• Korean Journal of Food Science and Technology
• /
• v.28 no.1
• /
• pp.72-76
• /
• 1996

Hot air drying of Lentinus edodes was studied using the microcomputer drying system that can control the drying parameters such as air temperature, relative humidity and a weight-loss of water. The physico-chemical properties of dried products were measured in order to investigate the drying characteristics. The mechanism of water movement during air drying of Lentinus edodes closely followed the Page model. That was $M-M_c/M_0-M_c\;=\;\exp\;(-0.275t^{1.154})$ at $50^{\circ}C$ and 20% RH. The free amino acids increased with increased relative humidity. The color and browning degree increased with increased air temperature and relative humidity. The rehydration rate was low when the air temperature and relative humidity were high.

• Proceedings of the Korea Water Resources Association Conference
• /
• 2017.05a
• /
• pp.458-458
• /
• 2017

증발산은 지표면으로부터의 증발이나 식물에 의한 증산에 의해 유역으로부터 물이 제거되는 주요 기작으로서, 유역 물수지 관점에서 보았을 때 강수량과 증발산량의 차이로부터 유출이나 함양되는 양을 추정할 수 있다. 제주도의 경우에는 수자원 이용량의 약 84%를 지하수에 의존하고 있으며, 한편으로 제주도의 지질학적 특성으로 인해 일정 규모 이하의 강수량은 지표유출이나 중간유출의 과정없이 대부분 지하로 침투되기 때문에, 증발산량을 정확하게 파악하는 것이 지하수 함양량의 추정과 제주도 전체 수자원 계획에 큰 영향을 주게 된다. 정확한 증발산량 파악을 위해서는 지속적인 관측과 전문적인 계측장비 등에 의한 직접적인 방법이 있으나 광범위한 유역 단위의 관측값을 확보하는 것이 현실적으로 어렵기 때문에, 물수지법, 열수지법, 공기역학적방법 및 조합방법 등의 간접적인 방법이 많이 활용되고 있다. 간접적인 방법으로 많이 활용되고 있는 Penman-Monteith 법은 일 단위 기반의 정확도 높은 증발산량을 추정할 수 있는 장점이 있으나, 작물생육단계 및 토양수분, 기상 등 많은 변수들에 대한 입력을 요구하고 있기 때문에 복잡한 모델링 과정을 수반하게 되는 단점을 내포하고 있다. 반면, Morton (1978)의 CRAE (Complementary Relationship Areal Evapotranspiration)나 Priestly and Taylor (1973)의 AA (Advection-Aridity)와 같이 잠재증발산량과 실제증발산량간의 보완관계를 이용하는 방법은 지역적인 인자 또는 가용 수분에 대한 조건없이 몇 가지 기상자료만으로 유역의 증발산량을 산정할 수 있다는 장점이 있다. 본 연구에서는 제주도 지역의 4개 하천유역(한천, 천미천, 강정천, 외도천)을 대상으로, Penman-Monteith 법을 적용한 SWAT 모델링를 통해 얻어진 유역의 실제증발산량과 잠재증발산량으로부터, 고도에 따른 기상특성을 반영하여 증발산 보완관계를 검토하였다.

• Korean Journal of Environmental Agriculture
• /
• v.35 no.3
• /
• pp.175-183
• /
• 2016

BACKGROUND: There's a long rainy season during the Summer in Northeast Asia, including Korea. Heavy rainfall during this season causes harm to tree's root, and damped injury in the pear has been continuously reported. Pear Research Institute is breeding damp resistant rootstocks and investigating their mechanisms to relieve damped damages in the pear.METHODS AND RESULTS: Seedlings of Pyrus betulaefolia and P. calleryana were divided into two groups: control and damped, respectively. Damped group was treated by constant irrigation for 77 days and control group was maintained to keep the soil moisture pressure between 0 and -10 kPa. After the treatment, we analysed trees' growth rate, chlorophyll content, amino acids and total phenolic compounds. As a result, P. betulaefolia was sensitive to damped treatment while P. calleryana did not have significant differences between the control and damped treatment. It was observed that total contents for phenolic compounds were dramatically increased in P. betulaefolia while trees' growth rate, chlorophyll b and general amino acid contents were lowered by damping treatment.CONCLUSION: In some pear cultivars, growth habit is suppressed by damped damage. Pyrus calleryana displayed tolerances to damped damage in growth rate and some organic compound contents compared to P. betulaefolia. So we recommend to exploit P. calleryana as a pear rootstock rather than using P. betulaefolia.

• Horticultural Science & Technology
• /
• v.28 no.4
• /
• pp.529-534
• /
• 2010

Occurrence of wilted symptom in watermelon plant ($Citrullus$ $lanatus$ L.) is known to be caused by physiological disorder. The symptom results in the loss of fruit production and thus the economical loss of watermelon growers. The incidence of symptom is often found from the middle of March to the end of May in the major watermelon crop production areas of Korea (i.e. Uiryeong, Gyeongnam (lat $37^{\circ}$56'64"N, long $126^{\circ}$99'97"E)). Despite of extensive information about the physiological disorder, little study has been conducted to understand a relationship between the wilted symptom and accompanying environment factors (e.g. temperature). This study aimed to investigate effects of environmental conditions amended by a forced-ventilation system on physiological characteristics of watermelon and incidence of the wilted symptom. Watermelon plants were grown from January to May, 2009 with either the forced-or natural-ventilation treatment in a greenhouse located in the Uiryeong. In the result, the forced-ventilation treatment decreased the air, leaf and root-zone temperature approximately $4.5^{\circ}C$, $5^{\circ}C$ and $3^{\circ}C$, respectively, compared to the natural-ventilation. The fruit growth rate was maximized twice during the entire growing period. The higher rate of fruit growth was observed under the natural-ventilation than the forced one. Maximization of the fruit growth rate (approximately 430 g per day) was first observed by 12 days after fruiting under the natural-ventilation treatment, while the second one (approximately 350 g per day) was observed by 24 days after fruiting. The wilted symptom started occurring by 22 days after fruiting under the natural-ventilation, whereas no incidence of the symptom was found under the forced-ventilation treatment. Interestingly, the forced-ventilation lowered the fruit growth rate (approximately 320 g per day) compared to the natural one. Maximization of the fruit growth rate under the forced-ventilation was found at 4 days later than that under the natural one. This result coincided with a slower plant growth under the forced-ventilation treatment. These results suggest that the forced-ventilation slows down extension growth of fruit and plant, which may be associated with lowering leaf temperature and saturation deficit. We suggest the hypothesis that the forced-ventilation may alleviate stress of the wilted symptom by avoiding extreme water evaporation from leaves due to high temperature and thus by reducing competition between leaves and fruits for water. More direct and detailed investigations are needed to confirm the effect of the forced ventilation.

• Journal of Korean Society of Forest Science
• /
• v.105 no.1
• /
• pp.42-47
• /
• 2016

To examine the natural regeneration in the natural mixed-broadleaved forest, flowering, fruiting, seed-fall, and seed viabilities of Acer pseudosieboldianum (Ap) were investigated in Mt. Jungwang, Gangwon-do, from 2009 to 2015. The flower of Ap consisted many male and bisexual flowers on the corymb. Flowering dates are differed between sex morph in the same inflorescence. Stamens are stop growing and disappeared after pollinated pistil begin to grow in bisexual flowers, and male flowers have vestial pistil. The flowers of Ap might be pollinated by Apis mellifera, Andrenidae spp. and Syrphinae spp. Ap had some mechanism to prevent from self pollination with heterodichogamy. Mean annual seedfall of Ap was 70,780 ea/ha (ranged 310~234,840 ea/ha). Annual seedfall of Ap varied severely, and the maximum was about 760 times the minimum. Annual seed production of Ap might be to a normal distribution. Rates of damaged or decayed seeds are highest 59.3%, and those of sound seeds are 23.9%, Those of undeveloped and empty seeds are 9.2% and 7.6%, respectively. The most important factors influencing sound seed production might be the density and activities of insect pollinators and sucking pest in the flowerwing period, middle-late May. Successful regeneration of Ap might be in masting year and on the gap sites with proper conditions to germinate and grow. To understand the natural regeneration of deciduous hardwoods, further study on the characteristics of flowering and fruiting, pre- and post-dispersal seed predation, and annual variation on these factor should be needed.

• Journal of Korean Society of Forest Science
• /
• v.103 no.2
• /
• pp.153-158
• /
• 2014

To examine the natural regeneration in the natural mixed-broadlived forest, flowering, fruiting, seed-fall, and seed viabilities of Acer ukurunduense Trautv. & C.A. Mey. (AU) were investigated in Mt. Jungwang, Gangwon-do, from 2009 to 2013. The flower of AU consisited many male and bisexual flowers on the raceme (unusual panicle) and the arrangement of two sex morphs are differed for each inflorescence. Flowering dates are differed between sex morph in the same inflorescence. Stamens are stop growing and disappeared after pollinated pistil begin to grow in bisexual flowers, and male flowers have vestial pistil. The flowers of AU might be pollinated by Apis mellifera, Thyris fenestrella seoulensis, Cerambycidae sp., Andrenidae sp. and Ctenophora sp., and had some mechanism to prevent feom self pollination. The number of flower buds per inflorescence is 189 on June 8, and that of young samaras per inflorescence is 41.2 on June 21. At last ripened samaras per inflorescence is reduced 33.4 on September 5. Mean annual seedfall of AU was 6,720 ea/ha (ranged 670~17,930). Rates of sound seeds are highest 43.2%, and those of damaged or decayed seeds are 41.8%,. Those of undeveloped and empty seeds are 10.2% and 4.8%, respectively. Successful regeneration of AU might be in masting year and on the gap sites with proper conditions to germinate and grow. To understand the natural regeneration of the species, Genus Acer, further study on the fruiting habit, pre- and post-dispersal seed viability, and annual variation on these factor should be needed.

• KSCE Journal of Civil and Environmental Engineering Research
• /
• v.14 no.3
• /
• pp.655-668
• /
• 1994

Conventional deodorization filters using soil and compost reach the capacity limitation of deodorization in short period, because its removal mechanism primarily depends on adsorption. Therefore, in this study the experiment was performed on the removal of ammonia which is a strong inorganic malodor, frequently emitted from night soil treatment plants and sewage treatment plants, by seeding activated sludges on the bio-peat containing higher organic contents, water conservation capacity, permeability and lower pressure drop. As a result, in raw peat filter natural ammonia outlet was observed in consequence of pH increase resulted from ammonia ionizing in liquid phase. Ammonia removal mechanism primarily depended on the adsorption onto the anion colloidal substances in peat. In peat bio-filter, theoretical ammonium salts ratio was higher than that of raw peat, resulted from slight pH increase by microorganism activity, however, the experimetal value of ammonia-nitrogen accumulated in bio-peat was lower than that of raw peat because of nitrification by nitrifying bacteria. In the initial reaction period, adsorption was predominant in the ammonia removal mechanism, but nitrification was conspicuous after the middle period. Mass balance of nitrogen was established using experimental data of input $NH_3$ loading, output $NH_3$ loading, $NH_4{^+}$-N, $NO_x$-N, and Org-N. The critical time of unsteady state, which is the maximum activating point of microorganism in bio-filter, was determined using experimental data, and the ammonia adsorption curve was computed using regression analysis. On the basis of the results obtained by above analysis, the delay days for the saturation of adsoption capacity in peat bio-filter was calculated.

• Korean Journal of Agricultural and Forest Meteorology
• /
• v.11 no.4
• /
• pp.151-161
• /
• 2009

Configuration of soil hydraulic property is an essential component to understand the hydrological processes at the hillslope scale. In this study, we investigated temporal variations in pore development and soil hydraulic properties during the period from March to October in 2008. Characteristics for macropore flow and hydraulic conductivity were measured at two hillslopes: one is the hillslope located at the Buprunsa in Sulmachun watershed, and the other is the hillslope located in Gwangneung Research Forest. Vertical fluxes through macropore were measured using a tension infiltrometer at the depth of surface. The saturated hydraulic conductivities in March, June, July and September were relatively high compared to those in May and October. Temporal variations in several soil hydraulic features could be explained by the differences in vegetation activity and soil moisture content determined by antecedent precipitation. Particularly, the features of macropores had a substantial impact on hydraulic conductivity in the forest hillslope. The temporal nonuniformity of the soil hydraulic properties observed in this study manifests the dynamic features of hydrological processes in the hillslope scale and the experimental results will be useful to understand the internal hydrological processes in the mountainous hillslope.

• KOREAN JOURNAL OF CROP SCIENCE
• /
• v.38 no.4
• /
• pp.371-376
• /
• 1993

This experiment was conducted to elucidate the salt tolerance mechanism of crop plants. Plants used in this experiment were rye, barley, Italian ryegrass. Seeds were treated at saline condition and the saline conditions were controlled by NaCl. The results were summerized as follows. In rye, germination ratio and speed were above 90% and 80% at NaCl concentrations below 0.5% but germination ratio was seriously decreased at NaCl concentration above 0.6%. In barley germination ratio was not less than 80% at NaCl concentration below 0.8%. In italian rye grass germination ratio was decreased gradually by increasing NaCl concentration but germination speed was seriously decreased at NaCl concentration above 0.6% as not more than 7.5%. Water absorption rate was low in barley than rye and it was decreased by increasing NaCl concentration and duration of absorption. In barley, carbohydrate content was decreased slightly in response to increased NaCl concentration and content of reducing sugar was independent of NaCl concentration. In rye, reducing sugar content was increased until 0.3% of NaCl and increased seriously after 20 hours. $\beta-Amylase activity was high at control and 0.6% lot of NaCl, but it was not general tendency.

• Journal of Korean Society of Forest Science
• /
• v.105 no.3
• /
• pp.303-308
• /
• 2016

To investigate the effect of calcium chloride ($CaCl_2$) using for deicing salts in winter on gas exchange and stomatal responses of 3-year-old Prunus serrulata, we treated twice (1 L) $CaCl_2$ solution (0.5%, 1.0% and 3.0%) in the root zone before leaf unfolding. Stomatal conductance ($g_s$), photosynthetic rate ($P_n$), transpiration rate ($T_r$) and water use efficiency (WUE) in the leaves of P. serrulata were decreased with increasing of $CaCl_2$ concentration. Even though stomatal conductance and photosynthetic rate were reduced by $CaCl_2$, intercellular $CO_2$ concentration ($C_i$) in $CaCl_2$ treatments has similar or higher values compared with control. These results suggest that non-stomatal limitation as well as stomatal limitation induced the reduction of photosynthetic rate together. On the other hands, treatment of $CaCl_2$ before leaf unfolding also affected leaf morphology traits. We proposed that reductions of stomatal length and leaf size and high pore density with increasing salinity is adaptative mechanism to reduce the water loss in plant.