On the dip of sea horizon

The Dip of Sea Horizon, with reference to the difference of temperature of the air and the sea water, is discussed. Tables by various authorities are given, and observations made by Mr. A. Sone on board H. J. M. S. Mansyü in the area of the “Kurosio” near the south coasts of Japan in January and February of 1926 are discussed. These observations were compared with the Kohlschütter Brehmer's Table for the correction of the ,dip of sea horizon, and it was found that the difference sometimes amounts to 4', the mean of differences (tabular value — observed value)being - i ' .8 and o’ .o for high and low altitudes respectively

Relationships between Spatial Distributions of Herbage Mass and Utilization in a Pasture Progressively Grazed by Cattle

To obtain some information about the mechanisms behind the spatially heterogeneous grazing of a pasture by large herbivores, the relationships between the spatial distributions of herbage mass, herbage consumption and ingestive behavior were investigated on a bahiagrass (Paspalum notatum Flügge) pasture during a 6-day grazing period with cattle. The animals almost always consumed more herbage from locations with higher pre-grazing herbage masses, which was attributed to greater bite weights. It was suggested that the high spatial heterogeneity in the rate of defoliation was caused mainly by the spatial heterogeneity in both the bite weight and the number of visits when the mean pre-grazing herbage mass of the pasture was relatively high, and by the spatial heterogeneity in the bite weight when the mean pre-grazing herbage mass was relatively low

Two-Dimensional Monitoring of Spatial Distribution of Herbage Mass under Grazing

Spatial distribution of herbage mass (HM) was monitored two-dimensionally during the grazing season (from May to November) in a bahiagrass pasture rotationally grazed by cattle. An electronic capacitance probe was used to estimate HM in 1464 permanent positions (50 × 50 cm) whose centres formed 1.5 × 1.5 m grids in the central 90 × 34.5 m area of the pasture. The highest mean HM was in September and October, while coefficient of variation in November. The two-dimensional charting of HM showed almost stable spatial patterns throughout the grazing season, with some patches of high HM appearing and disappearing. The development of new patches was considered to be partly due to the avoidance of areas affected by newly deposited dung pats, and the extinction of patches to the grazing down of areas where dung pats were disappearing or had disappeared. It was concluded that the technique is useful for monitoring the spatial pattern of HM, herbage production and consumption, and for associating the consumption with ingestive behavior of grazing animals

The Effect of Herbage Mass of a Pasture on the Spatially Heterogeneous Grazing by Cattle

To obtain information on spatially heterogeneous grazing by large herbivores at different time scales, spatial distribution of herbage mass and rate of defoliation was investigated on a bahiagrass (Paspalum notatum Flügge) pasture grazed by cattle during 4 to 5-day grazing periods in May, August and October. Pre-grazing herbage mass (Mpre) showed decreasing mean values and increasing spatial heterogeneity with the progress of grazing in all grazing periods, while the rate of defoliation showed inconsistent changes with season. Spatial distribution of the rate of defoliation was always more heterogeneous than that of Mpre. The correlation coefficient between Mpre and rate of defoliation increased with decreasing mean Mpre on the seasonal basis. The same trends also appeared with the daily progress of grazing in August and October. However, in May when the mean Mpre was less than 40 g DM/2500 cm2, the correlation remained almost constant at significant levels. It was shown that cattle consumed more herbage from locations with greater Mpre as the mean Mpre of the pasture decreased to the critical amount (40 g DM/2500 cm2), but they did not increase their selectivity for higher Mpre locations when the mean Mpre fell below the critical amount

Ecological Effects of Solenopsis papuana on Invertebrate Communities in O'ahu Forests.

M.S. Thesis. University of Hawaiʻi at Mānoa 2018

The Effect of Progressive Grazing of a Pasture on the Spatial Distribution of Herbage Mass and Utilization by Cattle

To develop an understanding of the spatially heterogeneous grazing of a pasture by large herbivores under progressive grazing, the herbage mass, herbage consumption and ingestive behavior by cattle were monitored daily at ninety-one 50 × 50 cm permanent locations in a bahiagrass (Paspalum notatum Flügge) pasture during a 6-day grazing period. With the progress of grazing, the mean pre-grazing herbage mass over the locations decreased. Responding to this, the mean number of visits and the mean rate of biting increased, and the mean residence time and the mean rate of defoliation decreased. The pre-grazing herbage mass became more heterogeneous, whereas the number of visits and the rate of defoliation became more homogeneous, based on the coefficient of variation. The overall spatial heterogeneity was ranked: rate of defoliation \u3e number of visits ≥ residence time ≥ pre-grazing herbage mass \u3e rate of biting. The results have provided some new information about the spatially heterogeneous grazing by cattle in a monospecific grass pasture, though further analyses and studies are necessary for fully understanding the mechanisms behind the diverse responses of the spatial heterogeneity of the variables to grazing

Relationship between Exchangeable Acidity and Persistence of Orchardgrass (\u3ci\u3eDactylis glomerata\u3c/i\u3e) in Temperate Pastures under Different Management

Orchardgrass is a high productive, highly nutritive grass, but its persistence is low under acid soil condition. Therefore, to obtain the information on the effect of soil acidity on the persistence of orchardgrass in acid soil grasslands, we investigated the relationship between exchangeable acidity (y1) and orchardgrass in sown pastures. Eight temperate pastures (four cutting meadows [CMs] and four cattle grazing pastures [GPs]) were used for vegetation survey and soil samplings. Six or three line transects (50 m each) were fixed in each meadow or pasture, and measurement location (three quadrats 20 cm×20 cm in size and 50 cm apart from each other) was set along the transect at a 10 m interval. The most dominant plant species was recorded after first cut of the meadows in 2018. Soil samples were collected in the area around quadrats, at depth of 0–5 cm for measurement of y1 and other chemical properties. Orchardgrass was dominated in 78% and 37% of CM and GP, respectively. Tall fescue (Festuca arundinacea) was also dominated in 2% and 22% of CM and GP, respectively. In CM, the locations with higher y1 showed a tendency of higher frequency of orchardgrass (P\u3c 0.1) and significantly low frequency of tall fescue (P\u3c 0.05). In contrast in GP, soil y1 did not show significant relationship to the frequency of orchardgrass and tall fescue. Soil chemical properties such as pH, NO3-N, K2O, CaO and MgO show negative relationship to y1 (P\u3c 0.05) in CM or GP, although they did not show significant relationship to the frequency of orchardgrass. These results suggest that survival rate of orchardgrass increases with increase of y1, through preventing establishment of other plant species such as tall fescue under cutting condition, while this trend is not clear under grazing