BACKGROUND: Silver grass(Miscanthus sinensis) No. 1 was developed to produce bio-ethanol, and then the silver grass-growing sector was established in Geumgang basin, Iksan, Jeonbuk, in 2011. However, it is high time to consider the other applicable possibility except using the bio-energy sources because of the drop in international oil prices. Therefore, there is the necessity of a scientific basis to use the silver grass instead of rice straw as the organic matter source that is used for soil improvement of the plastic film house cultivated around the sector.
METHODS AND RESULTS: The silver grass of 5, 10, 15 and 20 Mg/ha was applied and tilled before the watermelon was planted on the plastic film house. The control plot was treated with 10 Mg/ha with rice straw, and watermelons have been grown for 3 years(2017-2019). Soil aggregation, soil chemistry and the growth characteristics were investigated when the watermelon was harvested every year. Soil aggregation at the 2nd and 3rd year of watermelon harvest showed the same level at 5 Mg/ha and the control plot, and increased at the silver grass treatment plot of more than 10 Mg/ha, but there was statistically no difference between the plots. The nitrogen mineralization of silver grass tended to be similar in the control and 5 Mg/ha plot, but the silver grass treatment plot of over 10 Mg/ha showed low in nitrogen mineralization. Soil EC on harvest stage was proportional to the applied mass, but pH was in inverse. Content of soil organic matter, available phosphate, and exchangeable cations were increased with the continued use of silver grass. Watermelon weight found to be the best on more than 15 Mg/ha of silver grass, and the sugar content was highest when 10 Mg/ha of it was treated.
CONCLUSION: The use of the silver grass 10 Mg/ha annually as the organic source was effective in replacing rice straw while growing fruits and vegetables on the plastic film house.