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Volume 53 (2018)
- Issue 4 Pages 164-
- Issue 3 Pages 125-
- Issue 2 Pages 73-
- Issue 1 Pages 3-
Volume 53, Issue 3
Displaying 1-4 of 4 articles from this issue
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Review
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Masakazu Komatsuzaki2018 Volume 53 Issue 3 Pages 125-132
Published: 2018
Released on J-STAGE: March 20, 2019
JOURNAL FREE ACCESSSingle cropping and continuous cropping are agricultural practices of serious concern in Japan. However, cover crops may help mitigate the effects and contribute to local environmental conservation and sustainable crop productivity. This paper discusses the significance of cover crops to the agroecosystem in relation to the tillage system. According to our literature survey, cover crops improve soil carbon sequestration, scavenge residual soil nitrogen, and provide nitrogen to subsequent crops. This cover crop performance has great potential for developing unique conservation agriculture practices because cover crops have many benefits in comparison to manure or compost application.View full abstractDownload PDF (997K)
Original Paper
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—A New Vegetation Index Combining Chlorophyll Index and Solar Radiation—Motoharu Murata, Hiroki Yamashita, Kouichi Adachi, Saori Hida, Tatsuya ...2018 Volume 53 Issue 3 Pages 133-142
Published: 2018
Released on J-STAGE: March 20, 2019
JOURNAL FREE ACCESSWe tested if a new vegetation index, which combines the chlorophyll index and a measure of solar radiation (Σ (CI×I) ) , could estimate the dry matter weight (DMW) of soybeans by proximal remote sensing. In each year of the three-year experiment, we made two kinds of soybean communities which had different row spaces. We judged the usefulness of Σ (CI×I) by comparing it to both the ratio vegetation index (RVI) and an index combining the normalized differential vegetation index and solar radiation (Σ (NDVI×I) ). The values of Σ (CI×I) and Σ (NDVI×I) were found by the following methods. We measured CI and NDVI 3–6 times over the soybean growth period using a handy-type-spectral-reflectance-measuring-device and estimated a daily value of the CI and NDVI by using spline-smoothing regression method. Then, we multiplied CI or NDVI by solar radiation (MJ/m2/day) , and summed this value over a period from the sowing date to the DMW measurement date of the soybeans. We measured DMWs of soybeans 3 - 6 times during the growth periods, and we examined the relationship between the indices and DMW of soybeans. As a result, Σ (CI×I) was significantly related to the DMW, and had the least root square mean value (RMSE) of the three indices. The values of RMSE over the growth period were 98.5, 337.0, and 113.7 for Σ (CI×I) , RVI, and Σ (NDVI×I) , respectively. This was because the Σ (CI×I) in a reproductive period had the least RMSE of the three indices. These results indicate that the new vegetation index of Σ (CI×I) could estimate the dry matter weight of soybean more precisely than other indices over a soybean growth period.View full abstractDownload PDF (1497K)
Research paper
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Futoshi Sasaki, Tomohiro Nozawa, Tadayuki Kudo2018 Volume 53 Issue 3 Pages 143-148
Published: 2018
Released on J-STAGE: March 20, 2019
JOURNAL FREE ACCESSIn this experiment, we investigated the effects of pinching on the growth and yield of a local green soybean, “kemame,” and evaluated the effect of introducing a pinching machine and a harvest machine on farm management. We observed that the pinching mistake rate was less than 4% when the pinching machine was operated at a speed of about 0.5 m/s and pinching was done at a position 10 cm below the top of the main stem. The yield remained unaffected when pinching was done at the 9th leaf stage and flowering stage. The harvest loss in the case of pinched plant was significantly lower than in the case of untreated plant when the harvest machine was used. Thus, the introduction of pinching and harvest machines in the cultivation of “kemame” has the potential to decrease the harvest loss about 10% and reduce the working time 20% or less, resulting in increased profits.View full abstractDownload PDF (1338K) -
Naomi Asagi, Yoshihito Kubota, Nobuo Sakagami, Takuya Okada, Morifumi ...2018 Volume 53 Issue 3 Pages 149-157
Published: 2018
Released on J-STAGE: March 20, 2019
JOURNAL FREE ACCESSThe objective of this study is to evaluate the influence of sweet sorghum (SS) cultivation and the application of SS aboveground residues on growth, yield and curcumin content of turmeric. The soils in SS cultivation area and SS non-cultivation area were placed into Wagner pots (diameter: 16 cm, height: 19 cm) in a greenhouse. The pots with SS cultivated soil and SS non-cultivated soil were subjected to four treatments: (1) no fertilizer (NF) , (2) chemical fertilizer (CF) , (3) CF with SS residue incorporation into the soil (INC) , and (4) CF with SS residue surface application (SUR). One seed-rhizome (20 g) of turmeric per pot was planted on June 2, 2017. The aboveground portion and rhizome of turmeric were harvested on December 6, 2017. The exchangeable K2O concentration in SS cultivated soil was significantly higher than that in SS non-cultivated soil before turmeric planting. Soil moisture content in the early growth stage of turmeric was higher in SUR than in other treatments in both SS cultivated and non-cultivated soils. Dry weight and curcumin content of turmeric rhizome at harvest were higher in SS cultivated soil than in SS non-cultivated soil and was higher in SUR than in other treatments. From these results, SS cultivation increased soil exchangeable K2O concentration and SS residue surface application increased soil water retentivity, which might increase the yield of turmeric and curcumin content.View full abstractDownload PDF (1321K)
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