To study management practices suitable for the least production loss of temperate pasture under summer stress, two different cutting dates (late June and mid July) under summer stress and five different nitrogen treatment application levels (0, 100. 200,

봄철에 자라는 목초를 다른 계절의 목초와 비교하면 어떤 특성이 있는지, 또 그 시기의 칼룸질 비료의 시용이 목초의 수분 또는 마그네슘 함량에 어떤 영향이 있는가를 알아보고자 오차드그라스 (Dacctylis glomerala L.) 채초지에서 시험했는데, 그 결과는 칼륨 시용에 따른 무기질과 수분함량에 계절차이가 뚜렷하다는 것이었다 본 시험에서 봄철 (4월)에 생육하는 목초의 무기질함량은 다른 계절보다 큰 변화를 나타냈으며, 칼륨함량은 높고 마그네슘함량은

The secular and seasonal variations of visibility of 24 cities in Korea are studied statistically from 1973 to 1986. The geographical distributions of annual change patterns of visibility are also studied by means of their characteristical variations. The secular variations of visibility show that annual totals of poor visibility($lt;10㎞) days increase significantly, while that of good visibility ($gt;30㎞) days decrease remarkably. Such tendencies are quite reversal to those appearing in several large cities in the U.S.A., England and Japan. Seasonal variations of visibility can be classified into three types : type A) The visibility is maximum in winter and minimum in summer, type B) The visibility is maximum in spring and fall, minimum in summer and winter, type C) The visibility is maximum in spring and fall, minimum is summer. Geographical distributions of annual mean visibility show that the poorest visibility appears in the Kyunggi inland region(mean 15㎞), while the best visibility occurs in mountainous north Kangwon-do and Cheju island(over 25㎞).

초지에 있어서 칼리(K)의 동태 및 반구동물의 마마그네슘(Mg) 출납에 관한 연구의 한 부분으로서, 목초중 칼리 및 마그네슘 함량의 수절에 따른 변화를 알아보기 위한 시험을 봄부터 가을(4월-11월)의 기간동안 방목지와 방목지내 채초이초지(이하 채초지)에서 실시했다. 년간 2회에 걸쳐 가축의 방목을 행한 방목지에서 월별로 시료를 취한 뒤 초종별로 나누지 않고서 전 직물체(목초 및 야초)의 칼리와 마그네슘함량을 조사했으며(시험 1), 채초지에서는 방목지보

본(本) 시험(試驗)은 주요북방형(主要北方形) 목초(牧草)에 있어서 기상환경(氣象環境) 및 예취관리(刈取管理)가 Weender 성분(成分)의 합성(合成) 및 축적(蓄積)에 미치는 영향(影響)을 구명(究明)코자 1975~'79년간(年間) 한국(韓國)과 서독(西獨)에서 실시(實施)되었다. 공시재료(供試材料)는 orchardgrass(cv. Potomac, Baraula), perennial ryegrass (cv. Reveille, Semper

수수류의 광합성(光合成), 증산(蒸散), 기공저항(氣孔抵抗)과 건물수량(乾物收量)에미치는 토괴수분(土壞水分)의 영향(影響)을 구명(究明)하고자 수수(Pioneer 931), 수수×수단그라스 교잡종(交雜種)(Pioneer 988)을 포장용수량(圃場容水量)의 100, 80, 60, 40%로 조절(調節)된 대형콘크리트 폿트(길이 14m, 폭 1m, 깊이 1m)에 생육(生育) 시킨후 쾌청한 날을 택(擇)하여 초여름인 6월(月)20일(日), 6월(月

This study was conducted to analyze seasonal variations of de-icing salt ions harvested from soils and plants according to salt damage of Pinus densiflora f. multicaulis, a evergreen conifer, on roadsides. Pinus densiflora f. multicaulis was divided into three groups referred to SD, ND, and WD (serious salt damage (SD) = 71 100%, normal salt damage (ND) = 31 70%, and weak salt damage (WD) = 0 30%) based on the degree of visible foliage damage, and measured acidity (pH), electrical conductivity(EC), and de-icing salt ions (K+, Ca2+, Na+, and Mg2+) harvested from soils and plants. The results indicated that acidity, electrical conductivity, and de-icing salt ions of soils and plants were significantly affected by seasonal variation and salt damage. In addition, a strong positive liner relationship was observed in plants between the concentration of de-icing salts and salt damage in spring, while the relationship among seasonal variation and salt damage in soil were not significant. The results from this study has important implications for the management of conifer species in relation to salinity and roadsides maintenance.

Seasonal changes in the CO2 fixation rate and water-use efficiency in the leaves of six evergreen and two deciduous broad-leaved tree species on Jeju Island, Korea, were measured using a portable photosynthesis analyzer, to identify which species are most efficient in taking up CO2 from the air. The CO2 fixation rate was high in the deciduous species in spring and summer and decreased in fall, whereas it was high in the evergreen species in summer and fall and decreased in winter. The rate remained high in the deciduous tree Prunus yedoensis from spring to fall (> 7.1 μmol CO2/m2/s) and in two evergreen trees, Castanopsis cuspidata var. sieboldii and Cinnamomum camphora, in summer and fall (7.0 9.9 μmol CO2/m2/s). Therefore, these tree species fix atmospheric CO2 effectively. The water-use efficiency was higher in evergreen species than in deciduous species regardless of the season. Exceptionally, it was high in the deciduous species Zelkova serrata in spring and summer (> 100 μmol CO2/mol H2O), suggesting that Z. serrata is a useful tree for dry conditions due to its tolerance of water stress. The regressions of the CO2 fixation rate versus the evaporation rate and stomatal conductance were linear and non-linear, respectively. This suggests that the stomatal activity of leaves plays an important part in CO2 fixation of plants. In conclusion, C. cuspidata var. sieboldii, C. camphora, and P. yedoensis should be planted along roads or in urban spaces for the greening of cities and mitigation of CO2 concentrations in the air.

In this paper, for selected station of 8 clusters in East Asia (Park, 2017) more (less) warming periods than the wintertime mean warming of intra-seasonal fluctuation curves were taken and their means were computed. Long term trends and synoptic features of the mean temperature changes were examined. In most clusters, around the third of January there were less warming periods (LWP) than the mean wintertime warming. On the contrary, in February and the first and second of January there were more warming periods (MWP) than the winter mean or LWPs having a warming trend with statistical signicance. Time series of the daily Siberian High indices showed they had been weakening in February and being stagnant around late January. In most stations, the mean temperatures of MWP or LWP had large negative correlation coecients with the Siberian high intensity. is result explains the occurrences of MWPs in most clusters in February and LWPs in late January. In cluster B there were LWPs in early February due to the influence of the Aleutian Low which were strengthening in that periods. Cluster E showed different features without LWPs in late January. The cluster is considered to be affected by its plateau environment of West Yúnnán and the Tibet Plateau which prevent cold air of the lower atmosphere in Northern Asia flowing southward, and by the regional atmospheric circulation of 500hPa surface centered in this region.

In this study, the intra-seasonal fluctuation (ISF) of wintertime temperature change in East Asia was classified by a cluster analysis of complete linkage. A ISF of temperature change was defined as a difference of synthesized harmonics (1 to 36 harmonic) of daily temperature averaged for 30 years (1951~1980, 1981~2010). Eight clusters were gained from the ISF curves of 96 stations in East Asia. Regions of the cluster C, G and A1 seem to be affected by the Siberian High (SH) center, whereas the cluster A1, A2, D, B and F by the SH main pathways. Regions of the cluster E are apart from the SH main pathways and appear to be in the area of influence of other factors. Wintertime temperatures in Northwest China (clusters C, G) and Northeast China (cluster A1) were increased very largely. In most clusters, around late January there were less warming periods than the winter mean of the mean ISF of the clusters, before and after this time there were more warming periods than the winter mean.

The heat budget is investigated in the Gumi Reservoir of the Nakdong river. In warm climate season, solar radiation effects play a important role in the change of water temperature. The features of the surface heat balance are almost derived by the latent heat flux and the solar radiation flux. On the other hand, in cold climate season, change of heat stored in the water is mainly dominated by latent and sensible heat transfer between water and air, since flux of solar radiation and loss of outgoing long wave radiation balance approximately. For the annual averages, net flux of radiation, evaporation(latent heat) loss are dominant in the Gumi reservoir. The evaporation losses are dominant from spring to early winter. This means that the Gumi reservoir rolls like a lake of thermal medium or deep depth.

In this study we were to explore the seasonal variation of water temperature distributions before and after weir construction at Gumi, Chilgok, Gangjung(Goryung), Dalsung in the Nakdong River using Landsat satellite images. Relationship between in-situ water temperature and radiance values of Landsat-5, 7, 8 satellite images showed high correlation. Seasonal variation of water temperature in Nakdong River showed that the fluctuation ranges of water temperature before weir construction were larger than those after weir construction. This indicated that the variation of water temperature is due to the difference of heat storage volume by weir construction and dredging work. In particular, the water temperature after weirs construction in autumn was 4-8 times lower than that before weirs construction. Water temperature after weir construction decreased in spring and summer at the downstream of Gumi weir and Gangjung(Goryung) weir, and the upstream of Dalsung weir. In autumn and winter, the water temperature after weir construction increased in the upstream and downstream of the whole weirs except upstream of Gumi weir. Relationship between water temperature and meteorological elements (air temperature, wind speed, sunshine, radiation) showed high correlation of above 94% in air temperature, and then radiation was high correlation before and after 65%.

The seasonal variation of phytoplankton communities and its standing crops in accordance with environmental factors were investigated at Yeongrang-ho, Cheongcho-ho, Mae-ho and Hyang-ho which are located in the East coast of Korea during April to October 2011. High concentrations of T-N and T-P were observed in four lagoons due to the inflowing nutrients from farmlands and residential areas near lagoons. Nutrient salts mainly composed of nitrogen and phosphate caused the eutrophication of the lakes, leading to the robust growth of phytoplankton. During the period of investigation, 64 to 107 taxa of phytoplankton were observed in four lagoons. Diatoms were the most dominant species with high density. Non-point pollution source was estimated as the main cause of water pollution of lagoons. Trophic states of lagoons evaluated using the value of TSI and TSIKO indicated that all the investigated lagoons were in the eutrophication state.