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The secret behind the "straw spring roll crisp"! Fruit and vegetable residues become regenerated casing soil, and Zhou Zhaoyang grows button mushrooms to practice the circular economy

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The secret behind the "straw spring roll crisp"! Fruit and vegetable residues become regenerated casing soil, and Zhou Zhaoyang grows button mushrooms to practice the circular economy

The "straw spring roll crisp" is a hugely popular photo spot, and its owner is Zhou Zhaoyang of Jinyiyang Mushroom Farm. He not only recycles straw, but also tries fermenting fruit and vegetable residues to make compost, turning it into "regenerated casing soil" to replace the red soil previously used in button mushroom cultivation. In one year, he can deal with more than 3,000 metric tons of fruit and vegetable waste from the Xiluo Fruit and Vegetable Market, and the straw from 400 jia of rice paddies!

"Mr. Sun Yat-sen's revolution failed 10 times before it succeeded; I have failed more than 100 times, enough to chase Edison's record." Zhou Zhaoyang, who this year was honored as a Traceability Expert, shared his own hard-fought experience, hoping more mushroom farmers will join the ranks of the circular economy.

For a single sentence from his son, he began recycling straw to grow button mushrooms

"Dad! The teacher said that with global warming now, if we do not save energy, cut carbon, and protect the environment to save the Earth, the end of the world will come very soon!" his son in elementary school said to him one day. More than ten years ago, Zhou Zhaoyang was still in the transport business, and on the side helped cattle farmers collect corn leaves and corn cobs. On his travels, he found that after the rice harvest, farmers often burned the straw on the spot, seriously affecting driving visibility. Thinking of what his son had said, Zhou Zhaoyang decided to recycle the straw.

Recalling the process of starting his business, Zhou Zhaoyang, born in the 61st year of the Republic of China calendar, has a smile on his face when he speaks, but his words are full of blood and tears. He said that at first he planned to buy up the straw, sort it, and sell it to cattle farmers and mushroom farmers, but the straw was seriously unsalable. "Growing button mushrooms requires large amounts of straw, but Taiwan's button mushroom farmers are very confident, and with any material they are used to handling it themselves and finding it themselves, unwilling to leave it to others." And to solve the unsalable straw, he had the idea of starting a business.

Zhou Zhaoyang, operator of Jinyiyang Mushroom Farm, which practices the circular economy (photo by Lin Yijun)

Zhou Zhaoyang began growing button mushrooms in 2011, and he described it this way: "This is a hard road of no return." At first, the process was quite unsuccessful, and several times the compost fermentation failed, so it could only be dumped directly. He, who once had all black hair, also unknowingly gained a lot of white hair. As the losses grew day by day, he was very anxious and did not know what to do.

Fortunately, Zhou Zhaoyang thought of seeking advice from the Mushroom Research Office of the Agricultural Research Institute, consulting one by one with institute experts such as Shi Xinde, Chen Meixing, Lu Yunsheng, Li Weisong, and the retired Peng Jinteng. The teachers told him everything they knew and gave him much valuable advice. After repeated corrections, Zhou Zhaoyang's mushroom farm finally gradually got on track.

Besides growing button mushrooms, Zhou Zhaoyang also works as a recycler himself, not only recycling straw but also accepting a commission from the Xiluo Fruit and Vegetable Market to recycle fruit and vegetable residues. However, because the fruit and vegetable residues differ in type every day and have high water content, at first he did not know how to use them, and could only make them into compost to give away free to local residents, but acceptance was not high. He suddenly had an idea: could these fruit and vegetable residues be used as raw material for button mushroom cultivation? And with this attempt, there were nearly a hundred failures again.

Button mushroom cultivation casing soil mostly uses red soil, but red soil is being dug up less and less

Taiwan's mushroom industry has records as far back as 1909. Starting in the 1950s, the Taiwan government, in order to promote exports of processed agricultural products, created the three major canning industries of asparagus, pineapple, and button mushrooms. In the past, every rural household grew button mushrooms in winter. As it developed to the present, professional button mushroom farmers have emerged, growing mushrooms in modern environment-controlled mushroom houses with constant temperature and controlled humidity, so cultivation is no longer limited by season and can produce year-round.

The general process of button mushroom cultivation is roughly: making compost, spawning the compost, then putting it on mushroom beds, running the mycelium, and casing soil. Walking into a button mushroom room, you can see the side of the mushroom bed: the bottom layer is straw, and the upper layer is casing soil.

Zhou Zhaoyang said that after button mushrooms are spawned, the mycelium needs 14 days to grow, and only after it has fully covered the compost bed can casing soil be applied. After casing, it takes about 21 days until the first flush of button mushrooms is harvested. From the start of compost making to the complete growth of button mushrooms takes about more than one month. Traditionally, one batch of compost can yield 5-6 cycles of button mushrooms, but to avoid breeding diseases and pests, his farm harvests at most only 3 cycles.

In the process of growing button mushrooms, Zhou Zhaoyang found that the casing soil on top of the button mushrooms was a big problem. He said that traditional button mushroom cultivation uses large amounts of red soil for casing, and after the button mushrooms are harvested, the red soil is discarded. "This red soil is only found in the mountains, and often you even have to line up to buy it." Once, Zhou Zhaoyang failed to buy red soil, and he was startled: "Red soil is being dug up less and less, and one day it will be all dug out. What will we do then?"

Button mushroom compost completed by fermenting fruit and vegetable residues mixed with straw and chicken manure, growing pure white button mushrooms (photo by Lin Yijun)

The Agricultural Research Institute suggested that Zhou Zhaoyang try making regenerated casing soil from button mushroom cultivation remnants

Li Weisong, assistant researcher at the Agricultural Research Institute, said that the function of the upper layer of red soil is to retain water and maintain an environment suitable for button mushroom fruiting. Foreign button mushroom casing soil mostly uses peat soil, because peat soil has the best water retention, but peat soil is expensive, so domestic mushroom farmers mostly replace it with cheaper red soil. However, the red soil after harvest cannot be reused.

Li Weisong explained that used red soil accumulates harmful substances such as salts, along with mycelium that has lost activity, and afterward is prone to breeding pathogenic bacteria. Even if disinfection is carried out, it cannot produce mushrooms because it lacks other beneficial microorganisms. "Red soil that has already grown button mushrooms has different internal conditions, and is no longer an environment suitable for button mushroom growth." To replace red soil, one must think in terms of water retention and suitability for mushroom growth, and the best is a material similar to peat soil.

Plant remnants left from ancient times slowly decompose in swamps, lakes, or waterlogged areas on the ground, and over the years gradually become a layer of fibrous peat soil. Li Weisong said that peat soil is very precious. Even before mining, the places where it is found are only 1 to 2 m thick, and global reserves are limited.

The method the Agricultural Research Institute taught Zhou Zhaoyang imitates the principle of peat soil: first mix fruit and vegetable residues with chicken manure and ferment them into compost. After the compost is successfully made, button mushrooms are grown first. Once button mushroom production is finished, the used residual soil is composted again to become the casing soil for the surface layer of the next batch of button mushrooms. Although it is not like peat soil, which is formed by plants decomposing while soaked in water, because new fruit and vegetable residues are added, along with the straw stalks that were already initially decomposed, the "regenerated casing soil" produced after composting treatment is very similar in concept to peat soil.

Mushroom farm workers are "cleaning the beds," meaning that after harvesting button mushrooms three times, the mushroom beds are cleaned, then sterilized, and straw, spawn, and culture soil are laid down again (photo by Lin Yijun)

The key to complete compost fermentation is crushing; materials are recycled with no waste at all

The fruit and vegetable residues Zhou Zhaoyang uses come from the Xiluo Fruit and Vegetable Market. Before making compost, he must also check the residues for other debris, such as plastic bags and cardboard, all of which must be removed by hand.

After the debris is removed, Zhou Zhaoyang crushes the fruit and vegetable remnants together with straw using a machine, and piles them indoors to ferment for twenty days. During fermentation, after the compost heats up twice, the chemical and microbial reactions reach balance and there is no ammonia odor, which means fermentation is complete. After that, button mushroom spawn is added to the completed compost, and once the mycelium has fully grown, the reused casing medium is spread on top. After button mushroom growth and harvest are finished, the straw compost and casing soil on the mushroom bed are reprocessed and become the next batch of casing soil, recycled with no waste at all.

"At the beginning I paid a lot of tuition." Zhou Zhaoyang explained that making compost takes time and is also quite costly. At first he was not yet familiar with making compost and failed quite a few times. "Compost that has not fully fermented cannot actually be identified by looking or smelling. Only after casing soil is applied and the button mushrooms fail to grow do you know that the making failed."

Li Weisong explained that generally small farms and household vegetable gardens make compost in small amounts, so they are less likely to have the problem of incomplete fermentation. But at Zhou Zhaoyang's scale, not only is the compost volume larger, but fruit and vegetable residues are also added. The key to later achieving stable fermentation was the pre-treatment crushing step.

Li Weisong explained that the types and proportions of fruit and vegetable remnants received every day are different. Crushing before composting increases the contact area after fragmentation and evenly disperses contact among the various raw materials, which can make the overall fermentation speed of the fruit and vegetable residues more consistent. "If in today's residues there is one or half a piece of uncrushed muskmelon or pomelo, it could ruin the entire batch of compost!"

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