Aquaculture Research. 2021;00:1–8. wileyonlinelibrary.com/journal/are | 1 © 2021 John Wiley & Sons Ltd 1 | INTRODUCTION Mushrooms, the edible fungi, contain some healthy compounds, such as polysaccharide and triterpenes, and low calorie. Therefore, the demand for mushrooms is gradually increased. The annual turn- over of mushroom is around NT$ 13.3 billion, which is counted around 18% of the total vegetable production value (NT$ 73.3 billion) in Taiwan (Council of Agriculture, Executive Yuan R.O.C., 2015). Currently, mushrooms are typically cultivated within a 3-D architectural structure inside air-conditioned facilities. Substrates used commonly in mushroom production include agricultural by- products, such as cereal straw, rice, wheat, corn, and barley, cotton, cobs, husks, and pulp (Chang & Miles, 1989). After mushrooms are harvested, the spent mushroom substrate (SMS) becomes an agri- cultural wastes and by-products, which were estimated about 0.25 million tons per year in Taiwan. SMS has now be applied as compost, Received: 16 November 2020 | Revised: 7 February 2021 | Accepted: 15 February 2021 DOI: 10.1111/are.15194 ORIGINAL ARTICLE Using the biochar produced from spend mushroom substrate to improve the environmental condition of aquaculture pond Jiunn-Cheng Lin 1 | Ann-Chang Cheng 2 * | Ya-Li Shiu 3 | Ya-Chuan Wong 4 | Shinn-Pyng Yeh 3 | Tohap Simangunsong 5 | Chun-Hung Liu 3,6 *Professor Ann-Chang Cheng (equal contribution as the 1 st author) 1 Division of Forestry Economics, Taiwan Forestry Research Institute, Council of Agriculture, Executive Yuan ROC, Taipei, Taiwan 2 Department and Graduate Institute of Aquaculture, National Kaohsiung University of Science and Technology, Kaohsiung, Taiwan 3 Department of Aquaculture, National Pingtung University of Science and Technology, Pingtung, Taiwan 4 Department of Applied Foreign Languages, National Taipei University of Business, Taipei, Taiwan 5 Department of Agribusiness, Faculty of Agriculture, Nusantara University of Manado, Sulawesi Utara, Indonesia 6 Research Center for Animal Biologics, National Pingtung University of Science and Technology, Pingtung, Taiwan Correspondence Chun-Hung Liu, Department of Aquaculture, National Pingtung University of Science and Technology, Pingtung 912, Taiwan, ROC. Email: chliu@mail.npust.edu.tw Funding information Taiwan Forestry Research Institute, Council of Agriculture, Executive Yuan R.O.C., Grant/Award Number: 109AS- 15.1.3-FI-G3 Abstract This study aims to probe the potential adsorbent of the biochar produced from spent mushroom substrate (SMS), of which pyrolysis temperature is 400°C, in improving the qualities of sediment and water quality in aquaculture pond. In the first trial, the adsorption of biochars to the ammonia-N and nitrite-N in water was evaluated, and the results showed that the SMS-derived biochars had the ability to adsorb ammonia- N rather than nitrite-N. Additionally, the adsorption capability of biochars to ammo- nia-N decreased as ambient salinity was increased. The SMS-derived biochars can also increase the pH of water. In view of the improvement of sediment, SMS-derived biochars was able to increase sediment pH and decrease the levels of ammonia-N and sulphite in sediments. In field trial, SMS-derived biochars was applied to a red claw crayfish farming. As the SMS-derived biochars had been thrown to the crayfish pond, pond conditions were improved because the pH of water and sediment increased, and the level of ammonia-N in water decreased, and the levels of ammonia-N and sulphide in sediment decreased. Therefore, the SMS-derived biochars was considered great potential as sorbents to adsorb the toxic substances, such as ammonia-N and sulphide in water and sediment. KEYWORDS biochar, sediment quality, spent mushroom bag, water quality