상승온도 처리에 의한 논과 밭 용수의 질소변화

홍성창 ( Hong Sung-chang ),장은숙 ( Jang Eun-suk ),허승오 ( Hur Seung-oh ),최순군 ( Chio Soon-kun ),유선영 ( Yu Sun-young ),이규현 ( Lee Gyu-hyen ),김경식 ( Kim Kyeong-sik ) 한국환경농학회 2019 한국환경농학회 학술대회집 Vol.2019 No.-

Temperature increases due to climate change are affecting various sectors of agriculture. Elevated temperatures can affect the growth and yield of crops and can also affect the utilization efficiency of nutrient input materials such as soil nutrients, chemical fertilizers, and compost. The outflow of non-point pollutant sources from farmlands is strongly influenced by physical factors such as rainfall, rainfall intensity, and slope of agricultural land. In order to simulate the outflow of non-point pollutant sources due to climate change, it is necessary to find out not only the physical factors but also the changes in the biological factors induced by the elevated temperature in detail. Temperature is one of the most important environmental factors controlling the growth and yield of plants, and the rate of reaction depends on temperature in all biological processes. Elevated temperatures increase nitrogen mineralization and net nitrification rate. The degradation, absorption, utilization, and outflow of the variety of nutrient input materials for crop cultivation can differ due to temperature rise. This study was carried out to investigate the changes of nitrogen in the nutrients of the cultivated waters by cultivating rice and maize in pots after simulating climate change and by establishing an elevated temperature environment with the chemical fertilizer and livestock compost. The elevated temperature environment was established using the modified medium open-top chamber whose width is 6m and height is 3m. The medium open-top chamber has a merit of increasing only temperature while maintaining the environmental factors such as rainfall, wind, and sunlight intensity similar as those in the field. The maximum temperature in the open-top chamber measured on the 15th of May, 2018 was higher by 2.7℃ than the field, while the average temperature was higher by 0.4℃ so that the elevated temperature could be applied to the rice and maize throughout the growth period. The rice and maize were planted in Wagner pots filled with sandy loam and clay loam, and then placed in a medium open-top chamber and grown at elevated temperatures. The analysis results of nitrogen by periodically collecting the cultivation water from the Wagner pots during the cultivation period of the rice and maize showed that the NO₃―N concentration in the paddy cultivation water was decreased in the no-fertilization block, chemical fertilizer treated block, and cow dung compost treated block in the paddy cultivation sandy loam under elevated temperature compared to those in the field. Meanwhile, the NH₄― N concentration was increased in the rice cultivation clay loam soil in all the treated blocks compared to the field. The NO₃―N concentration in the cultivated water was decreased in all the treatment blocks in the maize cultivation clay loam soil by the elevated temperature than that of field. However, NH₄―N concentration in the water from the maize cultivation sandy loam soil, as well as the clay loam soil with the chemical fertilizer, was increased by elevated temperature compared to the field. The results indicate that the nitrogen changes in the water of the paddy field and upland are induced under the elevated temperature. The outflow of the non-point pollutant sources towards the water system near the cultivation fields also can be changed by rainfall.

온도상승 환경 처리가 논토양과 용수에서 탄소량 변화와 벼 생육에 미치는 영향

홍성창 ( Sung-chang Hong ),허승오 ( Seung-oh Hur ),최순군 ( Soon-kun Choi ),최동호 ( Dong-ho Choi ),장은숙 ( Eun-suk Jang ),( Climate Change ) 한국환경농학회 2018 한국환경농학회지 Vol.37 No.1

상승온도 처리에 따른 논토양 탄소의 변동과 벼 생육을 조사한 결과를 요약하면 다음과 같다. 소형 상부개방형 챔버를 이용하여 대기온도 보다 0.4℃, 0.5℃, 0.9℃ 상승온도 환경을 조성하여 상승온도를 처리할 수 있었다. 사각챔버의 내부온도는 대기보다 평균온도와 최고온도가 높고 최저온도는 낮은 특징을 나타내었다. 상승온도 처리구의 포트 내 표면수의 TOC 농도는 대조구 보다 상승온도 처리구에서 높았고 시간이 경과함에 따라 점차 낮아졌다. 벼 재배후 토양의 TOC함량은 대조구 보다 상승온도 처리구에서 낮았다. 상승온도 처리로 벼 식물체의 탄소함량은 감소하고 질소함량은 증가하여 C/N 율은 감소하는 경향을 나타내었다. 상승온도 처리로 대조구 보다 벼의 줄기 길이와 줄기무게가 유의하게 증가하였으나 이삭수와 벼 낱알 무게는 유의한 차이를 나타내지 않았다. BACKGROUND: The global mean surface temperature change for the period of 2016∼2035 relative to 1986~2005 is similar for the four representative concentration pathway (RCP)’s and will likely be in the range of 0.3℃ to 0.7℃. Climate change inducing higher temperature could affect not only crop growth and yield, but also dynamics of carbon in paddy field. METHODS AND RESULTS: This study was conducted to evaluate the effect of elevated temperature on the carbon dynamics in paddy soil and rice growth. In order to control the elevated temperatures, the experiments were set up as the small scale rectangular open top chambers (OTCs) of 1 m (width)×1 m (depth)×1 m (height) (Type 1), 1 m (W)×1 m (D)×1.2 m (H) (Type 2), and 1 m (W)×1 m (D)×1.4 m (H) (Type 3). The average temperatures of Type 1, Type 2, and Type 3 from July 15 to October 30 were higher than the ambient temperatures at 0.4℃, 0.5℃, and 0.9℃, respectively. For the experiment, Wagner’s pots (1/2,000 area) were placed inside chambers. The pots were filled with loamy soil, and chemical fertilizer and organic compost were applied as recommended after soil test. The pots were flooded with agricultural water and rice (Shindongjin-byeo) was planted. It was observed that TOC (total organic carbon) of the water increased by the elevated temperatures and the trend continued until the late growth stage of the rice. Soil TOC contents were reduced by the elevated temperatures. C/N ratios of the rice plant decreased by the elevated temperature treatments. Thus, it was assumed that the elevated temperatures induced to decompose soil organic matter. Elevated temperatures significantly increased the culm length (P<0.01) and culm weight (P<0.05) of rice, but the number and weight of rice panicle did not showed significant differences. CONCLUSION: Based on the results, it was suggested that the elevated temperatures had an effect on changes of soil and water carbons under the possible future climate change environment.

$CO_2$ 농도의 상승과 온난화환경이 수도의 생장, 물질생산 및 그 분배에 미치는 영향

김한용 한국자원식물학회 1998 한국자원식물학회지 Vol.11 No.1

The influence of elevated CO2 and temperature on growth parameters, biomass production and its partitioning of rice (Oryza sativa L.cv. Chukwangbyeo) were investigated in the three experiments (1991-1993). Rice plants were grown from transplanting to harvest at either ambient(350ppm) or elevated CO2 concentrations (690 or 650ppm) in combination with either four or seven temperature regimes ranging form ambient temperature (AT) to AT plus 3$^{\circ}C$.From transplanting to panicle initiation, crop growth rate (CGR) was enhanced by up to 27% with elevated CO2 , primarily due to an an increase in leaf area index. although net assimilatiion rate was also greater at elevated CO2. The effect of elevated CO2 varied with temperature. During the reproductive phase, CGR declined linearly with increased temperature, and was greater at elevated CO2 . Elevated CO2 increased final crop biomass and panicle weight 30% respectively at AT(27.6$^{\circ}C$ : 1991) . However, there was no significant effect of elevated CO2 on panicle weight at AT plus 3$^{\circ}C$, where severe spikelet sterility occurred. There was no significant effect of elevated CO2 on panicle weight at AT plus 3$^{\circ}C$, where severe spikelet sterility occurred. There was also no effect of CO2 on biomass pratitioning into vegetative and reproductive organs (harvest index)) at AT, although higher temperature could affect that by inducing spikelet sterility. These results suggest that elevated CO2 could enhance rice producivity througth promoted growth and biomass production , but its positive effects may be less at higher temperatures.

Temperature-Dependent Adsorption of U(VI) Onto γ-Alumina

Herath Mudiyanselage Samadhi Kaushalye Herath,Jong-Il Yun 한국방사성폐기물학회 2022 한국방사성폐기물학회 학술논문요약집 Vol.20 No.1

An elevated temperature is expected at the deep geological repository (DGR) due to the decay heat from spent nuclear fuel and the positive geothermal gradient. The resulting elevated temperature would change the aqueous speciation and surface complexation of uranium, which is the major component in spent nuclear fuel. Since sorption reactions of uranium species on natural minerals determine the extent of uranium retardation, in this work the temperature-dependent adsorption of hexavalent uranium, U(VI), was studied by choosing alumina as the basic component mineral for complex aluminosilicates. Time-resolved laser fluorescence spectroscopy (TRLFS) was used to assess the dissolved and adsorbed U(VI) species on γ-Alumina in the pH range of 6.5–9.0 at temperatures of 25 to 70°C. Initial concentrations of U(VI), carbonate and calcium were 89 μM, 25 mM, and 3.0 mM, respectively. The parallel factor analysis (PARAFAC) was used for chemical speciation by spectrum deconvolution. In addition, a separate solution system with higher U(VI) concentrations (0.1 mM, 1.0 mM) and carbonate concentration of 25 mM was studied with attenuated total reflectance-Fourier transform infrared (ATR-FTIR) spectroscopy for adsorbed species at 25°C. The electrophoretic mobility measurements were also conducted at 25°C to assess the coordination mechanism of adsorbed species at 25°C. The uranyl hydrolysis species and uranyl tricarbonato species coexist in solution at 25°C. At the same temperature, both species were found to be adsorbed. ATR-FTIR could confirm the adsorption of uranyl tricarbonato species at 25°C, and the electrophoretic mobility measurements suggested that the reaction mechanism is an inner-sphere coordination. However, in comparison with aqueous speciation at 25°C, at elevated temperatures the available pH range of uranyl tricarbonato species was narrow and that for uranyl hydrolysis species was wider. It was evident that two hydrolysis species are adsorbed at elevated temperatures, but no tricarbonato species. The enhanced U(VI) adsorption was observed with temperatures. This could result from the transition of dominance from the concurrent adsorption of uranyl hydrolysis species and uranyl tricarbonato species to two hydrolysis species. It was seen that the trend of enthalpy of adsorption was endothermic. Combining the present results with temperature-dependent adsorption studies on silica and aluminosilicates, a reliable SCM for the subsurface system can be proposed to explain U(VI) migration.

Compressive strength and failure behaviour of fibre reinforced concrete at elevated temperatures

Shaikh, F.U.A.,Taweel, M. Techno-Press 2015 Advances in concrete construction Vol.3 No.4

This paper presents the effects of elevated temperatures of $400^{\circ}C$ and $800^{\circ}C$ on the residual compressive strength and failure behaviour of fibre reinforced concretes and comparison is made with that of unreinforced control concrete. Two types of short fibres are used in this study e.g., steel and basalt fibres. The results show that the residual compressive strength capacity of steel fibre reinforced concrete is higher than unreinforced concrete at both elevated temperatures. The basalt fibre reinforced concrete, on the other hand, showed lower strength retention capacity than the control unreinforced concrete. However, the use of hybrid steel-basalt fibre reinforcement recovered the deficiency of basalt fibre reinforced concrete, but still slightly lower than the control and steel fibres reinforced concretes. The use of fibres reduces the spalling and explosive failure of steel, basalt and hybrid steel-basalt fibres reinforced concretes oppose to spalling in deeper regions of ordinary control concrete after exposure to above elevated temperatures. Microscopic observation of steel and basalt fibres surfaces after exposure to above elevated temperatures shows peeling of thin layer from steel surface at $800^{\circ}C$, whereas in the case of basalt fibre formation of Plagioclase mineral crystals on the surface are observed at elevated temperatures.

밭토양 양분과 비점오염물질 변동에 대한 상승온도의 영향

홍성창(Sung-Chang Hong),허승오(Seung-Oh Hur),최순군(Sun-Gun Choi) 유기성자원학회 2017 유기성자원학회 학술발표대회논문집 Vol.2017 No.3

Climate change inducing higher temperature can affect not only crop growth, yield but also availability of soil nutrient, chemical fertilizer, and manure in agricultural field. There is little information about the effect of higher temperature on non-point source pollutant of paddy and upland field runoff. Therefore, the objective of the study was to investigate the effects of elevated temperature on nutrient and dynamic of non-point source pollutant in upland soils. Temperature treatments were consisted of ambient as a control, ambient plus 2℃ and ambient plus 4℃, respectively. Each elevated temperature controlled by ten step alternating temperature programming using incubator. Content of soil and water NH4+-N, NO3--N, total nitrogen, and total phosphorus were measured. Dissolved nitrogen (N) and phosphorus (P) of maize straw were measured additionally. Treated with ambient plus 2℃, mineralization (NH4+-N/TN) of nitrogen decreased in sandy loam soils, whereas that of clay loam soils increased compared to ambient. With ambient plus 2℃ treatment, nitrification(NO3--N) of nitrogen increased in two types of soil. Concentrations of soil phosphorus and potassium showed increasing trend with the elevated temperature. Nitrate concentrations of filtered water were higher than those of ambient. Concentrations of dissolved nitrogen (N) and phosphorus of maize straw significantly increased by elevated temperature within three to five days. Thus, it was considered that in an environment higher than current temperature, water soluble nitrogen (NO3--N) and phosphorus (PO4--P) of crop residue could be released easily by rain from the agricultural fields. Therefore, upland field scale experiments are needed under natural environment using practical open top chamber. Overall, it wassuggested that elevated temperatures have effect on acceleration of mineralization and nitrification of soil nitrogen under climate change environment.

대기 중 CO₂ 상승 조건에서 재배되는 콩의 광합성과 생장 반응의 분석

오순자 ( Soonja Oh ),고석찬 ( Seok Chan Koh ) 한국환경과학회 2017 한국환경과학회지 Vol.26 No.5

The effects of elevated atmospheric CO₂ on growth and photosynthesis of soybean (Glycine max Merr.) were investigated to predict its productivity under elevated CO₂ levels in the future. Soybean grown for 6 weeks showed significant increase in vegetative growth, based on plant height, leaf characteristics (area, length, and width), and the SPAD-502 chlorophyll meter value (SPAD value) under elevated CO₂ conditions (800 μmol/mol) compared to ambient CO₂ conditions (400 μmol/mol). Under elevated CO₂ conditions, the photosynthetic rate (A) increased although photosystem II (PS II) photochemical activity (F_v/F_m) decreased. The maximum photosynthetic rate (A_max) was higher under elevated CO₂ conditions than under ambient CO₂ conditions, whereas the maximum electron transport rate (J_max) was lower under elevated CO₂ conditions compared to ambient CO₂ conditions. The optimal temperature for photosynthesis shifted significantly by approximately 3°C under the elevated CO₂ conditions. With the increase in temperature, the photosynthetic rate increased below the optimal temperature (approximately 30°C) and decreased above the optimal temperature, whereas the dark respiration rate (R_d) increased continuously regardless of the optimal temperature. The difference in photosynthetic rate between ambient and elevated CO₂ conditions was greatest near the optimal temperature. These results indicate that future increases in CO₂ will increase productivity by increasing the photosynthetic rate, although it may cause damage to the PS II reaction center as suggested by decreases in F_v/F_m, in soybean.

Sequestration of Roots-derived Carbon in Paddy Soil under Elevated CO2 with Two Temperature Regimes as Assessed by Isotope Technique

( Won Jin Baek ),( Young Joo Kim ),( Seok In Yun ),( Sun Il Lee ),( Sang Sun Lim ),( Han Yong Kim ),( Kwang Sik Yoon ),( Soo Myung Choi ),( Woo Jung Choi ) 한국응용생명화학회 2011 Applied Biological Chemistry (Appl Biol Chem) Vol.54 No.3

Paddy soils are considered to have a great soil organic carbon (SOC) sequestration potential. The present study was conducted to estimate the amount of new C derived from rice-roots in a paddy soil under global warming with elevated CO2 concentration ([CO2]) using δ13C technique. Roots of rice grown with elevated [CO2] were significantly depleted in 13C by more than 6‰ compared to those with ambient [CO2], leading to a low δ13C of SOC via rhizodeposition of 13C-depleted C under elevated [CO2]. The net C storage derived from roots was estimated to be 0.25 and 0.31 kg m-2 under ambient and elevated air temperature (Tair) conditions, respectively. The greater roots-derived C under elevated Tair than that under ambient Tair collaborated with increased root biomass by elevated Tair. However, SOC balance analysis revealed that 0.16 and 0.21 kg m-2 of autochthonous SOCs were decomposed under ambient and elevated Tair, respectively, during the growth season. Therefore, elevated Tair may enhance incorporation of new C derived from roots to SOC pool due to increased belowground biomass, but warming may also increase decomposition of old SOC by stimulating temperature-sensitive microbial activities.

온도와 CO2 농도 증가에 따른 다릅나무와 백당나무의 생장, 광합성 및 광색소 함량 변화

한심희 ( Sim Hee Han ),김두현 ( Du Hyun Kim ),김길남 ( Gil Nam Kim ),이재천 ( Jae Cheon Lee ) 한국농림기상학회 2011 한국농림기상학회지 Vol.13 No.3

The impacts of elevated temperature and CO2 were studied on the seedlings of Maackia amurensis and Viburnum opulus var. calvescens. The seedlings were grown in controlled-environment growth chambers with four combinations of temperature and CO2 treatments: 25oC + ambient CO2 (400 ppm), 25oC + elevated CO2 (800 ppm), 30oC + ambient CO2 (400 ppm), and 30oC + elevated CO2 (800 ppm). Under elevated temperature and CO2 concentration, the dry weight decreased in seedlings of M. amurensis, but increased in seedlings of V. opulus var. calvescens. In addition, the shoot to root (S/R) ratio in M. amurensis reduced but that of V. opulus var. calvescens increased under elevated CO2 concentration. The S/R ratios of two tree species increased under higher temperature. M. amurensis represented lower carboxylation efficiency under higher temperature and CO2 concentration and that of V. opulus var. calvescens showed lower values under the only higher temperature. Photosynthetic pigment content of in the leaves of M. amurensis was lower under higher CO2 concentration and higher under the increase of temperature, but that of V. V. opulus var. calvescens decreased according to the increase of temperature. Chlorophyll a/b ratios of M. amurensis and V. V. opulus var. calvescens decreased obviously with the increase of CO2 concentration and temperature, respectively. In conclusion, the growth and physiological responses under the environmental changes such as temperature and CO2 concentration depend on the tree species. Therefore, more studies are needed to predict the response of each tree species against the climate changes.

Bond behavior between circular steel tube and high-strength concrete after elevated temperatures

Ji Zhou,Zongping Chen,Maogen Ban,Yunsheng Pang 국제구조공학회 2022 Structural Engineering and Mechanics, An Int'l Jou Vol.84 No.5

In this paper, bond-slip behavior of high strength concrete filled circular steel tube (HSCFCST) after elevated temperatures treatment was studied. 17 specimens were designed for push-out test. The influence was discussed as following parameters: (a) concrete strength, (b) constant temperature, and (c) bond length. The results showed that (1) after elevated temperatures treatment, the bond strength of the HSCFCST specimens increased first and then decreased with temperature rising; (2) the bond strength increased with the increase of concrete strength at room temperature, while the influence subsided after elevated temperatures treatment; (3) the strain of the circular steel tube was distributed exponentially along its length, the stress changed from exponential distribution to uniform distribution with the increase of load; (4) the bond damage process was postponed with the increase of constant temperature; and (5) the energy consumption capacity of the bonding interface increased with the rise of concrete strength and constant temperature. Moreover, computational formulas of ultimate and residual bond strength were obtained by regression, and the bond-slip constitutive models of HSCFCSTs after elevated temperatures was established.