In order to clarify the relationships among 23 cultivars or strains of 5 species, L. perenne, L. multiflorum, L. rigidum, L. remotum, and L. temulentum, in the genus Lolium, leaf materials sampled from 483 plants were assayed by the horizontal starch gel electrophoresis for an enzyme system, phospho-gluco isomerase (Pgi-2). The results obtained were as follows: 1. Seven bands were detected on the zymograms of Pgi-2, and the existence of 10 zymograms in all was confirmed. 2. Pgi-2 isozyme pattern was independent of the leaf age. 3. For the inbred species, L. remotum and L. temulentum, all plants of each species examined were identical with a common simple banding pattern. For the outbred species, L. perenne, L. multiflorum, and L. rigidum, several different zymograms were observed in each cultivar or strain. 4. Since all of the outbred species could not be identified with a common simple banding pattern, Nei's genetic distance for testing the distinctiveness and the relationships of cultivars, strains and species in the genus Lolium, was applied. As the results, it was suggested that L. rigidum was most similar to L. multiflorum, L. perenne was comparatively similar to L. rigidum, L. multiflorum, L. remotum and L. temulentum, and both L. rigidum and L. multiflorum were most different from both L. remotum and L. temulentum. Besides, it was assumed that L. remotum was exceedingly similar to L. temulentum. 5. Assumption on the phylogenetic relationships among Lolium species obtained from the above mentioned results coincided nearly with the Terrell's hypothesis (1968). Further-more, the grouping of L. multiflorum cultivars (2n=14) on the basis of Pgi-2 isozyme coincided well with the grouping of those cultivars on the basis of peroxidase isozyme variation in the author's previous paper (1982).

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Rooting behaviors of creeping stems were microscopically examined with commercial cultivars of five turf grasses i.e., Poa pratensis, Agrostis alba, Phalaris arundinacea, Paspalum notatum and Cynodon dactylon. Sections were prepared either in paraffin- or celloidine embedded cakes. Results obtained are as follows: 1. The earlest tillers emerged at the proximal node of a main stem grow horizontally or diagonally upwards in seedling with a few root primordia of roots at a short distance from the tiller apexes. 2. In adult creeping stems, roots emerge at the distal recognizable node, indicating that the root primordia are formed at the bases of the newly elongating internodes that are located at a few milli-meters from the shoot apex. 3. The number of roots at the rooting node varies according to species examined i.e., two to three both in above-ground stems and rhizomes in P. pratensis, three to six in stolons and rhizomes of A. alba, none in erect stems and two to four in rhizomes of P. arundinacea, six to seven in stolons of C. dactylon and single root in stolons of P. notatum. 4. Transversal disposition of roots at the rooting nodes is characteristic according to species examined ; three roots emerge at an angle of 120° in P. pratensis and four roots at right angle in P. arundinacea, three to six roots in rather irregular arrangement in A. alba and a root downward in P. notatum.

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The purpose of this investigation was to clarify the effect of some environmental factors on denitrification from the soil. Denitrification was estimated by measuring nitrous oxide evolved in the presence of acetylene. Acetylene blocked the pathway from nitrous oxide to molecular nitrogen. Results are as follows. 1. The optimum acetylene concentration to block the pathway from N_2O to N_2 was 5% (V/V) in this experiment, and the concentration did not affect the microbial activity. 2. Soil water critically influenced the amount of denitrification. Denitrification did not take place at 50% of maximum water holding capacity or less, while 62% of soil nitrate was denitrified at 95% of maximum water holding capacity or more. 3. When various forms of nitrogen were applied to the system, denitrification from urea or ammonium sulfate was almost negligible whereas that from nitrate or nitrite was severe. 4. Denitrification increased with the increment of nitrate addition, but denitrification rates remained almost constant regardless of soil nitrate content. 5. The addition of forage powder or glucose accelerated denitrification loss from nitrate in soil, which suggested forage powder added was served as energy source for denitrifiers. 6. Denitrification increased with the increase of soil pH.

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Ladino clover and orchard grass were grown in 1/2000 a pots at the sowing ratios of 10:0, 8:2, 5:5, 2:8 and 0:10 (ladino clover: orchard grass) in order to investigate the variation of growth and symbiotic N fixation capacity of ladino clover in mixed swards. In addition, ladino clovers were grown in 1/10, 000 a pots at the different shading levels (100%, 71%, 45% and 23% of full sun light) to elucidate the effect of mutual shading in mixture swards in a separate experiment. The effect of NO_3-N concentration on the symbiotic N fixation capacity of ladino clover was also investigated in a water culture. Results obtained are as follows. 1. The growth of ladino clover was markedly decreased in both top and root by association with orchard grass, and it was more critical at high N treatment than at the low N treatment whereas the top growth of orchard grass did not reveal the large differences among the different sowing ratios in any N treatment. The root growth of orchard grass, however, showed a gradual increase with the increment of sowing ratins. 2. The legume ratios calculated from the yield of both forages were higher at the low N treatment than at the high N treatment. At both low and high N treatments, the legume ratios were reduced rapidly with the decrease of sowing rations of ladino clover from 10:0 to 8:2, but no significant differences were present among the sowing ratio treatments of 8:2, 5:5 and 2:8. The simmilar tendency was observed on root. 3. Symbiotic N fixation capacity/pot was reduced drastically with the decrease of sowing rations of ladino clover at high N treatment whereas they revealed the almost same values as that of ladino clover pure culture at low N treatment until the sowing ratios of ladino clover decrease to about 50%. 4. A shading imposed on ladino clover (about 70% of full sunlight) resulted in a remarkable decrease of yield and symbiotic N fixation capacity/pot. Nodule formation/plant was not affected by shading to the 45% of full sunlight. 5. In a water culture of ladino clover, symbiotic N fixation capacity was reduced with the increase of N0_3-N concentration in the culture solution, and the N fixation capacity was recovered by the removal of N0_3-N from the media. 6. The symbiotic N fixation capacity of ladino clover grown in 10 ppm N0_3-N culture solution was higher in the without renewal plot of culture solution than that in the renewal plot with weekly intervals and the different values between the two plots were supposed to be resulted from the different concentrations of N0_3-N in the media of both plots.

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To study the seed reproduction of a population of timothy (Phleum pratense L.)-a perennial and wind-pollinated grass, the intra-population variations of the seed-set rate under grazed and ungrazed conditions were examined in marsh, slope and flat areas of a pasture located in Shizunai, Hokkaido. In addition to this field observation, both the selfing rate and the potential seed-set rate were measured. The potential seed-set rate was measured under the high density of panicle condition. The results were as follows: 1. The selfing rates examined by bagging were low (1-3% in average) and the potential seed-set rates were almost 100%. 2. The seed-set rates of the pasture population ranged from 1 to 23%, being differed among the adjacent subpopulations, and decreased in the descending order of areas of marsh, slope, and flat. Within each subpopulation, there were considerable variations in the seed-set rates up to 10-40% in maximum. 3. These results suggest that the quantity of pollen reaching its target was few in the flat, because reproductive tillers were lodged and shortened by grazing pressure. On the other hand, many pollen reached its target in the subpopulation in the marsh, because reproductive tillers were not lodged and their distributional pattern was aggregate. 4. The seed-set rates of timothy under the ungrazed condition were 36% in the flat and 47% in the marsh. 5. The seed-set rates of timothy population were different among the adjacent subpopulations diversified by grazing pressure, vegetation and distributional pattern of timothy plants. The population consisted of the various subpopulations closely related to their own local neighbouring environment.

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The distributional patterns of timothy and the spatial relationships between timothy and orchardgrass were observed in the experimental fields of the 17-year-old pasture in Shizunai, Hokkaido. Ten quadrats were set in marsh (Marsh-A, B, C, D), lightly grazed flat (Flat-1, Flat-3A, 3B, 3C, 3D) and heavily grazed flat (Flat-2). All timothy ramets, and orchardgrass whose basal diameter was over 5cm were mapped. Their basal diameters were measured from the map. The results were as follows: 1. The basal diameters of timothy were ranging from 0.5 to 30cm. The frequency distributional pattern was L-shaped in each quadrat. In Flat-2, many small ramets were observed, and almost 70% of them were under 1cm in diameter. 2. The distributional patterns of timothy were analysed by Morishita's I_δ index. In marsh, the distributions were more aggregate than the others, and those in Flat-1, Flat-2 and Flat-3 were less aggregate. When the size of timothy was classfied into three groups ; large group: basal diameter>5cm, intermediate group: 1-5cm, small group: 1cm≧, small group was aggregate and large group was random in the distribution. 3. In Flat-1 and Flat-3 with lightly grazing pressure, orchardgrass was dominant and formed tussock. Timothy was suppressed by this species. The distributional patterns of orchardgrass were random or uniform, and they were different among the size classes (large group: basal diameter>15cm, intermediate group: 10-15cm, small group: 5-10cm) ; that of small group was lightly aggregate, but large group was uniform in the distribution. 4. The relationships of the distributional patterns between timothy and orchardgrass, among the size classes of timothy, and among the size classes of orchardgrass were analysed by Morishita's R_δ index. R_δ-values were lightly negative between timothy and orchardgrass, positive among the size classes of timothy, but negative among the size classes of orchardgrass. 5. These results show that the distributional pattern of timothy was regulated by that of orchardgrass, and timothy dispersed imperfectly in the open space among the stands of orchardgrass.

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This research was conducted for a 2-year period to investigate the effects of cutting in spring on the seed production, fertility and natural reseeding of some temperate grasses. The cutting treatments were: a) uncutting from early spring until early August (S_0) and b) uncutting until early August after cutting in late April or early May (S_1). Grasses used were orchardgrass (cv. Potomac, Akimidori, S143), tall fescue (cv. Kentucky 31), Kentucky bluegrass (cv. Baron), perennial ryegrass, smooth bromegrass (cv. Carlton) and red top. The results obtained were summarized as follows: 1. The first heading time, flowering time and full ripe stage in S_1 treatment were obviously later than in So treatment. The degree of the delay in S_1 treatment was greater in Potomac orcardgrass, Akimidori orchardgrass, tall fescue and perennial ryegrass which showed early maturing. 2. In all species, number of seed heads, seed yield, 1000 seed weight and quantities of fallen seeds in August were depressed by cutting in spring. The percentages of ripening seeds in full-ripe stage and in early August were significantly higher in So treatment than in S_1 treatment. 3. Emergence of seedlings in orchardgrass, tall fescue and perennial ryegrass mainly in So treatment began from about late June or early July, but all of those seedlings died after cutting in early August because of a high temperature and a drought. After that, the seedlings of those species emerged again from late August or early September. So treatment was markedly superior to S_1 treatment in seedling emergence and establishment. Perennial ryegrass and orchardgrass in S_0 treatment were obviously superior to other species in emergence and establishment during 2-year experimental period.

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Weekly changes in number of shed seeds and germination percentage in orchardgrass (cv. Potomac) and tall fescue (cv. Kentucky 31) were studied to evaluate the suitability of these species to natural reseeding and to determinate the time when the mature grasses should be utilized in order to obtain the good germination and establishment of shed seeds. These experiments were conducted at Chugoku National Experimental Station located in the western part of Japan. The results obtained were summarzied as follows: 1. Tall fescue was earlier both in the date of full-ripe stage (June 14) and the date of shedding initiation of seeds (June 5) than orchardgrass (June 19 and June 13 respectively). The number of seeds produced per m^2 in orchardgrass was 129×10^3, being about twice as many as that in tall fescue (63×10^3 seeds). There was no difference in fertility between these two grasses. 2. Great and small similar peaks were observed in the trends of seeds shedding in two grasses. The great peak occured during late June-early July in orchardgrass and late June in tall fescue, while the small peaks did during early August in both species. These two peaks showed remarkably smaller in tall fescue than in orchardgrass. More than eighty percent of the whole ripenning seeds produced both in two species have shed until middle July, the end of rainy season, in western Japan. 3. The germination percentage of the seeds shed from late June to middle July, at the rainy season, was 18-29% in orchardgrass and 81-90% in tall fescue. But the percentage in early September when was suitable for seed emergence and seedling establishment was approximately more than 90% both in two species. 4. From these results, it was concluded that the time of utilization of mature grasses for natural reseeding might be after middle July in orchardgrass and early July in tall fescue due to the change in the numbers of shed seeds, and that orchardgrass might be more suitable for natural reseeding than tall fescue because of a large number of shed seeds and low germination percentage before the end of rainy season.

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The characteristics of growth and dry matter yield of forage crops and soybean were studied for 4 years in conversion from paddy field of ill-drained cleyey soil into upland field. Species used were corn (Zea mays L. cv. Takanewase), sorghum (Sorghum bicolor Moench cv. Pioneer-988), rhodesgrass (Chloris gayana Kunth cv. Katambora), green panic (Panicum maximum Jacq. var. tricoglume Eyles) and soybean (Glycine max Merr. cv. Enrei). The methods of cultivation were same for 4 years according to standard methods in this district. The seeding time of 5 species were the middle of May, and the harvesting time was yellow-ripe stage in corn, heading stage in sorghum with 2 times of cutting, and vegetative-heading stage in rhodesgrass and green panic with 3 times of cutting. Soybean was harvested at maturing stage. The results are summarized as follows ; 1. Growth and dry matter yield of all crops were poorest in the first year after conversion, but it increased with the lapse of time, and became highest in the 4th year. The ratio of dry matter yield of first year to 4th year was 90% in sorghum, 80% in rhodesgrass and green panic, 76% in soybean and 65% in corn. In the first year the yield of corn was poorest of all the species and in the third year it was also low suffering from wet injuly in vegetative stage. On the other hand, sorghum had little changes in yield with years, and soybean was as unstable as corn. The authers considered that sorghum is more stable than corn in converted upland field with ill-drained clayey soil. 2. Low dry matter yield of corn in the first and third years after convertion were accompanied with low yield of ear, and it seems that the inhibition of N uptake was the major cause. The yields of all crops were increased with increase of N fertilization, especialy corn had much effects on the ear yield.

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The study was carried out to examine the effects of preseeded temperate grasses on the bahiagrass growth and forage production during estiblishment of bahiagrass pasture. Study sites were north and south aspects which were both about 25°-30° slopes at about 400m of altitude in Miyazaki prefecture. Comparisons were made between two treatments ; A mixture of perennial ryegrass (Lolium perenne L.), tall fescue (Festuca arundinacea Schreb), Kentucky bluegrass (Poa pratensis L.), redtop (Agrostis alba L.) and white clover (Trifolium repens L.) was preseeded on Sept. 11 in 1979 and bahiagrass was overseeded on May 21, 1980 (Temp+Bahia plot), and bahiagrass was seeded alone on May 21, 1980 without preseeding temperate grasses (Bahia alone plot). The results obtained were as follows ; On north aspect, winter survival of bahiagrass was very poor and almost no bahiagrass production was recorded after first year on both Temp+Bahia and Bahia alone plots. On the contrary, on south aspect, bahiagrass became dominate gradually in course of time of years on both plots. Temp+Bahia plot showed better bahiagrass growth at second and third years than on Bahia alone plot. Lesser weeds invasion on Temp+Bahia plot in spring appeared to moderate the suppression of bahiagrass growth by weed species during spring to early summer. Temp+Bahia plot also showed longer productive season, significantly greater annual forage yields.

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An investigation was made to clarify the effect of aspects on seedling establishment and forage production of temperate grasses at lowland hillside in southern part of Kyushu. The study sites were on north and south aspects of slopes which were both about 25°-30° angles, at about 400m of altitude in Miyazaki prefecture. A mixture of seeds composed of perennial ryegrass (Lolium perenne L.), tall fescue (Festuca arundinacea Schreb), kentucky bluegrass (Poa pretensis L.), redtop (Agrostis alba L.) and white clover (Trifolium repens L.) was seeded on September 11, 1979. Seedling establishment was observed and herbage was harvested about once a month during growing seasons in 1980 and 1981. Daily soil temperature at 5cm depth and soil moisture at 2-7cm depth were measured several times a year from Sept. in 1979 to Oct. in 1981. Results were as follows: 1. Seedling numbers of grass species and white clover measured at five weeks after seeding were far less on south than on north aspect, and seedling growth was depressed on south aspect. 2. Total forage yield was significantly lower on south aspect in both 1980 and 1981. Total forage yield of grasses on south aspect was about half that on north aspect. 3. South aspect showed more rapid deterioration of grass species, especially perennial ryegrass, and showed more rapid invation by weed species. 4. On south aspect, conbination of high soil temperature and low soil moisture during summer to early autumn appeared to limit germination and seedling growth, and to cause deteriolation of temperate grass species.

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In this experiment, dry matter yields were compared for a 5-year period in a double cropping field and a perennial cutting meadow including variations in chemical fertilizer, daily cattle slurry, farmyard manure and soil amendment matters (fused phosphate and super phosphate) applications. On the double cropping system, barley was cultivated as a winter crop followed by corn grown during summer and these two crops were harvested at late dough-ripe stage. On the cutting meadow, orchardgrass was harvested 4 or 5 times a year. The results obtained are summarized as follows ; 1. In the double cropping field, plots receiving cow excreta, especially the heavy application plot of daily cattle slurry (A4) showed high dry matter yields for the 5-year period. Average dry matter yield per year was 2179kg/10a in A4. 2. In the orchardgrass cutting meadow receiving daily cattle slurry, dry matter yields were higher in fused phosphate application than in super phosphate application. 3. In the case of daily cattle slurry, there were a little changes of dry matter yield in barley for the 5-year period. Farmyard manure gradually increased the dry matter yield of barley as the year proceeds. But dry matter yield in barley declined at chemical fertilizer. Dry matter yield of corn declined at all fertilizer application levels. However, high application of farmyard manure showed a little changes in the yield of corn for the 5-year period. A similar tendency was observed in orchardgrass. 4. In the double cropping field receiving chemical fertilizer, dry matter yield were higher in fused phosphate application than in super phosphate application. However, a similar effect was not observed in orchardgrass.

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It was examined for four years that the effects of amount of chemical fertilizer, dairy cattle slurry and farmyard manure and application of soil amendment matters (fused phosphate and super phosphate) on chemical properties in soils of double cropping and cutting meadow fields, and that mineral contents and their balance of corn, barley and orchardgrass. 1. The application of cow excreta (dairy cattle slurry and farmyard manure) rised the nitrogen fertility of double cropping field and cutting meadow field soils. This effect by application of farmyard manure was larger than that of dairy cattle slurry. But it seemed that effect of enlarging the nitrogen fertility of both soils was larger in amount of cow excreta than the kind of one. 2. Ca and Mg contents of both soils were higher in order of farmyard manure, dairy cattle slurry, chemical fertilizer. Especially Mg contents of both soils were remarkably high in the treatment of fused phosphate. Therefor Ca/Mg ratio of both soils in the treatment of fused phosphate were lower than that of super phosphate, and were lower than those of diagnosing standard (4-8). K contents of both soils in the treatments of cow excreta were higher than those of chemical fertilizer, especially highest in the treatment of dairy cattle slurry, and higher in fused phosphate than in super phosphate. Therefor Mg/K ratio was lowest in the treatment of dairy cattle slurry-super phosphate, and lower than those of diagnosing standard (more than 2). 3. N, P and K contents in clipped part of corn, barley and orchardgrass in the treatment of cow excreta were higher than in chemical fertilizer, and higher in the treatment of high application level. The effects of applided fused phosphate and super phosphate were different in crops. That is, N, P and K contents of corn were higher in the treatment of fused phosphate than super phosphate, but not recognized same trend in barley and orchardgrass. 4. Ca and Mg contents of crops were higher in the treatment of chemical fertilizer than that of cow excreta, and difference of value was large in Ca not Mg. In the treatment of fused phosphate Mg content was high but Ca content was low. Reversely in the treatment of super phosphate Mg content was low but Ca content was high. 5. K/(Ca+Mg) ratio of crops in the treatment of cow excreta were higher than that in chemical fertilizer, and higher in high application level of cow excreta. K/(Ca+Mg) ratio in clipped part of corn and barley on high application level of cow excreta were more than 2.2, and mineral balance of those crops seemed ill-balanced. K/(Ca+Mg) ratio of orchardgrass were more than 2.2 in all treatment. 6. Ca/P ratio of crops were higher in the treatment of chemical fertilizer than in cow excreta, and were high tendancy in the treatment of super phosphate than fused phosphate. Ca/P ratio in clipped part of corn, barley and orchardgrass were less than 1, and mineral balance seemed ill-balanced.

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Pure pastures of 52a of tall fecue, 20a of dallisgrass and 46a of bahiagrass were established in Kyushu Agricultural Experiment Station, Nishigoshi Kumamoto and seasonal procuctivity of each grasses were investigated measuring each months growth. As a result, tall fescue showed even productivity from March to October except severe decrease of growth in August, while dallisgrass and bahiagrass showed the growth pattern with one peak in June and in July respectively. And dallisgrass showed less growth except in June while bahiagrass showed comparably higher growth in June, August and September. Six Japanese brown cattle with average body weight of 650kg were grazed in rotation among these pastures resulting shortage of grasses in spring and autumn and excess in summer. Therefor it is suggested suitable acreage ratio of 7:3 of tall fescue to tropical grasses instead of 4.5:5.5 in this experiment. Longer interval of grazing resulted the decrease of productivity (total annual yields at the commencement of each grazing) of dallisgrass and bahiagrass, decrease of intake ratio of tall fescue and bahiagrass, and decrease of stubble numbers of tall fescue and dallisgrass. From this result, longer interval of grazing is considered to be not suitable for the management of these pastures. Comparison of palatability of each grass in terms of intake ratio was made, resulting higher intake ratio of dallisgrass followed by tall fescue and bahiagrass. All three grasses decreased their intake ratio during summer.

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Ten tropical grasses which survived under winter condition in Nishigoshi, Kumamoto were grazed and palatability, volume of intake and density of pastures were investigated. Another experiment for estimation of seasonal productivity was also conducted cutting the same ten grasses at another experimental field. Intake ratio was calculated with the grass weight at the start and at the finish of grazing. In terms of intake ratio and scoring for palatability, sorghum cv "Silk" and carpetgrass showed highest palatability followed by St. Augustinegrass, vaseygrass, switchgrass, little bluestem and knotgrass, while bermudagrass cv "Common", bermudagrass cv "Tifton 44" and weeping lovegrass showed poorest palatability. As the important grasses for grazing in Kyushu, dallisgrass and bahiagrass were scored for palatability in the same grazing field, where dallisgrass showed highest palatability while bahiagrass showed poor palatability. Lower palatability was correlated to higher dry matter percentage of grasses, suggesting lower palatability of heading shoot and poorly growing leaves which have higher dry matter percentage. Plant densities were kept in good condition in both creeping type and erect type grasses under grazing condition except weeping lovegrass which decreased stubble numbers. From the cutting experiment, bermudagrass cv "Common" and bermudagrass cv "Tifton 44" showed even seasonal productivity, and knotgrass, carpetgrass and vaseygrass showed increasing productivity with the advance of season, while St. Augustinegrass, weeping love-grass, switchgrass and little bluestem showed decreasing productivity with the advance of season. On the other hand, seasonal fluctuation of intakes/ha were not same as seasonal cutting yields because of different palatability of each grasses. As a result of total investigation, carpetgrass, sorghum cv "Silk" and vaseygrass were considered to be promising grasses for grazing in Kyushu.

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The deterioration of steel materials was made clear by investigating pasture fences which were constructed in the snowy highland of Iwate Prefecture in 1976-1979. These fences were composed V-shaped steel posts with over 450g/m^2 zinc coating and 4-barbed wire made of # 14 wire with over 22g/m^2 zinc coating. The rust on the surface of post was not found except on a part of the post's head which was hit at the time of fence construction, and a part of which the small hooks of post were broken by the snow settling load. The rust of the barbed wire was found much more on which the wire was older and on the upper step of the wire (Fig.1). The breaking of the barbed wire was found more in the second and third wire from the top than in the top or the bottom on 4-wire fence (Fig.2). Above 70% of these breaking occured within 20cm of the post (Fig.3). It is surmised that the breaking of the wire occured mainly by the snow settling load than a lowering of wire strength with the rust because of a low correlation between the rate of the wire's rust and the percentage of the wire's breaking. From the maintenance stanpoint for pasture fences in the snowy area, the useful life of the barbed wire needs more zinc coating. As the management of fences to decrease the breaking of the wire, it is necessary to develop the fence construction method which the wire is not loosened, and to plan how to hang the wire on the post and how to fix up the loosened wire.

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Italian ryegrass containing large amounts of nitrate was used for the six experiments as silage material. The material grasses of experiments 1, 2 and 3 were not wilted and ensiled immediately after harvesting. The material grasses of experiments 4, 5 and 6 were wilted in the field for 3 or 4 days. In each of the six experiments, ensilage temperature was controlled at 15℃, 28℃ and 35℃. The effect of the ensilage temperature on the disappearance of nitrate during ensilage was investigated. 1. It was clearly observed that nitrate contents of the silages were more markedly effected by ensilage temperature in the unwilted silages of experiments 1-3 than in the wilted silages of experiments 4-6. In the unwilted silages, large amounts of nitrate remained in the silages at 15℃ and considerable amounts of nitrate disappeared in the silages at 35℃. The silage of 28℃ showed the same trend as in the silage at 35℃. There was, however, one case where large amounts of nitrate remained in the silages. In the wilted silages, the decrease in nitrate contents was not different in three temperature levels. About 31% to 62% of nitrate contents disappeared. There was, however, one case where nitrate contents in the silages extremely remained at 15℃ and considerably disappeared at 28℃. 2. The difference in the effects of ensilage temperature was more clearly observed in the unwilted silages than in the wilted silages. The silages prepared at 15℃ were of very high quality with large amounts of lactic acid, little acetic acid and little VBN. Moreover, butyric acid was not formed in these silages. The quality of the silages at 28℃ and 35℃ were slightly poorer than that of the silage at 15℃. In the wilted silages, the quality of silages became good or middle grade without regard to the ensilage temperature.

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The tick fauna and seasonal fluctuation of the population density of the tick, Haemaphysalis longicornis Numann, have been investigated for five years in Kawatabi farm of Tohoku University. 1. Two species of Ixodes (I. nipponensis and I. ovatus) and two of Haemaphysalis (H. longicornis and H. flava) were found out in the grazing pasture and on the cattle. The species of ticks collected were almost H. longicornis. Five species of Ixodes (I. nipponensis, I. ovatus, I. tanuki, I. sp. NS and I. sp. LY) and two of Haemaphysalis (H. longicornis and H. flava) were found out on the wild animals trapped in the grazing pasture and its outside areas. The species composition of the ticks collected from the wild animals was 65% of H. flava and 10% of H. longicornis in the outside of grazing pasture, and was 96% of H. longicornis in the grazing pasture. 2. The peak of seasonal fluctuation of the population density of the tick, H. longicornis, in the grazing pasture appeared in the following order ; Nymph・Adult→Larva and the active period of the ticks were approximately synchronized with the grazing season of the cattles. The population density of the tick in the native pasture was higher than that in the sown pasture throughout the grazing season. Furthermore, we pointed out that the population density of the tick was closely related with behavior of grazing cattle as a host animal, vegetation of pasture and condition of climate.

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Denitrification is one of the important factors in nitrogen loss from cultivated land as well as removal of harvesting plants, surface run-off, leaching through the soil profile and volatilizations. Grasslands are distributed in wide environmental ranges of soil water and accumulate a large amount of organic matter such as dead roots, fallen leaves. Therefore, the grassland has a possibility to bring on a transient denitrification when the anaerobic conditions areestablished by rainfall or carbon dioxide gas evolved from microbial respiration. This experiment shows the denitrification that actually takes place in the grassland by detecting N_2O gas evolved with the introduction of C_2H_2 into the denitrifying system.

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