Tiller and leaf development of napiergrass (Pennisetum purpureum) and kinggrass, the hybrid between napiergrass and pearl millet (Pennisetum typhoides), was measured under three levels of chemical fertilizer supply during the growing season. Plants were grown in 1/2000 a wagner pot by transplanting single tillers under natural conditions in 1999 and 2000. Emerged tiller number (ETN) and regrown tiller number (RTN) increased with the increase in the level of fertilization. Rate of tiller emergence (RTE), rate of leaf expansion (RLE) and individual leaf area (LA) were generally larger in 1999 than in 2000 for both grasses by the doubled level of fertilization and tended to increase at the higher nodal positions with the increase in the level of fertilization. Sum of individual leaf area (SILA) on the main shoot was positively linearly related with mean leaf area per tiller (LA/T) and LA/T was with leaf area index (LAI) at all levels of fertilization. Crude protein concentration in stem with leaf sheath was linearly related with ETN in August 1999, and individual LA was almost positively related with daily effective mean temperature. The increases in RTE, RLE and SILA were concurrent with the increase in LA/T, which wasdirectly related with that in LAI, leading to the increase in dry matter accumulation in both grasses, under the higher input of fertilization. Within the levels of fertilization examined, higher input cost of fertilization obtained higher return of dry matter at the competitive price with the commercial roughage.

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Imperata cylindrica distributed in Japan had been classified into two varieties, var.koenlgii (named Fushigechigaya) and var.genuina (named Kenashichigaya or Kawarachigaya), based on the presence or absence of hairs on node of flowering culm. But now, it is thought that there are no varieties of Imperata cylindrica in Japan, because hairs are not considered to be important character on taxonomy. Recently, we found two types of Imperata cylindrica characterized by flowering phenology. We tried to clarify whether there are morphological differences or not. There are no hairs on node of flowering culm in 31 clonal fragments of early flowering type (E-type). But, there are long white hairs on node of flowering culm in 35 clonal fragments of the late flowering type (C-type). E-type had white powder on leaf sheath, but C-type had no powder. Frequency distributions on length of prickles around leaf margin were different between two types. E-type had short prickles ranged from 0μm to 80μm and C-type had long prickles ranged from 240μm to 400μm. Sizes of prickles were quite different between two types even if considering clonal variation. It can be said there are two taxonomically groups differing in not only flowering phenology but also morphological differences. It is considered that E-type is corresponding to Kenashichigaya and C-type is corresponding to Fushigechigaya.

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Under the planting system of guineagrass (cv. Natsukaze) as a summer crop and Italian ryegrass as a winter crop, the possibility of continuous forage production by rotating Italian ryegrass and guineagrass was investigated by adopting the method of volunteer seed in guineagrass. Delayed cutting at 3 weeks after heading in summer crop of guineagrass resulted in large number of seed dispersal, which was sufficient for obtaining plant density from volunteer seed in the next spring. No-tillage after harvesting Italian ryegrass caused the germination and early growth of guineagrass, but those seedlings were strongly depressed by slow regrowth of Italian ryegrass and moreover by vigorous growth of summer weeds. Disturbance of shallow soil layer by using rota-vator after harvesting italian ryegrass was considered to be an essential management to ensure the sufficient growth of guineagrass seedling. The results of this study showed that continuous forage production by means of rotating Italian ryegrass and guineagrass by using volunteer seed guineagrass was assessed to be one of the promising methods for low cost forage production in the south western warm regions of Japan.

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Purposes of this study are to investigate the present status of public grasslands in the north Tohoku region, and to obtain basic information for establishing precise grass-land management for them. Utilization purpose, plant vegetation, soil chemical properties, and forage mineral composition were investigated for 2-4 swards in seven public grasslands. Dominant plant species were orchardgrass (Dactylis glomerata L.), timothy (Phleumpratense L.), and perennial ryegrass (Lolium perenne L.) in the meadows, while Kentucky bluegrass (Poa pratensis L.), orchardgrass, perennial ryegrass, and white clover (Tolifolium repens L.) dominated in the pastures. Average soil pH (H_2O) of the seven public grasslands was 5.15, and it appeared that soil acidification was going on in the public grasslands. However, the content of exchangeable Mg in the soils and Mg content of the forages of the grasslands examined were higher than those in the previous investigations done in 1970^<th> or 1980^<th> -90^<th>. Between the meadows and the pastures, there was no significant difference in soil chemical properties, except for organic nitrogen content in the soils. The Kentucky bluegrass-dominant swards showed lower soil pH, higher soil organic nitrogen content, and higher forage nitrogen content than the swards predominated by the other forage species. Since the Kentucky bluegrass-dominant swards were significantly older than the other swards, litter layer and root mat developed in their soil surface layer. It was considered that the organic matter accumulation on the soil surface layer affected the soil fertility of the Kentucky bluegrass-dominant swards.

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There is growing concern over food prepared from farm animals contaminated with polychlorinated dibenzo-p-dioxins (PCDDs), polychlorinated-dibenzofurans (PCDFs), and coplanar PCBs (Co-PCBs) (these chemical groups are collectively called dioxins in this paper). Our study was undertaken in order to know the fate of dioxins in silage corn during the growth. We made four experiments to clarify (1) the temporal change of dioxin concentrations with the growth of corn, (2) the influences of dioxin concentrations of soil and atmosphere to the dioxin concentrations of corn, (3) the dioxin distributions within the part of the corn, and (4) the change of dioxin concentrations of corn varieties with increase of growing day. The results were as follows. Dioxin concentration and isomer profile of silage corn were mostly influenced from atmospheric condition. The concentrations were increased with the increase of corn growing days, but they were not influenced variety of silage corn.

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Corn silage is the most common preserved cattle feed. The concentrations of dioxins that evolve in the silage during the fermentation process have been unclear. The relationship between silage fermentation and fate of dioxins was investigated. Drum silo, pouch silo and wrap silo were used in these experiments. Although all silage produced in any silos were well fermented, dioxins concentrations were not decreasedduring the silage process. From the result it is considered that the decrease of dioxins is difficult during silage fermentation.

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Twenty-three dry cows from seven dairy farms in Ibaraki prefecture were monitored for dry matter intake, nutrient intake, body condition score and blood composition during the summer of 2000. At approximately seven months after parturition, the conception rate was 17%, and five cows exceeded 200 days in non-pregnant condition. In addition, three downer cows at two farms were culled. Lower intake of crude protein and non-structural carbohydrates in comparison with nutrient requirements might have resulted in these low reproductive performances, and were likely due to the poor protein contents of hay feed and low levels of grain feeding.

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The effects of different heat treatments applied for 3 days under 80℃ and dry matter content of material on dry matter and nitrogen degradability of tropical pasture legume Phasey bean silage were examined by the rumen bag method and pepsin-pancreatin method. The two heat treatments on silage just after ensiling and before opening were conducted on silages of four dry matter contents of 20, 25, 35 and 55%. The results were as follows : 1. As the dry matter content of silages increased, the degradability of dry matter and nitrogen were decreased under both heat treatments. 2. The nitrogen in ADF increased under the heat treatment just after ensiling, as dry matter content of materials increased. 3. The ratio of degradable nitrogen in post-ruminal tracts increased with dry matter content of materials under both heat treatments.

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Two types of brewer's grains (BG), derived from high and low malt brewing, were mixed with various dry feeds (BG : beet pulp : oats hay : wheat bran : molasses=5 : 2 : 1 : 1 : 1 on a fresh weight basis), and ensiled in polyethylene bottles to prepare a total mixed ration (TMR silage). Silos were opened after 5, 20 and 40 d of storage ; the composition of soluble sugars and the profile of fermentation products were determined. Experiment was duplicated using different lots of BG (Exp. 1 & 2). Regardless of the type of BG, lactic acid production occurred and large numbers of lactic acid bacteria were found at 12 h after BG production. Principal sugars were maltose and raffinose in both BG, whilst the amount was higher in low malt type BG. When TMR silage was made, the main sugars altered to fructose, glucose and sucrose due to added feeds, and the differences in sugar contents diminished. Lactic acid (Exp. 1) or ethanol (Exp. 2) was the major fermentation product in TMR silage, and this property was not influenced by the type of BG used. Mannitol accumulated in lactate silages as storage prolonged, indicating that heterolactic fermentation was enhanced even when lactate silage was obtained. Accelerated ethanol production was found in ethanol silage from the beginning of storage ; the highest content (75gkg^<-1> DM) was given in TMR silage prepared with low malt type BG. Propionic and butyric acids were almost undetectable and ammonia N accounted for less than 60gkg^<-1> N in any of the silages, suggesting that TMR silage can be considered "well preserved" regardless of lactate and ethanol fermentation. Significant differences due to high and low malt type BG were found in the fermentation of TMR silage ; however, the production lot had much greater effects in the two experiments.

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Studies were carried out in the central highland area of Kyushu to observe the germination of Da (Digitaria adscendens (H.B.K.) Henr.) and EC (Echinochloa crus-galli (L.) Beauv.) as influenced by vegetation and cutting management. We made three-treatments plots using containers ; the plot without plant (bare ground plot), the plot planted with stubbles ofDactylis glomerata L. with cutting two times on July 4. and Aug. 15. (cutting plot) and without cutting (no cutting plot). The number of seedlings of both species and relative light intensity on the soil surface were investigated every two weeks from May 9. to Sep. 12. At the end of the experiment, the number of germinable buried seeds were counted. The soil surface temperature was measured during 3 days before and after each cutting. The total number of seedlings during the experimental period was in the order of the bare ground plot>the cutting plot>the no cutting plot. In the bare ground plot, the largest number of seedling was observed in the middle of June for Da and from the end of May to the middle of June for EC. In the cutting plot, many seedlings were observed in both species during the first two weeks following cutting. Intensive germinations were not observed in both species in no cutting plot. The number of germinable buried seeds of both species at the end of the experiment in the no cutting plot was significantly (p<0.05) larger than that of the cutting plot and the bare ground plot where no germinable buried seeds were found. It was considered that the increase in relative light intensity and the widened diurnal range of surface soil temperature after cutting induced the germinations in both species.

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Brown-midrib mutants (bm or bmr) existed in maize (Zea mays L), sorghum (Sorghum bicolor (L) Moench) and pearl millet (Pennisetum americanum (L.) Leeke), which have been reported to have significantly, lower lignin contents than their normal plants, and they have inherently high digestibility. In this study, we conducted to investigate for accumulation of lignin according to developmental stages in brown-midrib-6 (bmr-6) mutant comparing with its original normal-6 (N-6) line of sorghum. Lignin content determined by the acetyl bromide method was lower in bmr-6 than in N-6 during the developmental stages. In contrast, lignin content determined by the phloroglucinol-HCl assay, which detects aldehyde groups, was higher in bmr-6 than in N-6. Enzyme activities of PAL (phenylalanin ammonialyase), CAD (cinnamyl alcohol dehydrogenase) and POD (peroxidase), involved in phenylpropanoid pathway, were measured in N-6 and bmr-6 during the developmental stages. Bmr-6 had severely deficient in PAL activity at 50-day-old after seeding, with only 40% of the activity found in N-6. CAD activity of bmr-6 was also depressed during 50 to 90-days-old. POD activity was increased equally in N-6 and bmr-6 until 70-days-old, but the activity in bmr-6 was significantly low after 80-days-old comparing with N-6. These results suggested that bmr-6 mutant of sorghum was caused by a number of enzymes deficiency in the phenylpropanoid pathway.

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Reed canarygrass (Phalaris arundinacea L.) clones, collected from domestic grasslands and random selected from the cultivar 'Palaton', were surveyed on their morphological traits and chemical components. To estimate for the plant type indexes on both the first and the second cutting stages, data on the panicle length, internode length, leaflet length, and leaflet width were integrated using the principal component analysis (PCA). The plant type index at the first cutting stage was expressed by two main factors. The first factor indicates the total size, i.e., the 'Size factor,' and the second one represents the difference of the sizes between culm and leaf. The relationships between the plant type index and three chemical components (the ash, organic cellular content and magnesium content) were observed, mainly because the cellular contents are affected by the plant size and the organ specificity. At the second cutting stage, both the 'Culm' and 'Leaf factors for expressing the plant type index, which were independent from each other, differed from the factors of the first cutting stage, were related to the lodging resistance. It is a possibility that the improvement of the chemical component and the lodging resistance could be carried out by using the plant type indexes at each growing stage.

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Clonal plant species demonstrate fundamental particularities in the framework of established concepts of population biology. A deep understanding of these general properties of clonal plant species is extremely helpful for gaining insight into their surprisingly strong adaptive capacities in the whole biosphere. Relating to the effect of physiological integration, this paper summarized and discussed six relatively important aspects of these particularities, i.e., 1) the greater potential capacity of competition and colonization, 2) the adaptation to disturbance, stress and heterogeneity, 3) integration and timely independence of ramets as a powerful strategy in unpredictable environments, 4) risk spreading among independent ramets, 5) the division of labor among independentramets, and 6) the intraclonal shoot size variations and the effect of self-thinning.

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