• Preventive Nutrition and Food Science
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• 제17권4호
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• pp.280-285
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• 2012

Six polyphenolic compounds, such as chlorogenic acid (CA), rutin (RT), isoquercitrin (IQT), quercetin-3-O-(6-O-malonyl)-${\beta}$-D-glucoside (QMG), astragalin (AG), kaempferol-3-O-(6-O-malonyl)-${\beta}$-D-glucoside (KMG), were isolated from mulberry leaves by a series of isolation procedures, such as Diaion HP-20, silica-gel, Sephadex LH-20, and ODS-A column chromatographies. The chemical structures of the phenolic compounds were identified by UV and NMR spectral analyses. Levels of polyphenols in mulberry leaves from six different mulberry cultivars ranged from 1,042.16 to 1,871.97 mg% per dry weight; Guksang cultivar showed the highest levels of polyphenols, whereas Gaeryangdaehwa contained the least polyphenol contents. Generally, levels of polyphenols in mulberry leaves decreased with increasing harvest time, except for Yoolmok, but increased with heat processing time, except QMG and KMG. These results suggest that the heat processed mulberry leaves of Guksang cultivar harvested in early May can be potentially useful sources for production of high quality mulberry leaf teas.

• 한국잠사곤충학회지
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• 제31권1호
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• pp.12-19
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• 1989

추기 된서리로 인한 자연낙엽에 관계없이 상묘를 굴취할 수 있도록 하기 위하여 1985년부터 2년간 전국 각도 9개 지역에서 9월 30일부터 11월 20일까지 10일 간격으로 6회에 걸쳐 굴취하여 묘질을 분석한 결과 다음과 같았다. 1. 묘목의 굵기는 10월 30일까지 다소의 증가를 보였다. 2. 조기굴취는 그루당 새순의 수와 길이를 떨어뜨렸으며, 10월 30일 굴취구에서 생육이 가장 양호하였다. 3. 10월 20일 이후는 자연낙엽에 관계없이 굴취하여도 활착율과 생육에 영향을 주지 않았다. 4. 굴취시기를 늦을수록 체내에 전실소와 P함량이 증가되는 반면 K는 감소하였으며 Ca는 일정하지 않았다. 5. 전실소, P, Ca 등은 뿌리껍질에서 보다 줄기껍질에 함량이 높았으며 K는 일정하지 않았다.

• 한국자원식물학회지
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• 제21권2호
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• pp.128-133
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• 2008

구절초와 남구절초의 수확 시기에 따른 항산화 효과를 비교하기 위하여 본 연구를 실시하였다. 구절초와 남구절초를 생육초기(5월 9일), 중기(7월 17일) 그리고 생육 후기(9월 3일)에 각각 수확한 후 80% 에탄올로 추출하여 radical 소거활성 및 항산화 물질 함량을 측정하였다. 수확 시기가 늦어질수록 식물체의 수분 함량과 추출 수율이 낮아졌다. DPPH 및 ABTS radical 소거능은 이른 시기에 수확한 시료일수록 활성이 높은 경향을 보였다. 구절초의 DPPH radical 소거능은 생육 초기에 수확한 시료가 $0.128mg\;{\cdot}\;mL^{-1}$의 $RC_{50}$값을 나타내 $BHT(RC_{50}=0.121mg\;{\cdot}\;mL^{-1})$와 비슷한 소거능을 보였고, 생육 초기에 수확한 남구절초와 구절초는 천연 항산화제인 ascorbic acid보다도 높은 ABTS radical 소거활성을 나타냈다. 그러나 $Fe^{2+}$ chelating 효과의 경우, 구절초를 생육 후기에 수확하는 것이 초기나 중기에 수확하는 것 보다 높았으며, EDTA에 비해서도 훨씬 낮았다. 두 종 모두 수확 시기가 빠를수록 총 폴리페놀 및 플라보노이드의 함량이 높은 경향을 보였으며, 생육 초기에 수확한 구절초와 남구절초의 총 폴리페놀 함량은 각각 79.93 및 $75.10mg\;{\cdot}\;g^{-1}$로 총 플라보노이드 함량(57.84, $54.91mg\;{\cdot}\;g^{-1}$)에 비해 높았다.

• 한국초지조사료학회지
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• 제11권1호
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• pp.17-21
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• 1991

A field experiment was carried out to determine the effects of nitrogen(N) fertilization levels(0, 30, 60, 90 and 120 kg/ha) in early spring on the growth, dry matter(DM) yield, seasonal distribution of production and nutritive value of grasses. Additional N after the first, second and third harvest were applied as 60, 60 and 30 kg/ha, equally in 1989. Grass growth and DM yield were significantly increased(p$NO_3$-N concentration was not affected by N level of early spring. It is suggested that, therefore, N application in early spring is essential, and 60 to 90 kg/ha of N application may be desirable in early spring.

• 한국초지조사료학회지
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• 제36권4호
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• pp.376-380
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• 2016

This experiment was carried out to investigate the effect of harvesting time of Italian ryegrass (Lolium multiflorum Lam; IRG) in spring on dry matter (DM) yield. IRG cultivars 'Kowinearly' and 'Greenfarm' were seeded at 50 kg/ha and grown on rice paddy fields. There was no difference in growth characteristics between both varieties before winter. However, cold tolerance of Kowinearly was higher than that of Greenfarm, as demonstrated by post-wintering growth characteristics. The heading date of both varieties was affected by the spring weather. The IRG was harvested three times at 5-day intervals beginning from 9 May. The DM yield of Greenfarm was 6,306; 7,335; and 8,109 kg/ha, and that of Kowinearly was 7,498; 9,196; and 10,449 kg/ha at the three consecutive harvests. The delay of the harvesting time for 5 and 10 days increased the DM yield of Greenfarm by 16% and 29% and that of Kowinearly by 23% and 39%, respectively, compared to the yield at first harvest (p < 0.05). Therefore, IRG harvest later than early to mid-May is expected to increase productivity. The feed values of Greenfarm were: 12.2% of crude protein (CP), 34.5% of acid detergent fiber (ADF), 57.7% of neutral detergent fiber (NDF), 61.6% of total digestible nutrients (TDN), and 72.3% of in vitro DM digestibility (IVDMD). For Kowinearly, these values were 16.4% of CP, 30.4% of ADF, 52.7% of NDF, 64.9% of TDN and 79.0% of IVDMD.

• 농업과학연구
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• 제45권3호
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• pp.355-363
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• 2018

This study was conducted to investigate suitable rice cultivars for various rice based cropping systems in a paddy field in the Yeongnam plain area. Thirteen rice cultivars (5 early, 3 medium and 5 mid-late maturing cultivars) and three transplanting dates (June 5, June 25 and July 5) were evaluated in this study. The mid-late and early maturing cultivars for the July 5 and June 25 transplanting headed before August 30 which is the safe heading date in the Yeongnam plain area, ranging from Aug. 26 - 28 and Aug. 18 - 23, respectively. The safe harvest time of rice for double and triple cropping systems should be before the middle of October for the cultivation of the succeeding winter crops. The rice yield was the highest for the June 5 transplanting regardless of the rice cultivars, and it gradually decreased as the transplanting date was delayed from June 5 to July 5 due to a decrease in the spikelet numbers per panicle number and in the ripened grain rate. In contrast, the other yield parameters that include the panicle number per $m^2$, the 1,000-brown rice weight, and the ripened grain ratio were not significantly affected. The result indicates that based on the milled rice, heading time and harvest time, a medium maturing cultivar (Haiami and Samdeog) would be applicable to a winter barley/wheat, garlic/onion-summer rice double cropping, while a mid-late cultivar (Saeilmi, Saenuri and Hyunpoom) would be suitable for a spring potato/waxy corn-summer rice double cropping in the Yeongnam plain area. On the other hand, an early maturing cultivar (Unkwang, Jokwang and Haedamssal) would be preferable for a triple cropping because of the short growth period of rice.

• 한국초지조사료학회지
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• 제32권4호
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• pp.353-360
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• 2012

This study was conducted to evaluate the nutritive value and the quality of ensiled kenaf after fermentation with three cultivars at three different times of harvesting. Experimental plot were allocated with three harvest date (Early;8/3, medium;8/15 and late;8/28) and three cultivars (Tainung-a, Everglade, Whitten). The DM (dry matter) yield increased with maturity in all three cultivars, especially in Whitten which showed the highest yield at each harvest time. The DM content in Whitten at late harvesting time was higher than other treatments (231 g $kg^{-1}$ DM). The CP (crude protein) contents of the kenaf silage of all three cultivars ranged from 151 to 164 g $kg^{-1}$. Highest content of NDF (neutral detergent fiber) was observed in Everglade at medium harvesting date, but the ADF (acid detergent fiber) content was highest in Everglade at early harvesting date (p<0.05). All treatments produced a pH less than 4.0, which is sufficient for stable storage. The pH of Tainung-a was higher than other cultivars at all harvesting times (p<0.05). Whitten showed the higher content of lactic acid (25.8 g $kg^{-1}$ DM) showed at early harvesting date than other cultivars (p<0.05), while the acetic acid content (21.1 g $kg^{-1}$ DM) was higher in Tainung-a at medium harvesting date (p<0.05). No significant difference was observed in ammonia-Nand butyric acid concentrations among all treatments. These results indicate that a kenaf silage could be used as fodder for ruminants. Especially, the Whitten harvested at late growing stage showed promise as a forage silage crop under Koran environments.

• 한국작물학회지
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• 제61권2호
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• pp.104-112
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• 2016

A double-cropping system with soybean (Glycine max) following the cultivation of potato, garlic, and onion is widely adopted in the southern region of Korea. For this system, marginal dates for planting must be determined for profitable soybean yields, because the decision to plant soybean as a second crop is occasionally delayed by harvest of the first crop and weather conditions. In order to investigate the effect of planting date on soybean yield, three cultivars (early and late maturity) were planted on seven different dates from May 1 to July 30 in both paddy and upland fields across 2012 and 2013. Soybean yields were significantly different among the planting dates and the cultivars; however, the interaction between cultivar and planting date was not significant. Based on linear regression, the maximum yield of soybean was reached with a June 10 planting date, with a sharp decline in yield for crops planted after this date. The results of this study were consistent with those of a previous one that recommends early and mid-June as the optimum planting period. Regardless of soybean ecotype, a reduction in yield of greater than 20% occurred when soybean was planted after mid-July. Frost during soybean growth can reduce yields, and the late maturity cultivars planted on July 30 were damaged by frost before completing maturation and harvest; however, early maturity cultivars were safely harvested. For sufficient time to develop and reach profitable yields, the planting of soybean before mid-July is recommended.

• 한국작물학회지
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• 제49권5호
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• pp.373-380
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• 2004

The production of sweet (su) and super sweet corns (sh2) has been economically feasible in Korea in recent years. Major factors limiting super sweet corn production are low germination and low seedling vigor. Since seed quality is closely related to seed maturity, the optimum harvest time for the seed production of sweet and super sweet corns was studied and the quality of seeds with varying maturities was investigated in 2001 and 2002 cropping seasons. The parents of the sweet corn seeds were Hybrid Early Sunglow and 'Golden Cross Bantam 70' and those of super sweet corn were Xtrasweet 82 and 'For­tune'. Seeds were harvested at 21, 28, 35, 42, 49, and 56 days after silking (DAS). As the seeds developed, seed weight of sweet corn increased and the seed moisture content decreased faster than that of super sweet corn. Germination rates of sweet corn seeds harvested 21 and 28 DAS at $25^{\circ}C$ and emergence rates in the cold soil test were significantly lower than those of seeds harvested after 42 DAS in both years. Although the germination rates of super sweet corn seeds with varying maturities showed similar patterns as sweet corn seeds at $25^{\circ}C$, the emergence rate of super sweet corn seeds in cold soil test continuously increased with seed maturity. This suggests that seed quality of super sweet corn should be tested in a cold soil test to estimate field emergence. As the seeds developed, leakage of total sugars and electrolytes from the both sweet and super sweet corn seeds decreased up to 42 or 49 DAS. The $\alpha-amylase$ activities of both sweet and super sweet corn seeds increased with seed maturity from 21 to 35 or 49 DAS depending on genotype and year. The optimum harvest time for the seed production of sweet corn was 42 DAS and 49 DAS for super sweet corn considering emergence rate and plumule dry weight in the cold soil test, leakage of sugars and electrolytes from the seeds, and $\alpha-amylase$ activity.

• 한국약용작물학회지
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• 제28권2호
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• pp.136-141
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• 2020

Background: The leaves of the goji berry (Lycium chinense Mill.) are used as raw materials in processing and by replace fruits to some extent. The reason is that the leaves are cheaper, however, betaine content is higher than in the fruits. These experiments were conducted to determine the planting density and cutting height for producing a large number of leaves. Methods and Results: The cultivar 'Myeongan' with many branches was used. When the shoot height reached 50 cm - 70 cm, harvesting was possible four times a year. The time to next harvest was approximately 38 days after regeneration of new shoots. Leaf quantity was in the order of 1st > 2nd > 4th > 3rd harvest. Insect damage occurred during the third harvest in late July and early August, therefore, eco-friendly control was necessary. The total yield was higher at the planting density 60 cm × 30 cm than that of 60 cm × 20 cm or 60 cm × 40 cm. The yield at cutting for shoot height of 60 cm was increased by 6.3 percent compared to that of 50 cm, At the cutting height of 70 cm, harvest was difficult owing to hardening of stems and thorns. Betaine content, an indicator component of goji berry, was not significantly different according to planting densities and cutting height. Conclusions: The ideal cutting period to produce leaves of goji berry for processing is when the shoots grow to approximately 60 cm, and the leaves can be harvested 4 times a year. The dried-leaf yield was highest at the planting density of 60 cm × 30 cm.