• Article

    Modification of Hargreaves Equation Coefficient to Estimate Reference Evapotranspiration in Gangwondo
    Youngho Seo, Soojeong Lim, Sujeong Heo, Byeongsung Yoon, Sooyoung Hong, Younghak Park, and Daeki Hong
    Reference evapotranspiration (ET0) can be estimated using Hargreaves equation with temperature data alone. The equation has a tendency to overestimate for regions ... + READ MORE
    Reference evapotranspiration (ET0) can be estimated using Hargreaves equation with temperature data alone. The equation has a tendency to overestimate for regions of high relative humidity and to underestimate for regions of wind speed greater than 3 m s-1. The study was conducted to determine Hargreaves equation coefficient in 11 regions in Gangwondo by comparing ET0 determined by modified Hargreaves equation with ET0 by the FAO Penman-Monteith equation. The Penman-Monteith ET0 values were determined using the weather data including solar duration, air temperature, humidity, and wind speed for 11 weather stations in Gangwondo from 2007 to 2017. The modified Hargreaves coefficients for inland regions such as Chuncheon, Hongcheon, Cheorwon, Wonju, Inje, Yeongwol, Daegwallyeong, and Taebaek ranged from 0.00181 to 0.00199, less than the default value 0.0023. The modified coefficients for coastal regions such as Gangneung, Sokcho, and Donghae ranged from 0.00275 to 0.00302, greater than the default value. Modified Hargreaves ET0 using modified coefficients reduced root mean square error (RMSE) from 0.84 mm d-1 to 0.69 mm d-1 and increased Nash-Sutcliffe coefficient (NSC) from 0.69 to 0.78 compared with original Hargreaves ET0. Therefore the modified Hargreaves coefficients obtained from the study can provide more accurate ET0 estimates than using original default value by considering regional climate characteristics in Gangwondo. Modified Hargreaves coefficient for 11 regions in Gangwondo. Region Coefficient Region Coefficient Region Coefficient Chuncheon 0.00187 Inje 0.00195 Gangneung 0.00302 Hongcheon 0.00181 Yeongwol 0.00183 Sokcho 0.00275 Cheorwon 0.00192 Daegwallyeong 0.00218 Donghae 0.00284 Wonju 0.00193 Taebaek 0.00199 - COLLAPSE
    February 2019
  • Article

    Effect of Cold Stress on the Content of Minerals and Water Soluble Vitamins in Spinach (Spinacia oleracea)
    Young Eun Yoon, Saranya Kuppusamy, Song Yeob Kim, Jang Hwan Kim, and Yong Bok Lee
    To assess the effect of cold stress on the levels of minerals (C, N, P, K, Ca, Mg, Mn, Zn, Cu and ... + READ MORE
    To assess the effect of cold stress on the levels of minerals (C, N, P, K, Ca, Mg, Mn, Zn, Cu and Fe) and water soluble vitamins (B1, B2, B3, B5, B6, B9 and C) in spinach, an experiment was set up under greenhouse conditions and compared to field results. Levels of macro and micronutrients, except iron in spinach were unaffected by growth conditions and cold stress. The abundance of water soluble vitamins were most pronounced in greenhouse grown plants exposed to 14 and 21 days of cold stress. Significant increases in vitamin C (from 22.73 to 34.47 mg 100 g-1 dry matter) accumulation in stressed plants were observed, thus highlighting its role in plant defense mechanisms. Results indicate that cultivation of leafy vegetables in a greenhouse with low temperature (4 to 7°C) exposure for a shorter period (14 to 21 days) before harvest can improve the nutritional quality. Water soluble vitamin (WSV) contents of field- and greenhouse-grown spinaches. - COLLAPSE
    February 2019
  • Article

    The Effects of Biochar Made by Oaks on the Growth and Seedling Quality Index of Prunus sargentii in a Containerized Production System
    Woo Bin Youn, Loth Meng, Si Ho Han, Aung Aung, Min Seok Cho1, and Byung Bae Park*
    The purpose of this study is to investigate the effects of biochar mixed ratios made by oaks on the growth and quality ... + READ MORE
    The purpose of this study is to investigate the effects of biochar mixed ratios made by oaks on the growth and quality index of Prunus sargentii seedlings in a containerized seedling production system. We treated biochar made by oak charcoal with 10% and 20% volume ratio of the artificial soil including the untreated control and applied two levels of 0.5 and 1.0 g/L fertilization treatments. Generally, growth parameters including height, root collar diameter, and dry weight were decreased by biochar treatments and there were no fertilization effects. However, 10% biochar treatment significantly increased quality index by 26% compared to that of control. Our results suggested the oak charcoal, a kind of biochar, can be substituted up to 10% of the artificial soil in the containerized P. sargentii seedling production system and expect to increase the survival rate in the beginning of the plantation. Seedling quality index by the mixed ratio of oak biochar. - COLLAPSE
    February 2019
  • Article

    Zinc Adsorption Characteristics by Biochar Derived from Spent Coffee Grounds
    Jong-Hwan Park, Hong-Chul Kim, Seong-Heon Kim, Young-Jin Kim, Se-Won Kang, Ju-Sik Cho, and Dong-Cheol Seo
    Zinc (Zn) adsorption characteristics of biochar derived from spent coffee grounds (SCGB) were evaluated under various conditions. Zinc adsorption was well described ... + READ MORE
    Zinc (Zn) adsorption characteristics of biochar derived from spent coffee grounds (SCGB) were evaluated under various conditions. Zinc adsorption was well described by pseudo-second order and Langmuir isotherm models with maximum adsorption capacity of 26.6 mg g-1. Additional fitting of intraparticle model showed that Zn in SCGB was controlled by both external surface adsorption and intraparticle diffusion. As a result of adsorption of Zn on SCGB according to the initial pH, the adsorption capacity of Zn increased as pH increased from 2 to 6, but decreased dramatically from pH 7. The adsorption capacity of Zn by SCGB in the presence of other metals was remarkably reduced. In particular, the adsorption amount of Zn in the Pb and Zn complex solution was reduced by 82.9% compared with that of the Zn single solution, which is considered to be closely related to the properties of the metal itself such as electronegativity and hydrate radius. The FTIR demonstrated that Zn in SCGB was related to carbon and oxygen functional groups. Overall, SCGB could be applied as an adsorbent for Zn removal from aqueous solution, and its direct production through pyrolysis of spent coffee grounds could make it an economic option as absorbent for treating Zn-rich wastewater. Adsorption characteristics of zinc by SCGB under different initial zinc concentration (A) and contact time (B). - COLLAPSE
    February 2019
  • Article

    Taxonomical Classification and Genesis of Hoesu Series, New Series in Jeju Island
    Kwan-Cheol Song and Ho-Jun Kang
    Typifying pedon of Ora series distributed in the northern mid-mountainous areas and that of A Ora (Hoesu) series distributed in the southern ... + READ MORE
    Typifying pedon of Ora series distributed in the northern mid-mountainous areas and that of A Ora (Hoesu) series distributed in the southern mid-mountainous areas in Jeju Island were established. This study was conducted to classify Ora and A Ora series based on the second edition of Soil Taxonomy and to discribe the formation of Ora and A Ora series in Jeju Island. Morphological properties of typifying pedons of Ora and A Ora series were investigated and physico-chemical properties were analyzed according to Soil Survey Laboratory Methods Manual. The typifying pedon of Ora series established in the nothern mid-mountainous areas in Jeju Island has an umbric epipedon from a depth of 0 to 35 cm and a cambic horizon from a depth of 35 to 92 cm. That can be classified as Incepisol. It has an udic soil moisture regime and keys out as Udept. It has an umbric epipedon and keys out as Humudept. It has, throughout one or more horizons with a total thickness of 18 cm or more within 75 cm of the mineral soil surface, a fine-earth fraction with both a bulk density of 1.0 Mg m-3 and Al plus 1/2 Fe percentages (by ammonium oxalate) totaling more than 1.0. It can be classified by Andic Humudept. The typifying pedon has medial particle-size class, mixed mineralogy class, and thermic soil temperature regime. Therefore, it can be classified as medial, mixed, thermic family of Andic Humudept, not as fine silty, thermic family of Andic Eutrudept. The typifying pedon of A Ora series set up in the southern mid-mountainous areas in Jeju Ialand has an umbric epipedon from a depth of 0 to 42 cm and a cambic horizon from a depth of 42 to 101 cm. That contains oxalate extractable (Al + 1/2Fe) content equal to 2.0 or more, phosphate retention of 85% or more, and bulk density of 0.90 Mg m-3 or less from a depth of 0 to 160 cm. Therefore, it has an andic soil properties at that depth. It can be classified as Andisol. It has an udic soil moisture regime, and can be classified as Udand. Also it meets the requirements of Typic Hapludand. It has medial particle-size class, ferrihydritic mineralogy class, and thermic soil temperature class. Therefore it can be classified as medial, ferrihydritic, thermic family of Typic Hapludand. Ora series distributed in the northern and western mid-mountainous areas are classifyed as Inceptisols. But A Ora series distributed in the southern mid-mountainous areas are classifyed as Andisols. A Ora series distributed in the southern mid-mountainous areas in Jeju Island are established as Hoesu series, new series. In the western and northern coastal areas which have a relatively dry climate in Jeju Island, non-Andisols are widely distributed. Mean annual precipitation is increased and mean annual temperature is decreased remarkably with increasing elevation. In the western and northern mid-mountainous areas Andisols and non-Andisols are distributed simultaneously. Ora series distributed in the western and northern mid-mountainous areas are developed as Andic Humudepts. Hoesu series distributed in the southern mid-mountainous areas which have a humid climate are developed as Andisols. Laboratory data sheets of typifying pedons of Ora and Hoesu series. Soils Depth (cm) Horizon (-- Total --) (- Clay -) (- Silt -) (- - - - - - - - - - Sand - - - - - - - - - -) Clay Silt Sand Fine Coarse Fine Coarse VF F M C VC LT .002 .05 LT LT .002 .02 .05 .10 .25 .5 1 .002 -.05 -2 .0002 .002 -.02 -.05 -.10 -.25 -.50 -1 -2 - - - - - - - - - - - - - - - - - - - - - - - - - Pct of ˂ 2 mm (3A1) - - - - - - - - - - - - - - - - - - - - - - - - - Ora 0-20 Ap 22.9 71.6 5.5 41.3 30.3 0.9 1.5 1.2 1.2 0.7 20-35 AB 21.1 72.5 6.4 36.7 35.8 1.3 1.9 1.4 1.4 0.4 35-67 Bw1 19.3 73.1 7.5 35.2 37.9 1.9 2.3 1.6 1.3 0.4 67-92 Bw2 21.1 71.8 6.0 32.6 39.2 1.6 2.1 1.2 0.9 0.2 92-160 BC 25.3 64.9 9.8 24.6 40.3 2.5 3.7 2.0 1.3 0.3 A Ora 0-13 A 25.6 65.5 8.9 40.4 25.1 2.8 3.3 1.7 0.9 0.3 (Hoesu) 13-42 AB 28.1 64.4 7.5 36.8 27.6 2.6 2.9 1.2 0.6 0.2 42-72 Bw1 27.8 64.5 7.7 35.2 29.3 2.8 2.8 1.3 0.6 0.2 72-101 Bw2 27.5 65.4 7.1 34.7 30.7 2.5 2.4 1.2 0.7 0.3 101-160 BC 38.9 58.1 3.0 26.6 31.5 1.2 1.2 0.4 0.2 0 Soils Depth (cm) ( Base Sat ) CO3 as Res ( - - - - - - - - pH - - - - - - - - - - ) Acid Oxalate Extraction Sum NH4- CaCO3 NaF KCl CaCl2 H2O Opt Al Fe Si OAc ˂2 mm .01M Den 5C3 5C1 6E1g 8E1 8C1d 8C1f 8C1f 8J 6G12 6C9a 6V2 - - - - - - - Pct - - - - - - - ohms/cm 1:1 1:2 1:1 - - - Pct of ˂ 2 mm - - - Ora 0-20 15.0 20.2 4.6 5.0 5.6 0.60 0.92 0.09 20-35 11.5 15.8 4.5 4.9 5.5 1.13 1.38 0.20 35-67 6.9 9.7 4.5 4.8 5.7 1.53 1.32 0.40 67-92 14.1 16.4 4.5 4.9 6.0 0.97 1.04 0.17 92-160 18.5 21.6 5.0 5.0 6.1 1.01 1.15 0.18 A Ora 0-13 10.8 13.7 4.6 5.0 5.7 2.31 2.20 0.41 (Hoesu) 13-42 8.7 11.6 4.6 4.9 5.8 2.25 2.25 0.40 42-72 9.4 12.6 4.6 5.0 5.9 2.24 2.21 0.38 72-101 8.2 11.9 4.6 5.0 5.9 2.29 2.27 0.39 101-160 15.8 20.1 4.6 5.2 6.4 1.68 2.26 0.35 - COLLAPSE
    February 2019
  • Article

    Fertilizer NPK Recommendations for Kiwi Cultivation Based on Soil Testing in Jeju
    Ho-Jun Kang
    This study was carried out in order to determine the Kiwi fruit (Actinidia deliciosa cv. Hayward) fertilization standards in Jeju. Soil chemical ... + READ MORE
    This study was carried out in order to determine the Kiwi fruit (Actinidia deliciosa cv. Hayward) fertilization standards in Jeju. Soil chemical properties and mineral contents of leaves, and the amounts of fertilizers were investigated in 35 places of volcanic ash soils and in 15 places of non volcanic ash soils. Tests were made to provide the most resonable fertilizer recommendation for kiwi fruit based on soil analytical data and leaf mineral contents response to the NPK fertilizers. Average pH was 6.0, organic matter (OM) content was 113 g kg-1, available P2O5 content was 288 mg kg-1, and exchangeable K, Ca, and Mg were 1.61, 10.5, and 3.1 cmolc kg-1, respectively for volcanic ash soils. Also, Average pH was 5.7, organic matter (OM) content was 48.3 g kg-1, available P2O5 content was 541 mg kg-1, and exchangeable K, Ca, and Mg were 1.45, 6.6, and 2.2 cmolc kg-1, respectively for non volcanic ash soils in Jeju. Available phosphorus contents of volcanic ash soils, were lower than those of non volcanic ash soils. However, soil organic matter contents were higher than those of the optimun range. P and Mg contents of kiwi fruit leves were lower in comparison with a suitable standard leaf, but K and Ca contents were higher. The amounts of N, P2O5, and K2O fertilizers applied to farmers' fields were N 22.4 kg 10a-1, P2O5 21.6 kg 10a-1, and K2O 18.3 kg 10a-1 in volcanic ash soils. Those of non volcanic ash soils were 17.1 kg 10a-1, 13.5 kg 10a-1 and 13.3 kg 10a-1. The Yield had no difference between the volcanic ash soils and non volcanic ash soils. The relationship between soil chemical properties and amounts of fertilizer use were observed. The soil organic matter contents werenegatively correlated with amounts of nitrogen fertilizers. Soil available phosphorus contents were negatively correlated with amounts of phosphate fertilizer. Also, Soil exchangeable potassium contents showed negative correlation with amount of potassium fertilizer. Recommended fertilizer amounts for N and P2O5 were determined by using the soil OM and available P2O5 contents. Recommended K2O fertilizer were determined by exchangeable K contents in soils. Amounts of standard fertilization N-P2O5-K2O fertilizer in volcanic ash soils were 16.5-16.5-11.1 kg/10a for kiwi fruit of 8 years or older, and 13.5-8.8-9.0 kg/10a in non volcanic ash soils. N, P2O5, and K2O standard fertilizer amount by tree ages in volcanic ash soils and non volcanic ash soils in Jeju. Tree ages Volcanic ash soil Non volcanic ash soil N P2O5 K2O N P2O5 K2O (kg 10a-1) 1 3.2 3.3 2.2 2.7 1.8 1.8 2-3 5.8 5.7 3.9 4.7 3.1 3.2 4-5 9.0 9.0 6.1 7.4 4.8 5.0 6-7 12.4 12.3 8.3 10.1 6.6 6.8 8 more 16.5 16.5 11.1 13.5 8.8 9.0 - COLLAPSE
    February 2019
  • Article

    Study on Soil Erosion and Physical Characteristics of Jeju Volcanic Ash Soils Under a Rainfall Simulator Condition
    Won-Pyo Park and Ho-Jun Kang
    The objective of this study is to determine the effects of physical properties of soils on soil erosion under a rainfall simulator ... + READ MORE
    The objective of this study is to determine the effects of physical properties of soils on soil erosion under a rainfall simulator. The soil samples were collected from five sites of dark brown soil (DBS), six sites of very dark brown volcanic ash soil (VDBAS), and eight sites of black volcanic ash soil (BVAS) in Jeju Island. The rainfall simulator, which ran for 30 minutes at a slope gradient of 10%, determined the amounts of soil erosion, infiltrated water, and runoff water. The particle size distribution, water-stable aggregates distribution, bulk density, organic matter content, and saturated hydraulic conductivity in soils were analyzed as well. The amounts of soil erosion gradually increased and reached a steady state after 20 minutes. The amounts of soil erosion in BVAS were higher than that in other soils. It also correlated positively with the amounts of runoff water and related negatively to the amounts of infiltrated water. The amounts of soil erosion in DBS and BVAS had a significant negative correlation with some particle size fractions and saturated hydraulic conductivity (p<0.05). A significant positive correlation was observed between the amounts of soil erosion and the water-stable aggregates with the size smaller than 1 mm in DBS and VDVAS (p<0.05). The bulk density and organic matter content did not significantly affect the amount of soil erosion. These results concluded that the physical properties of soils affecting the amount of soil erosion varied among the color of soils in Jeju Island. It is suggested that the values of soil erodibility factor for the volcanic ash soils of Jeju Island need to be estimated with an alternative algorithm to predict the amount of soil erosion. Relationship between the amount of soil erosion and runoff (a) and infiltration water (b) in dark brown soil (▲ ), very dark brown volcanic ash soil (○), and black volcanic ash soil (●). **Significant difference at 1%, *Significant difference at 5%. - COLLAPSE
    February 2019
  • Short Communication

    Evaluation of Barley-Hairy Vetch Mixed Cropping as Green Manure for Biomass and Nitrogen Production
    Young Eun Yoon, Jang Hwan Kim, and Yong Bok Lee
    The mixtures of legumes and non-legume cropping after rice cultivation are widely used for green manure production in Korea. However, there is ... + READ MORE
    The mixtures of legumes and non-legume cropping after rice cultivation are widely used for green manure production in Korea. However, there is little information on how the species proportion may affect land use efficient and green manure quality. In this study, green manure N accumulation and Land Equivalent Ratio (LER) was tested with differential seeding ratios using barley and hairy vetch as a green manure. The species proportion influences the biomass production (ranging from 10.74 to 13.34 Mg ha-1) and N accumulation (ranging from 256.3 to 249.7 kg ha-1). The N accumulation in hairy vetch mixed, even at 25% of its full sowing proportion, was three times higher than that of pure stand of barley. The N accumulation of barley increased linearly with hairy vetch proportion on the total biomass. The mixtures were more efficient than the pure crops in terms of biomass production (LER>1) and N accumulation (LER>1). Therefore, this results suggest that adopting mixture barley with hairy vetch produce a high amount of biomass with higher quality compared with pure stand of barley. Land equivalent ratio (LER) for different sowing ratio of barley and hairy vetch in a mixed cropping. Barley and hairy vetch were grown in mixtures with varying seed ratios, relative to full sowing rate, i.e., 25% barley + 75% hairy vetch (B25H75), 50% barley + 50% hairy vetch (B50H50), and 75% barley + 25% hairy vetch (B75H25). - COLLAPSE
    February 2019