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Article type: Cover
1987 Volume 33 Issue 2 Pages
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Article type: Cover
1987 Volume 33 Issue 2 Pages
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Article type: Appendix
1987 Volume 33 Issue 2 Pages
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Article type: Appendix
1987 Volume 33 Issue 2 Pages
ii-iii
Published: July 31, 1987
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Toshihiro SUGIURA, Sohzoh SUZUKI, Hiroshi KOBAYASHI
Article type: Article
1987 Volume 33 Issue 2 Pages
95-101
Published: July 31, 1987
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Comparisons were made on herbage yield, grazing efficiency and botanical composition of four pastures developed by different methods. A new method emploied a stump-cutter and a bush-cutter for cleaning all the original vegetation and for incorporating item into soil surface layer whereas the other methods removed the original vegetation out of the field. Results; 1) From the first year, crushed plant residues scattered over the pasture developed by a new method became covered with the rapidly growing stoloniferous legume such as white clover, creating a legume-dominant pasture. 2) Comparing with pastures developed by the other methods, a new pasture produced lower levels of herbage for the first year, however, the yield difference between pastures smaller in the second year, producing about 3t/10a of fresh herbage. 3) In a pasture where the original vegetation was cleared but not crushed by a bush-cutter, the original vegetation started to regrow, but could be controlled by the continuous grazing managements.
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Zhongyi YANG, Kazuo SUGAWARA, Iwao ITO, Junkoh MARUYAMA, Kazuo FUKUNAG ...
Article type: Article
1987 Volume 33 Issue 2 Pages
102-108
Published: July 31, 1987
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Seed ripening and seed shedding process of orchardgrass under the deferred use and the effect of spring-cutting on seed production of orchardgrass were investigated at Obihiro (1983) and Kawatabi (1985 and 1986). Main results obtained were summarized as follows: 1) About 50% of seeds had shed from ears within 70 days after the first heading time, and most of them had ability of germination. The ear production was not affected by cutting until 10 days before first heading time. These results suggested that the resting of grazing for 80 days, from 10 days before heading to 70 days after heading, was essential to produce a sufficient amount of seeds for natural reseeding. 2) The percentage of heading of orchardgrass was higher in several early spring cutting-treatments than in no-cutting treatment. It suggested that the proper use of orchardggrass in spring presumably stimulated the formation of fertile tillers. 3) A sigmoid curve was observed in the relationship between length of harvested plant materials and rate of injured ears. A steep increase of injured ears was observed when the length of harvested part was more than 40 cm. Therefore, it suggested that there will be little influence of spring-cutting on seed production if the length of harvested part is less than 40 cm.
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Norio YOSHIDA, Michinori TOMITA, Yasuichi TAKEMASA, Tetsuji TAKAHASHI
Article type: Article
1987 Volume 33 Issue 2 Pages
109-115
Published: July 31, 1987
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The storability of forage paddy rice as affected by different conservation methods was studied. Two paddy rice lines (Tamakeita-1 and Tamakeita-2) selected for forage were cultivated and the whole plants after harvest were, 1) dried on paddy sheaf rack (RD), or 2) ensiled without drying (DCS), 3) after wilting (WS), or 4) after addition of ammonia, 0.4% (AS). Dry matter and TDN yields (kg/a) were 109.9 and 59.0 in Tamakeita-1, 116.9 and 65.2 in Tamakeita-2. Both lines had showing high panicle weight ratios and NFE contents; the characteristics of whole crop forage plant. The high contents of water-soluble carbohydrate (WSC) over 10% suggested the high silage adaptability of the crop. In the silage quality, DCS fermented better than WS and AS. There was no difference in organic matter, ADF, SiO_2, IVDMD or TDN regardless of the treatments. Total nitrogen content decreased in RD, increased in AS, but did not change significantly in DCS and WS. Among nitrogen fractions, water insoluble nitrogen decreased in RD and DCS, ammonium nitrogen increased in AS and DCS, and water soluble nitrogen increased in DCS. Addition of ammonia retarded the rising in silage temperature and growing of visible mold when silages were exposed to air.
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Toshiki ISHIGURI
Article type: Article
1987 Volume 33 Issue 2 Pages
116-120
Published: July 31, 1987
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Data reported here were obtained from 316 digestibility experiments with fresh grasses and legumes fed to whethers. The relationship between the contents (X_<CC>: %) and apparent digestibility (Y_<DCC>: %) of cell contents (CC) was determined. The relation was fittingly expressed by asymptotic regression : Y_<DIG>=98-1321/X_<CC> (r=0.78, p<0.01). The percentage of digestible CC (Y_<DCC>) increases rectilinearly as that of CC (X_<CC>) increases, and the relationship was expressed by the equation : Y_<DCC>=-13.6+0.99X_<CC> (r=0.98, p<0.01). True CC digestibility of grasses and legumes estimated from the regression was nearly 100%. Bacterial and endogeous excretion (Y_<BEE>: g/kg^<0.75>) of wethers were related with dry matter intake (X_<DMI>: g/kg^<0.75>); Y_<BEE>=0.3+0.14X_<DMI> (r=0.84, p<0.01). The nutritive availability of the cell content fractions was uniform among forages.
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Yasuhiro SUGIMOTO, Masahiko HIRATA, Masahiko UENO
Article type: Article
1987 Volume 33 Issue 2 Pages
121-127
Published: July 31, 1987
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Bahiagrass, (Pasplum notatum Flugge.), pasture (0.18 ha) was grazed eight times during the grazing season (May-Oct.) in 1983 by 21-24 Holstein heifers under rotational system with 2-4 week intervals. Amount of excreted N was estimated by following equations ; dung-N (g N/head/day)=weight of dung pat (g/pat)×No. of dung pat (pat/head/day)×N concentration of dung (%) and urine-N (g N/head/day)=volume of urine (l/urination)×No. of urination (No./head/day)×N content of urine (g N/l) 1. Amount of excreted dung-N and urine-N was much varied with grazing Nos. Differences in dung-N were largely dependent on the variations in weight of dung pat and No. of dung pat, and those in urine-N were resulted from changes in all of the determinants in the above equation. 2. Significant positive correlation was found between the amount of excreted dung-N and dry matter intake (r=0.946^*), and nitrogen intake (r=0.945^*), whereas the amount of urine-N was significantly related to mean liveweight (r=0.981^<**>), and metabolic body size (r=0.982^<**>) of heifers. 3. Amounts of excreted dung-N and urine-N during the grazing season were 101.0 kg/ha and 95.9 kg/ha, respectively. The pasture being grazed recieved 86% of dung-N and 78% of urine-N, and the remainder of 14% and 22% was deposited on the pasture served to resting for the herd (resting place). 4. The investigation suggested that a certain amount of excreted N was not recycled in the pasture through the deposition of excreta on the resting place. Especially in summer, percentage deposition of excreta on the resting place was higher and it was accounted that presumably less than 40% of excreted N were recycled in this season.
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Masahiko HIRATA, Yasuhiro SUGIMOTO, Masahiko UENO
Article type: Article
1987 Volume 33 Issue 2 Pages
128-139
Published: July 31, 1987
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Bahiagrass (Paspalum notatum Flugge.) pasture was grazed eight times by Holstein heifers under rotational system, and the locations of newly deposited dung pats and ungrazed areas were recorded after each grazing. The number of defecations by cattle during the grazing was also recorded. Distribution of dung pats, that of ungrazed areas and their relationship were analyzed with a particular attention to the progress of grazing as well as the eight individual grazings. Outlines of results are as follows. 1. When a resting place with shading trees was attached to the pasture, 11.4-29.5% of defecations took place in the resting place. 2. At individual grazings, both dung pats and ungrazed areas were distributed unevenly on the pasture. However, when the number of dung pats and the percentage of ungrazed areas at each individual grazing were accumulated through the eight successive grazings, there was a tendency that both dung pats and ungrazed areas were distributed more evenly over the pasture. 3. The dung pats deposited at a certain grazing time had a relatively small effect on the appearance of ungrazed areas in the same grazing period, but gave a significant influence on the formation of ungrazed areas during the next grazing time. 4. The ungrazed areas once formed by the dung deposition at the previous grazing were inferred to continue to exist on the pasture for further one or two grazing(s). This lead to an estimation that the effect of dung pats at a certain grazing time on the appearance of ungrazed areas lasted until the second or third grazing from the time of deposition.
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G.S. PREMACHANDRA, Tohru SHIMADA
Article type: Article
1987 Volume 33 Issue 2 Pages
140-148
Published: July 31, 1987
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Drought tolerance in orchardgrass (Dactylis gromerata L.) was measured by the method developed for sorghum, wheat and soybean. The technique involves the electrical conductance, measurement of electrolyte leakage from the leaf pieces stressed by exposure to a solution of polyethylene glycol. The results indicated that this technique was effective to assess the drought tolerance of eight grass species and sixteen orchardgrass cultivars. The percent injury measured, however, was markedly influenced by age of the leaf, sampling part of the leaf, degree of drought hardening and sampling time of seasons. Therefore, these factors should be taken into consideration at the measurement.
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G.S. PREMACHANDRA, Tohru SHIMADA
Article type: Article
1987 Volume 33 Issue 2 Pages
149-156
Published: July 31, 1987
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Effectiveness of the polyethylene glycol (PEG) test of measuring cell membrane stability (CMS) for selecting drought tolerant genotypes in orchardgrass (Dactylis gromerata L.) was investigated. The PEG test was compared with two other tests. Genetic variability of CMS was also investigated. Drought was induced artificially in pot-grown plants and in excised-leaves, and % injury in leaf tissues by drought stress was measured to compare with that in PEG test. Percent injury in leaf tissues of pot-grown plants in 12 orchardgrass cultivars was not correlated significantly with that in the PEG test (r=0.59). However, % injury in excised-leaves was correlated well with that in the PEG test (r=0.67^*). Variances in % injury in the PEG test were significant between cultivars, plants or ramets. The magnitude of variance component estimated from mean square was the smallest in ramets which represented the environmental variation. Heritability of % injury in the PEG test was 73.0%. CMS measured by the PEG test was therefore concluded to be a promising criterion in breeding for drought tolerance.
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Akira SAWAI, Seiichi UEDA
Article type: Article
1987 Volume 33 Issue 2 Pages
157-162
Published: July 31, 1987
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Hybrid embryos of Trifolium medium L. × 4x T. pratense L. were histologically examined 3 to 21 days after pollination. The embryos of T. medium were at the globular stage on the 6th day, the heart stage with cellular endosperm on the 9th day, and the early cotyledon stage on the 12th day. The hybrid embryos reached the globular stage on the 8th day and the early heart stage on the 12th day. By the 15th day, the embryos had become vacuolate or disintegrated. The hybrid endosperm remained at the nuclear stage and was disintegrating on the 15th day. The frequenct of ovaries with viable ovules decreased from 38% on the 12th day to 5% on the 18th day. These observations indicated that the optimal period of in situ embryo development before excision for in vitro culture is 12 days after pollination.
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Mutsuyasu ITO, Shinobu NAKAYAMA, Yasuhiro TSUBOTA
Article type: Article
1987 Volume 33 Issue 2 Pages
163-174
Published: July 31, 1987
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The patterns of tillering and tiller bud development were investigated anatomically on young seedlings of orchardgrass (Dactylis glomerata L.), timothy (Phleum pratense L.), tall fescue (Festuca arundinacea Schreb.), and reed canarygrass (Phalaris arundinacea L.) that were grown under both normal (30,000lux, =NL) and reduced (6,000lux, =RL) light intensities with constant day-night temperature (22°-18℃). Regular expansion of successive leaves along the axes of main shoot and emerged primary tillers were observed in each species, according to the leaf number interval "n-3" (orchardgrass and timothy) or "n-2" (tall fescue and reed canarygrass). The visible synchronization in expansion of any corresponding leaf on main shoot and emerged tillers seemed to be the consequence of their simultaneous initiation and analogous development progressing at the subapical regions of shoots. The course of tiller bud development of grasses examined was considered to consist of two different morphogenetic phases. The first was the process from the initiation of tiller bud primordium to the completion of bud structure, and the second was the rapid elongation of the tiller bud which had just completed, though the latter phase appeared to be a little dissimilar in reed canarygrass. The basic structure as a tiller bud was generally achieved immediately after the full expansion of the subtending leaf of mother shoot in every grass examined. Then the tiller bud elongation commenced without any intermission and terminated with leaf emergence under normal daylight condition. The course of this phase was, however, inhibited so strongly under reduced daylight conditions, that the completed tiller buds ceased further growth and regular tillering was disturbed.
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Toshinori OKUDA
Article type: Article
1987 Volume 33 Issue 2 Pages
175-184
Published: July 31, 1987
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The distribution of C_3 and C_4 gaminoids was studied on the grazing grassland (semi-natural grassland) of four study sites in southwestern Japan: at Tomisaki, Mt. Kuju, Mt. Aso and Mt. Azuma, in terms of their seasonal and locational variations in abundance and in the number of species. The number of species and the total value of relative abundance for C_4 graminoids generally declined with temperature-related factors: mean annual temperature and warmth and coldness indices of the study sites decreased, while the same values for the C_3 graminoids showed the opposite trend. The distribution of both C_3 and C_4 graminoids did not relate strongly with the variations of mean annual and monthly precipitation. However, the variation of abundance, whether for C_3 or for C_4 graminoids, did show a significant correlation to the variation of mean monthly temperature, i.e., the former increased its value with an increase of mean monthly temperature while the latter declined. These facts suggest that the distribution of the C_4 graminoid is mainly influenced by temperature-related factors but not by precipitation-related factors on a broad geographical level in the semi-natural grassland of temperate rain forest regions.
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Article type: Appendix
1987 Volume 33 Issue 2 Pages
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1987 Volume 33 Issue 2 Pages
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Article type: Appendix
1987 Volume 33 Issue 2 Pages
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Article type: Appendix
1987 Volume 33 Issue 2 Pages
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Article type: Appendix
1987 Volume 33 Issue 2 Pages
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Article type: Cover
1987 Volume 33 Issue 2 Pages
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Article type: Cover
1987 Volume 33 Issue 2 Pages
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