This report summarizes the study on the movement of Na, Fe, Mn, Zn, Cu, Co, and Ni in the grassland ecosystems of P. longivalvis, R. sachalinensis and S. purpurascens in Obihiro and on the ability of their surface soils to supply minor elements. 1. The Na, Mn, Co and Ni contents in the litter of R. sachalinensis were the highest of the three species but there were no significant differences of those elements between P. longivplvis and S. purpurascens. The Fe and Zn contents in the litter of S. purpurascens showed highly significant difference from each other. There was no significant difference among the Cu contents in the litter of the three species. 2. As the soil horizon goes down to H, the Na, Fe, Mn, Zn, Cu Co and Ni contents increase steadily and show maximum values at H or A_0, but exchangeable Na decreases and shows maximum values at H or A_0. 3. The Na, Fe, Mn, Zn, Co and Ni contents in the litter of the there species are 0.123-0.278%, 181.7-260.8ppm, 27.1-139.6ppm, 18.0-41.1ppm, 11.3-12.5ppm, 0.43-0.53ppm and 0.33-0.48ppm respectively. Therefore, in the present time three are no deficiency of minor elements in this area. 4. Annual addition of minor elements is very large in the R. sachalinensis grassland. It is medium in the P. longivalvis grassland, while the S. purpurascens grassland shows small addition. 5. Since it takes a period of about each 0.693/r, 3/r and 5/r years to release and accumulate 50, 95 and 99% of its steady state level, their estimates for Na, Fe, Mn, Zn, Cu, Co and Ni in the three grassland ecosystems are as in Table 3. 6. The models of release and accumulation of Na and minor elements on the grassland floor are expressed as the equations (1) to (14). 7. The amount of minor elements in the surface soils of those three grasslands, when put to the plow or to the harvester, may decrease to 1% of the steady state level after about 50 to 310 years.

View full abstract

1. The temperatures of fires were measured by means of iron-constantan thermocouples or chromel-alumel thermocouples. In order to prevent such electrical accidents as the electric leakage, the thermocouple wire was covered with the glassfiber tube coated with silicon of 2mm in outside diameter. The time constant of the thermocouple for air temperature measurement was about 6-8 seconds at the condition of wind velocity of 2-3m/s. In the measurement of burning temperatures, the tip of each thermocouple was located horizontally at the stipulated height. 2. The output of each thermocouple was led to 2 units of portable electoromagnetic oscillograph recorder with 14 channels. The recording apparatus were operated using the accumulator of direct current of 12 volt. 3. By means of such methods, the synchronized measurement of temperature change at ten and several points from 10cm in the ground to 2m above the ground was made possible.

View full abstract

1. Study was made on the ignitability in the electric furnace, of each organ in live state and in dead state of Zoysia, Miscanthus and Sasa. No flame ignition occured at about 350℃, and burning with flame started at 400-600℃ for every sample. In the extent of about 350-800℃ of temperature, the relation of approximately T^<3.7>t=K (K=constant: ignition index) existed between the temperature (T℃) at which the sample took to flame and the time (t sec) required in ignition. The ignition index is the value which shows the relative difficulty of combustion, which is depended upon both the water content in samples and the relative difficulty of the evaporation of water from samples. 2. As the result of the study of combustion-heat of fuel sample in each grassland, using the self-sealing bomb calorimeter, each fuel sample had the combustion-heat of 4300-4600 calories per one gram, and there was scarcely any difference due to the kind of fuel.

View full abstract

This trial was carried out to clarify chemical composition and difficulty of digestion of each tissue of sorgo forage. 1. A stem was lignified with growth in the order shown below. a. Cell membrane of protoxylem b. Cell membrane of metaxylem c. Cell membrane of vascular bundle sheath d. Cell membrane of colourless parenchyma around epidermis 2. Digestion of each tissue of the leaf and the stem became hard in the order shown below. Leaf: mesophyll, epidermis, vascular bundle. rumen. Midrib was scarcely digested in the Stem: colourless parenchyma, epidermis, vascular bundle. 3. Comparing the chemical composition of the stem with that of the leaf, the stem contained much crude fiber and lignin. The leaf contained much crude protein and crude fat. The chemical composition of each tissue of the stem compared with that of the leaf, the contents of crude fiber and lignin of the stem decreased in the order shown below. epidermis, vascular bundle, colourless parenchyma. But the order of crude protein is contrary to crude fiber anb lignin. The contents of crude protein and crude fat of the leaf decreased in the order shown below. epidermis and mesophyll, vascular bundle. But the order of crude fiber was contrary to crude protein and crude fat. 4. The value of feed of the stem was lower than that of the leaf in view of chemical composition and difficulty of digestion of each tissue.

View full abstract

The behaviors and growths of dairy heifers were studied at three levels of grazing intensity under rotational grazing with six paddocks. Diurnal behaviors were traced in spring (June 10-12), summer (August 12-15) and autum (September 17-20). Body weight of heifers were also measured at three hours intervals from 6a.m. to 6p.m. on each day. The results are summarized as follows. 1. Average herbage weights of eight rotation were 631, 970, 1251kg per 10 are and utilization percentage were 72.9, 56.8, 46.6% at heavy, moderate and light grazing intensity, respectively. Herbage of heavily grazed pasture was high in DCP and TDN contents and at all grazing intensities herbages were lowered 2.6-3.8% in DCP and 2.7-3.8% in TDN after grazing. The nutritive values of herbage were lowered in mid-summer and growths of heifers were slowered in this period. The proportion of orchardgrass was maintained higher in light grazing and perennial ryegrass in heavy grazing. 2. Average daily gains of body weightr were 434, 653 and 611g at heavy, moderate and light grazing, respectively. Average amounts of dry matter intake per animal per day were 1.94, 2.02 and 2.48% of body weight at each intensity and they tended to decrease with advancing season. 3. The time spent by heifer in grazing was longer in heavy and moderate grazing probably due to deficiency of pasture allowance, but judging from their performace this was not enough to compensate less amounts of pastures in heavy grazing. Grazing intensity had greater effects on rumination than grazing, as the time spent on rumination by heifer of heavy grazing was half that of light grazing. Animals appeared to have a dull grazing when amount of herbage was bellow the critical point and decreased their grazing time at the last day of each rotation. Behavior, especially ruminating, varied markedly by season. Then the behavioral patterns of heifers were similar at same season in spite of the differences of their grazing intensity. Rainfall of 18mm per day had little effects on their fundamental behaviors, but the proportion of lying down form markedly decreased in the rainy day. In a day, heifers had three peaks of grazing of which the peak from 9a.m. to 1p.m. was very sharp and in autumn heifers spent almost their time for grazing during this period. 4. Liveweights increased from morning to evening every day, but its maximum values were shown at the first day of each rotation. Therefore, values during afternoon decreased linearly from the beginning to the end of each rotation and seasonal growths of heifers were indicated as accumulated values of gains of each rotation, not as gains of day. From periodical liveweight changes, intake by heifers was very large in the first day of rotation and peak of grazing was only one time from 9a.m. to 12a.m. each day. Behaviors and liveweight changes suggest that heifers learned not only the periodicity of rotation but also the moveing time to the next paddck. 5. The growth of heifer had a positive correlation with the time spent on rumination, but negative correlations with the time spent on grazing and the number of drinking.

View full abstract

In order to examine the practical technique of the chromogen-chromic oxide double indicator method for estimating forage in grazing cattle, several experiments were performed and the following results were obtained. 1) Chromogens were almost completely recoverd from the dried feces by the extraction starting from one gram of sample with 3l of 35% acetone for 90 minutes continuously in a Buchner funnel. 3) There were little differences between dried and fresh feces samples in the extracting rate of chromogen and in the estimated digestibility of dry matter. 3) About 99% of supplied chromic oxide was recovered from the feces sample collected for 3 days after 8 day-prefeeding. 4) Using cows receiving 40kg of Italan ryegrass soilage, forage intake was estimated by the chromogen-chromic oxide double indicator method, and it was found that the estimated value was statistically not different from the observed one.

View full abstract

This paper proposed that the method of micro- or semimicro- diffusion analysis could be appelied for the determination of hydrocyanic acid content of plants such as Sorghum or Sudan grass and to give a reliable result for its determination. The standard procedure of determination of hydrocyanic acid in plants as follows ; The outer compartment of a diffusion unit is placed with fresh sample cut into 3×3mm, and added with a few drops of chloroform and 1 to 2ml of 0.02% sulfuric acid. Alkali picrate solution, 1.0 to 2.0ml are pippetted into the central well of unit. The unit is tightly covered with using of slightly acidified gum arabic and glycerol mixture, and then incubated at about 20〜25℃, for 12〜20hrs. The differential optical density between alkali hydrocyanic acid picrate and alkali picrate is measured at 510mμ.

View full abstract

1. The purpose of this study was to estimate the productivity of sward by the livestock performance with different grazing intensity. 2. The stocking rate tested in this study were 2.50cow/ha for control (treatment 1) and 3.125cow/hr for heavy grazing intensity (treatment 2). 3. The pastures used were 2.0ha for treatment 1 and 1.6ha for treatment 2, and both of them were divided into 4 paddocks. Five lactating cows were assigned to each treatment. The rotational grazing system was taken with a basis of the grazing condition of the control. The surplus grasses of each pasture were made in hay and were given to the cows which were fed concentrate at a rate of 20% of milk yield. 4. The daily amounts of FCM produced per cow were 14.68kg. In average for treatment 1 and 14.23kg. for treatment 2 which was 25% greater in grazing intensity than that of treatment 1. Calculated yields of FCM per hectare were 5.44t. for treatment 1 and 6.54t. for treatment 2 which was 20.2% greater than that of treatment 1. This increase shows that productivity of psasture estimated with milk yield has been influenced by heavy grazing intensity. 5. There was no significant effect of grazing intensity on milk composition and weight gains of the animals. 6. Yield of TDN per hectare in treatment 2 was.18.3% greater than that of treatment 1 (4.08t. vs. 3.45t). This result suggsts that an increase in grazing intensity improved an efficiency of a pasture utilization. 7. From the results of the past two years' studies on grazing method, it was also showed that increasing graziug intensity tended to improve the productivity per unit area of pasture, although the production per cow was slightly decreased.

View full abstract