This experiment was conducted from 1964 to 1968 for the purpose of establishing an effective cropping system with grass and legume as main crops. Several types of grasses, legumes, soiling crops and common crops (dent corn, soybean, potato and rape) were grown separately for several years as the first crop on the experimental farm, each section of which was later planted with the uniform second crop of soiling dent corn. The followings are the results of this experiment: 1. Dry matter yield of orchardgrass-ladino clover mixture along with those of single H-1 ryegrass exceeded one ton per 10 ares, and were higher than the rest. Among the soiling crops, the most productive one was soiling dent corn, while potato proved to be the most advantageous of all the common crops tested. 2. Of all the second crops of soiling dent corn grown after different first crops, those grown after the single or mixed swards of legume registered highest productivity. 3. Dent corn grown after the single or mixed swards of legume had higher rate of nitrogen absorption, and the same tendency was observed for P_2O_5. However, the rate of K_2O absorption was almost the same in all cases. 4. Land previously grown with grass or legume had greater increase of soil organic matter and water stable aggregates of more than 1mm in diameter, and consequently had higher water stability as compared with the lands which were previously grown with other types of crop. Total nitrogen and total carbon content of the land previously grown with grass or legume were also higher than those of the lands previously grown with soiling crops and others. 5. Number of weeds and of their seeds found in lands previously grown with grass or legume was small and was less than 50% of that of the land previously grown with soiling crops and others.

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Since the seeding time of Italian ryegrass, as winter crop in paddy field, is limited within a short period after harvesting rice plant, it is necessary to establish the laborsaving seeding method of Italian ryegrass in order to extend its cultivating area. From this standpoint, several experiments were conducted. The results obtained are as follow: 1) The seeds sown on the soil surface marked higher rate of emergence than those covered with soil irrespective of tillage. Non-tillage sowing which is the most effective way to save labor established sufficient number of seedlings of Italian ryegrass, except the case when rainfall was insufficient to maintain soil moisture adequate for germination. 2) The worse was the seed bed condition by abbreviated preparation, the lower was the rate of seedling growth. In spite of high germination rate, non-tillage sowing effected apparently lower yield at the first cut and somewhat lower yield at the second cut than well-prepared seeding did, while the effect of land preparation on the yield after second cut was not observed. 3) Decrease in soluble nitrogen content of the soil in non-tillage plot seemed to be one of the main factors which depressed seedling growth and caused low yield at the first and second cuts. Moreover, non-tillage sowing resulted in higher percentage of solid phase and lower percentage of gaseous phase in the soil, and in severe hardness of the soil, which may also be the negative factors for yield. 4) Additional top-dressing at late autumn raised the yield of non-tillage plot up to the same level as tnat of well-prepared plot at the first cut, as the result of nitrogen supply in the soil. Consequently, additional top-dressing at late autumn can take the place of tillage to maintain the vigorous growth of Italian ryegrass seedlings. 5) It is considered that the decrease of soluble nitrogen content in the soil in nontillage plot was caused by leaching by rain-water through cracks in the soil. The cracks occur as the result of soil contraction along with evaporation of soil moisture. Therefore, the degree of running off of soluble nitrogen varies according to the factors which affect the grade of soil crack; evaporation rate of soil moisture, soil texture, rice cultivation method, etc.

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To find out the better method of the germination test of coloured guinea grass (Panicum coloratum), a few experiments were carried out on the effects of temperature, the kind of substrata and the pretreatment of seed upon the germination of the seeds. These experiments were carried out at the Seed Storage Laboratory of National Institute of Agricultural Sciences from April to July in 1970. 1. The percentage of germination at 30°〜20℃ of alternative temperature (16-8 hrs.) was significantly higher than that at 20°〜30℃. As to the substrata of germination test, the different substrata, i.e. filter paper, sand, soil and vermiculite on the germination at different temperatures were compared. At any temperature when seeds were planted in the soil and sand, the percentages of germination were higher than those planted on the moist filter paper. 2. The effects of different pretreatments of seeds, namely, the removal of the seed hull, scarification of seed, and soaking-washing with water upon the germination were compared. The removal of the seed hull proved to be a most effective treatment to increase the percentage of germination, showing a rapid and high germination rate, i.e. 80% or even higher. The treatment of scarification, soaking-washing and removal of immature seeds from mature seeds does not appear effective. 3. When seeds were treated with concentrated sulphuric acid, it was seen that the longer the treatment the higher was the percentage of germination gradually. The combination of the acid treatment and chemicals such as gibberellin and thiourea showed the most prominent effect to improve the germination.

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Experiments for investigating the mechanism of the deterioration of silage after opening silo (so-called secondary fermentation) were carried out. As the model for the above-mentioned phenomenon, silages were packed tightly in formed polystylene container immediately after taking them out from the original silos and left in a dark room with free access of air on the surface. Experiments were carreid out with eight wilted grass silages of 42〜62% moisture, which contained lactic acid and acetic acid without any higher volatile fatty acid than butyric acid. Changes in temperature of the silages in the containers varied widely ; temperature did not changed for about 4 or 10 days in some silages whereas in others it began to rise as soon as the silages were put into the container. Definite correlation between the properties of the silages and the pattern of temperature change could not be found. Chemical composition of the silages did not change as far as the temperature did not arise. On the other hand, after the rise in temperature, decrease in lactic acid and/or acetic acid content was recognized accompanied by the rise in pH value in most cases. Usually, decrease in volatile basic nitrogen and increase in protein nitrogen were found after the rise in temperature. Addition of sodium propionate prevented the deterioration in some cases but not in others. This effect was reinforced by the addition of nitrofrazone to sodium propionate, although nitrofrazone itself did not have the effect of retarding the rise in temperature.

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Experiments were carried out to make clear the relationships between seedling traits and adult ones in order to have informations about the efficient early screening methods. After seedling tests whose results had been reported in the previous paper, seedlings were transplanted to the field under 70cm by 80cm spacing. Data were taken either by eye observation or by measurement on agronomic traits such as fresh weights of the above ground parts, plant height, tillering, etc., for the succeeding two years. 1. Multiple correlation coefficients were generally not high enough for 12 seedling traits with adult fresh weights of the above ground parts. The γ value was 0.56 (p<0.01), however, for two year total of fresh weights with seedling traits on the pooled data of varietal groups in the long day treatment. Comparing the year differences, mult. cor. coeff. themselves were generally lower in the 2nd harvest year than those in the 1st harvest one, though general trend was similar between years. For day length treatment during seedling periods, mult. cor. coeff. were highest under long day treatment, followed by control and short day treatment. For varietal groups, cartain differences were detected among groups, those of Mediterranean origin having higher coefficient. 2. First canonical correlation coefficients of seedling traits vs. adult ones except fresh weights were fairly high (0.6〜0.8), the values gradually decreasing from the second to the third can. cor. coeff.. For day length treatment, highest can. cor. coeff. were recognized in long day treatment. For varietal groups, those of Mediterranean origin had highest values of the first can. cor. coeff., but differences were not consistent in the second and the third can. cor. coeff.. 3. Of seedling traits, leaf length and plant height had relatively great influences on adult traits, while others remained trivial.

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The possibility of using soluble calcium salt for pasture establishment by topdressing and oversowing (orchardgrass and Ladino clover) method was examined in the field experimeat at the shrubby land in the Grassland Research Institute, Nagoya University, Shitara-cho, Aichi-ken (Table 2). The soil was rich in humus, commonly called "kuroboku" (Table 1). The results obtained are summarized as follows: (1) The yield of herbage plants in the first year was raised by the application of calcium acetate, whereas, in the second year, the differences of herbage yield between calcium acetate application and calcium carbonate application diminished (Table 3). (2) The application of either calcium acetate or calcium carbonate improved pH (H_2O, KCl) and exchange acidity (y_1) of soil to 5cm depth but not in deeper horizones (Table 7-1, -2, -3). In the deeper horizons, however, more exchangeable calcium was present by calcium acetate application than by calcium carbonate application (Table 7-4). It was inferred from these facts that the promoting effect of calcium acetate application for pasture extablishment would be due to calcium enrichment and the reduction of alminium injury in the deeper horizons. (3) In conclusion, soluble calcium salts such as calcium acetate will be applicable in place of calcium carbonate to establish the pasture.

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The effect of evacuation or air invasion after ensiling to the quality of silage ensiled with different levels of initial air inclusion was studied. Six high moisture Italian ryegrass materials, three of which were of low water soluble carbohydrates (WSC) and the others were of high WSC, and three wilted Italian ryegrass materials were used in this experiment. The following three experimental groups were designed with each grass. In the control group, chopped grasses were ensiled in small laboratory silos of two-litre capacity at three levels of initial air inclusion of low, middle or high and the silos were sealed completely. The levels of initial air inclusion were adjusted by means of ensiling fresh grasses at three levels of quantities of 600kg/m^3, 450kg/m^3 or 300kg/m^3, respectively. In the evacuated group, the grasses ensiled in the same way as the control group were evacuated by a vacuum pump at a vacuum of 20mmHg for three minutes and the silos were sealed again. In the air invaded group, the grasses ensiled in the same way as the control group were allowed to stand unsealed for three days, then the silos were sealed. All silos were stored at 25℃ for five weeks. Lactic acid contents were reduced by evacuation at the low level of initial air inclusion. This reduction in lactic acid did not result in lowering the quality of silage both in the high moisture-high WSC grass material and the wilted one, but it was related to the deterioration of the silage quality in the high moisture-low WSC grass. Both at the middle and the high levels of initial air inclusion, lactic acid contents were increased by evacuation and the quality of silage was improved to a certain degree in every grass material. It's degree was rather higher at the high level of initial air inclusion than at the middle level and it was also higher in the high moisture-low WSC grass material than both in the high WSC and the wilted ones. Air invasion resulted in reducing lactic acid contents and increasing pH, butyric acid content and ratio of ammonical nitrogen to total nitrogen in silage at every level of initial air inclusion in every grass material. Therefore, the quality of silage was lowered to some degree in all cases. The degree was rather lower at the higher level of initial air inclusion and it was also lower in the high moisture-low WSC grass material than both in the high WSC and the wilted ones.

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Seasonal and yearly variations of estrogenic activity of alfalfa, red clover and ladino clover were investigated. All legumes were harvested at every three successive full bloom stage except the final cut at vegetative stage, on both two-years and three-years old swards. Estrogenic activity of each sample was estimated by uterine weight responses of ovariectomized immature mice. The results obtained were as follows: 1) The estrogenic activity of alfalfa was high in the spring, decreased in the summer and increased again in the fall. In the two-years old crop, estimated activity of 100gm dry matter alfalfa of the 1st, 2nd, 3rd and 4th cuttings were equivalent to 2.8, 1.7, 0.4 and 0.8μg of DES (diethylstilbestrol), respectively. Estrogenic activity of the three-years old crop was only about 1/4 of that of the two-years old crop. 2) The estrogenic activity of red clover was kept almost constant throughout the three seasons and estimated activity of dry matter of each cutting was equivalent to about 1.0μg of DES. The estrogenic activity of the two-years old crop was quite similar to that of the three-years old crop. 3) The estrogenic activity of ladino clover was quite low in the spring, then the activity increased progressively during the summer, reaching a maximum at the fall. In the one-year old crop, estimated activity of 100gm dry matter ladino clover of the 1st, 2nd, 3rd and 4th cuttings were equivalent to 0.4, 0.5, 0.8 and 1.5μg of DES, respectively. The estrogenic activity of the two-years old crop remained less than a half of the activity of the one-year old crop.

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