From the environmental aspects, primary productivity of phytoplankton plays the most important role in enhancement of marine culture oyster production. This study may be divided into two branches; one is estimation of maximum oyster meat production per unit facility(Carrying Capacity) under the present environmental conditions in Kamak Bay, the other is improvement of carrying capacity from increase of primary productivity by changing the environmental conditions that cause not to form an unfavorable environment such as the formation of oxygen deficient water mass using the eco-hydrodynamic model. By simulation of three-dimensional hydrodynamic model and ecosystem model, the comparison between observed and computed data showed good agreement. The results of sensitivity analysis showed that phytoplankton maximum growth rate was the most important parameter for phytoplankton and dissolved oxygen. The estimation of mean primary productivity of Wonpo, Kamak, Pyongsa, and Kunnae culture grounds in Kamak Bay during culturing period were 3.73gC/㎡/d, 2.12gC/㎡/d, 1.98gC/㎡/d, and 1.26gC/㎡/d, respectively. Under condition not to form the oxygen deficient water mass, four times increasing of pollutants loading as much as the present loading from river increased mean primary productivity of whole culture grounds to 4.02gC/㎡/d. Sediment N, P fluxes that allowed for 35% increasing from the present conditions increased mean primary productivity of whole culture grounds to 3.65gC/㎡/d. Finally, ten times increasing of boundary loadings from the present conditions increased mean primary productivity of whole culture grounds to 3.95gC/㎡/d. The maximum oyster meat production per year and that of unit facility in actual oyster culture grounds under the present conditions were 6,929ton and 0.93ton, respectively. This 0.93ton/unit facility is considered to be the carrying capacity in study area, and if the primary productivity is increased by changing the environmental conditions, oyster production can be increased.

A study was carried out on the distribution of chlorophyll a and water quality in the dry season in Yosuhae bay and adjoining sea, Southern Korea, in July of 1994. Concentration of salinity and phosphate were lower in the outer bay than in the inner bay. While nitrate and silicate were higher in the former than in the latter. We were identified with coastal water of origin from China with the lower salinity in outer bay. The China coastal water was characteristic of high nutrients and phytoplankton biomass, such as chlorophyll a. The principal component analysis (PCA) on the analytical data proved that high density of phytoplankton biomass occurred under the condition of low salinity and high concentration of dissolved inorganic nutrients. It is thought that the thermoharine structure and biological produtions of Yosuhae bay were controlled by the China coastal water in the outer bay.

The atmospheric carbon dioxide concentration is ever-increasing and expected to reach about 600 ppmv some time during next century. Such an increase of CO2 may cause a warming of the earth's surface of 1.5 to 4.5~circC , resulting in great changes in natural and agricultural ecosystems. The climatic scenario under doubled CO2 projected by general circulation model of Goddard Institute for Space Studies(GISS) was adopted to evaluate the potential impact of climate change on agroclimatic resources, net primary productivity and rice productivity in Korea. The annual mean temperature was expected to rise by 3.5 to 4.0~circC and the annual precipitation to vary by -5 to 20% as compared to current normal climate (1951 to 1980), resulting in the increase of possible duration of crop growth(days above 15~circC in daily mean temperature) by 30 to 50 days and of effective accumulated temperature(EAT=∑Ti, Ti~geq 10~circC ) by 1200 to 1500~circC . day which roughly corresponds to the shift of its isopleth northward by 300 to 400 km and by 600 to 700 m in altitude. The hydrological condition evaluated by radiative dryness index (RDI =Rn/ ~ell P) is presumed to change slightly. The net primary productivity under the 2~times CO2 climate was estimated to decrease by 3 to 4% when calculated without considering the photosynthesis stimulation due to CO2 enrichment. Empirical crop-weather model was constructed for national rice yield prediction. The rice yields predicted by this model under 2 ~times CO2 climatic scenario at the technological level of 1987 were lower by 34-43% than those under current normal climate. The parameters of MACROS, a dynamic simulation model from IRRI, were modified to simulate the growth and development of Korean rice cultivars under current and doubled CO2 climatic condition. When simulated starting seedling emergence of May 10, the rice yield of Hwaseongbyeo(medium maturity) under 2 ~times CO2 climate in Suwon showed 37% reduction compared to that under current normal climate. The yield reduction was ascribable mainly to the shortening of vegetative and ripening period due to accelerated development by higher temperature. Any simulated yields when shifted emergence date from April 10 to July 10 with Hwaseongbyeo (medium maturity) and Palgeum (late maturity) under 2 ~times CO2 climate did not exceed the yield of Hwaseongbyeo simulated at seedling emergence on May 10 under current climate. The imaginary variety, having the same characteristics as those of Hwaseongbyeo except growth duration of 100 days from seedling emergence to heading, showed 4% increase in yield when simulated at seedling emergence on May 25 producing the highest yield. The simulation revealed that grain yields of rice increase to a greater

This study was undertaken in order to examine the effects of inter-stimulus interval and accuracy demands of primary task on the psychological refractory period. Subjects consisted of six male right-handed voulunteers with a mean age of 25 years graduate students who performed on a double stimulation task . A 3×2(inter-stimulus interval×target size) within subjects design was used for this study. As predicted, as the ISI was increased RT₂ progressively shortened, and the delay in RT₂increased as the target size reduced. The noted decrease in magnitude of RT₂ delay as ISI(inter-stimulus interval) increased would be consistent with prediction of single channel theory. Further, the finding that RT for the small target movement was larger than that for the large target movement suggest that the small target required increased attention, perhaps because of the additional planning and control necessary to hit it. Thus a slower RT₂ indicated increased capacity being devouted to the primary task. The results also showed that the interval between the two responses decreased as the time between stimuli decreased. The implications of these findigs are discussed in terms of single channel hypothesis.

The primary countermeasure for environmental stresses of crops grown in Korea would be to maintain top soil content of available B for upland crops and Si for low land rice in balance with other nutrient elements such as N, P and K, so as to maintain those nutrient balances in plants. Development of standard levels of elements in soils for balances uptake of those elements by plants are needed under the multi nutrient factor balance concept using the soil test results.

한국의 기후에 적응성이 높을 Triticale을 육성하기 위하여 조숙 밀품종 중국8001와 호밀 재래종을 촉간교잡하여 새로 육성한 P-Tcl 의 농업적 특성을 조사한 결과는 다음과 같이 1. P-Tcl의 내한성은 밀 조광보다도 강하였으며 재래종 호밀과 비슷하였다. 2. 간장은 양친인 밀과 호밀의 중간 정도인 113cm로 장간이었으며 간은 약한 편이었다. 3. P-Tcl 의 출수 성숙기는 만숙 쪽으로 초월분리되는 것으로 보였으나 출수기로부터 개화기간은 춘파형 Triticale보다는 3～7일 짧았다. 4. P-Tcl의 수량성은 밀보다 낮았으며 이것은 수수가 적고 임실비율이 낮아진데 기인되는 것으로 보였으며 앞으로 내한다수성 추파 Triticale 육성을 위하여 임성과 수수의 증가가 요구되었다.

한국의 기후에 적응성이 높은 초연, 내한, 다수성 Triticale을 육성하기 위하여 단간조숙성인 밀 품종 중국 8001(Triticale aestivum)와 내한, 내병성 재래종 호밀(S. Cereale)간의 속간교잡 F1 의 염색체배가로 8배체 Primary Triticale의 육성결과는 다음과 같다. 1. 조숙성 및 중국 8001와 (AABBDD)와 내한, 내병성 재래종 메밀(RR)간의 속간교잡 F1 의 염색체배가로 8배체 Primary Triticale(AABBDDRR)이 육성되었다. 2. 육성된 8배체 Triticale은 양친보다 형태적으로 크고 강건하였다. 특히 수장이 길고 일수영화수가 많았으나 결실율은 24% 정도로 낮았으며 수수에는 호밀에서 유래된 것으로 보이는 모용가 있었다. 3. Primary Triticale의 체세포내 염색체 행동은 규즉적이었으나 Univalent가 많았고 정상적인 분열을 보인 것은 22% 정도였다.