Background : The fungus Cylindrocarpon destructans (Zins) Scholten is the cause of root rot in many ginseng production areas. Root exudate composition and quantity vary in relation to plant nutritional status, but the impact of the differences on rhizosphere microbial communities is not known. Methods and Results : Five kinds of rotation crops, sudan grass soybean peanut sweet potato, perilla were grown for one year in ginseng garden harvested 6-year-old ginseng. The ratio of gram-negative bacteria, fungi, bacteria, total microbial biomass, aerobic/anaerobic microbes were increased by rotational crop cultivation, while the ratio of actinomycetes and the ratio of saturated to unsaturated fatty acids were decreased. The increase in the fungal density or the increase in the proportion of fungi to the bacteria tended to increase the incidence of root rot, but there was no significant difference. The yield of ginseng root showed a highly significant negative correlation with actinomycetes. The correlation between the soil chemical properties and the incidence of root rot was analyzed by cultivating 23 kinds of green manure crops for one year in field where cultivated ginseng continuously. The survival rate of ginseng showed a highly significant positive correlation with soil acidity and a highly significant negative correlation with nitrate nitrogen, and a significant negative correlation with soil salt concentration. Conclusion : Rotation crops improved soil microbial communities, lowered the rate of fungi and increased the proportion of bacteria, the survival rate of ginseng was significantly correlated with soil acidity, nitrate nitrogen and soil salinity.

농촌진흥청에서 고시하고 있는 비료공정규격에 따르면 퇴비의 적정 염분은 2% 미만으로 규정하고 있으며 이 기준은 일반퇴비 및 음식물류폐기물퇴비(이하 음식물퇴비) 구분없이 동일한 기준이 제시되고 있다. 실제 농가에서는 음식물퇴비 내 염분이 높다는 편견이 있어 작물을 키우는데 음식물퇴비를 사용할 경우 작물이 죽거나 잘 자라지 않는 등의 의식이 팽배하여 작물재배 및 농가에서 음식물퇴비의 사용량이 저조하며 의식이 부정적인 상황이다. 따라서 본 연구에서는 음식물퇴비의 염농도, 혼합율에 따른 작물재배 실험을 진행하였으며 작물 재배 시 염분농도에 따라 작물이 받는 영향에 대해 알아보고자 하였으며 토양의 염분농도, 음식물퇴비의 염분농도, 토양과 음식물퇴비의 혼합율에 따라 작물의 발아율, 성장정도의 변화를 살펴보고자 하였다. 실험은 토양별 염분농도, 음식물퇴비의 염분농도, 토양과 음식물퇴비의 혼합율, 총 3가지 조건에 변화를 주어 실험을 진행하였다. 실험은 총 5일주기로 각 작물의 발아율, 성장정도, 토양 내 염분농도를 측정하였으며 염분농도의 유실량 및 작물로의 흡수량을 보기위해 염분농도 측정 대조군을 측정용으로 설정하였다. 첫 번째 실험은 토양 염도가 작물에 끼치는 영향을 알아보기 위해 토양 내 염분농도를 각각 0.5%, 1.0%, 1.5%, 1.7%, 2.0%, 2.2%, 2.5%로 조절하여 작물 재배 실험을 진행하였다. 두 번째 실험은 토양에 혼합하는 음식물퇴비의 염분이 작물에 끼치는 영향을 알아보기 위해 토양과 음식물퇴비를 20:1로 혼합하였으며 혼합하는 음식물퇴비에 염분농도를 1%, 2%, 3%, 4%, 5%로 추가 조절하여 작물 재배 실험을 진행 하였다. 세 번째 실험은 음식물퇴비와 토양의 혼합율이 작물에 끼치는 영향을 알아보기 위해 토양과 음식물퇴비의 혼합비를 각각 1%, 3%, 5%, 10%로 조절하여 작물재배 실험을 진행하였다. 실험 결과 음식물 퇴비의 혼합 없이 토양의 염도를 추가해준 경우, 작물이 재배될 수 있는 최대 염분농도는 2.0% 미만으로 측정되었으며, 토양 내 혼합하는 음식물퇴비의 적정염도는 5% 이하에서 가장 높은 효율을 나타냈다. 음식물퇴비를 사용하여 작물을 재배 할 시 일반적으로 혼합되는 비율인 20:1로 혼합하였을 경우 음식물퇴비의 적정 염도는 5%로 확인되었다. 이는 시중에서 판매하는 음식물 퇴비보다 1%높은 염분농도임을 확인하였다. 이는 음식물퇴비의 혼합비율은 작물의 발아율에 부정적인 영향을 주지 않는다는 것으로 판단되며 음식물퇴비를 이용하여 작물 재배를 하였을 시 기존보다 우수한 발아율 및 성장정도를 나타내는 것으로 보인다.

물은 22.1 MPa의 압력하에 100℃ - 374℃의 온도범위에서 액체상태로 존재하며, 이를 아임계수라 한다. 아임계수 조건에서 물은 분자간 수소결합이 약해지면서 유전상수, 점성, 표면장력이 감소되어 유기용매와 유사한 특성을 지니게 된다. 원유오염토양은 전남 여수지역 공단 내에 있는 유류로 오염된 토양을 이용하였으며, 오염기간은 약 1년이며 저분자성 휘발유류성분 및 고분자성 유류로 오염되어 있었다. 초기 오염된 TPH농도는 16,895 mg/kg였다. 원유오염토양은 고분자성 물질이 다량 함유되어 있어 기존정화방법으로는 처리하기 어려운 점이 있다. 이를 해결하기 위하여 상기 아임계수 특성을 이용하여 원유로 오염된 토양으로부터 오염물질을 추출하는 연구를 수행하였다. 이와 함께 친유성 용매인 등유를 이용하여 토양으로부터 원유 일부를 탈착(전처리)시킨 후, 아임계수로 토양 내에 잔류되어 있는 유류성분을 제거하는 실험도 수행하였다. 이를 통해 아임계수 추출만을 적용하였을 경우와 등유 전처리가 추가된 경우의 제거율과 정화공정상 효율을 비교하였다. 아임계수 추출 시 275℃에서 2시간 추출을 5회 반복 진행하였을 때, 토양 내의 잔류 유류 농도가 498 mg/kg(제거율 97%)로 나타났다. 등유 전처리(토양 : 등유=1 : 0.5 wt%)후 아임계수 적용시 250℃에서 1시간동안 추출 시, 토양 내 잔류 유류 농도는 223 mg/kg로 나타났다. 적용된 두가지 공정 모두 토양1지역 우려기준(500mg/kg)이하로 정화되었으나, 상대적으로 등유전처리가 포함된 공정이 아임계수 기술만을 적용하여 추출을 진행한 것보다 상대적으로 높은 제거율을 보였다. 또한 등유 전처리가 추가된 아임계 공정이 추출시간, 공정수, 투입에너지(가열)에 있어 경제적으로 판단되며, 따라서 원유 오염토양의 아임계수 정화공정에서는 등유전처리 도입이 효과적인 것으로 판단된다.

국내에서 토양 내 중금속 농도를 정량하기 위하여 다양한 분석장비 및 전처리관련 공정시험법이 존재한다. 대표적으로 환경부 토양환경공정시험법에서는 토양의 전분해(왕수추출)후 AAS 또는 ICP로 분석을 제시하고 있으며, 해양환경공정시험법에서는 퇴적물의 완전분해 후 분석이 제시되어 있다. 또한, 상기 화학적 전처리공정을 거치지 않는 XRD분석이나 입자를 레이저빔으로 승화시켜 측정하는 레이저 유도 붕괴 분광법(LIBS; Laser-Induced Breakdown Spectroscopy)도 상용화 되고 있다. 이러한 각종 전처리 및 분석 방법은 특히 전처리 정도에 따라 동일시료라 하더라도 경우에 따라 측정된 농도 값에 차이가 발생되나, 신기술이나 검증 등에 고려하지 않는 경우가 많기 때문에 혼란이 야기되는 실정이다. 따라서, 토양시료를 대상으로 전처리에 따른 분석결과차이를 증명하고, 이를 상용화 중인 LIBS분석방법과 비교하고자 한다. 중금속 오염토양 10가지를 대상으로 하였으며, 각 토양을 왕수분해(전분해)하고 충분히 반응시키고 원심분리하여 상등액을 분취하여 분석시료로 하였다. 이 왕수추출 후 잔류입자 내 잔류 중금속 농도를 정량하기 위하여 불산 등을 투입(완전분해)하여 잔류입자를 완전히 용해시켜 이를 분석시료로 하였다. 전분해와 완전분해는 각각 토양오염공정시험법과 해양환경공정시험법(-퇴적물)을 바탕으로 실험하였다. 중금속 농도 정량에는 ICP-OES(Perkin Elmer DV2100)을 사용하였으며, 총 5종(납, 아연, 구리, 크롬, 카드뮴)을 분석하였다. 추가로 동일 토양시료를 레이저유도 붕괴 분광법(LIBS)으로도 분석하여 이를 비교해 보았다. 토양시료 10개에서 납, 아연, 구리, 크롬의 분석농도는 완전분해(불산 등)대비 왕수분해(전분해)가 65~100%, 62~94%, 71~91%, 30~52%로 나타났으며, 이때 카드뮴은 검출되지 않았다. 토양 왕수추출 후에도 잔류입자(주로 실리카)에 중금속이 일부 존재하고 있는 것으로 나타났으며, 이는 전처리 후 입자유무에 따라 토양 에서 잔류중금속 농도 분석 값이 다를 수 있음을 나타낸다. 완전분해 시 납, 구리, 크롬, 아연 농도는 LIBS측정치 대비 평균회수율이 각각 87.8, 96.8%, 106.2%, 90.1%로 나타나 상대적으로 LIBS방법과 유사한 측정결과가 나타났다. 이는 완전분해 측정법과 LIBS측정법이 입자까지 모두 용해 또는 승화시켜 측정하는 방법이라는 점에서 유사하기 때문으로 판단된다.

런던협약에 의해 2015년부터 폐기물 해양투기가 전면 금지됨에 따라 국내 광물자원 관련 산업체에서는 폐기물의 처리 방안 마련이 요구되고 있다. 알루미늄 생산 공정에서 보크사이트 부산물은 연간 27만 톤 가량 발생하고 있으며 대부분 토목공사 성토용 골재로 재활용되고 있으나, 전량 골재로 활용이 어려워 매년 8만 톤 이상적치되고 있는 실정이다. 우리나라 농경지는 하절기 집중호우, 화학비료 다량 사용 등으로 토양의 산성화가 가속화되고 있어 농작물 생육조건에 적합한 pH 유지를 위해 주기적인 토양 개량이 필요하다. 보크사이트 부산물을 활용한 토양개량제가 석회(Ca), 고토(Mg)를 대체하여 산성토양 개량제로 재활용 가능성에 대하여 연구하고자 한다. 보크사이트 부산물을 토양개량제로 활용함으로써 매립 등에 소요되는 처리비용을 절감하고 자원순환 측면에서 폐기물제로화(waste zero)에 크게 기여할 것이다. 보크사이트 부산물의 위해성 여부를 확인하기 위해 ｢토양환경보전법｣ 토양오염 우려기준에서 정하고 있는 중금속 8종 물질의 분석 결과 불검출 또는 기준치 이하로 검출됨을 확인하였다. 전남 나주시 금천면 석곡리 일원(임야와 농경지 연접부)에서 pH 4.9 ~ 5.0 범위의 토양을 채취하여 샘플 토양으로 사용하였으며 채취한 샘플산성토양에 보크사이트 부산물 과립 개량제를 1~10%(wt) 범위로 혼입하여 pH 변화를 조사하였다. 이때 농경지에서 경운, 강우에 의한 수화반응 등을 적용하고자 일정 기일간 양생을 거친후 pH를 측정하였다. 증류수(토양의 25%)와 5일간 양생 반응 후 측정한 결과 토양개량제 1%를 혼입한 시료에서는 pH 7.5 ~ 8.0, 10% 혼입시료는 pH 9.0 ~ 9.5 범위로 나타났다. 보크사이트 부산물을 토양개량제로 활용 시 중금속류에 의한 오염은 없을 것으로 사료되며 보크사이트 부산물이 경작 작토부 토양의 1% 이내로 살포할 경우 산성토양 중화에 적합할 것으로 판단된다.

This study was performed to develop the efficient phytoremediation model in the paddy soil contaminated with heavy metals by cultivating Pteris multifida and Artemisia princeps with different mixing ratios (1:0, 8:1, 6:1, 4:1). As a result of investigating the heavy metal accumulation of each plant per dried material (1 ㎏), content of arsenic and cadmium was the highest in aerial part of P. multifida (169.82, 1.70 ㎎·㎏-1 DW, each) among the treated group. Lead content was the highest (12.58 ㎎·㎏-1 DW) in the aerial part of P. multifida cultivated with 8:1 mixed planting. But the content of copper and zinc was the highest (33.94, 61.78 ㎎·㎏-1 DW, each) in the aerial part of A. princeps with 8:1 treatment. Regardless of heavy metals, plant uptake from the 1 ㎡ soil was the highest in 4:1 mixed planting group, which showed the best yield of A. princeps.

Background:The study aimed to obtain data on the effects of cultivation and soil reduction of green manure crop on the quantity and quality of organically cultivated Cynanchum wilfordii Hemsley.Methods and Results:The experiment comprised four treatments: control, hairy vetch, barley, and hairy vetch + barley (3 : 2). The plant height in the hairy vetch treatment (86.3㎝) was significantly different from that in the other treatments, whereas the stem diameter leaf area, and special product analysis division (SPAD) value did not differ across the treatments. The largest soil reduction of green manure crop was recorded in the barley treatment (440 ㎏/10 a), whereas the smallest was recorded in the single treatment with hairy vetch (80 ㎏/10 a). The hairy vetch + barley (60 : 40) treatment showed 63% more soil microorganisms than control. Radical scavenging activity estimation revealed that the total polyphenol content was highest (1,740 ㎎/㎏), and the 2,2-diphenyl-1-picrylhydrazyl (DPPH) was 92.6% in the barley treatment. The 2,2’-azino-bis-(3-ethylbenzothiazoline-6-sulfonic acid) (ABTS) activation was highest in the control (51.1%), and the root yield was the highest in the barley treatment (310 ㎏/10 a).Conclusions:The root yield, total polyphenol content, and antioxidant activity of Cynanchum wilfordii (Maxim.) Hemsley increased in presence of the green manure crop barley.

본 연구는 유기농경지의 지속가능한 토양양분관리를 위해 유기농가의 자재의존도와 자 재에 의한 토양 특성변화를 알아보기 위하여 2016년 3월부터 6월까지 10년 이상 유기농을 실천한 토양의 화학적 특성과 함께 유기농가의 토양 관리를 위해 사용한 자재의 종류를 조 사하였다. 그 결과 유기농가에서는 토양 양분관리를 위해 주로 자가제조퇴․ 액비 및 시판자 재를 사용하고 있어 외부 투입자재의 사용빈도가 높음을 알 수 있었다. 그 중 57%는 가축 분뇨가 포함된 자재를 이용하여 토양관리를 하고 있었고 자재 성분분석 결과 가축분의 구 성 비율에 따라 자재의 성분함량이 다양하게 나타났다. 토양분석결과 10년 이상 유기농재 배를 한 지점의 양분함량은 대체로 높은 경향을 보였으며 농가에서 주로 사용하는 자재에 따라 토양 화학성이 차이가 나는 것을 알 수 있었다. 특히 가축분퇴비를 주로 사용하는 농 가는 교환성 칼슘과 칼륨이 과잉 존재하는 경향을 보였다. 또한 시판자재 분석결과 부숙유 기질비료는 가축분의 종류와 비율에 따라 성분함량 차이가 크게 나타났다. 이러한 외부투 입자재에 의존한 토양관리는 토양 내 양분 불균형을 야기할 수 있다. 토양 내 양분 불균형 은 작물 생산성을 악화시키고 환경오염의 우려가 있어 농가 및 연구현장에서 이를 개선하 기 위한 노력이 필요하다. 농가수준에서 토양 양분관리를 위해 사용하기 용이한 시판 부숙 유기질비료의 성분함량을 고려한 신중한 투입이 필요하며, 또한 이러한 유기농경지에서의 양분 불균형 해소를 위해 집적된 양분의 이용률을 증대시키는 방안에 대한 연구가 필요할 것으로 생각된다.

남극의 토양 환경에 대한 기초자료를 확보하기 위하여 킹조지섬 바톤반도에 위치한 세종기지 주변지역의 토양 성분과 토양을 구성하는 점토광물의 종류 및 분포, 조성을 규명하고자 X선 회절분석 과 습식분석(철의 산화도와 양이온 교환능 측정), 투과전자현미경-전자에너지 손실 분광분석, 전함량 분석을 실시하였다. X선 회절 분석을 실시한 결과, 스멕타이트, 일라이트, 카올리나이트, 녹니석이 주 요 점토광물로 함유되어 있으며 석영, 사장석 등의 화산활동 기원 초생광물도 함께 수반되어 나타났 다. 토양 시료의 철 산화도 분포는 대부분의 지점에서 Fe(II)이 20~40%, Fe(III)이 50% 이상 토양 입 자상에 존재하였고, 나노 스케일에서 스멕타이트를 분석했을 때 광물 구조 내 Fe(III)/ΣFe이 약 57% 로 분석되어 전체 토양의 철 산화도와 유사한 결과를 보였다. 양이온 교환능은 전반적으로 100-300 meq/kg 범위였으며, 시료 채취지점에 따른 유의미한 차이는 보이지 않았다. 전체 토양의 전함량 분석 결과, 광물의 주 구성 원소(Mg, K, Na, Al, Fe)는 지점에 따른 차이를 보이고 있는 반면, 중금속 원소 (Co, Ni, Cu, Zn, Mn)는 지점별로 유사하게 나타났다. 이러한 결과들은 토양을 구성하는 기반암이 기 본 원소 분포에 영향을 줄 수 있음을 보여준다. 따라서 본 연구 결과는 남극 지표 토양환경과 토양 내 점토광물에 대한 기초자료 확보에 있어서 많은 도움이 될 것으로 기대된다.

Effects of different soil water conditions on fruit characteristics were investigated in 5-year-old ‘Nero’ black chokeberry trees (Aronia melanocarpa). Three kinds of drought stresses, including low water deficit, severe water deficit, and very severe water deficit, due to decline of soil water decreased the fruit quality of weight of 10 berries, soluble solid content, and anthocyanin, compared with the control (consistent water supply) during the harvest period. After longer drought stress, supply of soil water could induce berry cracking because cell size of epidermis of fruits contracted, whereas cell size of sub-epidermis and flesh expanded. Thus periodic water supply using water supply facility is needed for yield and quality of ‘Nero’ black chokeberry fruits.

This study was carried out to provide the basic informations on the sustainable management methods for soil resources by determining the soil physico-chemical properties of specialized plant gardens (Sedum garden, Fern garden, Medicinal plant garden, Ornament plant garden, Rare & endemic plant garden, and Shrub garden) and forest in Korea National Arboretum. Soil particle size showed similar distribution except for Sedum garden and Medicinal plant garden. Soil bulk densities were significantly difference among forest and specialized plant garden (p<0.05) and ranged from 0.79 g/cm 3 in Sedum garden to 1.13 g/cm 3 in shrub garden. Sedum garden and medicinal plant garden showed significantly low of soil moisture content (p<0.05). Soil pH ranged from 4.87 in Sedum garden to 5.41 in rare & endemic plant garden. Soil organic matter content ranged from 2.61% in Sedum garden to 4.71% in forest. The lower value in total N content was 0.11% in Sedum garden and 0.18% in medicinal plant garden. Available phosphorus was significantly lower in Sedum garden and medicinal plant garden than in other specialized plant garden of ranging from 16.90 ppm to 20.34 ppm (p<0.05). The contents of inorganic NH4 + and NO3 - were significantly different among the specialized plant gardens (p<0.05). The ratios of NO3 - to total inorganic N content ranged from 28% in Sedum garden to 44% in fern garden and forest. N mineralization and nitrification rate were also significantly different among the specialized plant gardens (p<0.05).

Background: Some plants have harmful effects on fungi and bacteria as well as other plants. Incorporating such plant into soil as green manure is effective in reducing population densities of soil pathogens. Methods and Results: Twenty-three species of green manure crops were cultivated after the harvest of 6-year-old ginseng and then incorporated into the soil at the flowering stage. The following year, the root rot ratio of 2-year-old ginseng and soil chemical properties were investigated. In the absence of green manure addition, the NO3 content, electric conductivity (EC), and K content decreased by 95%, 79% and 65%, respectively. In the presence of green manure addition, P2O5 and NO3 contents reduced by 41% and 25%, respectively. The “survived root ratio” of 2-year-old ginseng significantly increased by 56.2%, 47.5%, and 47.3%, in the Sorghum sudanense, Ricinus communis and Helianthus tuberosus treatment, respectively. In addition, there was a significant increase in the “survived root ratio” in the Secale cereale, Chrysanthemum morifolium, Atractylodes macrocephala, and Smallanthus sonchifolius treatments. The “survived root ratio” of ginseng showed a significant positive correlation with the soil pH and a negative correlation with the NO3 contents, and EC. Conclusions: Cultivation of plant form the Chrysanthemum family as green manure, using mainly the rhizomes was effective for the control of root rot disease of ginseng.

About 4,800 soil drums were generated in the process of maintenance on KRR site (Korea Research Reactor) in Seoul. Most of the drums are processed by regulatory clearance in 2007-2008 and the remaining 1800 drums are currently stored in KAERI (Korea Atomic Energy Research Institute). To decide a treatment method of radioactive soil for final disposal, the soil is classified according to a particle size. Based on the results of the radioactivity concentration for the classified soil, methods such as regulatory clearance, decommissioning, and solidification were decided. Many papers show that radioactive soil is disposed of using a decontamination agent or other method. But it is difficult to decontaminate radioactive particles from fine soil particles because the adsorptive power of fine soil particles is too strong. This study was focused on finding a particle size distribution of radioactive soil that can be used as an operating range for cement solidification produced by a suitable ratio of radioactive soil for final disposal. Workability, free-standing water, compressive strength, immersion, and leaching tests were carried out to evaluate characteristics of the cement solidification. Cement solidification is the only method for final disposal because radioactive soil particle sizes below 500 μm exceed the regulatory clearance criteria (< 0.1 Bq/g). According to the test results for cement solidification, 0.4 water/cement and 0.5 soil/cement ratios are the most appropriate operating ranges.

This study was aimed at determining the changes in heavy metal removal efficiency at different acid concentrations in a micro-nanobubble soil washing system and pickling process that is used to dispose of heavy metals. For this purpose, the initial and final heavy metal concentrations were measured to calculate the heavy metal removal efficiency 5, 10, 20, 30, 60, and 120 min into the experiment. Soil contaminated by heavy metals and extracted from 0~15 cm below the surface of a vehicle junkyard in the city of U was used in the experiment. The extracted soil was air-dried for 24 h, after which a No. 10 (2 mm) was used as a filter to remove large particles and other substances from the soil as well as to even out the samples. As for the operating conditions, the air inflow rate in the micro-nano bubble soil washing system was fixed at 2 L/min,; with the concentration of hydrogen peroxide being adjusted to 5%, 10%, or 15%. The treatment lasted 120 min. The results showed that when the concentration of hydrogen peroxide was 5%, the efficiency of Zn removal was 27.4%, whereas those of Ni and Pb were 28.7% and 22.8%, respectively. When the concentration of hydrogen peroxide was 10%, the efficiency of Zn removal was 38.7%, whereas those of Ni and Pb were 42.6% and 28.6%, respectively. When the concentration of hydrogen peroxide was 15%, the efficiency of Zn removal was 49.7%, whereas those of Ni and Pb were 57.1% and 42.6%, respectively. Therefore, the efficiency of removal of all three heavy metals was the highest when the hydrogen peroxide concentration was 15%.

This experiment was conducted to assess changes to the chemical properties of soil and applicability in a case of rice cultivation with organic fertilizers. The investigator applied organic fertilizers to rice cultivation for five years to examine changes to the chemical properties of soil and found that the experiment group of organic fertilizers made an ongoing increase in pH, organism content, and available phosphate content annually compared with the control group with no big differences according to the amounts of organic fertilizers used. As for the yield components, there were no statistical differences in the number of spikelets and grain filling rate between the experiment group of organic fertilizers and the control group. The experiment group recorded a higher level in 1,000 seeds weight and yield than the control group. Experiment Group 4 recorded the highest level at 29.11 kg of 1,000 seeds weight. Experiment Groups 3 and 4, which used 222 kg and 267 kg per 10 a, respectively, recorded 576 kg and 572 kg of yield, respectively, which were 4.7% and 4.1% higher than 549 kg of control group, respectively. As for the quality of brown rice, there were no statistical differences in the head rice percentage between the control and experiment group, both of which were in the range of 83.2-85.7%. As for the protein content, Experiment Groups 3 and 4, both of which used a lot of organic fertilizers, were in the range of 6.9-7.1%, which was lower than 7.5% of control group. Those findings indicate that the long-term application of organic fertilizers can improve the chemical properties of soil and increase the yield more than the conventional method of fertilizer application. The findings also suggest that it will be effective to apply 222 kg of organic fertilizers or more per 10 a.

This study was carried out to investigate the effect of no-tillage on sequential cropping supported from recycling of first crop ridge on the productivity of crop and physical properties of soil under green house condition. This study is a part of “No-tillage agriculture of Korea-type on recycled ridge”. From results for distribution of soil particle size with time process after tillage, soil particles were composed with granular structure in both tillage and no-tillage. No-tillage soil in distribution of above 2 mm soil particle increased at top soil and subsoil compared with tillage soil. Tillage and one year of no-tillage soil were not a significant difference at above 0.25 mm~below 0.5 mm, above 0.5 mm~below 1.0 mm, and above 1.0 mm of water-stable aggregate. Two years of no-tillage soil was significantly increased by 8.2%, 4.5%, and 1.7% at above 0.25 mm~below 0.5 mm, above 0.5 mm~below 1.0 mm, and above 1.0 mm of water-stable aggregate, respectively, compared with one year of no-tillage. Bulk density of top soil was 1.10 MG m3 at tillage and 1.30 MG m3 at one year of no-tillage. Bulk density of top soil was 1.14 MG m3 at two years and 1.03 MG m3 at three years of no-tillage, respectively. Bulk density of subsoil was a similar tendency. Solid phase ratio in top soil and subsoil was increased at one year of no-tillage compared with tillage soil, while soil phase ratio decreased at two and three years of no-tillage. Pore space ratio in tillage top soil (58.5%) was decreased by 8.5% at compared with no-tillage soil (51.0%). Pore space ratio was 56.9% and 61.2% at two and three years of no-tillage soil, respectively. Subsoil was a similar tendency. Gaseous phase ratio was decreased at one year of no-tillage soil, and increased at two and three years of no-tillage soil compared with tillage soil. Liquid phase ratio in top soil was increased at one year of no-tillage (28.3%), and decreased at two years (23.4%) and at three years (18.3 %) of no-tillage soil compared with tillage soil (24.2%). Subsoil was a similar tendency. Liquid phase ratio in subsoil was increased than top soil.

This study was carried out to investigate the effect of no-tillage on sequential cropping supported from recycling of first crop ridge on the growth of pepper plant and physical properties of soil under green house condition.1. Degree of crack on soil by tillage and no-tillageSoil cracks found in ridge and not found in row. At five months of tillage, crack number and crack length in length ridge were 3 and 37~51 cm in tillage. Maximum width and maximum depth in length ridge were 30 mm and 15.3cm in tillage. Crack number and crack length in width ridge were 7.5 and 7~28 cm in tillage. Maximum width and maximum depth in width ridge were 29 mm and 15.3 cm in tillage. At a year of no-tillage, crack number and crack length in length ridge were 1.0 and 140~200 cm in tillage. Maximum width and maximum depth in length ridge were 18 mm and 30 cm in a year of no-tillage. Crack number and crack length in width ridge were 11 and 6~22 cm in a year of no-tillage. Maximum width and maximum depth in width ridge were 22 mm and 18.5 cm in a year of no-tillage. Soil crack was not found at 2 years of no-tillage in sandy Jungdong series (jd) soil. Soil crack was found at 7 years of no-tillage in clayish Jisan series (ji) soil.2. Penetration resistance on soilPenetration resistance was increased significantly at no-tillage in Jungdong series (jd). Depth of cultivation layer was extended at no-tillage soil compared with tillage soil. Penetration resistance of plow pan was decreased at 1 year of no-tillage compared with than tillage soil. Penetration resistance was linearly increased with increasing soil depth at tillage in Jisan series (ji). Penetration resistance on top soil was remarkably increased and then maintained continuously at no-tillage soil.3. Drainage and moisture content of soilMoisture content of ridge in top soil was not significant difference at both tillage and no-tillage. Moisture content of ridge in 20 cm soil was 14% at no-tillage soil and 25% at tillage soil.4. Change of capacity to retain water in soilCapacity to retain water in top soil was not significant difference at 1 bar both tillage and no-tillage. Capacity to retain water in soil was slightly higher tendency in 1 year and 2 years of no-tillage soil than tillage soil. Capacity to retain water in soil was increased at 15 bar both tillage and no-tillage. Capacity to retain water in subsoil was slightly higher tendency at 1 bar and 3 bar in 2 years of no-tillage than tillage soil and a year of no-tillage soil.

Green manure has been used as alternative to chemical fertilizer. To evaluate the effect of green manure on the chemical properties of top-soil and sorghum yield, hairy vetch (Vicia villosa Roth, HV), manure barley (MB), and a mixture of hairy vetch and manure barley (HV+MB) were incorporated into the soil at a rate of 100 kg-N N ha -1 before the sorghum was transplanted. Total biomass of sorghum grown in the HV, MB, and HV+MB treatments was 13.1, 31.6, and 25.2 t ha -1 , respectively, and the nitrogen production of the treatments was 81, 74, and 145 ㎏ ha -1 , respectively. The SPAD value of the uppermost leaf of sorghum plants grown in the soils with HV, MB, or HV+MB were very similar until heading stage; however, at maturity, the SPAD value of sorghum cultivated in the soils with HV was lower than that of sorghum in the soils with MB or HV+MB. This could be because the nitrogen release from HV was too rapid to supply nitrogen to sorghum during the later stage of grain filling. Compared with chemical fertilizers, the incorporation of green manure increased the pH, exchangeable cations (K + , Mg ++ , and Ca ++ ), and total nitrogen in soil postharvest, indicating an improvement in soil chemical properties. Total carbon content increased in soil with green manure incorporated, but decreased in the chemical fertilized soil, suggesting that sorghum cultivation using green manure may sequester carbon in soils. The yield of sorghum cultivated with green manure was not different from the yield of sorghum cultivated with chemical fertilizers. These results suggest that the mixture of hairy vetch and manure barley can be a useful chemical fertilizer alternative in sorghum cultivation.

To understand the characteristics of vanadium leaching from soils formed by the weathering of basalts, paleo soil at Gosan, Jeju Island, Korea, and several present-day soils from neighboring areas were collected. Leaching experiments were carried out by two approaches: 1) batch experiments under various geochemical conditions (redox potential (Eh) and pH) and 2) continuous leaching experiments under conditions similar to those of natural environments. From the batch experiments, leached vanadium concentrations were highest under alkaline (NaOH) conditions, with a maximum value of 2,870 μg/L, and were meaningful (maximum value, 114 μg/L) under oxidizing (H2O2) conditions, whereas concentrations under other conditions (acidic-HCl, neutral-NaHCO3, and reducing-Na2S2O3) were negligible. This indicated that the geochemical conditions, in which soil-water reactions occurred to form groundwater with high vanadium concentrations, were under alkaline-oxidizing conditions. From the continuous leaching experiments, the pH and leached vanadium concentrations of the solution were in the ranges of 5.45 5.58 and 6 9 μg/L, respectively, under CO2 supersaturation conditions for the first 15 days, whereas values under O2 aeration conditions after the next 15 days increased to 8.48 8.62 and 9.7 12.2 μg/L, respectively. Vanadium concentrations from the latter continuous leaching experiments were similar to the average concentration of groundwater in Jeju Island (11.2 μg/L). Furthermore leached vanadium concentrations in continuous leaching experiments were highly correlated with pH and Al, Cr, Fe, Mn and Zn concentrations. The results of this study showed that 1) alkaline-oxidizing conditions of water-rock (soil) interactions were essential to form vanadium-rich groundwater and 2) volcanic soils can be a potential source of vanadium in Jeju Island groundwater.

Elemental mercury has a very high volatility allowing easy dissipation from water or soil into air. To better understand how the kinetics of diffusion of elemental mercury through a medium, which is soil in this study, a mercury diffusion column experiment was done. The correlation between temperature and equilibrium concentrations of mercury in standardized soil samples and a pure mercury standard were determined. Total mercury concentrations were analysed using CVAFS. The effect of time and soil depth to the kinetics of mercury diffusion were determined. Differences in mercury concentrations at different sampling probes were observed during the first few gas phase analyses. Equilibrium was reached through the column after 72 hours.