• Original research article

    Effect of Phosphorus Fertigation on Concentration of Soil Available Phosphate and Growth of Green Onions (Allium fistulosum L.) in Open Field
    Yejin Lee, Chanwook Lee, Hyejin Park, and Yosung Song
    Phosphorus (P) is an essential mineral nutrient, which is easily precipitated and/or absorbed in the soil, and thus P use efficiency (PUE) … + READ MORE
    Phosphorus (P) is an essential mineral nutrient, which is easily precipitated and/or absorbed in the soil, and thus P use efficiency (PUE) of crops is relatively low. The spilt application of P through fertigation is considered an alternative method to improve the PUE. To evaluate the possibility, we grew upland green onions under different levels of P fertigation [no P, P100 (basal):F0 (fertigation), P50:F50, and P0:F100] and analyzed green onion growth, soil available P2O5 concentration, and PUE. Fertigation rate was adjusted based on soil diagnosis (N-P2O5-K2O = 182-40-166 kg ha-1), and green onions were grown from May to early November 2022. Dry weight of green onion at harvesting stage responded positively to increasing fertigation rates (e.g., P50:F50 and/or P0:F100). Soil available P2O5 was the highest at early growth stage in the P100:F0, and showed a trend of gradual decrease throughout the experiment. Interestingly, soil available P2O5 from the P0:F100 remained consistent during the whole growing season. P uptake of green onion was significantly greater in the P0:F100 than the basal fertilization, and the PUE of P0:F100 was 61.5%. Taken the results together, the fertigation of P for green onion production was effective not only in increasing crop yield but also in supplying crop-available P. In conclusion, this work suggests that the fertigation of P can be a better method to ensure yield of green onion through improved PUE. Dry weight, agronomic efficiency and phosphorus use efficiency of green onion according to phosphorus application ratio by fertigation. Ratio of P fertilization (%) Dry weight (kg ha-1) Agronomic efficiency (%) Phosphorus use efficiency (%) Control (P 0) 4.1 ± 0.17 c - - P100:F0 5.7 ± 0.80 b 3.9 ± 2.08 ns 26.6 ± 9.70 b P50:F50 6.0 ± 0.96 ab 4.8 ± 2.53 42.0 ± 19.60 ab P0:F100 6.8 ± 0.24 a 6.8 ± 0.66 61.5 ± 15.38 a Within each variable, means followed by the same letter are not differ significantly at p < 0.05 (DMRT). ns, no significant. - COLLAPSE
    30 November 2023
  • Original research article

    Life Cycle Assessment of Greenhouse Gas Emission of Rice Cultivation under Minimum Tillage in the Gimje, South Korea
    Ju-Hyeon Jin, Hyun-Cheol Jeong, Sun-Il Lee, Hyoung-Seok Lee, Hye-Ran Park, Ye-Seul Yu, Jong-Mun Lee, Yun-Ho Lee, and Hyo-Suk Gown
    The minimum tillage is a method of reducing energy consumption and greenhouse gas emissions by only tilling the part of areas where … + READ MORE
    The minimum tillage is a method of reducing energy consumption and greenhouse gas emissions by only tilling the part of areas where crops are planted. Until now, most studies have estimated greenhouse gas emissions only from the gases emitted during crop cultivation in rice paddy. However, greenhouse gases are also emitted from agricultural material (energy, fertilizers, pesticide, and other materials) inputs. Therefore, this study aims to comprehensively estimate greenhouse gas emissions from agricultural material inputs and minimum tillage conducted paddy during rice cultivation. The experiment was conducted in rice paddy from Gimje, South Korea, where conventional tillage and minimum tillage were implemented. Greenhouse gas emissions were obtained by direct measurement of methane (CH4) and nitrous oxide (N2O) emissions from rice paddy and calculation using life cycle assessment (LCA) for emissions from agricultural material input. The results showed that direct GWP during crop growth were 1.42 Mg CO2-eq. ha-1 in conventional tillage, and 1.02 Mg CO2-eq. ha-1 in minimum tillage. Greenhouse gas emissions from the input of agricultural materials were 0.84 Mg CO2-eq. ha-1 in conventional tillage and 0.63 Mg CO2-eq. ha-1 in minimum tillage. Minimum tillage (1.65 Mg CO2-eq. ha-1) was lower in the total greenhouse gas emissions (direct emissions + emissions from agricultural material inputs) than conventional tillage (2.26 Mg CO2-eq. ha-1). This is a result indicating that greenhouse gas emissions are greatly affected by direct emission in paddy and energy input, which could reduce greenhouse gas emissions when the minimum tillage was applied than the conventional tillage. It is expected that greenhouse gas emission reduction strategies in the agricultural sector could be reduced by applying minimum tillage to cropland and reducing the use of agricultural material. Total greenhouse gas emission of conventional tillage and minimum tillage treatment during rice cultivation in paddy. The same letters indicate a not significant difference between treatment (p < 0.05, t-test). ns indicate a not significant. - COLLAPSE
    30 November 2023
  • Original research article

    Effects of Water Management Practices on Methane Emissions and Rice Yields in East Asian Paddy Fields: A Regional-Scale Meta-Analysis
    Jong-Mun Lee, Hyun-Cheol Jeong, Hyoung-Seok Lee, Hye-Ran Park, Guen-Sik Kim, and Sun-Il Lee
    Paddy fields are considered one of the most important sources of anthropogenic methane (CH4) emissions. Drainage of the flooded soils … + READ MORE
    Paddy fields are considered one of the most important sources of anthropogenic methane (CH4) emissions. Drainage of the flooded soils can reduce CH4 substantially, but rice yields can be variable depending on soil drainage. Therefore, to reduce this variability, water management effects on CH4 emissions and rice yields were comprehensively analyzed in paddy fields of countries similar to Korea. Here, we selected 161 observations of water management and 174 observations of rice yields from 28 articles and conducted a regional-scale meta-analysis of the effects of water management practices on CH4 emissions and rice yields in paddy fields. As a result of the analysis, we found that water management practices in East Asian paddy fields reduced methane by 60.5%. Water management practices in paddy fields decreased rice yield by 5.8% but there was no significant. The water management practices of the paddy fields with a high CH4 emission reduction effect and no impact on rice yields were alternating wet and dry (AWD), flooding-drainage-reflooding (FDF), and moist irrigation (MI) practices. Therefore, it is considered that the above three practices can be applied in Korea. The results of this study are expected to predict CH4 emissions and rice yields generated by water management practices in East Asian rice paddies in the future and be used as basic data for the development of national unique coefficients. A response ratio of CH4 emissions (A) and rice yields (B) by water management types. - COLLAPSE
    30 November 2023
  • Original research article

    Evaluating Soil Loss in a Kimchi Cabbage Cropping System in the Highlands of Gangwon, Korea
    Yang-Min Kim, Mavis Badu Brempong, Gye-Ryeong Bak, and Jeong-Tae Lee
    Soil loss due to water erosion is a common phenomenon, which affects Kimchi cabbage (KC) productivity in the highland regions of Gangwon … + READ MORE
    Soil loss due to water erosion is a common phenomenon, which affects Kimchi cabbage (KC) productivity in the highland regions of Gangwon State Government. It is important to estimate soil losses in these cropping systems to provide basis for proper soil conservation measures. This research was conducted at the Highland Agriculture Research Institute to evaluate soil losses during KC cultivation and post-harvest in 2, 7 and 15% slope lysimeters in the 2021/2022 and 2022/2023 growing seasons. Cabbage residue was spread on the land post-harvest, after which it decomposed and was succeeded by volunteer grass. Rainfall amounts and intensities, percent soil coverage, soil losses and cover management factors (C factor) were investigated. Soil losses ranged from 0 - 2.689 tons ha-1 in 2% slope, 0 - 13.818 tons ha-1 in 7% slope and 0 - 85.596 tons ha-1 in 15% slope lysimeters in both KC cultivated land and bare land. However, soil losses under KC cultivation were always in minimal sections of the range. The order of importance for the soil loss contributors was as follows: rainfall intensity > rainfall amount > percent soil cover. Reduction in C factors as slope gradients increased (in both years) showed that KC was more efficient at reducing soil losses at steeper slopes. Post-harvest soil loss depended largely on rainfall amounts received, which directly affected the rate of cabbage residue decomposition and the length of time land may be uncovered. It was concluded that growing KC in the highland region conserves soil, however, it is equally important to grow cover crops after KC harvest to keep the soil covered for longer. Cover crops may also replenish soil fertility if tilled back into the soil before the next KC growing season. Relationships between soil losses and rainfall intensities under KC cultivation in 2, 7 and 15% slope lysimeters (using data points from the 2021/2022 and 2022/2023 experimental years). - COLLAPSE
    30 November 2023
  • Original research article

    Assessing Soil Organic Carbon Stock and Stability in Volcanic Grasslands: Implications for Climate Change Mitigation Potential and Management Levels
    Ye Lim Park, You Jin Kim, Jun Ge Hyun, Jeong Sung Jung, and Gayoung Yoo
    Volcanic grassland has a high soil organic carbon (SOC) stock, making it important for climate change mitigation. This study analyzed SOC stock … + READ MORE
    Volcanic grassland has a high soil organic carbon (SOC) stock, making it important for climate change mitigation. This study analyzed SOC stock in volcanic grassland soils and assessed the potential of volcanic grassland as a carbon sink by identifying the effect of management on SOC stock and stability. Soil samples in Jeju were collected from eight sites of generally well-managed grasslands (nominally-managed grassland, NG: applying fertilizer once annually and plant cover rate is 60 - 80%), which is considered as the representative SOC stock of volcanic grassland soil. To identify whether SOC stock increased by improved management (improved grassland, IG: applying fertilizer twice annually and plant cover rate is over 80%), soil samples were collected from two IG sites. Soil samples from NG and IG were analyzed for their SOC stock and stability using SOC fractionation. Our results revealed that the SOC stock of NG was 95 ton C ha-1. It was 19% higher than the default value (80 ton C ha-1) for grassland corresponding to a warm temperate climate suggested by IPCC 2006 Guidelines for National Greenhouse Gas Inventories. The SOC stock in the IG (150 ton C ha-1) was significantly higher than NG (95 ton C ha-1) by 58%. Especially, most of the increased SOC stock was stored in the stable fraction of Micro_POC (particulate organic carbon in microaggregate). Consequently, improved management of volcanic grassland in Jeju has the potential to offset 29% of carbon emissions from Jeju’s agricultural sector, underlining the importance of volcanic grasslands in climate change mitigation strategies. Improved management in volcanic grasslands boosts SOC quantity and quality, aiding climate change mitigation. - COLLAPSE
    30 November 2023
  • Original research article

    Variation Characteristics on Soil Physical Properties of Paddy Fields in Korea
    Seung-Oh Hur, Jeong-Woo Sohn, Jung-Hun Ok, and Seon-Ah Hwang
    The monitoring of soil physical properties of paddy fields is to be conducted in accordance with the notification (No. 2017-12) of the … + READ MORE
    The monitoring of soil physical properties of paddy fields is to be conducted in accordance with the notification (No. 2017-12) of the Rural Development Administration of Korea. The monitoring began in 2007 and was also monitored in 2011, 2012, 2015, and 2019. This study was conducted to evaluate the trends of these monitoring results by year. The main soil series of the paddy soils monitored were centered on soils such as Jisan-series, which had a large area distribution, and the topography was mainly distributed in valley/alluvial fan and flat areas like as river alluvium. In addition, most of the soil texture consisted of sandy loam, loam, and silt loam. The bulk density of the paddy subsoil and plowing depth have been showing an increasing trend until 2019 from 2007. The plowing depth is less than 20 cm, which is the standard for determining appropriate soil depth, but in 2019, it was 19.3 cm, approaching the appropriate standard. The distribution ratio of bulk density of subsoil exceeding the standards notified by the Rural Development Administration had been exceeding 80% since 2012. Soil organic matter content in paddy fields tended to increase in both topsoil and subsoil. The hardness of subsoil exceeded 20 mm which is the appropriate standard for paddy soil, except in 2019. As a result, it is believed that the plowing depth is increased by the introduction of large agricultural machinery, etc., making it possible to plow the soil deeper. However, the introduction of large agricultural machinery deteriorates the bulk density and hardness of the soil, so it is necessary to spread soil improvement methods such as subsoil crushing. It was also assessed that soil improvement, such as lowering the bulk density by increasing the organic matter content through continuous input of organic matter into the soil, was necessary. Distribution of soil texture during soil physical properties monitoring. - COLLAPSE
    30 November 2023
  • Original research article

    Temporal Trends in Available Phosphorus Across Four Types of Agricultural Fields from 2013 to 2020
    Jeong Gu Lee, Min-Hye Park, Myung-Sook Kim, Tae-Goo Lee, Ha-il Jung, Seung-Gyu Lee, Seon-Hye Baek, and Eun-Jin Lee
    Phosphorus (P) is a vital nutrient for global agriculture, playing a pivotal role in crop germination and growth. However, improper usage of … + READ MORE
    Phosphorus (P) is a vital nutrient for global agriculture, playing a pivotal role in crop germination and growth. However, improper usage of phosphorus can lead to detrimental effects on crops and significant environmental pollution. This study investigates the changes in available phosphate (P2O5) concentration in agricultural fields across 17 regions in South Korea from 2013 to 2020. During the study period, the total agricultural land area consistently decreased. Although rice paddy fields accounted for the largest proportion of the total agricultural area, the available P2O5 accumulation was the lowest due to low available P2O5 concentration. In contrast, soils within greenhouses accumulated excessive levels of available P2O5, significantly exceeding the recommended range. This underscores the importance of improved fertilizer management in greenhouses for the future sustainability of agriculture. Changes in available P2O5 accumulation (kg ha-1) under different types of agricultural land across 17 provinces (2013 - 2020). - COLLAPSE
    30 November 2023
  • Original research article

    Evaluation of Water Balance for Winter Crop (Forage Barley) Using Different Upland Soil Weighable Lysimeters
    Dong-hyun Kim, Seoung-oh Hur, Seon-ah Hwang, Bu-yeong Oh, Min-kyeong Park, Hyun-seo Yang, and Jung-hun Ok
    Due to recent climate change, various studies are needed to respond to water shortage in the agricultural sector. One of the important … + READ MORE
    Due to recent climate change, various studies are needed to respond to water shortage in the agricultural sector. One of the important factors for efficient water management is the quantification of evapotranspiration. In this study, water balances such as evapotranspiration and precipitation during growth of forage barley (Hordeum vulgare L.), a winter crop, were compared and analyzed using a weighable lysimeter, and crop coefficients and optimal water requirements for each growth stage were presented. Forage barley was cultivated repeatedly for three years in two soils with different soil textures. As a result of analyzing the water balance, there was no difference in the total inflow between two soil textures. The total outflow tended to be higher in the sandy loam soil, because the evapotranspiration was higher in the sandy loam soil which is better for crop growth. The crop coefficients by growth stage were 0.80, 1.00, 1.00, 1.30, and 1.17, respectively. As a result of estimating the optimal water requirement during the three-year cultivation period and comparing it with normal years, it was 15%, 7%, and 1% higher than normal years due to the low cumulative precipitation, and the water requirements were slightly higher than normal years. Accurate water balance evaluation and development of national factors in Korea using weighable lysimeter are expected to contribute to the estimation of the water management for upland crops in the future. Water balance for winter season crop (forage barley) in different upland soils by different water management methods. Year Water use NIR IR SiCL SL SiCL SL 2019 - 2020 Input (mm) Precipitation 254.0 254.0 254.0 254.0 Irrigation 8.7 8.6 9.0 8.7 Total 262.7 262.6 263.0 262.7 Output (mm) Drainage 94.4 0.5 87.6 60.7 Evapotranspiration 345.1 469.3 323.2 261.2 Runoff 1.6 3.1 2.5 12.7 Total 441.1 472.9 413.3 334.6 Changes in soil water (mm) -178.4 -210.3 -150.3 -71.9 2020 - 2021 Input (mm) Precipitation 231.5 231.5 231.5 231.5 Irrigation 9.3 9.4 9.4 9.1 Total 240.8 240.9 240.9 240.6 Output (mm) Drainage 56.3 1.4 23.7 21.6 Evapotranspiration 305.8 389.8 313.5 361.3 Total 352.1 391.2 337.2 382.9 Changes in soil water (mm) -121.2 -150.3 -96.2 -142.3 2021 - 2022 Input (mm) Precipitation 219.0 219.0 219.0 219.0 Irrigation 18.3 17.3 18.7 18.6 Total 237.3 236.3 237.7 237.6 Output (mm) Drainage 48.6 38.5 49.8 39.2 Evapotranspiration 293.5 330.3 302.5 387.1 Total 342.1 368.8 352.3 426.3 Changes in soil water (mm) -104.8 -132.5 -114.6 -188.7 NIR, non-irrigated after rooting stage; IR, irrigated by furrow irrigation. SiCL, silty clay loam; SL, sandy loam. - COLLAPSE
    30 November 2023
  • Original research article

    Effect of Biochar Derived from Greenhouse Crop Residue on Lettuce Growth and Soil Chemical Properties
    Dong-Won Lee, Yu Na Lee, Young Jae Jeong, Jin Ju Yun, Jae-Hong Shim, Sang-Ho Jeon, Yun-Hae Lee, Soon-Ik Kwon, and Seong-Heon Kim
    This study was conducted to evaluate the effect of biochar derived from greenhouse crop residues on the lettuce growth and soil chemical … + READ MORE
    This study was conducted to evaluate the effect of biochar derived from greenhouse crop residues on the lettuce growth and soil chemical properties in pot experiment. The pepper stem biochar was manufactured through a controlled pyrolysis process conducted at 400°C for a duration of 2 hours. Biochar application levels were conducted with 100, 200, 400, 800, 1,000, and 2,000 kg 10a-1 and the inorganic fertilizer (N-P-K 7.0-3.0-3.6 kg 10a-1) were applied on the recommended fertilizer application levels. The treatments were followed: no fertilizer (NF), inorganic fertilizer (NPK), biochar treatment without inorganic fertilizer (PB), biochar treatment with inorganic fertilizer (NPK+PB). The lettuce yields in the PB treatments were no significant difference in compared to the NF treatment. The lettuce yields in the NPK+PB treatments (2,589 kg 10a-1) were 111% higher than in the PB treatments (1,229 kg 10a-1). Also, the lettuce yields in NPK+PB100, NPK+PB200, NPK+PB400, NPK+PB800, NPK+PB1000, and NPK+PB2000 treatments increased by 104, 137, 125, 141, 141, and 144% respectively, compared to the NF treatment. The nitrogen uptake of the lettuce in the NPK+PB treatments (4.5 kg 10a-1) was 164% higher than in the PB treatments (1.7 kg 10a-1). After cultivation, the soil electrical conductivity (EC) and organic matter (OM) were affected by biochar application levels. Particularly, the soil chemical properties of NPK+PB2000 (1.3 dS m-1, 20 g kg-1) treatment was markedly increased compared with NF (0.7 dS m-1, 13 g kg-1) treatment. These results indicated that combined application of biochar and inorganic fertilizer can improve lettuce productivity and soil chemical properties. Greenhouse crop residues, Inorganic fertilizer, Lettuce productivity, Pepper stem biochar - COLLAPSE
    30 November 2023
  • Original research article

    Growth Enhancement of Tomato by a Plant Growth Promoting Bacterium, Bacillus subtilis PE7
    Seong Eun Han, Kil Sung Kim, Chaw Ei Htwe Maung, and Kil Yong Kim
    Bacillus species are well recognized as effective bio-stimulants to enhance crop quality and productivity. Our study demonstrates the effect of a plant … + READ MORE
    Bacillus species are well recognized as effective bio-stimulants to enhance crop quality and productivity. Our study demonstrates the effect of a plant growth promoting bacterium, Bacillus subtilis PE7 on tomato growth. In vitro screening assay for plant growth promoting traits indicated that the indole-3-acetic acid (IAA) production of B. subtilis PE7 in terms of increasing intensity of pink color with the increasing concentration of ⳑ-tryptophan supplemented in tryptone soy broth (TSB) medium. The supplementation of ⳑ-tryptophan (1 g L-1) in the TSB medium resulted in the maximum IAA production of strain PE7 with 25.59 µg mL-1 at 6 days after incubation. Moreover, the highest ammonia production of strain PE7 with 21.22 µg mL-1 was observed at an incubation period of 72 h. The results of our pot experiment revealed that treatment with the strain PE7 culture (inoculated in fertilizer-based medium) induced a significant growth promotion of tomato plants resulting in higher values of leaf number, length, fresh and dry weights of shoot as compared to the control and fertilizer treatment. Therefore, B. subtilis PE7 could be considered as an effective candidate for the development of eco-friendly commercial fertilizer in crop production. Growth promotion of tomato plants by Bacillus subtilis PE7 at 5 weeks after transplantation. *Con: water as control, F: fertilizer treatment, PE7: B. subtilis PE7 culture. - COLLAPSE
    30 November 2023
  • Original research article

    Assessment of Lettuce Yield and Soil Organic Carbon Fraction Distribution under Different Types of Organic Matter in South Korea
    Yu Na Lee, Dong-Won Lee, Young Jae Jeong, Jin Ju Yun, Jae-Hong Shim, Sang-Ho Jeon, Yun-Hae Lee, Soon-Ik Kwon, and Seong-Heon Kim
    In this study, we evaluated the effect of applying different types of organic matter on yield, soil chemical properties, and soil carbon … + READ MORE
    In this study, we evaluated the effect of applying different types of organic matter on yield, soil chemical properties, and soil carbon fraction in lettuce cultivation. The experiment consisted of six different fertilizations; no fertilizer (NF), inorganic fertilizer (IF), mixed expeller cake (MEC), mixed organic fertilizer (MOF), NPK+Cow manure compost (NPKCC), NPK+Pig manure compost (NPKPC). The yield of lettuce under NPKCC (2,962 kg 10a-1) was higher than NF (1,157 kg 10a-1), IF (1,990 kg 10a-1), MEC (2,173 kg 10a-1), MOF (2,398 kg 10a-1), and NPKPC (2,810 kg 10a-1). In the soil chemical analysis, the pH showed no significant difference between treatment, whereas both EC and available phosphate demonstrated statistically significant increases in response to the application of inorganic fertilizer and cow manure compost. The concentration of fulvic acid (FA) was high in the following order: NPKCC (776 mg kg-1) > MOF (684 mg kg-1) > NPKPC (652 mg kg-1) > MEC (623 mg kg-1) > IF (577 mg kg-1) ≒ NF (555 mg kg-1). The concentration of humic acid (HA) was high in the following order: NPKCC (1,868 mg kg-1) > NPKPC (1,403 mg kg-1) > MOF (1,346 mg kg-1) > MEC (1,304 mg kg-1) > IF (1,273 mg kg-1) > NF (1,206 mg kg-1). In conclusion, application of cow manure compost with inorganic fertilizer can increase lettuce yield and stable carbon (fulvic acid, humic acid) concentration. Therefore, it is recommendable for suitable soil management strategy to improve soil carbon and increase crop yield in upland soil. Furthermore, in order to provide a comprehensive evaluation of the enduring effects of organic matter application on crop yields, soil chemical properties, and soil organic carbon stocks, it is strongly recommended that further studies be undertaken. Effect of different organic matter on soil organic carbon fractions. - COLLAPSE
    30 November 2023
  • Original research article

    Numerical Approach for Air Temperature, Soil Temperature and the Difference between Them with Julian Date under Napa Cabbage
    Kicheol Eom
    The main objective of this study was to develop the estimation models for air temperature (Ta), soil temperature (Ts) at 15 cm … + READ MORE
    The main objective of this study was to develop the estimation models for air temperature (Ta), soil temperature (Ts) at 15 cm depth and the difference (dT = Ta - Ts) in Sandy Loam under Napa Cabbage cultivation. The verification process was based on the error analysis criteria. Results indicated a positive correlation between Ta and Ts, with higher Ta corresponding to higher Ts. The estimation models for Ta and Ts according to Julian date were developed as a log functions (log model for Ta, LMTa; log model for Ts, LMTs) judged 「Fit」 and 「Fit well」, respectively. The linear regressions for Ts and dT as the LRMTs (linear regression model for Ts) and LRMdT (linear regression model for dT) judged 「Fit」 and 「Unfit」, respectively. Furthermore, an analysis revealed that higher Ta, combined with lower water content, led to an increase in dT. A double regression model for dT, considering both Ta and Qv (double regression model for dT, DRMdT), was found to be a good fit for the dataset. In summary, this study successfully developed estimation models for Ta, Ts, and dT, employing both logarithmic and linear regression approaches. The models were rigorously evaluated using error analysis criteria, providing valuable insights into temperature dynamics in Sandy Loam during Napa Cabbage cultivation. Relationship between measured and estimated value by the DRMdT (double regression model for dT) for the difference (dT = Ta - Ts). - COLLAPSE
    30 November 2023
  • Original research article

    Effects of Rice Straw Return on Soil Labile Organic Carbon and β-Glucosidase Activity in Paddy Soil
    So-Hye Choi, So-Hui Kim, Jeong-Ah Jeong, Sang-Min Lee, and Cho-Rong Lee
    Rice straw is a source of organic matter (OM) that improves soil fertility. After rice straw is returned to the soil, increased … + READ MORE
    Rice straw is a source of organic matter (OM) that improves soil fertility. After rice straw is returned to the soil, increased microbial enzyme activity decomposes organic residues, affecting soil carbon. To evaluate the effects of continuous rice straw return on soil labile organic carbon (LOC) fraction and β-glucosidase (BG) activity in paddy soil, an experiment was conducted with four treatments; Chemical fertilizer treatment (NPK), Chemical fertilizer + rice straw treatment (NPKR), Green manure treatment (GM) and Green manure + rice straw treatment (GMR). Hot water extractable carbon (HWEC) content, permanganate oxidizable carbon (POXC) content, and BG activity were analyzed. HWEC content was 42% higher than in NPKR than in NPK. It was 8% higher in GMR than in GM, but there was no significant difference. In addition, POXC content was 17% higher in NPKR than in NPK. It was 11% higher than in GMR than in GM, but there was no significant difference. BG activity was 36% higher in NPKR than NPK, and 55% higher in GMR than GM. As a result, in paddy soil that are low in OM due to the predominant use of chemical fertilizers, rice straw return is likely to increase OM supply and LOC content in the soil and contribute to carbon cycling. Content of HWEC, POXC, and BG activity in paddy soil between NPK (chemical fertilizer treatment) and NPKR (chemical fertilizer + rice straw treatment). Vertical bars represent standard deviations (n = 3) and symbol * indicates significant difference at p ≤ 0.05. - COLLAPSE
    30 November 2023
  • Original research article

    Status and Changes in Chemical Properties of Orchard Soils in Gangwon State
    Byeong Sung Yoon, Soo Jeong Lim, Su Jeong Heo, Dong Min Kim, Kyungdae Kim, and Youngho Seo
    The chemical properties of orchard soils in Gangwon state have been monitored every 4 years from 2002 to 2022 in order to … + READ MORE
    The chemical properties of orchard soils in Gangwon state have been monitored every 4 years from 2002 to 2022 in order to provide basic information for orchard soil fertility management. In 2022, the soil chemical properties of orchard were 6.3 of pH, 0.82 dS m-1 of EC, 38 g kg-1 of organic matter (OM) and 803 mg kg-1 of available phosphate (Avail. P2O5). Exchangeable (Exch.) potassium (K), calcium (Ca) and magnesium (Mg) were 1.2, 7.2 and 2.0 cmolc kg-1, respectively. The distribution percentages within optimal range of pH were 43% in 2002, 30% in 2006, 45% in 2010, 41% in 2014, 39% in 2018, and 34% in 2022. The percentages for OM were 38% in 2002, 34% in 2006, 31% in 2010, 25% in 2014, 26% in 2018, and 29% in 2022. The excessive percentages for Avail. P2O5, Exch. Ca and Mg increased from 52% in 2002 to 71% in 2022, from 25% in 2002 to 55% in 2022, and from 19% in 2002 to 40% in 2022, respectively. In terms of heavy metals, mean contents of Cd and Hg were less than 5% of soil pollution standards (4 mg kg-1). Cu, Ni, Pb, and As were distributed to less than 20% of soil pollution standards. Therefore, it is necessary to fertilize based on soil test in order to maintain the soil chemical properties of the orchard soil within in an appropriate range. Excess, deficient, and optimal proportion of chemical properties of orchard soils in Gangwon state (n = 80). - COLLAPSE
    30 November 2023
  • Original research article

    Comparative Analysis of Microbial Community Characteristic of Acidic and Neutral Soils in Korean Orchards
    Do-Hyun Kim, Ji Yong Moon, Soo Young Hong, Hyeonmo Ahn, Yeo Wook Yoon, Hyo Jin Kim, So Youn Lee, Ji Won Kim, Eun-heui Han, Sang Yoon Kim, Eunjin Lee, Hang-Yeon Weon, and Ho-Jong Ju
    Soil microorganism is one of the most important factors in evaluating and improving soil quality because they play a crucial role in … + READ MORE
    Soil microorganism is one of the most important factors in evaluating and improving soil quality because they play a crucial role in the soil material circulation. They are closely correlated with soil environmental factors, and in particular, soil pH has a significant impact on the microbial community. This study aimed to examine the relationship between microbial communities and soil pH in orchard soil of the Republic of Korea. Microbial communities of 63 sites with neutral soil pH (pH 6 - 7) and 26 sites with acidic soil pH (pH 3 - 5) were analyzed targeting 16S rRNA and ITS genes through Illumina Miseq platform. Our analyses showed that bacterial richness and diversity and fungal richness in neutral soil were significantly higher than those in acidic soil (p < 0.001). According to PCoA and PERMANOVA, the microbial communities were significantly different in two soil groups, and ANCOM-BC showed high abundance of 16 bacterial and 15 fungal genera in neutral soil. Lastly, 9 genera, including Terrimonas, Povalibacter and Gp taxa, were identified as hub genera that have a significant impact on other microbial taxa in neutral soil. These results indicated that soil pH is a critical determinant of microbial communities and can serve as an indicator soil quality monitoring and evaluation. Network analysis to discover hub genera of bacteria (A) and fungi (B) in soil with two pH ranges. - COLLAPSE
    30 November 2023
  • Original research article

    Assessment of In-Season N Effects on Soil Water Stress to Growth and Yields of Soybean
    Dong Hyeok Gong, Sanghun Lee, Ki Yuol Jung, and Hyen Chung Chun
    In Korea, many farmers apply in-season nitrogen (N) fertilizer to increase yields, especially in case of paddy field cultivation. However, researchers are … + READ MORE
    In Korea, many farmers apply in-season nitrogen (N) fertilizer to increase yields, especially in case of paddy field cultivation. However, researchers are skeptical about positive effects of in-season N application to soybeans. Previous studies reported in-season N application helped increase of soybean yield and mitigate excessive soil moisture stress. Despite in-season N application affects soybean yields, there has been no extensive information regarding the effects of in-season N application. Therefore, this study investigated impacts of in-season N application to soybean growth and yields under various soil water conditions. Soybeans were planted and had the same amounts of basal N fertilizer for all pots. Soybeans were treated with isotopes (15N) as N particles for only pre-plant pots before sowing and in-season N particles at R1 growth stage. Soils had threes soil moisture conditions: drought (20%, v/v), control (25%, v/v) and waterlogging (30%, v/v). Growth and yield characteristics were measured after harvest. Amounts of 15N absorption in soybeans were analyzed. As a result, soybeans showed that soil moisture conditions affected growth characteristics, while in-season N application did not affect the growth characteristics. it is a reasonable result since in-season N applied after a vegetative stage. Yields from the control and waterlogging condition had the greatest yields with in-season N application. These were resulted from alleviate soil water stress effects and induced greater absorption of N in soybeans. Based on results of 15N absorption, water stress induced greater absorption of 15N to seeds and yield increase occurred from the control and waterlogging with in-season N application. These results can indicate that application of in-season N application may help to increase yields of soybean if soybean is not deficient to soil water. Diagram of 15N uptake ratio from soybean plant parts with or without in-season N application under different soil water conditions: Drought (20%, v/v), Control (25%, v/v), and Waterlogging (30%, v/v). Fertilizer treatments: PP (pre-plant) and INA (in-season N application). - COLLAPSE
    30 November 2023
  • Original research article

    Effect of Soil Moisture Conditions on Growth and Fruit Characteristics of ‘Bokjo’ Jujube (Ziziphus jujuba Mill.)
    Heesoon Park, Chae-Young Lee, Donggeun Lee, Hyo-Jung Kang, Ha-Kyung Oh, and Jong-Won Lee
    Soil moisture has an important effect on the growth of jujube (Ziziphus jujuba Mill.). Therefore, research on soil moisture must be … + READ MORE
    Soil moisture has an important effect on the growth of jujube (Ziziphus jujuba Mill.). Therefore, research on soil moisture must be conducted for stable growth and continuous production. Therefore, this study was conducted to determine whether soil moisture supply is necessary depending on the jujube growth period. The height, width, and cane diameter of jujube trees were found to be greater in the soil moisture -10 kPa treatment. The mineral content of leaves was high at -10 kPa for K, and the mineral content of fruit after harvest was high at -10 kPa for N, P, and Ca. And fruit yields were higher in the soil moisture -10 kPa treatment, especially large fruits exceeding 30 mm in diameter. The length, width and weight of the fruit were high at -10 kPa, but the soluble solid content was high at -30 kPa. Therefore for stable fruit production of jujube, soil moisture of -10 kPa is required during the flowering and fruiting stages and fruit enlargement stage, and in order to produce jujube fruit with high sugar content, the irrigation amount must be reduced to -30 kPa before harvest. Fruit quality characteristics after jujube harvest. - COLLAPSE
    30 November 2023
  • Original research article

    Analysis of Soil Characteristics and Inter-Annual Variability for Rice Yield Distribution with Grid System for Precision Agriculture
    Kyung­Do Lee, Sook-Gyeong Kim, Tae-Gon Kim, Yeon-Kyu Sonn, Woo-Ri Go, Jae-Hyun Ryu, and Ho-Yong Ahn
    Precision agriculture relies on the uniformity of location-based agricultural environmental data, such as soil, weather, and sensing. In this study, we propose … + READ MORE
    Precision agriculture relies on the uniformity of location-based agricultural environmental data, such as soil, weather, and sensing. In this study, we propose a grid system for precision agriculture to data spatial alignment. Based on this precision agriculture grid system, we analyzed the spatial distribution variability of annual soil chemical components and estimated rice yield distribution based on these components. The results from the years 2018 and 2019 showed that the average values of soil chemical components in non-paved areas exhibited no significant differences. However, even with the similarity in average soil chemical component values, we confirmed through spatial distribution maps that there can be diverse and biased distributions within the soil, as well as inter-annual variations. In the process of estimating rice yield using soil chemical components, the Random Forest model showed higher explanatory power and accuracy compared to the multivariate linear regression model. Both models, however, incorporated a wide range of chemical characteristics as model variables, beyond the key variables typically used in traditional rice fertilizer estimation. This diversity in model variables is presumed to be a result of the unique agricultural environment, such as uneven use of additional fertilizer. Therefore, it is crucial to emphasize that, even after calculating crop fertilizer quantities through soil analysis, stable yield and quality assurance require precision agriculture management based on crop growth monitoring. Estimation map of rice yield distribution using soil chemistry by model. - COLLAPSE
    30 November 2023
  • Original research article

    Yield of Kimchi Cabbage and Soil Chemical Properties Following Slow Released Fertilizer Use in the Highlands of Gangwon
    Yang-Min Kim, Mavis Badu Brempong, Gye-Ryeong Bak, and Jeong-Tae Lee
    Fertilizer application is a major Kimchi cabbage production factor, which has been adopted historically to increase yields. However, conventional fertilizer (CF) use … + READ MORE
    Fertilizer application is a major Kimchi cabbage production factor, which has been adopted historically to increase yields. However, conventional fertilizer (CF) use is associated with severe environmental concerns due to its nutrient release pattern and nutrient loss potential. Split applications of CF during the cultivation period also incurs extra labour costs. Slow release fertilizer (SRF),on the other hand, is applied one-time, hence it does not require extra labour, as it slowly releases nutrients over a span of time allowing nutrient release to synchronize with critical crop nutrient demand periods. It has been suggested as an alternative to CF to curb the environmental menace. In our study, we compared the effect of CF and SRF on soil nitrogen (N) dynamics, Kimchi cabbage yield and residual soil chemical properties in the growing seasons of 2021 and 2022 at the Highland Agriculture Research Institute in the Gangwon State Government, under rain-fed conditions. The CF resulted in high soil NH4+ and NO3- concentrations during the last period of cultivation, however, SRF showed a slow increase pattern of the nutrients up to the middle of the cultivation period and then a decrease till the harvest time. Kimchi cabbage yields were similar under CF and SRF in 2021 (43 and 48 Mg ha-1 respectively) and 2022 (81 and 79 Mg ha-1 respectively). The CF left the highest residual soil NH4+ and NO3- concentrations in 2021 (12 and 24 mg kg-1) and 2022 (24 and 22 mg kg-1). Considering that similar yields were affected by CF and SRF, it could be inferred that more soil N from CF were subject to losses and potential environmental concerns, as CF affected higher soil N concentrations during the growing seasons and after harvest. Holding all other crop production factors constant, SRF has an advantage over CF in terms of saving labour costs and potentially protecting the environment. Changes in soil NH4-N and NO3-N concentrations in response to conventional fertilizer (CF), slow release fertilizer (SRF) and no fertilizer control in the year 2022. - COLLAPSE
    30 November 2023
  • Original research article

    Physiological Responses and Nitrogen Use Efficiency of Cereal Crops, Barley and Oat, in the Reclaimed Soil
    Min-Chang Kim, Ga-Eun Kim, Min-Ji Kim, Bo-Youn Lee, Hyeoun-Suk Cho, and Jwakyung Sung
    Soil salinization, particularly agricultural lands, is a significant limiting factor to threat the growth and production of economically important cereal crops. The … + READ MORE
    Soil salinization, particularly agricultural lands, is a significant limiting factor to threat the growth and production of economically important cereal crops. The reclaimed agricultural lands in South Korea accounts for approximately 7.1% (112,464 ha), and, of those, the Saemangeum reclaimed land is under construction as a scale of 8,570 ha. The goal of this study is to extend our knowledge through understanding the interactions among growth and production, osmo-protectants and NUE from selected barley and oats varieties. Barley (Hordeum vulgare cv. Jaeanchal, Sogang) and oat (Avena sativa cv. Daeyang, Joyang) with RDA crop cultivation manual were tested in the reclaimed experiment field of National Institute of Crop Sciences (NICS), Gimje, Jeonbuk province from late March to late June, 2023. In barley, biomass production, mineral nutrients and soluble sugars were not different, while spike yield was 1.4 times-higher in Sogang compared to Jaeanchal. Total proline was significant higher in Jaeanchal, however, its level revealed tissue-specific difference; higher in root and spike (Jaeanchal) and in shoot (Sogang). Nitrogen use efficiency (NUE) was positively affected by spike yield, indicating that Sogang was greater NUE than Jaeanchal. In oat, biomass production and spike yield were 1.4 times-higher in Joyang compared to Daeyang, whereas proline and soluble sugars were abundantly accumulated in Joyang. NUE also was higher in Joyang due to greater biomass production including spike yield. Overall, it was concluded that greater spike yield-producing variety revealed higher NUE and lower osmo-protectants levels, and these results imply that the reclaimed soil condition ‘Saemangeum’ might be not a big limitation for barley and oat cultivation with an employment of an appropriate nutrient management if soil physical properties could be amended. Correlation between variables at harvest stage in barley (Jaeanchal, Sogang) and oat (Daeyang, Joyang) grown in the reclaimed soil (Saemangeum) at harvesting stage. - COLLAPSE
    30 November 2023
  • Short communication

    Correlation between Soil Chemical Properties and Plant Mineral Elements for Nutrient Management of Mulberry (Morus alba L.)
    Yosung Song, Chanwook Lee, Hyejin Park, and Yejin Lee
    The nutrition management manual for mulberry trees is designed for leaf production in Korea. For fruit production of mulberry, a separate manual … + READ MORE
    The nutrition management manual for mulberry trees is designed for leaf production in Korea. For fruit production of mulberry, a separate manual is necessary because fruit yields are influenced by vegetative growth. In this study, we conducted a correlation analysis between soil chemical properties and the mineral content of both leaves and fruits of mulberry trees to identify factors for effective nutrition management in mulberry trees for fruit production. We surveyed 39 mulberry farms in Buan, Jeollabuk-do, where mulberry trees had been cultivated for over 10 years. Soil, leaves, and fruits of mulberry were sampled in mid-May. The average fertilization rates for mulberry were N-P2O5-K2O = 143-70-77 kg ha-1. The average of soil pH, organic matter, and available P2O5 was within the optimal range for orchard soils, but the exchangeable cations exceeded the recommended levels. Correlations were observed between NPK fertilization, soil organic matter, and the nitrogen content of leaves. The nitrogen content of leaves showed correlations with nitrogen, phosphorus, potassium, and magnesium content in the fruits. While fruit yields were not directly correlated with the nitrogen content of leaves, trees with a nitrogen content above 3.5% exhibited higher average yields and nitrogen content in their fruits compared to trees with less than 3.5% nitrogen content in leaves. Based on these results, the nitrogen content of leaves was useful for diagnosing the nitrogen status of mulberry trees. Further studies are required to explore the relation between nitrogen content in leaves, fruit quality concerning nitrogen fertilizer amounts, and soil organic matter. Correlation between mineral nutrient contents of Mulberry and fertilizer use and soil chemical properties (n = 39). Fertilizer use Soil chemical properties N Fert. P Fert. K Fert. pH EC SOM T-N NO3-N Av. P2O5 Ex. K Ex. Ca Ex. Mg K/Ca+Mg Fruit yields 0.014 0.064 -0.205 -0.066 -0.036 0.033 -0.057 0.079 -0.090 -0.096 0.034 0.102 -0.165 Leaf N 0.443* 0.396* 0.349* -0.078 0.148 0.334* 0.189 0.233 0.100 0.101 -0.119 0.158 0.127 P 0.233 0.258 0.231 -0.212 0.025 -0.100 -0.120 0.161 -0.011 -0.168 -0.244 -0.378* -0.099 K -0.184 -0.198 -0.265 0.055 0.229 0.092 0.095 0.065 0.258 0.331* 0.180 -0.079 0.295 Ca -0.283 -0.319 -0.341 0.454* 0.133 -0.063 0.057 0.200 -0.113 -0.136 0.414* 0.109 -0.318* Mg -0.005 -0.065 0.037 0.122 0.082 -0.046 -0.067 0.024 -0.063 -0.076 0.001 0.016 -0.084 Fruit N 0.319 0.274 0.257 0.039 0.329* 0.346* 0.446* 0.373* 0.361* 0.131 0.043 0.102 0.106 P 0.361* 0.339* 0.325 -0.047 0.230 0.172 0.312 0.201 0.398* 0.088 -0.124 -0.031 0.145 K 0.236 0.206 0.202 -0.034 0.352* 0.425* 0.432* 0.266 0.534* 0.256 0.055 0.024 0.257 Ca -0.317 -0.314 -0.289 0.206 -0.073 0.144 0.065 -0.248 0.129 0.075 -0.044 0.107 0.104 Mg -0.020 -0.021 -0.032 -0.065 0.042 0.383* 0.386* -0.103 0.332* 0.246 -0.125 0.099 0.325* Pearson correlation coefficients, *p < 0.05. - COLLAPSE
    30 November 2023
  • Short communication

    Evaluation of Crop Growth and Soil Chemical Properties in Cadmium Contaminated Soil Using Biochar Derived from Rendered Animal Carcass Residues
    Jin Ju Yun, Dong-Won Lee, Jae-Hong Shim, Sang-Ho Jeon, Yun-Hae Lee, Soon-Ik Kwon, Jong-Hwan Park, Se-won Kang, Ju Sik Cho, and Seong-Heon Kim
    Rendering process is known as a quick and stable method that copes with dead livestock by extracting and purifying the animal’s fat … + READ MORE
    Rendering process is known as a quick and stable method that copes with dead livestock by extracting and purifying the animal’s fat and others through the heat treatment at high temperature and with high pressure. However, a large amount of solid byproducts equivalent to 15% of the weight of carcasses after this process are discharged, and some of them are provided as livestock feed and compost, but others are landfilled since the processed byproducts must go through the secondary process again. It is judge that RACR (rendering animal carcass residue) has a high utilization value since it is composed of protein and bone tissues and a very high domestic applicability as it can secure a rich amount of it. Therefore, in this study, the effects of biochar derived from rendered animal carcass residues were evaluation on crop growth characteristics and soil chemical properties in cadmium contaminated soil. The results of pot experiment showed the process with RACR-C (rendering animal carcass residue biochar) had the effect of soil amendment that increased the pH, organic content, available phosphate, and cation exchange capacity in the contaminated soil. In addition, the analysis of phyto-availability of cadmium by 1 M NH4NO3 sampling method showed there was an effect of reducing cadmium transfer by 26 to 98% depending on the amount of processed biochar compared to the untreated control plot and also effective in promoting the growth of radish, such as fresh weight, leaf number. Thus, it is judged that the biochar produced with the rendering animal carcass residue biochar can be applicable as a soil stabilizer during the process of cadmium-contaminated soil, and eco-friendly and economically efficient in terms of waste resource recycling. Phytoavailability of Cd by 1 M NH4NO3 extraction in soil after plant harvest. - COLLAPSE
    30 November 2023
  • Short communication

    Site Selection for Centralization of Pig Manure Biogas Facilities in Gyeonggi-do Using Kernel Density Analysis
    Eunhee Choi, Jae-Jak Nam, and Seungheon Lee
    In South Korea, the standard facility capacity for bioenergy facilities is set at 100 tons per day based on livestock manure amount … + READ MORE
    In South Korea, the standard facility capacity for bioenergy facilities is set at 100 tons per day based on livestock manure amount by bioenergy-related laws. To achieve the government’s goals for the energy recovery from livestock manure, there is a need to expand and distribute centralized facilities with a capacity of 100 tons of livestock manure per day. The location and scale of these centralized facilities are influenced by the geographical location and livestock breeding scale of nearby livestock farms. The size of most domestic pig farms is small, thus it is necessary to analyze the distribution and density of medium-sized or larger livestock farms capable of supplying manure to centralized facilities. In this study, kernel density analysis and spatial density analysis were conducted to select suitable regions for centralized biogas facilities for pig manure for Gyeonggi-do. As a result of analyzing the Gyeonggi-do region as a case study, four regions in southern Gyeonggi-do and one region in northern Gyeonggi-do were estimated to be suitable regions. Although it is necessary to confirm specific suitable regions through a feasibility assessment of regions estimated to be suitable regions, it is believed that selecting candidate regions first and conducting a feasibility study through kernel density analysis will save time and help in rational decision-making. Kernel density analysis for pig breeding farms between 10,000 to 20,000 pigs. - COLLAPSE
    30 November 2023
  • Review

    North Korea’s Shift to Organic Farming and the Role of Microbial and Organic Fertilizers
    Sanghun Lee, Jeongsup Song, Sook-Young Park, Eun Young Kim, and Yangseon Kim
    Sustainable agricultural practices have become globally important. This trend is linked to growing concerns regarding environmental degradation, resource scarcity, and food security. … + READ MORE
    Sustainable agricultural practices have become globally important. This trend is linked to growing concerns regarding environmental degradation, resource scarcity, and food security. This review explores the transition of North Korea to organic farming and highlights how microbial and organic fertilizers have been integral in facilitating this process. The primary source of information that underlies this review was studies conducted in North Korea. As a country that has faced a wide range of socioeconomic crises over the past few decades, including those directly impacting food security, North Korea has been exploring options to improve soil health and enhance crop production. To address these issues, North Korea has adopted organic farming practices. Alongside organic farming, efforts are underway to enhance crop productivity by implementing programs that monitor and prevent pathogen and pest infestations. Overall, the cornerstone of North Korea’s organic farming model is the “Circular Closed-Loop Production System” which is largely rooted in self-sustaining agricultural cycles. These cycles include integrating crop cultivation and livestock production systems with multiple components. In conclusion, the progress North Korea has made in its implementation of organic farming practices highlights the feasibility of using organic and microbial fertilizers to address agricultural challenges and promote sustainable agriculture. North Korea’s organic farming system. - COLLAPSE
    30 November 2023
  • Review

    A Review on International Carbon Credit Certification Methodologies for Biochar as a Soil Amendment
    Kyung-Hwa Han, Seok-In Yun, Jin-Hyeob Kwak, and Sun-Il Lee
    The high organic carbon (Corg) sequestration ability of biochar can greatly contribute to atmospheric CO2 removal for global C … + READ MORE
    The high organic carbon (Corg) sequestration ability of biochar can greatly contribute to atmospheric CO2 removal for global C neutrality. These climate-positive services of biochar are traded as C credits on international C trading platforms through reliable methodologies. Here, we reviewed the international biochar C credit certification methodologies and quality standards to build foundations for biochar C credit trading in Korea. The quality of biochar includes the quantity of Corg sequestered over 100 years, the content of toxic contaminants below their threshold values, and the biochar properties related to soil fertility, as described by European Biochar Certificate (EBC) and International Biochar Initiative (IBI) certification guidelines. The higher amount of Corg sequestered over 100-year in biochar is ascribed to the lower the molar H/Corg and O/Corg ratios, resulting from pyrolysis of feedstock at a high temperature over 350°C. For assuring the permanence of biochar, the threshold value of molar H/Corg ratio is 0.7 in both EBC and IBI. Besides, EBC standards also have the threshold value 0.4 of a molar O/Corg ratio for all biomass and require a pyrolysis condition of exceeding 500°C for 3 min at minimum for animal-derived biomass. Quality-certified biochar can be used for C credits. Biochar C credit is the amount of net CO2-eq removed over 100-year by the biochar activity, i.e., biochar Corg sequestered over 100-year minus greenhouse gas (GHG) emissions over the biochar life cycle. The three voluntary C credit trade platforms with their own biochar methodologies are Puro.earth with life cycle assessment, Carbonfuture with C-sink certification, and Verra with UNFCCC Clean development mechanism (CDM) methodology. All three methodologies present standards for permissible biomass for feedstock, energy efficiency and by-product treatment for production, permissible matrices and tracking system for end use, and the third-party verrification. On a regional basis in Korea, where biochar feedstock is mainly biogenic waste, GHG emissions during biochar lifetime mainly depend on the production stage. In pyrolysis facilities that meet EBC and Verra’s high-tech standards, GHG emissions during the production stage could be assumed to be very low. However, low-tech facilities with high GHG emissions during biochar production could deteriorate biochar C credits. Therefore, securing biochar C credits could be achieved through the modernization of pyrolysis facilities. Besides, it is essential to establish a process-oriented measurement, reporting, and verification systems, to ensure scientific reliability of biochar C credit certification. Calculation methods for biochar carbon (C) credits called CORC, C-sink, and VCU used in voluntary C credit trade platforms, Puro.earth, Carbonfuture, and Verra, respectively. C credit trade platform C credit calculation methods (tCO2eq) Comments Puro.earth • CORC = Estored - Ebiomass - Eproduction - Euse • Estored = Qbiochar × Corg × FpTH,Ts × 44/12 • Qbiochar is the amount of biochar produced over the reporting period; Corg is the organic C content of the biochar produced; FpTH,Ts = c + m × H/Corg is the permanence factor of biochar organic C over a given time horizon TH in a given soil at temperature Ts, where the coefficients c and m are a function of TH and Ts • Estored: CO2 sequestered over 100 years • Ebiomass, Eproduction, Euse: Life cycle GHG during each stage Carbonfuture • C-sink is determined by integrating C-sink potential, greenhouse gas emissions (GHG) during C-sink tracking after leaving factory gate, and C remaining % after 100 y in applied matrix • C-sink potential = Corg content of biochar - GHG during biomass sourcing - GHG during production - Safety margin • Safety margin = 10% of the total GHG emission of biomass sourcing and production • EBC C-sink standard requires that the biochar may only be used in specific ways Verra Overall equation • VCU = ERPS,y - PEAS,y - LEy, in year y • ERPS,y = GHG emission removals at production; PEAS,y = GHG emissions at application; LEy = Total leakage emissions, primarily attributed to transport emissions • ERPS,y = ∑((∑CCt,k,y × 44/12) - (∑PEPS,t,p,y)) • CCt,k,y = Organic carbon content, sequestered over 100 years, on a dry weight basis for biochar type t used for application type k; PEPS,t,p,y = Project GHG for production of biochar type t at production facility p may arise from pretreatment like drying wet waste, thermodynamic conversion, or use of external energy • GHG reduction at the sourcing stage is zero following a conservative scenario • GHG by transport must be accounted for only if the distance is more than 200 km in round trip High tech. production • Thermodynamic conversion emissions are zero and renewable energy use reduces GHG Low tech. production • Thermodynamic conversion includes CH4 emissions, which can be obtained using estimation equation • GHG for the pretreatment and use of external energy can be obtained using CDM Tool 05 (UNFCCC, 2008a) and CDM Tool 03 (UNFCCC, 2008b) - COLLAPSE
    30 November 2023