• 한국초지조사료학회지
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• 제7권1호
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• pp.8-17
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• 1987

Four foreign pasture cultivars such as Lotus corniculatus cv. Maitland, Trifolium pratense cv. Deben, Lolium perenne cv. $S_{23}$ and .Dactylis glomerata cv. $S_{26}$ were tested with "Kwisan" series, a common upland soil in Southern part of Korea. The cultivars in single or mixture were grown in pot with two levels of light intensity, i.e. a full sun light condition and 50% interception. Dry matter yield of top and root and their seasonal changes, the number of tillers or branches per plant and finally competative effects of mixtures were evaluated by estimating the expected yield, relative yield totals and compensation index. The results are summarized as follows: 1. Maitland showed a significant decrease in dry matter yield in shade condition, but the number of branches of Maitland was higher than those of Deben. 2. Maitland showed higher dry matter yield than Deben during the mid-summer period, while $S_{23}$, showed higher dry matter yield than $S_{26}$ during early season. 3. Mixtures of $S_{23}$ and Maitland, and $S_{26}$ and Deben gave better response to grasses by increasing the number of tillers in shade condition. 4. Combinations of Lotus corniculatus cv. Maitland and Dactylis glomerata cv. $S_{26}$ and Trifolium pratense cv. Deben and Dactylis glomerata cv. $S_{26}$ gave higher relative yield totals and higher compensation index, which envisages that the pasture establishment rates can be enhanced when those mixtures were sown by the oversowing method in the upland soil where phosphate level is very low and infertile in general.n general.

• 한국초지조사료학회지
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• 제15권4호
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• pp.279-284
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• 1995

The competition relationship between orchardgrass(Docflis glomerutu L. cv; Potomac) and red clover (Trifnlium prurense L. cv; Kenland) was investigated under the pure and mixed swards. Each species were grown in intra- and interspecific competition in pots and fields for 2-years. Intra- and interspecific competition were evaluated by calculating traditional methods; expected yield, relative yield total(RYT), aggressivity and compensation index(CI), and shoot and root dry matter production in the orchadgrass(ffi) pure, red clover(RC) pure and orchardgrdss(W)-red clover(RC) mixed sward. The results obtained were summarized as follows: Compared to OG and RC pure swards, the shoot and root dry maaer(DM) yield of OG-RC mixed sward were higher and more deeply rooted under the soil than those of OG and RC pure sward. Also, the number of tillen per plant of OG in the OG-RC mixed sward was less than that of OG pure sward, but that of RC in the OGRC mixed sward was more than that of RC pure sward. OG-RC mixed sward were evaluated as a productive sward type compared to OG and RC pure swards in that actual yield was higher than expect yield and that relative yield total(RYT), and compensation index(C1) were high. As mentioned above, compared to intraspecific competition as a OG and RC pure sward, interspecific competition as a OG-RC mixed sward was evaluated to productive type under the ffi and RC species utilization

• 한국초지조사료학회지
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• 제26권2호
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• pp.105-112
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• 2006

본 시험은 페레니얼라이그라스 위주 초지에서 목초 및 잡초의 건물중의 분포와 기능 및 목초와 잡초간 경합에 의한 상호작용을 조사하였다. 페레니얼라이그라스 위주 초지를 조파조성 및 조파 조성후 보파 관리하여 연 3회 예취와 방목이용하고 이 초지에서 발생량이 많은 잡초인 냉이, 바랭이와 피에 대하여 조파 및 보파한 채초지와 방목지에서 목초와 각 잡초간 상호작용을 측정하였다. 목초와 잡초간 상호작용의 측정을 위해 기대수량(expected yield : P), 상대지수(relative yield total : RYT), 보상지수(compensation index: CI) 및 형태지수 (morphological index: MI) 등 지수(Index)를 도입하였다. 도입된 이들 지수의 측정은 봄, 여름 및 가을의 각 예취 직전에 이루어졌는데 측정된 각 지수는 각 처리구별 예취 시기별 및 잡초 종류 따른 차이와 변화가 인정되었다. 기대수량의 경우 가을 이용시기에 보파에 의해 약간 증가하였으나 상대수량에 있어 0.17에서 0.41 범위에 있어 크게 개선되지는 않는 것으로 나타났다. 보상지수는 -0.3에서 -0.6 범위로 모두 과소보상(+, --)으로 나타나 잡초에 의한 수량감소가 크게 이루어진 것으로 나타났다. 페레니얼라이그라스 위주 초지에서 보상지수를 감소시키는 주요 잡초인 바랭이, 피의 경우 방목이용에 따른 페레니얼 위주 초지의 개선효과 보다 조파 및 조파 후 보파관리에 의한 개선효과는 크지 않았다.

• 한국산림과학회지
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• 제106권4호
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• pp.457-464
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• 2017

본 연구에서는 소나무 임분밀도관리도를 이용하여 소나무 임분의 건정성을 확보할 수 있는 효율적인 임분밀도 관리 기준을 마련하고 이로부터 실행가능한 임분의 생산목표를 예측하였다. 적정 임분 관리수준은 임내 세장목 비율에 대한 수량비수(Relative yield index: Ry)의 관계를 지수함수로부터 모형 추정을 하였으며, 추정 결과 모형 설명력은 0.424로 나타났다. 임내 세장목 비율은 특정 수량비수에 도달하면 급격히 증가하는 경향이 나타났고, 이 관계식을 근거로 하여 목표하는 적정 Ry 값 0.84를 구하였다. 적정 임분밀도 관리 기준인 Ry 0.84 값의 곡선과 중부지방소나무의 우세목 수고를 예측하여 지위지수별 생산목표를 설정하였다. 중부지방소나무 지위지수 10~16의 범위에서 벌기령을 60년으로 할 때 예측되는 수확본수는 ha당 425~1,311본으로 나타났다. 목표 흉고직경은 지위지수 16이상에서 30 cm 이상 중경재 생산이 가능하며, 지위 14와 12는 20 cm 이상 소경재 생산, 지위 10은 20 cm 미만 소경재 생산이 가능할 것으로 예측되었다.

• Asian-Australasian Journal of Animal Sciences
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• 제17권2호
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• pp.159-163
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• 2004

Data pertaining to first lactation records of 316 Murrah buffaloes, progeny of 47 sires, maintained at NDRI Farm for a period of 18 years were analysed to construct selection indices and to examine their robustness by changing the relative economic values of different economic traits. A total of 120 selection indices were constructed for three sets of relative economic values ( 40 for each set) considering different combinations of seven first lactation traits viz. age at first calving (AFC), first lactation 305 day or less milk yield (FLMY), first lactation length (FLL), first calving interval (FCI), milk yield per day of first lactation length (MY/FLL), milk yield per day of first calving interval (MY/FCI) and milk yield per day age at second calving (MY/ASC). The three sets of relative economic values were based on economic values of different traits, 1% standard deviation of different traits and regression of different traits on FLMY. The 'optimum' indices for the first two sets had five traits each namely AFC, FLMY, FLL, FCI and MY/ASC giving improvement in aggregate genotype of Rupees 269.11 and Rs. 174.88, respectively. The accuracy of selection from both indices was 70.79 and 69.39%, respectively. The 'best' selection index from the third set of data again had five traits (AFC, FLMY, FLL, FCI and MY/FLL) giving genetic gain of Rs. 124.16 and accuracy of selection of 71.81%. The critcal levels or break-even points for FLMY for varying levels of AFC and FCI estimated from the "optimum index" suggested the need of enhancement of present production level of the herd or reduction of AFC or FCI. It was concluded that economic values of various first lactation traits were the most appropriate to construct selection indices as compared to other criteria of assigning relative economic weights in Murrah buffaloes.

• Journal of Forest and Environmental Science
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• 제30권3호
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• pp.259-266
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• 2014

Stand Density Diagrams (SDD) are average stand-level models which graphically illustrate the relationship between yield, density and mortality throughout the various stages of forest development. These are useful tools for designing, displaying and evaluating alternative density regimes in even-aged forest ecosystems to achieve a desired future condition. This contribution presents an example of a SDD that has been constructed for teak forests of Karnataka in southern India. The relationship between stand density, dominant height, quadratic mean diameter, relative spacing and stand volume is represented in one graph. The relative spacing index was used to characterize the population density. Two equations were fitted simultaneously to the data collected from 27 sample plots measured annually for three years: one relates quadratic mean diameter with stand density and dominant height while the other relates total stand volume with quadratic mean diameter, stand density and dominant height.

• 한국작물학회지
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• 제45권1호
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• pp.1-5
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• 2000

Leaf area is critical for crop light interception, and thereby has a substantial influence on crop yield. This experiment was conducted to characterize the development of soybean [Glycine max (L.) Merr.] leaf area. Plastochron index and leaf relative growth rate of Jackson was contrasted with the PI416937, which also has demonstrated tolerance to drought. First, plastochron ratio (PR) and plastochron index (PI) were evaluated in greenhouse to compare the leaf growth rate between two genotypes under well-watered condition. There was reasonable constancy of PR between two genotypes. The PR means of Jackson and PI416937 were 0.41 and 0.44, respectively. A fairly smooth increase of PI during vegetative stage was observed. Second, the relative growth rates were graphed against leaf area, normalized with respect to final leaf area, under well-watered and water-deficit conditions. Leaf growth was sustained longer in well-watered condition than water-deficit condition and there was a sizable proportion of leaves which was ceased earlier their growth in water-deficit condition compared to well-watered condition. The leaf relative growth rate of Jackson until leaves had completed at 45% of their growth during water deficit period was higher than that of PI416937.

• 농업과학연구
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• 제48권1호
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• pp.45-57
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• 2021

This study aimed to determine the effects if ambient temperature (Ta), relative humidity (RH), and temperature-humidity index (THI) on milk production parameters such as milk yield, fat, protein, milk urea nitrogen (MUN), and lactose. A total of fifty (50) mid-lactating Korean Holstein cows (144 - 150 days postpartum) were randomly assigned to two groups in equal numbers (n = 25) according to the type of diet received: conventional feed, a mixture of 56: 44 ratio of roughage and concentrate mix, and organic feed containing 100% organic roughage. Temperature, RH, and THI were recorded daily and averaged monthly. Conventional group showed higher dry matter intake throughout the experiment and thus, showed higher total milk yield and milk composition such as milk fat, protein, and lactose content than organic milk. Milk of the conventional group showed higher polyunsaturated fatty acid concentration. Highest milk yield was observed in September (21.7℃, 82.4%RH) in conventional group (27.69 kg·day^-1) and in June (21.4℃, 72.9%RH) in organic group (14.31 kg·day^-1). In conventional group, milk yield was positively correlated with Ta and THI, and milk protein was negatively correlated with Ta, RH, and THI. In organic feeding, only the MUN among milk composition parameters showed a significant correlation where it showed a negative correlation with Ta, RH, and THI. Conventional feeding showed significantly higher milk yield, fat, protein, and lactose than organic feeding throughout the experiment, although, organic feeding showed to be less likely affected by Ta, RH, and THI than the conventional feeding.

• 한국작물학회지
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• 제50권1호
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• pp.5-10
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• 2005

This experiment was conducted to clarify the functions of supernodulating characters on seed yield determination through the comparison of agricultural traits of supernodulating soybean mutants, Sakukei4, SS2-2, and their parent cultivars, Enrei and Shinpaldalkong2. The plant dry weights of supernodulating mutants, Sakukei4 and SS2-2, were $52\%$ and $61\%$ of their wild type parents at full seed stage (R6). However, the relative growth rate (RGR) from the pod set stage (R3) to R6 of Sakukei4 was 0.022 g/g/day and that of SS2-2 was 0.016 g/g/day, which were higher than those of their parents. Nodule number and dry weight were increased in two supernodulating mutants by the R6 stage. The nitrogen concentrations of leaf, petiole and stem of Sakukei4 were higher than those of Enrei. SS2-2 showed higher nitrogen concentration in petiole than Shinpaldalkong2 had. The positive correlations were appeared between nodule dry weight, plant dry weight and pod number, in two supernodulating mutants during the period from R3 to R6 stage. Although all of the yield components and seed yield were lower in two supernodulating mutants than their parents at the stage of full maturity (R8), the harvest index was higher in supernodulating mutants. The increasing rates of pod number to stem dry weight in two supernodulating mutants showed the higher than those of two their parents at R8 stage. In conclusion, the relative growth rates during the early to the middle reproductive growth period were higher in supernodulating mutants than the wild types. This could be resulted in an increase in pod number. The increase of relative growth rate was the result of the successive supplement of nitrogen source from biological nitrogen fixation (BNF) of nodules during the middle reproductive growth period in supernodulating mutants.

• 한국토양비료학회지
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• 제51권2호
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• pp.111-118
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• 2018

A field experiment was conducted to investigate the effect of long-term (21-year) fertilizer and compost treatments on the yield of red pepper and chemical properties in top-dong, Suwon. Six treatments were chosen for this work: No fertilization (No fert.), NPK fertilizers (NPK), NPK and compost (NPK+Compost), NP and compost (NP+Compost), NK and compost (NK+Compost), PK and compost (PK+Compost). The yield of red pepper for 21 years indicated the significant differences among the No fertilization, the PK+Compost, and other treatments. The relative yield index was 13% and 59% respectively, for the No fertilization and the PK+Compost if the average yield of red pepper for the NPK regards $20,048kg\;ha^{-1}$ as the yield index with 100%. Soil organic matter at the compost applied treatments significantly increased compared with the No fert. and the NPK. The average increase rates of soil organic matter by applying the compost ranged from 0.69 to $0.73g\;kg^{-1}\;yr^{-1}$. Available phosphate content in soil appeared the significant increase all treatments excluding the No fert. It is estimated that the available phosphate in soil was increased by $7.0mg\;kg^{-1}\;yr^{-1}$ by applying compost and $14.2mg\;kg^{-1}\;yr^{-1}$ by applying P fertilizer. Application of K fertilizer or the compost alone, the NPK, the NP+Compost, continuously caused soil K depletion whereas K fertilization plus the compost maintained at a constant level of exchangeable K. The results indicated that the addition of compost to NPK fertilizer is recommended for the maximum stable yield for red pepper and enhancement of organic matter though it is also needed for adjusting of P and K fertilization.