Availability of potato waste fluid as a medium for the culture of clover root nodule bacteria, Rhizobium trifolii, was examined. The waste fluid containing protein was more favorable for the bacterial growth than that deproteinized by heating. The bacteria showed better growth by the addition of biotin or Tween 80 to the waste fluid from which protein was previously removed by heating. The amounts of crude fat and reducing sugars consumed by the bacteria were larger in the waste fluid containing biotin or Tween 80 than in that alone.

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This experiment was carried out in order to clarify the effect of defoliation on the appearance and elongatiion of root in oats. The investigation was made on each shoot unit (leaf internode unit) after defoliation. The materials were grown in "fog-box" for convenience of root observation. The amount of root was reduced by defoliation treatment. The reduction in the amount of root was also caused by the following factors. 1. Stoppage or reduction in the appearance of root in the third shoot unit from the one in which leaf blade was expanding at the time of defoliation treatment. 2. Retardation of elongation and branching of root. 3. Retardation of root appearnace as a consequence of retardation of plant aging.

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Since productivity and root growth of Indian corn is thought to be different by cultivation conditions, the following pot and field experiments were carried out to clarify the influence of (a) nutrition and (b) ridging. (Ridging test was carried out only in the field.) 1. Influence of nutrition a) Pot cultivation : Addition of oxide phosphorus (P_2O_5) produced marked effects in pot cultivation, as shown by increased weight of leaves and stalks (top) as well as roots. Weight increase was great where heaviest applications of P_2O_5 had been made, while negligible plant weight increase was observed where N and K_2O had been added. In general pot cultivation produced heavier roots and field cultivation produced heavier stalks and leaves. b) Field cultivation : Nutrition-plot plants (top) weighed twice as much as those from control (no extra nutrition) plot. Roots of control plot plants were also only half to one-third the weight of nutrition plot ones. Where aerial roots were cut in the nutrition plot, top productivity decreased approximately 30% because of the fall of stalks. 2. Influence of ridging Top were heavier in the ridged plot, while roots were heavier where unridged. However, as ridging tended to promote fibrous root growth, so the root-system weighed less, and its absorption capacity was greater at an earlier stage. This accounts for the vigorous growth of the ridged plants. 3. Contents of nutrients in plants a) Pot cultivation : Potted plants were controlled precisely by the amount of N, P_2O_5, and K_2O which were added as nutrients. b) Field cultivation : Non-fertilization plot plants showed variation in N, P_2O_5 and K_2O contents, these elements being highest in the ridging plot. However, with fertilization, contained elements were the same in ridged and unridged plots. Also tests carried out in field showed that fairly big quantities of fertilizer were absorbed through aerial roots. Where they were cut, aerial roots revealed inconsiderable contents of three elements, N, P_2O_5 and K_2O. 4. Plant root weights correlated There were significant correlations at P-0.05 between plant and root weights, except in the case of the fertilized ridged field plot. About top and root weight, no correlations were observed between ridged and unridged plots. 5. In respect of the number of aerial roots, more roots were observed on more vigorously growing plants

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1. Chemical qualities and components of various 31 grass silages produced in Nemuro district, Hokkaido were observed and the evaluation method by ETI were examined. 2. As ETI indicates maximum TDN intake from silage by cow, difference of feeding values will be shown more clearly than TDN. Average, range and coefficient of variation of ETI were 7. 42kg, 5.03-9.37kg and 13.9%, respectively. These observations indicated that difference between the highest and the lowest ETI was very large and it was equal to maintenance requirement of TDN in cow. 3. Average, range and coefficient of variation of TDN were 60.1, 51.3-67.9 and 5.7%, respectively. 4. Highly significant correlation coefficient was observed between chemical quality and ETI. 5. ETI will be able to be used as an overall evaluation method of chemical quality and feeding value of grass silage, and also as an estimation method of TDN intake in mainly silage feeding district.

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To evaluate the efficient method of utilization of an improved grassland for grazing purpose, an attempt was made to study the effect of different grazing systems on grassland productivity. The experiment was carried out covering two grazing seasons from 1965 to 1966 using twenty two lactating cows. The productivity of grassland was estimated by milk production per hectare (ha). Four hectares of red clover and orchard grass pasture, established 3 years ago, were divided into 2 blocks of 2.0 ha each. One block consisted of 10 separated fields of 0.2 ha each as the intensive rotation grazing pasture (I), and the other was composed of 2 fields of 1.0 ha per field as the alternate grazing pasture (E). Grassland managements such as fertilization and renovation were same for both blocks. The surplus grass in each bolck was made into hay and was fed to the experimental animals in corresponding block. The number of lactating cows alotted to two systems was equal, that is, 5 pairs of Holstein cows in the first year, and 5 pairs of Holstein and a pair of Guernsey cows in the second year. The amounts of concentrates fed were at the level of 10% of milk produced in the first year and 20% for the second year. The comparison period for grazing was 154 days for the first year and 153 days for the second year. Total number of grazing cows per ha came up to 310 head for the first year and 405 head for the second year. The 4 % fat corrected milk (FCM) yield per ha was 4.9 and 4.5 tons for the I and E systems respectively in the first year, and 6.8 and 6.6 tons in the second year. Though the FCM production of cows on the I system was slightly higher than that for the E, no significant differences were observed. From this evidence it was concluded that there were no differences in the pasture productivity in terms of milk production between the intensive rotation and the alternate grazing system. When the stocking rate was intensified from 310 head per ha for the first year to 405 head per ha for the second year, average milk production per cow decreased slightly. The pasture productivity, however, in terms of FCM production per ha increased 22% and 30% above those of the first year for the I and E systems, respectively. Thus it may be concluded that the stocking intensity is a more important factor affecting the pasture productivity than the grazing system. Additional concentrate feeding of one ton per ha above the level of concentrate feeding in the first year resulted in an increase in FCM production per ha by 1.9 and 2.1 ton for the I and E, respectively. The result obtained in this study suggests that the concentrate feeding for grazing cows is suitable at the level of 20% of milk production.

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In previous reports of this series, it was suggested that the process of silage fermentation was fairly affected by the level of initial air inclusion in ensiling. This present paper further described the relation of the initial air inclusion in ensiling to the quality of silage in cases of ensiling high moisture, moderately wilted and heavily wilted Italian ryegrass chopped and unchopped respectively. The level of initial air inclusion was changed by means of ensiling each materials at three level of quantities of 600kg/m^3, 450kg/m^3 and 300kg/m^3 by air-tightening. Two kinds of treatments of unchopping and chopping were made in each level. Per cents of volumes of included air in levels of 600kg/m^3, 450kg/m^3 and 300kg/m^3 were 42.8%, 57.1% and 71.4% in the high moisture samples, 45.1%, 58.8% and 72.5% in the moderately wilted ones and 47.3%, 60.5% and 73.6% in the heavily wilted ones respectively. The quality of high moisture silage was not satisfactory in general. But it was varied according to the level of initial air inclusion and the better quality silage was obtained at the lower level of air inclusion both in unchopped and chopped groups. Chopping treatment resulted in increased contents of not only lactic acid but also butyric acid and ammoniacal nitrogen in silage at every levels of air inclusion, thus it failed to improve the quality of high moisture silage. The quality of moderately wilted silage was better than that of the high moisture in general. But it was also varied according to the level of initial air inclusion and the better quality silage was obtained at the lower level of air inclusion both in unchopped and chopped groups. Chopping treatment resulted in increased contents of lactic acid and decreased of butyric acid and ammoniacal nitrogen in silage at every levels of air inclusion, therefore the quality of silage was fairly improved in this case. The quality of heavily wilted silage was all excellent, and both the influence of level of initial air inclusion and that of chopping were scarecely observed.

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Ensiling experiments with high moisture, moderately wilted and heavily wilted Italian ryegrass were conducted for the purpose of investigating the relation of the initial air inclusion to the quality of silage in case of ensiling the materials of various levels of water soluble carbohydrates (WSC) contents. To high moisture materials glucose was added 1, 2, 3 or 4% as supplementary WSC source, and to moderately wilted and heavily wilted materials 1 or 2% respectively. The level of initial air inclusion was changed by means of ensiling each materials at three levels of quantities of 600kg/m^3, 450kg/m^3 and 300kg/m^3 by air-tightening. Results obtained were summarized as follows : 1. As WSC contents of materials increased, pH, butyric acid contents and ratios of ammonacal nitrogen to total nitrogen in silage were lowered and lactic acid contents reversely increased, therefore the quality of silage was remarkably improved. 2. The minimum level of WSC contents of materials required to obtain good-quality silage (Flieg's evaluation point was higher than 61) was about 3%, for better-quality silage (higher than 81) it was about 5%, and for best-quality silage of no butyric acid detected it seemed to be higher than 7%. 3. The quality of silage was more seriously affected by the level of initial air inclusion. at lower levels of WSC contents or higher levels of moisture contents of materials, and it was little affected at levels of higher than 7% of WSC contents or lower than 60% of moisture contents of materials. 4. Improvings of silage quality resulted from wilting and that from increasing the level_of WSC contents in high moisture materials were quite similar.

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Effects of three cutting treatments (3-week, 5-week intervals and no-cutting) on the root growth of alfalfa were investigated in relation to the persistence of this plant. In allometric formula between top- and root weight, cutting of 3-week intervals, the egression coefficient decreased to 0.88, whereas that of 5-week intervals was 1.28. Top growth of 5-week intervals, and no-cutting were mainly affected by the growth of lateral roots, but that of 3-week intervals was affected by the growth of tap root as well as lateral roots, indicating that tap root positively contributed to the top growth through the accumulation of reserve substance under severe cutting condition. Cutting depressed the formation and the growth of lateral roots, and also the percent-age and total amount of TAC in the roots. Amount of regrowth of tops after cutting had a close correlation of +0.937 to the root weight, and this root weight had a high correlation to the content of TAC in the root. This seems to indicate that root plays an important role at the time of cutting as a reservoir of TAC.

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