Japanese Journal of Grassland Science
Online ISSN : 2188-6555
Print ISSN : 0447-5933
ISSN-L : 0447-5933
Current issue
Displaying 1-5 of 5 articles from this issue
Research Papers
  • Tomohiro Kikawada, Yasuharu Sanada, Masahiro Fujimori, Shigemitsu Kasu ...
    2024 Volume 70 Issue 1 Pages 1-9
    Published: April 26, 2024
    Released on J-STAGE: May 28, 2024

    In order to reduce labor and improve objectivity in orchard grass (Dactylis glomerata L.) breeding and selection, we obtained vegetation index rG from aerial images taken by unmanned aerial vehicle (UAV) and correlated it with the overall evaluation of grass vigor, disease severity, and overwintering performance by breeders using the conventional method. However, there was no correlation between overwintering performance and rG at the time of evaluation. Comparisons of overwintering performance, disease severity, and yield of the selected individuals showed that the rG selection was almost equal to or slightly superior to the conventional method. In perennial ryegrass (Lolium perenne L.), intergenerational comparisons with the parent material showed that the rG selection increased the annual yield of the parent material by 103-107 %. These results indicate that the rG selection can be used as a labor-saving and objective selection method, and that it is as effective as selection by breeders.

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  • Toshiya Saigusa, Tetta Matsuyama, Yuki Miyamura, Yoshito Takebayashi, ...
    2024 Volume 70 Issue 1 Pages 10-21
    Published: April 26, 2024
    Released on J-STAGE: May 28, 2024

    The applicability of the fertilizer recommendation estimation method developed for cattle grazed swards to sheep and horse grazed swards in Hokkaido was examined. For each pasture, the weight of grazing livestock was totaled per area, and 2.38% of the weight was estimated to account for herbage consumption. Using herbage consumption as an independent variable, we calculated the nitrogen, phosphorus, and potassium requirement using an estimation formula derived from the cattle grazing experiment. The difference between the fertilizer requirement and annual fertilizer application rate was used to obtain nutrient balance. The nutrient balance was compared with the changes in soil nutrients before and after grazing to verify the validity of the fertilizer requirements. The results of our estimation were consistent with those obtained from the cattle pasture experiment with the same level of accuracy. Relatively large outliers were assumed to be caused by land conditions such as slope and drainage permeability, and management conditions such as grazing pressure. This study made it possible to plan annual fertilizer application according to the total weight of sheep and horses during the grazing season, which was assumed at the time of grazing planning, based on the same logic as for cattle.

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  • Akira Yajima, Makoto Miyaji
    2024 Volume 70 Issue 1 Pages 22-27
    Published: April 26, 2024
    Released on J-STAGE: May 28, 2024

    We explored the effect of mixing alfalfa with orchardgrass in different ratios on the fermentation profile of silage when harvested three times a year. Alfalfa and orchardgrass were harvested and mixed in fresh weight ratios of 100 : 0 (O0), 70 : 30 (O30), 50 : 50 (O50), 30 : 70 (O70), and 0 : 100 (O100) for the 1st, 2nd, and 3rd harvests, respectively. After mixing, materials were chopped to 2 cm, wilted for 24 h, and ensiled for 90 days. The wilted materials with a greater proportion of orchardgrass had lower crude protein content and buffering capacity, and higher water soluble carbohydrate content, regardless of the harvest number. The materials of the 1st harvest had lower dry matter content and higher water soluble carbohydrate content than those of 2nd and 3rd harvests for all mixing ratios. With an increasing proportion of orchardgrass, the silage lactic acid content increased, and pH decreased for the 1st harvest. A V-score of more than 60 was observed in O70-100 of the 1st harvest, which indicated that silage fermentation quality was better when alfalfa was ensiled in a mixture with about 70% orchardgrass. On the other hand, materials were not fermented well for the 2nd and 3rd harvests, regardless of the orchardgrass ratios.

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Special Features
The Poster-presentation by High-school Students at the Annual Meeting of the Japanese Grassland Society 2023