Formulation trial for cultivating Agrocybe aegerita (tea tree mushroom) with mulberry sawdust

At present, Fujian, Jiangxi and other places mostly use hardwood sawdust and cottonseed hulls to cultivate Agrocybe aegerita, but the yield is relatively low. This trial aims to explore suitable formulations for cultivating Agrocybe aegerita with mulberry sawdust and silkworm excrement, in order to make full use of local resources, save costs and improve economic returns.

1 Materials and methods

1.1 Test strain Agrocybe aegerita No. 1, provided by the Kexing Edible Fungi Research Institute of Gutian, Fujian.

1.2 Test formulations (1) cottonseed hull 82%, wheat bran 18%; (2) cottonseed hull 36%, mulberry sawdust 36%, rice straw powder 10%, silkworm excrement 9%, wheat bran 9%; (3) cottonseed hull 18%, mulberry sawdust 54%, rice straw powder 10%, silkworm excrement 9%, wheat bran 9%; (4) mulberry sawdust 72%, rice straw powder 10%, wheat bran 18%; (5) mulberry sawdust 72%, rice straw powder 10%, wheat bran 9%, silkworm excrement 9%. To the above formulations were additionally added corn flour 5%, gypsum 2% and lime powder 3%.

1.3 Test method Weigh the substrate according to the formulation. First, thoroughly wet the cottonseed hull, mulberry sawdust and rice straw powder with 2% lime powder in water, mix evenly and pile up. When the pile temperature reaches about 60°C, maintain for 24 h, turn the pile, and continue fermentation for 2 d. When the fermented material is covered with white actinomycetes and has a fragrant smell, then mix in the wheat bran, silkworm excrement (soaked in water for 20 min first and then air-dried), corn flour and gypsum, and adjust the pH to 9-10 with 1% lime water, with a water content of 60%. Fill into bags, sterilize and inoculate (17 cm x 33 cm x 0.045 cm high-pressure polyethylene gusseted bags, filling height 16 cm). After inoculation, place in a 20-26°C culture room for dark culture. During the mycelial growth period, sample 10 bags every 5 days to measure mycelial growth. When the mycelium reaches the bottom of the bag, move into the cultivation room. Each treatment of 50 bags is one plot, with 3 replicates, in a randomized block design; extra bags serve as guard rows and their yield is not counted. The mushroom house temperature is controlled at 10-26°C, with a certain amount of scattered light maintained, spraying water on the floor and into the air 3-4 times daily, and the relative air humidity kept at 85%-95%. Harvest and weigh when the cap is in a hemispherical shape. After the first flush, clean the surface of the substrate, rest the mycelium for 7-12 d, and then produce the next flush. After each flush, replenish water at 50-100 mL/bag, for a total of 3 flushes.

2 Results and analysis

2.1 Mycelial growth of each formulation As seen in Table 1, formulations (4) and (5) showed fast mycelial growth; formulations (2) and (3) grew more slowly; formulation (1) was the slowest, requiring 46 d.

Table 1 Mycelial growth rate of each formulation

Formulation (1) (2) (3) (4) (5)

Mycelial growth rate (mm/d) 3.5 4.6 4.9 5.1 5.0

Days to full bag (d) 46 38 33 31 32

Mycelial vigor + + + + +

2.2 Yield of each formulation The test results showed that the yield of formulation (1) differed little among flushes, while the yield of formulations (3) and (4) was concentrated in the first flush, and lowest in the third flush. The yield of formulation (2) was even higher than that of formulation (1). This may be because formulations containing more cottonseed hull have slower degradation of cottonseed hull, so the yield of each flush is more balanced. From the analysis of biological efficiency, formulation (2) was the highest. This is because the nutrient degradation rate and air permeability of formulation (2) were both better than those of the other 4 formulations. Formulations (4) and (5) were similar in growth rate and yield, indicating that the nutritional effect of silkworm excrement and wheat bran is similar.

Table 2 Yield and biological efficiency of each formulation (units: kg, %)

Formulation (1) (2) (3) (4) (5)

Total yield 12.92 14.07 10.42 9.10 9.04

Biological efficiency 64.6 70.3 52.2 45.5 45.2

First flush share 33 40 51 64.5 63.4

2.3 Economic benefit analysis Calculated according to local market prices in 2005, from Table 3, formulation (5) had the highest output-to-input ratio, followed by formulations (2), (3) and (4); formulation (1) had the smallest output-to-input ratio at 6.45:1, but formulation (2) had the highest economic benefit.

Table 3 Cost accounting of each formulation (yuan)

Formulation (1) (2) (3) (4) (5)

Cottonseed hull 14.76 6.48 3.24 - 0

Mulberry sawdust - 1.44 2.16 2.88 2.88

Rice straw powder - 0.20 0.20 0.20 0.20

Wheat bran 3.6 1.8 1.8 3.6 1.8

Silkworm excrement - 0.9 0.9 0 0.9

Other 1.62 1.62 1.62 1.62 1.62

Total 19.98 13.44 9.92 8.30 7.40

Output 129.2 140.7 104.4 91.0 90.4

Output-to-input ratio 6.45:1 10.43:1 10.4:1 10.9:1 12.2:1

Note: (1) cottonseed hull 0.90, mulberry sawdust 0.20, rice straw powder 0.10, wheat bran 1.00, silkworm excrement 0.05, corn flour 1.2, gypsum 0.6, lime powder 0.3 yuan/kg; (2) dry material 0.4 kg/bag, 50 bags/treatment, totaling 20 kg dry material/treatment; (3) fresh Agrocybe aegerita 10 yuan/kg.

3 Summary and discussion

3.1 The test results show that with cottonseed hull and mulberry sawdust each accounting for 36%, formulation (2) is the most ideal, with the highest biological efficiency, the highest economic benefit, relatively balanced fruiting, and a relatively high output-to-input ratio. Next is formulation (3), which is mainly mulberry sawdust with a small amount of cottonseed hull appropriately added, and is also worth using.

3.2 With the rapid development of the edible fungi industry and the further deepening of the national forest protection policy, using large amounts of silkworm and mulberry by-products to produce edible fungi is indeed a new way to solve the shortage of raw materials for edible fungi production, and has good development prospects.