• Korean Journal of Agricultural and Forest Meteorology
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• v.8 no.4
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• pp.229-241
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• 2006

Global air temperature has risen by $0.6^{\circ}C$ over the last one hundred years due to increased atmospheric greenhouse gases. Moreover, this global warming trend is projected to continue in the future. This study was carried out to evaluate spatial variations in rice production areas by simulating rice-growth and development with projected high resolution climate data in Korea far 2011-2100, which was geospatially interpolated from the 25 km gridded data based on the IPCC SRES A2 emission scenario. Satellite remote sensing data were used to pinpoint the rice-growing areas, and corresponding climate data were aggregated to represent the official 'crop reporting county'. For the simulation experiment, we used a CERES-Rice model modified by introducing two equations to calculate the leaf appearance rate based on the effective temperature and existing leaf number and the final number of leaves based on day-length in the photoperiod sensitive phase of rice. We tested the performance of this model using data-sets obtained from transplanting dates and nitrogen fertilization rates experiments over three years (2002 to 2004). The simulation results showed a good performance of this model in heading date prediction [$R^2$=0.9586 for early (Odaebyeo), $R^2$=0.9681 for medium (Hwasungbyeo), and $R^2$=0.9477 for late (Dongjinbyeo) maturity cultivars]. A modified version of CERES-Rice was used to simulate the growth and development of three Japonica varieties, representing early, medium, and late maturity classes, to project crop status for climatological normal years between 2011 and 2100. In order to compare the temporal changes, three sets of data representing 3 climatological years (2011-2040, 2041-2070, and 2071-2100) were successively used to run the model. Simulated growth and yield data of the three Japonica cultivars under the observed climate for 1971-2000 was set as a reference. Compared with the current normal, heading date was accelerated by 7 days for 2011-2040 and 20 days for 2071-2100. Physiological maturity was accelerated by 15 days for 2011-2040 and 30 days for 2071-2100. Rice yield was in general reduced by 6-25%, 3-26%, and 3-25% per 10a in early, medium, and late maturity classes, respectively. However, mid to late maturing varieties showed an increased yield in northern Gyeonggi Province and in most of Kwangwon Province in 2071-2100.

• Journal of The Korean Society of Grassland and Forage Science
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• v.16 no.2
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• pp.155-160
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• 1996

Spring sown oat crops were grown during early March to late June in 1993~1994. The crops were harvested at different stage of maturity to determine the yield performance, chemical components and net energy value of the plants for silage utilization. The pattern of dry matter accumulation, absolute growth rate(Abs. GR), leaf weight ratio(LWR), stalk diameter(SD) and other growth parameters were analysed to evaluate the suitability of the plant materials for ensiling. The effect5 of wilting treatment and formic acid addition on the quality of silage was also disscused during the experiments. Spring sown oat crops was evaluated as a suitable materials for whole plant silage making. The best qualitative oat silage was obtained at the stage of soti dough to hard dough, when the plant reached 32.2~35.7% in dry matter concentration. Spring sown oat produced 9.43 ton in DM basis, 5.79 ton in TDN and 57.550 MJ-NEL/ha in net energy lactation. Early harvesting of the oat corps needed wilting treatment of the material before ensiling. Under pre-witing treatment (1/2 day) and formic acid addition(0.3%) silage quality point of oat crops harvested at the bloom stage was improved from 58 to 84 point.

• Asian-Australasian Journal of Animal Sciences
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• v.22 no.2
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• pp.225-231
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• 2009

The objective of this experiment was to study the effects of grass maturity at harvest on the nutritive value of grass silage (GS) in relation to voluntary intake, digestibility, nitrogen (N) utilization and in sacco dry matter (DM) degradability. Silage was cut from a sward dominated by orchardgrass (Dactylis glomerata L.) at the late-vegetative (early-cut), internode elongation (mediumcut) and flowering (late-cut) stages of growth. The DM yield at harvest was the lowest for early-cut silage (5.4 t/ha) and increased to 6.5 and 7.0 t/ha for the medium and late-cut silage respectively. As the crop matured, the crude protein (CP) concentration decreased significantly (p<0.05) and there was a marked increase in acid detergent fiber (ADF) concentration (p<0.001). The three different silages were offered to four 18-month old Charolais wether sheep to measure the voluntary intake, in vivo digestibility and N retention over four 21-day periods in an incomplete changeover design. Silage degradability characteristics were determined using four fistulated sheep to measure DM degradability over 3, 6, 12, 24, 48 and 72 h. There was a linear decrease in the voluntary intake of silage fresh matter, DM, organic matter (OM) and neutral detergent fiber (NDF), digestibility of DM, OM, NDF, ADF and CP, and digestibility of OM in DM (Dvalue) ($P_L<0.01$) as harvesting of grass was delayed. Nitrogen intake, N output in urine, N output in faeces and N balance also linearly decreased ($P_L<0.01$) with postponed harvesting of grass for silage. DM degradability and effective degradability (ED) significantly decreased with increasing maturity of grass at harvest. The results suggest that harvesting date has a significant influence on the nutritive value of GS in terms of intake, digestibility, N balance and in sacco degradability in the rumen. It was concluded that early harvest GS ensured higher intake, digestibility, N intake and DM degradability in comparison with the medium and the late cut GS as a result of improved rumen N efficiency and utilization probably due to a better balance of available energy and protein.

• Korean Journal of Agricultural Science
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• v.45 no.1
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• pp.19-27
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• 2018

To study the effect of natural anti-microbial chemicals on the growth and quality of chili peppers, chitosan ($100mg/L^{-1}$), stevia ($250mg/L^{-1}$), and the mixture of both chemicals at the same concentration were sprayed after planting at 1-week interval throughout the experimental period. Plant height was measured twice after the $3^{rd}$ and $4^{th}$ applications. Plant height was numerically reduced in all chemical treatments compared to that of untreated control; however, there was no statistical difference between treatments. The fruit quality was examined at commercial maturity, and only minor differences were found in fruit color, length, and dry matter content between the treatments. Although a statistical difference was not present for soluble sugars levels, total phenolics, and capsaicin contents, yield in all chemical treatments significantly increased compared to untreated control. The effect on yield increase was greater at the late harvest season regardless of treatments. Total yield of 4 harvests was higher for the chitosan treatment than other treatments. During the experiment, the entire experimental field was waterlogged for 1 day due to sudden heavy rainfall, which resulted in the occurrence of bacterial browning disease in all treatments. The rate of disease occurrence and the degree of severity, however, were much lower in the chitosan treatment. In conclusion, the potential of chitosan as an alternative antimicrobial agent was confirmed in chili peppers in this study. Further research is required on stevia as an alternative chemical for disease control in chili peppers.

• KOREAN JOURNAL OF CROP SCIENCE
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• v.33 no.2
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• pp.174-181
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• 1988

A comparison was made the differences of growth and some yield components of two soybean ecotypes (summer and two autumn types) at different planting dates (15 April, 15 May, and 15 June) and also made the different patterns of dry matter accumulation of one summer type and two autumn types of soybeans at Agricultural Experiment Farm, College of Agriculture, Dankook University, Cheonan City, in 1987. [Planting date experiment] Days to emergence of four varieties were observed no difference. and, therefore, it was speculated that field observation of the difference of cold tolerence between varieties was difficult. Shortening rate of flowering clays as planting dates delayed was no different between two ecotypes, summer vs. autumn types of soybean. Summer types, DN82029-3 and ES18085-1, were observed not greater difference of days to maturity between early and late planting dates as compared with that of autumn types, Changyeobkong and Paldalkong. At late planting, summer types were observed more to hasten days to ripening due to high temperature in late growing season than that of autumn types. This caused to decrease somewhat greater rate of some yield componments, and finally yield as planting date delayed. As compared to autumn types, summer types, DN82029-3 and ES18085-1 showed longer stem height and lower airdry weight at late planting. [Dry matter accumulation pattern] Stem elongation after flowering of three varieties, DN82029-3, Changyeobkong and Danyeobkong, ranged 17 to 32 cm and increment of leaf area index 0.83-1.53. DN82029-3 reached 49 days faster in maximum total dry weight than that of autumn types, Changyeobkong and Danyeobkong. However. maximum total dry weight of DN82029-3 showed 50% to autumn types. At 15 May planting, summer type, day-neutrality, transfered faster into reproductive growth phase without enough growth of vegetative growth and also hastened ripening days, and thus lower dry matter accumulation and finally lower yield.

• KOREAN JOURNAL OF CROP SCIENCE
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• v.57 no.3
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• pp.310-315
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• 2012

The vegetable perilla is proved to be a late-maturing plant that flowers at the early of Oct. regardless of sowing time, so that the sowing time for seed production should be decided under consideration of maturity before beginning of frost. This experiment was carried out to determine the sowing date for seed production at greenhouse on late-maturing perilla cultivar, 'Ipdlkkae 1' in the middle region of Korea. The sowing dates were 8 times from May 6 to July 15 with an intervals of 10 days. As sowing date was delayed, the stem height, no. of nodes, no. of branches, no. of cluster per plant and no. of capsules per cluster were decreased. But as sowing was early, the lodging was occurred because of heavier growing. Days to flowering was linearly decreased about 0.86 day as affected by a day's delayed. But days from flowering to maturing was not significantly affected by sowing date. The grain yield was not significantly different among sowing from May 6 to June 15 and rapidly decreased the sowing after June 25 because of the reductions of no. of cluster and percent of ripened grain. Considering accumulative temperature, lodging, germination rate and grain yield, it is suggested that the sowing for seed production in late-maturing perilla cultivar should be finish before June 15 (transplanted at July 15) at greenhouse in the middle region of Korea.

• Korean Journal of Organic Agriculture
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• v.23 no.3
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• pp.523-534
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• 2015

Twenty four Holstein steers (average body weight $714{\pm}13.60kg$) were used in this experiment to determine the effect of supplementing of microbial culture and coated vitamin-C on growth performances and carcass characteristics in finishing Holstein steers. Holstein steers were randomly assigned to feeding groups of control group (Con, 12 kg of basal diet/head/day), microbial culture group (MC, 12 kg of basal diet + 30 g of microbial culture/head/day) and coated vitamin-C group (CVC, 12 kg of basal diet + 10 g of coated vitamin-C/head/day). MC and CVC groups were higher in ADG compared to control (P<0.05). FCR was also lower in MC and CVC groups than control group (P<0.05). Back fat thickness, rib-eye area, marbling score, meat color and yield index were not changed by supplementing microbial culture and coated vitamin-C. MC group was higher for maturity compared to control and CVC group (P<0.05). CVC group was higher for fat color compared to control and MC group (P<0.05). Based on the results obtained from the current study, supplementation of microbial culture and coated vitamin-C as an alternative to antibiotic might increase growth performances and enhance carcass characteristics in finishing Holstein steers. However, more studies are needed to find out the optimum supplementing period of microbial culture or coated vitamin-C for high quality meat production from Holstein steers.

• Korean Journal of Agricultural Science
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• v.8 no.2
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• pp.164-170
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• 1981

In order to develop feed source from shrubby area of mountain for dairy cow, some shrub and grass were harvestied by stage of maturity and analyzed the chemical composition of herbage, and fed to milking cow to know the effect on the body weight and milk production. And the results were summarized as follow. 1. The dry matter content of green herbage was ranged average 25~50% and Smilax china and Cocculus thunbergii were the lowerest as 26.25% and 26.36% respectively and Quercus serrata was the highest as 47.19% of the species. 2. The average protein content of herbage was widely ranged from about 5% to 20%. And Pueraria thunbergiana and Albizzia julibrissin were higher as nearly 20% and Miscanthus sinesis and Arundinella hirta were lower as nearly 5~7%. 3. The average crude fiber content of most species was rarged 20~30%. And Corylus heterophylla and Smilax china were lower as about 20% and Miscanthus sinensis and Arundinella hirta were higher as nearly 37%. 4. The crude protein content of most species was decreased and the fiber content was increased by abvanced the stage of maturity. And also moisture content of green herbage was decreased by seasonal changed. 5. When air dry herbage of 5 kg per head/day was substituted for rice straw, the weight of cows and milk yield and solid not fat content were Slightly increased.

• Asian-Australasian Journal of Animal Sciences
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• v.7 no.3
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• pp.383-387
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• 1994

Six heifers each of $F_1$, $F_2$, $F_3$, $F_4$ H. Friesian $\times$ Sahjwal halfbreds and pure Sahiwal with overall average initial age and live weight of $315.6{\pm}134.8 days$ and $143.8{\pm}48.5kg$, respectively were used for this study. The under trial animals were fed according to N.R.C. (1978). The overall average age at maturity, first conception and first calving was $563.8{\pm}116.8$, $675.8{\pm}135.6$ and $956.8{\pm}149.8days$ with live weights as $302.2{\pm}58.6$, $342.6{\pm}41.5$ and $433.9{\pm}38.1kg$, respectively. The overall 305 days and total milk yield for 1st lactation was $2,729.0{\pm}669.3$ and $2,992.7{\pm}377.5litre$ while the FCM (at 4%) was $2,934.2{\pm}410.8litre$. The lactation length was $336.6{\pm}69.6days$. The fat and solids not fat contents were $4.5{\pm}0.2$ and $8.2{\pm}0.3percent$, respectively. The milk production in Sahiwal cows was significantly lower than crossbred cows. The services per conception were $2.5{\pm}1.3$. The overall per head per day consumption of DM, TCP and ME was $10.9{\pm}1.2kg$, $1,399{\pm}199gm$ and $22.6{\pm}2.4 M.Cal.$, respectively. The overall milk producing efficiency for the production of one litre of FCM was $1.12{\pm}0.15kg$ of DM, $142.2{\pm}17.76gm$ of TCP and $2.31{\pm}0.27M.Cal.$ of energy while the feeding cost was Rs. $1.46{\pm}0.22$ per litre of FCM produced. The feeding cost per litre FCM was significantly higher in Sahiwal and $F_2$ than in other genetic groups.

• KOREAN JOURNAL OF CROP SCIENCE
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• v.37 no.2
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• pp.123-133
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• 1992

This study was conducted to clarify progressed changes of plant types and the effects of the physiological and ecological components on improving ideotype of winter wheat. 12 wheat varieties were planted at the experimental farm of Wheat and Barley Research Institute in Suwon in 1990. As results of intensive wheat breeding for early maturity since 1959, heading, flowering and maturing dates have been shortened by 17, 15 and 14 dagys, respectively. The shortened days from sowing to heading and from heading to flowering contributed to the early maturity to improved. Physiological factors associated with heading time of wheat could be reprsented by growth habit, photoperiod responses, earliness in narrow sense and winter hardiness. For improving an early maturity of winter wheat, it would desired to maintain some degree of winter habit(III-IV), and recombination of more insensitivity to short day length and more shortened earliness in narrow sense than that of Saemil and Chugoku 81, and higher degree of winter hardiness. For improving the early maturity the more effective way must be of shortened days from sowing to heading, and days from flowering to maturity than days from heading to flowering. Ideotype of wheat will be desired to recombine two semi-dwarf genes with erect plant type being about 70-80cm, less stem elongation by late spring, long spike and many grains per spikelet. Average spike weight ratio was about 45-49% in high-yielding varieties, stem fresh weight was lighter, but spike fresh weight was heavier in new one while leaf fresh weight was similar to each other during the maturing periods. Average spike dry weight ratio was higher about 40～48%, and stem and leaf blade dry weights were lower in the newly bred varieties. Stem dry weight was heavier than spike or leaf dry weight in the old varieties of Yungkwang, Jangwang and Jinkwang. Leaf area index for the varieties showed normal distribution curve as the maximum point in booting stage. The maximum point of this curve come in early maturing wheat, and late in old one. The maximum points of LAI were 6.4～6.8 in the high-yielding varieties. Totals of LAI in each period investigated of old one were higher than those of newly bred being 24.6～28.8. Chlorophyll content of the high-yielding varieties of Chokwang, Geurumil and Saemil as higher than that of the old varieties Jangkwang, Jinkwang, Wonkwang and Sinkwang from regrowing period to April 21. after then slightly and even after heading. Net assimilation rate (NAR) was higher in high-yielding varieties with good plant type, and lower in old ones. Grain yield of the newly released varieties increased rapidly but slowly in the old ones. Change in water content of grain at the growing stage in newly bred was lower than that of the old bred. Diminishing rate of water content of grain in establishment per day was 1.2% average that of the old varieties including Yungkwang was 1.5%, and those of the newly bred including Chokwang were 0.9～1.1%. Chokwang, Naemil, and Saemil were the highest-yielding varieties of the Korean cultivars. Yields were increased by spikes per m$^2$, grain weight for the varieties bred in Suwon, and by spikes per m$^2$ for the varieties bred in Milyang.