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Volume 60, Issue 3
September
Displaying 1-6 of 6 articles from this issue
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Invited Review Papers
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Owen T. DENMEAD2004 Volume 60 Issue 3 Pages 163-171
Published: 2004
Released on J-STAGE: May 09, 2006
JOURNAL FREE ACCESSAnimal production systems are major agricultural sources of the greenhouse gases, methane and nitrous oxide, of pollutants such as ammonia and hydrogen sulfide, and of odours. Verifying inventory estimates of their production, and monitoring, regulating and reducing their emission all require the ability to make precise, non-obtrusive measurements of their fluxes, and in the case of odours, an ability to predict concentrations close to the source. However, these requirements present special problems. The source areas are often small or irregularly shaped, the sources may be distributed heterogeneously, and emissions may be transient. Odours present an additional problem in that it is difficult to quantify their intensity since they are usually due to a mixture of more than 100 volatile organic compounds. The use of tracer gases to follow odour dispersion is discussed, but quantifying odour intensity is a pressing problem. The paper considers measurement techniques appropriate for sources of different shapes and sizes. Most attention is given to small and irregularly shaped sources for which conventional, large-area micrometeorological approaches are inapplicable: line-sources, strips, small plots, and waste storage areas such as ponds and manure piles. Mass balance techniques appear to be particularly useful for these purposes. Various applications of the methodology are considered in some detail. The advent of open-path gas lasers that can measure concentrations rapidly and over distances of hundreds of meters is seen as a significant development. Finally, the paper considers the use of a Lagrangian dispersion model that allows emissions from sources of any geometry to be linked to concentrations at any location downwind. In forward mode, it can predict downwind concentrations for given source scenarios, while in backward mode, it can infer fluxes from measurements of concentration and wind speed at just one height downwind. It is a very attractive tool for use in many dispersion problems relevant to the theme of the paper.View full abstractDownload PDF (607K)
Full Papers
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Naru TAKAYAMA, Reiji KIMURA, Makio KAMICHIKA, Nobuhiro MATSUOKA, Xingc ...2004 Volume 60 Issue 3 Pages 173-189
Published: 2004
Released on J-STAGE: May 09, 2006
JOURNAL FREE ACCESSWe have researched environmental monitoring to support anti-desertification activities in the Loess Plateau. In this thesis, the spatial distribution, the variance (stability) and the trend of annual precipitation were studied. In addition, the stability of precipitation in the summer rainy season was estimated from the viewpoint of seasonal features of precipitation. The sampling distribution of the mean of the annual precipitation was resampled by the Bootstrap method at each observation point, and the mean of the annual precipitation was estimated by interval estimation. The time series trend of the annual precipitation was analyzed by using the interval estimation mean of the annual precipitation. The stability of precipitation in the summer rainy season was analyzed from the relationship between the precipitation ratio and the precipitation stability index for the period of five days. It seems that the mean of annual precipitation was the lowest in the Tengeri Desert and the Wulanbu Desert. But the region on the Quilian mountain range at the west side of those deserts near Menyuan had much precipitation. The rainfall increased in low-latitude regions. The variation of annual precipitation was the largest in the northern Maowusu Desert, the northeastern Wulanbu Desert, and around Wugong. In contrast, the variations of annual precipitation were small around Menyuan. We could not see a trend for annual precipitation in the whole of the Loess Plateau from 1980 to 2000. However, it seems that there were significant trends at a few observation points. We proposed the rainy season stability index {RSS(j)} based on the relationship between the precipitation ratio PRP(t, j) and the precipitation stability index PSI(t, j). The analysis of the feature of precipitation by using RSS(j) clarified that the rainy season is not equally stable between the east side and the west side of the Loess Plateau, even if the annual precipitation is at the same level.View full abstractDownload PDF (1327K)
Short Papers
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Hiroshi HAMAMOTO, Hideo SHIMAJI, Tadahisa HIGASHIDE2004 Volume 60 Issue 3 Pages 191-195
Published: 2004
Released on J-STAGE: May 09, 2006
JOURNAL FREE ACCESSWe investigated varietal differences in reproductive responses of spinach (Spinacia oleracea L.), a long-day plant, to 2-h night-break treatments with light of various wavelengths provided by light-emitting diodes of various colors. In the first experiment, medium-early-bolting cv. ‘Alrite’ and late-bolting cv. ‘Summer Focus’ were treated with blue, green, yellow, red, far-red, or no light. Both cultivars showed high night-break sensitivity to red, yellow, and green light and low sensitivity to blue light for bolting, but ‘Alrite’ was much more sensitive to far-red light than ‘Summer Focus.’ In the second experiment, we added medium-early-bolting cv. ‘Atlanta’ and late-bolting cv. ‘Active.’ These cultivars were night-broken by red, far-red or no light. Bolting of earlier-bolting cultivars ‘Alrite’ and ‘Atlanta’ was accelerated more by far-red night-break treatment than that of later-bolting cultivars ‘Active’ and ‘Summer Focus.’ These results suggest that earlier-bolting cultivars of spinach have a wider range of effective night-break wavelengths for bolting than later-bolting cultivars.View full abstractDownload PDF (441K)
Full Papers (in Japanese)
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Keisuke NONAKA, Masatoshi AOKI, Katsutoshi HORIE2004 Volume 60 Issue 3 Pages 197-207
Published: 2004
Released on J-STAGE: May 09, 2006
JOURNAL FREE ACCESSIn the present study, we measured the CO2 flux from soil surface of humic andosol under sustainable agricultural practices such as crop rotation, reduced tillage and manure application. We then evaluated the level of the CO2 flux and investigated the factor which controlled the CO2 flux under those practices. The CO2 flux was measured by open chamber technique from July in 1999 to October in 2001 in the experimental field of Tokyo University of Agriculture and Technology (Fuchu, Tokyo) where the soil was humic andosol and the same practices have been continued for 8years. The CO2 flux under maize cultivation in 1999, wheat in 2000, soybean in 2000, wheat in 2001 and maize in 2000 ranged 0.56-1.16, 0.01-0.37, 0.01-0.41, 0.07-0.39 and 0.22-0.67 g CO2m-2h-1, respectively. A strong relationship appeared between CO2 flux in each crop growing period and soil temperature (R2=0.75-0.86). The average CO2 flux from soil surface in the maize growing period in 1999 was five times larger than that in the soybean growing period in 2000, and the average CO2 flux from soil surface in the wheat growing period in 2001 was twice larger than that in the wheat growing period in 2000. The level of CO2 flux in each crop growing period was strongly related to the amount of applied nitrogen, including the preceding crop residue in addition to manure (R=0.988). Q10 under maize cultivation, soybean and wheat were 2.3-2.4, 16.2 and 2.8, respectively. Carbon emissions of soybean-wheat rotation and maize-wheat rotation were estimated as 296 g Cm-2 and 578 g Cm-2, respectively. This result suggests that it is possible to decrease carbon loss from soil by crop rotation incorporating soybean cultivation in humic andosol, since soybean demands less nitrogen application than other crops because of its nitrogen-fixing ability.View full abstractDownload PDF (1322K) -
Nozomi USHIKAWA, Toru IWATA, Takeshi MIURA, Akinori OHTOU, Yoshihisa H ...2004 Volume 60 Issue 3 Pages 209-214
Published: 2004
Released on J-STAGE: May 09, 2006
JOURNAL FREE ACCESSThe Monin-Obukhov similarity theory for carbon dioxide (c) and water vapor (q) is investigated using data obtained over a rice field. First, the similarity theory is applied to the standard deviations of c and q. It is noticed that the standard deviations normalized by their friction concentrations show very similar stability dependence: σc/|c*|=3.0(1-7.0ζ)-1/3 and σq/|q*|=2.9(1-7.0ζ)-1/3 under unstable conditions, and σc/|c*|=3.0(1+7.0ζ)1/3 and σq/|q*|=2.9(1+7.0ζ)1/3 under stable conditions. This results in the situation that the correlation coefficient between c and q can be expressed as the ratio of 2.9/3.0≈1, where numerals of 3.0 and 2.9 are the value of the normalized standard deviation of c and q under neutral conditions.View full abstractDownload PDF (880K)
Short Papers (in Japanese)
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Sachiko INOHARA, Toru IWATA, Takeshi MIURA, Akinori OHTOU, Yoshihisa H ...2004 Volume 60 Issue 3 Pages 215-220
Published: 2004
Released on J-STAGE: May 09, 2006
JOURNAL FREE ACCESSTo elucidate the seasonal and inter-annual variation of CO2 exchanges between the atmosphere and paddy field, the CO2 flux has been measured by the eddy correlation technique at the experimental farm of the Agricultural Faculty, Okayama University, since December in 1998. The CO2 sensor, however, does not work under rainy conditions. The improved aerodynamic technique was developed and used to fill the gap in the eddy flux data. This technique gave reasonable CO2 fluxes even on rainy days. The reliability of the technique was also confirmed by comparing CO2 fluxes with those measured by the eddy correlation technique.View full abstractDownload PDF (898K)
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