Detailed Explanation of Key Techniques for High-Yield Edible Mushroom Cultivation

Currently, the widely cultivated edible mushrooms such as oyster mushrooms, shiitake mushrooms, enoki mushrooms, lion's mane mushrooms, wood ear mushrooms, silver ear mushrooms and button mushrooms can be roughly divided into the mycelium stage and the fruiting body stage, or two growth and development periods. The conditions required by each mushroom during these two stages have similarities as well as differences. This is determined by their biological characteristics. If the favorable conditions they need can be created, high yield and high quality can be achieved.

I. Nutrients, mainly carbon, nitrogen and mineral elements.

1. Carbon nutrients are the main components constituting the mycelium and fruiting bodies, and are also the source of energy required for their growth and development. Carbon substances account for about 50%-65% of the mushroom body composition (dry matter). The cottonseed hulls, sawdust and other culture media used in cultivation are the main source of carbon.

2. Nitrogen nutrients are the main raw materials for proteins and nucleic acids. They are likewise the main components of the mycelium and fruiting bodies, and are also the material basis for the fragrant and delicious taste of edible mushrooms, especially the abundant amino acids (as many as 18 kinds), which cannot be formed without nitrogen.

Carbon and nitrogen nutrients require not only sufficient quantity for the normal development of edible mushrooms, but also a reasonable ratio, commonly known as the carbon-to-nitrogen ratio. For various mushrooms, this ratio is preferably 20:1 during the mycelium growth stage and 30-40:1 during the fruiting body development stage. In production, because the types of culture materials differ, wheat bran, cornmeal, soybean cake powder, ammonium nitrate, urea, etc. are sometimes added to adjust the carbon-to-nitrogen ratio. Applying the same formula to all mushrooms regardless of type, or even arbitrarily changing the materials without following the original formula, with some things missing and others lacking, makes it difficult to achieve high yield and high quality.

3. Mineral elements. The normal growth of edible mushrooms also requires mineral elements and trace elements such as calcium, magnesium, phosphorus, potassium, iron and zinc. Although these substances are needed only in small amounts, they are all important, and generally the content in the main materials can meet the demand. Sometimes substances such as magnesium sulfate, plant ash (potassium) and chicken manure (phosphorus) are also added.

II. Water and Humidity

Water is one of the main components of the mycelium and fruiting bodies, and more importantly, metabolism, the vital activity, cannot proceed without water. Fresh mushroom bodies contain as much as 85%-90% water. The water in the culture medium is the main source of water needed for the growth and development of edible mushrooms, but too much water is instead harmful. The suitable water content is 65%-75%. The standard is that the material has absorbed enough water so that when squeezed by hand, water appears between the fingers but does not drip down. Taking cottonseed hulls as an example, the weight ratio of material to added water is roughly 1:1.2-1.5; adding too much will hinder mycelium growth.

Humidity usually refers to the relative air humidity. This not only has a direct relationship with the growth and development of edible mushrooms, but also affects the release of water within the material. Especially during the fruiting body development period, if humidity is insufficient, yield will certainly be reduced; if it is below 60%, the fruiting bodies will not grow; if below 45%, primordia stop differentiating, and existing primordia may even die. The suitable air humidity is 85%-93% (during the fruiting body growth period). During cultivation, adding water by spraying to raise the relative air humidity is a necessary measure. Especially in the later stage, injecting water into the culture medium or soaking the culture medium can also correspondingly increase yield.

III. Temperature

All mushrooms require certain temperature conditions for normal growth and development. The temperature requirements of the mycelium and fruiting bodies during growth and development differ, and some also prefer alternating temperature conditions; for example, if oyster mushrooms are given a daily temperature difference stimulus of 10°C, it favors the formation and development of fruiting bodies. For the several more commonly cultivated mushrooms listed above, the suitable temperature for mycelial growth is roughly around 25°C (30°C for wood ear mushrooms), and the suitable temperature for fruiting body development is generally around 15°C. Straw mushrooms prefer warmth; mycelia develop better at 35°C, and fruiting bodies develop well at 30-32°C.

Temperature is an important factor affecting the growth and development of edible mushrooms. In production, natural seasonal cultivation is currently mostly used, mainly arranging production according to natural temperature conditions (artificial air conditioning also mainly creates temperature conditions). With advances in science and technology, edible mushroom varieties are now being improved, and changing their temperature characteristics is one of the main goals. For example, for oyster mushrooms and shiitake mushrooms, low-temperature types, medium-temperature types, high-temperature types, and even wide-temperature types with less strict temperature limits have been developed. Therefore, corresponding varieties can be selected according to the temperature conditions of the cultivation period, expanding the cultivation period.

IV. Oxygen and Carbon Dioxide

If oxygen is insufficient, the mycelium of various edible mushrooms will grow poorly, and the fruiting bodies will also grow poorly. Because edible mushrooms themselves also release carbon dioxide during growth and development, the cultivation site must be ventilated.

V. Light

Edible mushrooms do not have strong light requirements; the mycelium can grow under dark conditions. During fruiting body differentiation and growth, a certain amount of scattered light is needed, and direct strong light should be avoided. In complete darkness, fruiting body development is poor and slow. Light can increase their color; without light, the color is pale. Light is also related to temperature. In the north, when using greenhouses to cultivate edible mushrooms, sunlight is needed to raise the temperature, but attention must be paid to preventing excessively high temperatures; when the light is too strong, straw curtains and the like are mostly used for shading.

VI. pH

Edible mushrooms mostly prefer a slightly acidic environment; generally the pH value does not exceed 7 (neutral), and is about 5.5-6.5, but oyster mushrooms are relatively alkali-tolerant and can also grow at pH 8. Lion's mane mushrooms are acid-tolerant and can also grow at pH 5. During cultivation, substances such as sugar that will become acidic are added, and the high-temperature sterilization process will also make the culture medium acidic. Attention should also be paid to the local water quality, that is, its pH value. When mixing materials, attention should be paid to creating a suitable pH environment; sometimes lime or acidic fertilizers such as ammonium nitrate are added, which first increases

calcium and nitrogen, and second can adjust the pH value of the culture material.

To prevent excessive acidity or alkalinity, adding a certain amount of gypsum can have a buffering effect.