• KOREAN JOURNAL OF CROP SCIENCE
• /
• v.57 no.4
• /
• pp.418-423
• /
• 2012

Field experiments were carried out to improve the cultural practice of potato by analysing its tuberization patterns. Tuberization patterns affected by different altitudes was analyzed at two potato cultivation regions, Jinbu (600 m) and Daegwallyung (800 m) using two potato cultivars, 'Superior' and 'Atlantic'. To analyse tuberization patterns affected by different planting time, seed potatoes were planted at every 10 days from April 19 to May 19 in Daegwallyung. Total dry weight was greater in plant grown at the altitude of 800 m than 600 m during the entire growth period and the highest increase was observed at the early growth period, July 6, comparing to other growth period. The total dry weight was the greatest at 110~112 days after planting (DAP) at the altitude of 800 m and 108~111 DAP at 600 m. There was no significant differences between altitudes and between cultivars. Tuber dry weight per plant at the altitude of 600 m was lower than 800 m on July 6 (58 DAP), but it increased rapidly from July 21 (73 DAP). At both altitudes, the increase of tuber dry weight per plant from July 6 to August 8 was higher than the other growth period. The time of growth period at which tuber dry weight per plant was the highest was similar at both altitudes that was 118~125 DAP at the altitude 800 m and 118~124 DAP at the altitude 600 m. Dry weight per tuber at the altitude 800m was higher than 600 m due to the number of tubers per plant. A higher increase of crop growth rate (CGR) was shown at the altitude 600 m on July 6 (58 DAP), comparing to at 800 m. The highest tuber dry weight per plant of each cultivar was shown when the planting time was April 29 for 'Superior' and was April 19 for 'Atlantic'. Both the tuber dry weight of plant and the total dry weight were lower at a later planting time. Dry weight per tuber increased quickly during the period between June 30 to August 8. Tuberization period was shortened as the planting time was delayed.

• KOREAN JOURNAL OF CROP SCIENCE
• /
• v.66 no.4
• /
• pp.419-427
• /
• 2021

In South Korea, direct seeding of rapeseed (Brassica napus L.) is difficult during spring cultivation in early March because of the low yield production associated with late flowering and poor seed quality. To compare the period of direct sowing, the present study investigated the growth characteristics of rapeseed according to planting dates. Specifically, 35 day-old seedlings were transplanted or directly sown on four different dates (late February, early March, late March, and early April) in 2020 and 2021. As the planting date was delayed, the days to flowering of rapeseed decreased. Similarly, the plant height, seed set percentage, and seed yield of rapeseed were reduced upon delay in planting. The seed yield of rapeseed through direct seeding in late February was the highest, 2.76 ton·ha^-1. On all seeding dates, except for late February, the transplanted rapeseed produced a higher yields than the directly seeded rapeseed. The crude oil and oleic acid content, which is related to the quality of rapeseed, decreased with the delay in planting dates, and this decrease was greater, with the direct seeding of rapeseed depending on the sowing time. In the correlation analysis, the planting date was significantly and negatively correlated with the yield, crude oil content, and oleic acid content of the transplanted rapeseed, while the sowing date was negatively correlated with the plant height, silique size, yield, and seed quality of the directly seeded rapeseed. Finally, the effect of planting date on rapeseed growth was stronger in direct seeding than in transplanting. Therefore, during spring cultivation after late February to early March, transplanting, rather than direct seeding, in more advantageous in terms of seed quality and yield.

• Journal of The Korean Society of Grassland and Forage Science
• /
• v.12 no.3
• /
• pp.193-200
• /
• 1992

This study was carried out to determine the optimum fertilizer level of phosphate for maximum yield of soiling cowpea(Vigna sinensis Endlicher) in Cheju. The results obtained are summarized as follows:1. Plant length, fresh yield, stem and leaf weight per plant, node number of main stem, primary branch number per plant, pod number per plant and pod weight per plant increased with increasing of phosphate level regardless of growth stage.2. Plant length and node number of main stem did not increase after August 25, 40 days after planting. Leaf weight and fresh yield were greatest on August 25, and then reduced. 3. Stem weight the number of leaves and pods and pod weight per plant increased until September 13, 80 days after planting. 4. Increased level of phosphate delayed leaf weight decrease after August 25. 5. Root length and root weight per plant increased with increasing level of phosphate regardless of growth stage, and they did not increase after Augest 25. 6. Nodule number and nodule weight per plant also increased as phosphate rate increased regardlessof growth stage. Nodule number and nodule weight were greatest on August 5, and then rapidly decreased.

• KOREAN JOURNAL OF CROP SCIENCE
• /
• v.25 no.2
• /
• pp.15-22
• /
• 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 Agricultural and Forest Meteorology
• /
• v.18 no.2
• /
• pp.74-87
• /
• 2016

Potato phenology, growth, and yield are projected to be highly affected by global warming in the future. The objective of this study was to examine the responses of potato growth and yield to environmental elements like temperature, solar radiation, and daylength. Planting date experiments under open field condition were conducted using three cultivars differing in maturity group (Irish Cobbler and Superior as early; Atlantic as mid-late maturing) at eight different planting dates. In addition, elevated temperature experiment was conducted in four plastic houses controlled to target temperatures of ambient temperature (AT), $AT+1.5^{\circ}C$, $AT+3^{\circ}C$, and $AT+5^{\circ}C$ using cv. Superior. Tuber initiation onset was found to be hastened curve-linearly with increasing temperature, showing optimum temperature around $22-24^{\circ}C$, while delayed by longer photoperiod and lower solar radiation in Superior and Atlantic. In the planting date experiments where the average temperature is near optimal and solar radiation, rainfall, pest, and disease are not limiting factor for tuber yield, the most important determinant was growth duration, which is limited by the beginning of rainy season in summer and frost in the late fall. Yield tended to increase along with delayed tuber initiation. Within the optimum temperature range ($17^{\circ}-22^{\circ}C$), larger diurnal range of temperature increased the tuber yield. In an elevated temperature treatment of $AT+5.0^{\circ}C$, plants failed to form tubers as affected by high temperature, low irradiance, and long daylength. Tuber number at early growth stage was reduced by higher temperature, resulting in the decrease of assimilates allocated to tuber and the reduction of average tuber weight. Stem growth was enhanced by elevated temperature at the expense of tuber growth. Consequently, tuber yield decreased with elevated temperature above ambient and drop to almost nil at $AT+5.0^{\circ}C$.

• KOREAN JOURNAL OF CROP SCIENCE
• /
• v.39 no.5
• /
• pp.512-518
• /
• 1994

One of most laborious work in rice farming is transplanting of rice seedling which has been required preparation of nursury bed and care of seedling during one month period. In this research, direct seeding in dry paddy(DS) was practiced to compare with traditional tansplanting(TP) in Suwon and Milyang. Growth stages in DS were delayed as its planting time was about 36 days later than TP. Heading stage of DS at Suwon was delayed about 15 days as compared to transplanting culture. Rice yield in DS was decreased 8.2%(Suwon) and 0.11%(Milyang), repectively. Working-hour saving in DS was about 34.0%(Suwon) and 54.0%(Milyang). Production cost of DS was decreased 19%(Suwon) and 29% (Milyang), repectively. Amount of rice production per a unit working-hour in DS could incresed 37%(Suwon) and 113%(Milyang) compared to that of TP, respectively. Therefore, DS was decreased little in rice yield, but it could save working hour and production cost, significantly. Warm region like Milyang had more advantage in DS than Suwon. But, DS needs varietal selection for better emergence in low temperature, and more research in weed control and water management.

• KOREAN JOURNAL OF CROP SCIENCE
• /
• v.41 no.1
• /
• pp.115-122
• /
• 1996

One of the most laborious work in rice farming is transplanting of rice seedling which has been required preparation of nursery bed and care of seedling during one month period. In this research, direct seeding in dry paddy(DS) and direct seeding in wet paddy(WS) were practiced to compare with traditional transplanting(TP) in Suwon. Growth stages in direct seeding were delayed as its planting time was about 21 days later than those of TP. Heading stage of direct seeding at Suwon was delayed about 9 days as compared to transplanting culture. Rice yield was not different between the seeding practises. Working-hour saving was about 17％(DS) and 28％(WS). Production cost of direct seeding was decreased 20％(DS) and 32％(WS), respectively. Amount of rice production per a unit working-hour in direct seeding could increase 14％(DS) and 39％(WS) compared to that of TP, respectively. Therefore, direct seeding could save significantly working hour and production cost without reducing rice yield. WS was more effective than DS in saving labor and production cost. Direct seeding was not efficient method in input of farming energy and agricultural chemicals.

• Korean Journal of Plant Resources
• /
• v.29 no.4
• /
• pp.511-518
• /
• 2016

The subject of this experiment is to supply basic data to inhibit non-productive tillers which are uneconomical for mechanical harvesting and to evaluate optimum planting density and sowing date in central district. Total number of tillers and effective first and second of tillers according to different planting density was higher in 80 ㎝ ridge than 60 ㎝ ridge in proso millet. The wider between plant distance on the ridge, the more increased total number of tillers and effective first and second of tillers. The highest effective tillers (91.7 %) in the first tillers was obtained from the second sowing date (23 May) among different sowing date and next is in the order of 3^rd(13 June, 89.8%) > 1^st(2 May, 85.6%) > 4^th(4 July, 85.2%). The percentage of effective tillers in the second tillers was decreased in the order of 2 May (53.7%), 23 May (40.7%), 13 June (22.2%), 4 July (0%) as the sowing date was delayed. There was no significant difference in days to heading and days to ripening according to different planting density. Although culm length was increased as planting density was increased, whereas number of tillers, stem diameter, ear length, grains per ear and 1000 grain weight was decreased. In the growth and yield characteristics of proso millet according to different sowing date, days to heading and days to ripening, culm length, stem diameter, ear length, grains per ear and yield per 10a were decreased. After the sowing date of 13 June, the reduction of growth and yield characteristics were higher because of excess-moisture injury.

• Journal of Bio-Environment Control
• /
• v.19 no.1
• /
• pp.25-30
• /
• 2010

This experiment was carried out to investigate the effect of planting times on the growth and yield of artichoke (Cynara scolymus L.) in non-heated greenhouse in Jeju Island ($33^{\circ}28.110N,\;126^{\circ}31.076E$), Korea. Five transplanting dates (from Feb. 25 to Apr. 30) of the first half of the year and six transplanting dates (from July 30 to Dec. 15) of the second half of the year were compared. In the spring cycle, most of the flower buds emerged from May to June, and the emergence was slightly earlier in 'Imperial Star' than in 'Green Globe'. The earliest harvest on June 16 was 'Imperial Star' which was planted on Feb. 25. The highest yield of 856 kg/10a was observed in 'Imperial Star' which was planted on Feb. 25. Transplanting of the first half of the year, it was impossible to harvest in the same year when the planting was done after April 15 since the flower buds were not emerged. The flower buds emerged from late Feb. to middle April of the following year in the all planting times of the second half of the year. It was possible to harvest the first time in early April. The highest yield was 2,127 kg/10a in 'Green Globe' which was planted on July 30, and the yields decreased as the planting times were delayed. In the comparisons of planting times of artichoke, it would be recommendable to plant artichoke on Feb. 25 for the same year harvest and in July 30~Oct. 15 for the following year harvest in Jeju Island non-heated greenhouse cultivation.

• KOREAN JOURNAL OF CROP SCIENCE
• /
• v.32 no.3
• /
• pp.249-255
• /
• 1987

To find out the optimum planting date of silage corn in the rice black-streaked dwarf virus (RBSDV) pre-valent area, a resistant hybrid of Jinjuok and a susceptible hybrid of Suweon 19 were planted at the 8 planting dates from April 1 to June 10 at the la-day intervals. Considering escape of RBSDV and silage yield, the optimum planting date seems to be during the April in both hybrids. At the April plantings silage yield of two hybrids ranged from 17 to 23 tons/ha on the dry matter base due to a lower infection rate and higher tolerance to RBSDV and there was no difference in silage yield between two hybrids. At the May plantings yield of ear, stover, and silage, culm length, and digestible dry matter decreased significantly as planting date delayed due to an increase in RBSDV infection rate in both hybrids although performance of a resistant hybrid of Jinjuok was better than a susceptible hybrid of Suweon 19. At the June 10 planting RBSDV infection rate was low and performance of corn was better than that at the May plantings but poorer than that at the April plantings. The peak of small brown planthopper population occurred in late March or early April, middle June, middle July, and early September although it fluctuated a little yearly. Very low small brown planthopper population during the May may attribute to a lower RBSDV infection and high silage yields at the April plantings because the plants grow enough to be tolerant when infected by RBSDV in middle June. However, at the May plantings plants are too young to be tolerant when infected by RBSDV in middle June.