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Methane emission from rice fields: Wetland rice fields may make a major contribution to global warming

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Abstract

Wetland rice fields have recently been identified as a major source of atmospheric methane. As in a natural wetland, flooding a rice field cuts off the oxygen supply from the atmosphere to the soil, resulting in anaerobic fermentation of soil organic matter. Methane is a major end product of anaerobic fermentation, released from submerged soils to the atmosphere by diffusion and ebullition and through the roots and stems of rice plants. Recent global estimates of emission rates range from 20 to 100 Tg/yr, corresponding to 6-29% of the total annual anthropogenic methane emission. This article discusses the importance of rice as staple food, the different environments in which rice is grown, and the methane fluxes in rice fields, along with the factors controlling the fluxes and options for mitigating methane release. 60 refs., 3 tabs.

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... Compared to submerged and moistened soil, fallow soil had the least amount of MC percentage as the rice fields were dry due to the least water supply during the second half of maturity phase and absence of water supply after harvesting until the next land preparation took place. ( (Neue, 1993). pH determines the growth, establishment, and the diversity of microorganisms in soil. ...
... At high MC, less efficient, anaerobic microorganism dominate the soil environment (Herron et al., 2009). Moreover, high MC favored microbial populations like methanogenic and methanotrophic microbes (Neue, 1993); hence, its MBC is higher than the MBC of fallow and lower then MBC of moistened soi Vol 6 Issue 7 water in the field, in which ions were dissolved in, was drained out of the field time to time during moistened period. Secondly, the remaining ions in the soil were homogeneously spread over the field due to water management practices. ...
... At high MC, less efficient, anaerobic microorganism dominate the soil environment (Herron et al., 2009). Moreover, high MC favored microbial populations like methanogenic and methanotrophic microbes (Neue, 1993); hence, its MBC is higher than the MBC of fallow and lower then MBC of moistened soi www.theijst.com ...
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Emission of CO2 from rice fields contributes to global warming. However, CO2 emission from the soil of rice fields varies with moisture content (MC) during different stages of rice cultivation: submerged (MC≥ 70 per cent), moistened (40 per cent MC), and fallow (20 per cent ≥ MC). Therefore, this study focuses on the effect of MC on CO2 emission from the soil of rice fields and investigates if average moisture conditions support high CO2 emission from soil. The research was conducted in three locations in Raozan, Bangladesh. Samples were collected from top soil (0-30 cm), where different stages of rice cultivation were observed. Organic carbon percentage (OC percentage), microbial biomass carbon (MBC), pH, and electric conductivity (EC) of samples were also tested. Results of the study implied that the highest CO2 emission occurred from submerged soil as a consequence of anaerobic fermentation that favored CO2 emission due to pH and high OC percentage. Also, the methane oxidation occurred as the submerged samples were exposed to oxygen (O2) during the sampling and experimental process. CO2 emission was lowest in fallow soil because of dry conditions that led dehydration of microorganisms. Moistened soil had an intermediate CO2 emission due to low OC percentage. Therefore, the study suggests that the dry conditions of soil result in the least amount of CO2 emission; hence, intermittent irrigation methods should be applied in rice fields to minimize the CO2 emission and water consumption. Keywords: Soil, rice, carbon dioxide, emission, moisture content
... Metana umumnya diproduksi oleh transmetilasi asam asetat dengan pengurangan karbon dioksida. Pada tanah masam, CH4 hanya akan terbentuk setelah digenangi selama lima minggu atau lebih (Neue, 1993 (Neue, 1993). Sisa-sisa tanaman dan gulma yang mudah terdekomposisi, serta bahan organik tanah merupakan sumber utama awal produksi CH4 (Toma et. ...
... Metana umumnya diproduksi oleh transmetilasi asam asetat dengan pengurangan karbon dioksida. Pada tanah masam, CH4 hanya akan terbentuk setelah digenangi selama lima minggu atau lebih (Neue, 1993 (Neue, 1993). Sisa-sisa tanaman dan gulma yang mudah terdekomposisi, serta bahan organik tanah merupakan sumber utama awal produksi CH4 (Toma et. ...
... Adanya tanaman akan memicu produksi CH4 yang lebih besar, terutama pada area rizosfer. Produksi metana meningkat pada daerah sekitar perakaran (Neue, 1993). Produksi CH4 berhubungan erat dengan eksudat C akar. ...
Article
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One of the main factors that play an essential role in controlling CH4 flux in wetlands is water management through the formation of aerobic and anaerobic soil conditions. Rice plants act as an intermediary medium for the CH4 flux release from the soil to the atmosphere through aerenchyma and trigger CH4 production. Therefore, this study had designed to study the effect of inundation and rice planting on CH4 emissions and the chemical properties of acid sulfate soil. The study had arranged by a randomized block design with two factors, i.e., inundation (not flooded/ponding water layer of 0.5 cm and flooded/ponding water layer of 5 cm) and rice planting (not planted and planted with rice). The CH4 flux in the flooded treatment was greater than that of the not flooded. Consumption of CH4 occurs in a not flooded condition which had indicated by a negative flux value. Rice cultivation triggered a large CH4 flux. Soil pH and soluble Fe were higher in flooded conditions, while soil Eh had lower.
... Kenaikan suhu yang oleh 'Intergovernmental Panel on Climate Change (IPCC)' diprediksi akan mencapai 1-3,5 o C pada akhir tahun 2100 (IPCC, 1992). Sebagai gambaran, kenaikan gas metana sebanyak 1,3 ppm CH 4 , dapat meningkatkan suhu atmosfer sebesar 1 o C (Neue, 1993). Emisi metan global tahunan diduga 420-620 Tg/ tahun dan konsentrasinya meningkat 1% hingga 1,7 ppmV (IPCC, 1992). ...
... Padi sawah dikenal sebagai sumber utama emisi gas metana, karena mengemisi gas metana cukup tinggi, yaitu antara 20 sampai dengan 100 Tg CH 4 /tahun (IPCC, 1992). Indonesia, dengan 10,6 juta hektar padi sawah, diperkirakan menyumbang sekitar % dari total emisi gas metana global (Neue, 1993). Produksi padi juga menghasilkan karbon dioksida yang muncul dari pembakaran sisa tanaman padi. ...
... Kemasaman tanah rendah menggiatkan mikroba dalam menghasilkan gas rumah kaca. Aktivitas mikroba metanogen dan nitrifikasi tinggi pada pH mendekati netral di tanah mineral (Neue, 1993;Wanget al.,1993;Granli dan Bockman, 1994). ...
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p>ABSTRACT Peatland development is increasingly becoming a strategic, both in terms of aspects of agronomy, and environmental aspects. Information magnitude of GHG emissions from drainage canals are important in the management of peat sustainability. Its objective is to determine the amount of GHG emissions from peatland drainage channels that are used for traditional rubber plantation. Gas sampling is done in the secondary drainage channel with a channel width of 5 m and 3 m wide tertiary. Sampling was performed six times with five points by using the lid closed cylinder. Sample was analyzed by gas chromatography flame ionization detector incorporates detector (FID) for the determination of the concentration of CH4. CH4 fluxes in peatland drainage channel width of 5 m is relatively higher than in the drainage channel width of 3 m in Jabiren peatlands of Central Kalimantan. GHG emissions in the channel width of 5 m was 542,20 ± 258,57 kg CO2-e yr-1 and 379,14 ± 260,7 kg CO2-e yr-1 of the channel width of 3 m.</p
... Because rice cultivation takes place in wetlands and flooded paddies which are very water-intensive, rice fields generate large amounts of methane, a greenhouse gas that is 21 times more potent than CO 2 and is associated with climate change (US Environmental Protection Agency, 2006). In fact, rice paddies are one of the major agricultural contributors to global methane emissions (Neue, 1993). In Wetland rice fields, rice cannot hold the carbon in anaerobic conditions, forcing the microbes in the soil to convert the carbon into methane that is released into the atmosphere (Neue, 1993). ...
... In fact, rice paddies are one of the major agricultural contributors to global methane emissions (Neue, 1993). In Wetland rice fields, rice cannot hold the carbon in anaerobic conditions, forcing the microbes in the soil to convert the carbon into methane that is released into the atmosphere (Neue, 1993). It is estimated that current agricultural methane emissions contribute about 10-15% of total global methane emissions (Neue, 1993). ...
... In Wetland rice fields, rice cannot hold the carbon in anaerobic conditions, forcing the microbes in the soil to convert the carbon into methane that is released into the atmosphere (Neue, 1993). It is estimated that current agricultural methane emissions contribute about 10-15% of total global methane emissions (Neue, 1993). Another estimate places the global contribution of methane emissions at 5-30% (WWF, 2005;Witte et al., 1993). ...
... 33% of the world's total methane emissions (Mosier et al., 1998). Methane is produced from decomposition of organic matter during anaerobically conditions (Wassmann et al., 2000) and is a GHG as it traps 23 (Yue et al., 2005) to 30 times more heat than CO 2 (Neue, 1993). Many studies on GHG emissions from flooded rice fields conclude that several drainage periods during the rice crop cycle will lower the total emission of methane from a flooded rice field (e.g. ...
... The use of different organic inputs might as well influence the emission rates. Compost applied to flooded fields will normally result in lower emissions of methane than applications of green manure and rice straw (Yagi & Minami, 1990; Neue, 1993) which are all typical farming inputs in resource poor areas. ...
... Resource poor farmers (RPF) who cannot afford to invest in mineral fertilizers rely on natural amendments such as compost and green manure. The most sustainable amendments would seem to be composts as compost only slightly increase methane emissions compared to green manure and rice straw (Neue, 1993; Yagi & Minami, 1990). Compost combined with mineral fertilizers decreased CH 4 emissions from rice fields in India twice as much as mineral fertilizers alone (Nayak et al., 2007) indicating that possible combinations of these two amendments would be ideal. ...
Thesis
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The System of Rice Intensification (SRI) has been adopted by many resource poor farmers throughout the world. In Cambodia approximately 80.000 farmers practice some sort of SRI and farmers are able to increase their rice yields with lower input costs. SRI is based on transplanting one seedling per hill as opposed to several for traditional rice and managing a drying and flooding regime of the soil leading to alternately anaerobic and aerobic conditions. This study targeted farmers in the ILFARM project (Improved Livelihood of Small Farmers) initiated by the Cambodian NGO CEDAC (Centre d’Étude et de Développement Agricole Cambodgien) and the Danish organization NORDECO (Nordic Agency for Development and Ecology) in Cambodia’s Prey Veng province. The objectives were to evaluate the effect of SRI on the farmers’ livelihood situation, potentials of increasing the soil Carbon pool and mitigation of greenhouse gases (CH4, N2O and CO2). The applied methods were interviewing households in the target group and soil sampling in the SRI fields for total Carbon and Nitrogen respectively. The target farmers were able to increase their rice yields significantly using SRI as compared to their traditional rice fields. Traditional rice fields yielded 2.19 t ha-1 and SRI fields yielded 3.53 t ha-1 respectively. The main reason seems to be the use of only one seedling per hill thus reducing the competition for nutrients. The use of water management was not practiced due to no or little irrigation facilities. Main constraints for further development of SRI would be the lack of high amounts of biomass. In order to cope with this, the ILFARM project will however supply the farmers with 500.000 trees in order to increase the amount of available on site biomass. It was estimated that such measures could increase the soil C pool with roughly 116 kg C ha-1 year-1. The SRI conducted by the target farmers did not have large influences on mitigation as farmers were not able to manage a fluctuating water table due to no irrigation facilities. However if all concepts of SRI is followed this could decrease emissions of especially CH4. SRI appears to be a suitable and sustainable way of growing rice for resource poor farmers and in addition it carries the potentials of being able to increase soil fertility through an increased C pool and mitigation possibilities of greenhouse gases.
... Mobility of gas in the active layer is known as diffusion. It is a purely physical and slow process of CH 4 emission and accounts for very less amount of total CH 4 flux from soil due to its low solubility in water (Neue, 1993). The diffusion of CH 4 is negligible in clay soil and highest in sandy soil due to differences in pore-space (Neue, 1993). ...
... It is a purely physical and slow process of CH 4 emission and accounts for very less amount of total CH 4 flux from soil due to its low solubility in water (Neue, 1993). The diffusion of CH 4 is negligible in clay soil and highest in sandy soil due to differences in pore-space (Neue, 1993). In deepwater rice diffusion is active only in upper water column (Neue, 1993). ...
... The diffusion of CH 4 is negligible in clay soil and highest in sandy soil due to differences in pore-space (Neue, 1993). In deepwater rice diffusion is active only in upper water column (Neue, 1993). Diffusion also limits the rate of plant-mediated CH 4 transport to the atmosphere by achieving the threshold level of CH 4 partial pressure in the rhizosphere (Denier van der Gon and Breemen, 1993). ...
... The highest emission at the stage of rice flowering (55 th -65 th day) when soil continuously flooded. During this stage, rice roots and stems developed, then released CH 4 from the soil into the air through the roots system and the stems of the rice was high [19,15]. The lowest CH 4 emission was found at the stage of 35 th -45 th and the stage of rice ripe (75 -95 days). ...
... Thus, the CH 4 emission from the rice fields of this research was agreed with the previous studies. In addition, the CH 4 mission increased due to the organic decomposition of rice leaves [19]. The factors e.g. ...
Article
This study was carried out to investigate the effects of irrigated water management to CH4 emission from the paddy fields. It was designed with (1) continuous flooding (CF) and (2) alternate for wetting and drying (AWD) which the water level was controlled + 5 cm and ± 5 cm than the soil surface, respectively at Cho Moi, Chau Thanh, Thoai Son and Tri Ton districts of An Giang province. The soil samples were collected to determine their physico-chemical properties. CH4 was collected weekly during the rice cultivation, and the rice yield was determined at the harvest. The results showed that pH 4.55 – 5.93, EC 105 – 175 µS.cm-1, organic matter 3.21 – 3.94 %, CEC 25.05 – 33.33 cmol.kg-1 of the soil were suitable for rice growth. The average rice yield was about 4.5 - 6.52 ton.ha-1. CH4 emissions of the AWD decreased 59.1 % compared to the CF which was 14.6 mg C-CH4.m-2.h-1. Therefore, the AWD is better than the CF in term of reducing CH4 emissions to the environment.
... It is grown on every continent except Antarctica. By the 1990's rice was providing 35% to 59% of the total calories consumed by nearly 2.7 billion people in Asia (Neue, 1993). Peng et al. (1999) quoted that world rice production would need to be at least 600 million tons by 2025, an increase of 266 million tons above 1995 production just to maintain current nutrition levels. ...
... Peng et al. (1999) quoted that world rice production would need to be at least 600 million tons by 2025, an increase of 266 million tons above 1995 production just to maintain current nutrition levels. This increase will likely not be sufficient to alleviate current malnutrition in many of the rice dependent cultures (Neue, 1993). In areas where it is virtually the sole source of calories it is seldom grown in rotation with other crops. ...
... and an increasing number of extreme weather events), it needs more challenge in India as productivity of most crops is below than the world average. System of Rice Intensification (SRI) proved better for sustainable productivity in rice throughout the world but it needs research proof in different agro-ecosystems to find out the proper reasons and concepts (12-15 days seedling can give more tillers 8 ; balance nutrition helps to convert amino acid to more protein and thereby reducing the surplus sugar and finally insect pest or pathogen attack 9 ; alternate wetting and drying helps to save water without productivity loss 10 ; botanical pesticides coming up as an alternate of hand weeding 11 ; reduces the GHG like N 2 O, CH 4 etc. 12 by more mineralization of nitrogen) and ultimately increase the rice productivity in a sustainable way. In light of the above mentioned point regarding water management, it is highly needed to find out the actual amount of water saving in SRI over TTR and the yield performances of the rice in these methodologies in the Gangetic inceptisol. ...
Article
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The System of Rice Intensification (SRI) shows promise for substantially raising rice productivity besides offering savings of major inputs viz. water, seed, labour and increasing soil health status. Field experiment was conducted at the Viswavidyalaya farm, Mohanpur during summer 2014-15 and 2015-16 on water management in transplanted puddle rice cv. IET 4786 to find out the advantages of SRI over TTR (Traditional transplanted rice) in respect to water saving and rice productivity. Four treatments viz. T1- FCP (Farmers' common practices: 3-5 cm of standing water throughout the crop cycle), T2- Only 2-3 cm WS (2-3 cm of standing water throughout the crop cycle), T3- HC (Irrigation at soil hair crack stage) and T4- AWD (Irrigation at soil hair crack stage during vegetative phase + 2-3 cm of standing water at active tillering, panicle initiation and flowering stage only) were used in randomised block design replicated six times. The results revealed that average yield increase in 2015-16 than 2014-15 was 2.56 %. Irrigation through AWD methodology resulted 32.78 % water savings in comparison to FCP. The other two treatments, irrigation at hair crack stages and only 2-3 cm WS showed 53.90 and 21.23 % water saving over farmers’ common practice respectively. For producing one kg of rice the water requirement in AWD, HC and only 2-3 cm WS was 1217, 1037 and 1580 litre respectively, which was lower than of FCP (1891 litre). Therefore it could be concluded that in SRI irrigating through AWD methodology showed 33 % water saving and an average of 7.62 % productivity increase in comparison to FCP in traditional transplanted rice cultivation.
... A decomposição anaeróbia de material orgânico em campos de arroz inundado produz metano, que escapa para a atmosfera principalmente através de transporte mediado por plantas de arroz (IPCC, 2006). O arroz é uma planta semiaquática provida de aerênquima, tecido vascular que favorece a troca de gases entre as raízes e os tecidos acima da superfície da água, permitindo o transporte de O 2 atmosférico para as raízes, e de outros gases, como o CH 4 produzido no solo anaeróbio para a atmosfera (Neue, 1993). hectares. ...
... In flooded rice methanogens bacteria consume soil organic carbon and emit CH 4 (Nazaries et al. 2013; Penning and Conrad 2007). Methane produce by methanogens in rice soil, generally emits to atmosphere by three (diffusion, ebullition and aerenchymal transportation) possible mechanisms (Green 2013; Tokida et al. 2013; Das and Baruah 2008; IPCC 1996; Neue 1993). In rice soil N 2 O is produce by both biological (nitrification and denitrifcation) and chemical decomposition process (Lan et al. 2014; Baggs 2011; Ussiri and R. Lal 2007; Freney 1997; Bremner 1997). ...
Article
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Rice fields are significant contributors of greenhouse gases mainly methane and nitrous oxide to the atmosphere. Increasing concentrations of these greenhouse gases play significant role in changing atmospheric chemistry such as mean air temperature, rainfall pattern, drought, and flood frequency. Mitigation of greenhouse gases for achieving sustainable agriculture without affecting economical production is one the biggest challenge of twenty first century at national and global scale. On the basis of published scientific studies, we hereby assess the use of nitrification inhibitors for greenhouse gas mitigation from rice soil. Biologically oxidation of ammonium to nitrate is termed as nitrification and materials which suppress this process are known as nitrification inhibitors. Soil amendment by addition of certain nitrification inhibitors such as neem oil coated urea, nimin-coated urea; dicyandiamide, encapsulated calcium carbide, and hydroquinone reduce cumulative methane and nitrous oxide emission from rice. Firstly, these inhibitors reduce nitrous oxide emissions both directly by nitrification (by reducing NH4+ to NO3-) as well as indirectly by de-nitrification (by reducing NO3- availability in soil). Secondly, methane emission from rice soil can be reduced by enhancing methane oxidation and suppressing methane production and further by reducing the aerenchymal transportation through rice plant. Application of some of the nitrification inhibitors such as calcium carbide and encapsulated calcium carbide reduce methane production by releasing acetylene gas which helps in reducing the population of methanogenic microbes in the soil. Application of nitrification inhibitors also helps to maintain soil redox potential at higher level subsequently reducing cumulative methane emission from soil. Plant derived organic nitrification inhibitors (neem oil, neem cake, karanja seed extract) are eco-friendly and possess substantial greenhouse gas mitigation potential from rice. In the current scenario of global warming and environmental pollution, application of organic plant derived nitrification inhibitors is much needed for sustainable agriculture.
... The adverse effect of salinity on microbial methane production is known for a long time (Koyama et al. 1970) and attributed to the sulfate content of sea water. Methanogens have to compete with sulfate-reducing bacteria for hydrogen (Neue 1993). Denier Van Der Gon and Neue (1995) showed that an increase in the salt content of pore water to an electrical conductivity of 4 mS cm −1 led to a 25% reduction in the methane emission rate compared with a control plot. ...
Article
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This study comprises a set of methane emission measurements in rice fields located in the four agro-ecological zones of the Mekong River Delta (MRD), namely the zones with (i) alluvial soils, (ii) salinity intrusion, (iii) deep flood, and (iv) acid sulfate soils. These zones have very distinct bio-physical conditions and cropping cycles that will affect methane emissions in various forms. Our study includes comprehensive mapping of these zones as well as an overview of rice statistics (activity data) at provincial level for each cropping season. Emission data were obtained by the closed chamber method. The available data set comprises 7 sites with 15 cropping seasons. Mean emission rates showed large variations ranging from 0.31 to 9.14 kg CH4 ha⁻¹ d⁻¹. Statistical analysis resulted in weighted means for all zones that we use as zone-specific CH4 emission factors (EFz) in the context of the IPCC Tier 2 approach. The lowest EFz was computed for the saline accounting for 1.14 kg CH4 ha⁻¹ d⁻¹ (confidence interval: 0.60–2.14). The EFz values of the alluvial and acid sulfate zones were 2.39 kg CH4 ha⁻¹ d⁻¹ (2.19–4.13) and 2.78 kg CH4 ha⁻¹ d⁻¹ (2.65–3.76), respectively, which indicated that they were not different from each other derived from their confidence intervals. The deep flood zone, however, required a season-specific, assessment of EFz because emission in the autumn–winter cropping season, corresponding to the wet period, was significantly higher (9.14 kg CH4 ha⁻¹ d⁻¹ (7.08–11.2)) than the other seasons (2.24 kg CH4 ha⁻¹ d⁻¹ (1.59–3.47)). Although these emission factors correspond to baseline water management and do not capture the diversity of farmers’ practices, we see the availability of zone-specific data as an important step for a more detailed assessment of Business as Usual emissions as well as possible mitigation potentials in one of the most important rice growing regions of the world.
... Methane generation involves methanogenic bacteria such as Methanosarcina, Methanobacterium, and Methanococcus (Neue and Roger 1994). Most of methanogenic bacteria are neutrophylic with optimum pH in range of 6-8 (Neue 1993). Methane emission from flooded rice soils occurs through plant-mediated rice plant aerenchyma, ebullition, and diffusion (Conrad 1996). ...
Article
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p>Incorporation of rice straw into soil is a common practice to improve soil productivity and increase inorganic fertilizer availability. However, this practice could contribute to methane (CH4) emission; one of the greenhouse gases that causes global warming. Nitrification inhibitors such as neem cake and carbofuran may reduce methane emission following application of rice straw. The study aimed to evaluate the application of rice straw and nitrification inhibitor to methane emission in rainfed lowland rice system. A factorial randomized block design was used with three replications. The first factor was rice straw incorporation (5 t ha-1 fresh straw, 5 t ha-1 composted straw), and the second factor was nitrification inhibitor application (20 kg ha-1 neem cake, 20 kg ha-1 carbofuran). The experiment was conducted at rainfed lowland in Pati, Central Java, during 2009/2010 wet season. Ciherang variety was planted as direct seeded rice with spacing of 20 cm x 20 cm in each plot of 4 m x 5 m. The rice straw was treated together with soil tillage, whereas nitrification inhibitor was applied together with urea application. Parameters observed were methane flux, plant height, plant biomass, grain yield, organic C content, and bacterial population in soil. The methane flux and soil organic C were measured at 25, 45, 60, 75, and 95 days after emergence. The results showed that composted rice straw incorporation significantly emitted methane lower (73.2 ± 6.6 kg CH4 ha-1 season-1) compared to the fresh rice straw (93.5 ± 4.0 CH4 ha-1 season-1). Application of nitrification inhibitors neem cake and carbofuran reduced methane emission as much as 20.7 and 15.4 kg CH4 ha-1 season-1, respectively. Under direct seeded rice system, methane flux level correlated with plant biomass as shown by linear regression of Y = 0.0015 X + 0.0575 (R2 = 0.2305, n = 27). This means that higher plant biomass produced more methane flux. The study indicates that application of nitrification inhibitors such as neem cake is prospective in decreasing methane emission from direct seeded rice cropping. <br /
... This water regime allows rice residues and organic matter to decompose, although the rate of decomposition is slower than under well-watered aerobic conditions (Ladha et al. 2011). In addition, very low redox potentials promote the anaerobic fermentation of organic matter in which CH 4 is one of the end products (Neue 1993;Mosier et al. 2004). ...
Article
Irrigated rice cultivation is a major source of greenhouse gas (GHG) emissions from agriculture. Methane (CH4) and nitrous oxide (N2O) are emitted not only throughout the growing season but also in the fallow period between crops. A study was conducted for two transition periods between rice crops (dry to wet season transition and wet to dry season transition) in the Philippines to investigate the effect of water and tillage management on CH4 and N2O emissions as well as on soil nitrate and ammonium. Management treatments between rice crops included (1) continuous flooding (F), (2) soil drying (D), (3) soil drying with aerobic tillage (D + T), and (4) soil drying and wetting (D + W). The static closed chamber method was used to measure CH4 and N2O fluxes. Soil nitrate accumulated and N2O was emitted in treatments with soil drying. Nitrate disappeared while ammonium gradually increased after the soil was flooded during land preparation, indicating net nitrogen mineralization. N2O emissions were highest in both transition periods in D + W (437 and 645 µg N2O m⁻² h⁻¹). Methane emissions were significant in only the F treatment. The highest global warming potential (GWP) in the transition between rice crops occurred in F, with CH4 contributing almost 100% to the GWP. The GWP from other treatments was lower than F, with about 60–99% of the GWP attributed to N2O emissions in treatments with soil drying. The GWP in the transition between rice crops represented up to 26% of the total GWP from harvest to harvest. This study demonstrates that the transition period can be an important source of GHG emissions with relative importance of CH4 and N2O depending on the soil water regime. Therefore, the transition period should not be disregarded when estimating GHG emissions for rice cropping systems.
... Borell et al. (1997) reported that rice grown on raised beds under saturated soil condition reduced International Journal of Tropical Agriculture © Serials Publications, ISSN: 0254-8755 the amount of water use by 32% over conventional methods. Drying for short duration at the end of the tillering stage and just before flowering followed by flooding improved the yield of wetland rice with reduced water supply (Neue, 1993). ...
Article
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Longer duration and higher frequency of dry spells in monsoon season is one of the major causes of low productivity and failure of rice crops in India. Keeping this in view, a field experiment was conducted to study the response of kharif rice to supplemental irrigation under drip and surface irrigation methods in a sub-humid tropical climate of eastern India. Water was applied to rice after three days of drainage of standing water in field. Different drip irrigation (DI) treatments imposed were irrigation at 125% crop evapo-transpiration (ETc), 100% ETc and 75% ETc, at 1.0 m lateral layout (lateral-to-lateral distances) whereas surface irrigation (SI) was applied through flexible hose-pipe to rice plots. Rain-fed rice was taken as control treatment for comparison. The irrigation water applied under different DI treatments varied from 108 mm to 179 mm whereas it was 250 mm under SI. The highest vegetative growth of rice was recorded under DI at 125% ETc, whereas higher grain yield was harvested from SI which was statistically at par with that under DI at 100% ETc and 125% ETc. However, the maximum irrigation water use efficiency was obtained from DI at 100% ETc. The grain yield of drip-irrigated rice was 26% higher than rain-fed rice. The effect of irrigation on available nutrients (N, P and K) in soil was statically (p>0.05) insignificant.
... It comes from sources such as combustion of fossil fuel and livestock production. Additionally, rice fields have recently been discovered as large methane emitters (Neue 1993). ...
Technical Report
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This report was drafted, at the request of the United Nations World Food Programme West Africa Bureau (WFP), at Columbia University’s School of International and Public Affairs Program on Environmental Science and Policy. The report provides information on the impacts of global climate change on livelihoods and food security, as well as recommendations for the WFP to inform their adoption of adaptation and mitigation strategies. The program recommendations are organized according to vulnerability categories that the United Nations Environment Program (UNEP) has designated as being quite relevant for climate change: flooding, drought and desertification, deforestation, and direct impacts on food security.
... Furthermore, drainage techniques must be managed carefully to prevent losses of nitrogen corresponding with nitrous oxide (N 2 O) emissions, a very active greenhouse gas (Wassmann et al., 1993a;Abao et al., 2000;Zou et al., 2005). These emissions could be increased through nitrification and denitrification processes, which are associated with soil drying and wetting, respectively (Neue, 1993;Bronson et al., 1997;Corton et al., 2000). ...
Article
Rice fields contribute substantially to global warming of the atmosphere through emission of methane (CH4). This article reviews the state of the art of factors affecting CH4 emissions in rice fields, focusing on soil organic matter content and water management practices. A quantitative relationship between these factors was established through a meta-analysis based on a literature survey. This relationship can be useful to update emission factors used to estimate CH4 in the National Emission Inventories. Methane emissions in rice fields can be as much as 90% higher in continuously flooded rice fields compared with other water management practices, independent from straw addition. Water management systems that involve absence of flooding in total or for part of the growing period such as midseason drainages, intermittent flooding, and percolation control, can reduce CH4 emissions substantially. Moreover, CH4 emissions increase with the amount of straw added up to 7.7 t/ha for continuously flooded soils and up to 5.1 t/ha for other water regimes. Above these levels, no further increase is produced with further addition of straw. With regard to rice straw management mitigation strategies, recommended practices are composting rice straw, straw burning under controlled conditions, recollecting rice straw for biochar production, generation of energy, to be used as a substrate, or to obtain other byproducts with added value. This review improves the understanding of the relationship between straw application rate, water regimes, and CH4 emissions from rice fields to date. This relationship can help to select the most appropriate management practices to improve current mitigation strategies to reduce atmospheric CH4.
... Rice (Oryza sativa L.) is the only major grain crop that is grown almost exclusively as food. More than 90% of the world's rice is produced in Asia (Neue, 1993). The Philippines was considered as one of the largest rice producers in the world, accounting for 2.8% of global rice production (Albutra et al., 2012). ...
Article
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Stem borers are one of the most important insect pests that could infest rice plants from seedling to maturity and thus play a major role in crop losses. The study of its mandible that is used in feeding of stem borer would help understand the mechanisms and variations that could affect the adaptation and modification affecting severity of infestation. In this study, the mandible of two population of stem borers, the yellow stem borer (Scirpophaga incertulas and the striped stemborer (Chilo suppressalis) in three rice varieties IR-66, Pioneer 77 and Bigante were used to analyze the adaptation with regards to mandible shape in relation to rice variety in the same geographical location using outline-based (elliptic Fourier) geometric morphometric (GM) analysis to determine the shape variations in the left and right mandible of two population of stem borers. Further, scatter plot method was used to illustrate variations in the shapes of the mandibles between populations. Results of this study showed symmetrical shape variations in the right and left mandible of the two species of stem borers and their accumulation to the kind of rice plant varieties were not selective. Keywords - Animal ecology, stem borer, mandible, geometric morphometric analysis,Philippines
... Rice (Oryza sativa L.) is the only major grain crop that is grown almost exclusively as food. More than 90% of the world's rice is produced in Asia (Neue, 1993). The Philippines was considered as one of the largest rice producers in the world, accounting for 2.8% of global rice production (Albutra et al., 2012). ...
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In this paper, the researchers document for the very first time in detail the moray eel capture fishery in the seagrass beds of Siquijor Island, Central Philippines. The process of deploying the bamboo traps, gathering of baits, andcatch-per-unit effort (CPUE), income-per-unit effort (IPUE), and the possible impact of an increasing number of moray eel fishers are also discussed. The researchers noted a very low average CPUE of 1.32±0.19 S.E. kg/person/hr and a corresponding Income-per-unit effort (IPUE) of 59.75±9.9 S.E.. Philippine Pesos/person/hour. Sustainable fishing practices of catching moray eels are also highlighted. Apparently, two new records of muraenid eels of the Genus Gymnothorax for the Philippines are also briefly annotated. Keywords - Fishery, Moray eel, Catch Assessment, Siquijor Island, Philippines, Southeast Asia
... Cassava has potential to meet both demand sites. Neue [11] reported that to produce food from rice wetland was not ecologically sound, due to methane emission from rice wetland culture. Nguyen [12] indicated that aside in lowland rice had significant contribution as source of methane, in upland reducing forest to be converted into rice field also increase the area of degraded forest. ...
Article
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Cassava (Manihot esculenta Crantz) is the most essential source of carbohydrate. As a source of carbohydrate, cassava is used for food, feed industries as well as potential to be utilized as raw material for bio-fuel. To anticipate the greater demand for food, feed and renewable fuel expanding harvest area as well as by implementing new innovation in the form of introducing high yielding varieties with inorganic and organic fertilizers to improve soil fertility is strongly recommended.
... In the global context, Harrison and Aiyer noted the potential for CH 4 release from rice fi elds as early as 1913 (Neue 1993 Deforestation and the loss of agro-biodiversity leads to a decrease in soil organic matter so the desertifi cation has begun. More chemical fertilizer is needed to achieve the same production. ...
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The increase in the concentration of greenhouse gases (GHGs) in the atmosphere is widely believed to be causing climate change. It affects agriculture, forestry, human health, biodiversity, and snow cover and aquatic life. Changes in climatic factors like temperature, solar radiation and precipitation have potential to influence agrobiodiversity and its production. An average of 0.04°C/ year and 0.82 mm/year rise in annual average maximum temperature and precipitation respectively from 1975 to 2006 has been recorded in Nepal. Frequent droughts, rise in temperature, shortening of the monsoon season with high intensity rainfall, severe floods, landslides and mixed effects on agricultural biodiversity have been experienced in Nepal due to climatic changes. A survey done in the Chitwan District reveals that lowering of the groundwater table decreases production and that farmers are attracted to grow less water consuming crops during water scarce season. The groundwater table in the study area has lowered nearly one meter from that of 15 years ago as experienced by the farmers. Traditional varieties of rice have been replaced in the last 10 years by modern varieties, and by agricultural crops which demand more water for cultivation. The application of groundwater for irrigation has increased the cost of production and caused severe negative impacts on marginal crop production and agro-biodiversity. It is timely that suitable adaptive measures are identified in order to make Nepalese agriculture more resistant to the adverse impacts of climate change, especially those caused by erratic weather patterns such as the ones experienced recently. DOI: http://dx.doi.org/10.3126/hn.v11i1.7206 Hydro Nepal Special Issue: Conference Proceedings 2012 pp.59-63
... Per kg, CH4 emissions contribute about 25 times more to GWP than those of CO2. Continuous flooding of rice paddies to grow irrigated rice makes it one of the major sources of methane in the agricultural sector (Neue 1993). Flooded rice paddies account for 6 to 29% of the CH4 for which humans are responsible (http://www.ciesin.columbia.edu/TG/AG/ricecult.html). ...
... Irrigated lowland rice paddies are one of the principal anthropogenic sources of CH 4 , representing approximately 5-10% of the worldwide CH 4 source (Kirk and Bickert 2004;Matthews et al. 2000). In lowland irrigated rice, flooding creates anaerobic soil condition which helps CH 4 production from the decomposition of both native and externally added organic materials (Neue 1993;Wassmann et al. 2000). In an estimate, it was observed that methane emission was 500-600 Tg CH 4 year −1 globally (Dlugokencky et al. 2011). ...
Article
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Lowland tropical rice-rice system has a unique micrometrological characteristic that affects both energy component and net ecosystem energy. Periodic and seasonal variations of methane (CH4), carbon dioxide (CO2), and energy exchange from irrigated lowland rice-rice ecosystem were studied using open-path eddy covariance (EC) system during the dry (DS) and wet (WS) seasons in2015. Concurrently, the manual chamber method was employed in nitrous oxide (N2O) measurement efflux. Cumulative net ecosystem carbon exchange (NEE) was observed highest (− 232.55 g C m−2) during theWS and lowest (− 14.81 g C m−2) during wet fallow (WF). Similarly, the cumulative net ecosystem methane exchange (NEME) was found highest (13,456.5 mg CH4 m−2) during the WS and lowest (2014.3 mg CH4 m−2) during the WF. Surface energy fluxes, i.e., sensible (Hs) and latent heat (LE) fluxes, showed a similar trend. With the advancement of time, the ratio of ecosystem respiration (Re) and gross primary production (GPP) increased. The cumulative global warming potential (GWP) for the two cropping seasons including two fallows was 13,224.1 kg CO2 equivalent ha−1. The GWP and NEME showed a similar trend as soil enzymes and labile carbon pools in both seasons (except GWP at the harvesting stage in the wet season). The mean NEE exhibited a more negative value with decrease in labile pools from panicle initiation to harvesting stage in the WS. Soil labile C and soil enzymes can be used as an indicator of NEE, NEME, and GWP in lowland rice ecology.
... In this stage, the CH 4 emission also decreased gradually since soil became dry. In the flowering stage (61-75 days after sowing), CH 4 emission increased insignificantly slightly through the root systems and stems [11]. After the flowering stage, CH 4 emission decreased until the end of crop because the water level in the field was low for rice ripening and for introduction of machine to the field for easily harvest. ...
Article
Rice cultivation causes the emission of CH4 consequenced to the global warming. Reduction of irrigation in rice cultivation is not only saving water resources but also reducing greenhouse gases emission. The objectives of this study was to determine impacts of water management on the emission of CH4 and rice yield. Experiment was conducted in field conditions in An Giang province, Viet Nam with three treatments as continuous flooding (CF), An Giang Alternative Wetting and Drying (AAWD) which is mostly applied by farmers in An Giang province-Viet Nam, and Alternate Wetting and Drying (AWD). Water levels in the field +5 cm, ± 5 cm and -15 cm were controlled higher, fluctuated and lower than soil surface, respectively for CF, AAWD and AWD. CH4 emission determined every week during 13 weeks of the experiment. Rice yield was determined in 1 m2 at the end of the experiment. The results showed that AWD and AAWD, respectively decreased 78.7 % (p < 0.05) and 6.8 % (p > 0.05) CH4 emission compared to the CF 11.9 mg CH4/m2/h. The rice yield of CF was 6.32 ton/ha lower than AAWD 7.8 ton/ha (p < 0.05) but not different with AWD 6.67 ton/ha. AAWD had higher rice yield but same emission than the CF. Farmers in An Giang province should consider application of AWD in rice cultivation in term of saving water and reduction of CH4 emission.
... Anaerobic soil conditions lead to increased CH 4 emissions compared with crops grown in upland, aerobic systems [2,3]. CH 4 generated in anaerobic soils by the microbial decomposition of organic matter is a process, which typically begins in rice fields two weeks after flooding [4]. Therefore, if water management practices are altered, there presumably will be corresponding changes in methane emissions. ...
... Methylophilus also oxidize methanol to formaldehyde, which is catalysed by classical methanol dehydrogenase and stimulated by ammonium ions, and uses methanol as a source of carbon and energy (Dai et al., 2019;Kaparullina et al., 2018;Xia et al., 2015). This methanol might be generated through the oxidation of dissolved methane that diffused from anaerobic wetland soils (Neue, 1993). ...
Article
An integrated rice–fish farming system is an efficient technique used to maintain water quality and rice/fish productivity. In addition to fish and rice plants that have mutually beneficial ecological roles, bacteria play important roles in maintaining water quality and soil fertility. Therefore, this study investigated the diversity and dynamic change in the bacterial community composition of water and sediment in an integrated rice–fish farming system using a high-throughput sequencing approach. The 16S rRNA gene of bacteria was amplified, and the IonS5™XL sequencing platform was used to identify bacterial community during the cultivation period. The results demonstrated that fishpond, rice field and trench sediment samples were dominated by the phyla Proteobacteria (60.9%–64.4%), Acidobacteria (8.7%) and Chloroflexi (6.3%), whereas water samples were dominated by the phyla Proteobacteria (65.7%), Bacteroidetes (17.1%) and Actinobacteria (8.5%). The dynamics of the bacterial community composition of the water and sediment samples were clearly observed at phylum and genus levels respectively. Water temperature (34.67°C) and ammonia-nitrogen content (0.38 mg L⁻¹) at the early stage of cultivation correlated with the abundances of Actinobacteia and Cyanobacteria at the phylum level and Acinetobacter at the genus level. Furthermore, several bacterial genera could potentially contribute to the biogeochemical cycle. In particular, Sorangium was involved in organic matter degradation, Methylophilus was implicated in nitrification, Novosphingobium and Methylotenera were essential for denitrification, and Desulfobacca was important for sulfate reduction. This study improved our understanding of the bacterial community in the integrated rice–fish farming system and provided data for further development.
... CH 4 emission showed a significant (p < 0.0001) negative Fig. S2). Eh dropped gradually with the incubation period up to 35 days, due to the decomposition of organic matter under continuous submergence conditions (Neue, 1993) by the methanogenic bacteria. DO is consumed during the decomposition of organic matter, which resulted in lowering of soil Eh (Hussain et al., 2015). ...
Article
Methane (CH4) emissions are responsible for the higher global warming potential of rice cultivation. There are scattered reports on the use of chemical interventions for reducing CH4 emissions from rice. A laboratory study was carried out to estimate the CH4 mitigation potential of oxygen releasing chemicals such as magnesium peroxide (MgO2) and calcium peroxide(CaCO2), chelating agent ethylene diamine tetra acetic acid (EDTA), nitrification inhibitors thiourea, and neem oil, limus (urease inhibitors), phosphogypsum (PG) a byproduct of phosphate fertilizer industry and ammonium sulfate (AS). The cumulative CH4 emission from soil reduced by 2.0 to 32.3% under the different treatments during the 45 days’ incubation study. Subsequently, four chemicals having the highest CH4 reduction potential i.e. PG, EDTA, AS, and MgO2 were further evaluated for the mitigation of CH4 and their concurrent impact on nitrous oxide (N2O) emission in a two-year experiment growing rice. PG, EDTA, AS, and MgO2 significantly (p=0.0025) decreased CH4 emissions by 9.3 -27.5% as compared to the control. The cumulative N2O emission were significantly lower by 13.9% under PG as compared to control. The global warming potential decreased by 6.8% with MgO2 to 23.6% with PG. The grain yield increased by 3.1 to 11.2% under the different treatments. The greenhouse gas intensity (GHGI) was the highest in control (0.309) and lowest in PG (0.212). The findings suggest that PG, EDTA, AS, and Mg can be used to plummet the global warming potential of irrigated rice soils without any yield penalty. More research is required to be undertaken to evaluate the impact of these chemicals from the perspective of food security in the farmers’ fields.
... Previous studies, however, have indicated soil texture as an interactive factor in the production and consumption of CH 4 (Oo et al., 2015;Brye et al., 2013). Coarse textures, such as loamy soils, have been reported to release more CH 4 than finer textures, such as clayey soils, likely due to the greater abundance of macropores in loamy soils that entrap less CH 4 for re-oxidation (Neue, 1993;Rogers et al., 2014). Although not significant, the positive correlation between CH 4 emissions and BD indicated that as BD increased, or macro-porosity decreased, as a result of soil compaction, CH 4 emissions increased (Table 4). ...
Article
The furrow-irrigated rice (Oryza sativa) production system has been developed as an alternative water conservation practices, but results in spatially variable soil conditions. No research has been conducted to relate greenhouse gas (GHG) production to soil and plant properties or environmental factors under furrow-irrigated rice in the mid-southern, USA. The objective of this field study was to evaluate relationships between methane (CH4), nitrous oxide (N2O), and carbon dioxide (CO2) fluxes and emissions and global warming potential (GWP) and early season soil properties and environmental factors over two growing seasons (2018 and 2019) under furrow-irrigated rice on a silt-loam soil (Typic Albaqualf). Gas samples were collected weekly between planting and harvest from enclosed-headspace, static chambers and analyzed by gas chromatography. Methane fluxes were correlated with soil moisture (r = 0.18) and oxidation-reduction (redox) potential (r = −0.59), N2O fluxes were correlated with redox potential (r = 0.13), and CO2 fluxes were correlated with soil moisture (r = 0.29), redox potential (r = −0.27), and temperature (r = 0.09). Results suggested that environmental parameters like soil temperature, soil moisture, and redox potential can be included in management practices as controlling factors for production and release of GHG fluxes. Methane, and N2O, emissions were positively (0.36 < r < 0.78) and negatively (−0.33 < r < −0.54) correlated with numerous soil and plant properties. Significant multiple regression models predicting season-long CH4-C, N2ON, CO2-C, and GWP from a suite of soil and plant properties were identified (0.49 < R² < 0.78). Results demonstrated that numerous soil, plant, and environmental factors substantially control GHG production and release.
... Probably, drying the field can reduce toxicity of organic and inorganic toxins that accumulate from the decomposition of organic materials at the beginning of cropping season (Kongchum, 2005). Short aeration periods at the end of the tillering stage and just before flowering improve wetland rice yields only if followed by flooding (Neue, 1993). The growing scarcity and competition for water is occurring worldwide. ...
Article
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More than 75% of the rice produced comes from irrigated land. However, the water crisis threatens the sustainability of the irrigated system. The supply of water for irrigation is endangered by declining water quality, declining resource availability, increased competition from other users, and increasing costs. Rice is especially sensitive to declining water availability since it requires more water than any other food crop and it has relatively low water-use efficiency. Through the adoption of water-saving irrigation technologies, rice land will shift away from being continuously anaerobic to being partly or even completely aerobic. This will have major consequences for other aspects of sustainability, such as weed, pest, and disease ecology and nutrient and soil organic matter dynamics.
... A similar range of strategies can be envisaged for crop production. For rice, Neue (1993) identifies a range of strategies for reducing emission intensities. Millar et al (2014) identify a similar range of strategies for reducing N2O emissions from other cereal crops, using approaches such as selecting the right application rate, using the right fertilizer formulation, and optimizing the timing and placement of fertilizers. ...
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To understand the impacts of support programs on global emissions, this paper considers the impacts of domestic subsidies, price distortions at the border, and investments in emission-reducing technologies on global greenhouse gas (GHG) emissions from agriculture. In a step towards a full evaluation of the impacts, it uses a counterfactual global model scenario showing how much emissions from agricultural production would change if agricultural support were abolished worldwide. The analysis indicates that, without subsidies paid directly to farmers, output of some emission-intensive activities and agricultural emissions would be smaller. Without agricultural trade protection, however, emissions would be higher. This is partly because protection reduces global demand more than it increases global agricultural supply, and partly because some countries that currently tax agriculture have high emission intensities. Policies that directly reduce emission intensities yield much larger reductions in emissions than those that reduce emission intensities by increasing overall productivity because overall productivity growth creates a rebound effect by reducing product prices and expanding output. A key challenge is designing policy reforms that effectively reduce emissions without jeopardizing other key goals such as improving nutrition and reducing poverty. While the scenario analysis in this paper does not propose any particular policy reform, it does provide an important building block towards a full understanding the impacts of repurposed agricultural support measures on mitigation of greenhouse gas emissions and adaptation to climate change. That full analysis is being undertaken in subsequent work, which will also take account of land-use change and alternative forms of agricultural policy support to align objectives of food security, farmers’ income security, production efficiency and resilience, and environmental protection.
... A similar range of strategies can be envisaged for crop production. For rice, Neue (1993) identifies a range of strategies for reducing emission intensities. Millar et al (2014) identify a similar range of strategies for reducing N2O emissions from other cereal crops, using approaches such as selecting the right application rate, using the right fertilizer formulation, and optimizing the timing and placement of fertilizers. ...
... Probably, drying the field can reduce toxicity of organic and inorganic toxins that accumulate from the decomposition of organic materials at the beginning of cropping season (Kongchum, 2005). Short aeration periods at the end of the tillering stage and just before flowering improve wetland rice yields only if followed by flooding (Neue, 1993). The growing scarcity and competition for water is occurring worldwide. ...
Research
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More than 75% of the rice produced comes from irrigated land. However, the water crisis threatens the sustainability of the irrigated system. The supply of water for irrigation is endangered by declining water quality, declining resource availability, increased competition from other users, and increasing costs. Rice is especially sensitive to declining water availability since it requires more water than any other food crop and it has relatively low water-use efficiency. Through the adoption of water-saving irrigation technologies, rice land will shift away from being continuously anaerobic to being partly or even completely aerobic. This will have major consequences for other aspects of sustainability, such as weed, pest, and disease ecology and nutrient and soil organic matter dynamics.
... A similar range of strategies can be envisaged for crop production. For rice, Neue (1993) identifies a range of strategies for reducing emission intensities. Millar et al (2014) identify a similar range of strategies for reducing N 2O emissions from other cereal crops, using approaches such as selecting the right application rate, using the right fertilizer formulation, and optimizing the timing and placement of fertilizers. ...
... Meskipun konsentrasi CH4 yang terdapat di atmosfer lebih kecil dibandingkan konsentrasi CO2 tetapi CH4 dapat menyerap panas 21 kali lebih besar dibandingkan dengan CO2 (IPPC 1990diacu dalam Lilivevel et al 1992. Emisi CH4 yang dihasilkan oleh tanah cukup besar yaitu sebesar 60% dan sektor pertanian diduga menjadi penyumbang penting emisi gas rumah kaca (Neue 1993;Hadi 2001;Setyanto dan Abubakar 2005). Saat ini sistem pertanian yang umum digunakan oleh masyarakat adalah sistem pertanian konvensional, dimana sistem pertanian tersebut menghasilkan emisi gas rumah kaca yang cukup tinggi. ...
... Ekosistem dengan kondisi anaerob yang dominan, terutama akibat penggenangan (contohnya sawah), merupakan sumber utama emisi gas CH 4 (Rudd dan Taylor 1980). Oleh karena itu, pertanian sawah sebagai faktor antropogenik berperan penting dalam proses produksi gas CH 4 (Li et al. 2005;Neue 1993). ...
... Reduction of the rates of rhizodeposition, therefore, is beneficial to both yield and reduced CH 4 emissions [70]. Rice straw (RS) composted properly resulted in a six-fold reduction in CH 4 emission compared with partially composted RS [71]. Dual cropping of Azolla in conjunction with urea considerably reduced CH 4 efflux without affecting the rice yields and can be used as a practical adaptation option for minimizing CH 4 flux from flooded paddy [72]. ...
... Methane is exclusively produced by methanogenic bacteria that can metabolize only in the strict absence of free oxygen and at redox potentials of less than À150 mV. In wetland rice soils, methane is largely produced by transmethylation of acetic acid and, to some extent, by the reduction of carbon dioxide (Neue, 1993). CH 4 emission was very low in the control treatment likely from inhibition of microbes due to lack of nutrients and suitable reducing substrates; however, CH 4 emissions were significantly greater in the plots treated with chemical fertilizer and ADS, presumably because sufficient nutrients and reducing substrates for methane-producing microorganism were present. ...
Article
One hundred million tons of farm stalk waste and livestock and poultry excrement are used every year in China for the production of clean energy (biogas) by anaerobic digestion. Consequently, a large amount of fermented liquid is produced, and if disposed of improperly, it will result in secondary pollution. Agricultural application of this anaerobic slurry as a liquid fertilizer would reduce possible eutrophication of water sources from random slurry discharge and supply a superior organic fertilizer for farming. This study investigated the effect of applying anaerobic digestion slurry as a liquid fertilizer on the methane emitted from a paddy field. A two-year (2008–2009) field experiment replacing chemical fertilizer with liquid fertilizer from anaerobically digested pig manure slurry was conducted in a paddy field in Yixing, Jiangsu, China. A static closed chamber method was used to measure methane fluxes over the period from June 2008 to October 2009. All fertilizer treatments increased methane emissions relative to untreated controls, with increases in methane ranging from 40–70% in 2008 to 48–84% in 2009. Paddy fields treated with anaerobically digested pig manure slurry had greater methane emissions (8–84% in 2008 and 3–26% in 2009) than those treated with chemical fertilizer. This suggests that the anaerobic digestion slurry would increase methane emission and so is unsuitable as a liquid fertilizer in paddy fields without development of cultivation practices to limit these emissions.
... Pada kondisi tergenang, kebutuhan oksigen yang tinggi dibandingkan laju penyediannya yang rendah menyebabkan terbentuknya dua lapisan tanah yang sangat berbeda, yaitu lapisan permukaan yang oksidatif atau aerobik dimana tersedia oksigen dan lapisan reduktif atau enaerobik di bawahnya dimana tidak tersedia oksigen bebas (Patrick and Reddy, 1978). Metan diproduksi sebagai hasil akhir dari proses mikrobial melalui proses dekomposisi bahan organik secara anaerobik oleh bakteri metanogen (Neue, 1993). Bakteri ini hanya aktif bila kondisi tanah dalam keadaan tergenang. ...
Article
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Sistem irigasi berselang dan jarak tanam legowo 2:1 diduga dapat meningkatkan produktivitas padi dan menurunkan emisi Gas Rumah Kaca (GRK). Penelitian bertujuan mengetahui pengaruh sistem irigasi berselang dan jarak tanam legowo 2:1 terhadap produktivitas padi dan emisi GRK gas CH4 (metan). Penelitian menggunakan rancangan petak terpisah dengan tiga ulangan. Petak utama adalah sistem irigasi berselang (I) meliput: I1 = Irigasi berselang 3 hari digenangi; 3 hari dikeringkan (3:3); I2 = Irigasi berselang 5 hari digenangi; 3 hari dikeringkan (5:3); I3 = Irigasi berselang 7 hari digenangi; 3 hari dikeringkan (7:3). Anak petak adalah jarak tanam legowo 2:1 terdiri atas: L1 = Legowo 2:1 (25 x 15 x 50 cm); L2 = Legowo 2:1 (25 x 12,5 x 50 cm); L3 = Legowo 2:1 (25 x 15 x 40 cm); dan L4 = Legowo 2:1 (25 x 12,5 x 40 cm). Pengumpulan data meliputi: emisi gas CH4; pertumbuhan tanaman; bobot 1.000 butir; hasil padi. Data dianalisis dengan Analysis of Varians, uji nilai tengah Duncan. Hasil penelitian menunjukkan tidak terjadi interaksi antara irigasi berselang dengan jarak tanam legowo 2:1 terhadap emisi gas metan. Irigasi berselang 5 hari digenangi; 3 hari dikeringkan (5:3) dapat menurunkan emisi gas metan dan meningkatkan produktivitas padi 17,2% dari 5,88 menjadi 6,89 t/ha. Jarak tanam legowo 2:1 yang dapat menurunkan emisi gas metan adalah 25 x 15 x 40 Cm, sedangkan yang dapat meningkatkan produktivitas padi adalah 25 x 12,5 x 40 cm, yaitu sebesar 13,6% dari 6,04 menjadi 6,86 t/ha Gabah Kering Giling (GKG).
... The increased residue incorporation under CT of soils facilitates supply of substrate to methanogens and also stimulates the organisms to grow luxuriantly. Neue (1993) and Minamikawa et al. (2006) also reported that the application of carbon-rich straw helps methanogens survive and lowers redox potential in soils. ...
Article
Emerging conservation agriculture (CA) technologies are being applied in rice-upland cropping systems and their potential to mitigate greenhouse gas emissions of the whole rice-based cropping systems could be significant in South Asia especially if they increase soil organic carbon (SOC) stocks. A streamlined life cycle assessment was conducted in the Eastern Gangetic Plains (Bangladesh) to determine greenhouse gas emissions from successive crops of monsoon rice (Oryza sativa), mustard (Brassica juncea) and irrigated rice under CA practices in contrast with the conventional crop establishment practice while accounting for changes in SOC. The life cycle greenhouse gas tonne ⁻¹ rice equivalent yield was assessed for four cropping practices: a) traditional crop establishment practices with farmers’ practice of minimal residue return, or b) CT with return of increased residues; c) strip planting (for mustard)/transplanting on non-puddled soils (for rice) with farmers’ practice of minimal residue return or; d) strip planting/non-puddled transplanting with increased residue return. The global warming potential values for the 100-year timescale were used to calculate CO 2 eq emissions within the system boundary. The net life cycle greenhouse gas emissions after allowing for changes in SOC sequestration varied from 0.73 to 1.12 tonne CO 2 eq tonne ⁻¹ rice equivalent yield. In the annual cropping system, methane (CH 4 ) released from on-farm stage of the life cycle assessment, particularly from the rice crops, represented the dominant contributor to life cycle greenhouse gas emissions. The greenhouse gas emitted by machinery usage during the on-farm stage (irrigated rice), CO 2 emission from soil respiration (monsoon rice), and greenhouse gas related to manufacture of inputs (mustard) were secondary sources of emission, in that order of priority. The non-puddlled transplanting of soil with low and increased residue retention were the most effective greenhouse gas mitigation options when sequestered SOC was taken into account (they avoided 35% of the net life cycle footprints compared with current farmers’ practice) in footprints of component crops of the rice-upland cropping system. The CA approaches being developed for the Eastern Gangetic Plains involving strip planting or non-puddled transplanting of rice have potential to mitigate global warming potential of intensive rice-based triple cropping systems but the life cycle assessment approach needs to be applied to a more diverse range of rice-based cropping systems.
... The direct impact of chemical fertilizer applications on methane emission is not clear. Because most methane is emitted through the rice plant, improved rice growth (more tiller and roots) in response to fertilizer application increases emission (Neue 1993). Improved methods of fertilizer application, matching with crop requirement to reduce nitrous oxide in uplands and methane emission in lowlands is one of the transformation and mitigation strategies towards climate resilience agriculture. ...
... 8 (1): 26-37, June, 2018 is going to be the rigorous problems for securing world rice production (Nguyen, 2007). Moreover, Neue (1993) based on a series of experiments additionally revealed from wetland rice culture, methane was released to biosphere and this had a major detrimental effect to global warming. Methane proportion is around 15%, while CO2 is around 55% into the total of greenhouse gases, but due to methane can absorb heat latently, so methane emission is more dangerous, and consequently it should be reduced. ...
Article
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p>Green revolution started at mid of twentieth century was the answer of anxiousness reminded by Malthusian that food scarcity problems in relation with population growth. In concurrence with exploitation of fossil fuel for agriculture mechanization as well as agrochemicals in the form of inorganic fertilizer and pesticide, green revolution by introducing high yielding varieties of cereals and grains was able to nourish the world population by increasing productivity. Indeed, from beginning of mechanization with fossil fuel based as advised by Rudolf Diesel then Arrhenius would be affected to the release of CO2 to the atmosphere and consequently exaggerating climate change as suffered by current and future generations. Under green revolution based on cereals and grains affected forest conversion into open agricultural land, because both commodities are sun-loving crops, which are hate to the shade. On the other hand, to slow the severity of climate change natural forest must be conserved tightly. Entering third millennium demand of food production with ecologically friendly is stronger. Hence, green revolution needs to be amended into greener perspectives. Thus, implementation of agro-forestry into wide range of agro-ecological zone is urgently innovated. Fortunately, shade tolerant of root crops has significant advantage to be developed under agro-forestry. Under shade of forest canopy at basal forest strata, root crops are able to sequester CO<sub>2</sub> to be converted into carbohydrate and other compounds to provide food for the dweller. Back to nature is not only a slogan, with root crops under agro-forestry is a reality; fresh root up to 30 t ha-1 can be harvested yearly as the source of food and renewable fuel as well. This potential is very worthy to improve and greening the existing green revolution to be more sustainable. Int. J. Agril. Res. Innov. & Tech. 8 (1): 26-37, June, 2018</p
... Rice cultivation plays a major role in global warming by green house gas emissions (Neue, H. 1993;Sass and Cicerone 2002;Jain et al., 2004;Linquist et al., 2012;Gaihre et al., 2013;Pittelkow et al., 2013). Matthews et al., 1991, identified that 55% of the annual methane emission over rice growing areas is concentrated into four months, from July to October i.e. the predominant rice cultivation season. ...
Article
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Climate change and its effects on agriculture will impact global food security. Rice (Oryza sativa L.), the major staple crop of the world, is subjected to substantial environmental constraints and criticism because of its role in climate change; methane emission under irrigated ecosystem. Mitigation of methane is the way forward for sustainable and eco-friendly rice production. Limiting area and production of rice may not be a feasible option as majority of the Asian population depends on rice. An urgent and integrated research approach to understand the mechanisms and interactions involved in methane release through rice plant is required to design viable mitigation technologies. Genetics of methane emission must be studied in detail, along with agronomic and management practices to obtain the precise information to elucidate the inheritance of related traits. Crop improvement interventions are required to identify contributing traits to methane emission, with subsequent deployment in plant breeding. Identification of rice cultivars with high-yield levels and traits contributing to low methane production represents an economic approach. Focus of breeding needs a shift towards adaptation to new production systems that can sustain effects of climate change. Low methane emitting varieties suitable to water management practices are more promising. This can be manifested in simultaneous achievement of global food security and mitigation of emissions without radical changes in the agronomic practices for the rice ecosystem. In this Review, an account of methane emission studies from rice and impact of crop growth stages as well as traits are outlined. The genotypic variation reported in Oryza spp for methane emission and breeding approaches for development of low methane emitting varieties are discussed.
... Furthermore, Nguyen [6] also pointed out that slash and burn for cultivating upland rice, inducing or even triggering deforestation, will contribute to global warming due to the decrease of sink capacity to absorb CO 2 . Moreover, Neue [7] based on a series of experiments additionally revealed from wetland rice culture, that methane was released to the biosphere and this also had a major detrimental effect to global warming. The methane proportion of total greenhouse gases is around 15%, while CO 2 is around 55%, but since methane can absorb heat latently, so methane emission is more dangerous, and consequently it should be reduced. ...
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Entering the third millennium food and energy crisis is becoming more serious in line with water scarcity amid of climate change induced by global warming, that so called as FEWS (food energy and water scarcity). In the last five decades Indonesian agricultural development of food crops had been emphasized on cereals and grains based. Conversion of forest into agricultural field in the form of upland and lowland facilitated by irrigation is prioritized for cereals such as rice, maize as well as grain legumes such as soybean, peanut etc. Unfortunately, root crops which their main yield underground are neglected. At the end of second millennium Indonesia was seriously suffered from multi-crisis economic trap, so Indonesia as part of countries under World Food Program to import the huge of food to cover domestic consumption such as rice, wheat, soybean, corn etc. On the other hand, consumption of energy was also increase significantly. These conditions triggering government to stimulate integrated agricultural enterprises for providing abundance of food as well as adequate renewable energy. Although root crops were neglected previously, however from its biological potential to produce biomass promotes root crops into an appropriate position. The variability of root crops which ecologically can be grown from upland in dry areas till swampy submergence condition. Forest conversion into agricultural land is not allowed due to forest is useful to prevent global warming. Therefore, food, feed and fuel (renewable energy) production have to be able grown under agro-forestry. Fortunately the potential of root crops has competency to meet the current need to fulfil food, feed and fuel as well as fibre under future greener environment.
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The Northern Song period (960–1127) has been recognized as one of the most important eras in China's economic and demographic history. This study investigates the key factors and mechanisms that led to economic restructuring and wealth generating to support a growing population. By revealing state-led changes in the economy, it challenges some commonly circulated interpretations of the remarkable economic development and population growth in Northern Song China.
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We report measurements of CH4 flux and δ13C and δD values of emitted CH4 and sediment CH4 and CO2 during the 1995 rice growing season in Beaumont, Texas. Four rice plant cultivars, Lemont, Mars, Cypress, and Della, and an unplanted plot were studied to provide possible explanations for the differences in CH4 emissions between cultivars. Using the measured isotope values, along with data of CH4 and CO2 concentrations and other ecosystem data, we determined differences between cultivars in the processes of oxidation and production throughout the growing season. For instance, rhizospheric CH4 oxidation increased as the season progressed in both Mars and Lemont cultivars. Late in the season, however, 71+/-10% of CH4 produced in the Mars plot was oxidized compared to only 39+/-10% in the Lemont plot. The contribution of acetate fermentation to methanogenesis at specific times during the season was calculated using measured isotopic values and assuming identical isotopic fractionation factors in methanogenic pathways for the cultivars. In these calculations a range of values for the contribution to CH4 production from acetate fermentation and CO2 reduction with H2 was estimated by considering different fractionation factors for the methanogenic CO2 reduction pathway and the possibility of a 10% contribution to CH4 production from acetate produced by homoacetogenesis. In general, a steady increase in the CH4 portion produced by acetate fermentation was noted in the Lemont cultivar, while an increase followed by a decrease near the end of the season was observed for the Mars cultivar.
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