 80 liters of water (if drinking water is used, try to let it rest for at least 12 hours to volatilize the chlorine).
Figure 2. Drum preparation. The liquid materials and the chopped algae are arranged.
Preparation of the fermented sargassum
Arrange the ingredients in a 100-liter drum (Figure 2), stir at least twice a day, to promote aerobic activation. If possible, it is recommended to incorporate an aerator to oxygenate the preparation. This process lasts from 30 to 45 days.
Once the elaboration time has passed, the concentrate is filtered and harvested, separating the liquids from the remains of algae. It is recommended to pack them in 20-liter drums without lids, placing them in a cool, dark place (Figure 6), or use them immediately at the beginning of the season, since the finished product cannot be stored for more than one month.
The nutritional content values of the fermented sargassum are presented below, according to evaluations carried out by INIA. The results are referential and may vary depending on the time of year and area where the algae are collected.
Results and properties of algae fermentation
According to the results obtained from the sample, it presents a high concentration of Potassium (K) and Calcium (Ca), which could indicate that this bio-input would contribute especially to fruit crops, such as strawberries, sarsaparilla or tomato, enhancing the flavor, color and postharvest life, in addition to having a protective effect against environmental stress.
This fermentation can also be used in the same dilution for imbibition or soaking of seeds, immersion of pre-transplant seedlings or post-sowing irrigation.
The recommendation for use is in a 10% dilution (with this it is possible to reduce the conductivity), applying via irrigation twice a week. It is worth mentioning that the use of this bio-input does not replace a fertilization plan, being considered a complementary practice to other techniques derived from agroecology.
Table 1. Chemical analysis of sargassum fermentation.
