In the production of soiling crops, the most suitable planting density has to be determined according to the time for utilization and also to their cultivation method, because the growth habits and yields of these crops are affected by the planting density. In this report, some informations to get high production of sorghum species were obtained by applying various treatments of planting density on this crop, combining other tretments such as time of sowing, seeding methods, fertilizer, time of cutting, and height of cutting. 1. In high planting density of 15000 plants per are, the growth and the yield of sorghum sown in drill was better than those sown in space. 2. In the high-level fertilized plots, cutting at low height increased the yield, but close cutting at the beginning of internode elongation stage depressed the regrowth after cutting, resulted in the decrease of total yield. 3. Growth of the plant sown late (early July) in densed drill was quick and its yield was rather high, while its growing period was short. 4. Sowing in densed drill tended to increase the rate of leaf weight and the dry matter content.

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4 clones of distinctive characters which had been selected and propagated from a variety "Frode", were transplanted in the fall of 1964, to establish 6 kinds of sward which was different in plant density (HD : 400 plants/m^2, LD : 25 plants/m^2) and differentially fertilized with nitrogen (HN : 40g N/m^2, MN : 20g N/m^2, LN : 10g N/m^2). The initial harvests were cut at boot stage (May 17), heading stage (May 24), full bloom stage (June 6) and June 20, and, the second harvests were after each 6 weeks of the each intial cut. Characteristics of each clone judged from the growth of LD sward were : Clone 1-Tallesst plant height with a few tillers, Clone 2-Lower plant height with abundant tillers, Clone 3-Similar plant height and tillering to Clone 2, with leaves of lowest nitrogen concentration, Clone 4-Lowest plant height with weak tillering. 1. The initial yield was higher in the later cutting and the second yield was reverse, resulting in the higher total yield at the later initial harvest (Fig. 7) 2. When the initial harvest was, cut at earlier growth stages, Clone 2 or 3 with strong tillering capacity grew better and contributed much to the yield and density of the sward, whereas Clone 1 with tallest plant height progressively dominated the sward yield as the initial cutting was delayed (Fig. 8) 3. Tall erect clones may gradually dominate the sward when cut at hay or silage stage, instead, short clones with many tillers may maintain their persistency more easily when cut or grazed at earlier growth stages.

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A study was conducted in three different harvest-year swards to clarify the effect of cutting height and growth season on the regrowth of orchardgrass. The defoliation levels were 3, 6 and 12cm, and the process of regrowth was investigated weekly or fortnightly except winter-time. The seasonal changes of the vertical distribution of leaf, stem and total available carbohydrate were also investigated. With the higher level of defoliation, plant height, leaf area index, light interception and dry matter yield increased promptly, and the curve of yield marked the peak at an earlier stage, thereafter declining rapidly. Whereas, with the lower defoliation level, the regrowth was retarded and the curve of yield ascended gradually to the ceiling point, declining slowly thereafter. The difference of regrowth between the higher and the lower cutting heights was remarkable in summer. Dry weight and TAC concentration of stubbles reduced rapidly and their recoveries were retarded as the defoliation was severe. It was observed that dry weight and TAC content of leaf and stem at the base of the stubbles were especially scant in summer. The results suggest that the higher cutting height of orchardgrass must be associated with frequent defoliation and might be suitable especially when carbohydrate reserves are deficient.

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Regular survey of soil insects and some other arthropods were carried out in a mixture forage sward which was sown before five years. From March of 1966 to January 1967, once a month, four replicated soil samples (50sq.cm×20cm deep) were taken, and numbers of larvae or adults were counted, identified, and recorded at each collecting date. Recorded species were as follows. Insecta; 61 in Coleoptera, 6 in Hymenoptera, 3 in Orthoptera and in Diptera, 1 in Hemiptera, in Collembora and in Lepidoptera. Crustacea; 1 in Isopoda and in Polydesmoidea. Total number of these arthropods species was abundant in winter but decreased in summer. Among them, about 10 species belonging to Coleoptera and 1 species belonging to Curstacea were the harmful for forage plants. Most larvae of Coleoptera were found in the soil throughout the year, and did not show seasonal fluctuation. Exceptionally the larva of Colposcelis signata Motsch. was found only in summer, from July to August and a large larval population peak of Sitona hispidula Fab. was observed in May. As to vertical movement of soil insect, a population density of larvae was the highest in the first top soil (a depth of 0-5cm) during the season from March to October. The larvae slightly moved downwards from late autumn to winter but not so deep. From this observation it is able to say that the vertical movement of the larvae in a pasture field is less than that in other crops field such as tree nursary, and the field of wheat and upland rice plants.

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The present experiments were conducted to clarify firstly whether selection for yielding ability in a space planted condition which was commonly used in crop breeding, was usefull in a sward condition or not, and secondly what were the important traits as selection criteria. The three sets of half-sib families selected at random from the two random mating populations of Italian ryegrass were planted in space planted and sward condition. Data were recorded on forage yield, plant height, leaf width, tiller weight, tiller number and other agronomic traits. The first, second and third experiments were carried out in 1964-'65, 1965-'66 and 1966-'67, respectively. The results were summarized as follows : 1. The heritabilities of forage yield and tiller weight were higher in a sward than a space planted condition. 2. The correlation coefficients between two planting conditions of leaf width and plant height were high in all experiments, but that of forage yield was 0.624 in highest value. 3. In same planting conditions the trait that was most relative to forage yield was plant height, and the next was tiller number. 4. The tendency of correlation between forage yield in a sward and agronomic traits in a spaced planting differed according to the experiments. However, plant height positively correlated to forage yield in every experiments. 5. In a sward condition, the productivity of families was relatively higher when the upper leaf-blades were erect than when they were bent down. 6. Considering above mentioned results, in progeny test a selection for yielding ability is more efficient in sward condition than in a space planted condition, and plant height is the most important trait as a selection criterion in individual selection. In addition plant type and shape of leaves are considerable traits, too.

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Sixty varieties of alfalfa were classified to five groups according to their growth habits. Process of classification and growth habits of varieties belonged to each group were as follows : 1. There were observed varietal differences remarkably among 14 growth characters including the trends of spring and fall growth, plant vigor, and regrowth after cutting. Also, the regression was high between each growth character. 2. All varieties were divided by using these growth characters as the index of classification and finally their classification indices were calculated. Classification was done by this index. 3. Varieties which belonged to the 1st group were errect in plant shape and early grower in spring. They grew well even in the fall and good in regrowth after cutting. These growth habit indicated that this group did not readily response to the environment and could be adapted to warm region. The 3rd group was the intermediate. Varieties of the 5th group were prostrate type. Their growth was slow and growing period was shorter, indicating this group responded sensitively to the environments and was thought to be adapted to cool climate conditions. 4. From this classification of alfalfa varieties, it becomes easy to understand thic growth habit of each variety systematically and could select the best varieties adapted to warm region.

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Since 1964, a continuous grazing or whole year grazing system of the Japanese Black Breed of Cattle has been tried at the Ontake Stock-Farm of Otaki village in Nagano Prefecture. There, the woodlands in the 2nd Pasture of the Farm, have been used exclusively for winter grazing immediately after summer grazing in the grasslands of the 1st Pasture. The woodland pasture is situated at about 1, 600m above sea level on the south-facing slope of Mt. Ontake, being constructed mainly of such trees as birch (Betula platyphylla var. japonica), oak (Quercus rnongolica var. grosseserrata), larch (Larix leptolepis), and partly accompanied with sub-alpine trees such as hemlock (Tsuga diversifolia). The woodland floor is completely covered by a dwarf bamboo (Sasa senanensis) which offers indispensable fodders for grazing cattle throughout the winter season. On August 1968, some ecological surveys were conducted in the woodland pasture of this Farm to throw light on the influence of winter grazing on this dwarf bamboo. The plots surveyed were selected in the areas of heavy grazing and early spring grazing in addition to the ordinary winter grazing area. Under repeated winter grazing, plant height, density, branching, number and shape of leaves, leaf weight, and standing crop of the dwarf bamboo were affected in the following ways through the complicated process : Height : decreased lineally in parallel with the grazing intensity, besides much expanding variability in height. Density : decreased, but not so linear as the plant height. Branching : increased in number in parallel with the grazing intensity, and dead branches also increased. Number of leaves : increased dynamically as intensification of grazing. Shape of leaves : leaf area decreased, becoming slender in shape. Leaf weight : weight ratio of leaves to all organs above the ground decreased under ordinary grazing, though increased under heavy grazing. Standing crop : decreased in parallel with the grazing intensity. The data described above were compared with those of the summer grazing at the Takiue Station which had already been reported in the part 1 of this thesis. The information thus obtained supports the suggestions that the tendencies of which the dwarf bamboo affected by winter grazing represent are essentially the same as those by summer grazing. However, the degree of damages from which the dwarf bamboo suffers is considerably slight under winter grazing than under summer grazing.

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Growth analysis was applied on ladino clover swards for 44 days, from October to November at Tohoku University farm, located in temperate climate region. Two experimental swards were set up, the plot (1); the sward clipped the day just beginning the experiment, and the plot (2); the sward clipped at 22 days before beginning the experiment and had higher leaf area and higher plant height than the plot (1). The plot (1) was the control, and the plot (2) was the high LAI plot. On both plots wet and dry weight of leaf, root and stolon, and leaf area were surveyed in each week. Results were as follows : 1. The high LAI plot was suffered from frost and rain injury more severely than the control plot. Leaf area, net assimilation ratio and crop growth rate were decreased by frost and rain damage for about two weeks but recovered later. 2. Leaf area index was 3.5 in the high LAI plot but nil in the control plot at the beginning of the experiment. The both plot increased leaf area and attained 3.3 in the control plot and 5.7 in the high LAI plot after 3-6 weeks. 3. Net assimilation rate was naturally decreased with increasing leaf area index and was higher in the control plot than in the high LAI plot. But LAI-NAR relationship differed in both plots, suggesting the high LAI plot had higher capacity in light interception or higher capacity in photosynthesis per unit leaf area. 4. Crop growth rate was higher in the high LAI plot than in the control plot, since the former had higher LAI and relatively higher NAR as well. These results suggested that the long rest period in grazing or clipping was preferable for dry matter production than the short rest period in autumn.

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Although red clover plants have been generally called to be biennial, there are considerable differences in their persistence among varieties, and also, among individuals even within same variety. There had been, however, a question whether persistence of red clover plants was based on the essential persistence of the primary plants themselves, or on survival done vegetatively as in white clover. To slove this question, red clover plants of the first, second, third and fourth year in ages, respectively, were observed morphologically at the end of growing season; and also, morphological and ecological observations were carried out at intervals of one or two months from the seeding year to the third year. The results were summarized as follows : 1. Tap-root of the first year plant was observed to be vital, showing yellowish white color in both internal part and surface. In the second year plant, the tap-root began to show symptoms of deterioration, being brownish in internal part and surface, where less rootlets were attached. Tap-root was in progress of deterioration in the third year plant; and then, it was internally broken down and almost disappeared in the fourth year plant (see Fig. 3-13). 2. Node-rooting at stems of the primary plant was found in most of the first year plants (see Fig. 3-A), and some of the rootlets already went into the ground, attaching some root-nodules. And these rootlets generally prolonged 10-20cm in their length at the beginning of the second year season. Secondary plantlets appeared from the nodes, most of which showed rooting already, in the second year season and thereafter. Node-rooting and appearance of the secondary plantlets were most thriving in the third year plant (see Fig. 3-E〜Fig. 4-C, which correspond to the first-fourth year plants). New node-rooting was again found at sufficiently prolonged stem of the secondary plant in the fourth year season. 3. It was observed that there were two types in appearance of the secondary plantlets. That is, one was the outer side-type consisting of plantlets, which appeared from the lower position of nodes at stems of the primary plant and grew by themselves, being detached from the primary plant, after the stems had died (see Fig. 3-C). Another was the inner side-type, plantlets of which appeared around the crown of the primary plant. and were detached from the primary plant after the crown had been broken down Fig. (3-D). The former type of plantlets were generally earlier in appearance, and consequently, more advancing in growth than the latter type of those. 4. Mechanism, of the survival maintenance done vegetatively in red clover plants was very similar physiologically and ecologically to that in white clover plants (see Fig. 4-D). More precise study on this mechanism in red clover plants must give instructive suggestions to breeding, in which there would be possibility of early-stage selection of persistent plants, and also, to pasture management.

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