Mushroom-SRI Farming System
(from SRI Trip Report to China - February, 2004)
Norman Uphoff
A Mushroom-SRI Farming System: We came to Chongzhou to see an interesting application of SRI: its rotation with mushroom production, which is spreading rapidly during the winter season in parts of Sichuan province. It turns out that SRI fits very nicely with mushroom raising, first because the input for growing mushrooms is rice straw, and SRI produces much more of this. Also, the mushrooms need to be grown on soil that has not been chemically fertilized, so this is also a plus for SRI compared to conventional rice production methods. The beds on which mushrooms are grown are made of straw with a layer of dirt spread across them.
Our first visit was to a large area with beds covered by black plastic 'housing' spread over bamboo frames. Farmers who can afford the cost invest about 4,500 RMB per mu, a little over $3,000 per acre, in these temporary structures which maintain higher temperatures in the winter and save labor once constructed. Mushroom growers can earn 10,000 RMB per mu with about 80 days of additional labor, so this is an attractive crop in the winter season, alternating with rice or some other summer crop.
Because it is necessary to avoid buildup of disease, the mushroom beds need to be rotated. So mushrooms are grown in a particular location only every other year. Rice, vegetables or other crops are grown in between. The plastic housing can be easily disassembled and put up in another location for the next winter. The beds are seeded in October or November, after the rice harvest, and are harvested through April, when preparation for a summer crop begins. It takes the straw from about 10 acres of rice to support 1 acre of mushroom production, so straw represents a constraint on the spread of this system. This makes SRI, with as much as 50% more straw, more attractive than just for its production of rice.
We visited also a farm where mushrooms are being grown without the plastic cover. These beds are covered with woven rice straw mats that are easily removed once a day to collect the ripe mushrooms. This method requires much less capital (no plastic or bamboo structure, much less initial labor to set up the operation) but more labor during the season (to take up and replace the mats each day). Mushroom growing is thus accessible to farmers without capital, who can move up the technological ladder with plastic covering once they have made some more money from more labor-intensive operations.
Zheng pointed out that if the beds are appropriately laid out, they can become permanent, with SRI rice planted in two or three rows on the beds in the spring, after mushroom harvesting ends in April. This is an interesting no-till cultivation system. Since the soil is very rich and deep, placing seedlings into the soil of mushroom beds is very easy. The recommended spacing is 40x45 cm, which I thought at first would be too wide for best yield. However, Zheng assured me that mushroom beds are so organically rich and fertile, that this wide spacing works fine. There is no lodging given the strong root systems, and irrigation is not flooding but furrow irrigation, intermittently flooding the channels between the beds. This gives the plants sufficient moisture and greatly reduces water requirements.
The mushroom business is booming in Chongzhou and other parts of Sichuan, with expanding exports to Japanese, European and U.S. markets. We visited a local processing center, operated by a large and now prosperous household, whose new concrete building had 20 rooms, and an agrochemical shop in the front in addition to the processing courtyard in back. Zheng says that he expects SRI to expand very rapidly in this area given its intrinsic benefits plus the positive 'externalities' with mushroom production.
