• 한국초지조사료학회지
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• 제7권2호
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• pp.71-78
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• 1987

본 실험은 파종방법, 배수화도 및 여름철 예취관리가 오차드그라스 채초지의 목장건물수량, 고사물량, 초지의 잡초발생 및 피복율에 미치는 영향을 조사하기 위하여 심험설계는 주구를 조파와 산파로 하고 세구를 배수랑호구와 배수불랑구로 하였으며, 세세구는 장마전 예취구와 장마후 예취구를 두어 세세구 배치 3반후으로 하여 1983년 9월부터 1984년 10월까지 실시하였던바 얻어진 결과는 다음과 같다. 1. 초지의 목장건물수량은 1회 예취시에는 처리간에 차이가 없었으나 2회와 3회 예취시에는 장마전 예취구가 장마후 예취구에 비하여 수량이 높았고 ($P{\le}0.01$) 3회예취시에는 조파구가 산파구에 비하여 수량이 높았다. $P{\le}0.05$. 2. 목장의 고사물량은 2회예취시에만 발생하였는데 장마전 예취구에서는 발생하지 않았는데 반해 장마후 예취구에서는 배수랑호구와 배수불랑구에서 총 목장수량에 대하여 각각 24%와 35%의 고사물량이 발생하였다. 3. 잡초발생은 1회, 2회예취시에는 거의 없었으나 3회 예취시부터 다량발생하였는데 산파구가 조파구에 비하여 높았고 ($P{\le}0.05$) 장마후 예취구가 장마전 예취구에 비하여 월등이 높았다. $P{\le}0.01$. 4. 목장의 피복율은 1회 예취율에는 거의 100%로 차이가 없었으나 2회 및 3회 예취후에는 장마전 예취구가 장마후 예취구에 비하여 매우 높은 수준을 보였으며 ($P{\le}0.01$) 조파는 산파에 비하여 높았으나 유의차는 없었다. 또한 각 처리구의 월동전식생 피복율은 장마전 예취구는 장마후 예취구에 비해 오차드그라스의 구성비율은 높았고 잡초 및 나지의 구성비율은 낮았다. 5. 본 실험결과로 미루어보아 오차드그라스채초지의 2회 예취는 장마전에 실시하고 조파를 함으로서 잡초발생을 크게 줄일 수 있을 것으로 생각된다.

• 한국토양비료학회지
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• 제39권2호
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• pp.102-108
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• 2006

비닐피복작물 재배시 시비효율 증대 및 생력시비기술 확립을 목적으로 토중시비기를 개발하였고 2000년 부터 2001년까지 2년 동안 이를 이용하여 양파를 재배한 후 토양개량, 양분이용률 및 수량성에 미치는 영향을 평가하였으며 그 결과는 다음과 같다. 시험 전 토양보다 모든 처리에서 치환성칼륨 함량은 증가되었으나 유효인산 함량은 감소되었다. 생육시기별 토양 중 질산태질소 함량은 모든 처리에서 생육초기에 가장 높았으며 특히 관행시비에 비하여 토중시비에서 $30-60mg\;kg^{-1}$ 높았고 3회 추비에서 생육후기까지 높게 발현되었다. 양파의 생장속도는 토중시비에서 높았고 생육중기 이후 차이가 크게 나타났으나 토중시비 추비횟수 사이에는 유의성이 없었다. 시비질소 흡수량은 관행시비($78kg\;ha^{-1}$)에 비하여 토중시비에서 59-69% 많았고 질소이용률은 추비 2회>추비 1회>추비 3회 순으로 18-20% 높았다. 시비칼리 흡수량은 관생시비($63kg\;ha^{-1}$)에 비하여 토중시비에서 52-71% 많았으며 칼리이용률은 13-17% 높았다. 시비방법별 시비질소 잔존량은 관행시비에 비해 토중시비에서 8-14% 많았고 시비질소 손실량은 관행($154kg\;ha^{-1}$)에 비해 토중시비에서 26-34% 적은 반면에 시비칼리 잔존량은 13-18% 많았고 시비칼리 손실량은 29-31% 적었다. 양파 생육 및 수량은 토중시비에서 엽초경과 구경이 굵고 구중이 무거워 관행시비($45.91Mg\;ha^{-1}$) 대비 7-13% 증수되었으며 질소시비효율이 22-42% 증대되었다.

• 한국작물학회지
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• 제14권
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• pp.91-96
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• 1973

우리나라 대두의 단위면적당 생산량은 제외국에 비해 낮은 편이며 그 원인은 여러 가지로 생각할 수 있으나 단시일내에 기존품종으로서 생산량을 높이는데 대두 초형에 따르는 재식방법의 개선이 중요하다고 여겨져 중부지방에서의 밀식적응대두형과 밀식정도의 구명을 위해 본 시험이 수행되었다. 본 시험에서는 모형과 각종 형질이 서로 상이한 품종인 장단백목, 충북백, Clark 등 3개 품종이 공시되었으며 휴폭을 세구로 그리고 주간거리를 세세구로 한 3반복으로서 시험하였다. 주당 분지수와 협수는 밀식에 따라 감소되었으나 동일한 밀도에서는 Clark에서 보다 충북백과 장단백목에서 더 많은 분지수를 가지고 있었으며, 협수에 관해서는 휴폭과 주간거리에 유의한 수준의 상호작용이 있었다. 절수는 품종간에 차이가 현저하였으며 휴폭에 의해서는 전혀 변화가 없었으며 주간거리가 커짐에 따라 Clark에서 약간 증가하였다. 간장도 주간거리에 관해서만 유의차가 현저하였으나 절수의 증가와는 관계없이 도장에 기인하였다. 도복성에는 Clark가 가장 강했으며 이는 이 품종 주경의 탄력성 때문인 것으로 여겨졌다. 밀식조건하에서는 다지성이고 광엽성인 재래품종들보다 절수가 많고 초장이 큰 도입품종 Clark가 공시된 3개 품종중 가장 수량이 많았으며 밀식재배용으로의 가장 알맞은 초형임이 명확하였고 파종은 재래식 점파보다는 조파로 밀식함이 노력이 절약되고 단위면적당 수량도 현저히 증가될 것이다.

• Structural Engineering and Mechanics
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• 제77권1호
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• pp.103-114
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• 2021

Ultra high strength concrete (UHSC) originally proposed by Richards and Cheyrezy (1995) composed of cement, silica fume, quartz sand, quartz powder, steel fibers, superplasticizer etc. Later, other ingredients such as fly ash, GGBS, metakaoline, copper slag, fine aggregate of different sizes have been added to original UHSC. In the present investigation, the combined effect of coarse aggregate (6mm - 10mm) and steel fibers (0.50%, 1.0% and 1.5%) has been studied on UHSC mixes to evaluate mechanical and fracture properties. Compressive strength, split tensile strength and modulus of elasticity were determined for the three UHSC mixes. Size dependent fracture energy was evaluated by using RILEM work of fracture and size independent fracture energy was evaluated by using (i) RILEM work of fracture with tail correction to load - deflection plot (ii) boundary effect method. The constitutive relationship between the residual stress carrying capacity (σ) and the corresponding crack opening (w) has been constructed in an inverse manner based on the concept of a non-linear hinge from the load-crack mouth opening plots of notched three-point bend beams. It was found that (i) the size independent fracture energy obtained by using above two approaches yielded similar value and (ii) tensile stress increases with the increase of % of fibers. These two fracture properties will be very much useful for the analysis of cracked concrete structural components.

• Asian-Australasian Journal of Animal Sciences
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• 제13권7호
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• pp.929-934
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• 2000

Optimum stand density of alfalfa (Medicago sativa L.) varies with locations and climates. Stand density is one of the factors that determines herbage yield, forage quality and persistence of alfalfa. As establishment costs increase, the question arises whether present population densities are optimum for obtaining maximum herbage yield and forage quality. The objectives of this study were: 1) to determine the optimum plant density for highest herbage yield and forage quality for the dehydrated alfalfa industry under Edmontons climatic conditions in Alberta, Canada; 2) to compare herbage yield and forage quality of the cultivars 'Algonquin' and 'Vernal' grown at a range of stand densities. Alfalfa seedlings of both cultivars were either transplanted at spacings of 6, 10, 15 and 25 cm or direct seeded at the 4.5 cm plant spacings, providing population densities of 494, 278, 100, 45 and $16plants/m^2$. The experimental design was a randomized complete block with a split-plot arrangement having three replicates; the main plots consisted of two alfalfa cultivars Algonquin and Vernal, and the sub-plots were the five population densities. The cultivar Vernal had significantly higher annual yield than did the cultivar Algonquin. There was no significant effect of plant density on herbage yield. There was no difference in crude protein (CP) between the two cultivars. At the first cut, there was a significant quadratic effect of plant density on CP content and the greatest CP occurred at the 100 plants/m2 density. Crude protein was not affected by plant density at the second cut. Acid detergent fiber (ADF) and neutral detergent fiber (NDF) were not affected by plant density. The cultivar Algonquin usually had a lower ADF and NDF than cultivar Vernal. In conclusion, high population densities ($278plants/m^2$ or more) of alfalfa did not improve herbage yield and forage quality compared with low plant population densities ($100plants/m^2$ or less) of alfalfa.

• 한국초지조사료학회지
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• 제16권2호
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• pp.161-168
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• 1996

This experiment was canied out to determine the effect of cultivar, harvest date and drying method on the changes of moisture content and quality of spring harvest oat(Avena sativa L.) hay. Disign of the experiment was a spilt-split-plot arrangement with early and late cultivars as main plots, early and late harvest dates as sub-plots, and drying agent and tedding as sub-subplots in three replications. Moisture content of early harvest oat was higher than that of late harvest oat by 127.1% dry weight(DW) in 'Swan' and 39.8%DW in 'Foothill'. Moisture content difference between 'Foothill' and 'Swan' was 117.6%DW at early and 204.9%DW at late harvest dates, respectively. Cultivar effect on moisture content of cut oat was higher at late harvest date, but drying method effect was higher at early harvest. Total nitrogen content of early harvest was higher than that of late harvest by 0.70% and that of 'Foothill' was higher than that of 'Swon' by 0.86%. But no difference in total nitrogen content was found between the drying method. ADF and NDF contents were increased at late harvest by 29% and 1 I%, respectively(P<0.05). ADF and NDF contents of 'Swan' were higher than those of 'Foothill' by 2.8% and 4.5%, respectively. No difference in ADF and NDF contents was obtained by drying methods. RFV of early harvest oat hay was 95.1 and 103.8 for 'Swan' and 'Foothill' but late harvest 'Swan' and 'Foothill' showed 74.8 and 85.0, respectively.

• 아시안잔디학회지
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• 제1권1호
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• pp.18-29
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• 1987

This study was carried out to examine the effect of nitrogen application and clipping interval on the characteristics of several turf components of korean lawngrass for the basic data of lawn management. It was treated by Split plot design with three replications. The main plots were nitrogen levels with 0, 350, and 700kgN / ha, and the sub plots were clipping intervals with 10, 20, and 30 days The results obtained are summarized as follows ; 1. Increasing the rate of nitrogen fertilizer and frequent clipping increased tiller number of korean lawngrass and the maximum number of tillers obtained in October were recorded from 700kgN application and clipping treatment of 10 days interval. Meanwhile, treatment of 350kgN with 10 days clipping interval increased tillers much more than those of 700kgN with 20 and 30 days clipping intervals. 2. The average number of green leaves occurred during the growth period maximized by applying 700 kgN and clipping 10 days interval. 3. Increasing tiller numbers significantly decreased tops DM weight per tiller by clippng plants at interval of 10 and 20 days, irrespective of nitrogen applied, and with nil N, at the interval of 30 days. By applying 700kgN however, tops DM weight per tiller increased as the number of tillers increased consistently. 4. The highest tops DM weight was achieved from late August to early September by applying 350 and 700kgN. 5. During the growth period, nitrogen application increased unders(stolon+root) DM weight, and, at the same level of nitrogen applied, the increase in stolon DM weight enhanced by lengthening the clipping interval to 30 days. 6. Nitrogen efficiency to green leaves, stolon nodes and DM weight of root with high nitrogen was achieved as clipping interval was shortened.

• Journal of Animal Science and Technology
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• 제63권5호
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• pp.1098-1113
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• 2021

Maturation process of alfalfa (Medicago sativa L.) could be prevented by the reduction of lignin content in terms of conventional breeding or transgenic technology. Alfalfa could exhibit higher leaf/stem ratio, with a concern of yield loss. The objective of this study was to compare forage yield and nutritive value of low lignin alfalfa and two reference varieties subjecting to two harvest intervals and three seeding rates. The experimental design was a randomized complete block in a split-split plot arrangement with four replicates, where harvest intervals (28-day and 35-day) were assigned to whole plots, seeding rates were subplots, and varieties were sub-subplots. The weighted mean nutritive value was applied to two production years of 2016 and 2017. Hi-Gest 360 (low lignin alfalfa) provided similar yield potential and increased nutritive value compared to two reference varieties. Over a two-year production period, alfalfa harvested at every 28-day interval provided more economic returns than those at 35-day interval. For the seeding year and first production year, five cuts made by the 28-day interval produced more yield than four cuts by the 35-day interval. Due to limited rainfall in May 2017, a sharp drop of the first cutting overturned the advantage of the five-cut system. Shorter intervals between harvests generally increased crude protein (CP) concentrations. The differences of relative feed value (RFV) between two harvest intervals tended to be great during the first and second cuttings. Overall, harvest interval had a large effect on nutritive value and a more significant effect on alfalfa dry matter yield than variety selection. Seeding rate did not affect alfalfa yield and nutritive value.

• 한국초지조사료학회지
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• 제26권4호
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• pp.293-300
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• 2006

본 시험은 제주도내 발생하는 돈분액비의 활용도를 높이고 화학비료 사용 절감 및 대처하는 목적으로 수행되어졌다. 품종간의 건물수량은 수수${\times}$수단그라스가 $1,480.4kg/10a$로 가장 높았으며, 수수${\times}$수수교잡종이 1,444.9.5 kg/10a, 옥수수 1,054.6 kg/10a로 나타났다.(p<0.01). 처리별 건물수량은 미생물제제를 처리한 돈분액비가 1,562 kg/10a로 높게 나타났으며, 돈분액비 시용구는 1,410 kg/10a, 화학비료구 1,008 kg/10a로 나타났다(p<0.01). 토양성분은 시험 전 1.32 ppm이었던 Zn 함량이 시험 후 화학비료구, 돈분액비구, 미생물제제를 처리한 돈분액비구에서는 4.23, 4.12, 4.00 ppm으로 나타났으며, Cu 함량은 시험 전 0.59 ppm 시험 후에 토양에서는 화학비료구, 돈분액비구, 미생물제제를 처리한 돈분액비구에서는 각각 0.821, 0.854, 1.027 ppm으로 높아졌다. 이 시험의 결과로 미생물제제를 처리한 돈분액비가 화학비료구나 일반돈분액비에 비해 비료성분이 떨어지지 않으며 관수효과까지 있어 사료작물에 적합한 비료자원이라 할 수 있겠다.

• 한국초지조사료학회지
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• 제11권2호
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• pp.108-115
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• 1991

A field experiment was conducted to evaluate the effects of cattle compost application on the change of soil physical properties and their relationship to yield performance of selected main forage crops. Maize(CV. Suweon 19) and sorghum hybrids(CV. Pioneer 9'31) as a summer crops and winter rye were grown on newly reclaimed red yellow soils(Fine loamy, Typic Hapludults) under different application rate of cattle compost associated with chemical NPK fertilization, from Oct. 1986 to Sept. 1989. Experimental field was laid down as a split plots design with four replications. The results obtained are summarized as follows: 1. Cattle compost application reclaimed soil physical propeties, such as formation of granular structure and water holding capacity, and it result in a great increase of plant growth and the rate of dry matter accumulation. 2. While cattle compost treatment reduced the portion of soild phase of the three phase constituents of soils, it increased the portion of air phase and liquid phase comparatively. 3. Organic matter, N, P, K, and mineral content in soil were markedly increased in the plot treated with compost. 4. Cattle compost application increased fodder production both in maize-rye and sorghum hybrids-rye cultivation. Annual dry matter yield of maize-rye cropping was 2183(NI'K only), 2425(NPK+compvst 3000 kg) and 2800kg/lOa(NPK + compost 6000kg/10a).