• 농업과학연구
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• 제49권2호
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• pp.379-387
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• 2022

A large amount of the mineral nitrogen is necessary for crop growth. With the use of nitrogen fertilizers, agricultural yield has increased during the last few decades. However, at the same time, nitrate from the cultivated land can be a source of environmental pollution, especially in water systems. For nitrogen management, it is necessary to analyze the pattern of nitrogen movement in soil. In this study, nitrogen leaching in upland soils was evaluated using undisturbed lysimeters with different soil textures during sesame cultivation. The soil texture of the lysimeters was clay loam (Songjung series) and sandy loam (Sangju series) soils. Sesame was cultivated from May 25 to August 24 in 2020. The standard amount of NPK fertilizer (N-P₂O₅-K₂O = 2.9-3.1-3.2 kg·10 a^-1) was applied before sowing. The amount of nitrogen leaching was calculated by multiplying the nitrogen (NO₃-N + NH₄-N) concentration and the amount of water drained below 1.5 m soil depth. The water was drained through percolation into macropores in the clay loam lysimeter. In contrast, in the sandy loam lysimeter, water drained more slowly than in the clay loam lysimeter. There was a slight difference in the total amount of leachate during the cultivation period, but the amount of nitrogen leaching was high in sandy loam soil. During the sesame cultivation period, the amount of nitrogen leaching from clay soil was 5.64 kg·10 a^-1, and 10.70 kg·10 a^-1 for sandy soil. We found that there was a difference in leaching depending on the soil physical characteristics. Therefore, it is necessary to consider the characteristics of soil to evaluate the leaching of nitrogen.

• Animal cells and systems
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• 제7권4호
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• pp.289-294
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• 2003

To quantify nutrient loading from emergent macrophytes through leaching in the littoral zones of Paldang Reservoir, we conducted incubation experiments using leaf litter of the emergent macrophyte, Zizaniz latifolia. To separate the leaching process from microbial decay, we used $HgCl_2$ to suppress microbial activity during the experiment. We measured electric conductivity, absorbance at 280nm, total nitrogen and dissolved inorganic nitrogen, total phosphorus and soluble reactive phosphorus, Na, K, Mg and Ca amounts in leaf litter and in water. In addition, we examined the effects of water temperature and ion concentrations of ambient water on the leaching process. A total of 6% of the initial ash-free dry mass of leaf litter was lost due to leaching during incubation (four days). Electric conductivity and A280 continued to increase and saturate during the incubation. To compare reaching rates of different nutrients, we fitted leaching dynamics with a hyperbolic saturation function [Y=AㆍX/(B+X)]. From these fittings, we found that ratios of leaching amounts to nutrient concentration in the litter were in the order of K > Na > Mg > P > Ca > N. Leaching from leaf litter of Z. latifolia was dependent on water temperature while it was not related with ion concentrations in the ambient water. Our results suggest that the leaching process of nutrients, especially phosphorus, from aquatic macrophytes provides considerable contribution to the eutrophication of the Paldang Reservoir ecosystem.

• 한국환경농학회지
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• 제37권3호
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• pp.166-171
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• 2018

중량식 라이시미터를 활용하여 배추 재배 중 식양토와 사양토의 질소 용탈과 질소 수지를 평가하였다. 생육 초기인 9월 초 강우로 인해 식양토와 사양토 모두 토심 150 cm 이하로 배수가 있었다. 식양토는 점토의 수축 및 작물 뿌리 등에 의해 형성된 대공극을 통해 일시적으로 배수량이 증가하였으나, 사양토는 식양토와 달리 강우량에 따라 일정하게 배수량이 증가하고, 감소하였다. 토성별로 질소 용탈량을 분석한 결과, 식양토에서는 비료의 용탈이 거의 없는 반면, 사양토에서는 식양토에 비해 5배 많은 질소 용탈이 있었다. 질소수지에서 작물 흡수량에 비해 질소 용탈량이 차지하는 비율은 적었으나 식양토에 비해 사양토에서의 용탈량이 많아 질소 수지 산정에 토성에 따른 용탈특성을 고려할 필요가 있다.

• 한국초지조사료학회지
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• 제10권2호
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• pp.84-88
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• 1990

This experiment was conducted to evaluate the effect of cutting frequency and nitrogen fertilization on $(NO_3$-N leaching losses under 12 years mixture permanent meadow, The results of this study were summarized as follows: 1. There was no difference in the $(NO_3$-N content of soil water within 1 m soil depth during the whole experimental period. It means that the content of $(NO_3$-N leaching losses was not influenced by botanical composition, cutting frequency and nitrogen fertilization in this experiment. 2. The level of $(NO_3$-N content during the whole experimental period was not in excess of 0.5 ppm level.

• 한국토양비료학회지
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• 제50권6호
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• pp.574-587
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• 2017

Excessive application of nitrogen (N) fertilizer to support switchgrass growth for bioenergy production may cause adverse environmental effects. The objective of this study was to determine optimum N application rate to increase biomass yield of switchgrass and to reduce adverse environmental effects related to N. Switchgrass was planted in May 2008 and biomass yield, N uses of switchgrass, nitrate ($NO_3$) leaching, and nitrous oxide ($N_2O$) emission were evaluated from 2010 through 2011. Total N removal significantly increased with N rate despite the fact that yield did not increased with above $56kg\;N\;ha^{-1}$ of N rate. Apparent nitrogen recoveries were 4.81 and 5.48% at 56 and $112kg\;N\;ha^{-1}$ of N rate, respectively. Nitrogen use efficiency decreased into half with increasing N rate from 56 to $112kg\;N\;ha^{-1}$. Nitrate leaching and $N_2O$ emission were related to N use of switchgrass. There was no significant difference of cumulative $NO_3$ leaching between 0 and $56kg\;N\;ha^{-1}$ but, it significantly increased at $112kg\;N\;ha^{-1}$. There was no significant difference of cumulative $N_2O$ emission among N rates in crest, but it significantly increased at $112kg\;N\;ha^{-1}$ in toe. Excessive N application rate (above $56kg\;N\;ha^{-1}$) beyond plant requirement could accelerate $NO_3$ leaching and $N_2O$ emission in switchgrass field. Overall, $56kg\;N\;ha^{-1}$ might be optimum N application rate in reducing economic waste on N fertilizer and adverse environmental impacts.

• 지질공학
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• 제23권2호
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• pp.95-104
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• 2013

농업용 저수지의 수질 개선을 위한 효율적 관리 방안은 본 연구에서 제시되었다. 홍동 저수지는 저수지 유역 내에 농경지, 산림지역, 주거지역, 그리고 축산지역 등을 포함하고 있다. 수질 환경을 복원시키기 위해 우선 저수지 내 퇴적물의 오염도를 조사되었고 저수지내 퇴적토의 잠재적인 영양염류인 분석한 결과 총질소(T-N)은 $1.06g/m^2-d{\sim}3.67g/m^2-d$로 분포를 보이고 총인(T-P)는 $0.52 g/m^2-d{\sim}1.12g/m^2-d$로 측정되었다. 또한 퇴적토 준설 시 용출 특성 분석을 위해 72시간동안 20 혐기성 조건으로 시험을 진행되었다. 총인(T-P)와 (인산염인) $PO_4$-P의 농도는 시간에 따라 비교적 일정하게 용출되는 특성이 나타났으며 총질소(T-P)의 경우에 아질산성 질소($NO_2$-N)와 질산성 질소($NO_3$-N)의 탈질산화로 인하여 그농도가 불규칙적으로 용출되는 특성을 보였다. 특히, 암모니아인 경우는 컬럼 내부의 혐기성 조건으로 형성된 낮은 pH로 인하여 질소($N_2$)와 함께 용출 양은 극히 미량으로 측정되었다.

• 한국식생활문화학회지
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• 제4권4호
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• pp.411-416
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• 1989

적채시기별 녹차의 침출조건에 따른 유리당, 총질소 및 탄닌함량은 침출온도$(55{\sim}95^{\circ}C)$가 높을수록 침출시간(30초${\sim}$10분)이 길수록 증가하였다. 침출조건에 따른 녹차의 관능검사 결과 유리당 및 총 질소는 유의성 있는 상관관계가 나타나지 않았으나 탄닌함량과는 $15{\sim}30mg/g$의 농도에서 변곡점을 형성하는 유의성 있는 상관관계(r=-0.9061)을 나타내었다. 탄닌함량과 관능검사에 의한 녹차의 최적 침출조건은 상급차의 경우 낮은 온도$(55{\sim}75^{\circ}C)$에서 단시간 ($0.5{\sim}1$분)이었고 중급차는 $85^{\circ}C$ 이하에서 2분 이내가 최적 조건이었다.

• 한국환경농학회지
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• 제12권3호
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• pp.281-297
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• 1993

Nitrogen is an element required to meet optimal plant growth. However, when it was applied (as chemical fertilizer or animal waste) more than the demand of plant and managed it unreasonably can be accumulated in subsoil and leached from soil system. Nitrogen also can be act as an pollutant to soil and water through water contamination if its concentration exceed the critical level. The concentration and downward movement of nitrate in soil is influenced by cultural practices and soil properties. High level of nitrate nitrogen in drinking water is harzadrous for animal and human health, especially for infants and the restoration of the quality of groundwater is impossible by now. Therefore it is the only way to prevent from leaching of nitrate nitrogen to keep the quality of groundwater as vital water resource. The aims of the presentation of this review paper are to understand the relationship between agricultural practices and the concentration of nitrate nitrogen in groundwater and to suggest further informations for the rational management methods to reduce the leaching of nitrate nitrogen in soil.

• 대한화학회지
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• 제11권1호
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• pp.33-37
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• 1967

The influence of impurities contained in Marmatite ores on leaching of zinc was investigated. The zinc sulfide having the same crystal structure of natural Sphalerite was prepared by heating the zinc sulfide chemically precipitated, at $650^{\circ}C$ in nitrogen atmosphere. The activation energy of the sample was 25.8 kcal per mole in the leach test when oxygen partial pressure was 5 atm. and the value was exceedingly high compared to that obtained in Marmatite ores. Synthetic zinc sulfides added with small amount of each impurities were treated in same procedure. As a result, it was found that the leaching velocity was accelerated sharply when about 1 percent of $Cu^{++}$ was blended to the sample. Larger amount of iron has also same effect but the effect was minor compared to the copper. The other impurities indicated no appreciable catalytic action.

• 분석과학
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• 제35권2호
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• pp.41-52
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• 2022

The leaching of nitrate from soil increases the concentration of elements, such as nitrogen, phosphorus, and potassium, in water, causing eutrophication. In this study, the feasibility of using clinoptilolite as an ion-exchange material to reduce nitrate leaching in soil was investigated. Soil samples were collected from three soil depths (0 - 30, 30 - 90, and 90 - 120 cm), and their sorption capacity was determined using batch experiments. The effects of contact time, initial concentration, adsorbent dosage, pH, and temperature on the removal of NO₃^- were investigated. The results showed that an initial concentration of 25 mg L^-1, a contact time of 120 min, an adsorbent dosage of 5.0 g/100 mL, a pH of 3, and a temperature of 30 ℃ are favorable conditions. The kinetic results corresponded well with a pseudo-second-order rate equation. Intra-particle diffusion also played a significant role in the initial stage of the adsorption process. Thermodynamic studies revealed that the adsorption process is spontaneous, random, and endothermic. The results suggest that a modification of clinoptilolite effectively reduces the leaching of nitrate in soil.