Utilization of Spent Mushroom Substrate for Biochar Production and Its Impact on Arsenic Accumulation in Rice Grain

The rice straw waste was collected, and Pleurotus djamor (pink oyster) was cultivated. After harvesting the fruit bodies, the spent mushroom substrate (SMS) was collected and utilized to make biochar. A pot-based trial was carried out to examine the impacts of spent mushroom substrate biochar (SMSB) addition on the availability of arsenic (As) in soil and its buildup in rice tissues, respectively. In general, 0 (CK), 0.5%, and 1% SMSB were added into an As-contaminated soil before transplanting, respectively. The grain yield was also improved after 0.5% and 1% SMSB by 14.6% and 18.5%. The availability of As in soil did not changed after SMSB application. However, SMSB application reduced grain As concentration up to 27%. The SMSB application also improves the micronutrient concentration in rice grain. In order to accomplish the Sustainable Development Goals (SDGs), the two-way utilization of agrowaste in this study provides a sustainable substitute for agrowaste disposal.