• Korean Journal of Environmental Agriculture
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• v.2 no.1
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• pp.45-54
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• 1983

This experiment was carried out to investigate effects of dense planting on the growth and productivity in varieties of hot pepper at open field. Three varieties (Joseng jinheung, Weonkyo No. 304 and Bulam house Putgochu) were sowed on Jan. 30th and transplanted on May 12th. The planting densities used were 3,300, 5,500 and 8,300 plants per 10a. The results obtained are as follows: 1) With higher plant density, the plant shape was changed from open-type to upright-type and the yield was increased, presumably due to the increase of leaf area index. 2) LAI and SLA per unit area were increased by denser planting. Wonkyo No. 304 presented the highest LAI and the lowest SLA. 3) Dry matter weight per unit area was also increased, however the LW/SW ratio was tended to decrease on denser planting. 4) Through crop growth analysis, it was determined that CGR and NAR were increased during the early growth stages and became decreased from last June. 5) Light intensity under the canopy formed by denser planting was decreased by 40% measured at 60 ㎝ above the soil surface. The vertical distribution of fruits became concentrated the upper part of plant. Fruit yield per unit area in denser planting was increased as compared to the conventional planting. The number of fruit setting decreased. 6) Generally, no differences in yield were detected in comparison between denser planting and conventional planting harvested on Aug. 30th and Oct. 15th, respectively. But Weonkyo No. 304 increased yield by 18% in denser planting.

• Proceedings of the Korean Society of Crop Science Conference
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• 2017.06a
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• pp.241-241
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• 2017

Sweet potatoes (Ipomoea batatas (L.) LAMK.,) have been cultivated in Central and South America for about 2000 years and are now grown mainly in Asia and South America. Sweet potatoes are annual in the temperate region, but are classified as perennial in the tropical region. In 2000, the cultivation area of sweet potatoes decreased to about 16,000 ha in 2000, but the cultivation area increased slightly in recent 20,000 ha in Korea. Sweet potatoes do not show higher maximum dry matter production of 120 ~ 150g per plant, and the leaf area index (LAI), which maximizes dry matter production, is known as 3.0 ~ 4.0. As the leaf area increase, the penetration of light into the canopy becomes poor, and sufficient photosynthesis cannot be achieved in the lower leaves, on the other hand the respiration increase, which results in poor dry matter production. This study was conducted to know the responses of sweet potatoes to intensive shading treatment of 80% shading. This experiment was conducted for about 42 days from September 6, 2016 to October 18, 2016 at Gyeongsang National University Experimental Farm, Jinju, Korea. The plant canopy was shaded with black nylon 80% shade cloth suspended 1.2 m above the ground. The photosynthetic rate, stomatal conductance, chlorophyll fluorescence, SPAD and NDVI were measured in 3 replicates every 7 days after shading initiation. After the fresh weight was measured, the samples were dried at $80^{\circ}C$ in a dry oven and measured. By the 80% shading treatment, chlorophyll fluorescence of the treated plants was slightly higher than that of the control, the SPAD value was higher by 3.4 and NDVI value was higher by 0.01. However, photosynthetic rate and stomatal conductance were lower than those of the control. The stomatal conductance of the control were two times higher than those of the control and the photosynthetic rate of the control was four times higher than that of the control. In control, plant showed a tendency to steadily increase in fresh weight and dry weight. However, in the case of shading treatment, the tendency to increase in the fresh and dry weight of tuberous roots was not clear. The fresh weight of shoot showed a tendency to increase steadily while the difference between treatment and control was not large, but tended to decrease after frost.

• Journal of the Korean Institute of Landscape Architecture
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• v.52 no.2
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• pp.21-38
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• 2024

This study aims to establish an efficient street green area to improve the urban thermal environment and enhance pedestrian thermal comfort. Specifically, This study identified parameters applicable to green space planning and design, analyzed thermal environment mitigation mechanisms for each parameter, and, based on these findings, proposed methods for tree species selection and planting in green space planning and design. To achieve this, 61 papers were selected through a four-stage process from both domestic and foreign sources. The selected papers were analyzed, and the following main results were derived: In open street canyons with high stress levels due to low aspect ratios and high sky view factors(SVF), broadleaf trees with wide crown widths, low trunk heights, high leaf area index(LAI), and high crown heights were found effective in reducing heat, thereby increasing the amount and quality of shade. In contrast, in deep and narrow street canyons with relatively low heat stress due to high aspect ratios and low SVF, broad-leaved trees with narrow crown widths, high trunks, low crown heights, and low LAI were effective in reducing heat by enhancing ventilation. This study can serve as fundamental data for establishing standards for street green spaces to improve the thermal environment of street canyons and enhance thermal comfort of pedestrians. Additionally, it can be valuable when selecting the location and prioritizing street green spaces. Moreover, it is anticipated to be a foundational resource for creating guidelines for green space planning and design in response to climate change.

• KOREAN JOURNAL OF CROP SCIENCE
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• v.37 no.6
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• pp.514-520
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• 1992

Performance of direct seeded paddy rice in ridged dry soil was evaluated at different seeding methods (broadcasting, drilling, and seeding in group) and seeding rates (4, 6, and 8kg /10a). The number of maximum tillers at broadcasting and drilling of seeds was higher than that at seeding in group. At broadcasing and drilling the number of maximum tillers at seeding rate of 6kg /10a was greater than that at 4 or 8kg /10a, but at seeding in group the number of maximum tillers increased with seeding rates. Among the seeding methods there were no differences in the number of seedlings per unit area, culm and panicle lengths, and productive tiller ratio, but heading date at seeding in group was delayed by a day compared with broadcasting or drilling. At heading stage leaf area index(LAI) and dry matter production at broadcasting of seeds were higher compared with drilling and seeding in group, but light transmission ratio at drilling and seeding in group was higher than that at broadcasting of seeds. Although the number of seedlings increased with seeding rates, LAI and dry matter production at heading stage, culm and panicle lengths, and productive tiller ratio were not different among the seeding rates. There were no differences in the number of panicles and spikelets per unit area, 1,000 grain weight, yield, and harvest index among the seeding methods. The number of spikelets per panicle at seeding in group was higher, but percent ripened grains was lower compared with broadcasting and drilling. There were no significant differences in the number of panicles and spikelets per panicle and unit area, percent ripened grains, and harvest index among the seeding rates, but yield at seeding rate of 6kg /10a was higher than at 4 or 8kg /10a. There were no significant differences in tiller length, bending moment, and fresh weight of tiller among the seeding methods. Breaking strength was lower in the order of seeding in group, drilling, and broadcasting of seeds. However, lodging index was similar among the seeding rates and lodging was not occurred in the field. There was a significant interaction in the cellulose, hemicellulose, and lignin contents of culm base between seeding methods and seeding rates.

• Korean Journal of Agricultural and Forest Meteorology
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• v.17 no.4
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• pp.384-398
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• 2015

In this paper, the high-resolution Weather Research and Forecasting/Noah-MultiParameterization (WRF/Noah-MP) modeling system is configured for the Cheongmicheon Farmland site in Korea (CFK), and its performance in land and atmospheric simulation is evaluated using the observed data at CFK during the 2014 special observation period (21 August-10 September). In order to explore the usefulness of turning on Noah-MP dynamic vegetation in midterm simulations of surface and atmospheric variables, two numerical experiments are conducted without dynamic vegetation and with dynamic vegetation (referred to as CTL and DVG experiments, respectively). The main results are as following. 1) CTL showed a tendency of overestimating daytime net shortwave radiation, thereby surface heat fluxes and Bowen ratio. The CTL experiment showed reasonable magnitudes and timing of air temperature at 2 m and 10 m; especially the small error in simulating minimum air temperature showed high potential for predicting frost and leaf wetness duration. The CTL experiment overestimated 10-m wind and precipitation, but the beginning and ending time of precipitation were well captured. 2) When the dynamic vegetation was turned on, the WRF/Noah-MP system showed more realistic values of leaf area index (LAI), net shortwave radiation, surface heat fluxes, Bowen ratio, air temperature, wind and precipitation. The DVG experiment, where LAI is a prognostic variable, produced larger LAI than CTL, and the larger LAI showed better agreement with the observed. The simulated Bowen ratio got closer to the observed ratio, indicating reasonable surface energy partition. The DVG experiment showed patterns similar to CTL, with differences for maximum air temperature. Both experiments showed faster rising of 10-m air temperature during the morning growth hours, presumably due to the rapid growth of daytime mixed layers in the Yonsei University (YSU) boundary layer scheme. The DVG experiment decreased errors in simulating 10-m wind and precipitation. 3) As horizontal resolution increases, the models did not show practical improvement in simulation performance for surface fluxes, air temperature, wind and precipitation, and required three-dimensional observation for more agricultural land spots as well as consistency in model topography and land cover data.

• Journal of agriculture & life science
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• v.45 no.6
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• pp.9-19
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• 2011

This study aimed to investigate the effect of night temperature on tomato and grafted watermelon seedlings, particularly, shoot height, leaf area, stem diameter, and total dry weight and relationship among the growth parameters which are used to evaluate healthy seedling. Plants were grown at 10, 15, and $20^{\circ}C$. Leaf area index (LAI) and total dry weight of tomato seedlings weight deceased more significantly under $10^{\circ}C$ than other night temperature regimes. In grafted watermelon seedlings, shoot height increased shapely and stem diameter decreased under $20^{\circ}C$. Increasing the integral temperature, leaf area of tomato seedlings under $10^{\circ}C$ decreased and shoot height of grafted watermelon seedlings increased although temperature integrals are same. The relationships among the growth parameter were changed upon the night temperature. Stem diameters of tomato seedlings had upward tendency with increase of shoot height, but there were no significant differences among night temperature regimes. Shoot hight of grafted watermelon seedlings had no relationship with shoot height. These results indicate that shoot height and stem diameter of tomato seedlings is not appropriate for assessing seedlings quality but shoot height of grafted watermelon seedlings with stem diameter is available.

• KOREAN JOURNAL OF CROP SCIENCE
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• v.51 no.7
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• pp.599-607
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• 2006

The experiments were carried out to develop simulation model for estimating the yield of soybean in upland and paddy field condition. Field experiments were done at National Institute of Crop Science in 2005. The evaluated soybean cultivars were Taekwangkong, Daewonkong, and Hwangkeumkong. Soybean seeds were planted by hill seeding with 3-4 seeds and row and hill spacing were $60{\times}10cm$ in upland and $60{\times}15cm$ in paddy field. Seeds were sown on row (without making ridge) and on the top of ridge in upland and paddy field, respectively. Field parameters were measured yield components ($plants/m^{2}$, pod no./plant, and 100-seed weight, seed yield and growth characteristics (stem length, leaf area at each stage, and dry weight of shoot) and after measuring they were compared the relationships with seed yield and yield components and seed yield and growth characteristics. Seed yield of soybean was affected by cultivars and planting density. Seed yield was higher in upland than paddy field due to the higher planting density in upland field. The upland soybeans generally had lower 100-seed weight than that of paddy field. Seed yield of soybean in a paddy field was greatest in Taekwangkong and followed by Daewonkong and Hwangkeumkong. The harvest index of taekwangkong and Hwanggumkong was higher in upland than paddy field, however, it was higher in paddy field than upland in Daewonkong. Seed yield was greatest in Daewonkong in both experimental fields. The greatest stem length was observed in taekwangkong and Hwanggumkong (R6) in late growth stage in paddy field. Dry weight of shoot and pod, pod number, stem length, and stem diameter were higher grown in paddy field than grown in upland. Crop growth rate (CGR) of cultivars was higher in paddy field after 8 WAS(weeks after sowing) and it was greatest at 13 WAS in Daewonkong among the cultivars. In upland field, CGR was greatest in Taekwangkong and then followed by Daewonkong and Hwanggumkong during 12 and 15 WAS. There was no significant relationships between 100-seed weight and seed yield in both experimental fields. A significant positive relationship was observed between seed number and seed yield. The correlation coefficients between leaf area and shoot dry weight were about 0.8 during the whole growth stage except 5 WAS and 4-5 WAS in paddy field and upland, respectively. This experiment was done just one year and drained paddy field condition was not satisfied drained condition successfully at 7th leaf age of soybean by the heavy rain, so we suggest that the excessive soil water reduced seed yield in paddy field and the weather condition should be considered for utilizing of these results.

• Korean Journal of Agricultural Science
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• v.16 no.2
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• pp.138-151
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• 1989

In order to find the effects of seed size on the early seedling growth and yield of soybean, three soybean cultivars in Korea were investigated. Seed size was classified into large and small according to the weight and planted in pots(1/5000a) and in the field. Three soybean cultivars respresenting large, medium and small grains were Hwangkeum-kong, Kwangkyo and Bangsa-kong respectively. These cultivars were planted on June 20, 1987. 1. The plant height, stem diameter, root length and leaf area index(LAI) of the seed with large size seemed larger than the seed with small size regardless of cultivars. 2. The fresh and dry weight were different depending upon the grain sizes. The large grain had heavier fresh and dry weight than the small grains. 3. The protein consumption rate of the cotyledon of Bangsa-kong with small grain size was faster than the Hwangkeum-kong with large grain size. 4. The stem length, stem diameter and number of main stem node of the seed with large size seemed larger than the seed with small size. Large grains of Hwangkeum-kong were the highest in the number of branch node and number of node. 5. The number of pods and grains per plant of Bangsa-kong with small grain size was larger than the Kwangkyo with large grain size. 6. The yield per 10a for Hwangkeum-kong, Hwangkyo and Bangsa-kong were 226.3kg, 193.0kg and 192.8kg, respectively and they were all statistically different. The yield increases of large grains over small grains in the Hwangkeum-kong, Kwangkyo, and Bangsa-kong were 7.4%, 8.0% and 9.2%, respectively.

• KOREAN JOURNAL OF CROP SCIENCE
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• v.35 no.2
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• pp.151-155
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• 1990

A field experiment was conducted to study both the distribution characteristics of shortwave radiation in the soybean canopy and its relationship with dry matter production. The soybean 'Paldalkong' was sown with the space of 45${\times}$10cm at Suwon on May 27. 1988. The extinction coefficient of solar radiation remained constant (0.53) after full canopy was reached. The 31.9% of the incoming solar radiation was transmitted. The reflected radiation from the plant canopy increased lineary with incoming solar radiation (R$^2$=0.9346). As leaf area index become larger than 2.5. the reflected radiation showed more significant linear relationship with the differences in the radiations between incoming and transmitted radiation than incoming solar radiation (R$^2$=0.9558). The mean reflectance during the growing period was 24.7%. A significant linear relationship (R$^2$=0.9930) had been admitted between the accumulated solar radiation intercepted by the canopy and dry matter production of 'Paldalkong' until the 35th day of ripening stage. The conversion efficiency of solar radiation intercepted to dry matter of soybean was 1.45g MJ$\^$-1/.

• Proceedings of the KSRS Conference
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• 2007.10a
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• pp.243-245
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• 2007

This study was begun to classify the paddy fields by the rice varieties and to monitor the temporal change in rice growth using SAR backscatter coefficients $({\sigma}^{circ})$. For nine fine-beam mode images of Radarsat-1 SAR, a growing period time-series of backscatter coefficients was set up from April to October in 2005, and was compared with the field-measured rice growth parameters such as LAI (leaf area index), plant height, fresh and dry biomass, and water content in grain and plant for 45 parcels in Dangjin-gun, Chungcheongnam Province, South Korea. The average backscatter coefficients for early-maturing rice varieties (13 parcels) were ranged from -18.17dB to -6.06dB and were lower than for medium-late maturing rice varieties during most of the growing season. At around the heading stage (July 30) for early-maturing rice, both rice crops showed the highest backscatter coefficient values and the difference was the greatest before harvesting early-maturing rice. The temporal difference in backscatter coefficients between rice varieties was expected to play a key role to identify early-maturing rice fields. On the other hand, comparison with field-measured rice growth parameters showed that the backscatter coefficients decreased or stayed on the plateau after heading stage even though the growth of rice canopy advanced.