Mitigating Global Warming Potentials of Methane and Nitrous Oxide Gases from Rice Paddies under different irrigation regimes

Abstract

A field experiment was conducted in Bangladesh Agricultural University Farm to investigate the mitigating effects of soil amendments such as calcium carbide, calcium silicate, phosphogypsum, and biochar with urea fertilizer on global warming potentials (GWPs) of methane (CH 4 ) and nitrous oxide (N 2 O) gases during rice cultivation under continuous and intermittent irrigations. Among the amendments phosphogypsum and silicate fertilizer, being potential source of electron acceptors, decreased maximum level of seasonal CH 4 flux by 25-27 % and 32-38 % in continuous and intermittent irrigations, respectively. Biochar and calcium carbide amendments, acting as nitrification inhibitors, decreased N 2 O emissions by 36-40 % and 26-30 % under continuous and intermittent irrigations, respectively. The total GWP of CH 4 and N 2 O gases were decreased by 7-27 % and 6-34 % with calcium carbide, phosphogypsum, and silicate fertilizer amendments under continuous and intermittent irrigations, respectively. However, biochar amendments increased overall GWP of CH 4 and N 2 O gases.

Effect of biogas digested slurry-based biochar on methane flux and methanogenic archaeal diversity in paddy soil

“…Biochar has been reported to increase CH 4 emission even at almost 5-6 times higher C content to N-application in fields (Ali et al, 2013;. In addition, wide variation in soil CH 4 emission has been reported for soils with different chemical and physical properties, and under different water regimes (Ali et al, 2013;Cai et al, 1997).…”

“…Biochar, which is the product of the thermal degradation of organic materials in the absence of air (pyrolysis), is used as a soil amendment . Many studies have reported the beneficial effects of biochar in improving the soil quality and crop productivity (Ali et al, 2013;Saarnio et al, 2013;Inubushi, 2013, 2014a;Wang et al, 2012). The renewed interest in biochar comes primarily from its potential role as a long-term C sink in the soil, due to the recalcitrance of its microbial decomposition and chemical degradation (Schneider et al, 2011).…”

“…Most of the studies suggest that the addition of biochar can increase CH 4 emission (Ali et al, 2013;Knoblauch et al, 2011;Wang et al, 2012;Zhang et al, 2010). However, some of the published reports also state that the application of biochar may decrease CH 4 emission (Feng et al, 2012;Liu et al, 2011) or may not bring any significant change in CH 4 production (Xie et al, 2013).…”

“…Many available reports used either single concentration of biochar (Saarnio et al, 2013; or used very high doses of biochar (Feng et al, 2012;Zhang et al, 2010Zhang et al, , 2013 under varying concentrations of biochar (C content of biochar: N content of applied N-fertilizer, 15.55-62.26). Moreover, it has been reported that biochar may enhance CH 4 emission even at C content of biochar: N content of N-fertilizer, 5-6 ( Ali et al, 2013;. Another area of limitation from previous studies is the effects of biochar on soil microbial biomass in paddy fields especially under varying concentrations of biochar.…”

Biochar research activities and their relation to development and environmental quality. A meta-analysis

“…Similarly, surveyed funding activities revealed an intense support of biochar research on chemistry & fertility (22%), plant performance (33%), GHG & climate (22%) and technology (22%), but just 1.1% of mentioned funding sources originated from countries low on the human development index. Only three publications mentioned funding from countries with low human development index (Table 1; Ali et al 2012;Deal et al 2012;Sparrevik et al 2013;UNDP 2010). Each of these three studies was devoted to the area of plant performance and 2 of the 3 assessed also effects on chemistry & fertility, GHG & climate and technology.…”