Effect of root exudates of 2 rice varieties on methane emission in flooded paddy soil

Abstract

Preliminary pot experiment with flooded rice revealed that there was methane gas moved from flooded soil through rice plant to atmosphere. This amount of plant mediated methane accounted for 96% while via flooded soil was only 4 %. Continuation of the experiment was performed with rice varieties: Chainat 1 and Sakon Nakon in order to study the influence of root exudates on the amount of methane emission to atmosphere. It was found that total amount of root exudates from Chainat 1 (763.8 mg.C hill-1 season-1) was smaller than that from Sakon Nakon (1,120.3 mg.C hill-1 season-1). Meanwhile, the total methane released from Chainat 1 (463.5 mg hill-1 season-1) was lower with high significance than Sakon Nakon (690.9 mg. hill-1 season-1). Total methane emission of Chainat 1 accounted for 67 percent of Sakon Nakon. Results were concluded that Chainat 1 produced less root exudates and emitted less methane than Sakon Nakon. For both varieties, higher amount of root exudates induced higher amount of methane emission. Further experiment in similar manner should be performed by using various rice varieties for rice breeding improvement in the future, enabling to attain low quantity of root exudates, low plant mediated methane emission, but high rice yield.