Milled wood lignins (MWL), which are considered to be in many aspects almost identical with lignins in situ, were isolated from Italian ryegrass (Lolium multiflorum LAM.) and alfalfa (Medicago sativa L.) stems and their chemical and physical properties were compared. The results of alkaline nitrobenzene oxidation, the IR and ^<13>C-NMR spectra and the methoxyl content of the MWLs indicated that Italian ryegrass and alfalfa lignins consist of guaiacyl-, syringyl- and p-hydroxyphenylpropane units and there is no considerable difference between the two lignins in the composition of these structural units. The number-average and weight-average molecular weights of the MWL determined by gel permeation chromatography were lower in Italian ryegrass than in alfalfa. Chemical and physical characteristics of forage grass and legume lignins were discussed in relation to their solubilization by hydrolytic treatments.

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1. Pasture is formed by a mosaic of herbage biomass. Such a spatial pattern of herbage biomass on pasture may be caused by the interaction between animals and vegetation. It has been theoretically and empirically demonstrated that the frequency distribution of herbage biomass weight per unit ground area under grazing conditions fits the gamma pattern, which contains two parameters indicating the distribution mean, μ, and distribution shape, p. 2. when the relationship between μ and p was empirically examined, the following linear function was observed : p=0.03142μ+0.2661 (μ: g dry weight per 0.25 m^2 ground area). When the average herbage biomass weight per unit ground area can be estimated or predicted, the p-value or the shape of the gamma distribution can be determined from this average weight through the linear function. 3. A system model for describing grazed pastures was also constructed to analyse and predict pasture productivity. This model contains the following variables : herbage biomass at a hight of more than 5 cm from the ground surface (μ), belowground plant biomass, cattle body weight, and so on. Time-dependent changes in the aboveground plant biomass can be predicted using this model. 4. By the incorporation of these two models, time-dependent changes in the herbage biomass frequency distribution can be calculated. Herbage in both the lower and upper tails of the frequency distribution curve cannot be used by cattle, because it is too short and too unpalatable for feeding, respectively. if the estimates of plant herbage biomass, μ, and the p-value are given in the above relationships, it becomes possible to predict the amount of herbage biomass available to cattle.

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Effects of allotment of nitrogen (N) application on annual dry matter yield of three timothy-legume mixtures were investigated to determine the adequate allotment for obtaining the highest yield. Three timothy varieties were used in this experiment ; Kunpu (extremely early variety) for use of three cuts, Nosappu (early) and Hokushu (late) for use of two cuts. Each of these varieties was grown with legumes in Kunpu-, Nosappu- and Hokushu mixtures, respectively. Legumes tested were red clover (Trifolium pratense L., CV. Sapporo) and white clover (Trifolium repens L., CV. New Zealand). Application rate of N fertilizer was 8 kgN/10 a/year for each mixture. Results obtained were summarized as follows: 1. Total annual yields of timothy and legumes were closely correlated with annual yield of timothy, and both yields increased with higher application rates of N fertilizer at early spring. These tendencies were shown clearly in both Nosappu and Hokushu mixtures. 2. Within a range of allotments in this experiment, the adequate allotment of N fertilizer for the highest total annual yield in each mixture was clarified as follows: Kunpu mixture was in the ratio 3:2:1 alloted for early spring, after the 1st cutting and after the 2nd cutting. Both Nosappu and Hokushu mixtures were 2 to 1 proportion for early spring and after the 1st cutting. It seems that these adequate allotments coincided with those bringing the highest annual yield of timothy. 3. The increase in the 1st cutting yield of timothy was required for raising annual yield, and this increase was intensified by high amount of N absorbtion at this cutting. From the standpoint of morphological constituents, increases of yield were associated with the increase of their heading tillers in both Kunpu and Nosappu, while with that of elongating tillers in Hokushu. Securing of these contributing tillers for each variety, therefore, was important to increase the 1st cutting yield of timothy. 4. From the results described above, under the conditions where the same annual rates of N fertilizer were applied, the adequate allotment application method of N fertilizer for the highest annual yield in each timothy-legume mixture was that more rates of N fertilizer were alloted to the 1st cutting rather than the 2nd or 3rd cutting.

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It was reported in Europe that yield and digestibility of whole-plant maize (Zea mays L.) were not affected by its grain content. This information is very suggestive to the breeding and testing programs for forage maize. However, little attention has been given to such a phenomenon in Japan. Our objectives were to compare isogenic sterile plants with fertile plants for the yield and chemical composition without injuring plant body under the same condition. Two complete sterile hybrids ([1] N28 CmsHt × A257, [2] B37 CmsHt × Pa91) were grown in 1987 at a density of 556 plants/a. Fertile plants were obtained by hand pollinations. The experimental field was isolated from other maize field to prevent uncontrollable pollination. In sterile plant plots, plants exhibited low extents in leaf drying-off, diseases, root lodging and broken stalks, and low concentration of low-digestible fraction in organic cell wall (OCW) of stover at yellow-ripe stage. Dry matter and energy yields of whole plants were not significantly different between sterile and fertile plants. In the case of B37 CmsHt × Pa91, though grain yield of its fertile plants was 12 times as much as that of sterile plants, the dry matter yield of whole plants reduced by only 14% due to sterility. The concentrations of crude protein and organic cellular contents in stover of sterile plants were greater than those of the fertile plants. The proportion of high-digestible fraction in OCW of sterile those of the fertile plants. The proportion of high-digestible fraction in OCW of sterile plant's stover was also greater than that of fertile plant's stover. The results indicate that the grain formation influences the senescence and nutritive value of stover, and the ability of stover as 'sink' to receive assimilation products is considerably great. Absence of grain causes the increases of dry matter yield and digestibility of stover.

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Influence of grain formation on quality and nutritive value of whole-plant maize silage should be cleared to improve the breeding program of forage maize. However, little attention has been given to determine quantitatively the effect of grain content in Japan. The objectives of this study were to determine effect of sterility on the chemical composition, fermentation characteristics, digestibility and nutritive value of whole-plant silage. Two complete sterile hybrids ([1] N28 CmsHt × A257, [2] B37 CmsHt × Pa91) grown at a density of 556 plants/a in 1987, and fertile plants were obtained by hand pollination in neighboring plots. The digestion trials using four goat were conducted for those whole-plant silages which were added urea to equalize protein concentration of about 12%. Grain content in whole-plant dry matter were 44.6% for fertile plant and 7.1% for sterile plants at harvest time (Yellow-ripe stage). Contents of dry matter (DM), ether extract (EE), starch, nitrogen free extract (NFE), nitrogen'cell wall free extract (NCWFE) and organic cellular contents (OCC) for sterile plants decreased and showed 75, 61, 51, 87, 72 and 77%, expressed as % against fertile plants' silage, respectively. But contents of crude protein (CP), crude fiber (CF), organic cell wall (OCW) and fiber fraction in NFE were 122, 145, 143 and 136%, respectively. The sterile silages seem to be considerably less mature than the fertile silage in relation to the chemical compositions. The contents of nitrate nitrogen, pH, composition of organic acid, Flieg's score and volatile basic nitrogen concentration in total nitrogen were similar, and did not vary between genotypes. When measured at a maintenance level of feeding, the digestibilities of DM, organic matter, EE, NFE, OCC, and NCWFE were lower for sterile silages ; 89, 90, 84, 87, 95 and 94% relative to fertile silage, respectively. Contrary to these, the digestibilities of CP, CF, OCW, and fiber fraction in NFE for sterile silages were higher than for fertile silage ; 106, 105, 110 and 118%, respectively. Consequently, digestible organic matter (DOM), TDN and DCP for sterile silages, which were obtained by oven-drying method, were 89, 87 and 128%, respectively. The similar results were obtained by using freeze-drying method. It is estimated that the decrease of 1% for grain content in whole-plant DM results only in the decrease of 0.179% for DOM and of 0.216% for TDN, using freeze-drying method. The slight decrease of nutritive values for sterility is due to the increase of its nutritive value for stover.

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The effect of inbreeding depression on forage yield in alfalfa (Medicago sativa L.) was determined with nineteen clones, which had been improved in agronomic traits at the Hokkaido National Agricultural experiment Station. the yield of S_1 progenies of parental clones relative to that of their respective F_1 progenies (YS_1/F_1) averaged 83.9%. There were positive correlations between allelic interaction effect and specific combining ability effect or yield of F_1 progenies, indicating that the yield of clones and their F_1 progenies are affected by the multiple allelic interaction. On the other hand, these clones differed greatly in response to selfing, with YS_1/F_1 ranging from 58.7 to 111.6%. A few clones produced S_1 progenies which outyielded the average of their respecsive F_1 progenies, suggesting the contribution of favorable additive effect of alleles to the increase in yield. These results indicate that, in practical breeding program of alfalfa, selection for yield results in increase in heterozygosity and accumulation of favorable additive effect and that clones do not respond similarly to inbreeding. It is concluded that the determination of relative effectiveness of increasing heterozygosity and accumulation favorable additive effect is prerequisite for maxmizing combining ability of alfalfa.

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The occurrence of aerial tillering and its potential dispersal distance were examined for perennial ryegrass (Lolium perenne L.) in Japan. These were examined both in the intensively managed pastures for cattle and sheep both in November 1988 and 1989. Aerial tillers were frequently found in both years. Parent tillers usually had a single vegetative propagule (i.e. an aerial tiller) on their uppermost nodes. Propagules had short distances of potential dispersal, being 4.5-4.8 cm and 3.6-4.2 cm on average in 1988 and 1989, with the maximum of 15.0 cm and 15.5 cm, respectively. Considerable spatial variation was found in propagule density, ranging from 0.0-34.4/m^2 and from 0.0-57.8/m^2 in 1988 and 1989, respectively. Vegetative reproduction from aerial tillers seems to be a valuable method in maintaining the population sizes of perennial ryegrass in the sites.

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The effects of cattle dung deposition on nitrogen flow were investigated in bahiagrass pasture rotationally grazed by Holstein heifers. ND (no dung was deposited), JD (a dung pat was artificially deposited in June) and AD (a dung pat was artificially deposited in August) treatments were applied to the pasture. Measurements were done for a year after the dung deposition for each treatment. Results were as follows. 1. Dung nitrogen disappearance was slower in AD treatment than in JD treatment, mainly caused by the lower rainfall in Autumn. 2. Annual nitrogen uptake and retention by plant and grazed herbage nitrogen by heifers in JD and in AD treatments were not significantly different from those in ND treatment, while effects of dung deposition appeared in the seasonal nitrogen uptake and retention and grazed herbage nitrogen. 3. Litter nitrogen productions in the dung covered and the surrounding areas of JD and AD treatments were significantly higher than those in ND treatment. The results were discussed in relation to the characteristics of bahiagrass pasture.

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In situ digestion trial and measurement of chewing time were done to clarify the effect of ammonia treatment to low quarity roughage on eating and ruminating behavior by dairy cattle. Late cut orchardgrass (seed-setting stage) was treated with anhydrous ammonia (3% of the grass fresh matter) in a sealed vinyl sheet for 60 days. The treated samples in nylon bags were incubated in the rumen of dairy cattle for 3, 6, 12, 24 or 48 hours, and in situ dry matter disappearance was determind. Eating and ruminating time was measured for 24 hours successively with dairy cattle fed on the treated and the untreated hay. Increase of OCC, Oa and in situ dry matter disappearance was recognized to improve the nutritive value in ammonia treated hay. Difference in eating time between treated and untreated hay was not found. Ruminating and chewing time slightly decreased in ammonia treated hay compared to untreated hay. It appears that these tendencies resulted from the decrease of OCW and the consequent structural changes. Roughage value index of the treated hay was estimated to be 17 min/kg DM lower than that of the untreated hay. In previous studies, anhydrous ammonia concentration of about 3% of fresh matter was determined to improve preservation and nutritive value of moist roughage. The result of the experiment showed that 3% of anhydrous ammonia has a potential for improving the nutritive value of low quality roughage.

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The effects of genotype, medium and nature of the explant on the formation of callus and somatic embryos were examined in alfalfa. The formation of callus and somatic embryos varied considerably among cultivars and selected regenerants. The frequency of formation of somatic embryos by selected regenerants was much higher than that of existing cultivars or original cultivars from which regenerants were selected. The size of calluses on MS medium was larger than that in BO medium, but it was not significantly different from that in B5 medium. The number of somatic embryos formed on MS basal medium was higher than that on B5 basal medium. When MS basal medium was used, the highest number of somatic embryos was generated by protocol 4, in which small pieces of a callus aggregate were cultured in liquid MS medium on a gyratory shaker at 110 rpm with 0.1 mg/l NAA for 7 days before transfer to normal regeneration medium. The size of calluses induced from the central part of hypocotyl were significantly larger than that of calluses induced from the shoot apex, cotyledon or lower part of hypocotyl. Calluses induced from root tips were much smaller than those indused from other parts of explants. Interactions between explants and media or between explants and cultivars were significant. The frequency of formation of somatic embryos from the calluses induced from the shoot apex was much higher than the frequency of those induced from the petiole, cotyledon, hypocotyl or root tip in one selfed line of progeny but not in the other. From these results, it appears that genotypic background is a more critical factor for formation of somatic embryos than either the medium or the nature of the explant. Thus, selection for regenerating ability or introduction of regenerating ability from regenerant to non-regenerant seems to be indispensable to a breeding scheme by tissue culture.

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Difference of potassium (K) dynamics between grazing with sheep and cutting grasslands were investigated when three levels of K fertilizer NK : 0, LK : 7.5 HK : 27.5 kg/10a/yr, were applied to grasslands with mixed grass species. Outlines of results are as follows. 1. Dry matter (DM) yields in the cutting grassland were superior to those in the grazing grassland at the same K levels. The increases of DM yield by K application were shown in the cutting grassland but not clear in the grazing grassland 2. K concentrations of herbage in the grazing grassland were maintained at higher percentage than those in the cutting grassland at the same levels of K application. K yield of herbage in NK of grazing was higher than that of cutting, but in LK and HK, K yields of herbage in cutting was higher than those in grazing as the result of the increment of DM yield in LK and the luxuty absorption of K in HK by K application. 3. In the cutting grassland, more than K applied was absorbed by plants and removed from the grassland. On the other hand, in grazing grassland K absorbed by plants was less than K applied, and it was shown that most of K applied were accumulated in soil and residual herbage. 4. At the same K levels, exchangeable K in soil was higher in grazing than in cutting, in particular there was a remarkable difference between grazing and cutting. 5. There are two processes of K return, from urine and dead plant tissues in grazing grassland. At low K level, K return from urine will play an important role in K cycle and, in addition to this K return from herbage will be important under high K level.

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Mixed swards of alfalfa (Medicago sativa L., CV. Thor) and orchardgrass (Dactylis glomerata L., CV. Kitamidori) were established every year from 1978 to 1987, and dry matter yield of the swards were surveyed for six years, respectively. Since 1986, Verticillium wilt (V. albo-atrum REINKE et BERTHOLD) occurred, and the yield of alfalfa decreased rapidly. Alfalfa disappeared entirely in the swards established in 1982 and 1983 (Fig. 3). Effects of the disease were severer and much more destructive compared with wet-injury in August, 1981 (Fig. 1). The disease reduced total yields of the swards in three cases, that is, the 3rd year's stand established in 1986, and the 4th and 5th year's stand established in 1984 (Table 1).

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Three experiments were conducted to examine the effects of the conditions of moisture level and temperature for urea or urea plus urease treatment on the degradability of rice (Oryza sativa L.) straw in polyester bags incubated in the rumens of sheep, and to compare urea with ammonia treatment (Expt. 1), to measure the rate of urea breakdown under some ensiling conditions (Expt. 2), and to compare in more detail the effects of urea and ammonia treatment on the degradability and composition of straw (Expt. 3). Degradability was most improved when the straw was ensiled with urea at 300 g kg^<-1> of moisture level and 40℃, the effect being almost equal to that of ammonia. The addition of urease produced little further improvement. When usea was ensiled with straw at 300 g kg^<-1> of moisture level, its hydrolysis with time followed a quadratic relationship with a maximum close to Day 21 by which time 96 and 98% of urea added had hydrolysed at either room temperature or 40℃, respectively. The maximum potential degradability of straw treated with urea at 300 g kg^<-1> of moisture level increased to 704 and 749 g kg^<-1> DM, at room temperature and 40℃ respectively, compared to 649 g kg^<-1> DM for untreated controls. Similarly, rates of degradation increased to 5.6 and 6.7 %/h compared to 5.2 %/h for controls. Urea treatment produced the effects similar to those of ammonia treatment. It is concluded that urea can be an effective source of ammonia for straw treatment under optimum ensiling condition.

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The objective of this study is to compare the differences in the efficiency of water soluble carbohydrate (WSC) in silage fermentations between tropical and temperate species with different mechanical pretreatments. For this purpose Italian ryegrass (IRG : DM 13.2%, WSC 15.5% DM) and Rhodesgrass (RG : DM 18.3%, WSC 2.8% DM) using different mechanical pretreatments (6.0 cm, 1.3 cm and laceration) were ensiled in experimental laboratory silos. The WSC fractions which can be easily extracted by cold water were determined to compare the availability of WSC during the initial fermentation of silages with IRG and RG. Well preserved silage having high content of lactic acid (14.8% DM) was prepared from IRG by laceration. There was a tendency for available WSC to be released sufficiently and to be utilized efficiently in the first 10 days by laceration. On the other hand, a typical acetate silage was made from RG by laceration. Although the silage had a relatively high pH value of 4.8 and high volatile basic nitrogen (VBN) concentration of 17.6% total-nitrogen, it was a well preserved silage with no butyric acid. Because of the thick walled cells of tropical species, the proportions of residual WSC to total WSC were relatively high in the RG silages. The amount of total acid produced even in the first 5 days was far above the contribution of WSC in all treatments of RG silage. This may be due to the extensive fermentation of some substrates other than WSC.

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Phosphorus (P), calcium (Ca) and magnesium (Mg) status of prepartum and postpartum breeding beef cows and newborn calves was investigated by evaluating mineral concentrations in diets and blood plasma of cattle. The investigations were conducted at Shikoku National Agricultural Experimental Station (Kagawa) and Tsudaka Livestock Farm of Okayama University (Okayama). The cows from Kagawa were set in grazing condition or fed with hay produced in the station during the experimental period. The cows from Okayama were set in grazing condition until 30 days before the expected calving day, and after that, they were housed and supplied with soilage, silage, rice straw and concentrate. The P, Ca and Mg concentrations in hay, which was supplied to cows in Kagawa, were lower than the requirements for cows nursing calves (P: 0.22%, Ca: 0.28% and Mg: 0.21-0.22%) and the ratio of K/(Mg + Ca) in hay from Kagawa was 2.54. The P, Ca and Mg concentrations in diets from Okayama were higher than the requirements and the ratio of K/(Mg + Ca) in diets from Okayama was lower than 2.2. The plasma inorganic phosphorus (Pi) concentrations of cows from Kagawa were as high as the critical level (4.5 mg/dl) after calving, whereas those from Okayama were higher than the critical level except for 2 hours after calving. The plasma Ca concentrations of cows from both stations showed the lowest value 1 day after calving. In Kagawa, the plasma Pi and Ca concentrations of cows in third prgenancy were significantly lower than those of cows in first and second pregnancy 1 day after calving (P<0.05). The plasma Mg concentrations of cows from Kagawa were often lower than the lower limit of a normal range (1.8 mg/dl) after calving, while those from Okayama were higher than 1.8 mg/dl except for 2 days before calving. The plasma Mg concentrations of calves from Kagawa were lower than 1.8 mg/dl from 32 to 128 days after birth. It is suggested that the low plasma Pi concentrations of cows from Kagawa were caused by the low dietary P concentration in hay and that the low plasma Mg concentrations of cows and calves from Kagawa were caused by the low Mg concentration and high ratio of K/(Mg + Ca) in hay. The decrease of plasma Pi and Ca concentrations of cows immediately after calving was likely due to the drain of P and Ca by secretion of colostrum.

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Copper (Cu) and zinc (Zn) status of prepartum and postpartum breeding beef cows and newborn calves was investigated by evaluating mineral concentrations in diets and blood plasma of cattle. The investigations were conducted at the Shikoku National Agricultural Experimental Station (Kagawa) and Tsudaka Livestock Farm of Okayama University (Okayama). The cows from Kagawa were set in grazing condition or fed with hay produced in the station during the experimental period. The cows from Okayama were set in grazing condition until 30 days before the expected calving day, and after that, they were housed and supplied with soilage, silage, rice straw and concentrate. The Cu, Molybdenum (Mo) and Zn concentrations in diets from Kagawa and Okayama ranged from 5.67 to 8.60 ppm, from 0.39 to 3.02 ppm and from 24.9 to 54.3 ppm on a dry matter basis, respectively. The iron (Fe) concentration in hay from Kagawa was 245 ppm, on the other hand, the Fe concentration in pasture grass and a diet during the housing period from December to March from Okayama were 401 and 368 ppm, respectively. The plasma Cu concentrations of cows Kagawa ranged from 0.89 to 1.02 μg/ml after calving, whereas the plasma Cu concentrations of cows from Okayama were lower than the critical level (0.65 μg/ml) from 92 days before calving to 30 days after calving. The plasma Cu concentrations of calves from Kagawa and Okayama were 0.33 and 0.30 μg/ml on 1 day after birth and increased to 0.93 and 0.88 μg/ml on 8 days after birth, respectively. The plasma Zn concentrations of cows and calves from Kagawa and Okayama were higher than the critical level (0.6-0.8 μg/ml) with the exception of cows from Kagawa On 1 day after birth. It is suggested that the low plasma Cu concentration of cows from Okayama during pregnancy was likely caused by increased Cu demand of fetus under the condition of excessive Fe concentrations in the diets. Judging from the plasma Zn concentrations, Zn status of cows and calves from Kagawa and Okayama was normal.

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The effect of gradual increase in level of starch in diet from 0 to 32% on in situ cell wall (CW) digestibility of various feeds was examined by nylon bag method with 24 hr incubation in the rumen of a Japanese black steer eqquipped with rumen fistulae. Cell wall fraction isolated from eight kinds of hay with different species and cutting times, corn and sorghum silages, rice straw, and five kinds of by-products were used for the in situ digestion trial. The ruminal characteristics of the steer were of high acetate (above 60 molar %) fermentation pattern without remarkable fall of pH (5.85 at 2.5 hr after feeding) even when the diet with 32% of starch was fed. Little effect of starch was seen on CW digestibilities of forages with high CW digestibility more than 50% on 0% starch level (early-cut Italian ryegrass, early-cut orchardgrass) and those with remarkably low CW digestibility less than 40% (reed canarygrass, rice straw), while forages with the medium CW digestibilities between them showed decrease of CW digestibility by increase of starch level (late-cut Italian ryegrass, late-cut orchardgrass, Sudangrass). Corn silage and sorghum silage also decreased their CW digestibilities by increase of starch level. For by-product, however, the increase of starch level did not affect on CW digestibilities of sugar-beet pulp, wheat bran and brewer's grain, and those of corn gluten feed bean curd refuse rather increased by increase of starch level, which suggesting the digestibility of hemicellulose fraction in these feed may increase by supply of starch.

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Litter decomposition was measured with the litter bag technique in bahiagrass swards under different cutting heights. Seasonal rate of litter decomposition (SRLD) varied considerably with sward and season between 1.04 and 11.07 mg DW/g DW/day, which indicated the influence of the microclimate in sward canopy as well as the macroclimate. Although the SRLD was significantly correlated with daily total short-wave solar radiation (TSSR), daily mean air temperature (MAT), daily mean soil temperature and daily rainfall (RF), coefficients of determination were not high. The SRLD was well predictable by the equations in which (1) litter water content and MAT, or (2) aboveground plant dry weight, RF, MAT and TSSR are the variables.

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In this study some technological assessments were made about the sward surface cultivation at the sod-seeding, coverage removing by defoliations and nitrogen applications after seeding in relation to their influences on the regrowth of existing timothy and the establishment of sod-seeded red clover. 1. The partial cultivation of sward surface using slot-seeder, John Deere Powr-Till Seeder, and the whole cultivation using disk-harrow or rotary-harrow offered good seed-bed for sod-seeded red clover. The suppression effect on existing timothy by surface cultivation varied according to the cultivation methods. Since the whole cultivation gave a great suppression to the regrowth of timothy through the physical damage, the sward turned red clover dominant by the fall. On the other hand, the partial cultivation did not sufficiently suppress the growth of existing timothy and the considerably vigorous regrowth of timothy was found. Consequently, the ratio of red clover could not attain to an adequate level until second harvest of following year. 2. the temperate defoliation of the surrounding grasses after red clover sowing accelerated the growth of red clover plants, especially in the combination of sod-seeding with the partial cultivation method. The nitrogen application in the following spring decreased the ratio of red clover. The joint effect of defoliation of surrounding grasses and application of nitrogen was regarded very important as post-sowing management for promoting the establishment of red clover.

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In this paper several experiments were made in order to introduce red clover (Trifolium pratense L.) into timothy (Phleum pratense L.) dominant swards by the strip or the whole cultivation methods. 1. In experiment 1, three cultivation methods, which contained heavy cultivation and light cultivation of the whole grassland surface with rotary-harrow and the strip cultivation of grassland with Hunter Rotary strip seeder, were compared for the temporary suppression of grass and seed-bed preparation. The latter formed tilled strip of about 9 cm in width. The light cultivation and the strip cultivation offered good seed-bed for sod-seeding of red clover and temperate suppression of growing existing timothy. The heavy cultivation offered good seed-bed bat its cultivation method caused excessive suppression of grasses and resulted in clover dominated sward. 2. In experiment 2, the influence of nitrogen application (0, 4 kg/10a) at the seeding of red clover and frequency of defoliation (once, twice) after seeding on regrowth of existing timothy and establishment of red clover was examined in sward that renovated by strip cultivation method. The regrowth of existing timothy in the autumn of treated year and establishment of red clover were affected by frequency of defoliation more than above nitrogen application. Therefore, the twice defoliated plot in the second year produced significantly higher (30%) dry matter yield of red clover than in the once defoliated plot. 3. In experiment 3, red clover was introduced by two types of surface cultivation method which included the light cultivation of whole grassland surface by using of rotary-harrow or the strip cultivation of grassland surface using of Hunter Rotary Strip Seeder. The purpose of this experiment was to determine the effect of nitrogen application (0, 2, 4 kg/10a) in early spring of following year on the establishment of sod-seeded red clover. Nitrogen application of 4 kg/10a reduced the establishment of sod-seeded red clover and it was considered that suitable amount of nitrogen in establishment stage was less than 2 kg/10a. In the plots of 0 to 2 kg/10a, dry matter yield of red clover and yield of red clover plus timothy in the second year were about 500 and 1000 kg/10a, respectivly.

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