Stemflow (SF) is essential for water resources within forest ecosystems and can constitute up to half of the gross rainfall (GR), depending on the forest stand structures in coniferous plantations. Although numerous studies on SF yield have been reported globally for various forest types, very few studies on SF have been reported to examine the influence of forest stand structures on SF in Korea. This study aimed to quantify the relationship between SF and forest stand structures in unmanaged Japanese cypress plantations. Two study plots were established (10 m × 10 m each) in plantations with the same stem density (SD: 2500 stems ha-1) (hereafter P1 and P2). Almost all forest stand structures (canopy projection area, tree height, diameter at breast height (DBH), number of live and dead branches, and ratio of canopy length to canopy width), including canopy volume using mobile LiDAR devices, were investigated. To evaluate the efficiency of funneling rainwater for the effect of tree biomass on SF, a funneling ratio (FR) was used. The present SF ratios (20.7% in P1 and 22.3% in P2) were much higher than those reported in previous studies of various forest types in Korea (SF ratios: 0.2–5.8% with a mean of 2.0%). This is due to the interaction between the high SD and many under-canopy dead branches. Individual-scale FR was correlated with DBH (R2 = 0.43). The present stand-scale FRs (FRstand) (22.3 in P1 and 29.2 in P2) were much higher than those reported in the previous studies (FRstand: 1.0–33.3 with a mean of 7.8) because of the negative relationship between FRstand and mean DBH (R2 = 0.78, p = 0.02). Our results provide useful information for understanding changes in SF caused by forest stand structures.

시설토마토에서 사전에 해충밀도를 예찰 하지 않고 작물 정식과 동시에 적용한, 기생성/포식성 천적과 그들의 먹이원/서식처가 결합되어 있는, ‘Natural Enemy in First (NEF)’ 기술의 총채벌레와 진딧물 방제효과를 확인하였다. 처리 후 12주차에 NEF 처리구에서 총채벌레 밀도억제 효과는 천적처리구 및 관행방제구에 비해 각각 32%와 82% 더 높았다. 처리 후 진딧물의 밀도는 모든 처리구에서 낮게 유지되어 처리구간 유의성 있는 차이를 확인할 수 없었다.

해충의 예찰 없이 작물 정식 초기에 천적을 먼저 적용할 수 있는 천적-서식처 혼합적용(Natural Enemy in First; NEF)기법의 방제효과를 확인하였다. 시설 딸기에서 조사 12주차에 NEF처리구와 천적 단독 처리구에서 친환경자재 처리구 대비 각 83%, 70%의 점박이응애 밀도 억제효과를 확인할 수 있었다. 또한 예찰 없이 작물 정식 초기에 NEF를 적용한 처리구에서 천적 단독 처리구보다 3배 이상의 높은 천적 밀도를 확인하였다.

Biological control is becoming an increasingly important part of integrated pest management programs in Korea. For this reason, effective and sustainable insect pest management is a priority for many growers. And the success of biological control depends upon the use of the economical methods such as a combination of proper natural enemies and plants (banker, habitat, trap, companion, etc.). For the last nine years, we have developed simple and reliable new habitat plants system with natural enemies, and named it『Natural Enemy in First Method』that we are introducing here. Our goal was to better understand the potential for effective use of beneficial insects and their habitat plants for the management of thrips, spider mites, and aphids in greenhouses. This approach is being developed to improve biological control in various crops in Korea.

본 연구는 지속가능한 유기농업의 실천을 위하여 국내 작부체계와 농업환경에 적합한 한국형 현장적용 기법을 구축하고자 수행하였다. 본 연구의 기본 개념은 ‘Natural Enemy in First (NE가 먼저)’로 해충발생시기의 예찰 없이 주 작물을 정식함과 동시에 천적과 보조식물을 혼합 적용해서 해충발생 이전에 천적을 포장에 먼저 정착시키는 생물적 방제기법이다. 시설재배 딸기에서 칠레이리응애, 사막이리응애, 콜레마니진디벌과 천적의 서식처 3종을 주 작물의 정식과 동시에 적용한 결과, 관행방제구에 비해 80%이상의 해충 밀도억제효과를, 천적 단독처리구에 비해 3배 이상의 높은 천적의 밀도를 확인할 수 있었다. 또한 포장 환경과 천적의 방사방법에 구애받지 않고 천적의 해충 방제효과를 극대화시킬 수 있는 라인을 적용한 결과, 약제와 천적 혼합처리구에서 라인을 적용하지 않은 처리구에 비해 해충의 밀도가 급격히 감소하고, 천적의 밀도는 2배 이상 높게 유지되는 것을 확인할 수 있었다.

The beneficial effect of silicon (Si) in increasing salt stress tolerance has been observed in many plants, including the cereal crops rice, wheat, and barley. In this experiment, we examined the effect of Si on the survival and growth of torenia (Torenia fournieri L inden ex F oum) ‘ Duchess Blue and White’ cultured in vitro in the presence and absence of salt stress. Previous reports had suggested that torenia exhibited low salt tolerance. Shoot buds isolated from 16-day-old seedlings were cultured on Murashige and Skoog (MS) medium containing 0, 50, or 100 mM NaCl alone or in combination with 1.8 or 3.6 mM Si supplied as K2SiO3. Plant survival rate was significantly reduced by NaCl supplementation compared with the control. The survival rate significantly increased to 100% when 1.8 or 3.6 mM Si was added to the MS medium containing 50 mM NaCl. However, only 31% of plantlets survived when 1.8 mM Si was added to the culture medium containing 100 mM NaCl. Shoot and root lengths significantly decreased with increasing NaCl concentration in the culture medium, whereas addition of NaCl to the MS medium also significantly reduced fresh and dry weights. However, Si supplementation significantly increased fresh and dry weights under 50 mM NaCl, compared with the control. The greatest fresh and dry weights were recorded when shoot buds were cultured on MS medium containing 50 mM NaCl and 3.6 mM Si. The activities of the antioxidant-scavenging enzymes superoxide dismutase (SOD), ascorbate peroxidase (APX), and catalase (CAT), but not peroxidase (POD), were markedly higher in the presence of 50 mM NaCl than the activity of the control. When Si was added to the medium containing 50 mM NaCl, activities of SOD, POD, APX, and CAT decreased as compared with the 50 mM NaCl treatment. Thus, Si-mediated tolerance to NaCl stress was not due to increased activity of antioxidant enzymes. Although Si was not effective in increasing tolerance to high salt concentrations, such as 100 mM NaCl, the results suggested that Si supplementation could effectively enhance tolerance to 50 mM NaCl stress.

The Kojongsi persimmon peels is byproduct after production of dried persimmon. This study was conducted to investigate optimal mixing ratio of Kojonsi persimmon peels as a substrate for cultivation of Pleurotus eryngii. The primary nutritive material of substrate for Pleurotus eryngii was corncob, soybean meal, beet pulp, ground corn and bran. Five to forty percent of persimmon peels were mixed with primary nutritive materials as new substrate. The chemical properties of substrate mixed with Kojongsi persimmon peels was similar to the mixture without Kojongsi persimmon peels in T-C, T-N, C/N ratio, and other nutrients. Mycelial growth time on medium with 5 to 30% persimmon peels was similar to the control without persimmon peels as 27 days but that on medium with 40% and 50% persimmon peels was delayed for 10 days. The time of pinhead formations in medium with 5 to 30% persimmon peels was 12 days, the growth time to harvest was 6 days. These results were similar to those of the control without persimmon peels. The sizes of pileus of treatments with 5 to 30% persimmon peels were tend to be smaller compared with the control. The length of stipe of 10% persimmon peels treatment was 80 mm which was shorter than that of the control with 120 mm.

KORAD (Korea Radioactive Waste Agency, http://www.korad.or.kr) has stored slightly contaminated ascon (asphalt coated concrete mixture) that was introduced to Gyeongju repository about a decade ago waiting for a final disposal. It is believed to be mainly contaminated by radioisotope 137Cs due to impurities introduced from the outside during the ascon manufacturing process. We studied characteristics of the radioactive waste to see whether this material would be proper enough to be disposed in Gyeongju LILW repository or be other ways to reduce the disposal volume including self-disposal before its final disposal otherwise. KORAD looked into the properness of characteristics of ascon in terms of WAC (Waste Acceptance Criteria) documented by KORAD that includes general chemical and physical properties of asphalt, density, size of grains, content of organic material and possibility of existence of chelate materials that qualitatively limited to be disposed by the criteria. And other associated characteristics such as gas generation and bio degradation were also investigated. Based on the data obtained from the study, we proposed various plausible solutions in associated with operational and disposal safety and economic view points. This study will be used for KORAD’s decision on how to control and safely dispose the spent ascon within a reasonable time period. And also those experiences may be applied for other LILW issues that require treatment or conditioning of radioactive wastes in the future.