ETc 손실을 보상하는데 필요한 물의 양을 작물 용수 요구량(Crop water requirement, CWR)로 정의되며, ETc 평가는 작물 필요 요구량을 정확하게 정량화하는 데 필요하며, 물 균형 계산에서 중요한 역할을 한다. 토마토와 파프 리카의 실제 관수 요구량(Actual crop water, ACW)이 적절한 CWR인지 평가하였다. 토마토와 파프리카 재배에 적정한 AWC 예측 및 추정을 위하여 온실 내부 환경데이터를 Penman-Monteith을 이용하여 기준 작물 증발산(ET)을 계산한 후, 기준 증발산은 작물 상수(Kc;토마토-1.15, 파프리카-1.05)계수로 조정하였다. 토마토와 파프리카의 CWR과 ACW를 계산하여 비교 평가한 결과 ACW가 CWR을 대체할 수 있지만 파프리카의 ACW는 필요 이상으로 높게 나타났다. 또한, 토마토의 ACW는 1일 100 ~ 1,200 ml이고, 파프리카의 ACW는 1일 100 ~ 500 ml가 적절한 것으로 나타났다. 그러나, 스마트 온실에서 ETc의 정밀도를 높이려면, ETc가 CWR로 변환되고 ACW와 비교하기 위해서 클래스 A팬 설정이 필요하다. 향후 실시간으로 CWR을 측정하기 위한 시뮬레이션 프로그램 연구가 필요하다.
This study was conducted to determine the optimum medium and humidification period for the strawberry (Fragaria × ananassa Duch. cv. Maehyang) cutting seedling production. The cuttings were planted in coir (CO), rockwool (RW), phenolic foam (PF), and organic foam medium (OFM) with fogging treatment in 0, 3, 6, 9, or 12 days on February, 2019. And, as the field verification examination research, cuttings were planted in CO, RW, PF, and OFM, with misting treatment in 0, 6, 9, 12, or 15 days on June, 2019. In fogging treatments, rooting and survival rates of seedlings tended to increase with longer fogging periods, and rooting and survival rates were showed significantly higher in CO medium with more than 9 days of fogging periods. In misting treatments, rooting rate was significantly higher in CO and RW medium with more than 9 days of misting periods, and survival rate was significantly higher with more than 12 days of misting periods. There was no significantly difference by growth medium and humidification period in shoot and root growth. Therefore, when considering the rooting and survival rate the CO medium with 9 days of humidification period could be beneficial for the production of the ‘Maehyang’ strawberry cutting seedlings.
딸기는 다년생 초본성 식물로 그 과실은 영양 가치가 높고 인기있는 고부가가치 채소작물이다. 본 연구는 딸기 품종 ‘설향’과 ‘매향’의 런너유인각도(RTA)가 절간장과 런너 발생수에 미치는 영향을 조사하여 자묘의 생산성을 높이고 번식효율을 증가시키기 위한 기초 자료를 얻고자 수행되었다. 러너를 0°(상향), 45°, 90°(수평), 135°, 또는 180°(하향)의 각도로 한 달 간 유인하였다. 이 실험은 유리온실에서 주간/야간 온도 29/20°C, 평균 광도 450 μ mol m-2·s-1 PPFD의 자연광 환경에서 수행하였으며, 1일 광주기는 12시간이었다. ‘설향’과 ‘매향’에 있어서 RTA는 런너 수와 절간장에 영향을 주었으며, 자묘 수, 생체중과 건물중에 영향을 미쳤다. RTA 135° 또는 180°에서 두 품종 모두 자묘의 평균 생체중과 건물중이 가장 작았으며, ‘설향’ 품종에서는 런너 길이와 절간장이 짧아졌다. RTA가 두 품종 모두에서 런너의 직경에는 영향을 미치지 않았지만 런너의 형태에는 영향을 미쳤다. RTA중 135°와 비교해서 180°가 가장 많은 자묘를 생산하여 가장 번식효율이 좋았다.
Effect of 6kg large unit with the carton box (20% open ratio) and MA box (10,000cc·m-2·day-1·atm-1 oxygen transmission rates modified atmosphere package), and the 100g small unit with MA film on asparagus sensory quality were evaluated. The CO2 concentration depended largely on the packing unit and maintained at around 3% in small MA packages, whereas in the MA box increased to 12%. Ethylene concentration rapidly increased until after 3 days of storage in MA packages and then decreased to maintain 5μL·L-1. Unrelated to the unit size, the lower weight loss was obtained in MA packages. A significant difference in visual quality was shown since the 15th day, the best and worst were the MA box and small MA package on the finish day. Off-odor was the highest in small MA packages and the lowest in the carton box (< 3.0). Although there was no significant difference in firmness among all treatments, the packages showed the highest firmness in tips and stems, respectively. The sugar content and hue angle decreased during storage, but there was no statistical difference in all treatments. EL was lowest and highest in small MA package and carton box, respectively. On the 10th day, the total aerobic bacteria was lowest in small MA packages, but no significant difference on the 20th day. E. coli was not found in all treatments on the 10th day, while it was the lowest in the MA box on the 20th day. The mold and yeast were not observed during the whole storage. Based on the above results, the carton box packaged with 10,000cc OTR film was more effective in maintaining the quality of green asparagus with the suitable CO2 concentration for asparagus cold storage.
This study was conducted to investigate the seedling qualities and growth of paprika according to various irrigation points (Ips) (30, 40, 50, 60 or 70%) of the water contents of rockwool cube for raising seedlings of paprika. Growth degree of paprika seedlings was positively correlate with various irrigation points. In particular, paprika seedlings with IP 30-40% and IP 50-70% treatments were significantly higher than those with other treatments. Leaf area of seedlings was 50-100% wider in those with IP 50% and IP 40% treatments than those with other treatments, therefore dry weight was IP 30-60% heavier. The dry weight of more than IP 50% treatments had no significant differences. Leaf area (Y1) had a significant relation with the irrigation point (x) as Y1 = 48.311x + 133.7 (R2 = 0.9116**). Also dry weight (Y2) of the seedlings showed a linear regression equation as Y2 = 0.1584x + 0.8616 (R2 = 0.8853*). Considering the leaf area and the dry weight of irrigation points for rising seedlings of paprika in this study, the optimum range of the irrigation points in the water contents of rockwool cube is IP 50%.
The aim of this study was to investigate the effects of timing of collecting date and concentration of IBA and NAA, in order to enhance initial activity and seedling quality of domestic strawberry. Strawberry cuttings were separately taken twice, in June 7 and in July 5, and IBA and NAA were treated with the concentrations of 0.025, 0.05 and 0.1% at cutting date, respectively. The seedlings were evaluated for the percentage of survival during 18 days at 6 times after tunnel cultivation. The NAA treatment was inappropriate for strawberry cutting due to the high rate of seedling mortality, regardless of the collecting date. The vitality of the seedlings was highest at IBA 0.1% in June collecting and at IBA 0.05% in July collecting. The seedlings from June collecting had a higher quantum yield at IBA 0.1% and the seedlings from July collecting at IBA 0.05%. Therefore, IBA could be more effectively applied than NAA to promote the vitality and quality with the appropriate concentration of 0.1% at June collecting and 0.05% at July collecting, respectively.
In this study, the humidity control effect of a counter-flow ventilator was analyzed in a greenhouse with high relative humidity at night in the winter season. A case of the counter-flow ventilator was 0.96 × 0.65× 0.82(W× D × H, m) and there were heat transfer element and two fans for air supply and exhaust in the counter-flow ventilator. Two counter-flow ventilators were used in this study and the setting humidity of the ventilators was 80%. The temperature and relative humidity at night(18:00-8:00) in the greenhouse were measured. In a greenhouse without a counter-flow ventilator, the average temperature and humidity was 14.9°C, 82.8%, respectively. When the counter-flow ventilator was operated, the corresponding averages were 15.1°C, 79.9%. The independent sample t test of monthly temperature and relative humidity showed no difference in temperature, and a significant difference in relative humidity with 1% of the significance level. Therefore, using the counter-flow ventilator helps to control relative humidity in greenhouse and increase yield.. And further research considering the pros and cons of using the counter-flow ventilator is needed.
This study was conducted to provide a basis for raising farm income by increasing the yield and extending the cultivation period by creating an environment where crops can be cultivated normally during high temperatures in summer. The maximum cooling load of the multi-span greenhouse with a floor area of 504 m2 was found to be 462,609 W, and keeping the greenhouse under 32°C without shading the greenhouse at a high temperature, it was necessary to fog spray 471.6 L of water per hour. The automatic fog cooling control device was developed to effectively control the fog device, the flow fan, and the light blocking device constituting the fog cooling system. The fog cooling system showed that the temperature of the greenhouse could be lowered by 6°C than the outside temperature. The relative humidity of the fog-cooled greenhouse was 40-80% during the day, about 20% higher than that of the control greenhouse, and this increase in relative humidity contributed to the growth of cucumbers. The relative humidity of the fog cooling greenhouse during the day was 40-80%, which was about 20% higher than that of the control greenhouse, and this increase in relative humidity contributed to the growth of cucumbers. The yield of cucumbers in the fog-cooled greenhouse was 1.8 times higher in the single-span greenhouse and two times higher in the multi-span greenhouse compared to the control greenhouse.
To increase the utilization of the intelligent methodology of smart farm management, estimation modeling techniques are required to assess prior examination of crops and environment changes in realtime. A mandatory environmental factor such as CO2 is challenging to establish a reliable estimation model in time domain accounted for indoor agricultural facilities where various correlated variables are highly coupled. Thus, this study was conducted to develop an artificial neural network for reducing time complexity by using environmental information distributed in adjacent areas from a time perspective as input and output variables as CO2. The environmental factors in the smart farm were continuously measured using measuring devices that integrated sensors through experiments. Modeling 1 predicted by the mean data of the experiment period and modeling 2 predicted by the day-to-day data were constructed to predict the correlation of CO2. Modeling 2 predicted by the previous day's data learning performed better than Modeling 1 predicted by the 60-day average value. Until 30 days, most of them showed a coefficient of determination between 0.70 and 0.88, and Model 2 was about 0.05 higher. However, after 30 days, the modeling coefficients of both models showed low values below 0.50. According to the modeling approach, comparing and analyzing the values of the determinants showed that data from adjacent time zones were relatively high performance at points requiring prediction rather than a fixed neural network model.
Because the inner environment of greenhouse has a direct impact on crop production, many studies have been performed to develop technologies for controlling the environment in the greenhouse. However, it is difficult to apply the technology developed to all greenhouses because those studies were conducted through empirical experiments in specific greenhouses. It takes a lot of time and cost to develop the models that can be applicable to all greenhouse in real situation. Therefore studies are underway to solve this problem using computer-based simulation techniques. In this study, a model was developed to predict the inner environment of glass greenhouse using CFD simulation method. The developed model was validated using primary and secondary heating experiment and daytime greenhouse inner temperature data. As a result of comparing the measured and predicted value, the mean temperature and uniformity were 2.62°C and 2.92%p higher in the predicted value, respectively. R2 was 0.9628, confirming that the measured and the predicted values showed similar tendency. In the future, the model needs to improve by applying the shape of the greenhouse and the position of the inner heat exchanger for efficient thermal energy management of the greenhouse.
This experiment was aimed to identify concentrations of mineral nutrients in leaf lettuce (Lactuca sativa) grown on hydroball aquaponics and in the water for growing fish by conducting two experiments. The experiment I (Expt. I) was conducted with 12 fishes (F12) with and without filter, hydroball and plants (H12 (12 fishes, hydroball), FHP12 (12 fishes, filter, hydroball, 6 plants) and HP12 (12 fishes, hydroball, 6 plants)), and the experiment II (Expt. II) was with and without plants (FH15 (15 fishes, filter, hydroball), FHP15 (15 fishes, filter, hydroball, 6 plants)). The pH level in the water of all the treatments was decreased during the growing period, and the pH and EC of the water were lower in all the treatment with plants than those without plants in both Expt. I and Expt. II. When compared with adequate nutrient concentrations for hydroponics, nitrate nitrogen (NO3-N) and phosphorus (P) concentrations in the fish growing water were higher under the FHP15 treatment in Expt. II; however, potassium (K), calcium (Ca), and magnesium (Mg) were only 16, 49, and 82% of hydroponics, representatively, and iron (Fe) was not detected. The fresh weight of lettuce harvested from the FHP15 treatment was 38 g, only a 30% of marketable lettuce yield. The T-N and P contents of the leaf tissue grown under the FHP15 treatment were close to the optimal level; however, the K, Ca, and iron (Fe) contents were less than the optimal with no deficiency symptom.
This study was conducted to investigate cucumber plants response to greenhouse environments by solar shading in greenhouse in the summer. In order to estimate heat stress reduction of cucumber plants by solar shading in greenhouse, we measured and analyzed physiological conditions of cucumber plants, such as leaf temperature, leaf-air temperature, rubisco maximum carboxylation rate, maximum electron transport rate, thermal breakdown, light leaf respiration, etc. Shading levels were 90% mobile shading of full sunlight, 40% mobile shading of full sunlight and no shading(full sunlight). The 90% shading screen was operated when the external solar radiation is greater than 650 W·m-2. Air temperature, solar radiation, leaf temperature, leaf-air temperature and light leaf respiration in the 90% shading of full sunlight was lower than those of 40% shading and no shading. Rubisco maximum carboxylation rate, arrhenius function value and light leaf respiration of the 90% shading were significantly lower than those of 40% shading and no shading. The thermal breakdown, high temperature inhibition, of 90% shading was significantly higher than that of 40% shading and no shading. Therefore, these results suggest that 90% mobile shading made a less stressful growth environment for cucumber crops.