Methane emission from Indonesian rice fields with special references to the effects of yearly and seasonal variations, rice variety, soil type and water management

摘要

Total amounts of CH emission from a Sumatra rice field were in the ranges 29·5–48·2 and 43·0–64·6 g CH m season for the plots with chemical fertilizer (CF-plot) and those with rice straw application (RS-plot), respectively. Nearly the same amounts of CH were emitted in the first and second half of the growth period, irrespective of rice straw application. The increase in the amounts of CH emission by rice straw application were from 1·3 to 1·6 times. There was no significant difference in the mean CH emission rates between rainy and dry seasons. Rain-fed conditions decreased the CH emission by 27–37% compared with continuously flooded conditions. Total amounts of CH emission from a rice field growing eight popular modern rice varieties in Indonesia were in the ranges 32·6–41·7 and 51·3–64·6 g CH m season for CF- and RS-plots, respectively. Total amounts of CH emission from four Sumatra rice fields with different soil types (a Typic Paleudult, a Typic Sulfaquent, a Typic Tropohumult and a Typic Tropopsament) were in the range 22·1 (a Typic Sulfaquent) to 53·4 (a Typic Tropohumult) g CH m season for CF-plots and from 26·7 (a Typic Sulfaquent) to 72·2 (a Typic Tropohumult) g CH m season for RS-plots. CH emission rates from Bali rice fields with soils of volcanic ash origin were very low; 3·5–7·7 and 5·3–14·3 g CH m season for CF- and RS-plots, respectively.Respective rice fields showed the specific productivity of grain production, and CH emission rates for 1 kg grain production were scattered widely from 8–11 and 11·24 g CH kg grain for rice fields of volcanic ash origin to 83 and 121 g CH kg grain for a Sumatra rice field for CF- and RS-plots, respectively. Water management was also an important factor in decreasing the CH emission rate. Copyright © 1998 John Wiley & Sons, Ltd.