Each inflorescence of white clover bears many florets. They set seeds at highly varying rates. We examined the extent of this within-inflorescence variation for a field population and its consequence for seed size variation. A considerable variation in seed set at floret level was observed in the population. This variation was partially attributable to floret position effect, upper florets on intlorescence having significantly less seed set and smaller seed size than lower florets. Seed set was highly variable even among florets at near site on the same inflorescence. Nevertheless, white clover was likely to produce almost the same sized-seeds regardless of seed number per floret. This trend was stronger in lower florets than in upper florets. It is suggested that there is the possibility of selective investment of resource in the upper part of inflorescence.

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In order to clarify the characteristics of the tree-shade preferred by grazing cattle, microclimate inside shade, kinds of shade tree, and size of shade were compared between the shade used and not used by cattle in 9 hilly paddocks during the summer season. The shade preferences of cattle were not affected by the kinds of shade tree when the shade was produced mainly by broadleaf trees. Cattle preferred the shade wherein the wind velocity was the highest, and this trend became especially strong during the afternoon. The shade size also affected the cattle's shade preferences. The shades less than 4 a were more preferred by cattle than the shades more than 10 a. The proportion of the wind velocity inside the shades of more than 10 a to the outside decreased with the increase of shade size. However, this decrease of wind velocity with the increase of shade size was not evident in the shades less than 10a. From these results, it was concluded that the shade preference of cattle mainly depended on the wind velocity inside the shade.

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We recorded 103 species in 24 stands in the grasslands of Baiyinxile National Pasture, Inner Mongolia. Thirty of the species occurred at greater than 50 percent frequency in these stands, but their ranking in the communities varied according to the intensity of grazing pressure. Forty-three species were chosen as indicator species of grazing pressure. Species classed as Type I, which ranked most highly in communities under light grazing pressure, included Aneurolepidium chinense, Stipa grandis and Achnathelum sibiricum. Type II species, which were more important in severely grazed stands, included Carex korshinskyi, Cleistogenes squarrosa and Artemisia frigida. Kochia prostrata, Koeraria cristata and Potentilia bifurca maintained their abundance irrespective of grazing intensity. These species were grouped as type III. The three groups of species indicated intensity of grazing pressure on the grasslands. In order to evaluate the stand quality, a stand quality index (SQI) was devised based on the volume of indicator species in the stand. We gave scores of 4 to type I species, 0.25 to type II and 1 to type III species. The SQI was obtained as follows: SQI=Σ (rI.s), where rI is the relative importance value and s is the score of indicator plants. The SQIs of stands protected from grazing for the previous 16 years were 975 for Aneurolepidium chinense stands and 530 for Stipa grandis stands. The SQIs of the grazed stands varied from 47 to 748. In an experimental field previously investigated, grazing by eight or more sheep per ha caused stands to have SQI values of less than 100, which is indicative of over grazing. In growth form spectra of the stands, the prostrate (p) form increased and branched (b) form decreased with intensified grazing pressure. Species diversity of the stands showed a weak relationship with SQI.

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To obtain information about pasture-level, spatially heterogeneous grazing by large herbivores, pre- and post-grazing herbage masses and herbage consumption were non-destructively estimated in 182 59 cm X 50cm locations in a bahiagrass pasture grazed by cattle for six 2- day grazing periods from May to October. The animals tended to graze more locations in the pasture and consume more herbage from locations with larger herbage mass as the mean herbage mass of the pasture decreased. This tendency became evident when the mean herbage mass was below about 200gDMm^<-2>. In addition, the animals almost always showed a tendency of grazing locations with lower herbage masses with higher degrees of defoliation, reflecting patch grazing. This grazing manner was considered to be a maj or factor contributing to the maintenance of the spatial pattern of herbage mass and also a partial cause for the increased spatial heterogeneity in herbage mass with grazing. However, the patch-grazing pattern was not very stable, and this was considered to be a factor fluctuating the patch boundaries and consequently affecting the stability of the spatial pattern of herbage mass in the pasture.

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Seasonal changes in dry matter production and crude protein content in Nezasa-type grassland under cattle grazing were investigated. Aboveground phytomass increased rapidly after April and was about 300gDM/m^2 in July and August, and then decreased gradually. Leaves of Pleioblastus variegatus accounted for the third of aboveground phytomass. The maximum rate of change in aboveground phytomass was shown in May. Annual aboveground production was 324-378gDM/m^, and herbage consumption was 217-252gDM/m^2. Underground phytomass of P. variegatus increased by 319-649gDM/m^2 from spring to autumn. Crude protein contents of P. variegatus, Miscanthus sinensis and Arundinella hirta were high from April to May, and decreased gradually thereafter. Crude protein contents of leaf of P. variegatus were above 20% in April. Leaves showed higher crude protein contents than stems. Crude protein contents of rhizome and stem of P. variegatus tended to increase from summer to autumn.

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As part of a study on the heading characteristics of sorghum spp., the effects of temperature changes on the final leaf number and the leaf emergence rate on the mainstem were examined by changing the sowing date and planting year, using 57 commercial cultivars. The responses in the number of leaves to temperature varied substantially among different cultivars. On the basis of the degree of the response, cultivars could be clearly classified into two groups;in one group, the number of leaves obviously increased with a temperature increase, and in the other group, the temperature changes did not have a significant effect on the number of leaves. Moreover, each of the two groups could be further classified into four and three sub-groups based on the degree or pattern of the responses, respectively. Although the leaf emergence rates based on calender days increased with an increase in growth temperature, those based on an effective heat unit summation above 12℃ were approximately constant, regardless of thetemperature changes. The heat unit summations required for the emergence of one leaf was 36.5℃ in sorghum and sorghum × sudangrass, and 40℃ in sudangrass.

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This fundamental experiment was designed for a better use of abandoned paddy fields to prevent their devastation by cultivating waterhyacinth and using its harvested materials as feedstuff, and to study the influence of the sources of nitrogen on the growth and nitrogen uptake of waterhya cinth in the model paddy field of closed water system. The sources of nitrogen were ammonium (NH_4-N), nitrate (NO_3-N), amide (NH_2-N) and the animal waste (pigpen waste). These equivalent weight for 40ppm levels of nitrogen fertilizers were added to the water for basal dressing and every 10 days, and the plants were harvested sixty days after the transplanting. Plants grew well in both the NH_-N and the animal waste groups when estimated from numbers, dry matter (DM) weights of the plants. The amount of nitrogen uptake were higher in both the NH_-N and the animal waste groups than the NH_-N and the NO_-N groups. Changes in pH of culture waters indicated that the NH_4-N decreased (acidic) and the NO_3-N increased (slightly basic) during the cultivation, and both the NH_2-N and the animal waste groups changed gradually. EC of the NH_-N and the NO_-N increased in accordance with manuring, however the NH_2-N and the animal waste groups increased little.

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Determination was made of the recovery of slurry nitrogen (N), mineral content, fermented quality and nutritional yield of rice based on rate and timing of fermented dairy cow waste application. Rice with V-type leaves was cultivated at higher dosage of N (1.5 or 3 times the normal) using slurry as basal or split at 80 kg N ha^<-1>. The recovery of N ranged from 8.8% to 30.9%, and was higher by split application. The K/(Mg+Ca) equivalent ratio was less than 2.2 subsequent to the milk-ripe growth stage. Fermented quality of rice plant improved with maturity and nutritional value was greater cultivated plots subject to split application. The recovery of N and nutritional yield was thus superior with split application.

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The seasonal changes in primary production were investigated over 3 years on tall fescue pasture grazed by Japanese Black breeding cattle. Dry matter weight changed in the range of 443.6-1,065.2g DM/m^2 for aboveground part, 40.1-209.5gDM/m^2 for surface litter, and 107.0 g-923.0 g DM/m^2 for underground part. All through the year dry matter weight of aboveground parts on tall fescue pasture was higher than that of other temperate grass pastures reported in other papers. This tendency was remarkable after summer. Total dry matter herbage intake by grazing cattle was 1,104.6g DM/m^2/year in the average value over 3 years. Net production increased in spring and autumn, and that in autumn was higher than that in spring. Total net production was 2,195.0g DM/m^2/year in average value over 2 years. On the basis of the results obtained, characteristics of primary production on grazed tallfescue pasture were discussed.

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A total of 110 items of forage sorghum were harvested at the dough stage, and the digestibility of their foliage was evaluated. The digestibility experiment was conducted using the nylon-bag method on three Japanese black cows fitted with rumen fistula. The digestible dry matter content showed variation between 60.8-87.4%. The lower values corresponded to the content in inferior grass hay (56.0-61.2%) or rice straw (56.8%) tested under the same conditions, while the higher values exceeded the content in corn silage (79.9%). In particular, brown midrib lines and varieties with high culm juice brix were highly digestible. The water-soluble matter content varied between 21.5-60.0% showing a significant positive correlation with the digestible dry matter content (r= +0.55). The digestible structural matter content varied between 19.2-57.0% and showed a significant negative correlation with the watersoluble matter content (r=-0.76). The digestibility characteristics of brown midrib lines were distinctly different from those in the normal varieties. It was attributable to the high digestible structural matter content in comparison to normal varieties (10-15%), rather than the high water-soluble matter content.

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A water culture system and ^<15>N-labelled nitrogen was used to investigate why the growth of alfalfa treated with ammonium nitrogen exceeded the growth of alfalfa treated with nitrate nitrogen. Plants treated with ammonium nitrogen showed higher levels of dry weight, total nitrogen content, soluble nitrogen content, insoluble nitrogen content and ^<15>N-labelled insoluble nitrogen content than plants treated with nitrate nitrogen. Just after ^<15>N-labelled nitrogen treatment, the ratio of ^<15>N-labelled soluble nitrogen content to ^<15>N-labelled total nitrogen content in plants under conditions of nitrate nitrogen was higher than that in plants under conditions of ammonium nitrogen. The experimental results show that the growth of plants treated with ammonium nitrogen surpassed the growth of plants treated with nitrate nitrogen. This is because alfalfa absorbed more quickly the ammonium nitrogen than the nitrate nitrogen. Thus, it was shown that the protein synthesis ability of alfalfa is superior under conditions of ammonium nitrogen.

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Field experiments were conducted at Exp. Farm of Tohoku univ., Naruko, Japan in 1995-1997 to examine the effects of porous hydrate calcium silicate (PS) on the silica nutrition of turf grass. Silica contents of perennial ryegrass (Lolium perenne L.), bentgrass (Agrostis palustris Huds.), tall fescue (Festuca arundenacea Schreb.), kentucky blue grass (Poa pratensis L.) treated with PS 300g/m^2 increased by 29%, 35%, 23% and 27% compared to that of each control. In addition, silica contents of new turf grass cultivar 'Miyako', natural crossing cultivar of Japanese lawngrass (Zoysia japonica Steud.) and Korean lawngrass (Zoysia tenuifolia Willd.) increased with increasing application rate of PS over the study period. The silica contents of final cutting stage treated with PS 100 g/m^2 and 300 g/m^2 increased by 9% and 15% in 1996, and 11%0 and 18% in 1997, respectively, compared with that of the control. Total clipping yields of Miyako were unaffected by PS application in both 1996 and 1997. Leaf colors of Miyako in 1996 slightly increased with the increasing the application rate of PS but not in 1997. Nitrogen contents of Miyako tended to decrease with increase in application rate of PS in 1996, but not in 1997. In conclusion, PS is an efficient ameriolant for improving the silica nutrition of turf grass without any detrimental influence in beauty of turf.

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Field trials were conducted at Exp. Farm of Tohoku univ., Naruko, Japan in 1997 to examine the effects of porous hydrate calcium silicate (PS) on the wear resistance, insect resistance and disease tolerance of turf grass using a new turf grass cultivar "Miyako". Silica content of Miyako leaves treated with PS 100 and 300g/m^2 increased by 18 and 26%, respectively, compared to that of the control. With the application of 300 g/m^2 PS, tractions of turf leaves at 4 cm and 6 cm height, indicators of wear resistance, significantly (P<0.05) increased by 7.0% and by 9.0%, respectively, compared to that of the control. With PS 300 g/m^2 treatment, feeding amount of turf leaves by Rusidriaa depravata BUTLER larvae significantly decreased by 41% (P<0.05) compared to that of the control. Degrees of disease severity affected with the brown large patch (Rhizoctonia solani) tended to be reduced by PS application. In conclusion, porous hydrate calcium silicate is an effective material for improving the wear resistance, insect resistance and disease tolerance of turf grass "Miyako".

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