• The Journal of Natural Sciences
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• v.11 no.1
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• pp.131-135
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• 1999

The objective of this research was to improve moisture retention capacity of pine bark. To achieve this, barks were ground with Wiley mill of hammer mill and were blended with recycled rockwool. Then, changes of soil physical properties were determined. The percentage of particles larger than 5.6 mm was 86.5% in raw materials. The percentage of particles larger than 1 mm decreased and those of particles smaller than 1 mm increased by grinding with Wiley mill or hammer mill. Grinding with Wiley mill showed better effect than those of hammer mill in decreasing particle size distribution. Grinding resulted in decreased total porosity (TP) and air space (AS) and increased container capacity (CC) and residual water content (RW), indication improved moisture retention capacity. The material ground with Wiley mill, than blended with 50% recycled rockwool had 81.1%, 67.7%, 13.5% and 235 ml in TP, CC, AS and RW, respectively. These results indicated that moisture retention capacity was improved by blending with recycled rockwood, but aeration of root media was much better than those of peat+vermiculite(1:1, v/v), which is commonly used in commercial production.

• Proceedings of the Plant Resources Society of Korea Conference
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• 2020.08a
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• pp.54-54
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• 2020

배추는 근본적으로 저온성 작물로 고온에 견디는 힘이 약할 뿐 아니라 가뭄이나 다습에도 취약하다. 그런데 2007년 이 후 매년 봄·초여름 가뭄이 지속되고 있으며, 예전처럼 강우에 의한 피해보다는 빈번히 나타나는 고온, 가뭄, 폭염 등 이상기상 환경조건에서 병 발생 및 생장지연으로 고랭지배추의 안정 생산이 위협받고 있다. 가뭄이 매년 지속됨에 따라 고랭지배추 재배지에서도 관수의 필요성이 인식되면서 관수를 실시하고 있으며, 대부분 스프링클러로 관수하고, 분수호스나 점적호스도 일부 이용하고 있으나 아직 토양수분, 토성이나 작물상태, 재배시기 등 환경요인을 고려한 과학적인 수분관리가 이루어지지 못하고 있어 고품질 안정생산을 위해서는 수분관리의 과학화가 필요한 실정이다. 관비재배는 적정한 비료를 필요한 위치에 공급하는 방식으로 비료의 효율을 높이면서 환경오염을 최소화하고, 비료과다 시용에 따른 환경오염 등을 회피할 수 있는 좋은 수단이다. 본 연구는 앞으로 고랭지배추 점적관수재배시 가뭄 극복과 효율적인 시비를 위한 적정 관비농도를 구명하고자 하였다. 배추품종은 수호를 이용하였으며 관비 EC농도(dS/m)는 0.4, 0.6, 0.8, 1.0, 1.2, 1.4 등 6처리를 두었으며 기준시비량은 N-P-K=32.0-7.8-19.8kg/10a로 하였다. 시험은 고령지농업연구소내 유리온실에서 4월 상순부터 5월 하순까지 직경 20cm 사각화분에 정식하여 재배하였다. 관비는 정식후 15일부터 7일 간격으로 5회 주었으며 관비량은 1회 화분당 65ml를 주었다. 화분은 완전임의배치 3반복으로 배치하였다. 초장은 정식후 38일까지 컸으며 엽장은 정식후 52일까지도 크는 경향을 보였다. 엽폭은 정식후 45일에 가장 많이 컸다. 초장, 엽장, 엽폭 모두 관비농도가 높을수록 커지는 경향이었으며 EC농도(dS/m) 1.4에서 가장 높게 나타났다. 주당 엽수와 주중도 EC농도가 높아질수록 많아졌으며 EC농도 1.4 처리에서 가장 많았고 그 다음이 EC 1.2 처리였다. 그러므로 관비 농도는 EC 1.4 dS/m 로 주는 것이 배추 생육에 좋을 것으로 생각된다.

• Korean Journal of Soil Science and Fertilizer
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• v.20 no.3
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• pp.209-216
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• 1987

The experiments were carried out in lab. as well as in pots, to develop the agricultural usage of water swellable polymer, a kind of polyacrylic acid(K-sorb) synthesized by the Korea Advanced Institute of Science & Technology (KAIST) recently. The changes of soil physical properties and the influences to crops were investigated with various levels of K-sorb. When the K-sorb mixed with soils and soaked up distilled water, the volume of soils increased with the increase of soil available water contents and increase of K-sorb application levels. The rate increase of soil available water was higher in the coarse textured soils than in the fine while the swelling rate of soil volume showed adverse tendencies. A positive linear regression was observed between the contents of available soil water and levels of K-sorb. K-sorb application decreased bulk density and hardness due to the increase of porosity after soybean cultivation. The permeability in coarser textured soils such as sandy and coarse loamy families was decreased with the increase of K-sorb but in the medium textured soils it was opposite. At higher levels of K-sorb, about 0.5%, the permeability abruptly decreased due to dispersion and vertical movement in silty soils, while it was not changed in fine clayey soils but has the same trend with silty soils. In the plot of 0.3% of K-sorb application, the growth of soybean such as number of pods and stem length etc. increased and the yield also increased about 1.2-1.8 times of control. The optimum amounts of K-sorb were slightly different according to soil texture but estimated from regression curves were about 0.2% to 0.35% of soils in dry weight bases.

• Korean Journal of Soil Science and Fertilizer
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• v.43 no.3
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• pp.363-373
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• 2010

"Curve number" (CN) indicates the runoff potential of an area. The US Soil Conservation Service (SCS)'s CN method is a simple, widely used, and efficient method for estimating the runoff from a rainfall event in a particular area, especially in ungauged basins. The use of soil maps requested from end-users was dominant up to about 80% of total use for estimating CN based rainfall-runoff. This study introduce the use of soil maps with respect to hydrologic and watershed management focused on hydrologic soil group and a case study resulted in assessing effective rainfall and runoff hydrograph based on SCS-CN method in a small watershed. The ratio of distribution areas for hydrologic soil group based on detailed soil map (1:25,000) of Korea were 42.2% (A), 29.4% (B), 18.5% (C), and 9.9% (D) for HSG 1995, and 35.1% (A), 15.7% (B), 5.5% (C), and 43.7% (D) for HSG 2006, respectively. The ratio of D group in HSG 2006 accounted for 43.7% of the total and 34.1% reclassified from A, B, and C groups of HSG 1995. Similarity between HSG 1995 and 2006 was about 55%. Our study area was located in Sosu-myeon, Goesan-gun including an approx. 44 $km^2$-catchment, Chungchungbuk-do. We used a digital elevation model (DEM) to delineate the catchments. The soils were classified into 4 hydrologic soil groups on the basis of measured infiltration rate and a model of the representative soils of the study area reported by Jung et al. 2006. Digital soil maps (1:5,000) were used for classifying hydrologic soil groups on the basis of soil series unit. Using high resolution satellite images, we delineated the boundary of each field or other parcel on computer screen, then surveyed the land use and cover in each. We calculated CN for each and used those data and a land use and cover map and a hydrologic soil map to estimate runoff. CN values, which are ranged from 0 (no runoff) to 100 (all precipitation runs off), of the catchment were 73 by HSG 1995 and 79 by HSG 2006, respectively. Each runoff response, peak runoff and time-to-peak, was examined using the SCS triangular synthetic unit hydrograph, and the results of HSG 2006 showed better agreement with the field observed data than those with use of HSG 1995.

• Proceedings of the Korea Water Resources Association Conference
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• 2020.06a
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• pp.386-386
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• 2020

가뭄은 강수, 증발산, 대기온도, 토양수분 등 다양한 수문기상학적 인자들이 복합적으로 작용하여 발생되기 때문에 가뭄의 정확한 사상을 분석하는 것은 매우 어렵다. 또한 어떤 요인을 중심으로 고려하느냐에 따라 가뭄은 다양한 시각으로 정의되고 있다. 일정기간 평균 강수량보다 적은 강수로 인해 건조한 날이 지속되는 것, 즉 기상요소를 중심으로 가뭄을 정의하는 것을 기상학적 가뭄이라 하며, 작물의 생육에 필요한 수분을 중심으로 고려하는 것을 농업적 가뭄이라 한다. 또한 하천유량, 댐 저수량 등 전반적인 수자원 공급원의 부족을 수문학적 가뭄이라 한다. 이와 같이 다양하게 나타는 가뭄의 발생특성을 정량적으로 해석하기 위해 다양한 가뭄지수가 개발되어 왔다. 그러나 현재까지 개발된 가뭄지수들은 공통적으로 정형데이터를 활용하여 산정한다. 하지만 최근에는 비정형데이터를 활용하여 지수(Index)를 산정하거나, 재난관리에 적용하는 등 비정형 데이터의 활용이 급증하고 있다. 따라서 본 연구에서는 비정형 데이터(뉴스 데이터)를 활용하여 가뭄지수를 산정하고 기존의 가뭄지수들과의 상관성 분석을 실시 한 뒤, 지수결합을 통해 가뭄사상 분석의 새로운 방안을 제시하고자 하였다. 본 연구의 공간적범위는 2014~2015 충남서북부가뭄 지역 중 가장 큰 피해를 입었던 보령지역으로 선정하였으며 시간적범위는 2013~2016년으로 설정하였다. 비정형 데이터의 구축은 크롤링(Crawling)을 활용하여 네이버 뉴스의 기사를 수집하였으며 자료의 신뢰성을 위해 URL이 동일한 중복기사 및 '보령', '가뭄' 단어가 없는 기사는 제거하였다. 구축된 데이터를 기반으로 월별 빈도를 산출하고 표준점수(Z-score)로 환산하여 가뭄지수를 산정하였다. 산정된 가뭄지수가 어떤 가뭄의 유형(기상학적, 농업적, 수문학적)을 보이는지 확인하기 위해 기존의 가뭄지수들과 상관성분석을 실시하였으며, 가장 높은 상관성을 보이는 가뭄지수와 결합을 통해 새로운 가뭄 사상을 분석하였다. 본 연구에서 진행한 가뭄사상 분석은 향후 가뭄만이 아니라 다양한 재난분야에서 비정형 데이터를 활용한 분석의 기초로자료로 활용될 수 있을 것이다.

• Korean Journal of Soil Science and Fertilizer
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• v.29 no.2
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• pp.145-149
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• 1996

Depending on compost treatment the changes of radish morphology and soil physico-chemical properties were investigated in the sandy loam soil, pH of the soil was decreased and the contents of organic matter, total nitrogen, phosphate and cation exchange capacity was increased with increase of compost. Root weight and length were the lowest, but deficit rate was the highest(79.3%) in the treatment of 120Mg/ha of compost. The contents of chlorophyll and sugars were increased with increasing the amount of compost treatment, but the inorganics were scarcely changed. The nitrate content in radish root ranged from 10 to 120mg/kg in various treatments.

• Korean Journal of Soil Science and Fertilizer
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• v.24 no.3
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• pp.165-170
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• 1991

Effects of liming and starch application on the soil pH and mineralization of organic nitrogen were compared to control at $30+/10^{\circ}C$ incubation for six weeks in two soil types(loam, sandy loam) adjusted with 80% of field moisture capacity. 1. While soil pH was increased abruptyl one week after incubation in loam applied with lime and lime+starch, it tended to decrease at control during incubation period. Liming on sandy loam increased soil pH, and application of lime+starch together showed high pH at first week of incubation which was lowered slowly after wards. Significant changes in soil pH was not detected at control or starch application only. 2. The content of $NH_3-N$ in loam started to increse three weeks after incubation, and was maximized at fifth week. Positive correlation was shown at control during incubation period between soil pH and $NO_3-N$ content. Level of $NO_3-N$ content applied with starch or lime+starch was low compared to control. 3. The $NH_4-N$ content was high when sandy loam was applied with lime+starch together. At the first week of incubation, the $NO_3-N$ content was high at control or lime application.

• Proceedings of the Korean Society of Organic Agriculture Conference
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• 2009.12a
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• pp.282-282
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• 2009

환경오염에 대한 우려 및 안전농산물에 대한 소비자욕구 증대로 유기농산물 시장규모가 최근 3년간 2.8배 성장 추세이다. 친환경농산물 인증면적은 '00년 2,039 ha에서 '07년 122,882 ha로 급격히 증가하고 있으나 생태적 원리에 부합된 벼 재배기술이 부족하며 특히 무경운 논토양에 대한 경영분석 자료는 거의 없는 실정이다. 본 연구는 유기농업기술을 종합적으로 투입한 시범마을을 육성하기 위하여 하동군 양보면 예성마을 1ha를 대상으로 관행농업과 무경운 자운영 피복 벼 기계이앙을 실증하여 경제적인 효과를 검토하였다. 토양 관리를 위해 2007년 9월 10일에 자운영을 3 kg/10a 파종하여 겨울철 토양 생태계를 유지하였고 화학비료나 농약을 사용하지 않았다. 볍씨 소독은 마른 종자를 60 $^{\circ}C$에서 8분간 침지하는 열탕침법을 이용하였으며 논 물담기는 5월 28일경 15 cm 이상 깊게 하여 자운영이 잘 분해되도록 하였다. 기계이앙은 6월 10일경 표면 1 cm 이내의 물 깊이에서 식부장치를 최대한 깊게하고 주수는 주당 5-7주 정도로 실시하였으며 기계이앙 후에는 5일 정도 물을 담지 않고 그대로 두고 그 후 물을 10 cm 이상 깊게 하여 잡초발생을 억제하였다. 중간낙수는 7월 10일경 1회 처리하였고 수확기 낙수는 9월 23일 실시하였다. 무경운 처리구의 이앙전 토양 가밀도는 관행 1.30 g $cm^{-3}$ 비해 0.09 g $cm^{-3}$ 정도 가벼운 것으로 나타났고 공극률은 관행 50.8%에 비해 3.5% 높은 것으로 나타났으며 특히 수분률이 3.5% 높았다. 무경운 자운영 피복 기계이앙 처리구의 잡초발생 건물량은 7월 4일경 피 8.8 g $m^{-2}$, 여뀌 10.8 g $m^{-2}$ 이었으며 9월 18일에는 피 16.0 g $m^{-2}$, 여뀌 12.3 g $m^{-2}$였다. 수확기 관행처리구의 주당 이삭수는 16.7개, 수당립수는 101개, 천립중은 25.4 g, 등숙비율은 82.3%로 수량은 517 kg $10a^{-1}$ 였으며 무경운 자운영 피복 기계이앙은 주당 이삭수가 14.1개, 수당 립수는 103개, 천립중은 26.2 g, 등숙비율은 91.2%로 수량이 456 kg $10a^{-1}$였다. 무경운 자운영피복 벼 기계이앙은 기경작업이나 시비작업 등이 없으므로 노동력이 60% 절감되었으며 농가소득은 5% 증대되었다. 따라서 농업분야 저탄소 녹색성장과 관련하여 자연 생태계를 보전하면서 농가소득을 유지할 수 있는 방법으로 무경운 자운영 피복 벼 기계이앙이 효과적인 것으로 판단되었다.

• KOREAN JOURNAL OF CROP SCIENCE
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• v.51 no.7
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• pp.593-598
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• 2006

This study was conducted to investigate the effect of tillage methods such as plowing and rotary tillage (PRT), rotary tillage (RTG), no-tillage after barley straw application (NTB), and barley straw mulching after plowing and rotary tillage (BPR) on the growth and the yield of soybean when cultivated after the cultivation of barley. The methods were compared with the control method in which plowing and rotary tillage after barley straw incineration was applied. Barley straw application resulted in increase in organic matter, total nitrogen, phosphate, and exchangeable cation regardless of tillage methods. Porosity and moisture level in paddy soil was ranked as follows : PRT > RTG > BPR > control > NTB. Decomposition rate of barley straw dramatically increased to 41.7% toward 30 days after soybean sowing, higher in NTB, DRB, and RTG than in BPR. Weed occurrence was decreased 36% in NTB and 40% in BPR. Root activity, nodulation and the dry weight per plant of soybean at flowering stage were highest in NTB and lowest in PRT. Soybean yield in NTB was 3,070 kg/ha increasing 19%, whereas that in PRT was not increased. Therefore in case of a frequent rain during the cultivation of soybean in paddy field PRT could result in excess moisture level in soil, the cultivation without tillage is desirable.

• Journal of Korean Society of Environmental Engineers
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• v.32 no.2
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• pp.185-192
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• 2010

The objective of this study was to investigate the effectiveness of stabilization for army firing range soil highly contaminated with Pb (total Pb: 29,000 mg/kg) using calcined waste oyster shells. The calcination was conducted to activate quicklime from calcite. In order to evaluate the effectiveness of calcination, both natural oyster shells (NOS) and calcined oyster shells (COS) were applied to the Pb contaminated soil. Stabilization was conducted by mixing the contaminated soil with oyster shell media at 5-20 wt% and cured for 28 days. Following 28 days of curing, Pb leachability was measured based on the Korean Standard Test method (0.1 N HCl extraction). The treatment results showed that the COS treatment outperformed the NOS treatment. All of the NOS treatments failed to meet the Korean warning standard of 100 mg/kg. However, the Pb concentrations were significantly reduced to 47 mg/kg and 3 mg/kg upon 15 wt% and 20 wt% COS treatments, respectively which passed the Korean warning standard. Moreover, -#20 mesh materials were more effective than the -#10 mesh materials in effectively reducing Pb leachability. The scanning electron microscopy (SEM)-energy dispersive X-ray spectroscopy (EDX) results indicated that Pb immobilization was strongly linked to Al and Si.