• Journal of The Korean Society of Grassland and Forage Science
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• v.32 no.3
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• pp.229-236
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• 2012

This experiment was conducted to evaluate agronomic characteristics and forage productivity of italian ryegrass cultivars at Seongju in the Kyeongbuk from 2010 to 2012. The experiment was arranged in randomized complete block design with three replications. Italian ryegrass cultivars were seeded on Oct. 12 in 2010 and Oct. 3 in 2011. The early-medium maturing cultivars were harvested on 29 Apr. and the medium late ones were harvested on 4 May in 2011. In 2012, the early-medium cultivars were harvested on 28 Apr. and medium late ones were harvested on 12 May. DM (dry matter) yield of the early-medium maturing cultivars 'Yeonbong3', 'Seongnong', 'Winter Hawk', 'Pride' and 'Kowinnearly' was 9,850, 9,778, 9,486, 9,363 and 9,267 kg/ha and DM yield of those were significantly higher (p<0.05) than other seven cultivars or ones. DM yield of the medium-late maturing cultivars 'Tetragold', 'Hwasan 101', 'Jumbo', 'Sungrazer', 'Master', 'SelectIV' and 'KB Royal' was 9,542, 9,492, 9,103, 8,981, 8,903, 8,870 and 8,681 kg/ha and DM yield of those were higher (p<0.05) than other three. Cold tolerance for 'Hwasan 101' was higher than others, in medium-late maturing cultivars. According to the results obtained from this study, it is suggested that early-medium maturing cultivars would be recommendable for DM production.

• Asian-Australasian Journal of Animal Sciences
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• v.11 no.5
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• pp.580-585
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• 1998

The study was conducted to determine if variation in protein yield can be explained by expressions of early lactation somatic cell score (SCS) and if prediction can be improved by including SCS among the predictors. A data set was prepared (n = 663,438) from Wisconsin Dairy Improvement Association (USA) records for protein yield with sample days near 20. Stepwise regression was used requiring F statistic (p < .01) for any variable to stay in the model. Separate analyses were run for 12 combinations of four seasons and first three parities. Selection of SCS variables was not consistent across seasons or lactations. Coefficients of detennination ($R^2$) ranged from 51 to 61% with higher values for earlier lactations. Including any expression of SCS in the prediction equations improved $R^2$ by < 1 %. SCS was associated with milk yield on the sample day, but the association was not strong enough to improve the prediction of future yield when other expressions of milk yield were in the model.

• Proceedings of the Korean Society of Crop Science Conference
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• 2017.06a
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• pp.353-353
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• 2017

Rice yield of South Korea in 2015 was the highest of the last 30 years. It is important issue to establish food policy whether the historically highest yield in 2015 can be continued or just one-off event. Therefore, it is necessary to understand whether such a high yield as 2015 will be reoccurred. The aim of this study was to find out what climatic factor affect rice yield and how often these climatic factor could occur. For this study, the yield monitoring data from National Institute of Crop Science, Rural Development Administration and the meteorological data provided by Korea Meteorological Administration are used to identify the weather conditions could cause high yield, and how often these conditions occurred in the past. Our results indicated that such as high yield as 2015 could occur only when the mean sunshine hours of July and the mean sunshine hours from the end of August to early September was more than 5.1 hours and 6 hours, respectively. Mean sunshine hour of July may be related to grain number. The mean sunshine hour from the end of August to early September was presumed to relate to grain filling ratio. The relationship between monthly mean temperature and yield or yield component was not clear in this study. In this study, any cycle of high weather condition was not found. Therefore, the probability of high yield weather condition was expressed by frequency. The frequency of the sunshine hour, could make high yield, were 8/35 (23%) over the past 35 years. And the frequency of two years consecutive sunshine hour condition, which could cause high yield, was 1/35 (2.9%). The frequency of recurrence of sunshine hour making high yield within the next 5 years or 10 years after high yield weather condition were 4/35 (11.4%). After all, the high yield as much as yield of 2015 could not be one-off event. But it was not also consecutive event.

• KOREAN JOURNAL OF CROP SCIENCE
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• v.32 no.4
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• pp.425-430
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• 1987

The present experiment was carried out to investigate the effects of direct sowing time and transplanting culture of Sculellaria baicalensis GEORGE on the grows, the yield and it's components. The results obtained are summarized as fallows; The number of days from seeding to emergence was recognized lineary negative correlation between seeding dates and transplanting dates. Plant height was longest on Apr. 15 Seeding and Apr. 1 transplanting, and was short in the early seeding and transplanting, and the late seeding and transplanting. Stem diameter was thickest on Apr. 15 seeding and Apr. 1 transplanting, and was thin in the early, and the late seeding and trasplanting. Length and dry weight of root were increased on Apr. 15 seeding. In the transplanting date, Length and dry weight of root were increased on Apr.1. Yield of dry root was highest in Apr. 15 seeding date. In the transplanting culture, yield of dry root was highest in Apr.1.

• Journal of the Korean Society of Tobacco Science
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• v.11 no.1
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• pp.27-39
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• 1989

This study was conducted to determine the time and methods of predicting tobacco yield. by analysis of climatic factors in the period of tobacco season during 8 years from 1979 to 1986 at the Daegu district, south eastern part of Korean peninsular. The results obtained are summarised as follows: 1. Climatic factors of each month which have influence on tobacco yield were the amount of rainfall in May and sunshine hours in July. Among climatic factors at tobacco growth stages, the precipitation yield. But these meteorological factors had different effect on variety. 2. Between tobacco yields and climatic factors by even values of each month, tobacco yield was estimated by equations, flue cured tobacco :Y=190.6-5.230X1+ 0.474$\times$2 + 0.142X3(Xl : Minimum temperature of April, X2: Precipitation during May, X3:Sunshine duration on July), air cured tobacco : Y= 195.3-0.447Xl + 0.363$\times$2 + 0.l12$\times$3(Xl :Maximum temperature of May, X2:Precipitation during May. X3: Sunshine duration on July). While between tobacco yield and climatic factors at different growth stage, predicting equation of yield could be derived, flue cured tobacco : Y=205.8+0.510Xl +0.289$\times$2 + 0.305$\times$3 (Xl :Average temperature during the early growth stage, X2 :Precipitation during the early and maximum growth stage, X3 : Sunshine hours during the leaf and tips maturing stage), air cured tobacco Y=194.T-0.498Xl 10.615$\times$2+0.121$\times$3(Xl ;Maximum temperature during the transplanting time, X2 : Precipitation during the maximum growth stage, X3 : Sunshine hours during the leaf and tips maturing stage).

• Journal of The Korean Society of Grassland and Forage Science
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• v.21 no.4
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• pp.217-224
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• 2001

In order to identify the growth characterization, the yield and chemical composition of Jeju barnyard grass (Echinochloa crusgalli var. fiurnentacea(Roxb) Wight) based on seeding date in Jeju region, seeding carried out the 10-day intervals from March 27 to September 30 in 2000, respectively. Plant height was 143.2 cm, showing the highest on seeding date, April 6 among that of any other seeding date. On the other hand, those of early and late seeding gradually decrease. Plant height was 119.2 an in May 16 seeding. The results of stem diameter, number of withering leaves, number of leaves and fresh weight per plant were similar to those of the plant heights. The yield of fresh, dry matter forage, crude protein and TDN found the highest on April 6 seeding, 63.5 MT/ha, 13.9 MTha, 1.1 MT/ha, and 7.6 MT/ha, respectively. In early and late seeding, the yield was gradually decreased. In seeding May 16, the yield found .38.2 MTIha in fresh forage, 6.2 MTha in dry matter forage, 0.7 MT/ha in crude protein and 3.7 MTha in TDN, respectively. According to delaying the seeding date, March 27 to May 16, the contents of crude protein (from 7.9 to 10.8%), ether extract (from 4.6 to 6.0%), nitrogen free extract (from 45.1 to 46.5%), and TDN (from 54.2 to 60.8%) were gradually increased, respectively. On the other hand, those of crude fiber (from 28.9 to 25.6%) and crud ash (from 13.5 to 11.2%) were decreased. These results showed that April 6 was the optimum seeding date with the sole object of feed production of Jeju barnyard grass under the environmental condition like as atmospheric phenomena and soil in Jeju region. (Key words : Jeju barnyard grass, Seeding date, Forage yield, Chemical composition)

• Magazine of the Korean Society of Agricultural Engineers
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• v.28 no.2
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• pp.31-41
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• 1986

Knowledge of the degree of yield reduction due to water stress at different crop growth stages in rice production is important for rational scheduling of irrigation during periods of insufficient water supply. Previous studies to determine the degree of yield reduction duo to water stress suffered from interruptions by rain during experiment. Also the findings did rot relate the degree of water stress to the soil water potential and water deficit status of rice plants. In this study, two years experiments were conducted using the high yielding rice varieties, an Indica x Japonica (Nampoong) and a Japonica variety(Choochung). These were grown in 1/200$^{\circ}$ plastic pots placed under a rainfall autosensing, sliding clear plastic roof facility to control rainfall interruptions. The results obtained were as follows. 1.The two varieties differed in the growth stage most sensitive to water stress as well as the degree of yield reductions. When rice plants were stressed to the leaf rolling score 4 and soil water potential of about - 20 bar at major crop growth stages which included heading, booting, non-effective tillering, panicle initiation and early tillering stages, the yield reductions in the Indica x Japonica variety were 58%, 34%, 27%, 22%, and 21%, respectively, whereas in the Japonica vairety they were 23%, 36%, 1%, 13% and 22%, respectively. This result show that the recommended drainage during non-effective tillering is valid only for the Japonica variety. Sufficient irrigation at booting, heading and early tillering stages are necessary for both varieties. 2.The two varieties showed visible wilting symptoms when the soil water potential dropped to about - 3.0 bar. The Japonica variety showed more leaf rolling than the Indica X Japonica. However, it had a higher retention of leaf water content and greater stomatal diffusive resistance. When the soil water potential dropped, the Japonica variety showed leaf rolling score (LRS) 1 at 0 soil-5. 0 bar and LRS 2 at 0 soil -6.0 bar while the Indica X Japonica showed LRS 1 at 0 soil - 5.5 bar and LRS 2at 0 Soil - 9.0 bar. The stomatal diffusive resistance was maximum at the second top leaf blade in both varieties at intermediate water stress of 0 soil - 4.5 bar. 3.The number of days that was required for the soil water potential to drop to-3. 0 bar and to - 20.0 bar after drainage of irrigation water from the 20cm deep silty clay loam soil in the pots were 6 and 13 days, respectively for booting stage, and 7 and 11 days, respectively for heading stage, 9 and 12 days, respectively for panicle initiation stage, and 12 and 19 days, respectively for early tillering stage. 4.Water stress during the early tillering stage recorded the longest delay in beading time, the largest reduction in panicle numbers and a substantial yield decrease of 20%. This calls for better water management to ensure the availability of water at this stage, particularly during drought periods. In addition, a reexamination of the conventional inter-drainage practice during the non-effective tillering stage is necessary for the high yielding Indica X Japonica varieties.

• Proceedings of the Korean Society of Crop Science Conference
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• 2017.06a
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• pp.279-279
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• 2017

In Korea, the single span unheated plastic house cultivated crops from autumn to spring of the following year, removed the plastic film and frame, cultivated rice, set up a plastic house again and cultivated crops. The crops in the greenhouse are utilized mainly for the production of leaf vegetables such as lettuce, leek, and fruit vegetables such as strawberry, watermelon, oriental melon, etc. and raising high income. Because, the production of these crops has characteristics requiring a lot of labor and it is difficult to produce horticultural crops at unheated plastic houses as the rural population ages. Therefore, we conducted a test to develop a crop planting system to cultivate crops in single span unheated plastic houses, although the utilization of labor is less than that of horticultural crops. The prior cropping cultivated three cultivars of sweet potatoes early, the second produced cultivated sweet potatoes, corn and soybeans. In the cultivation of the previous cropping, the sweet potatoes were harvested on the 113th day after planting on March 30th, the yield was 822 kg/10a for Pungwonmi, 1,377 kg/10a for Jinhongmi, 1,483 kg/10a for the Dahomi. Because of differences, the yield of Pungwonmi cultivar was less than that other cultivars and the yield of open field cultivations, we will expect further research. In the cultivation of the succeeding crops sweet potatoes were planted on July 27 and harvested 110 days later and investigated. The product yield of Pungwonmi cultivar was 1,024 kg/10a, and the Jinhongmi, Dahomi cultivars were not at economic level for sale and were necessary to review. In succeeding-crops, corn tested the Ilmichal cultivar, seeded on 27th July, harvested on October 11th. The day of silking was 45 days after sowing, the yield was 1,156 kg/10a, the goods rate was 100% level. The beans in the succeeding cultivation crop were sowed on 27th July, the early maturing of the varieties coming to Hwangeumol and Saeol cultivar, on 17th October, the late maturing soybean Daewonkong cultivar were harvested on October 21st. The yield of early maturing two cultivars was 214 kg/10a, Daewonkong was 257 kg/10a, and 100 seeds weight which were more than the early maturing beans were also heavy. When calculating these incomes price-wise according to the harvest time, we were able to consider the income in the order of corn, sweet potato and soybean from the second term crop. Various studies such as varieties, mulching method, moisture management, control environment management, etc. are considered necessary to develop cropping systems with sweet potato and field crops in future unheated plastic house.

• Proceedings of the Korean Society of Crop Science Conference
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• 2017.06a
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• pp.8-9
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• 2017

Soybean yield has been low and unstable in Japan and other areas in East Asia, despite long history of cultivation. This is contrasting with consistent increase of yield in North and South America. This presentation tries to describe perspective of breaking stagnation of soybean yield in East Asia, considering the factors of the different yields between regions. Large amount of rainfall with occasional dry-spell in the summer is a nature of monsoon climate and as frequently stated excess water is the factor of low and unstable soybean yield. For example, there exists a great deal of field-to-field variation in yield of 'Tanbaguro' soybean, which is reputed for high market value and thus cultivated intensively and this results in low average yield. According to our field survey, a major portion of yield variation occurs in early growth period. Soybean production on drained paddy fields is also vulnerable to drought stress after flowering. An analysis at the above study site demonstrated a substantial field-to-field variation of canopy transpiration activity in the mid-summer, but the variation of pod-set was not as large as that of early growth. As frequently mentioned by the contest winners of good practice farming, avoidance of excess water problem in the early growth period is of greatest importance. A series of technological development took place in Japan in crop management for stable crop establishment and growth, that includes seed-bed preparation with ridge and/or chisel ploughing, adjustment of seed moisture content, seed treatment with mancozeb+metalaxyl and the water table control system, FOEAS. A unique success is seen in the tidal swamp area in South Sumatra with the Saturated Soil Culture (SSC), which is for managing acidity problem of pyrite soils. In 2016, an average yield of $2.4tha^{-1}$ was recorded for a 450 ha area with SSC (Ghulamahdi 2017, personal communication). This is a sort of raised bed culture and thus the moisture condition is kept markedly stable during growth period. For genetic control, too, many attempts are on-going for better emergence and plant growth after emergence under excess water. There seems to exist two aspects of excess water resistance, one related to phytophthora resistance and the other with better growth under excess water. The improvement for the latter is particularly challenging and genomic approach is expected to be effectively utilized. The crop model simulation would estimate/evaluate the impact of environmental and genetic factors. But comprehensive crop models for soybean are mainly for cultivations on upland fields and crop response to excess water is not fully accounted for. A soybean model for production on drained paddy fields under monsoon climate is demanded to coordinate technological development under changing climate. We recently recognized that the yield potential of recent US cultivars is greater than that of Japanese cultivars and this also may be responsible for different yield trends. Cultivar comparisons proved that higher yields are associated with greater biomass production specifically during early seed filling, in which high and well sustained activity of leaf gas exchange is related. In fact, the leaf stomatal conductance is considered to have been improved during last a couple of decades in the USA through selections for high yield in several crop species. It is suspected that priority to product quality of soybean as food crop, especially large seed size in Japan, did not allow efficient improvement of productivity. We also recently found a substantial variation of yielding performance under an environment of Indonesia among divergent cultivars from tropical and temperate regions through in a part biomass productivity. Gas exchange activity again seems to be involved. Unlike in North America where transpiration adjustment is considered necessary to avoid terminal drought, under the monsoon climate with wet summer plants with higher activity of gas exchange than current level might be advantageous. In order to explore higher or better-adjusted canopy function, the methodological development is demanded for canopy-level evaluation of transpiration activity. The stagnation of soybean yield would be broken through controlling variable water environment and breeding efforts to improve the quality-oriented cultivars for stable and high yield.

• Asian-Australasian Journal of Animal Sciences
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• v.17 no.10
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• pp.1383-1389
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• 2004

The nutritive value and utilization of whole crop rice silage (WCRS), Hamasari, at yellow mature stage was determined by three studies. In first study, chemical composition, in vivo digestibility and metabolizable energy (ME) content of WCRS was determined by Holstein steers. WCRS contains 6.23% CP, its digestibility is 48.4% and estimated TDN is 56.4%. Its ME content was 1.91 Mcal/kg DM. Gross energy (GE) retention (% of GE intake) in steers is only 22.7% most of which was lost through feces (44.7% of GE intake). It takes 81 minutes to chew a kg of WCRS by steers. In another study, the effect of Hamasari at yellow mature stage at three stages of lactation (early, mid and late lactation) and two levels of concentrate (40 or 60%) on voluntary intake, ME content and ME intake, milk yield and composition using lactating Holstein dairy cows were investigated. Total intake increased with the concentrate level in early and mid lactation, but was similar irrespective of concentrate level in late lactation. WCRS intake was higher with 40% concentrate level than with 60% concentrate. ME intake by cows increased with the concentrate level and WCRS in early lactating cows with 40% concentrate can support only 90% of the ME requirement. Milk production in accordance with ME intake increased with the increase in concentrate level in early and mid lactating cows but was similar in late lactating cows irrespective of concentrate level. Fat and protein percent of milk in mid and late lactating cows were higher with for 60% concentrate than 40%, but reverse was in early lactating cows. Solids-not-fat was higher with for 60% concentrate than 40% concentrate. Finally in situ degradability of botanical fractions such as leaf, stem, head and whole WCRS, Hamasari at yellow mature stage was incubated from 0 to 96 h in Holstein steers to determine DM and N degradability characteristics of botanical fractions and whole WCRS. Both DM and N solubility, rate of degradation and effective degradability of leaf of silage was lower, but slowly degradable fraction was higher compared to stem and head. Solubility of DM and N of stem was higher than other fractions. The 48 h degradability, effective degradability and rate of degradation of leaf were always lower than stem or head. In conclusion, voluntary intake of silage ranged from 5 to 12 kg/d and was higher with low levels of concentrate, but milk yield was higher with high levels of concentrate. Fat corrected milk yield ranged from 19 to 37 kg per day. For consistency of milk, early lactating cows should not be allowed more than 40% whole crop rice silage in the diet, but late lactating cows may be allowed 60% whole crop rice silage.