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[in Japanese]
2010 Volume 114 Pages
1
Published: 2010
Released on J-STAGE: September 01, 2021
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Taihei MORISAWA, Yasushi MORI, Jun’ichiro IDE, Hiroaki SOMURA, Ikuo TA ...
2010 Volume 114 Pages
3-10
Published: 2010
Released on J-STAGE: September 01, 2021
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Recent increases in rainfall acidity and intensity have generated interest in their effect on soil-bound ions (i.e. mineral cations or nutrient anions) in drainage. A soil column experiment was conducted under field conditions to characterize infiltrated soil water quality resulting from simulated rainfall treatments. Two rainfall treatments (neu-tral rain and acid rain) and four rainfall intensities (2, 4, 20, 80 mm hr−1) were investigated. Water draining through the soil column was sampled and analyzed for electrical conductivity (EC) and dissolved ion concentration. Re-sults showed the acidic rain treatment caused more solute discharge than did neutral rain treatment. Infiltrated soil water quality was much higher than rain water, suggest-ing that changes in ionic concentration are due to leach-ing processes rather than ion exchanges. Moreover, high-est solute concentrations was resulted from 80 mm hr−1 rain, being affected by rainfall intensity. Surprisingly, 80 mm hr−1 intensity when combined with acid rain treatment caused higher discharge solute concentrations than either treatment independently.
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Shakil Uddin AHMED, Masateru SENGE, Kengo ITO, John Tawiah ADOMAKO
2010 Volume 114 Pages
11-16
Published: 2010
Released on J-STAGE: September 01, 2021
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An experiment was conducted in a vinyl house at Gifu University, Japan, from June to November 2008 to assess the effect of water stress on nodulation of uninoc-ulated soybean and leaf N accumulation to grain yield at three different growth stages of soybean. The experimental design was a randomized complete block of five treatments with nine replications. The deficit irrigation treatments im-posed were D1 (0 – 20 %), D2 (20 – 40 %), D3 (40 – 60 %), D4 (60 – 80 %) and D5 (80 – 100 %) of water deficit total available water (TAW). The three growth stages were flow-ering (49 DAS: days after sowing), seed growth (77 DAS), and maturity (140 DAS). The highest leaf N accumulation was in the D2 treatment at the flowering and seed growth stage. The soybean grain yield had positive significant cor-relation (p < 0.01) with leaf nitrogen at seed growth stage. Total nodule numbers at ≥ 4.75 mm diameter size had non-significant effect on leaf N accumulation, but had positive significant effect (p < 0.05) on grain yield of soybean at seed growth and maturity stage. On the other hand, total nodule numbers at < 4.75 mm size had positive signifi-cant effect (p < 0.01) on leaf N accumulation and grain yield of soybean at seed growth stage. Total nodule fresh and dry weight at ≥ 4.75 mm size had non-significant ef-fect on leaf N accumulation and grain yield of soybean, but nodules at < 4.75 mm size had a positive significant effect (p < 0.01) at seed growth stage. Individual nodule fresh and dry weight at ≥ 4.75 mm size showed negative signif-icant correlation (p < 0.01) with leaf N accumulation and grain yield, but nodules at < 4.75 mm size showed positive significant correlation (p < 0.01) at seed growth stage. Our studies demonstrated that the water deficit level D2 (20 – 40 % of TAW) was the best for an efficient Rhizobium-host association and subsequent nodule development. Based on our results, it can be concluded that successful root infec-tion of uninoculated soybean was more pronounced in < 4.75 mm diameter size class nodule than the larger ones (≥ 4.75 mm) under different water deficit levels.
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[in Japanese]
2010 Volume 114 Pages
17-18
Published: 2010
Released on J-STAGE: September 01, 2021
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Colin S. Campbell, Lauren L. Bissey, Douglas R. Cobos, Kelsey M. Du ...
2010 Volume 114 Pages
19-22
Published: 2010
Released on J-STAGE: September 01, 2021
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Data interpretation is a major challenge given the increasing number of wireless soil moisture sensor net-works. Although sometimes ignored, site-specific infor-mation like topography, morphology, and soil type are key to understanding soil moisture behavior. To improve our understanding of soil moisture sensor behavior, we evalu-ated three sites that were constituents of a 12 node wireless network deployed across a 37 ha field in locations selected for their geographic diversity. Each site had previously been characterized with a detailed soil profile analysis. Continuously monitored water content sensors were ins-talled at 5 depths at 30 cm spacing starting at 30 cm. Site-specific characteristics significantly affected soil water dy-namics. A hardpan in the soil explained unexpected differ-ences in soil water with depth at one site, while low land-scape position along with subsurface drainage explained another. Diurnal redistribution of water could also be seen at a third location down to 150 cm. Combining data from intensely monitored sites with plant type, topography, and soil morphology greatly improve our interpretation of soil moisture data in the field.
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Aki HOSHINO, Haruyuki FUJIMAKI, Toshiya OKURO, Kazuhiko TAKEUCHI
2010 Volume 114 Pages
23-25
Published: 2010
Released on J-STAGE: September 01, 2021
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We experienced malfunctions in soil moisture sensors (10HS, ECH2O-TE and 5TE; Decagon Devices Inc.) and different range of output value of Em5 with Em5b and Em50, through column experiments. The per-centages of malfunctions were 17 %, 0 % and 30 % for 10HS, 5TE and ECH2O-TE sensor, respectively. The mal-function was decided that the output value was too high or low to calibrate with data logger which is assumed to work. Also, we found that the range of output value of Em5 data logger was different from that of Em5b and Em50. There-fore, it is needed to specific calibration when Em5 data logger is used with other data logger (Em5b, Em50).
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Hiromi IMOTO, Taku NISHIMURA, Tsuyoshi MIYAZAKI
2010 Volume 114 Pages
27-31
Published: 2010
Released on J-STAGE: September 01, 2021
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Sensors detecting soil volumetric water content by measuring the dielectric constant of the media are be-coming popular in environmental science. Some of them such as EC-5 (Decagon devices Inc.) is convenient due to lower price and smaller size. However, it is still not clear size of region the sensor can detect moisture. In addition, some soils do not obey to the supplier distributed calibra-tion curve between output voltage and volumetric water content of the media. Here, we tried to determine size of active area around the sensor. As well, a new procedure to determine a calibration curve based on soil water retention curve is proposed.
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Yuji ITO, Hideki MIYAMOTO, Eriko YASUNAGA, Toshihiko EGUCHI, Jiro CHIK ...
2010 Volume 114 Pages
33-36
Published: 2010
Released on J-STAGE: September 03, 2021
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Moisture measurements in a hydroponic medium with growing carrot and in a rough-rice medium using ECH2O probes (EC-5, ECH2O-TE; Decagon De-vices) have been conducted as case studies on applications of the probes to the environmental control field in biology. In the hydroponics, it was difficult to apply directly EC-5 sensor to moisture measurement in the medium due to the effect of conductive nutrient solution on EC-5 output voltage. To eliminate the effect, a correction method that may be acceptable for known and stable electrical conduc-tivity condition was proposed and examined. The results showed that the correction method was useful for estimat-ing relationship between volumetric water content in the medium and the output voltage under various conductiv-ity conditions. For the rough-rice medium, the moisture decline in the drying process was confirmed by the mea-surements using EC-5 and ECH2O-TE sensors. From the experiments, we could obtain non-linear functions that are highly relating the moisture in the rough-rice medium to output voltage or relative permittivity.
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Tadaomi SAITO
2010 Volume 114 Pages
37-40
Published: 2010
Released on J-STAGE: September 03, 2021
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The Loess Plateau in northwestern China is one of the most seriously affected regions by soil ero-sion in the world. For afforestation on steep slopes in the Loess Plateau, a small scale water harvesting system, called“fish-scale-pit”, is commonly used to reduce erosion and increase soil water storage. To evaluate the effective-ness of this system, soil water and heat movements have been monitored in an experimental site using various mon-itoring devices in the north of Loess Plateau. In this pa-per, I focused on the soil water monitoring using dielectric probes in this site. ECH2O probes, models EC-5 and EC-20 (Decagon Devices), have been set at various depths in the site. Three main problems on the soil water monitoring caused by use of the probes were discussed: (i) tempera-ture dependence of the probe outputs, (ii) data loss due to breakdowns of the probes and (iii) individual variability of the probes. It is difficult for users to solve the problems (ii) and (iii); further efforts by manufactures to provide ir-refrangible and precise probes are anticipated.
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[in Japanese]
2010 Volume 114 Pages
41
Published: 2010
Released on J-STAGE: September 03, 2021
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Nobuhito OHTE, Naoko TOKUCHI
2010 Volume 114 Pages
43-47
Published: 2010
Released on J-STAGE: September 03, 2021
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Tamon FUMOTO, Tetsuji YANAGIHARA, Takashi SAITO, Kazuyuki YAGI
2010 Volume 114 Pages
49-52
Published: 2010
Released on J-STAGE: September 03, 2021
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Hajime YAMAMOTO
2010 Volume 114 Pages
53-58
Published: 2010
Released on J-STAGE: September 04, 2021
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Kosuke NOBORIO
2010 Volume 114 Pages
59-62
Published: 2010
Released on J-STAGE: September 04, 2021
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Koji INOSAKO
2010 Volume 114 Pages
63-69
Published: 2010
Released on J-STAGE: September 04, 2021
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Nobuo TORIDE, Kunio WATANABE, Hiroki MORISAKI
2010 Volume 114 Pages
71-79
Published: 2010
Released on J-STAGE: September 04, 2021
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Takeyuki ANNAKA
2010 Volume 114 Pages
81-86
Published: 2010
Released on J-STAGE: September 04, 2021
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浸潤前線不安定性は，均一な土壌において不均一な流れ（フィンガー流）を生じる要因となる。本報では，浸潤前線不安定化条件の研究の中から Parlange and Hill（1976）を紹介した．彼らは，水分拡散の影響によって浸潤前線が曲率に応じて速度低下することをモデル化し，土壌特性として水分拡散係数を考慮した安定性解析を行なった．それ以前に行なわれた安定性解析においては土壌の特性が反映されていなかったため，浸潤前線が不安定となる条件は示せても，フィンガーの大きさ（幅や直径）を土壌の特性と関連付けて議論することができなかった．フィンガーの大きさを対象としたそれ以降の研究はほとんどが彼らの示した表式を前提にしており，この研究の影響が大きかったことを示している．しかしながら，現在に至るまで給水条件，土壌特性とフィンガーの大きさや本数の関連性を明快に示す理論は見当たらない．
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[in Japanese]
2010 Volume 114 Pages
87-88
Published: 2010
Released on J-STAGE: September 04, 2021
JOURNAL
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[in Japanese]
2010 Volume 114 Pages
89-90
Published: 2010
Released on J-STAGE: September 05, 2021
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[in Japanese]
2010 Volume 114 Pages
92
Published: 2010
Released on J-STAGE: September 05, 2021
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