Methane emission from a simulated rice field ecosystem as influenced by hydroquinone and dicyandiamide

A simple apparatus for collecting methane emission from a simulated rice fi eld ecosystem was formed. With no wheat straw powder amended all treatments with inhibitor(s) had so much lower methane emission during rice growth th an the treatment with urea alone (control), which was contrary to methane e mission from the cut rice-soil system. Especially for treatments with dicya ndiamide (DCD) and with DCD plus hydroquinone(HQ), the total amount of meth ane emission from the soil system and intact rice-soil system was 68.25-46. 64% and 46.59-41.78% of the control, respectively. Hence, DCD, especially i n combination with HQ, not only increased methane oxidation in the floodwat er-soil interface following application of urea, but also significantly enh anced methane oxidation in rice root rhizosphere, particularly from its til lering to booting stage. Wheat straw powder incorporated into flooded surfa ce layer soil significantly weakened the above-mentioned simulating effects . Regression analysis indicated that methane emission from the rice field e cosystem was related to the turnover of ammonium-N in flooded surface layer soil. Diminishing methane emissions from the rice field ecosystem was sign ificantly beneficial to the growth of rice. (C) 2000 Elsevier Science B.V. All rights reserved.