Understanding changes in fermentation characteristics and microbial populations of forage silage during ensiling is of interest for improving the nutrient value of the feed for ruminants. This study was conducted to investigate the changes in fermentation characteristics and bacterial communities of whole crop rice (WCR) silage during the ensiling period. The chemical compositions, pH, organic acids and bacterial communities were evaluated at 0, 3, 6, and 12 months after ensiling. The bacterial communities were classified at both the genus and species levels. The dry matter content of WCR silage decreased with the length of storage (p<0.05), but there was no significant difference in crude protein and NDF contents. Following fermentation, the pH level of WCR silage was lower than the initial level. The lactic acid content remained at high levels for 3 to 6 months after ensiling, followed by a sharp decline at 12 months (p<0.05). Before fermentation, the WCR was dominated by Weissella (30.8%) and Pantoea (20.2%). Growth of Lactiplantibacillus plantarum (31.4%) was observed at 3 months after ensiling. At 6 months, there was a decrease in Lactiplantibacillus plantarum (10.2%) and an increase in Levilactobacillus brevis (12.8%), resulting in increased bacteria diversity until that period. The WCR silage was dominated by Lentilactobacillus buchneri (71.2%) and Lacticaseibacillus casei (27.0%) with a sharp reduction in diversity at 12 months. Overall, the WCR silage maintained satisfactory fermentation quality over a 12-month ensiling period. Furthermore, the fermentation characteristics of silage were found to be correlated to bacterial microbiome.

This study was to evaluate the values of Korean native sweet sorghum as a new feed crop for ruminants. Sweet sorghum was the Muan native species (Bioenergy Crop Research Center, National Institute of Crop Science), and cultivated from May to October 2021 at Sangji University (Wonju-si, Gangwon-do, Korea). There were a non-treated group (Con), a recommended amount treatment (RD) and a treatment with double the recommended amount (Double RD) by an oil cake fertilizer. Plant height was measured at weekly intervals for 12 weeks after planting sweet sorghum seedlings, and was a significant difference in the order of Double RD, followed by RD and Con in 7 weeks (p<0.05). Feed values and sugar contents were measured in 7, 9, and 11 weeks. Crude protein of Double RD was higher than that of the other treatments in 7 and 9 weeks (p<0.05). Crude fat was higher at Double RD than the other one in 9 weeks (p<0.05). ADF and NDF of Double RD were higher than the other one (p<0.05). When it was compared to corn and sudangrass hybrids grown on farms, Crude protein was lower in sweet sorghum than other crops (p<0.05), and crude fat was higher in sweet sorghum than corn (p<0.05). Crude fiber, ADF and NDF were higher in sweet sorghum compared to corn and sudangrass (p<0.05). The sugar contents of sweet sorghum were 4.07 ± 0.12∼7.63 ± 0.21 brix, and showed higher than corn and sudangrass hybrid (p<0.05). The rumen in situ digestibility of sweet sorghum was 30.73∼38.13% at the 9th and 11th weeks, and showed higher than that of corn and sudangrass hybrids (p<0.05). Therefore, it is considered that Korean native sweet sorghum has sufficient value as a new forage crop for ruminants, and good value as yield, nutrients and digestibility, when the grass height is 273.33~332.50 cm.

This study was conducted to estimate the effect of different cutting lengths on fermentation characteristics and aerobic stability of whole crop rice (WCR) silage. The WCR was harvested at the yellow ripe stage (43.7%, DM), and then cut at 5 (R05), 10 (R10), and 20 cm (R20) of the theoretical length of cut with no cut WCR (R60). Each forage was ensiled into 20 L mini bucket silo (5 kg) for 150 days in quadruplicates. The cutting lengths were not affected the chemical compositions of WCR silage (p > 0.05). The pH (p < 0.001) and concentration of ammonia-N (p = 0.022) in WCR silage were increased linearly with the increase of cutting length. The concentration of lactate had quadratic effect (p = 0.007), which was highest in R20 silage (p < 0.05). The concentration of acetate was increased linearly (p = 0.014), but the concentration of butyrate was decreased linearly (p = 0.033). The lactic acid bacteria count was decreased linearly (p = 0.017), and yeast count had quadratic effect (p = 0.009), which was the highest in R20 silage (p < 0.05). Aerobic stability had strong quadratic effect (p < 0.001), which was the highest in R20 silage (p < 0.05). In conclusion, R60 silage had highest pH by a linear increase of ammonia-N concentration and led to low aerobic stability. While R20 silage had the lowest pH by high lactate concentration and led to high aerobic stability.

This study was conducted to compare the agronomic characteristics and productivity according to the species and varieties of winter forage crops in reclaimed land. Winter forage crops used in this study were developed in National Institute of Crop Science, RDA. Oats (‘Samhan’, ‘Jopung’, ‘Taehan’, ‘Dakyung’ and ‘Hi-early’), forage barley (‘Yeongyang’, ‘Yuyeon’, ‘Yujin’, ‘Dacheng’ and ‘Yeonho’), rye (‘Gogu’, ‘Jogreen’ and ‘Daegokgreen’) and triticale (‘Shinyoung’, ‘Saeyoung’, ‘Choyoung’, ‘Sinseong’, ‘Minpung’ and ‘Gwangyoung’) were planted in the reclaimed land of Sihwa district in Hwaseong, Gyeonggi-do in the autumn of 2018 and cultivated using each standard cultivation method, and harvested in May 2019(oat and rye: 8 May, barley and triticale: 20 May.) The emergency rate was the lowest in rye (84.4%), and forage barley, oat and triticale were in similar levels (92.8 to 98.8%). Triticale was the lowest (416 tiller/㎡) and oat was the highest (603 tiller/㎡) in tiller number. Rye was the earliest in the heading date (April 21), triticale was April 26, and oat and forage barley were in early May (May 2 and May 5). The plant height was the highest in rye (95.6 cm), and triticale and forage barley was similar (76.3 and 68.3cm) and oat was the lowest (54.2 cm). Dry matter(DM) content of rye was the highest in the average of 46.04% and the others were similar at 35.09∼37.54%. Productivity was different among species and varieties, with the highest dry matter yield of forage barley (4,344 kg/ha), oat was similar to barley, and rye and triticale were lowest. ‘Dakyoung’ and ‘Hi-early’ were higher in DM yield (4,283 and 5,490 kg/ha), and forage barley were higher in ‘Yeonho’, ‘Yujin’ and ‘Dacheng’ varieties (4,888, 5,433 and 5,582 kg/ha). Crude protein content of oat (6.58%) tended to be the highest, and TDN(total digectible nutrient) content (63.61%) was higher than other varieties. In the RFV(relative feed value), oats averaged 119, while the other three species averaged 92∼ 105. The weight of 1,000 grain was the highest in triticale (43.03 g) and the lowest in rye (31.61 g). In the evaluation of germination rate according to the salt concentration (salinity), the germination rate was maintained at about 80% from 0.2 to 0.4% salinity. The correlation coefficient between germination and salt concentration was high in oat and barley (-0.91 and -0.92) and lowest in rye (-0.66). In conclusion, forage barley and oats showed good productivity in reclaimed land. Adaptability is also different among varieties of forage crops. When growing forage crops in reclaimed land, the selection of highly adaptable species and varieties was recommended.

본 연구는 고부가가치 약용작물인 잔대(Adenophora triphylla var. japonica Hara)의 종자 형태특성과 휴면 유형을 조사하고, 발아율 향상을 위한 소독제와 광질을 선발하기 위해서 수행되었다. 종자 소독은 증류수(대조구), NaClO 4%, H2O2 4%와 benomyl 500mg·L-1를 이용하여 실시하였으며, 광질처리는 암조건(control I), 형광등 (control II), LEDs[red, blue, green, RB LEDs(red:blue = 8:2, 6:4, 4:6, 2:8)]를 광주기 12/12(light/dark), 광도 150μmol·m-2·s-1 photosynthetic photon flux density로 설정 하였다. 잔대 종자는 emryo (E):seed (S) ratio가 0.4로 미숙배 종자지만 30일 이내에 발아가 되며, 침지 6시간 만에 포화상태에 도달하였다. 종자 소독 후 benomyl 처리에서 곰팡이 발생이 유의적으로 억제되었으며, 최종 발아 율이 87%로 가장 높았다. 적색광에서 최종 발아율이 92%로 가장 높았으며, 일일평균발아수는 R2B8에서 가장 적었다. 따라서 잔대 종자는 휴면이 거의 없으며, benomyl 소독제와 적색광이 발아율 향상에 효과적이여, 향후 약용작물 잔대 재배에 이용가치가 높을 것이라 판 단된다.

This experiment was conducted to investigate the effect of whole crop rice (WCR) based TMR on growth performance and carcass characteristics of Hanwoo steers. WCR “Yeongwoo”was harvested at yellow ripen stage and ensiled for 60 days. The crude protein (CP), acid detergent fiber (ADF), neutral detergent fiber (NDF), in vitro dry matter digestibility (IVDMD) and total digestible nutrient (TDN) content was 8.4 %, 28.0 %, 53.8 %, 72.4 % and 66.8 %, respectively. For silage quality, pH was 4.37 and lactic and butyric acid content were 2.84 and 0.04 % in DM. Sixteen Hanwoo steers (8-mon-old) were allocated into either a control (commercial TMR) and WCR-TMR (WCR-based TMR) group. The TMR were fed according to the feeding stage phase: growing (Initiate∼14 month), early fattening (15 month∼21 month) and late fattening (22 month∼30 month). The body weight of control group increased (P<0.05) until early fattening stage, but late growing stage of WCR-TMR group was higher than that of control (P<0.05). Average daily gain (ADG) was significantly greater (P<0.05) in WCR-TMR group (total 0.78 kg/head) compared to control (total 0.66 kg/head) except for late fattening stage. The marketing weight and carcass weight were higher in WCR-TMR group (726 vs 765 kg; 417.8 vs 450.4 kg). The back fat thickness (11.75 vs 13.00 mm), Longissimus dorsi area (88.00 vs 89.88 ㎠) and yield index (65.87 vs 64.30) were not different between the two groups (P>0.05) and also no difference in meat yield grade (A : B : C = 2 : 4 : 2). Marbling score (4.00 vs 4.13), meat color (4.75 vs 4.75), fat color (3.13 vs 2.88), texture (1.25 vs 1.50) and maturity (2.00 vs 2.00) were not significant difference between the two groups and meat quality grade (1++:1+:1:2:3=0:2:4:2:0) was also not different. In conclusion, TMR feeding based on WCR silage showed superiority in carcass yield and ADG compared to control TMR. It is considered that the use of WCR for feed is a necessary option for the substitution of the imported forages and the government's policy for rice production adjustment.

본 연구는 기존에 재배된 바 없었던 암대극을 새로운 관상식물로 개발하고자, 절화 특성 평가를 실시하였다. 2017년 3월과 4월, 제주도에 자생하고 있는 암대극을 채취한 후, 수분흡수, 절화수명, 노화 과정 등 절화수명 특성을 평가하였다. 또한 sucrose 농도, 절화길이, pH 농도, 저장온도에 따른 절화 특성을 조사하였다. 본 실험은 국립수목원 유용식물증식센터의 Phyto-garden system(12h photoperiod, 25℃, 70% RH)과 실온(23℃, 44% RH)에서 수행하였고 2~3일 간격으로 수분흡수량, 생체중, 절화수명을 측정하였다. 실험 환경에 따른 연구에서 실온(14.4일) 보다 phyto-garden system(42.4일)의 절화 수명이 약 3배 더 길었고, 절화길이에 따른 연구에서는 절화수명이 20cm, 15.2일, 40cm, 17.4일로 나타났다. Sucrose 농도에 따른 연구에서는 처리에 따른 절화수명 증진 효과는 없었고, pH에 따른 연구의 절화수명은 pH 5, 15.6일, pH 6, 13.4일, pH 7, 13.1일, 증류수, 14.8일이었다. 저장온도에 따른 실험에서, 절화수명은 4℃, 83일, 10℃, 41.2일, 15℃, 35.5 일, 20℃, 17.4일, 실온, 14.4일이었는데, 온도가 감소할수록 절화수명이 길어짐을 알 수 있었다. 결론적으로, 암대극은 비교적 광도와 습도가 높은 환경과 절화길이가 길고 저장온도가 낮을수록 수명이 오래 유지되는 것을 알 수 있었다.

This study was performed to persue the optimal cropping system for the cultivation of upland crops on rice-paddy field. It was conducted at Anseong-si Gyeonggi province of Korea from 2013 to 2015. In order to investigate growth and yield characteristics of sorghum under different paddyupland rotation systems, varieties of Nampungchal, Moktaksusu, Aneunbangisusu and Hwanggeumchal were examined. Four paddy-upland rotation systems of upland (1 year)-rice paddy (1 year)-upland (1 year), rice paddy (1 year)-rice paddy (1 year)-upland (1 year), rice paddy (1 year)-upland (1 year)- upland (1 year) and upland (1 year)-upland (1 year)-upland (1 year) systems were tested. The pH of upland (1 year)-upland (1 year)-upland (1 year) system exhibited the highest (pH 6.68), showing a tendency that the longer the upland years, the higher the soil pH. Among four paddy-upland rotation systems, the higher exchangeable Ca was obtained from upland (1 year)-upland (1 year)-upland (1 year) system (5.03 cmol+/kg), showing a tendency that the longer the upland years, the higher the exchangeable Ca. Upland (1 year)-upland (1 year)-upland (1 year) system exhibited the shortest days from seeding to heading (68 days) among four paddy-upland rotation systems and Hwanggeumchal showed the shortest days from seeding to heading (62 days) among four varieties. In the average of culm length and ear length, there was no significance between four paddy-upland rotation systems, but Moktaksusu (151.7 cm in culm length) and Aneunbangisusu (27.4 cm in ear length) exhibited the highest culm length and ear length respectively. The highest grains per ear was obtained from upland (1 year)-upland (1 year)- upland (1 year) system (1,068 grains) among four paddy-upland rotation systems and Nampungchal (1,107 grains) among four varieties. In average yield per 10a among four rotation systems, rice paddy (1 year)-upland (1 year)-upland (1 year) system produced the highest yield (221.2 kg/10a).

This study was conducted to evaluate the possibility of expanding the usage of whole crop silage from beef cattle and dairy cow to hogs and chickens. For this purpose, a crushing device was developed to crush whole crop silage. The crushed silage was sealed, and analyzed for its feed value. The silage varieties used for the experiment included Saessal barley and Geumgang wheat. Whole crop barley and wheat were crushed in the crushing system as a whole without separating stems, leaves, grains, etc.. When the crushed whole crop silages (CWCS) were analyzed, full grain, grains above 10 mm in size, grains 5～10 mm in size, and grains below 5 mm in size accounted for, 20%, 4%, 27%, and 49 %, respectively. In order to facilitate the fermentation of CWCS, inoculated some fermenter into each CWCS sample (barley or wheat). As control, another set of sample was not inoculated. Crude protein (CP), ether extract (EE), crude fiber (CF), neutral detergent fiber (NDF), acid detergent fiber (ADF), lignin, cellulose content, total digestible nutrient (TDN), and relative feed value (RFV) of fermenter-inoculated Saessal barley were 2.45 %, 1.61%, 8.95%, 16.94%, 9.52%, 1.01%, 8.51%, 81.38%, and 447.5%, respectively. The CP, EE, CF, NDF, ADF, lignin, cellulose content, TDN, and RFV in the other sample of Saessal barley without inoculation of fermenter were 2.57%, 1.62%, 9.61%, 18.25%, 10.13%, 1.10%, 9.04%, 80.90%, and 412.9%, respectively. The CP, EE, CF, NDF, ADF, lignin, cellulose content, TDN, and RFV of fermenter-inoculated Geumgang wheat sample were 2.43%, 1.27%, 10.99%, 19.49%, 11.23%, 1.46%, 9.77%, 80.03%, and 382.6%, respectively. The CP, EE, CF, NDF, ADF, lignin, cellulose content, TDN, RFV of the other set sample of Geumgang wheat sample without the inoculation of fermenter were 2.28%, 1.44%, 10.08%, 18.02%, 10.44%, 1.26%, 9.18%, 80.65%, and 416.9%, respectively. The TDN and RFV content in the fermenter-inoculated Saessal barley were 81.38% and 447.5%, respectively, while the one in the fermenter-inoculated Geumgang wheat were 80.03% and 382.6% respectively. When the feed value of whole crop barley and wheat silage without crushing process was compared to the feed value of whole crop barley and wheat silage made from crushing system, the latter appeared to be higher than the former. This could be due to the process of sealing the crushed silage which might have minimized air content between samples and shortened the golden period of fermentation. In conclusion, these results indicate that a crushing process might be needed to facilitate fermentation and improve the quality of silage when making whole crop silage.

본 연구는 새로 조성된 간척지에서 사료맥류 종자의 안정생산을 위한 적정 파종량을 구명코자 2011년부터 2013년까지수행하였다. 청보리와 트리티케일은 ha당 200, 300 및 400 kg호밀과 귀리는 ha당 100, 200 및 300 kg을 파종하고 토양화학성과 작물별 수량성을 조사 하였다. 사료맥류의 출현율과 입모율은 호밀, 트리티케일, 청보리, 귀리 순으로 높았다. 사료맥류 종실의 질소 함량은 트리티케일, 호밀, 보리, 귀리 순으로높았고 트리티케일과 호밀은 파종량 증가에 따라 질소함량이높아지는 경향을 나타냈다. 사료맥류의 종실수량은 트리티케일, 귀리, 호밀, 청보리 순으로 많았다. 파종량에 따른 종실수량은 청보리와 트리티케일은 ha당 300 kg에서, 호밀과 귀리는200 kg에서 많았다. 수량구성요소 중 m2당 이삭수가 종실수량에 큰 영향을 미쳤고 수당립수와 천립중은 파종량 감소에 따라증가하는 경향을 나타냈다. 연구 결과 새로 조성된 간척지에서동계 사료맥류 종자의 안정생산을 위한 적정 파종량은 ha당 청보리는 320 kg, 트리티케일은 290 kg, 호밀은 220 kg, 귀리는210 kg으로 나타났다.

An experiment was carried out to determine the homofermentative activity of Lactobacillus plantarum KCC-10 and KCC-19 on the ensiling of whole crop barley (WCB). The crude protein in the silages was slightly higher in the KCC-10 and KCC-19 treatments compared to the control, but there was no significant difference between the two inoculant-treated silages. Nutrient parameters such as acid detergent fiber, neutral detergent fiber and in vitro dry matter digestibility in L. plantarum KCC-10 and KCC-19 treated silages did not differ from those in the control silage. The lactic acid content increased in KCC-10 and KCC-19 treated silage when compared with the control silage but the contents of acetic acid and butyric acid produced in KCC-10 and KCC-19 treated silages were similar with the control silage. Further, the number of lactic acid bacteria (LAB) in KCC-10 treated silage demonstrated a significant increase when compared to the control. Especially, KCC-19 treated silage showed greater lactic acid bacterial growth potential. Other microbes such as yeast and fungi were not detected in KCC-10 and KCC-19 treated WCB silages. Hence, this study suggests that the addition of L. Plantarum KCC-10 and KCC-19 to the WCB silage can improve fermentation quality for the production of high-quality silage.

The in vitro experiment was conducted to ensure the supplemental level of spent Flammulina velutipes mushroomsubstrates (SMS) as an energy source in manufacturing of whole crop sorghum silage. Sorghum harvested at heading stage wasensiled with spent mushroom substrates of 20% (S-20), 40% (S-40) and 60% (S-60) as fresh matter basis for 6 week. Theexperiment was conducted by 3, 6, 9, 12, 24, 48 hrs of incubation time with 3 replications. The silages were evaluatedfermentation characteristics and dry matter digestibility (DMD) in vitro. The pH of in vitro solution was inclined to decrease withelapsing the incubation time, and that of the S-20 was significantly (P<0.05) lower than the other treatment at 48 hr ofincubation. Gas production was greater (P<0.05) in the S-20 than the other treatments at 6 and 12 hrs of incubation. Themicrobial growth in vitro was inclined to decrease following 24 hr of incubation, and thereafter sustained the similar levels. Invitro dry matter digestibility (IVDMD) was lowered by increasing the supplemental level of spent mushroom substrate, and was alow level in the S-60 throughout whole incubation time. Althoughthe IVDMD for S-40 was steadily increased from 9 hr ofincubation and reached to similar level with the S-20 at 48 hourof incubation, however SMS for whole crop sorghum silagefermentation might as well add about 20 to 30% in fresh matterbasis when considering DMD.

본 연구는 우리나라에서 여름철 조사료자원으로서 난지 형목초의 재배 가능성을 검토하고 저 수분 저장 조사료 생 산에 적합한 여름철 사료작물을 선발하기 위하여 난지형 목초의 생육특성, 사초 생산성 및 사료가치를 평가하기 위 하여 충남 천안에서 2013년 5월부터 2014년 12월까지 수 행하였다. 난지형 화본과 목초인 버뮤다그라스 “Tifton 85”, “Cheyenne Ⅱ”, “Mohawk” 3품종, 테프그라스 “Tiffany”, “Emerald” 품종과 클라인그라스 “Selection 75” 품종을 매 년 5월말부터 6월 초순 사이에 파종하였다. 버뮤다그라스 와 클라인그라스의 출현 소요일은 파종 후 11~12일 정도 소요되었으며 테프그라스는 파종 후 2일정도 소요되는 것 으로 나타났다. 버뮤다그라스는 시험기간 동안 전혀 출수 가 이루어지지 않았으며, 테프그라스는 7월 10일경, 클라인 그라스는 7월 24일경에 출수기에 도달하였다. 난지형 목초 의 사초생산성은 버뮤다그라스 Tifton 85 품종의 건물 및 TDN 수량이 각각 13,159, 7,764 kg/ha으로 가장 높게 나타 났으며 테프그라스가 가장 낮은 것으로 나타났다. NDF와 ADF 함량은 초종 간에 큰 차이가 나타나지 않았으며, 단 백질 함량은 버뮤다그라스가 평균 11.5%로 난지형 목초 중 가장 높게 나타났다. 총 가소화영양소(TDN) 함량은 테 프그라스 Tiffany 품종이 63.6%로 가장 높게 나타났으며 in vitro 건물소화율은 초종 간에 큰 차이를 보이지 않았다. 이상의 결과를 종합해보면 우리나라에서 여름철 조사료 자 원으로 난지형 목초의 재배 및 이용 가능성이 충분하였으 며, 월동이 가능한 제주도와 남부지방에서는 영년생 방목 초지용으로 활용성이 높고, 월동이 불가능한 중북부 지역 에서는 1년생 여름철 사료작물로 이용하는 것이 우리나라 에서 난지형 목초를 효율적으로 이용할 수 있는 방법으로 사료된다.

본 연구는 우리나라에서 여름철 조사료자원으로서 난지형목초의 재배 가능성을 검토하고 저 수분 저장 조사료 생산에 적합한 여름철 사료작물을 선발하기 위하여 난지형목초의 생육특성, 사초 생산성 및 사료가치를 평가하기 위하여 충남 천안에서 2013년 5월부터 2014년 12월까지 수행하였다. 난지형 화본과 목초인 버뮤다그라스 “Tifton 85“, “Cheyenne II“, “Mohawk“ 3품종, 테프그라스 “Tiffany“, “Emerald“ 품종과 클라인그라스 “Selection 75“ 품종을 매년 5월말부터 6월 초순 사이에 파종하였다. 버뮤다그라스와 클라인그라스의 출현 소요일은 파종 후 11~12일 정도 소요되었으며 테프그라스는 파종 후 2일정도 소요되는 것으로 나타났다. 버뮤다그라스는 시험기간 동안 전혀 출수가 이루어지지 않았으며, 테프그라스는 7월 10일경, 클라인그라스는 7월 24일경에 출수기에 도달하였다. 난지형 목초의 사초생산성은 버뮤다그라스 Tifton 85 품종의 건물 및 TDN 수량이 각각 13,159, 7,764 kg/ha으로 가장 높게 나타났으며 테프그라스가 가장 낮은 것으로 나타났다. NDF와 ADF 함량은 초종 간에 큰 차이가 나타나지 않았으며, 단백질 함량은 버뮤다그라스가 평균 11.5%로 난지형 목초중 가장 높게 나타났다. 총 가소화영양소(TDN) 함량은 테프그라스 Tiffany 품종이 63.6%로 가장 높게 나타났으며 in vitro 건물소화율은 초종 간에 큰 차이를 보이지 않았다. 이상의 결과를 종합해보면 우리나라에서 여름철 조사료 자원으로 난지형 목초의 재배 및 이용 가능성이 충분하였으며, 월동이 가능한 제주도와 남부지방에서는 영년생 방목초지용으로 활용성이 높고, 월동이 불가능한 중북부 지역에서는 1년생 여름철 사료작물로 이용하는 것이 우리나라에서 난지형 목초를 효율적으로 이용할 수 있는 방법으로 사료된다.