• 한국환경과학회지
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• 제13권3호
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• pp.245-250
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• 2004

The SBR(Sequencing Batch Reactor) process is ideally suited to treat high loading wastewater due to its high dilution rate. SBR operates by a cycle of periods consisting of filling, reacting, settling, decanting and idling. The react phases such as aeration or non-aeration, organic oxidation, nitrification, denitrification and other bio-logical reactions can be achieved in a reactor. Although the whole reactions can be achieved in a SBR with time distributing, it is hard to manage the SBR as a normal condition without recognizing a present state. The present state can be observed with nutrient sensors such as ${NH_{4}}^{+}-N$, ${NO_{2}}^{-}-N$, ${NO_{3}}^{-}-N} and ${PO_{4}}^{ 3-}-P.$ However, there is still a disadvantage to use the nutrient sensors because of their high expense and inconvenience to manage. Therefore, it is very useful to use common on-line sensors such as DO, ORP and pH, which are less expensive and more convient. Moreover, the present states and unexpected changes of SBR might be predicted by using of them. This study was conducted to get basic materials for making an inference of SBR process from ORP(oxidation reduction potential) of synthetic wastewater. The profiles of ORP, DO, and pH were under normal nitrification and denitrification were obtained to compare abnormal condition. And also, nitrite and nitrate accumulation were investigated during reaction of SBR. The bending point on ORP profile was not entirely in the low COD/NOx ratio condition. In this case, NOx was not entirely removed, and minimum ORP value was presented over -300mV. Under suitable COD/NOx ratio which complete denitrification was achieved, ORP bending point was observed and minimum ORP value was under -300m V. Under high COD/NOx ratio, ORP bending point was not detected at the first subcycle because of the fast denitrification and minimum ORP value was under -300mV at the time.

• 환경생물
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• 제21권4호
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• pp.400-404
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• 2003

This study was to evaluate the effects of gamma irradiation on the germination, nutrient concentrations and growth of spinach and radish. Both the spinach and radish seeds exhibited relatively higher germination rates in response to the low doses of gamma irradiation compared to the non -irradiated control. Leaf DW of the radish did not respond to gamma irradiation but that of the spinach increased significantly in response to a gamma radiation of 4 Gy (P< 0.05). Leaf growth parameters of the spinach including the leaf area and SLA (leaf area/leaf dry weight) also demonstrated increased responses to gamma irradiation. R/S (root dry weight/shoot dry weight), root DW and root length of the spinach exhibited a positive response to gamma irradiation while those of the radish did not. In contrast, SRL (root length/root dry weight) significantly decreased with gamma irradiation at 8 Gy for the spinach, but not for the radish. The tissue nitrogen concentrations of the spinach showed an increased response to gamma irradiation while that of the radish did not. Furthermore, higher concentrations of phosphorus, potassium, calcium and magnesium were found in the irradiated spinach, but not in the irradiated radish. It seems that the non-specific physiological and/or biochemical activities of spinach might be accelerated by gamma irradiation, possibly accounting for the stimulation of nutrient uptake from the root media and early biomass accumulation in the current study.

• 한국토양비료학회지
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• 제49권6호
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• pp.819-825
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• 2016

Monitoring of soil fertility and crop productivity in long-term application of silicate fertilizers is necessary to use fertilizers efficiently. This study was conducted to investigate effects of continuous application of silicate fertilizer for rice cultivation from 1969 to 2014. The treatments were no silicate fertilizer treatments (N, NC, NPK, and NPKC) and silicate fertilizer treatments (N+S, NC+S, NPK+S, and NPKC+S). The 46-yr input of $2\;ton\;ha^{-1}yr^{-1}$ of silicate fertilizer increased pH 0.6 ~ 1.1 and exchangeable Ca $2.0{\sim}2.4cmol_c\;kg^{-1}$ in silicate fertilizer treatments (N+S, NC+S, NPK+S, and NPKC+S) compared with no silicate fertilizer treatments (N, NC, NPK, and NPKC) because silicate fertilizer included Ca component. Also, available silicate concentrations of silicate fertilizer treatments (N+S, NC+S, NPK+S, and NPKC+S) increased $169mg\;kg^{-1}$ compared to no silicate fertilizer treatments. In Period II ('90~'14), the mean annual Si field balance varied from 62 to $175kg\;ha^{-1}yr^{-1}$ in silicate fertilizer treatments, indicating continuous accumulation of soil Si. Silicon uptake and grain yield of rice had greater differences between N treatment and N+S treatment than other treatments. This showed that the application of silicate fertilizer had greater effect in nutrient-poor soils than in proper nutrient soils. Thus the application of silicate fertilizer led to improvement the fertility of soil and increasement of rice production for the lack of soil nutrients.

• 한국토양비료학회지
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• 제49권6호
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• pp.682-688
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• 2016

Food waste has recognized one of useful sources for potentially agricultural application to supply organic matter and nutrients in arable soil. However, there was little information on application of food waste compost related to the maturity and NaCl content in arable soil. This study evaluated the effect of food waste compost application on yield and fertility in soil under flooding and upland condition. The yields in rice and pepper cultivation decreased with increasing the rate of food waste compost application in soil (p<0.05). Maximum yields of rice ($49.0g\;plant^{-1}$) and pepper ($204g\;plant^{-1}$) were shown at 10 and $30Mg\;ha^{-1}$ of food waste compost application, respectively. The N, P, and K contents in grain and plant residues increased by the application of food waste compost, there was no difference on Na/K ratio in plant tissue among the treatments. Application of food waste compost resulted in the increase of pH, EC, TC, available P contents in soil after crop harvest, especially, which was shown the increase of the CEC and exchangeable sodium percentage (ESP) contents in irrespective of water condition. In conclusion, application of food waste compost in soil was effective on the supply of the organic matter and nutrient. However, it might need caution to apply food waste compost for sustainable productivity in arable soil because of potential Na accumulation.

• 농업과학연구
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• 제41권2호
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• pp.75-83
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• 2014

Recently, a quick drop of air temperature in plastic film houses by adverse weather conditions leads to the occurrence of low temperature damages to growing crops. Chilling injury, defined as a variety of growth restriction occurring below the optimal temperature, is one of environmental factors strongly affecting crop growth and yield. Low temperature causes the restricted evapotranspiration, reduced mineral uptake (P > K > $NO_3{^-}$), and an increase in electrolyte leakage such as K. Despite being different with plant species, an accumulation of soluble carbohydrates such as glucose, fructose, sucrose and starch under chilling condition is well known. A variety of environmental stresses are known to cause oxidative damage to plants either directly or indirectly by triggering an increased level of production of reactive oxygen species (ROS), and, to combat the oxidative damage, plants have the antioxidant defense systems comprising of enzymes, SOD, POD, CAT, GPX and APX, and non-enzymes, ascorbate, gluthathione, ${\alpha}$-tocopherol, phenolic compounds, carotenoid and flavonoids. The aim of this review is to provide basic information to build chilling-indicators and optimal nutrition management under adverse temperature conditions as broadly considering mineral uptake, carbohydrate metabolism and antioxidative defense system.

• 생물환경조절학회지
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• 제15권1호
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• pp.84-90
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• 2006

This study was conducted to anticipate nitrate reduction state in tree through measurement of nitrate reductase activity (NRA) and investigate the effect of nitrogen concentrations (100, 200, 400, and 600 $mg\;L^{-1}$) on growth, the nitrogen content of various tissue, and NRA of pear (Pyrus pyrifolia cv. Niitaka) seedlings in sand culture. Nutrient solutions used in this experiment were adjusted to pH 6.5 and fixed the ratio of ammonium and nitrate to 1:3 and trickle-irrigated 3 times a day. Tree height and dry weight of various organs in seedlings were higher in low nitrogen concentration (100 and 200 $mg\;L^{-1}$) than in high nitrogen concentration (400 and 600 $mg\;L^{-1}$). The shoot growth in 600 $mg\;L^{-1}$ was extremely poor by nitrogen over supply. Increasing the nitrogen concentration, the concentration of nitrate-N in leaves and roots were insignificantly changed but that of stems increased. The accumulation of total and reduced nitrogen in all organs with increasing concentrations of nitrogen supply were increased at 30 days after treatment but those of all organs at 60 and 90 days after treatment were highest in 600 $mg\;L^{-1}$, whereas there were no significant changes among other nitrogen concentration. The in vivo (${+NO_3}^-$) NRA of all organs did not relate to nitrogen concentration but the in vivo (${-NO_3}^-$) NRA of leaves except roots increased with increasing the nitrogen concentration. Therefore, the proper nitrogen concentration to promote growth and nitrate reduction of pear tree was 200 $mg\;L^{-1}$.

• Horticulture, Environment, and Biotechnology : HEB
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• 제59권6호
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• pp.775-786
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• 2018

To test the hypothesis that humic acid (HA), anaerobically digested pig slurry filtrate (APS), and their combination would differently affect the chemical speciation and extractability of metals (cadmium, copper, and zinc) and their uptake by plants, we conducted a pot experiment using wormwood in two texturally contrasting soils (sandy loam and clay loam) collected from a field near an abandoned Cu mine. Four treatments were laid out: HA at $ 23.5g\;kg^{-1}$ (HA), APS at $330mL\;kg^{-1}$ (APS), HA at $ 23.5g\;kg^{-1}$ and APS at $330mL\;kg^{-1}$ (HA + APS), and a control. Each treatment affected the chemical speciation and mobility of the metals, and thereby resulting in variable patterns of plant biomass yield and metal uptake. The APS supported plant growth by increasing nutrient availability. HA supported or hindered plant growth by impacting the soil's water and nutrient retention capacity and aeration, in a soil texture-dependent manner, while consistently enhancing the immobilization of heavy metals. Temporal increases in whole-plant dry matter yield and metal accumulation suggested that the plants were capable of metal hyperaccumulation. The results were discussed in terms of the mobility of metals and plant growth and corroborated by the $^{15}N$ recovery of soil- and plant-N pools under H and HS treatments. Therefore, for effective phytoremediation of polluted soils, an appropriate combination of plant growth promoters (APS) and chelating agents (HA) should be predetermined at the site where chemical stabilization of pollutants is desired.

• Journal of Ecology and Environment
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• 제44권4호
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• pp.212-221
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• 2020

Background: Rapid industrialization has caused various impacts on nature, including heavy metal pollution. However, the impacts of industrialization vary depending on the types of industrializing activity and surrounding environment. South Korea is a proper region because the rapid socio-economical changes have been occurred since the late nineteenth century. Therefore, in this study, we estimate the anthropogenic impacts on an ecosystem from a sediment core of Yonghwasil-mot, an irrigation reservoir on the western coast of Korea, in terms of heavy metal concentrations, nutrient influx, and pollen composition. Results: The sediment accumulation rate (SAR) determined by 210Pb geochronology showed two abrupt peaks in the 1930s and 1950s, presumably because of smelting activity and the Korean War, respectively. The following gradual increase in SAR may reflect the urbanization of recent decades. The average concentrations of arsenic (As), copper (Cu), and lead (Pb) during the twentieth century were > 48% compared to those before the nineteenth century, supporting the influence of smelting activity. However, at the beginning of the twenty-first century, the As, Cu, and Pb concentrations decreased by 19% compared to levels in the twentieth century, which is coincident with the closure of the smelter in 1989 and government policy banning leaded gasoline since 1993. The pollen assemblage and nutrient input records exhibit changes in vegetation cover and water level of the reservoir corresponding to anthropogenic deforestation and reforestation, as well as to land-use alteration. Conclusions: Our results show that the rapid socio-economic development since the twentieth century clearly affected the vegetation cover, land use, and metal pollutions.

• 생물환경조절학회지
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• 제14권1호
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• pp.38-45
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• 2005

본 연구는 딸기 시설재배에서 시비방법이 작물의 생육, 무기원소 흡수 및 토양 중 무기염 집적에 미치는 영향을 구명하기 위하여 2년에 걸쳐 수행하였다. 1차 년도의 시비방법에 따른 딸기 생육에서 초장, 엽장, 관부직경, 엽병장 및 엽폭은 대조구를 제외한 시비구들간의 통계적인 차이는 인정되지 않았다. 10a당 수량에서 (D)가 가장 많았고, (A), 농촌진흥청 추천시비(B), 일본의 도치기시험장 추천시비(C) 및 대조구(E)순으로 수확량이 감소하는 경향이었는데 (D)와 (E) 간의 유의차가 인정되었다. 2차년도 정식 80일 후에 조사한 생육 또한 (E)를 제외한 시비구들간의 통계적인 차이는 인정되지 않았다. 2차년도의 수량 및 평균 과중 등은 1차년도와 유사한 경향을 보였다. 2차년도 토양분석에서 pH는 모두 수용 가능한 범위에 포함되었으나 (A)와 (D)에서 EC가 2.36 및 2.19%$dS{\cdot}m^{-1}$로 측정되었다. (A)와 (D)는 토양 $NO_{3-}N$ 농도가 각각 74.6 및 65.%$mg{\cdot}L^{-1}$, 그리고 Na가 3.71 및 3.53$cmol+kg^{-1}$으로 분석되었다. 이상의 연구결과를 종합할 때 (A) 및 (D)는 수량 증가를 위해 바람직 하나 토양의 $NO_{3-}N$ 및 Na 농도를 높여 염류집적을 심화시키는 시비방법임을 알 수 있었다.

• Applied Biological Chemistry
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• 제44권4호
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• pp.240-245
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• 2001

본 연구에서는 키토산 화합물을 함유한 미량원소 엽면 살포제를 엽채류에 처리하여 질산태 질소 축적 저감 효과를 조사하였다. Ca, Cu, Mn, Mo, Zn 등의 무기영양원소에 키토산과 키토산올리고당을 각각 첨가한 2종류의 미량원소 액제를 온실조건에서 포트에 재배한 상추와 시금치에 정식 후 3주와 4주째에 엽면 살포하였다. 정식 후 5주째에 수확하여 생육량, 엽록소와 미량원소 함량 및 Brix 당도,그리고 질산태 질소와 질산환원효소 활성을 조사하였다. 엽면 살포 액제의 시용을 통하여 작물의 생육 촉진과 함께 질산태 질소의 축적을 10-23% 정도 저감시킬 수 있는 것으로 나타났다. 이러한 결과는 미량원소와 키토산 화합물의 흡수를 통하여 엽록소와 미량원소 함량이 증가되었고 결국 광합성을 비롯한 관련 대사과정들과 질산 환원효소의 활성을 증대시킬 수 있으며 따라서 동시에 질산의 축적을 저감시킬 수 있는 것으로 판단되었다. 이러한 엽면 처리를 통한 질산태 질소의 축적 저감 효과를 극대화하기 위해서는 엽면처리 미량원소의 종류와 함유 비율, 처리 농도, 처리 시기 및 회수의 최적화 등에 대한 검토와 연구가 더 이루어져야 할 것이며, 질소 시비량과 재배환경의 조절 측면의 연구와 대책 또한 동시에 마련되어야 할 것으로 보인다.