Clever use of gypsum powder in edible mushroom production boosts both yield and income

The use of raw gypsum in edible mushroom culture media falls under auxiliary materials. Auxiliary materials are a class of substances used to increase nutrition and improve chemical and physical states, and are used in relatively small amounts. The amount of raw gypsum added to edible mushroom culture media is between 1-3%.

I. The role of adding raw gypsum to edible mushroom culture media in increasing nutrition:

1. Directly supplements the deficiency of sulfur and calcium in the culture medium;

2. Fixes gaseous nitrogen into combined nitrogen, which helps stabilize the ammonia freely present in the compost and reduces nitrogen loss in the culture medium;

3. Can accelerate the decomposition of organic matter in the culture medium, promote the release of soluble phosphorus and potassium in the material, and supply them for absorption and use by the mycelium;

4. Calcium ions can make the colloidal film in the compost disappear, which helps mushroom mycelium absorb nutrients;

5. Raw gypsum can neutralize the oxalic acid produced by mushroom mycelium during growth, and forms a cell membrane containing calcium oxalate on the surface of the mushroom mycelium, which has the effect of defending against external enemies and protecting the mycelium;

6. Increases the cellulose degradation rate of the substrate after fermentation and increases soluble sugars.

II. The main roles of adding raw gypsum to edible mushroom culture media in improving chemical and physical states:

1. Improves the buffering capacity of the culture medium and suppresses the side effect of excessively high pH caused by ammonia gas, which can occur even after spawning;

2. Prevents the culture medium from turning acidic and undergoing anaerobic fermentation, and avoids large changes in the pH of the culture medium;

3. Enhances the coagulation effect of the culture medium on the intercellular substances of certain bacteria, thereby reducing some damage to the culture structure caused by bacterial activity during the composting process;

4. Helps the culture medium reduce its sensitivity to some nutritional supplements added during casing soil application and increases yield;

5. Unlike other heavy metal ions, the calcium provided by raw gypsum is non-toxic and can cause the colloidal particles on the surface of straw to coagulate into large particles and settle out, producing a coagulation phenomenon, forming a physical structure with good aeration, making the culture medium loose, improving water retention and aeration, and promoting the activity of beneficial microorganisms;

6. Raw gypsum also has strong water absorbency and can improve the water-holding capacity of the compost.

III. Scope of application

Calcium sulfate dihydrate (raw gypsum) is a component of culture media and is commonly used in the cultivation substrate for oyster mushrooms, shiitake mushrooms, black wood ear mushrooms, silver ear mushrooms, enoki mushrooms, lion's mane mushrooms, reishi mushrooms, button mushrooms, shaggy ink cap mushrooms, white king oyster mushrooms, king oyster mushrooms, and others.

The chemical composition of calcined gypsum powder is calcium sulfate hemihydrate, which has cementitious properties. After mixing with water, it reverts to calcium sulfate dihydrate. Because of its properties of setting upon contact with water, releasing heat, and reverting, it is rarely used in edible mushroom culture media.