Journal of the Japanese Society of Soil Physics

[title in Japanese]

[in Japanese]

2016 Volume 133 Pages 1-3
Published: 2016
Released on J-STAGE: July 14, 2021

DOIhttps://doi.org/10.34467/jssoilphysics.133.0_1

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Relationship between continuous air content and air conductivity in a sandy soil based on acoustic measurements

Kotaro FUKADA, Yasutaka KIHARA

2016 Volume 133 Pages 5-9
Published: 2016
Released on J-STAGE: July 14, 2021

DOIhttps://doi.org/10.34467/jssoilphysics.133.0_5

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Soil air conductivity has a hysteretic relation-ship with the air content of the soil, likely caused by amount of entrapped air depending on the wetting or dry-ing history of the soil. Entrapped air content can be eval-uated as the difference between total air content according to the volumetric water content and continuous air content based on the acoustic measurements. Acoustic tests were conducted for a 50-cm3 cylindrical container filled with Tottori Dune sand at several stages in the drainage or imbi-bition process. We evaluated a relationship between con-tinuous air content and air conductivity, as well as the ef-fects of entrapped air on the hysteresis. Air was entrapped in the course of imbibition of water for the total air content from 15 % to 10 %. Within this total air content range, air conductivity was found to be uniquely determined with the continuous air content. Since almost no air was entrapped for the total air content exceeding 15 %, continuity of air in the soil depending on wetting or drying was assumed to be a main reason for the air conductivity – total air content hysteresis.

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Development of prediction formula on rice establishment with corn penetrometer measurements for dry-seeding of rice with lower sowing rate in southern part of Okayama Prefecture

Hidetoshi MOCHIZUKI, Hiroshi FUJIMOTO, Yuta SHIMIZU, Hidehiro TAKAHASH ...

2016 Volume 133 Pages 11-18
Published: 2016
Released on J-STAGE: July 15, 2021

DOIhttps://doi.org/10.34467/jssoilphysics.133.0_11

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Because farming fields have recently been get-ting consolidated and farmers land also have been getting large-scale, dry-seeding of rice is widely introduced by the farmers. Our objective of this paper was to clarify whether the penetration resistance distribution measured using a corn penetrometer (SR-II) can be used to diagnose soil-layers affecting rice establishment rate and to develop a formula to predict the averaged establishment rate level of rice based on the results of diagnoses. We measured the penetration resistance distribution using a corn penetrom-eter and evaluated the establishment rate of rice at 52 dry-seeding paddy fields with lower sowing rate in southern part of Okayama prefecture. We analyzed the trend of mea-sured penetration resistance distributions for each level of the establishment rate. We proposed 5 sets of the diagnose index and criterion based on the trends of penetration resis-tance distribution, and the previous cultivation guidelines for rice. By using these sets of index and criterion, we gave scores to all the fields, and calculated the averaged level of establishment rate for each field-score. There was a high correlation between the given field-score and the averaged levels of establishment rate. We concluded that the penetration resistance distribution can be used for the diagnosis on the soil-layers of paddy fields, and we developed a for-mula to predict the averaged establishment rate level of rice by using the field-score according to the indices and crite-ria.

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Multipoint soil moisture measurements in an agricultural field with a sensor network system using a FieldRouter

Yuki KOJIMA, Ayaka YAMASHITA, Tetsu ITO, Shoichi MITSUISHI, Masaru MIZ ...

2016 Volume 133 Pages 19-27
Published: 2016
Released on J-STAGE: July 16, 2021

DOIhttps://doi.org/10.34467/jssoilphysics.133.0_19

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A FieldRouter (FR) is equipment which wire-lessly connects a variety of sensors and dataloggers, col-lects measured data, and transfers the data to a webserver via mobile telephone communication. The FR has an ad-vantage of having a small power requirement so that it can work stably in harsh environments. The FR and adequate multiple soil moisture sensors work as a sensor network system to measure multipoint soil moisture in a small farm field. In this study, multipoint soil moisture in a cold up-land cabbage field during winter season were measured with a sensor network system using the FR that included eight dataloggers and thirty soil moisture sensors. The ef-fectiveness of the system was evaluated. Dynamic changes in soil moisture due to soil freezing and thawing, and dif-ferent trends of soil moisture at each point due to differ-ent freezing and thawing rates were observed with the sen-sor network system using FR. The overall data collection rate was 86 % since some data were lost because of power supply problem of the datalogger and the network adapter. The FR sensor network system was found to be enough ef-fective for multiple soil moisture monitoring, however, the improvement is in progress for precise water management in small scale farmlands.

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Physical properties of paddy soils in Iitate Village, Fukushima Prefecture

Yohei KATSUTA, Eito KIMURA, Tomoko ICHIDA, Yasushi MORI, Kosuke NOBOR ...

2016 Volume 133 Pages 29-36
Published: 2016
Released on J-STAGE: July 16, 2021

DOIhttps://doi.org/10.34467/jssoilphysics.133.0_29

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Transport of 137Cs in soil may be important to establish a decontamination scheme for contaminated ar-eas. As a monovalent cation 137Cs is supposed to be trans-ported by diffusion and convection processes like other aqueous cations, soil hydraulic properties rule the trans-port. To provide a simulation model with basic physi-cal properties, we investigated clay minerals and hydraulic properties of soils collected from the rice paddies of 15 locations in Iitate Village. Because all the soil samples mostly contained Al-vermiculite, illite, and chlorite that tended to fix 137Cs in their structures, 137Cs might stay near the surface layer for a long time but might not contaminate groundwater.

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Report of the seminar on electrokinetic phenomena and introduction of the electrokinetic society of Japan

Atsushi YAMAGUCHI

2016 Volume 133 Pages 37-40
Published: 2016
Released on J-STAGE: July 16, 2021

DOIhttps://doi.org/10.34467/jssoilphysics.133.0_37

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[title in Japanese]

[in Japanese]

2016 Volume 133 Pages 41
Published: 2016
Released on J-STAGE: July 16, 2021

DOIhttps://doi.org/10.34467/jssoilphysics.133.0_41

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[title in Japanese]

[in Japanese]

2016 Volume 133 Pages 43-44
Published: 2016
Released on J-STAGE: July 16, 2021

DOIhttps://doi.org/10.34467/jssoilphysics.133.0_43

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[title in Japanese]

[in Japanese]

2016 Volume 133 Pages 47
Published: 2016
Released on J-STAGE: July 16, 2021

DOIhttps://doi.org/10.34467/jssoilphysics.133.0_47

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