• Journal of the korean society of oceanography
• /
• 제39권3호
• /
• pp.186-196
• /
• 2004

Since seagrasses are highly productive and provide a source of organic carbon for a wide variety of marine organisms in coastal and estuarine ecosystem, accurate assessment of seagrass production is critical to understand the functions and values of seagrasses in these ecosystems. Zieman's leaf marking technique has been mostly used to estimate seagrass leaf production rates. However, inherent problems on the traditional leaf marking technique have been discussed by the several researchers, and these problems can cause underestimation of seagrass production. To develop an accurate and reliable assessing method for seagrass production, production rates of eelgrass, Zostera marina in three bay systems on the south coast of the Korean peninsula were estimated using the conventional leaf marking technique and the plastochrone method. The plastochrone method has been recently suggested as an effective method for reliable assessments of seagrass production. In the present study, leaf production rates estimated by the plastochrone method were significantly higher than the rates derived from the traditional leaf marking technique. Annual eelgrass leaf production assessed using the leaf marking technique was about 65 to 89% of the estimated production using the plastochrone method. The differences in annual productions between assessment techniques imply that the conventional leaf marking technique significantly underestimated eelgrass leaf production. Total eelgrass productions estimated using the plastochrone method in the present study sites were about 600 to 806 g DW $m^{-2} y^{-l}$, and below-ground production accounted for about 20 to 23% of the total production. The plastochrone method was suggested to be an effective and accurate assessing method for eelgrass production.

• 농업과학연구
• /
• 제31권2호
• /
• pp.149-160
• /
• 2004

This study had carried out an analysis of leaf tobacco production cost by cost items, growing stages, and farm sizes per 10a to provide the basic data for determination of the purchasing price of leaf tobacco by KT&G. Considering the survey results of 12 tobacco farm households, the composition rates of production cost by items revealed as 7-10% for land service, 5-22% for depreciation, 13-25% for material costs, 50-65% for labour cost respectively. The production cost of leaf tobacco by growing stages were shown as 15.3% in nursery bed period, 32.3% in main growing period in field, 30.8% in harvesting period and 21.6% in packing period. The magnitude of wage expenditure was appeared as harvesting stage, packing stage, growing stage on main field and nursery bed stage in order. The amount of material costs were revealed as the growing stage in main field, harvesting stage, nursery bed stage and packing stage respectively. The production costs of leaf tobacco per 10a by farm sizes were shown as 1,615,879won for small farm, 1,446,896won for medium farm and 1,454,408won for large farm respectively. The production cost of leaf tobacco had shown decreasing tendency according to increasing farm sizes. To promote the international market competitiveness of leaf tobacco producing farms, labour saving production technologies and cost effective farm size to decrease tobacco production cost should be developed.

• Plant Resources
• /
• 제6권3호
• /
• pp.211-214
• /
• 2003

This study was conducted to produce effectively more leaves of Angelica acutiloba through year-round production system by using various mulching materials and polyethylene(PE) tunnel. Soil temperature by covering treatment was higher in PE mulching and PE tunnel than in rice straw mulching, especially showing the highest temperature in PE tunnel from April through May. Water content of soil was higher in PE mulching than in non-mulching. Leaf production of Angelica acutiloba through year-round production showed the highest in PE tunnel and root production in PE mulching. These results suggest that leaf production of Angelica acutiloba can be maximized through PE tunnel cultivation system.

• Plant Resources
• /
• 제8권1호
• /
• pp.27-31
• /
• 2005

This study was conducted to produce effectively more leaves of Angelica acutiloba through year-round production system by using various mulching materials. Soil temperature by covering treatment was the highest in P.E.(Polyethylene Film) mulching and followed by rice straw mulching, especially showing highest temperature in Tr. PE(Transparent Polyethylene Film) from April through May. Water content of soil was higher in P.E. mulching than in non-mulching. Leaf and stem production of Angelica acutiloba through year-round production showed the highest in PE mulching also root production of Angelica acutiloba showed the highest in P.E. mulching. These results suggest that leaf and stem production of Angelica acutiloba can be maximized through P.E. mulching cultivation system.

• Journal of Ecology and Environment
• /
• 제33권3호
• /
• pp.253-260
• /
• 2010

It has been well established that leaf longevity is linked to the carbon economy of plants. We used this relationship to predict leaf lifetime carbon gains from leaf lifespan, and estimated the gross primary production (GPP) of a young deciduous forest of Japanese beech (Fagus crenata) located in central Japan. The light-saturated photosynthetic rates of the leaves were measured repeatedly during the growing season. We used the leaf lifespan to calculate the conversion coefficient from the light-saturated photosynthetic rate into the realized leaf lifetime carbon gain under field conditions. The leaf turnover rate was estimated using litter traps. GPP was estimated as the product of lifetime carbon gain per unit of leaf mass, and the annual leaf turnover rate. The GPP of the forest in 2007 was estimated to be $1.2{\times}10^3gCm^{-2}y^{-1}$, which was within the range of previously reported GPP values of beech forests in Japan, and was close to the GPP of a European beech forest, as estimated by eddy flux measurements.

• Asian-Australasian Journal of Animal Sciences
• /
• 제5권2호
• /
• pp.257-259
• /
• 1992

Three tropical legumes, very different in growth form, but believed to be of potential value for animal production were evaluated by substituting the leaf meal made from each for lucerne at the level used in a standard diet for growing rabbits (50%). Each leaf meal had a nitrogen content of close to 3.5% and contributed about 60% of the crude protein in the diet. Albizia lebbeck and Clitoria ternatea showed no evidence of toxic or antinutrient effects. The protein digestibility of the complete diets were 66 and 61% respectively, implying a protein digestibility of the leaf of at least 50%. Both species would be suitable for practical production diets for rabbits and should be excellent for ruminants. In contrast, the diet containing Desmanthus virgatus had a protein digestibility of only 40%, implying that only about 15% of the leaf protein was available. The leaves showed marked non-enzymic browning on drying. When dried this species is clearly unsuitable as a feed for rabbits and possibly also for ruminants. However, it may well be valuable as fresh forage.

• 한국산학기술학회논문지
• /
• 제22권1호
• /
• pp.313-320
• /
• 2021

본 연구는 경남 밀양 깻잎 농업의 수급 및 가격 모형을 개발하고 정책 실험을 통해 밀양 깻잎 생산 농가의 총 소득을 극대화하는 적정 생산 규모를 전망한다. 분석 자료는 밀양 깻잎 농업의 총 소득과 관련된 22개년 시계열 자료(1996~2017년)가 이용되었다. 분석 방법은 수요 함수와 평균 비용 함수 추정을 통하여 적정 생산량과 가격을 산출하고 이를 통해 적정 소득을 도출하였다. 또한, 시나리오 분석을 통하여 2030년까지 예상되는 밀양 깻잎 최적 생산량과 이에 해당하는 판매 가격, 총 수입, 총 비용, 총 소득을 전망하였다. 밀양 깻잎 생산 농가 전체를 대상으로 총 소득을 극대화하기 위해서는 2017년에 7천 톤 규모인 밀양 깻잎 생산량을 2030년까지 10~12.5천 톤으로 증가시킬 필요가 있다. 이 경우 밀양 깻잎 농업에 귀속되는 총 소득은 133~213억 원 수준으로 전망된다. 앞으로 밀양 깻잎 생산자 단체는 본 연구에서 제시한 적정 생산 규모를 유지하여 농가에게 귀속하는 총 소득을 증대시키도록 노력해야 할 것이다.

• Journal of Ecology and Environment
• /
• 제33권1호
• /
• pp.59-65
• /
• 2010

Because seagrass production significantly contributes to the biodiversity and production of coastal and estuarine ecosystems, accurate estimation of seagrass productivity is a critical step toward understanding the ecological roles of seagrass in these ecosystems. To develop an accurate and effective method of measuring seagrass productivity, we estimated leaf productivity of eelgrass (Zostera marina) on the southern coast of Korea using three methods, the conventional leaf marking method, the elongation-mass method (Short '87 method), and the plastochrone method. In each season, shoots were pierced through the bundle sheath using a hypodermic needle and were collected after 2-4 weeks had elapsed to estimate their productivity. The leaf elongation and the leaf plastochrone intervals varied significantly among seasons. On an annual basis, the conventional leaf marking method showed the lowest leaf productivity estimates compared to the elongation-mass method and the plastochrone method, suggesting that the conventional leaf marking method underestimated leaf productivity as it ignored leaf maturation processes and new leaf growth within the sheath. Since the elongation-mass method considered leaf maturation processes, this method produced higher leaf productivity estimates than the conventional leaf marking method. On an annual basis, the plastochrone method produced the highest leaf productivity estimates. Below-ground productivity, which can be easily estimated using the plastochrone method, ranged between 3.29 and 5.73 (mg dry weight $shoot^{-1}\;day^{-1}$) and accounted for about 17.8% to 30.3% of total productivity. Because of the high contributions of below-ground productivity to total seagrass production, we suggest that the plastochrone method is an effective and simple technique for assessing both above- and below-ground productivities.

• Plant Resources
• /
• 제8권2호
• /
• pp.167-170
• /
• 2005

This study was conducted to determine feasibility of production system of Perilla frutescens leaf-stem by fertilizing of Sta-Green in pots. Germination rate of Perilla frutescens seeds collected in 2002 was $7\%$, also germination rate of seeds collected in 2003 was $62\%$, while germination rate of seeds collected in 2004 was above $93\%$. Seed germination rate of Perilla frutescens collected in 2004 were higher than seed gathering in 2002. Especially, plant growth and yield of Perilla frutescens grown in pot(The pots was filled with soil mixtures of Sta-Green and Peat Moss mixed with 40:60 ratio.) was the highest. These results indicate that leaf and stem production of Perilla frutescens can be improved by fertilizing of Sta-Green in pots.

• 한국작물학회지
• /
• 제49권5호
• /
• pp.363-367
• /
• 2004

The deep irrigation of rice plants brings about some beneficial effects such as reduced tiller production which results in the formation of bigger panicles, prevention of chilling injury, reduced weed growth, etc. The present study was carried out to examine the involvement of ethylene in the suppression of tiller production due to deep water irrigation in rice (cv. Dongjinbyeo). The ethylene production was induced in leaf sheath within 24 hours after the deep water irrigation and has increased even until 30 days after the treatment, recording 4.5-fold increase as compared to the shallow-irrigated rice plants. In the deep water irrigated rice plants, ethylene was accumulated to a high concentration in the air space of submerged leaf sheath as the irrigated water deterred the diffusion of ethylene out of the leaf sheath and ethylene biosynthesis was accelerated by the deep irrigation as well. The ethylene concentration recorded 35-fold increase in the deep-irrigated rice plants for 35 days. The tiller production was reduced significantly by the deep irrigation with water, the tiller bud, especially tertiary tiller bud differentiation being suppressed by the deepwater irrigation treatment, whereas the rice plants deep-irrigated with solutions containing $10^{-5}$ M or $10^{-6}$ M silver thiosulfate (STS), an action inhibitor of ethylene, showed the same or even higher production of tillers than those irrigated shallowly with water. This implies that the ethylene is closely linked with the suppression of tiller production due to deep water irrigation. In conclusion, ethylene, which was induced by hypoxic stress and accumulated in the leaf sheath due to submergence, played a key role in suppressing the tiller production of the deepwater irrigated rice.