Red clover in Hokkaido, which was introduced from U.S. in the 1870's, has well adapted to climatic conditions in Hokkaido, and it grows now widely in fields and roadsides. Authors have investigated on disease-resistance (1960), durability (1959-1960), productivity (1955-1957), and fertilizing ability(1956) of local variety of red clover, which has been cultivated in Hokkaido for a long time. The summary of the results was as follows: 1). Disease-resistance: Resistance to red clover rust (Uromyces fallens KERN) was mainly investigated. The disease-injury was analyzed by "Degree of contraction of disease", and "Percentage of disease-contracted plants" which were calculated by the following formulas. Degree of contraction of disease =Σ(Ranking scale×Number of corresponding plants)/Number of total plants (Note). Ranking scales…0-5 Percentage of disease-contracted plants =Number of disease-contracted plants/Number of total plants×100(%) According to the results, resistance to rust-disease of the tested varieties was shown as follows: Very high…Merkur, Silo, and Leon High…Dollard, Kenland, and Kuhn Low…Local variety, Lakeland, Altaswede, Libel, Midland, Montgomery, and Rahn Very low…Medium red clover (imported, noncertified seed) 2). Durability: When plants of local variety were grown singly in 60cm×60cm, it was observed in the second year that 12.0-62.4% of plants were dead during passing the winter, and also, relatively many of the rest of the plants continued to be dead until the late autumn. The results also showed that there were relatively many non-durable plants whithin populations of local variety, and there were much differences in durability between strains originated from different areas. 3). Productivity: In the first year, some varieties from foreign countries showed higher productivity than local variety, but, in general, in and after the third year, they rapidly decreased their productivity, increasing dead plants. Therefore, local variety showed the highest total yield through all yieldingyears. 4). Fertilizing ability: For fertilizing ability, flower-heads of red clover plants collected from old timothy-red clover pastures were investigated. The results showed that fertilizing ability of local variety could be well estimated, on the fact that it was found even in bad climatic areas, such as Konsen and Tenpoku regions.

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The author microscopically observed the cross sections of leafblades of some 38 kinds of grasses cultivated and wild in Iwate Prefecture. These grasses had various types of bulliform cells, which were distinguished into 8 types as follows (see Table 1); Type I. Formed by upper epidermal and mesophyll cells, locating in each internerve. Type II. Formed by upper epidermal and mesophyll cells, locating in each internerve with a secondary small vein. Type III. Also formed by upper epidermal and mesophyll cells, being restricted to only the upper surface of the midrib. Type IV. Formed by upper epidermal cells, being restricted to the two portions both sides of the midrib. Type V. Formed by upper epidermal cells only, locating in each deeply grooved internerve. Type VI. Formed by upper epidermal cells, locating in each internerve which wach was not grooved so deeply as in Type V. Type VII. Formed by upper epidermal cells, locating in each flat or slightly grooved ioternerve. Type VIII. Formed by upper epidermal cells, locating in each primary internerve with a few secondary small veins. Under dry conditions, grasses having bulliform cells of Type I and II rolled their blades very rapidly, whereas those of Type VIII scarcely rolled. The blades of grasses which had bulliform cells of Type III and IV folded also rapidly. Grasses with the bulliform cells of Types V, VI and VIII rolled their blades an several degrees, and these movements were not related to the sizes and the features of the bulliform cells. In the present experiment, it was suggested that the entire structures of leaf blades and the physiological charactees of their bulliform cells with mesophyll cells near them, were more impertant to the rolling and folding mechanisms in these grasses.

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Some experiments were carried out to know an adequate cutting programme of Italian ryegrass sown with much fertilizer immediately after harvesting the rice plant of early and medium cultivation. 1. Frequent cutting, consequently young plants were cut, produced comparable amount of fresh and dry matter with the less frequent cutting until the internordal growth stage, but afterwards productivity decreased. Consequentry, the total yield decreased in the former. 2. Crude protein content in frequent cutting was higher throughout the stage than less frequent cutting, but the total crude protein yield was lower owing to the lower production of the total dry matter. 3. Little influence of the frequency of cutting on the tillering manual of grass was found except the following facts. When the grass was cut frequently, the internodal growth stage was delayed. Total number of stems in the stage was a little more owing to the delay of time when a proportion of stems with removed growth point increased. Consequently, main stem and the first tiller predominated in the forage until late season. On the contrary, after the internodal growth began, the proportion of the stems with removed growth point became higher so as to the second and third tillers predominated. 4. Therefore, it seems adequate to cut the grass frequently before the begining of the internodal growth but to do less frequently there after in order to get the high yield of forage of good quality.

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This experiment was conducted to study the relative contribution of the seeding ratio and the fertilizer treatment to the growth and the dry forage yield of timothy-red clover mixture. The following five kinds of seeding ratio, timothy vs. red clover (in number of germinable seed totally 8,000), were adopted in this study; 10:0, 7:3, 5:5, 3:7 and 0:10. Further six levels of fertilizer treatment were adopted; 2NPK, NPK, NP, NK, PK and none. Both factors were combined in all possible ways. Results obtained may be summarized as follows: 1. Each fertilizer treatment gave a respective effect on the plant height and the flowering date of both crops. As the ratio of timothy to red clover decreased, the plant height and the flowering date of timothy received a depressive effect (see table 3 and 4). 2. The ild diagrams of both crops under each level of fertilizer treatment showed that the density effect on the yield of both crops worked independently each other. however, the yield of timothy was found to be depressed by the density of red clover in the 2nd cutting (see Fig 1). 3. The interrelationship between the seeding ratio and the total yield of the 1st and 2nd cutting of each crop was discussed basing on the regression analysis.

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Special attention has recently been paid for utilizing orchard as a source of grass production as well as the fruit production. This experiment was carried out to make clear the difference of the productivity between the improved and the natural grassland where chestnut trees were grown. For this experiment two kinds of plot were prepared for two years since 1957. The chestnut seedlings were planted in the spring of 1957, and were grafted in April of 1960. Orchard grass and Ladino clover were sown on the improved grassland plot, and the same quantity of fertilizers were applied to the both grass land plots. The results are summaried as follows: 1. The herbage yield in the improved grassland plot was higher than that in the natural grassland plot. 2. As compared with the natural grassland, the improved grassland produced about three times more crude-protein and crude-fat, and also over two times more crude-ash. Applied fertilizers have been much more absorbed by grasses than by native grasses. The amount of N and K_2O absorbed by grasses surpassed the applied quantity. It was presumed that this result was gained by the comparatively high fertility of the soil. It is admitted, however, further studies are needed from the standpoint of the maintenance of the soil fertility, as the elements of applied fertilizers are absorbed both by the grasses and by the chestnut trees in the grass orchard. 3. In the grass orchard, the growth and fruit production of the chestnut trees were fovoured by the cultivation of grasses, on account of the improved physical and chemical condition of soil. 4. The fertilizers, especially nitrogen and potassium necessary for grass growing, were applied at several times a year, but no harmful effects on the chestnut trees were recognized. 5. The results of this experiment have led us to the conclusion that an improved grass orchard of chestnut tree will be beneficially operated not only as the source of grasses but also as the source of fruit production.

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The importance of sweet potato as a food crop has been recently decreased in Japan. Considering its high productivity and vigorous herbage growth in warm season when good fresh roughages tend to be short, the authors tried to make clear through 4 experiments how to grow the crop for producing high yields of both top or herbage and root as a forage crop. Experiment 1. The effect of fertilization upon the yield of top and root, and upon the protein content of herbage. Plots of four treatments, O (no fertilizer), PK, NP and NPK were set up in randomized blocks. Half of nitrogen (ammonium sulphate) was applied on Aug. 5 in the midst of growth. The crops planted on July 5 of 1952 were harvested 7 times from Aug. 10 up to Oct. 20. The top growth of NP and NPK exceeded that of O and PK after late August (Fig. 1 and 2). While, the root growth was delayed in the two plots with nitrogen, but in NPK it could reach the same level of the plots without nitrogen in September (Fig. 4). The contents of both total-N and pure protein-N were increased about 40% in average by the appli-cation of nitrogen (Fig. 5 and 6). From these results, much application of nitrogen is considered not only to raise the yields of top and root toge-ther with adequate amount of potassium but also to increase the protein content of herbage. Experiment 2. The influence of planting and harvesting times on the yield of top and root. Cut stolons were planted twice on May 23 and June 6, 1953. The crops were harvested 4 times from Aug. 19 to Oct. 12. The plots were arranged by split plot design. The top yield increased up to late September and after that rapidly decreased, showing no significant difference between the two planting times (Fig. 7). The root yield had increased up to the last harvest, indicating the superiority of early planting to late one except October (Fig. 8). The contents of both air dried matter and starch of root increased gradually up to Sept. 30, showing no significant difference between the planting times (Fig. 9, 10). Thus, the adequate time of planting may be early June, taking the the preceding crop into consideration. The harvesting time is considered adequate befor the leaves severely fall down however the root growth is not fully completed. Experiment 3. Adequate amount of nitrogen and potassium fertilizers. Three levels of ammonium sulphate, N_0, N_1 and N_2 (0, 2.6 and 5.3kg per a) were combined in split plots with the same levels of potassium sulphate. The crops planted on June 6 of 1953 were harvested 4 times from Aug. 7 to Nov. 12, when we had the earliest frost. The herbage yield showed clear increments with the increase of amount of the fertilizers. While, the root yield reached maximum at the middle level of N and K, and the effect of nitrogen was less than that of potassium (Tables 5 and 6). From these results, the level of K_1N_2, K_2N_1, K_1N_1 or so is considered practical from economical point of view, though the highest yield was obtained in K_2N_2. Experiment 4. Effect of top cutting in the midst of growth upon the yield. It was known from the above experimental results that herbage yield changed to decline in the latter half of growth probably due to fall of leaves under closed condition. So, cutting tops in the midst of growth was tried with and without both base and delayed fertilizers in order to find the contribution of the treatment to diminish the loss by leaf fall and to supply fresh herbage in earlier season than usual. The crops planted on May 25 of 1954 were cut of their tops at a height of about 30cm once on Aug. 10 or Sept. 10 before usual harvest (Oct. 20 in this case). Total top yield of twice cuts exceeded approximately 20-30% that of the check plot (no delayed fertilizer and no cut in the growth midst) except only the plot of no fertilixers. The cutting in August was superior in total herbage yield to that in September. The treatment raised L/S ratio, probab

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[in Japanese]

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