IJERD – International Journal of Environmental and Rural Development (2021) 12-1

Research article
erdChanging Spent Mushroom Substrate into a Quality
Vermicompost
SUPAWADEE RUANGJANDA
Department of Soil Science and Environment, Faculty of Agriculture, Khon Kaen University,
Khon Kaen, Thailand

CHULEEMAS BOONTHAI IWAI*
Integrated Land and Water Resource Management Research and Development Center in Northeast
Thailand, Khon Kaen University, Khon Kaen, Thailand
Email: chuleemas1@gmail.com
Received 3 March 2021

Accepted 30 June 2021(*Corresponding Author)

Abstract Safety food and healthy food gain widespread popularity nowadays. In Thailand,
mushroom consumption is increasing because of its high protein content and role as an effective
stimulant of various immune system functions. As mushroom farmers’ respond to this demand,
the need for sustainable waste management of mushroom cultivation has become important.
Therefore, the study examined the growth and reproduction of earthworm and chemical
properties of Eudrilus eugeniae vermicompost cultured under different ratio of spent mushroom
substrate. The study found that application of bedding with spent mushroom substrate at theratio 60:40 gave the highest growth rate of earthworms (2.5%) and had the highest increase innutrient content (Total N, P, K, Mg, Ca) and had the highest decrease in the value of pH,
electrical conductivity, organic carbon and C/N ratio significantly. Based on these results,
application of bedding with spent mushroom substrate at the ratio of 60:40 seemed to be themost suitable for vermicompost production. In general, recycling of spent mushroom substrate
through vermicomposting may reduce the environmental stress and can produce organic
fertilizers with better chemical and biological properties.
Keywords spent mushroom substrate, mushroom, earthworm, vermicompost, vermicompost
quality

INTRODUCTION
Safety food and healthy food gain widespread popularity nowadays. The effect to mushrooms
consumption is increasing because of mushroom are a healthy food. The world production of Pleurotus
ostreatus was about 4.1 million tons in the year 2019 (FAO, 2020). In Thailand has the potential toproduce mushrooms in the industrial sector. The export data of mushroom products in 2011 showedthat the total export volume was 939 tons, increasing from 2008 with 781 tons of export volume. The
total mushroom production is 120,000 tons per year (Chanyuth, 2018).
The production 1 kg of mushrooms generates about 5 kg of spent mushroom substrate(Hrebeckova et al., 2020) .The spent mushroom substrate (SMS) is a by-product generated frommushroom production, which contains a large amount of fungal mycelium and extra-cellular
lignocellulosic enzymes along with various organic substances (carbohydrates, proteins, and fats), as
well as a considerable quantity of inorganic nutrients such as ammonium nitrate, superphosphate, andpotassium salts, (Lou et al., 2017; Gong et al., 2019). In the year 2017 there was about 20.5 million
tons of SMS generated from Pleurotus ostreatus cultivation around the world. (Huan-Na et al., 2017;
Wang et al., 2020). In Thailand found about 1.1 million tons of SMS in the year 2020. These SMS areⒸ ISERD

136

IJERD – International Journal of Environmental and Rural Development (2021) 12-1

commonly sent to landfill or openly burnt at farms and could not be reused in the next cultivation due
to the possibility of contamination which will consequently affect the mushroom production. As
mushroom farmers’ respond to this demand, the need for sustainable waste management of mushroom
cultivation has become important.
Vermicomposting is a sustainable technique to convert organic wastes into a nutrient-rich humuslike product, important substances that are beneficial to plants such as plant growth promoters. throughthe joint action of earthworms and microorganisms under aerobic conditions (Edwards and Burrows,
1988). In addition, it can be easily done with low investment and high benefits. Can do both at thefamily and farm system. Therefore, this method is interesting for reduce SMS or organic waste andleading to produce organic fertilizers.
OBJECTIVE
This research aims to study the growth and reproduction of earthworm and chemical properties ofEudrilus eugeniae vermicompost cultured under different ratio of spent mushroom substrate.
METHODOLOGY
Materials for Vermicomposting
The SMS was obtained from the Sufficiency Mushroom Learning Center, Tha Phra, Mueang, Khon
Kaen, Thailand. Its is waste from the cultivation of Pleurotus ostreatus. The SMS containing sawdust(80-90%), rice bran (5-10%), rice broken (1%), lime (2%), gypsum (0.5%), sodium sulfate (0.2%) andpumice (2%), at 65-70% humidity. All samples are dried in the shade for 7 days to feed earthworms
and bedding was obtained from faculty of Agriculture, Khon Kaen University, Khon Kaen, Thailand
including soil, cow dung, rice husk ash and vegetable waste at ratio 4: 3: 2: 1 dry weight respectively(Iwai et al., 2011).
Treatments and Experimental Design
In this study, the earthworm Eisenia eugeniae (density about 20 pcs/kg) was selected forvermicomposting because it tolerates a wide range of pH, temperature and moisture content. Plastic
buckets of the diameter size 50 cm × height 18 cm were used to accommodate 4 kg of feed materials.
Each container had a 0.2 m2 of exposed surface covered with mosquito net to prevent hindrance fromsmall insects and other microorganisms which could hamper the findings of this study. Punch holes inthe bottom of the tank for good drainage and air. The materials used cultivating earthworms were
cultured under bedding (B) with SMS in 6 different ratios were 100: 0, 80:20, 60:40, 50:50, 40:60 and
20:80 respectively. The study planned a Completely Randomized Design (CRD) there were 6
treatments and 3 replications with 45 days period.
Measurements
The number of earthworms were monitored at the beginning and the end of process following themethods of Gong et al. (2019). The electrical conductivity (EC) and pH were determined in an aqueous
solution (sample: water, 1:10) using a conductivity meter and a pH meter (Unuofin and Mnkeni, 2014).
The wet oxidation method of Walkley (1934) was used for determination of organic carbon (OC).
Total nitrogen was analyzed following a modified semi-micro Kjeldahl method. For the determinationof total phosphorus, potassium, magnesium and calcium 0.2 g of dry sample was digested with 70%(v/v) sulfuric acid and 65% (v/v) hydrogen peroxide. Total phosphorus was measured byⒸ ISERD

137

IJERD – International Journal of Environmental and Rural Development (2021) 12-1

Spectrophotometric molybdovanadophosphate method. Total potassium was determined using a flame
photometer.Total Calcium and Magnesium measured with atomic absorption spectrophotometer.
(AOAC, 2000). C/N ratio values were calculated and analysed.
Statistical Method Analysis
The reported results are the mean of three replicates with standard error (SE). Chemical properties
were analyzed by repeated measures analysis of variance (ANOVA). Mean values were compared by
Tukey's HSD method. Differences were considered significant, only when P values were lower than
0.05.
RESULTS AND DISCUSSION
Earthworm Growth and Reproduction
During the 45 day of vermicomposting, The number of juvenile earthworm significantly increased in
all treatments (p≤ 0.05) and adult earthworm increased in B+SMS 50:50 and B+SMS 60:40 (Table 1).
Table 1 The growth and reproduction of earthworm at the beginning and the end of thevermicomposting process by using Eudrilus eugeniae in different ratio for 45 days
Parameter
B + SMS 100:0

Initial80 ± 0.00

B + SMS 80:20
B + SMS 60:40
B + SMS 50:50
B + SMS 40:60
B + SMS 20:80
F -test80 ± 0.00
80 ± 0.00
80 ± 0.00
80 ± 0.00
80 ± 0.00
ns

The number of adult earthworm
Final
Percent change (%)
77 ± 1.11-3.75 ± 1.38
77 ± 2.00
82 ± 0.89
83 ± 1.56
76 ± 4.22
80 ± 0.00
ns-3.75 ± 0.63
2.50 ± 1.11
3.75 ± 0.63
-5.00 ± 1.88
0.00 ± 0.00
ns

Juvenile
earthworm
4 ± 1.56b
49 ± 11.78ab
101 ± 7.00a
49 ± 14.00ab
69 ± 11.78ab
62 ± 2.44ab*

ns = non significantly different *, ** = significantly different at p≤ 0.05 and p≤ 0.01, respectively. Similar letter within thesame column indicates no significant difference by Tukey's HSD test. The numerical value of ± shows standard error. B =Bedding (soil: cow dung : rice husk ash: vegetable waste; 4:3:2:1 ), SMS = spent mushroom substrate.

These changes in amount of earthworm may have reflected the greater availability of food at thestart of the incubation and the reduction of food over time. The substrate ratios added significantly
altered Eisenia eugeniae number during the vermicomposting. The maximum individual number ofearthworm and maximum individual growth rate significantly higher in all bedding with SMS addition
treatments than in the control. Among all substrates tested, the growth rate of earthworm had thehighest increase in the B+SMS 60:40 and B+SMS 50:50. However, low quality organic waste may
cause earthworms to lose weight and increase mortality during vermicomposting. (Gong et al., 2019).
Physiochemical Change during Vermicomposting Process
The pH, EC, organic carbon and C/N ratio value at the end of the process significantly decreased in alltreatments (p≤ 0.05). (Table 2) The decreasing of pH in the early stage can be attributed to thedegradation of the organic compounds, which leads to the generation of ammonia, and the subsequent
decrease in pH might be due to the production of intermediate organic acids (Hanc and Chadimova,2014). The B+SMS 60:40 treatment had the highest decrease in the value of EC was 1.67 dS m -1
Ⓒ ISERD

138

IJERD – International Journal of Environmental and Rural Development (2021) 12-1

(43.85%). The decreasing of EC during vermicomposting confirms by Lou et al. (2017) which spentmushroom compost for 12 weeks using earthworms Eisenia andrei and Eisenia fetida. It had (8580 μS
cm-1) decreased about 40% when compared to week zero (14,650 μS cm-1).
Table 2 Chemical characterization of materials at the beginning and at the end of thevermicomposting process using Eisenia eugeniae
B + SMS
100:0

ParameterpH

B + SMS
80:20

B + SMS
60:40

B + SMS
50:50

B + SMS
40:60

B + SMS
20:80

Ftest

Initial7.69 ± 0.11b

8.06 ± 0.07a

7.80 ± 0.08ab

7.53 ± 0.10bc

7.51 ± 0.01bc

7.36 ± 0.05c

**

Final

7.64 ± 0.02a

7.56 ± 0.03ab

7.35 ± 0.06ab

7.30 ± 0.18ab

7.30 ± 0.04ab

7.24 ± 0.11b*(%)- 0.65 ± 1.22b- 6.20 ± 0.79a- 5.77 ± 0.56a-3.05 ± 1.20ab-2.80 ± 0.70ab-1.63 ± 1.00b**

Initial2.55 ± 0.05b

2.48 ± 0.11b

2.96 ± 0.16ab

2.57 ± 0.11b

3.14 ± 0.17a

3.09 ± 0.13a

**

Final

2.27 ± 0.15ab

1.97 ± 0.13ab

1.67 ± 0.09b

1.57 ± 0.23b

1.83 ± 0.08b

2.84 ± 0.52a**

Change(%)-11.03 ± 1.13c-20.30±3.54bc-43.85± 3.93a-39.17±6.36ab-41.59± 3.43a-23.69±1.13bc**

Organic carbon(%)

Initial3.41 ± 0.19d

5.12 ± 0.04d

11.74 ± 1.24b

8.46 ± 0.64c

17.28 ± 0.18a

18.27 ± 1.29a

**

Final

2.69 ± 0.33d

3.49 ± 0.27d

4.62 ± 0.16c

5.85 ± 0.16b6.95 ± 0.22b

18.16 ± 0.52a**

Change(%)-20.63 ± 3.71b-31.76 ± 5.75b-60.14 ± 3.07a-30.31 ± 6.25b-59.77 ± 1.37a- 0.24 ± 4.76c**

Total nitrogen(g kg-1)

Initial1.17 ±0.02

1.28 ± 0.02

1.17 ±0.02

1.40 ±0.00

1.52 ±0.02

1.41 ±0.02

nsChange-1

EC (dS m )Final

1.87 ± 0.02b2.45 ± 0.02ab

3.03 ± 0.02a

2.10 ± 0.02b

2.33 ± 0.02ab

1.75 ± 0.00b

**

(%)

61.11 ± 7.41ab

97.22±12.50ab

166.67 ± 2.38a

50.00± 12.50b

55.00±13.33b

**

Total
phosphorus(g kg-1)

Initial0.36 ± 0.00a

0.34 ± 0.00ab

0.30 ± 0.00c

0.30 ± 0.00c

0.32 ± 0.00bc

30.56 ±
12.50c0.25 ± 0.00d

Final

0.79 ± 0.00a

0.64 ± 0.00b0.64 ± 0.00b

0.69 ± 0.00b

0.65 ± 0.00b

0.54 ± 0.00c**

Change(%)

119.63±5.63ab

83.56 ± 3.74c

113.63±3.05ab124.85±6.79a

100.09±7.78bc

113.09±3.12ab**

Total potassium(g kg-1)

Initial2.19 ± 0.01ab

2.10 ± 0.01ab

1.83 ± 0.01b

2.05 ± 0.01ab

2.28 ± 0.01a

2.02 ± 0.01ab

ns

Final

2.68 ± 0.01

2.97 ± 0.02

2.69 ± 0.02

2.46 ± 0.01

2.89 ± 0.01

2.44 ± 0.01

ns

Change(%)

22.81 ± 8.81

42.11 ±12.74

48.70 ± 12.58

20.35 ± 2.74

27.10 ± 3.04

20.78 ± 0.57

ns

Magnesium(g kg-1)

Initial1.02 ± 0.00d

1.35± 0.01cd

1.52 ± 0.01cd

1.65 ± 0.02bc

2.18 ± 0.02b

3.26 ± 0.02a

**

Final

1.21 ± 0.01d

1.49 ± 0.00cd

1.67 ± 0.02cd

1.97 ± 0.02c

2.52 ± 0.01b3.68 ± 0.02a**

Change(%)

18.96 ±0.15

11.07 ±2.26

10.26 ±3.85

21.07 ±1.79

16.54 ±5.74

13.84 ±1.03ns

Calcium(g kg-1)

Initial0.80 ± 0.01d

1.00 ± 0.00cd

1.06 ± 0.01cd

1.28 ± 0.00c

1.79 ± 0.01b2.80 ± 0.02a

**

Final

0.88 ± 0.01d

1.09 ± 0.00cd

1.41±0.01bcd

1.53 ± 0.01bc

1.91 ± 0.01b

3.96 ± 0.02a**

Change(%)

9.51 ± 4.69c

9.30 ± 3.13c

34.23 ± 4.38ab

19.40 ± 3.55b7.05 ± 3.05c

42.40 ± 3.36a*

C/N ratio

Initial29.92 ± 4.75c

40.61 ± 5.23c

102.45±5.04ab

60.45 ± 4.59bc

115.04 ± 9.83a

135.68 ± 9.07a**

ChangeChange**Final

14.63 ± 2.41c

14.32 ± 0.76c

15.46 ± 1.95c

28.49 ± 4.19b

30.02 ± 3.11b

103.77 ± 2.94a

**

(%)

-50.01 ± 5.83b-63.86±5.95ab-84.50 ± 2.96a-52.60 ± 8.07b-73.80±2.54ab- 20.00 ±
6.47c

**

ns = non significantly different *, ** = significantly different at p ≤ 0.05 and p≤ 0.01, respectively. Similar letter within thesame column indicates no significant difference by Tukey's HSD test. The numerical value of ± shows standard error. B =Bedding (soil: cow dung : rice husk ash: vegetable waste; 4:3:2:1 ), SMS = spent mushroom substrate. (-) = The percent
change of nutrient decreased.

The SMS is comprised of easily degradable carbon substrates which tend to benefit the microbial
growth, resulting in a greater organic matter decomposition rate. From the result, had the highest
decrease in the percent change of organic carbon (60.14%) and C/N ratio (84.50%) at the ratio 60: 40
of bedding with SMS. The organic carbon loss is likely due to the mineralization of the organic matterⒸ ISERD

139

IJERD – International Journal of Environmental and Rural Development (2021) 12-1

through time (Gong et al., 2019). Elvira et al. (1998) reported that during composting there was a lossof 20-43% of organic carbon in the form of carbon dioxide. Due to microbial respiration and from theingestion of organic matter. The longer duration either for vermicomposting or composting indirectly
enhanced the quality of final end product as a result of the loss of carbon and increased nitrogencontent (Kaviraj and Sharma, 2003).
The nitrogen, phosphorus, magnesium and calcium content at the end of the process significantly
increased in all treatments (p≤ 0.05). (Table 2) While, the percent change of potassium had the highest
increased at the ratio 60:40 of bedding with SMS (48.70%). But The potassium content non
significantly increased at the end of the process due to microorganisms present in vermicompost utilize
bound nutrients in vermicompost for their survival. This results in increased microbial activity, whichleads to quicker immobilization of nutrients, causing decreases potassium content in vermicomposting.
The percent change of nitrogen had the highest increased at the ratio 60:40 of bedding with SMS(166.67%) due to the high growth rate of earthworm. Causing bacteria to play a role in themineralization process. Moreover, the excretion of mucus, fluids, enzymes and dead tissue during
digestion processes containing nitrogen effect the total nitrogen content increased (Suthar, 2007; Lou etal., 2017). Application of bedding with SMS at the ratio 50:50 gave the highest percent change ofphosphorus (124.85%) and magnesium (21.07%) because of earthworm like a media to increased
phosphatase enzyme content, which increased content by waste from the gut becomes earthworm effectto increased phosphorus content in vermicompost (Gong et al., 2019). The calcium content had thehighest increase in vermicompost from bedding and SMS at the ratio 20:80 was 3.96 g kg-1. Increasing
SMS rate will be higher of calcium content. This is because in the process of mushroom production areadded lime, gypsum, salt and pumite to be used as food and adjusted the acidity and alkalinity for goodmushroom growth. This results cause a large amount of calcium in waste from mushroom cultivation.
CONCLUSION
Waste from mushroom cultivation could improve vermicompost quality. It is a biological method that
relies on earthworms farming to convert organic matter into high quality organic fertilizer. It was foundthat the spent mushroom substrate contained high protein and carbon content as a food source forearthworms. It can increase the amount of nutrients and microorganisms that are beneficial to plants.
Application of bedding with spent mushroom substrate at the ratio of 60:40 seemed to be the mostsuitable for vermicompost production in term of plant nutrition and earthworm production. In general,
recycling of spent mushroom substrate through vermicomposting may reduce the environmental stressand can produce organic fertilizers with better chemical and biological properties.
ACKNOWLEDGEMENTS
We would like to acknowledge the scholarship from Research Fund for Supporting Lecturer to Admit
High Potential Student to Study and Research on His Expert Program Year 2019, Integrated Land andWater Resource Management Research and Development Center in Northeast Thailand and JapaneseChamber of Commerce, Bangkok Scholarship 2019 and Department of Soil Science and Environment,
Faculty of Agriculture, Khon Kaen university, Khon Kaen, Thailand for facility supported thisresearch.
REFERENCES
Edwards, C.A. and Burrows, I. 1988. The potential of earthworms composts as plant growth media. 211-219. In
Edwards, C.A. and Newrhouser, E.F. (Eds.), Earthworms in Waste and Environmental Management, SPB
Academic Publishing, The Hague.
Ⓒ ISERD

140

IJERD – International Journal of Environmental and Rural Development (2021) 12-1

Elvira, C., Sampedro, L., Benftez, E. and Nogales, R. 1998. Vermicomposting of sludges from paper mill anddairy industries with Eisena andrei: A pilot-scale study. Bioresource Technology, 63, 205-211.
Gong, X., Li, S., Carson, M.A., Chang, S.X., Wu, Q., Wang, L., An, Z. and Sun, X. 2019. Spent mushroom
substrate and cattle manure amendments enhance the transformation of garden waste into vermicomposts
using the earthworm Eisenia fetida. Environmental Management, 248, 1-12.
Hřebečková, T., Wiesnerová, L. and Hanč, A. 2020. Change in agrochemical and biochemical parameters during
the laboratory vermicomposting of spent mushroom substrate after cultivation of Pleurotus ostreatus.
Science of the Total Environment, 739.
Huan-Na, L., Yu Tao, W. and Ming-Jun, Z. 2017. Evaluation of spent mushroom compost as a lignocellulosic
substrate for hydrogen production by Clostridium thermocellum. International Journal of Hydrogen Energy,
42, 26687-26694.
Iwai, C.B., Ta-oun, M., Seripong, S. and Champar-ngam, N. 2011. Vermicomposting: Good management
practice for waste, soil and yield safety. Department of Plant Sciences and Agricultural Resources, Land
Resources and Environment Section, Faculty of Agriculture, Khon Kean University, Thailand, 171.
Kaviraj and Sharma, S. 2003. Municipal solid waste management through vermicomposting employing exotic
and local species of earthworms. Bioresource Technology, 90, 169-173.
Lou, Z., Sun, Y., Zhou, X., Baig, S.A., Hu, B. and Xu, X. 2017. Composition variability of spent mushroom
substrates during continuous cultivation, composting process and their effects on mineral nitrogentransformation in soil. Geoderma, 307, 30-37.
Ndegwa, P.M. and Thompson, S.A. 2000. Effects of C-to-N ratio on vermicomposting of biosolids. Bioresource
Technology, 75, 7-12.
Suthar, S. 2007. Nutrient changes and biodynamics of epigenic earthworm Perionyx excavatus (Perrier) during
recycling of some agriculture waste. Bioresource Technology, 98 (8), 1608-1614.

Ⓒ ISERD

141