A simulation approach was made to evaluate management decisions for grassland-based beef production (growing cattle) systems in the low-altitude region of Kyushu. Two hundred scenarios which differed in land use, animal density (AD, 2-10 head/ha), target liveweight gain (TLWG, 0.2-0.8kg/head/day) and sex of animals (steers and heifers) were tested using data from a case farm. The land was utilized as a forage crop field (FCF), a permanent pasture (PP) or their mixture. A variety of agroecological and economic criteria were used for evaluation. As an example of the quest for optimal management for a given goal, scenarios for a sustainable system were searched for. Three scenarios were finally selected as most appropriate, but they were not regarded as sustainable because of their high potential N impact on the environment. The similar management options among the 3 scenarios (proportion of FCF area=0.5-0.75, AD=6 head/ha, TLWG=0.4kg/head/day) reflected the trade-off between the FCF and PP, and this was considered to be one of the central issues in many grasslandbased animal production systems of the region.

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In this study, we intend to establish a new durable reseeding method of herbage seeds by sheep defecation in the Inner Mongolian steppe. 1. Factors affecting germination from dung pellets Two sheep were fed 200g alfalfa seeds and were grazed for 36 hours. On the plowed field with soft soil surface, 45% dung pellets were partially covered with soil and 22% dung pellets were completely buried under the ground by trampling. Seventy nine to 86.9% of all dung pellets collected included about two grains of seed per pellet. The number of seedlings was 518/100m^2 in the plowed field. These seedlings emerged from seeds within dung pellets which were embedded 1cm depth under ground. 2. Evaluation of the dung pellets as a water retention material As the dung contained 18% to 22% water, the water content of seed, contained in the dung pellets, increased from 31% to 68%. The relationship between the water contents of dung pellet and that of seed showed positive correlation. It was found that water in the dung pellets increased the water content of the seed in the dung pellet. Water content of dung pellets which were buried in the soil increased soil water level rapidly during the first 12 hours. As the dung pellets were buried in the wetter soil, the dung pellets were capable of absorbing about 2.2 times water and keeping this water for few days after absorption.

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Calamagrostis longiseta, C. langsdorffii and C. hakonensis are perennial C_3 grasses and usually occur in cool habitats. In the Kirigamine grassland of central Japan, the distribution of these three species is limited to altitudes higher than 1,650m a.s.l.. The objective of the present study was to clarify the temperature optima and the upper temperature limits for vegetative and reproductive growth of these species, and to examine whether these species are physiologically restricted to higher altitudes. We chose four sites with altitudes of 14,600, 1,342 and 1,712 m a.s.l. to provide an altitudinal gradient, collected these Calamagrostis species from subalpine grasslands, and grew them at sites on the gradient. Pot experiments conducted from 1993 to 1995 showed similar patterns of growth response to the gradient in the three species, although the dry matter yield was different. These species possess a certain degree of acclimation capacity to higher temperatures. Overall, however, the results showed clearly that the three species preferred medium altitudes (600 to 1,342m), where the plants could attain higher total biomass, height and total number of tillers, leading to success in reproductive growth. Plants could succeed in vegetative and reproductive growth at high altitude (1,712m), but total biomass was least here due to the short growing period. Vegetative growth of plants at low altitude (14m) could take place during the relatively cool period from spring to early summer, but marked declines occurred in net photosynthesis and aboveground green biomass during the following hot summer. In addition, the plants grown at low altitude appeared unable to flower, and the results suggest that the warm winter combined with the subsequent rapid rise in temperature may limit the reproductive growth of these Calamagrostis species. These results suggest that the optimal temperature for the growth of these three grasses may occur at medium altitudes within the selected gradient, and range between 6.8℃ and 10.4℃ if it is described by the annual mean temperature of the three experimental years. Moreover, if there is a lack of competition from neighbors, and temperature is the only important factor determining growth, then these three species prefer medium altitudes for their growth rather than high altitude where temperature conditions are mostly similar to the Kirigamine grassland, and the upper temperature limits for their growth occur only at extremely low altitudes. We therefore suggest that the growth of these Calamagrostis species is probably not physiologically limited by warmer temperatures at lower altitudes (1,500-1,650m) in the Kirigamine grassland.

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To investigate the ruminal characteristics under grazing white clover, three fistulated Suffolk and Corriedale crossbred wether sheep (mean body weight 48.0kg) were kept in metabolic cages, and foam stability of ruminal fluid, volatile fatty acid (VFA) and ammonia-nitrogen (NH_3-N) concentrations, protozoal density and ruminal contraction were measured with the course of time after feeding fresh white clover (Trifolium repens L.) or orchardgrass (Dactilis glomerata L.) at the same level of dry matter intake (30g dry matter/kg body weight/day). The foam stability of ruminal fluid was markedly high in 2hr after feeding of white clover compared with orchardgrass. Total VFA, acetate, propionate (P<0.05) and NH_3-N (P<0.001) of ruminal fluid in 2, 4, 6hr after feeding were significantly higher in white clover than in orchardgrass. The frequencies and amplitudes of ruminal contraction were greater and slightly smaller, respectively, in white clover feeding than in orchardgrass feeding. Ruminal properties such as foam stability of ruminal fluid, ruminal fermentation and ruminal motility in white clover feeding were largely different from those in orchardgrass feeding in both respects of the level and the changing pattern with the course of time after feeding.

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Lactic acid productivity and growth of Lactobacillus rhamnosus NGRI 0110, Lactobacillus pentosus NGRI 0506 and Lactobacillus plantarum NGRI 0320 and NGRI 0529 were examined in a model system for ensilage using of milled alfalfa hay cube added with water (AHC medium). In the pure culture, L. rhamnosus produced larger amounts of lactic acid at 37℃ and 45℃ in spite of slower growth than L. plantarum and L. pentosus, whereas later strains produced larger amounts of lactic acid at 10℃ and 5℃ than L. rhamnosus. In the mixed culture with a butyric acid bacterium (Clostridium butyricum) and a coli-form bacterium (Klebsiella pneumoniae), L. rhamnosus inoculated together with L. plantarum or L. pentosus improved fermentation quality at 37℃ more effectively than that inoculated each alone. The mixed inoculation of these strains of the genus Lactobacillus was also effective for improving fermentation quality in the ensiling process of Italian ryegrass.

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For elucidation of involvement of bioactive substances in the induction of phleinase in defoliated stem bases of orchardgrass, the effect of exogenously applied substances on the enzyme activity was studied. The induction of phleinase in excised, defoliated and undefoliated stem bases was enhanced by treatment with gibberellic acid, cytokinin, 8-bromoadenosine-3, 5-cyclic monophosphate (8-bromo-CAMP) or theophylline, while not affected by indoleacetic acid, 2, 3, 5-triiodobenzoic acid or 2-chloroethylphosphonic acid. The phleinase induction was suppressed by continuous treatment with abscisic acid (ABA) to excised stems, but not by transient treatment with ABA at defoliation. These results suggest that there is a possibility of involvement of the changes in endogenous concentration of gibberellin, cytokinin, CAMP and ABA in the phleinase induction in the stem bases of orchardgrass after defoliation.

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The effect of environmental temperature on cell membrane stability (CMS) and solute accumulation in orchardgrass (Dactylis glomerata L. cv. Aberystwyth S 143) was studied in pot culture grown plants. The plants were subjected to three temperature treatments (25/20℃; 20/15℃; 15/10℃ day/night temperatures). Leaves were sampled 14 and 42 days after the commencement of the treatments. CMS was evaluated by the polyethylene glycol technique and subsequent measurement of electrolyte leakage. Osmotic potential and solute concentration in extracted leaf sap were measured. With decreasing temperature, CMS increased and osmotic potential decreased. Water soluble carbohydrates concentration in cell sap increased and K^+ concentration decreased with decreasing temperature, however, changes in concentrations of amino acid, organic acid, Ca^<2+>, Mg^<2+>, Na^+, SO_4^<2-> and C1^- were not observed. Water soluble carbohydrates and K^+ were the primary osmotic contributors in orchardgrass. Potassium played a major role in increasing osmotic concentration in plants under high temperatures, while plants exposed to low temperatures accumulated more water soluble carbohydrates, developed lower osmotic potential and maintained higher turgor. Water soluble carbohydrates concentration correlated positively with membrane stability.

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Eleven species or subspecies of Medicago widely distributed in the world were evaluated in association with six strains of R. meliloti, isolated from nodules of six Medicago species. Significant differences in acetylene reduction ability and in plant dry matter among Medicago species were recognized, indicating considerable genetic variation in the symbiotic nitrogen fixation among species in the genus of Medicago. Perennial species M. sativa ssp. sativa and M. sativa ssp. falcata produced effective nodules to all of the six strains of R. meliloti, but annual species M. rigidula, M. arabica, M. aculeata and M. rugosa were effective to only four strains, suggesting that the latter was more specific to strains of R. meliloti in nitrogen fixation than the former. The six strains of R. meliloti isolated from six species of Medicago have differentiated in the compatibility with the plant species; GU 94-1, GU 95-1 and GU 96-1 were more specific to host plant species than the other three strains. The highest acetylene reduction ability and plant dry matter was obtained when a strain of R. meliloti was inoculated to the Medicago species from which the strain was isolated, indicating that the best compatibility was in the combination of the strain of R. meliloti with the species from which the strain was isolated. It can be estimated that the host plant produced very effective large nodules when associating symbiotically with the strain of R. meliloti which has the best compatibility. We can conjecture that it is the start which leads to coevolution of R. meliloti with Medicago species.

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Seeds of Trifolium repens with a wide variation in their hardseededness were placed into the rumen of a fistulated steer in nylon bags to investigate the population dynamics in the rumen. After the seeds were retained in the rumen for 0 (control), 1, 2, 3, 7, 14 days, and then germination tests were carried out over 42 days at 20℃ on all the seed recovered from the nylon bags. The seeds were classified into 4 groups as follows. Hard seeds (H) were defined as seeds which remained intact and ungerminated after the 42 days (germination test). In germination test for control, short-term soft seeds (SS) were defined as seeds which germinated within the germination peak during the first 7 days, long-term soft seeds (SL) as seeds which germinated between 8 and 42 days (after the germination peak), and dead seeds (D) as the remainder. According to the characteristic pattern of the change in soft seeds for the first day in the rumen, SS would be equivalent to the seeds which changed into D within 1 day in the rumen, and SL would be equivalent to the seeds which were viable and germinateble when recovered from a rumen. The model of the seed population dynamics in the rumen was constructed with simultaneous differential equations as follows. dH/dt=-k_1 H, dSL/dt=k_1 H-k_2 SL, dSS/dt=k_2 SL-k_3 SS, dD/dt=k_3SS Values of the parameters were estimated, and predictions from the model closely agreed with the data from the experiment. The long-term soft seeds (SL) that possess some degrees of characteristic of hard seeds are likely to contribute to seed dispersal via ruminants and to germination and establishment on dung pats. There seems to be a close correlation between the distribution of germination rate in the germination test on seeds before placement in the rumen and that of death rate of seeds in the rumen.

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Using first cutting alfalfa (Medicago sativa L., blooming) and timothy (Phleum pratense L., heading), silage was prepared by adding the following percentages of cellulase derived from Acremonium cellulolyticus Y-94 (cellulase): 0, 0.005, 0.01, and 0.02% to alfalfa, and 0, 0.006, 0.012 and 0.024% to timothy. The quality of alfalfa silage was improved due to two factors: the addition of cellulase caused the production of butyric acid to stop, and as the percentage of cellulase increased, the pH and NH_3-N% in the total nitrogen decreased and the content of lactic acid increased. But the addition of cellulase significantly decreased the recovery of dry matter. On the other hand, the quality of timothy silage was also improved due to the absence of butyric acid. The quality of both silages were high with 0.006% and 0.012% additions of cellulase, but low with 0.024%. The addition of cellulase significantly decreased the content of neutral detergent fiber (NDF) and acid detergent fiber (ADF), and as the rate of cellulase addition increased, the content of NDF and ADF decreased further. On the other hand, the water-soluble carbohydrate (WSC) content significantly increased with the addition of cellulase, and as the rate of cellulase addition increased, the content of WSC further increased. The breakdown of the hemicellulose was not affected by cellulase addition. These results show that an addition of cellulase in the range of 0.005%-0.012% is the best for improving the fermentation quality of silage. More addition of cellulase does not produce favorable results.

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Guineagrass (Panicum maximum Jacq.) was ensiled into a laboratory bag silo for the investigation of the degradation of cell wall constituents during silage fermentation. The resultant silage was "acetic acid silage" with high pH and low lactic acid content. The most of ADF, lignin and cellulose of guineagrass were recovered from the silage, but parts of NDF and hemicellulose had disappeared. This indicates that cell wall decomposition occurred mostly in the hemicellulose fraction. The recovery of hemicellulose-derived monosaccharides from the silage was low for glucose and galactose, but was high for xylose and uronic acids. About 20% of dry matter and 30% of digestible dry matter (in vitro) had disappeared. It is suggested that hemicellulose fermentation plays an important role in ensiling of tropical grasses.

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Percent Brix of stalk juice and Sugar Index which is corrected percent Brix by the stalk dry matter percentage, were determined to investigate the relation with organic cellular contents (OCC), organic a fraction (Oa), and organic b fraction (Ob) and to develop the simple method of estimating the dry matter digestibility of forage maize (Zea mays L.). Both indices were highly and positively correlated with OCC and OCC+Oa contents, showing higher correlations in Sugar Index, which indicated that there was an effect of correction by stalk dry matter percentage. It was concluded that percent Brix was available enough to estimate the dry matter digestibility of forage maize and Sugar Index was more reliable than percent Brix. We propose Sugar Index for the estimation of dry matter digestibility irrespective of being more laborious than percent Brix and it would be usable to select the genotypes with high digestibility, which have high OCC content.

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There has been need for a precise technique for evaluating root lodging resistance in maize breeding, because natural lodging is accidental and unreliable. The present study was conducted to develop a new method for evaluating root lodging resistance of maize by measurement of horizontal pulling resistance. Ten inbreds selected for root lodging resistance in the previous experiments, 44 single cross hybrids among them and three commercial hybrids were used and their horizontal pulling resistance was determined about 20 days after silking. Since root lodging resistance is closely related to root strength and plant size, horizontal pulling resistance-value (HPR-value) was calculated using the following formula. [numerical formula] Two years mean of HPR-value and that of discriminant function value of root lodging resistance (DF-value) by ISHIGE et al. (1983) were compared for correlation with the three years mean of rate of root lodged plants. The correlation coefficients of HPR-value (r=0.631 in hybrids, r=0.564 in inbreds) were higher than those of DF-value (r=0.277 in hybrids, r=0.382 in inbreds). However, the correlations were not significant in inbreds. The results indicated that HPR-value is non-destructively measurable and efficient for quantitative evaluation of root lodging resistance of hybrids.

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Fibrous, degradable and physical characters in 14 varieties of orchardgrass (Dactylis glomerata L.) were evaluated for 4 years in connection with the study on their palatability measured by Holstein heifers. Relationship between these characters in varieties and their palatability were investigated throughout the growing seasons. NDF and ADF content were negatively correlated with palatability at the heading stage in spring and at the regrowth in summer, respectively. As for degradable characters, cellulase degradability (a+b), instantly soluble fraction (a), insoluble but potentially degradable fraction (b) and the rate constant (c) of degradable fraction were determined by the φRSKOV'S equation: Y=a+b (1-e^<-ct>), respectively. Significant correlation coefficients between these degradable characters and palatability were not obtained throughout the growing seasons; it indicates that breeding for the improvement of both palatability and degradability and/or degradable characters in orchardgrass might be possible. As for physical characters, such as leaf tension and compression load, grinding energy and viscoelastic parameters were related with degradability in seasonal changes. But on the whole, they were not significantly correlated with palatability.

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Concentration of 9 mineral elements and 3 constituents of free sugars in 14 varieties of orchardgrass (Dactylis glomerata L.) were evaluated for 4 years in connection with the study on their palatability measured by Holstein heifers. Significant differences were recognized between varieties, especially in N, P, Mg, Ca, Mn and total free sugars. Relationship between palatability of varieties and their chemical constituents were investigated throughout the growing seasons. In late summer, the concentration of Ca was positively correlated with palatability and the ratio of K/(Ca+Mg) was negatively correlated with palatability in 1992, respectively. The concentration of K was also positively correlated with palatability in 1993. In autumn, the concentration of P was positively correlated with palatability in 1991. But there was no relationship between palatability of varieties and their sucrose, glucose and fructose concentration at the vegetative stage, respectively. Palatable variety Lude showed the highest concentration of Ca and ratio of Ca/P among the tested varieties, and also showed the lowest ratio of K/(Ca+Mg) throughout the growing seasons. It indicates that Lude will be a useful breeding material for the improvement of both palatability and the concentration and the ratio of mineral elements. A volatile compound which was specifically found in Lude and Lully was briefly discussed in relation with palatability.

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Difference among sorghum cultivars (Sorghum bicolor Moench, Sorghum bicolor Moench×Sorghum sudanense (Piper) Stapf) of nitrate nitrogen concentration under a large amount application of nitrogen fertilizer was investigated. The cultivars tested were NS-V, BR48 (grain type), P956 (dual purpose type), FS305, FS902 (sorgo type) and SS901 (Sudangrass types). After late internode elongation stage, the following equation could be used in all cultivars; [nitrate nitrogen concentration based on dry matter]≒[nitrate nitrogen concentration of stem based on fresh weight]×[the ratio of stem based on dry matter per the ratio of dry matter of stem]. Nitrate nitrogen concentration of FS 305 was drastically decreased after flowering stage. The decrease was analyzed by using above the equation, and it was due to the decrease of the ability to accumulate nitrate nitrogen in stem.

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In this study, we attempted to monitor the changes in the type of grassland use and advancement of grass mowing utilizing satellite data. On the satellite images acquired during the growing seasons, grasslands just after mowing showed the distinctive reflectance characteristics. Using these characteristics, we analyzed the changes in grassland-use and advancement of pasture mowing on Konsen plain, Hokkaido during a decade. This analysis clarified that of grasslands area for grazing decreased, and mowing time became earlier in the study site. Ground survey of the study site supported the result of satellite monitoring. These results prove the usefulness of satellite remote sensing for monitoring the grassland management.

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A questionnaire survey concerning evaluation of the multipul functions of grassland was conducted to female residents in Tochigi Prefecture. The results obtained were compared with those of paddy and corn fields and forest. Recreational, educational and refuge functions of grassland were evaluated greater than those of the other kinds of farmland. Absorptional, scenic, biodiversifying and psycological functions of grassland were evaluated as great as those of forest, and greater than those of paddy and corn fields.

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Fourteen varieties commercially available as forage rye (Secale cereale L.) were harvested at blooming stage for 2 years. Forage samples were chemically analyzed by both of detergent- and enzymatic-methods. Then, variability among varieties was investigated in feed compositions and growth characters, using statistical analyses such as analysis of variance and cluster analysis. Among 3 categories of variety classified according to earliness, morphology and breeding objectives, eleven varieties of extremely early maturing and two varieties of triticale were found to be homogeneous in each feed composition and possessed individual feed property respectively. Extremely early maturing group showed high contents of each fiber element and low digestibility, whereas the late variety contained high protein and low fiber and showed high digestibility. Triticale group showed intermediate composition of these two groups. From these results, it is concluded that farmers should put much emphasis on the difference of feed composition among varieties and not treat forage rye as a whole. From the results of regression analysis through all varieties tested in 2 years, it is suggested that the varieties with high CP (crude protein) contents in dry matter showed high digestibility of fiber and dry matter.

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Sixteen forage oats (Avena sativa L.) varieties were evaluated at milk-ripe stage for 2 years. Forage samples were chemically analyzed by both of detergent- and enzymatic-Methods. Then, variability among variety groups was investigated in feed compositions and growth characters, using statistical analyses such as variance and cluster analysis. Among 4 groups classified according to earliness, morphology and breeding object, extremely early maturing and medium maturing groups were found to be homogeneous in each feed composition and possessed individual feed property. Medium maturing thin-stem and late maturing groups showed comparatively large variation in feed composition. From these results, it is concluded that farmers should put much emphasis on the difference of feed composition among variety groups and not treat oats as a whole. By regression analysis of all varieties tested, it was suggested that the fiber digestibility was high in the CP (crude protein) content-rich and ADL (acid detergent lignin)-poor varieties. The dry matter digestibility was high in the CP-rich, ADL-poor and NDF (neutral detergent fiber)-poor varieties.

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