• Title/Summary/Keyword: Agricultural Conditions

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Soil Carbon Storage in Upland Soils by Biochar Application in East Asia: Review and Data Analysis (바이오차를 이용한 밭 토양 탄소 저장: 동아시아 지역 연구 리뷰 및 데이터 분석)

  • Lee, Sun-Il;Kang, Seong-Soo;Choi, Eun-Jung;Gwon, Hyo-Suk;Lee, Hyoung-Seok;Lee, Jong-Mun;Lim, Sang-Sun;Choi, Woo-Jung
    • Korean Journal of Environmental Agriculture
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    • v.40 no.3
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    • pp.219-230
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    • 2021
  • BACKGROUND: Biochar is a solid material converted from agricultural biomass such as crop residues and pruning branch through pyrolysis under limited oxygen supply. Biochar consists of non-degradable carbon (C) double bonds and aromatic ring that are not readily broken down by microbial degradation in the soils. Due to the recalcitrancy of C in biochar, biochar application to the soils is of help in enhancing soil carbon sequestration in arable lands that might be a strategy of agricultural sector to mitigate climate change. METHODS AND RESULTS: Data were collected from studies on the effect of biochar application on soil C content conducted in East Asian countries including China, Japan and Korea under different experimental conditions (incubation, column, pot, and field). The magnitude of soil C storage was positively correlated (p < 0.001) with biochar application rate under field conditions, reflecting accumulation of recalcitrant black C in the biochar. However, The changes in soil C contents per C input from biochar (% per t/ha) were 6.80 in field condition, and 12.58 in laboratory condition. The magnitude of increment of soil C was lower in field than in laboratory conditions due to potential loss of C through weathering of biochar under field conditions. Biochar production condition also affected soil C increment; more C increment was found with biochar produced at a high temperature (over 450℃). CONCLUSION: This review suggests that biochar application is a potential measures of C sequestration in agricultural soils. However, as the increment of soil C biochar was affected by biochar types, further studies are necessary to find better biochar types for enhanced soil C storage.

Changes in Quality of Welsh Onion (Allium fistulosum L.) during the Freezing Storage Period under Different Freezing Conditions (냉동조건에 따른 대파의 냉동저장 중 품질변화)

  • Kim, Seok-Young;Kim, Hee-Sun;Kim, Jin-Se;Han, Gwi-Jung
    • Korean journal of food and cookery science
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    • v.32 no.6
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    • pp.665-676
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    • 2016
  • Purpose: This study was conducted to find the optimal freezing method and storage conditions for welsh onion. Methods: Cut welsh onions (0.3 cm) were packed in nylon/linear low density polyethylene (LLDPE) film bags, and frozen utilizing still-air freezing at -$20^{\circ}C$ (SAF20) and -$40^{\circ}C$ (SAF40), and immersed-liquid freezing at -$40^{\circ}C$ (ILF40); they were then stored at -$20^{\circ}C$ for 7 months. During storage, quality characteristics were measured monthly. Results: Drip loss was the lowest in the ILF40 packaging. Color difference in the stem (white part) did not differ significantly according to freezing conditions and storage time. Color difference in the leaf (green part) and stem was the lowest in SAF20. pH remained unchanged, while total aerobic bacterial count, pyruvic acid and moisture content decreased during storage. Pyruvic acid content of ILF40 was the highest among the freezing treatments. Fructose and glucose contents increased gradually during storage. Citric acid, malic acid, succinic acid and fumaric acid contents were unaffected, regardless of the freezing conditions. Conclusion: The optimal freezing method for welsh onions with the least quality changes was determined to be immersed liquid freezing, following by preservation up to 7 months by freeze-storing.

Adsorption characteristics of NH4-N by biochar derived from pine needles

  • Kang, Yun-Gu;Lee, Jun-Young;Chun, Jin-Hyuk;Lee, Jae-Han;Yun, Yeo-Uk;Oh, Taek-Keun
    • Korean Journal of Agricultural Science
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    • v.48 no.3
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    • pp.589-596
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    • 2021
  • Nitrogen applied to soil is highly prone to leaching and volatilization leading to gaseous emissions of nitrous oxide (N2O) and ammonia (NH3) which are of great environmental concern. Usage of biochar to reduce the discharge of nitrogen to the environment has attracted much interest in the recent past. Biochar is produced by pyrolyzing various biomasses under oxygen-limited conditions. Biochar is a carbonized material with high adsorptive powers for not only plant nutrients but also heavy metals. The objective of this study was to investigate the adsorption characteristics of NH4-N onto biochar made from pine needles. The biochar was produced at various pyrolysis temperatures including 300, 400 and 500℃ and holding times of 30 and 120 minutes. The Langmuir isotherm was used to evaluate the adsorption test results. The chemical properties of the biochar varied with the pyrolysis conditions. In particular, the pH, EC and total carbon content increased with the increasing pyrolysis conditions. The rate of adsorption of NH4-N by the biochar decreased with the increasing pyrolysis conditions. Of these conditions, biochar that was pyrolyzed at 300℃ for 30 minutes showed the highest adsorption rate of approximately 0.071 mg·g-1. Thus, the use of biochar pyrolyzed at low temperatures with a short holding time can most efficiently reduce ammonia emissions from agricultural land.

Optimization of the extraction process of high levels of chlorogenic acid and ginsenosides from short-term hydroponic-cultured ginseng and evaluation of the extract for the prevention of atopic dermatitis

  • Lee, Tae Kyung;Lee, Ji Yun;Cho, Yeon-Jin;Kim, Jong-Eun;Kim, Seo Yeong;Park, Jung Han Yoon;Yang, Hee;Lee, Ki Won
    • Journal of Ginseng Research
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    • v.46 no.3
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    • pp.367-375
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    • 2022
  • Background: Short-term hydroponic-cultured ginseng (sHCG), which is 1-year-old ginseng seedlings cultivated for 4 weeks in a hydroponic system, is a functional food item with several biological effects. However, the optimal extraction conditions for sHCG, and the bioactivity of its extracts, have not been evaluated. Methods: Chlorogenic acid (CGA) and ginsenoside contents were evaluated in sHCG, white ginseng (WG), and red ginseng (RG) using high-performance liquid chromatography. Response surface methodology (RSM) was used to optimize the extraction conditions (temperature and ethanol concentration) to maximize the yield of dry matter, CGA, and four ginsenosides (Re, Rg1, Rb1, and Rd) from sHCG. The optimal extraction conditions were applied to pilot-scale production of sHCG extracts. The expression levels of tumor necrosis factor (TNF)-α/interferon (IFN)-γ-induced thymic and activation-regulated chemokines (TARC/CCL17) were measured after treatment with sHCG, WG, and RG extracts, and the effects of their bioactive compounds (CGA and four ginsenosides) on human skin keratinocytes (HaCaTs) were evaluated. Results: CGA and four ginsenosides, which are bioactive compounds of sHCG, significantly inhibited TNF-α/IFN-γ-induced TARC/CCL17 expression. The optimal sHCG extraction conditions predicted by the RSM models were 80 ℃ and 60% ethanol (v/v). The sHCG extracts produced at the pilot scale under optimal conditions greatly alleviated TNF-α/IFN-γ-induced TARC/CCL17 production compared with WG and RG extracts. Conclusions: Pesticide-free sHCG extracts, which contain high levels of CGA and the ginsenosides Re, Rg1, Rb1, and Rd as bioactive compounds, may have therapeutic potential for atopic diseases.

Growth and yield responses of rice varieties to various soil water deficit conditions under different soil types

  • Kikuta, Mayumi;Samejima, Hiroaki;Magoti, Rahab;Kimani, John M.;Yamauchi, Akira;Makihara, Daigo
    • Proceedings of the Korean Society of Crop Science Conference
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    • 2017.06a
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    • pp.322-322
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    • 2017
  • To avoid drought stress under rainfed upland conditions, it is important for rice to efficiently utilize water at shallow soil layers supplied by rainfall, and access to water retained in deer soil layers. The root developmental characteristics of rice, which play important role in the adaptability to drought conditions, vary depending on the variety. Moreover, water availability for plant differs depending on the soil types that have different physical properties such as water holding capacity, permeability, capillary force, penetration resistance, etc. In this study, we evaluated growth and yield responses of rice varieties to various soil water deficit conditions under three different soil types. The experiment was conducted in a plastic greenhouse at the Kenya Agricultural and Livestock Research Organization-Mwea from October 2016 to January 2017. Two upland varieties (NERICA 1 and 4) and one lowland variety (Komboka) were grown in handmade PVC pots (15.2 cm diameter and 85.0 cm height) filled with three different types of soil collected from major rice-growing areas of the country, namely black cotton (BC), red clay (RC), and sandy clay (SC). Three watering methods, 1) supplying water only from the soil surface (W1), 2) supplying water only from the bottom of the pots (W2), and 3) supplying water both from the soil surface and the bottom of pots (W3), were imposed from 40 days after sowing to maturity. Soil water content (SWC) at 20, 40, and 60 cm depths was measured regularly. At the harvesting stage, aboveground and root samples were collected to determine total dry weight (TDW), grain yield, and root length at 0-20, 20-40, 40-60, and 60-80 cm soil layers. Irrespective of the watering methods, the greatest root development was obtained in RC, while that in BC was less than other two soils. In BC, the degree of yield reduction under W1 was less than that in RC and SC, which could be attributed to the higher water holding capacity of BC. In RC, the growth and yield reduction observed in all varieties under W1 was attributed to the severe drought stress. On the other hand, under W2, SWC at the shallow soil depth in RC was maintained because of its higher capillary force compared with BC and SC. As the result, growths and yields in RC were not suppressed under W2. In SC, deep root development was not promoted by W2 irrespective of the varieties, which resulted in significant yield losses. Under W1, the rice growth and yield in SC was decreased although shallow root development was enhanced, and the stomatal conductance was maintained higher than RC. It was suspected that W1 caused nutrients leaching in SC because of its higher permeability. Under rainfed conditions, growth and yield of rice can be strongly affected by soil types because dynamics of soil water conditions change according to soil physical properties.

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Optimization of Ethanol Extraction Conditions for Antioxidants from Zizyphus jujuba Mill. Leaves Using Response Surface Methodology (반응표면분석법을 이용한 대추잎 항산화물질의 에탄올추출조건 최적화)

  • Min, Dul-Lae;Lim, Seok-Won;Ahn, Jun-Bae;Choi, Young-Jin
    • Korean Journal of Food Science and Technology
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    • v.42 no.6
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    • pp.733-738
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    • 2010
  • The leaves of Zizyphus jujuba have been used for various purposes including medicine and nutrition. In this study, the conditions for the ethanol extraction of antioxidant from Zizyphus jujuba were optimized using response surface methodology (RSM). A Box-Behnken design containing 15 experimental runs with three replicates was employed to study the effects of solvent extraction conditions such as extraction temperature ($^{\circ}C$, $X_1$), extraction time (min, $X_2$), and ethanol concentration (%, $X_3$) on the extraction yield of antioxidants from Zizyphus jujuba. The yields of total polyphenols and total flavonoid, and electron donating activity (EDA) were considered as response variables. The second-order polynomial model gave a satisfactory description of the experimental results showing different patterns of extraction conditions with variation in the linear, quadratic, and interaction effects of the independent variables. Based on four-dimensional RSM, one of the optimized sets of conditions was 45% ethanol, $45^{\circ}C$, and an extraction time of 15 min. Under the optimal conditions, the predicted values were 177.64 mg/g dry basis, 35.99 mg/g dry basis, and 86.14% Vit.C equivalents for total polyphenols, total flavonoids, and EDA, respectively. The experimental values showed good agreements with the predicted values.

Studies on the Genesis of Ginseng Rust Spots

  • Wang, Yingping;Li, Zhihong;Sun, Yanjun;Guo, Shiwei;Tian, Shuzhen;Liu, Zhaorong
    • Journal of Ginseng Research
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    • v.21 no.2
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    • pp.69-77
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    • 1997
  • In order to explain the connection between ginseng rust spot and soil ecological conditions, the bed soils and ginseng roots were sampled at different microrelief units and the reducing substances of the bed soils and iron forms of the ginseng root epi dermises were determined. The results showed that the occurrence of the rust spot was connected with the ecological conditions of the soils and the metabolism of the plant which was caused by the excessive $Fe^{2+}$ in the soil solution. Ginseng rust spot was the enrichment of iron which was mainly composed of organic complex irons. Including active ferrous active ferric and non active ferric forms and they were transformed into each other following the change of soil moisture and temperature regimes. According to the regularity of growth and decline of reducing substances in soil and rust index of ginseng roots as well as the difference of adaptability to excessive $Fe^{2+}$ in soil among different year-old seeding, a new comprehensive measure based on the connection of ameliorating soil and improving cultivation system was recommended to prevent the occurrence of ginseng rust spot.

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Study on Reform of Development Regulations in Greenbelt - Focused on Agricultural, Forestry and Fisheries Facilities - (그린벨트내 개발행위허가 규제제도의 변천에 관한 연구 - 농림수산업용 시설을 중심으로 -)

  • Lee, Sang-Won;Sato, Yohei
    • Journal of Korean Society of Rural Planning
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    • v.6 no.1 s.11
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    • pp.10-18
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    • 2000
  • The objective of this study is to analyze 1) the law system in relation with the development permissions 2) characteristics of the development permissions change 3) especially focusing on the development permissions changes in agricultural, forestry and fisheries facilities in light of socio - economic conditions in Korea Greenbelt. The following results were obtained: 1) The purpose of Greenbelt in Korea is to control the land use in order to protect the surrounding areas from urbanization. 2) During the 1990s, the number of formulated development regulations increased one and half times than that of the previous decades(1970s 1980s). The main reasons are advancements of local autonomy and democratization. 3) Three patterns were observed with respect to ease the regulations in agricultural, forestry and fisheries facilities those are: (1) increase in types of businesses ; (2) increase the maximum area permitted ; (3) decrease in qualification for establishing facilities. 4) There were few development permissions in a agricultural, forestry and fisheries facilities in consideration to the regional agricultural condition. The development permissions were only during the period of restricted to use ($1979.12{\sim}1993.11$). We propose that the authority of development permission should be given to the local autonomy government, because the local government has the knowledge of its individual agricultural conditions.

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Effects of Temperature and Humidity on Fungal Occurrence in Dried Red Pepper during Storage

  • Kim, Sosoo;Baek, Seul Gi;Hung, Nguyen Bao;Kim, Se-Ri;Jang, Ja Yeong;Kim, Jeomsoon;Lee, Theresa
    • Research in Plant Disease
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    • v.27 no.4
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    • pp.155-163
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    • 2021
  • Dried red peppers are frequently contaminated with mycotoxins during storage. To determine the effect of storage environments on fungal occurrence and subsequent mycotoxin accumulation in dried red peppers, we monitored red pepper powder and whole fruit samples for fungal occurrence under various temperatures and relative humidity (RH) conditions during 340 days. Fungal occurrences fluctuated in both pepper forms throughout the storage but they were higher in pepper powder than whole one, higher under low temperatures (-20℃, 0℃, or 4℃) than others (10℃, 25℃, or 30℃), and higher under RH 93% than RH 51% and 69% in both peppers. The samples exhibiting high fungal occurrences were associated mainly with dominant species such as Aspergillussydowii, Penicillium solitum, P. roqueforti, P. polonicum, or P. chrysogenum. Mycotoxigenic species, including A. flavus, A. ochraceus, A. westerdijkiae, A. tubingensis, and P. citrinum, were also detected throughout the samples. Although mycotoxins were not detected in the samples, mycotoxigenic potential of A. flavus, A. ochraceus, and A. westerdijkiae isolates were confirmed. These results show that low temperatures (-20℃, 0℃, or 4℃) and/or high surrounding RH (>93%) are not safe environments for storage of dried red peppers as fungal growth can occur under these conditions.