Japanese Journal of Farm Work Research
Online ISSN : 1883-2261
Print ISSN : 0389-1763
ISSN-L : 0389-1763
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Volume 49, Issue 4
Displaying 1-5 of 5 articles from this issue
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Research papers
  • Effects of Soil Compression after Sowing Using a Shallow Rototiller Plus Seeding Machine Capable of Cutting Small Ditches
    Yutaka SASAKI, Teruo WATANABE, Yukimine NAKANISHI, Masahiko TANIO, Kun ...
    2014 Volume 49 Issue 4 Pages 143-154
    Published: December 20, 2014
    Released on J-STAGE: June 20, 2015
    DOIhttps://doi.org/10.4035/jsfwr.49.143
    JOURNAL FREE ACCESS
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    To support crop-rotation systems using rice, wheat, and soybean in paddy fields, we developed a sowing device that can be attached to a rototiller ; the device cuts small ditches on both sides of groups of rows of plants, while tilling to a depth of approximately 5 cm, planting seeds, and compressing the soil around the seeds. This device includes a pressurized roller which compacts the soil with sowing, and we examined the effect of this compaction on germination rate after seeding. The roller provides three settings : The setting of strong pressure is compressing the soil to the level of the original topsoil. The setting of weaker pressure is compressing to leave the tilled soil 1.5 cm above the original topsoil level. The non pressure setting does not apply pressure during seeding. The strong pressure produced a higher rice germination rate than the weaker pressure and the non pressure in March 2011, but did not affect rice yield. The weaker pressure produced higher germination and growth rates than with the strong pressure and non pressure settings for wheat. In a soybean, it was not able to be recognized which pressurized setting was higher a germination rate. The strong pressure increased soil volumetric water content in the surface layer to a depth of 5 cm layer from topsoil compared with the weaker pressure and non pressure. The setting of pressurized roller made contracting soil from topsoil to depth 6-8 cm, and this condition was retained after 3 months from sowing.
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  • Characteristic and Utilization for Mobile NDVI Sensor
    Futoshi SASAKI, Noriyuki MURAKAMI, Satoshi HAYASHI
    2014 Volume 49 Issue 4 Pages 155-161
    Published: December 20, 2014
    Released on J-STAGE: June 20, 2015
    DOIhttps://doi.org/10.4035/jsfwr.49.155
    JOURNAL FREE ACCESS
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    GreenSeeker Handheld Crop Sensor (GHCS), which was recently introduced in Japan, provides the user with real-time normalized difference vegetation index (NDVI) data. In this experiment, GHCS values were compared with vegetation cover ratio and chlorophyll meter (SPAD) value for grass, wheat, and soybean to clarify the measurement characteristic. In the grass data, GHCS value showed high correlation between the vegetation cover ratio and SPAD value (R2=0.9595, 0.7748). In particular, the SPAD value under high vegetation cover ratio (more than 98%) was highly correlated with the GHCS value. The results suggested that it is possible to estimate the vegetation cover ratio and SPAD value from the GHCS value of grass. The GHCS value of wheat showed high correlation with either the vegetation cover ratio or the number of stems. On the other hand, for soybean, the correlations between the GHCS value and vegetation cover ratio and between the GHCS and SPAD values were lower than that of grass. Thus, in the experiments, the leaves of soybean showed different reflectance because of the different leaf types—light yellow, pubescent, and leaf that turned inside out.
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