Behaviour of Iodine-129 in Rice Paddy Fields

1994 ◽  
Vol 353 ◽  
Author(s):  
Shigeo Uchida ◽  
Yasuyuki Muramatsu
Keyword(s):  
Soil Solution ◽  
Root Zone ◽  
Brown Rice ◽  
Iodine Concentration ◽  
Rice Paddy ◽  
Paddy Fields ◽  
Transfer Factors ◽  
Rice Plants ◽  
Continuous Deposition ◽  
Gray Lowland Soil

AbstractTransfer factors of iodine from soil to rice were obtained by laboratory experiments using 125I tracer. Two typical soil types in Japan, Andosol and Gray lowland soil, were used. The transfer factor (TF) is defined as ’concentration of the nuclide in a plant organ at harvest’ divided by ’concentration of the nuclide in dry soil’. The TFs for brown (hulled) rice were 0.006 for Andosol and 0.002 for Gray lowland soil. The TFs for different organs of rice plants decreased in the order of blade > stem > rachis > unhulled rice >> brown rice.The concentration of iodine in soil solution under flooded conditions varied with time during cultivation. The iodine concentration in rice plants seemed to be influenced by the soil solution.The effect of removal of 1–129 from paddy fields by harvesting rice plants was also modelled. Even assuming continuous deposition of 1–129 onto the field, annual harvesting of the blades and stems of rice plants could effectively reduce the amount of the nuclide in the root zone.

scholarly journals Rice plants reduce methane emissions in high-emitting paddies

F1000Research ◽  
2019 ◽  
Vol 7 ◽  
pp. 1349 ◽  
Author(s):  
Masato Oda ◽  
Nguyen Huu Chiem
Keyword(s):  
Organic Matter ◽  
Soil Organic Matter ◽  
Methane Emission ◽  
Rice Variety ◽  
Mekong Delta ◽  
Rice Paddy ◽  
Methane Emissions ◽  
Paddy Fields ◽  
Rice Plants ◽  
Oxygen Pathways

Background: Rice is understood to enhance methane emissions from paddy fields in IPCC guidelines. However, rice actually has two opposite functions related to methane: i) emission enhancement, such as by providing emission pathways (aerenchyma) and methanogenetic substrates; and ii) emission suppression by providing oxygen pathways, which suppress methanogenesis or enhance methane oxidation. The overall role of rice is thus determined by the balance between its enhancing and suppressing functions. Although previous studies have suggested that rice enhances total methane emissions, we aimed to demonstrate in high-emitting paddy fields that the overall methane emission is decreased by rice plants. Methods: We compared methane emissions with and without rice plants in triple cropping rice paddy fields in the Mekong Delta, Vietnam. The gas samples are collected using chamber method and ware analyzed by gas chromatography. Results: We found that rice, in fact, suppressed overall methane emissions in high-emitting paddies. The emission reductions increased with the growth of rice to the maximum tillering stage, then decreased after the heading stage, and finally recovered.  Discussion:  Our result indicates that the overall methane emission is larger than that of rice planted area. In addition, although many studies in standard-emitting paddies have found that the contribution of soil organic matter to methanogenesis is small, prior studies in high-emitting paddies suggest that methanogenesis depended mainly on soil organic matter accumulated from past crops. The higher the methane emission level, the lower the contribution of the rice-derived substrate; conversely, the higher the contribution of the rice providing oxygen. Finally, rice plants reduce methane emissions in high-emitting paddies. Conclusion: The present study demonstrates that during the growing season, rice is suppressing methane emissions in high-emitting paddies. This means the significance of using the rice variety which has high suppressing performance in high-emitting paddies.

scholarly journals Micro-Water Harvesting and Soil Amendment Increase Grain Yields of Barley on a Heavy-Textured Alkaline Sodic Soil in a Rainfed Mediterranean Environment

Agronomy ◽  
2021 ◽  
Vol 11 (4) ◽  
pp. 713
Author(s):  
Edward G. Barrett-Lennard ◽  
Rushna Munir ◽  
Dana Mulvany ◽  
Laine Williamson ◽  
Glen Riethmuller ◽  
...  
Keyword(s):  
Soil Solution ◽  
Elemental Sulfur ◽  
Root Zone ◽  
Soil Surface ◽  
Conventional Tillage ◽  
Barley Grain ◽  
Control Treatment ◽  
Water Harvesting ◽  
Hordeum Vulgare L ◽  
Salt Leaching

This paper focuses on the adverse effects of soil sodicity and alkalinity on the growth of barley (Hordeum vulgare L.) in a rainfed environment in south-western Australia. These conditions cause the accumulation of salt (called ‘transient salinity’) in the root zone, which decreases the solute potential of the soil solution, particularly at the end of the growing season as the soil dries. We hypothesized that two approaches could help overcome this stress: (a) improved micro-water harvesting at the soil surface, which would help maintain soil hydration, decreasing the salinity of the soil solution, and (b) soil amelioration using small amounts of gypsum, elemental sulfur or gypsum plus elemental sulfur, which would ensure greater salt leaching. In our experiments, improved micro-water harvesting was achieved using a tillage technique consisting of exaggerated mounds between furrows and the covering of these mounds with plastic sheeting. The combination of the mounds and the application of a low rate of gypsum in the furrow (50 kg ha−1) increased yields of barley grain by 70% in 2019 and by 57% in 2020, relative to a control treatment with conventional tillage, no plastic sheeting and no amendment. These increases in yield were related to changes in ion concentrations in the soil and to changes in apparent electrical conductivity measured with the EM38.

scholarly journals Effects of Biochar Amendment on CO2 Emissions from Paddy Fields under Water-Saving Irrigation

2018 ◽  
Vol 15 (11) ◽  
pp. 2580 ◽  
Author(s):  
Shihong Yang ◽  
Zewei Jiang ◽  
Xiao Sun ◽  
Jie Ding ◽  
Junzeng Xu
Keyword(s):  
Co2 Emissions ◽  
Rice Yield ◽  
Rice Paddy ◽  
C Sequestration ◽  
Sensitivity Coefficient ◽  
Water Saving ◽  
Paddy Fields ◽  
Flood Irrigation ◽  
Controlled Irrigation ◽  
Biochar Amendment

The role of carbon pool of biochar as a method of long-term C sequestration in global warming mitigation is unclear. A two-year field study was conducted to investigate the seasonal variations of CO2 emissions from water-saving irrigation paddy fields in response to biochar amendment and irrigation patterns. Three biochar treatments under water-saving irrigation and one biochar treatment under flooding irrigation were studied, and the application rates were 0, 20, 40, and 40 t ha−1 and labeled as CI + NB (controlled irrigation and none biochar added), CI + MB (controlled irrigation and medium biochar added), CI + HB (controlled irrigation and high biochar added), and FI + HB (flood irrigation and high biochar added), respectively. Results showed that biochar application at medium rates (20 t ha−1) decreased CO2 emissions by 1.64–8.83% in rice paddy fields under water-saving irrigation, compared with the non-amendment treatment. However, the CO2 emissions from paddy fields increased by 4.39–5.43% in the CI + HB treatment, compared with CI + NB. Furthermore, the mean CO2 emissions from paddy fields under water-saving irrigation decreased by 2.22% compared with flood irrigation under the same amount of biochar application (40 t ha−1). Biochar amendment increased rice yield and water use efficiency by 9.35–36.30% and 15.1–42.5%, respectively, when combined with water-saving irrigation. The CO2 emissions were reduced in the CI + MB treatment, which then increased rice yield. The CO2 emissions from paddy fields were positively correlated with temperature. The highest value of the temperature sensitivity coefficient (Q10) was derived for the CI + MB treatment. The Q10 was higher under water-saving irrigation compared with flooding irrigation.

scholarly journals Dry matter accumulation and plant type of the high yielding soybean grown under converted rice paddy fields.

1984 ◽  
Vol 53 (4) ◽  
pp. 510-518 ◽  
Author(s):  
Kimio NAKASEKO ◽  
Humio NOMURA ◽  
Kanji GOTOH ◽  
Takeshi OHNUMA ◽  
Yoshikatsu ABE ◽  
...  
Keyword(s):  
Dry Matter ◽  
Rice Paddy ◽  
Paddy Fields ◽  
Dry Matter Accumulation ◽  
Plant Type ◽  
Rice Paddy Fields

scholarly journals Draft Genome Sequences of Two Gammaproteobacterial Methanotrophs Isolated from Rice Ecosystems

2017 ◽  
Vol 5 (33) ◽  
Author(s):  
Katharina Frindte ◽  
Marina G. Kalyuzhnaya ◽  
Françoise Bringel ◽  
Peter F. Dunfield ◽  
Mike S. M. Jetten ◽  
...  
Keyword(s):  
Draft Genome ◽  
Rice Paddy ◽  
Genome Sequences ◽  
Content Type ◽  
Rice Plants ◽  
Rice Ecosystems ◽  
Aerobic Methanotrophs

ABSTRACT The genomes of the aerobic methanotrophs “Methyloterricola oryzae” strain 73aT and Methylomagnum ishizawai strain 175 were sequenced. Both strains were isolated from rice plants. Methyloterricola oryzae strain 73aT represents the first isolate of rice paddy cluster I, and strain 175 is the second representative of the recently described genus Methylomagnum.

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