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Abstract
The study was conducted in order to identify the ratio of water hyacinth combination with rubber sawdust substrate to grow oyster mushrooms which ensure that edible mushroom production with high yield and safety for comsumers. Using water hyacinth as substrate material is contribution to reduce its expanding and difficulty to control in Thua Thien Hue as well as to improve the environment. The experiment was arranged in a completely randomized block design (RCB) with 5 treatments and 3 replicates and each replicate is 15 bags. The total bags are 75 ones. Experimental results show that solving environmental problems as well as bringing income to people, the treatment II can be used with the mixing ratio: 64% sawdust + 25% water hyacinth + 5% rice bran + 5% corn flour + 1% CaCO3 for growing oyster mushrooms because the growth and development time is shorter 53.17 days, the yield is 36.44% in comparison with dry materials and the economic efficiency is 6.504 million VND/ 1 ton of raw materials which is higher than that other treatments combination with water hyacinth. The content of heavy metals in water hyacinth material and in the body of oyster mushroom are under the acceptance range.