• 한국환경농학회지
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• 제37권3호
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• pp.172-178
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• 2018

BACKGROUND: Composted animal manure applied to the arable soil for improving soil quality and enhancing crop productivity causes greenhouse gas emissions such as nitrous oxide ($N_2O$) by processes of nitrification and denitrification. However, little studies have been conducted on determining effect of application ratio of composted animal manure on $N_2O$ emission rate and its annual emission pattern from upland soil in South Korea. Therefore, this study was conducted to determine $N_2O$ emission rate and its annual emission pattern from upland soil supporting for sweet potato. METHODS AND RESULTS: Composted animal manure was applied at the ratio of 0, 10, and 20 Mg/ha to an upland soil supporting for sweet potato (Ipomoea batatas). Nitrous oxide emission was examined during growing season and non-growing season from May 2016 through May 2017. Daily $N_2O$ fluxes showed peaks right after applications of composted animal manure and inorganic nitrogen fertilizer. Precipitation and soil water content affected daily $N_2O$ flux during non-growing season. Especially, $N_2O$ flux was strongly associated with water filled pore space (WFPS). We assumed that the majority of $N_2O$ measured during growing season of sweet potato was produced from nitrification and subsequent denitrification. Annual cumulative $N_2O$ emission rate significantly increased with increasing application ratio of composted animal manure. It increased to 12.0 kg/ha/yr from 8.73 kg/ha/yr at control with 10 Mg/ha of composted animal manure and to 14.0 kg/ha/yr of $N_2O$ emission with 20 Mg/ha of the manure. CONCLUSION: To reduce $N_2O$ emission from arable soil, further research on developing management strategy associated with use of the composted animal manure and soil moisture is needed.

• 한국농공학회논문집
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• 제51권5호
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• pp.25-34
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• 2009

The objective of this study is to evaluate the future potential climate and vegetation canopy change impact on a dam watershed hydrology. A $6,661.5\;km^2$ dam watershed, the part of Han-river basin which has the watershed outlet at Chungju dam was selected. The SWAT model was calibrated and verified using 9 year and another 7 year daily dam inflow data. The Nash-Sutcliffe model efficiency ranged from 0.43 to 0.91. The Canadian Centre for Climate Modelling and Analysis (CCCma) Coupled Global Climate Model3 (CGCM3) data based on Intergovernmental Panel on Climate Change (IPCC) SRES (Special Report Emission Scenarios) B1 scenario was adopted for future climate condition and the data were downscaled by artificial neural network method. The future vegetation canopy condition was predicted by using nonlinear regression between monthly LAI (Leaf Area Index) of each land cover from MODIS satellite image and monthly mean temperature was accomplished. The future watershed mean temperatures of 2100 increased by $2.0^{\circ}C$, and the precipitation increased by 20.4 % based on 2001 data. The vegetation canopy prediction results showed that the 2100 year LAI of deciduous, evergreen and mixed on April increased 57.1 %, 15.5 %, and 62.5% respectively. The 2100 evapotranspiration, dam inflow, soil moisture content and groundwater recharge increased 10.2 %, 38.1 %, 16.6 %, and 118.9 % respectively. The consideration of future vegetation canopy affected up to 3.0%, 1.3%, 4.2%, and 3.6% respectively for each component.

• 화훼연구
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• 제16권4호
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• pp.255-259
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• 2008

준고냉지에서 안개초 'Bristol Fairy'를 실험재료로 이랑높이를 10, 20, 30, 40 cm로 하여 토양 물리성, 생육 및 개화특성 등을 조사하였다. 주간 지온, 토양 수분함량, 토양 경도, 용적밀도 및 고상률은 이랑이 높을수록 낮고, 공극률은 약간 높아지는 경향이었다. 여름과 가을 절화작형에서 30 cm, 40 cm 이랑에서 개화는 약간 지연되었으나, 뿌리활력, 화수폭과 절화량은 우수하였다. 여름을 경과하면서 발생한 고사주율 및 로젯트 발생률, 비원추화서률 등 생리장해 발생도 낮아지는 경향이었다.

• 아시안잔디학회지
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• 제23권2호
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• pp.229-240
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• 2009

여름철 고온 다습한 우리나라 기온에서 토양 온도와 수분은 잔디의 생리학적 변화를 초래하며, 특히 한지형 잔디생육은 우리나라 여름철 기후의 특이성에 많은 영향을 받는다. 본 실험은 크리핑 벤트그래스(Agrostispalustris Huds.)를 이용하여 고온의 조건에서 각기 다른 토양 수분함량 조건에서의 한지형 잔디생육을 관찰하였다. 구체적인 실험 방법으로는 수분함량과 온도에 따른 bentgrass의 생육 및 생리적 스트레스 반응을 평가하였다. 모의 USGA(United State of Golf Association) 그린 조건에서의 토양 온도 및 열 특성 실험 결과 수분이 거의 없는 건조 상태에서의 토양 온도는 $34^{\circ}C$로 발열 했을 때 토양 표면 온도가 $80^{\circ}C$까지 올라가는 것을 알 수 있었다. 반면, 과수분 조건에서 $34^{\circ}C$ 발열을 했을 때에는 건조 조건에 비해 상대적으로 $10^{\circ}C$가 낮은 것을 알 수 있었다. 실험 포장에서의 온도와 수분에 따른 열 특성 변화는 관수시기와 무관하게 처리구 모두에서 관수 후에 열전도도(thermal conductivity), 열 확산성(thermal diffusivity), 및 토양 온도가 증가하였다. 이는 수분이 공기에 비해 상대적으로 높은 열전도도를 갖기 때문으로 사료된다. 또한, 본 실험에서 관수 초기에는 과수분 조건에 비해 수분 결핍 조건에서 토양 온도의 증가를 보였으며, 시간이 지남에 따라 과수분 조건에서 더 높은 토양 온도의 증가를 확인하였다. 즉, 토양 온도는 과수분 조건에서 열전도에 의해 높아져 잔디의 생육에 영향을 미친다. 이는 잔디 표면부 온도가 높은 시각대의 과도한 관수는 여름철 잔디의 생육에 부정적 영향을 미치며, 소나기 등에 의한 일시 침수 시 지반배수의 불량은 잔디 생육에 치명적인 요인이 될 수 있다는 것을 의미한다.

• 한국균학회지
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• 제3권1호
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• pp.1-19
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• 1975

Since the importance of casing in fruit body formation of Agaricus bisporus has been emphasized, physico-chemical characteristics of casing materials were discussed by many workers and a mixture of peat and mineral soil as proper casing material has been adopted in many of mushroom growing countries. Because of limited resources of peat in Korea, it is necessary to find practical performance and substitutional materials for casing. The effect of casing on mycelial growth and mushroom yield of A. bisporus varied with materials, its combination and practices etc. The experiments to be discussed in this paper are concerned with pH and Ca of casing material which influence A bisporus, and changes of physico-chemical characteristics with mixing ratio of casing materials and its effect on A. bisporus. The optimum range of moisture content of each material, management of watering and application of physico-chemical characteristics casing materials was also investigated and re-use of weathered spent compost for casing material was described. 1. The effect of calcium on mycelial growth of A. bisporus at various pH in Halbschalentest showed different results with calcium sources. Best results were obtained around neutrality and fresh weight of fruit bodies grown in the range of pH 7 to 8 was highest among the tested levels. 2. Available moisture, pore space, organic matter, cation exchangeable capacity and exchangeable cation was increased by an increase of mixing ratio of peat in casing materials, while an adverse effect was obtained by addition of sand. 3. Mycelial growth on clay loam was more rapid at a lower bulk density of 0.75g/cc and at 20% moisture content on a dry weight basis at the same bulk density. 4. Mixing ratio of casing materials, 60 to 80 per cent by volume of peat mixed with 20 to 40 per cent of clay loam produced the highest yield of fresh fruit bodies and sand the lowest. However, per cent of open cap was highest in peat and lowest in sand. 5. Days required for fruit body initiation was shortened in mixtures of peat and clay loam by one to three days compared with other materials and the formation of flushes was clear. 6. The effect of some physico-chemical characteristics of casing materials on the fresh weight of fruit bodies were estimated by a multiple regression equation; Y=-923.86+$8.18X_1+8.04X_2+7.90X_3+0.12X_4+2.03X_5-0.82X_6-0.54X_7$ where $X_1,X_2,X_3,X_4,X_5,X_6,X_7$ are sand, silt, clay, available moistuer, porosity, organic matter and exchangeable cation respectively. The productivity of certain casing material could be predicted from this equation. 7. Fresh weight of fruit bodies was positively correlated with porosity exchangeable cation, organic matter, available moisture, silt and clay of materials; while sand was negatively correlated. On the contrary, sand was the unique factor reducing per cent of open cap. 8. Distribution of three phases of high productive casing material was concentrated in the range of 10 to 30 per cent solids, 15 to 30 per cent liquids, and 50 to 60 per cent in air volume. 9. Fresh weight of fruit bodies from peat was not affected with heavy watering but in clay loam and sandy loam severe crop losses occurred. Fresh weight of individual fruit was increased and open caps were decreased with heavy watering but light watering resulted in adverse effects: its effect was especially great in peat. 10. Optimum range of moisture content by weight on a dry basis was different with each casing material. To maintain optimum moisture content concerned with yield of fruit bodies and open cap, sandy loam and peat mixtures required daily watering of 0.6, 0.6 to 1. 2 and 1.2 to 2.4 liters per $3.3m^2$ of bed area, respectively. 11. Maximum yield of fruit body was recorded in the range of pF 2. 0 to 2. 5 of casing materials if organic matter content was below 4.2 per cent and in pF 1. 3 to 1.8 if above 7.1%. 12. pF curve of a certain casing material could be draws from moisture content at various pF values by multiple regression equations provided texture, organic matter and calcium of the casing material are given. Optimum moisture range of the casing materials also could be estimated by the equation. 13. It was possible to improve the phyico-chemical characteristics of clay loam and sandy loam by addition of weathered spent compost although the effect was less than in the case of peat. Fresh weight of fruit bodies wsa increased by addition of weathered spent compost but its effect was not as remarkable as peat. Accordingly, further studies will be required.

• 한국토양비료학회지
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• 제46권6호
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• pp.409-416
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• 2013

Millet and sorghum are major dryland cereal crops, however their growth and productivity is limited by soil water stress with varying intensity. The major objective of this study was to evaluate water stress of millet and sorghum yield under drainage classes of poorly drained soil and to test the effect of the installed pipe drainage in poorly drained paddy soil to minimize crop stress. The research was carried out in poorly drained paddy fields located at alluvial slopping area resulting in non-uniform water content distribution by the inflow of ground water from the upper part of the field. Stress Day Index (SDI) was determined from a stress day factor (SD) and a crop susceptibility factor (CS). SD is a degree of measurement by calculating the daily sum of excess water in the profile above 30cm soil depth ($SEW_{30}$). CS depends on a given excess water on crop stage. The results showed that sum of excess water day ($SWD_{30}$) used to represent the moisture stress index was lower on somewhat poorly drained soil compared with poorly drained soil on 117 days. CS values for sorghum were 57% on $3^{rd}$ leaf stage, 44% on $5^{th}$ leaf stage, 37% on panicle initiation, 23% on boot stage, and 16% on soft dough stage. For proso millet CS values were 84% on $3^{rd}$ leaf stage, 70% on $5^{th}$ leaf Stage, 65% on panicle initiation, 53% on boot stage, and 28% on soft dough stage. And for foxtail millet the values were 73% on $3^{rd}$ leaf stage, 61% on $5^{th}$ leaf stage, 50% on panicle initiation, 29% on boot stage, and 15% on soft dough stage. SDI of sorghum and millet was more susceptible to excess soil water during panicle initation stage more poorly drained soil than somewhat poorly drained soil. Grain yield was reduced especially in proso millet and Foxtail millet compared to Sorghum.

• 한국농공학회논문집
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• 제66권4호
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• pp.17-26
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• 2024

This study aimed to design and build a web-based decision support system for wheat cultivation management. The system is designed to collect and measure the weather environment at the growth stage on a daily basis and predict the soil moisture content. Based on this, APSIM, one of the process-based crop models, was used to predict the potential yield of wheat cultivation in real time by making decisions at each stage. The decision-making system for wheat crop management was designed to provide information through a web-based dashboard in consideration of user convenience and to comprehensively evaluate wheat yield potential according to past, present, and future weather conditions. Based on the APSIM model, the system estimates the current yield using past and present weather data and predicts future weather using the past 40 years of weather data to estimate the potential yield at harvest. This system is expected to be developed into a decision support system for farmers to prescribe irrigation and fertilizer in order to increase domestic wheat production and quality by enhancing the yield estimation model by adding influence factors that can contribute to improving wheat yield.

• 한국농림기상학회지
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• 제11권2호
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• pp.52-60
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• 2009

본 실험은 사과원 토양으로부터의 $CO_2$방출량을 정량적으로 파악하고, 토양호흡과 환경인자와의 관계를 알아보기 위해 수행되었다, 실험은 경기도 수원 국립 원예특작과학원 내의 사과 '후지' 과수원에서 2007년 4월 23일$\sim$2008년 3월 31일까지 실시하였다. 자체 제작한 자동 토양호흡 측정장치(밀폐법)를 이용하여 밀폐법에 근거하여 사과원의 토양 호흡을 지속적으로 측정 하였다. 토양 호흡속도의 일변화는 일출 이후의 온도 상승과 함께 아침 7시경부터 증가하여, 온도가 가장 높은 $14{\sim}15$시경에 최대값($399.4{\sim}450.9mg$ $CO_2$ $m^2d^{-1}$)을 나타내었으며 이후 온도의 하강과 함께 감소하였다. 토양 호흡속도는 $0.82{\sim}13.65g$ $CO_2$ $m^2d^{-1}$ 범위의 계절변화를 보였고, 온도가 높고 강우가 많았던 $7{\sim}9$월에는 비교적 온도가 낮았던 $5{\sim}6$월보다 토양호흡 속도가 낮았다. 토양호흡속도는 지온($r^2=0.800$) 및 기온($r^2=0.805$)과 유의한 지수함수적 관계를 보였다. 지온과 기온에 대한 토양호흡속도의 $Q_{10}$ 값은 각각 2.0과 1.9이었으며, 연간 총 토양 호흡량은 19.6ton $CO_2$ $ha^{-1}$ 이었다.

• 한국환경농학회지
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• 제42권3호
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• pp.211-219
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• 2023

중량식 라이시미터를 이용하여 사양질과 식질 토양에서 동계 작물인 청보리 재배 여부에 따른 양분 유출과 양분 수지를 평가하였다. 양분 유출과 관련된 지하 배수량은 식질에서 가장 많았으며, 동계 작물 재배 여부에 따른 토양 수분함량을 비교해보면 나지에서는 사양질과 식질 토양 모두 30-40%를 유지하였고, 청보리 재배구는 생육 재생기인 3-4월에 평균 증발산량이 평균 2.1-6.7 mm·day^-1이었으며, 토양 수분함량은 18.1-21.8%까지 낮아졌다. 동계작물 재배 시 봄철 생육재생기에 생체량이 증가함에 따라 증발산량도 증가하기 때문에 수분이 지상부로 이동하므로 양분의 지하유출을 예방할 수 있을 것으로 판단된다. 또한 사양질 토양에서 청보리의 재배에 따른 양분수지는 비료 공급량에 비해 작물 흡수량이 많아 음의 값을 나타냈으며, 토양에 집적된 양분을 이용했을 것으로 추측된다. 따라서 동계에 적정량의 비료를 주고 사료작물을 재배하면 경지 이용률을 높이고, 양분수지를 낮추는데 도움이 될 것으로 판단된다.

• 한국제4기학회지
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• 제14권1호
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• pp.57-63
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• 2000

월악산에 자라는 낙엽송의 연륜세포의 생장에 미치는 온난화의 영향을 시뮬레이션 모델로 예측하였다. 이 모델은 각 연륜의 세포(가도관) 폭 변이를 일 강수량과 기온으로 모사하는 수학식을 사용한다. 세포생장을 제한하는 조건을 기온, 일장, 그리고 계산된 수분수지로 추정한다. 이 모델을 적용한 결과 낙엽송의 계절생장에 가장 큰 영향을 주는 것은 4월과 5월의 토양수분조건과 강수량인 것으로 나타났다. 4~5월 기온 상승은 토양으로부터 수분 증발을 증가시켜 생장을 감소시켰다. 지구온난화(기온 $2^{\circ}C$ 상승)을 모델에 산정하였을 때 생장적기가 짧아졌고 전체 연륜 생장량을 25% 정도 감소시켰다.