• KOREAN JOURNAL OF CROP SCIENCE
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• v.37 no.5
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• pp.436-441
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• 1992

This study was carried out to discuss the influences of the different fertilizer levels and plant densities on the flowering and balling in cotton in Mokpo Branch Station, Crop Experiment Station in 1991. The cotton flowered 67% before Aug. 25 which is the limit date of picked-cotton harvest, and the ratio of flowering for stalk-cut cotton was 30%. The 1.5 times fertilizer levels and the 70cm row density had more flower buds, flowers and bolls per m$^2$ than any other treatment plot. The crop growing was bad in dense planting due to the nutrient deficiency. The flowering ratio to flower bud was about 70%, and the balling ratio to flower numbers was about 48%. The bolling ratio was lower in the case of more flower number. The shedding ratio of flower buds was about 30% in average and showed increasing tendency by dense planting. It was observed that the higher ratio of bud shedding tended to accompany with shedding the lower ratio of boll shedding.

• KOREAN JOURNAL OF CROP SCIENCE
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• v.25 no.3
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• pp.35-40
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• 1980

In order to evaluate the fluctuation of soybean aphid (Aphis glycines Matsumura) population, six leading soybean cultivars were planted on five different planting dates with three plant spacings. The survey of aphid population and climatical condition were made from June through September in 1978. According to the differences of planting dates and plant spacings the soybean aphid populations were varied, and varietal response to the aphid was significantly different. Counting of aphid infestation on top third trifoliolate leaf seemed to be efficient for the estimation of soybean aphid population.

• KOREAN JOURNAL OF CROP SCIENCE
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• v.25 no.2
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• pp.15-22
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• 1980

Alkali digestion value of rice kernels was increased with delayed planting date and decreased with temperature during ripening. Varietal difference in average digestion value between low and high groups of rice varieties was the greatest under the conditions of 1.4 percent solution of potassium hydroxide, early planting and day/night temperature of 30/22$^{\circ}C$ Segregation ratio of alkali digestion value in $F_2$ generation was varied with crosses showing 3:1 for nine crosses, 1:3 for one cross, 9:7 and 13:3 for two crosses respectively and non-segregation for one cross of 15 crosses between low and high varieties in the digestion value.

• KOREAN JOURNAL OF CROP SCIENCE
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• v.28 no.3
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• pp.291-298
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• 1983

The effects of various factors affacting yield and its components in rice were estimated by analzing the yield forcasting trial data from 1966 to 1979. The results obtained are as follows: 1. The year effects was increased by 3.46kg per year, and one day early planting increased by 2,26kg. 2. The effect of japonica vareties was negative while that of indica-japonica hybrid varieties was positive and the effect of each varities was increased by 3.46kg per year. 3. The contribution of each effect of the planting date, nitrogen varity, pest control and other improvement of cultivation to yield was estimated as 1.76kg (14.5%), I.04kg (8.7%), 5.84kg(48.2%), 3.47kg(28.6%) per year, respectively.

• KOREAN JOURNAL OF CROP SCIENCE
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• v.34 no.3
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• pp.246-251
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• 1989

A medicinal legume crop, Cassia tora L., was grown with four different seeding dates in 1986 field condition to find the flowering and pod setting characteristics. Initial flowering date and flowering duration were almost same between plants sown from April 20 to May 30, but those of plants seeded at June 20 were significantly delayed and shortened. Last flowering date, however, was not different between plants sown from April 20 to June 20. C. tora plants showed indeterminate flowering habit, and bloomed vigorously from fourth date after initial flowering. Numbers of flowers, ovules and pods per plant were decreased along with delaying seeding date, and ovule to flower ratio and pod to flower ratio were greatly decreased in June 20 seeding plot. Flowers bloomed on second week from initial flowering showed the highest number of ovules and pods, and flowers bloomed after early September did not develop to matured pods. Maximum values of pod length, number of seeds per pod and 1000-grain weight were obtained from flowers bloomed on second week from initial flowering of plants sown from April 20 to May 30, and first week in June 20 seeding plot.

• KOREAN JOURNAL OF CROP SCIENCE
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• v.66 no.4
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• pp.411-418
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• 2021

The yield potential of sesame depends on genetic factor, environmental factor, genetic × environmental interaction, as well as agronomic factors such as sowing date, planting density or seed rate for sowing. The main aim of this study was to analyze the effects of different sowing dates on the yield-related traits and total seed weight of sesame. The analysis of variance revealed that different sowing dates affected sesame yield-related traits such as plant height, number of branch per plant, number of capsule per plant, 1,000-seed weight, and total seed weight. Early or late sowing date showed negative effect of yield-related sesame traits and total seed weight. Optimum sowing date for sesame in the middle region of Korean peninsula was May 10^th, in which total seed yield recorded 90 kg per 10 are. Path-coefficient analysis revealed that the number of capsule per plant and plant height were major factors that affected the total seed weight of sesame across different sowing dates.

• Asian Journal of Turfgrass Science
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• v.21 no.1
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• pp.9-21
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• 2007

Research was initiated to examine establishment efficiency of zoysiagrass by plugging. Zoysiagrass is known to be a slowly establishing turfgrass species. Properly-treated zoysiagrass seed can speed up the establishment rate, while initial irrigation practice is intensively required after seeding. A planting method with small plugs($2.5{\times}2.5cm$) from seeding can overcome initial watering requirement. Establishment speed, however, can vary with planting dates, planting spaces, and plastic film cover in early stage. Establishment characteristics were investigated for two years by planting dates that were April 5, May 18, July 13, August 24 and October 29 in 2004 and April 6 in 2005. They were also compared with three different spaces($20{\times}20,\;25{\times}25,\;and\;30{\times}30cm$) and three different fertilizer levels(15, 30, and $45g\;N{\cdot}m^{-2}$). Ground coverage reached to 90% in plugs of 'Zenith' zoysiagrass planted on April 5. It increased suddenly in period of July to August, resulting in about 50% of full establishment rate. Establishment rates were significantly faster over 9% in plugs spaced at $20{\times}25cm$ than in those at $30{\times}30cm$. No significant differences were observed on the stolen number and stolen length in the study. Survival rate in zoysiagrass plug was over 90% at all plantings. These results demonstrated that zoysiagrass establishment using small plug from seeding is considered to be a safe and efficient method.

• KOREAN JOURNAL OF CROP SCIENCE
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• v.59 no.3
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• pp.299-306
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• 2014

Fresh edible sweet corns demand relatively short period to harvest fresh ears, which can allow farmers to make a choice sweet corns for various cropping systems. For this reason, we were to find the optimum planting date of late-planted sweet corns to sell fresh ears in the autumn linked to cropping system with winter crops, investigating yield and properties of marketable fresh ears and growth traits of sweet corns (cv. 'Godangok' and cv. 'Guseulok') depending on planting dates such as 10 July, 20 July, and 30 July in Suwon 2012 and 2013, respectively. The 20 July-planted sweet corns showed the most fresh ear yield. However, the 10 July-planted and the 30 July-planted had 32% less yield caused by consecutive rainfall from 10 July through 20 July, and 15% less yield due to low air temperature during ripening than the 20 July-planted, respectively. The 10 and 20 July-planted sweet corns had average 140g of a fresh ear weight and 15% heavier ear than the 30 July-planted. For the July-planted sweet corns, silking days after planting ($r=-0.80^{**}$), and harvesting days after silking ($r=-0.97^{**}$) and planting ($r=-0.91^{**}$) were highly negatively correlated with daily mean air temperature during the period, resulting in it takes 1,100 growing degree days (GDD) to harvest fresh ears from the July-planted sweet corns. The fresh ears of the 20 July-planted sweet corns are able to be harvested by early October. Therefore it will be a good choice for the cropping system based on winter vegetable cash crops such as temperate garlic and onion with medium or late maturity. Among three planting dates 20 July-planted sweet corns had the best field performance in every year considering fresh ear yield, ear size, and stability to grow.

• KOREAN JOURNAL OF CROP SCIENCE
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• v.66 no.2
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• pp.138-145
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• 2021

Perilla contains more than 60% of fatty acids. Linolenic acid is effective in preventing heart disease, improving learning ability, treating allergies, and preventing cancer. This study was carried out to improve the cultivation method to aid the stable production of perilla by developing a suitable inter-cropping system with sesame in the central region as well as to report a suitable planting time. The test results are summarized as follows. As the planting time of perilla in the inter-cropping system with sesame was delayed, the number of clusters and capsules decreased. The perilla yields in this system showed significant differences compared to that with the previous crops (sesame varieties) and planting period. The yield of perilla was significantly lower in the characteristic-Type B variety than in the characteristic-Type A variety and decreased significantly as the planting time was delayed. With regards to the quality characteristics of perilla, such as crude protein, crude fat, etc., there were no differences between previous perilla crops and those inter-cropped with sesame. The perilla composition did not show any difference during the planting period; however, with delay in the planting time, crude protein content increased but crude fat content decreased. Yield of perilla was 38% higher in a two-row (40 x 40 cm) system, compared to a single-row cultivation (110 x 20 cm) of perilla inter-cropped with sesame. These results suggest that the suitable method for inter-cropping perilla with sesame in the central region is to sow the characteristic-Type A variety in early May, and cultivate the perilla in two lines (40 x 40 cm) in mid-June. This was judged to be the best cultivation method in the central region.

• KOREAN JOURNAL OF CROP SCIENCE
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• v.40 no.2
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• pp.260-267
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• 1995

In temperate zone planting rice at different date subjects the Crop to different climatic condition. The present study aimed at comparison of the change in source-sink relationship of the Japonica(J) and that of IndicaxJaponica(I$\times$J) type rice cultivars caused by shift of heading date. Two J- and two I$\times$J-type cultivars were made to head on August 16, August 26, and September 5. Sink capacity was changed by shift of heading date in different mode between the types of cultivars. In both types major determinant of sink capacity was number of effective tillers, and the number of spikelets per panicle was the minor. In J-type earlier planting/heading was beneficial to increased panicle numbers and this was due mainly to a larger diurnal difference in temperature. I$\times$J-type cultivars favored a higher daily mean temperature to increase the sink capacity. The ability of source at heading, in terms of leaf area per panicle, chlorophyll content per spiklet, photosynthetic ability of leaves per unit area at 25$\^{\circ}C$, carbohydrate and N contents of leaves, was not so different among different heading dates in both types. However, the source activity was governed principally by temperature during grain filling. The J-type cultivars headed on Sept. 5 and I$\times$J-type cultivars headed later than August 16 could not have had sufficient source activity in grain filling due to lower temperature.