Evaluating the effects of alternate wetting and drying (AWD) on methane and nitrous oxide emissions from a paddy field in Thailand

Abstract

Alternate wetting and drying (AWD) is a water-saving irrigation technique in a paddy field that can reduce the emission of methane, a potent greenhouse gas (GHG). It is being adopted to Asian countries, but different results are reported in literatures on methane, nitrous oxide emission, and rice productivity under AWD. Therefore, the local feasibility needs to be investigated before its adoption by farmers. The current study carried out a 3-year experiment in an acid sulfate paddy field in Prachin Buri, Thailand. During five crops (3 dry and 2 wet seasons), three treatments of water management were compared: continuous flooding (CF), flooding whenever surface water level declined to 15 cm below the soil surface (AWD), and site-specific AWD (AWDS) that weakened the criteria of soil drying (AWDS). Methane and nitrous oxide emissions were measured by a closed chamber method. Rice grain yield did not significantly (p < 0.05) differ among the three treatments. The amount of total water use (irrigation + rainfall) was significantly reduced by AWD (by 42%) and AWDS (by 34%) compared to CF. There was a significant effect of treatment on the seasonal total methane emission; the mean methane emission in AWD was 49% smaller than that in CF. The seasonal total nitrous oxide emission and the global warming potential (GWP) of methane and nitrous oxide did not differ among treatments. The contribution of nitrous oxide to the GWP ranged 39-62% among three treatments in dry season whereas 3-13% in wet season. The results indicate that AWD is feasible in terms of GHG emission mitigation, rice productivity, and water saving in this site, especially in dry season. ARTICLE HISTORY

Comparison of organic and inorganic fertilizer effect when combined with biochar and alternate wetting and drying on methane emission and yield of rice cultivation

“…It was re-flooded for many times (5 -6 times) with a huge water amount, resulting in the total water use is not much lower than CF. The water use reduction of AWD in this study is very low as compared to other studies (Chidthaisong et al, 2018, Tran et al, 2018 might be due to the soil type and evaporation rate in this study area. The further study to explain the constraints of AWD implementation in each soil type or each area zone should be conducted to recommend the farmers for adoption.…”

“…CH4 flux was calculated by using the equation given by Minamikawa et al (2015) that computed from linear regression of the gas concentration increase in the chamber headspace (ppmv) over the sampling time. The seasonal cumulative CH4 emissions were calculated by successive linear interpolation and numerical integration between sampling days, assumed that CH4 emissions on days without the measurement were according to a linear trend (Chidthaisong et al, 2018).…”

Site-specific feasibility of alternate wetting and drying as a greenhouse gas mitigation option in irrigated rice fields in Southeast Asia: a synthesis

“…In Jakenan, multiple aeration 7 days before the 1st and 2nd N fertilizer topdressing was implemented as AWDS in the first two seasons, and in the succeeding seasons, the threshold of re-flooding changed to 25 cm below the soil surface (Setyanto et al 2018). In Prachin Buri, the plots were re-flooded to 10-cm level under AWDS as compared to 5-cm level under AWD (Chidthaisong et al 2018). In Muñoz, AWDS was implemented as a 7-10-day-long single aeration (i.e., mid-season drainage) in the first two seasons.…”

“…They represent diversified paddy environments in Southeast Asia. Results from each site were reported in separate papers of this issue (Tran et al 2018;Setyanto et al 2018;Chidthaisong et al 2018;Sibayan et al 2018). They monitored the changes in soil carbon (C) content, which may be lost by intensive drainage events, in addition to CH 4 and N 2 O emissions under AWD and CF.…”

Effects of water management and cultivar on carbon dynamics, plant productivity and biomass allocation in European rice systems

“…panicle initiation and flowering), in order to promote high levels of grain production and the formation of good quality grain (Price et al, 2013). Numerous studies conducted throughout Asia and parts of North America have demonstrated that AWD can reduce CH 4 emissions by 35–90%, and improve overall water-use efficiency by 35–63% (Chidthaisong et al, 2018; Chu et al, 2015; Linquist Bruce et al, 2014; Rejesus et al, 2011; Setyanto et al, 2018; Tran et al, 2018; Yang et al, 2017).…”