• Proceedings of the Korean Society of Crop Science Conference
• /
• 2017.06a
• /
• pp.346-346
• /
• 2017

In Northern Laos, maize is cultivated in continuous cropping without fertilizer, fallowing nor any other soil conservation practice. It is expected that this inadequate management in maize cultivation will degrade soil and decrease yield. However, there is limited information about the change of soil condition and yield under continuous maize cultivation. We tried to evaluate the change of soil condition and yield under continuous maize cultivation in Northern Laos. Our study was conducted in farmer's flat and slope fields in Sainyabuli province where maize cultivation had been introduced earlier than the other provinces of Northern Laos. Our study was conducted in 21 fields in 2014, and in 19 fields in 2015. We analyzed grain yield and soil characteristic (total carbon (TC), total nitrogen (TN), available phosphorus (Av-P), exchangeable cation, pH, soil texture) at 3 places in each field. The 3 places were set at different elevation level (lower position, middle position, upper position) in slope fields. Further, the period of continuous maize cultivation and crop management practice were investigated. Then, by evaluating the relation between the period of continuous maize cultivation and yield and the soil characteristics, the effect of maize cultivation was estimated. Crop management practices were similar among the investigated fields. Maize was cultivated in rain season. Grain seed and cob were harvested on September or October, but shoot was left on the fields. No crop was cultivated during dry season. Fertilization and fallowing has never been conducted under continuous maize cultivation. On the other hand, the period of maize cultivation was different among the fields, and ranged from 2 years to 30 years. In the slope fields, as the period of continuous maize cultivation was longer, the contents of TC and TN were lower at all 3 positions, Av-P content was lower at the upper position, exchangeable potassium (Ex-K) content was lower at the middle and the upper positions. The other soil characteristics weren't related with the period of maize cultivation in the slope fields. In contrast, soil characteristics weren't related with the period of maize cultivation in the flat fields. Yield was lower as the period of maize cultivation was longer at the upper position of the slope fields. At middle position of slope fields, yield tended to be low with increase of the period of maize cultivation. In contrast, yield wasn't related with the period of continuous maize cultivation in flat fields. From the results about crop management, it was presumed that the period of maize cultivation was one of the main factors causing the difference of yield and soil characteristics among the fields. Therefore, from the result of yield and soil condition, it was considered that the continuous maize cultivation decreased soil productivity in the slope fields with decline of TC, TN, Av-P, Ex-K and yield at upper position of slope fields, and decline of TC and TN in the other positions in Sainyabuli province.

• Plant Resources
• /
• v.8 no.1
• /
• pp.48-51
• /
• 2005

Optimmum cultivation period was determined for producing seed bulb of Korean native Allium wakegi Araki in vitro in hydroponic culture. The growth gradually increased during cultivation period. In general, plants grown for 5 months produced significantly the highest bulb number and bulb fresh weight per plant. Raising the cultivation period from 1 to 5 months remarkably increased seed bulb yield.

• Journal of Society of Preventive Korean Medicine
• /
• v.1 no.1
• /
• pp.59-75
• /
• 1997

After examining the viewpoints of the mental cultivation of The yellow Emperor's Internal Bible(內徑), from the viewpoints of The yellow Emperor's Internal Bible, I studied the principles and methods of the mental cultivation(精神養生) which the Taoism School, the Confusian School and the past physicians proposed. And I studied the methods of mental cultivation of the child, the woman and the old by the differences of ages and sex. At the subject of health preservation(養生學) on the basis of concept of relevant adaptation of man to nature(天人相應思想), the mental cultivation(精神養生) was regard more important than the body cultivation(肉體養生) and it was considered that the success of health preservation depended on the state of mind. the basic principles of the mental cultivation is achivement of the mental internal keeping(精神內守) through the state of peace and tranquility without avarice and wild fancy(恬憺虛無). The ways of mental cultivation of the Taoism School, the Confusian School and the past physicians were in the category of The yellow Emperor's Internal Bible. 4. In the previous Jin dynasty(先秦時代), the important theoretical bases and practices to mental cultivation were made. In the Han dynasty(漢時代), the physicians attached importance to mental treaments. During the time from Sui dynasty to Tang Dynasty(隋唐時代), the mental cultivation was made perfect theoretically. During the Period from Song dynasty to Yuan Dynasty(宋元時代), Many methods of mental cultivation were newly created. During the Ming and the Qing Dynasties(明淸時代), the theory of health preservation and the methods of mental treaments were embodied. 5. Studying the mental cultivation by the differences of ages, the childhood(小兒期) is the spring of life. So the mental cultivation of this period put importance to the cultivation of Sh ng(養生). And the youth(靑年期) is the summer of life. So the mental cultivation of this period pill importance to the cultivation of Ch'ang(養長). And the middle age(中年期) is the autumn of life. So the mental cultivation of this period put imporance to the cultivation of Shou(養收). And the old age(老年期) is the winter of life. So the mental cultivation of this period put importance to the cultivation of Tsang(養藏). Studying the mental cultivation by the differences of sex, the man must do the mental cultivation through the dynamic nature(性情) of Yang(陽) and the woman must do the mental cultivation through the static nature of Yin(陰).

• Korean Journal of Medicinal Crop Science
• /
• v.19 no.4
• /
• pp.246-250
• /
• 2011

This study was carried out to investigate the characteristics of Rhizome rot incidence of Platycodon grandiflorus by cultivation period and ridge width and furrow depth. The three types of ridge width 0.8, 1.0, and 1.2 m and several levels of furrow depth and 6 levels cultivation period. This experiment was done in farmer's farm and the treatments were also classified in the same spot. In this investigation, ridge width, soil water content, soil hardness, and cultivation period were positively related with Rhizome rot incidence, however, furrow depth was negatively related with that. So this experiment could draw a conclusion : excess water damage and soil hardness could directly or indirectly effect on the Rhizome rot incidence, so cultivation method should be developed such as making underground ditch or cultivation in well draining soil for escaping excess waster damage.

• Korean Journal of Agricultural Science
• /
• v.39 no.4
• /
• pp.459-466
• /
• 2012

The objective of this study is to observe growth pattern of grand rapids(lettuce) according to different dexperimental conditions for minimizing its growth period such as composition of nutrient, irradiation time of light source and cultivation mode. The culture of water spray type using seeds of grand rapids was performed during growth period of total 50 days. Experimental conditions consist of five compositions of nutrient (PW 0.5 mS/cm, PW 1.0 mS/cm, PY 0.5 mS/cm, PY 1.0 mS/cm, PW 2.0 mS/cm) and three irradiation times of light source (12h(on) / 12h(off), 18h(on) / 06h(off), 24h(on) / 00h(off)). Illumination was adjusted to ratio of 7:1:1 of red, blue and white color, respectively. Indoor environmental condition for cultivating grand rapids is as follows: temperature (19-$22^{\circ}C$), relative humidity (60-70%) and carbon dioxide (1,000-1,200 ppm). The data were obtained from five iteration tests. The maximum growth level was observed in the experimental condition of 18 hr(on) / 06 hr(off) and PY 1 mS/cm for 1st week of cultivation period, 24 hr(on) / 00 hr(off) and PY 1mS/cm for 2nd week of cultivation period, and 24 hr(on) / 00hr(off) and PW 1 mS/cm for 3rd week of cultivation period, respectively. On the contrary, the minimum growth level was observed in the experimental condition of 18 hr(on) / 06 hr(off) and PW 0.5 mS/cm for 1st week of cultivation period, 12 hr(on) / 12 hr(off) and PW 0.5 mS/cm for 2nd week of cultivation period, and 12 hr(on) / 12 hr(off) and PY 0.5 mS/cm for 3rd week of cultivation period, respectively. Based on the results obtained from this study, it is concluded that the growth level of grand rapids varied with different irradiation time of light source and composition ratio of nutrient according to cultivation period.

• KOREAN JOURNAL OF CROP SCIENCE
• /
• v.64 no.3
• /
• pp.213-224
• /
• 2019

There is an increasing frequency in the occurrence of abnormal weather phenomena such as sharp increases and decreases in temperature. Under these weather conditions, the heading time of rice changes unexpectedly, which poses problems in agriculture. Therefore, we investigated the effect of temperature on the heading response at different growth stages in rice. During the period from transplanting to heading, the plants were subjected to different temperature treatments, each for a 9-day period, to observe the heading response. For the heading date analysis, "heading date" was defined as the number of days from transplanting to the appearance of the first spikelet. We found that the influence of temperature increased in the order of rooting stage, followed by meiosis, early tillering, spikelet differentiation, and panicle initiation stage in all ecological types and cultivars. In particular, unlike the results reported previously, the effect of temperature on heading during the photo-sensitive period was very small. Meanwhile, the influence of temperature on vegetative growth response at different growth stages was not consistent with heading response. These results can be used as basic data for predicting the variation in heading date owing to temperature variation at each growth stage. In addition, we propose that the concept of day length should be included in determining the influence of temperature on the photo-sensitive period.

• Journal of Mushroom
• /
• v.5 no.3_4
• /
• pp.91-97
• /
• 2007

Shiitake mushroom (Lentinula edodes) is usually cultivated on the oak log. Log cultivation of this mushroom is getting difficult to get oak logs and has a weak point of its long cultivation period. Recently sawdust cultivation is getting increase. It is important to make mycelia browning on the substrate surface. This browned surface in sawdust cultivation plays an important role like as artificial bark of the oak log, which protects the other pests and suppresses water evaporation in the substrate. The period for mycelia browning is so long that the sawdust cultivation of Shiitake mushroom can not spread well into the mushroom farms. The development of methods for the rapid mycelia browning is quite required. In this article we would like to discuss about the enzymatic activities related mycelia browning and search the methods of cultivation period reduction.

• Journal of Environmental Science International
• /
• v.30 no.12
• /
• pp.1015-1025
• /
• 2021

Our research work aimed to evaluate cover crop effects of winter rye on soil characteristics, soil conservation, and yield productivities on potato fields with 15% slope during a fallowed period. There were two controls of bared field without any cultivation and conventional potato cultivation without winter rye. Potato cultivation increased soil pH, organic matter, available phosphate, and exchangeable cation regardless of cover crop cultivation. Sub-soil, particularly, all components of soil chemical properties showed higher value in winter rye cultivation than conventional cultivation. Higher soil density was observed on cover crop cultivation than conventional cultivation resulting from root residues of the cover crop both topsoil and subsoil. Cover crop residues positively affected plant growth and reduced the amount of soil erosion by holding the soil. Although severe soil erosion was seen in conventional cultivation, winter rye cultivation declined soil erosion by 47% during the fallow period on potato slope fields. Distinct soil bacterial communities were detected among treatments and some OTU(Operational Taxonomic Unit)s showed significantly higher abundance in winter rye treatment. Total yield and commercial rate demonstrated no significant differences while higher tuber phosphate, K⁺, and Mg²⁺ contents were observed in winter rye cultivation.

• Journal of the Korean Society of Tobacco Science
• /
• v.2 no.2
• /
• pp.44-50
• /
• 1980

The growth of flue-cured tobacco was analyzed with the mathematical treatment. The results are summarized as followings: 1. The growth curve was fitted to the quadratic polynomial equation in improved-mulching cultivation, blot to the Gompertz equation in the other cultivations. 2. The initial point of the maximum growth phase for dry weight was about 50 days after transplanting in improved-mulching cultivation, but about 40 days in the other cultivations, and the maximum growth period was for 25 days in all cultivations. 3. The growth rate of the maximum growth period in dry weight decreased in the order of improved-mulching cultivation, mulching cultivation, and non-mulching cultivation. 4. A relative growth amount in the maximum growth period was higher in later sowing. 5. The length of maximum growth was 5 days shorter in leaf area than in dry weight. The maximum growth phase was 7 days earlier in leaf area than in dry weight.

• The Korean Journal of Mycology
• /
• v.49 no.4
• /
• pp.525-530
• /
• 2021

The cultivation in sawdust media, mushroom productivity, and fruiting body characteristics of Lentinula edodes strains NIFoS 2778 and NIFoS 3363 were compared according to the inoculation conditions. The cultivation period was 5% shorter when liquid spawn was used. Fruiting bodies were induced after 113 days of incubation on media inoculated with liquid spawn, and the cultivation period was 119 days on media inoculated with solid spawn. Mushroom productivity of NIFoS 2778 was the highest (661.4 g) when 36 mL of liquid spawn was used. For NIFoS 3363, mushroom production was higher under liquid inoculation conditions when the same amount of liquid and solid spawns were used. The mushroom characteristics of the two strains were not significantly different, except for gill width and stipe diameter.