Spatial pattern of live-shoot biomass of individual plant species was observed in two sown grasslands differing in their species composition to clarify the relationships between dominance and spatial heterogeneity of each species. Three surveys were carried out. In each survey, one hundred 50 cm×50 cm quadrats were arranged along a straight-line 50m long in a grassland, and the plants within each quadrat were harvested at a height of 3cm above the ground surface. The harvested samples were separated into live shoots based on species and whole dead shoots to measure the dry weight. The spatial heterogeneity of the respective materials was evaluated using p, one of the parameters of gamma distribution. The main results were as follows: (1) the live-shoot biomass of most species was distributed spatially more heterogeneously than in a random expectation, and the only two most dominant species exhibited a low heterogeneous pattern ;(2) Spatial heterogeneity for individual species showed a strong negative correlation with the degree of dominance; and (3) The total aboveground biomass, total live-shoot biomass and dead-shoot biomass showed a less heterogeneous pattern than in a random case although the live-shoot biomass of each species exhibited a strong heterogeneous pattern.

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To clarify the potential productivity and ecological characteristics of vegetation dominated by Stipa baicalensis, the aboveground phytomass, its seasonal dynamics, and vegetative composition were investigated in an ungrazed and unmown S. baicalensis-Prunus sibirica community as the native climax vegetation of the Songhen plain of Northeast China. The plant community was composed of 64 species. The maximum aboveground live phytomass of the community was 222.8 g DM m^<-2> at 130 days after starting growth (i. e., Aug. 18), after which the phytomass decreased. The dynamics can be described by an extended logistic model. The estimated crop growth rate (CGR) reached its maximum (3.9 g DM m^<-2> day^<-1> ) at 66 days after starting growth (i. e., June 15). Then the CGR decreased from that level, and showed a minus value from approximately 125 days after starting growth (i.e., Aug. 13). S. baicalensis constituted 26-36% of the community and was the most productive species among the components. P. sibirica amounted to 13 to 18%. The remaining production was primarily made up of Cleistogenes species, the other grasses, and Carex species. The Carex species was the earliest of the components to reach the maximum CGR.

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Ferulate ethers and lignin in straw of barley (Hordeum vulgate L.) cultivars and stalk of sorghum (Sorghum bicolor Moench) with different maturity were determined to relate to dry matter degradability (DMD) and proportion of arabinose residues carrying alkali-labile substituents at position O-5. The susceptibility of botanical fractions and fractionated specific tissue cell walls of barley straw to degradation by rumen microorganisms and enzymes was also related to ferulate ethers and lignin. The content of ferulate ethers in barley straw and sorghum stalk was inversely related to DMD and positively to the proportion of alkali-labile substitution of 0-5 arabinose residues. The phenolic contents of whole straw were largely determined by phenolic contents of the stem fraction. The phenolic components recognizable in the stem fraction were also more influenced by the composition of the fibrous cell walls than that of the parenchyma cell walls. The DMD of such botanical fractions was also mostly responsible to the contents of ferulate ethers and lignin, although the susceptibility of specific cell was unclear.

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Thirteen species in 3 genera of dung beetles (Scarabaidae), Aphodius rectus, A. sordidus, A. languidulus, A. pusillus, A. haroldianus, A nigerrimus, A. haemorrhoidalis, A brachysomus, A. rygosostriatus, A. pratenisis, A. sublimbatus, Caccobius jessoensis and Liatongus phanaeoides, were collected from cattle dung in grazing pastures at 8 sites in the Tokachi district in eastern Hokkaido in 1977. The sites chosen were Obihiro, Tokachi-Shimizu, Shihoro, Sarabetsu, Hiroo, Obitomi, Tokachi-Chokubetsu and Ashoro. Number of species in collected beetles increased in proportion as the mean temperature (from May to October) of the sites was high. Based on the results of seasonal prevalence in Obihiro in 1979, 1980, 1981, 1988 and 1993, besides the fact that the numbers of A. brachysomus, a dominant species in western Hokkaido, were low in the Tokachi district, the species composition and seasonal prevalence of the dung beetles collected in these two regions were not significantly different. On the other hand, many differences were found between the species composition and seasonal prevalence of dung beetles collected in the above-mentioned regions and those collected in the middle and southwest areas of Japan. In Tokachi district, A. rectus, A. sordidus, and A. pusillus were regarded as main dwellers and A. haroldianus and C. jessoensis as main tunnelers. Seasonal prevalence of dung beetles in Tokachi district was divided into the following three types: uni-voltine type, A. sordidus, A. haroldianus, A. heamorrhoidalis, A. pratenisis, A. sublinbatus and L. phanaeoides; bi-voltine type, A. rectus and A. pusillus, and an all-season type, C. jessoensis.

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Yield trials of three guineagrass cultivars ('Natsukaze', 'Natsuyutaka' and 'Gatton'), three experimental lines ('Kyushu No. 3', 'Tift PM39' and 'Tilt PM 41'), one green panic cultivar ('Petrie') and two rhodesgrass cultivars ('Katambora' and 'Hatsunatsu') were conducted on Ishigaki Island, Okinawa Prefecture, Japan. Among them, 'Natsuyutaka' was most promising of the guineagrass cultivars and lines studied for both 3 years and 7 years because it is extremely productive and drought tolerant. 'Tift PM39' and 'Gatton' also showed promise based on their productivity and persistence. 'Kyushu No. 3' would be well suited to grazing because of its winter productivity and regrowth. Although 'Natsukaze' gave the highest dry matter yield in the first year, it was less persistent than the other cultivars. Two rhodesgrass cultivars and 'Petrie' green panic were less persistent than the guineagrasses. Flowering patterns suggest that 'Natsukaze', 'Natsuyutaka' and 'Katambora' may be more sensitive to photoperiod than the other cultivars and lines. 'Natsuyutaka' and other guineagrass cultivars could be used for overseeding or reestablishment of degraded rhodesgrass pastures in Okinawa. It will be very difficult to obtain a large amount of 'Natsuyutaka' seed on Ishigaki Island because it produces fewer seed heads than the other cultivars and lines, and flowers strongly during the wet September to January period.

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Variation within and among tetraploid cultivars of rhodesgrass was assesed based on AFLP analysis. Genomic DNA of 69 individual plants representing 5 tetraploid cultivars was analysed by AFLP using 4 EcoRI and MseI selective primer pairs with three additional nucleotides. Of all the 227 bands obtained from these 4 primer pairs, 92.5% were polymorphic across the cultivars analysed, indicating a high level of genetic variability at the DNA level in these cultivars. The dendrogram showed between 58 and 85% genetic similarity among all the individual plants analysed. The analysis permitted the unique identification of each individual and the cultivars were sufficiently different to form separate clusters. The cultivar "Callide" was distantly related to all the other cultivars as expected based on differences in the morphoagronomic traits between them. A high level of intracultivar variation was present in all the cultivars used in this study with CV. "Callide" being the most diverse and cv. "Pokot" the least diverse. The results of this study show that AFLP analysis can be an efficient technique for the genetic characterization of rhodesgrass cnltivars with potential applications for breeding purposes.

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The lodging resistance and dry matter yield of dent corn in a no-tillage system was compared with those in a tillage system under different planting densities and application rates of nitrogen fertilizer. 1. Dry matter yields of dent corn in the no-tillage system were the same as or more than those in the tillage system. Yields in both dense planting plots and larger N fertilizer plots were higher than those in the conventional planting density and normal N application plots. 2. The ratio of plant broken by a typhoon attack was lower in the no-tillage plots than the tillage plots due to the larger supporting strength of no-tilled soil. A higher degree of lodging was observed in the dense planting plots relative to the normal density plots. A heavy N application suppressed the degree of lodging. 3. The value of horizontal pulling resistance indicated that the lodging resistance of dent corn was higher in the no-tillage plots than in the tillage plots. Since the no-tillage system decreases the extent of lodging relative to the tillage system even under dense planting conditions, no-tillage cultivation with a higher plant density can increase the dry matter yield of dent corn with suppressed lodging.

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Two experiments were carried out to study the effects of characteristics of feed and animal condition on voluntary intake. The voluntary feed intake was measured as dry matter intake (DMI) with four dairy cows fed rapping roll-bale Silage of four Italian ryegrass (IRGS) ad libitum. The digestibility of dry matter (DM) and organic cell wall (OCW), and the rate of degradation of OCW in the rumen of the IRGS were determined using in vitro method. Mean of DMI per day and DMI per metabolic body weight of four IRGS ranged from 6.3 to 9.4 kg/day, from 54.2 to 79.8 g/kg^<0.75>, respectively. The DMI per day of IRGS in dairy cows was highly correlated with OCW, low digestible fraction of OCW (organic b fraction : Ob), sum of organic cellular contents (OCC) and high digestible fraction of OCW (organic a fraction : Oa) (OCC+Oa), neutral detergent fiber (NDF) and acid detergent lignin (ADL). The DMI per day can be predicted from the following equations; DMI =-0.257×OCW +23.69 (r=0.987), DMI=-0.162×Ob+16.34 (r=0.995), DMI= 0.214×(OCC+0a)-0.34 (r= 0.995), DMI =-0.258×NDF+23.35 (r=0.996), DMI =-1.047×ADL+13.96 (r=1.000). In addition, the DMI per day of IRGS in dairy cows was highly corrlated with retention time in the rumen, digestibility of each chemical compositions and the rate of degradation of fiber in the rumen. Similar values were observed in DMI per metabolic body weight. From those results, it was cleared that each factor examined in this study affets on voluntary feed intake.

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To determine improvement of voluntary intake of wheat straw with steam treatment, wheat straw was pressurized at 12 kg/cm^2 and steamed for 5 or 10 min. Digestion trials for measuring voluntary intake, digestibility and reticuloruminal retention time, degree of filling in total tract were conducted using wethers. Wheat straw was fed together with soybean meal (4 g/kgBW). Steam treatment improved neutral detergent fiber digestibility, however it lowered nitrogen digestibility. Voluntary intake of wheat straw steamed for 10 min. was higher than those of others. TDN content was improved by steam treatment for 5 min., on the other hand, amount of TDN intake increased with 10 min. of steam treatment. The higher TDN intake was mainly due to higher voluntary intake of steamed wheat straw. The degree of filling in total tract with feeding straw steamed for 10 min. was also higher than that with feeding of untreated straw. Reticulo-ruminal retention time with feeding of steamed straw was shorter than that of untreated straw. Moreover, the steam treatment for 10 min. tended to increase stuffed bulk density and grinding ability by cutting mill. The steam treatment for 10 min. accelerated the degradation of wheat straw in mastication and rumination. Consequently, higher voluntary intake was achieved.

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Two species of basidiomycetes, Pleurotus salmoneostramineus and Aaricularia polytricha, were incubated in bagasse culture for 60 days without fruiting of the mushroom, and the effects on the improvement of rumen degradability of the cell walls of bagasse were then examined. Observations from scanning (SEM) and transmission (TEM) electron microscopy, and from ultraviolet microspectrometry, were also conducted from samples before and after treatment with basidiomycetes. Variations in the mode of bagasse cell wall degradation were then related to the enzymic activities of β-glucosidase, carboxymethyl cellulase, xylanase, and peroxidase in the two species of basidiomycetes incubated for 18 days in a submerged culture. Pleurotus salmoneostramineus, possessing higher fiber-degrading activities in cell-associated enzymes, was observed to penetrate and degrade the cell walls of bagasse. In contrast, Auricularia polytricha, possessing higher fiber- degrading activities of cell-free enzymes, was observed to degrade bagasse cell walls apart from the hypha of basidiomycetes, as shown in KMnO_4- and PATAg-stained TEM photographs. These data were discussed in relation to the effects on the decomposition and rumen degradability of cell wall constituents in bagasse.

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It is well-known that voluntary feed intake of tall fescue (Festuca arundinacea Schreb.) is poorer than that of ryegrasses. Intake of forage is often limited by the resistance of plant tissues to breakdown and the amount of fiber present in plant tissues. This study was carried out to search the anatomical characters related physical strength of leaf blades in tall fescue in the three experiments described bellows. In the first experiment, physical strength by wet-sieves and anatomical characters of tall fescue were compared with those of Italian ryegrass showing good voluntary intake. The leaf blades of tall fescue were harder to breakdown to particle and higher proportion of vascular bundle having bundle sheath extension than those of Italian ryegrass. In the second experiment, each three clones from 2 groups of tall fescue selected toward low (LS) and high (HS) physical strength were grown in a field. Transverse section of three leaf blades at three leaf positions was made and observed for each three clones respectively. The porportion of vascular bundle having abaxial bundle sheath extension was significantly lower in LS than HS at all positions. There was no significant difference in the proportion of large vascular bundles and vascular bundles having sclerenchyma between LS and HS at all positions. In the third experiment, the progeny from these clones was evaluated. There were significant differences in physical strength and proportion of having abaxial bundle sheath extension between progenies of LS and those of HS. It is possible to decrease the frequency of abaxial bundle sheath extension for the improvement of physical strength in tall fescue.

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The effect of silage fermentation on activity of Mycobacterium avium sub sp. Paratuberculosis was studied using small scale fermentation system. M. avium sub sp. paratuberculosis was added to milled and sterilized alfalfa hay with 80% (w/v) sterilized isotonic saline, and lactic acid bacteria or formic acid were used as additives for the silage preparation. When stored at 5℃ for 14 days, all of the silage were poor preserved, with high pH value and low lactic acid content. The counts of M. avium sub sp. paratuberculosis were high in these silages. When stored at 30℃ or 37℃ for 14 days, all of the silages were well preserved, with low pH value and high lactic acid content. The counts of M. avium sub sp. paratuberculosis decreased at a level that was not detectable. The tolerance of M. avium sub sp. paratuberculosis to formic acid, lactic acid, acetic acid, propionic acid and butyric acid were 0.05, 0.10, 0.05, 0.10 and 0.30%(w/v), respectively. After 7 days of incubation with 0.50% organic acid solution, cell form of that bacteria was changed. However, M. avium sub sp. paratuberculosis showed activity in these organic acid solutions those were adjusted using 30%(w/v) NaOH to pH 6.5. The results confirmed that the fermentation products of silage effectively inhibit the survival of M. avium sub sp. paratuberculosis, and the well-preserved silage could not become a resource of Jhones' disease. However, that in the poor-fermented silages with high pH value and low lactic acid content could become a resource of that disease.

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