• Journal of Microbiology and Biotechnology
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• 제30권11호
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• pp.1688-1696
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• 2020

Soil physical and chemical characteristics, soil potential denitrification rates (PDR), community composition and nirK-, nirS- and nosZ-encoding denitrifiers were studied by using MiSeq sequencing, quantitative polymerase chain reaction (qPCR), and terminal restriction fragment polymorphism (T-RFLP) technologies base on short-term (5-year) tillage field experiment. The experiment included four tillage treatments: conventional tillage with crop residue incorporation (CT), rotary tillage with crop residue incorporation (RT), no-tillage with crop residue retention (NT), and rotary tillage with crop residue removed as control (RTO). The results indicated that soil organic carbon, total nitrogen and NH₄⁺-N contents were increased with CT, RT and NT treatments. Compared with RTO treatment, the copies number of nirK, nirS and nosZ in paddy soil with CT, RT and NT treatments were significantly increased. The principal coordinate analysis indicated that tillage management and crop residue returning management were the most and the second important factors for the change of denitrifying bacteria community, respectively. Meanwhile, this study indicated that activity and community composition of denitrifiers with CT, RT and NT treatments were increased, compared with RTO treatment. This result showed that nirK, nirS and nosZ-type denitrifiers communities in crop residue applied soil had higher species diversity compared with crop residue removed soil, and denitrifying bacteria community composition were dominated by Gammaproteobacteria, Deltaproteobacteria, and Betaproteobacteria. Therefore, it is a beneficial practice to increase soil PDR level, abundance and community composition of nitrogen-functional soil microorganism by combined application of tillage with crop residue management.

• Asian-Australasian Journal of Animal Sciences
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• 제11권3호
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• pp.272-276
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• 1998

Sheep and goats in Pakistan have not been able to produce to the best of their potential. This may primarily be attributed to under feeding and malnutrition. Ranges have been depleted due to overgrazing and mismanagement and are not in position to feed the existing small ruminant population. To overcome the shortage of good quality fodder and balanced feed supply, the alternate means like cereal straws and other crop residues are being commonly used. Sunflower crop residues like stalks and heads provide a good quality forage for livestock. These crop byproducts are rich in crude protein and lower in crude fibre. Their inclusion in the diet of small ruminants at 20, 30 and 40 percent levels in ration has shown significantly (p < 0.05) increased feed intake and weight gain. Daily feed intake was 1,130, 1,180 and 1,750 g for sunflower crop residue, soybean crop residue and wheat straw, respectively, when added at the rate of 20 percent in the ration. The drymatter digestibility of sunflower, soybean crop residues and wheat straw was also comparable. The maximum performance of the animals was observed at the 20 percent level of inclusion of sunflower crop residue in the diet.

• 농약과학회지
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• 제2권3호
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• pp.85-89
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• 1998

작물 생육에 끼치는 토양 잔류 Paraquat의 영향을 검토하고, 더불어 작물 재배 전후의 paraquat 토양 잔류량 변화와 작물체 중 잔류량을 조사하였다. 1996년도 우리나라 과원 paraquat 토양 잔류량 조사에서 최고 수준인 30.2 ppm을 나타낸 사과원 토양에서 생육시킨 콩(품종: 알천콩)과 보리(품종: 사천6호)의 약해, 입모수 및 초장에 대한 paraquat의 영향은 없었다. 토양 잔류량은 파종일에 약 $9{\sim}9.8$ ppm 수준이었으며, 90일간의 재배기간 중 약간 더 감소되었다. 또한 작물체내 paraquat 잔류량은 모두 0.5 ppm 검출한계 미만이었다. 한편 파종일에 토양잔류량을 약 $27{\sim}32$ ppm으로 강화시켰던 토양에서의 콩(품종: 단엽콩)과 보리(품종: 탑골보리)의 생육도 paraquat에 의하여 영향을 받지 않았으며, 작물체내 잔류량도 0.5 ppm 검출한께 미만이었다. Paraquat 토양 잔류량은 파종후 30일 동안 크게 변하지 않았다. 이상의 실험 결과는 paraquat 토양 잔류량 30 ppm 수은 후 작물 생육에 영향을 끼치지 않으며, 또한 현재 우리나라 과원 토양에서의 작물이 재배될 경우 작물 생육 및 잔류에 있어서 문제가 없음을 시사하여 주었다.

• 한국작물학회지
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• 제47권2호
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• pp.137-141
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• 2002

Decomposition of green manure is necessary for the nutrient supply in farm soil. Hairy vetch as a green manure is superior to other winter legumes in terms of wintering ability and N accumulation. This experiment was carried out to investigate the decomposition and N release of hairy vetch and its effect on rice production as the following crop in paddy field. Decomposition of hairy vetch placed by soil depth of 0, 10 and 20cm at transplanting time was investigated by mesh bag method, which was enclosed chopped residue in mesh bags. The fate of $^{15}$ N derived from $^{15}$ N-labeled hairy vetch was investigated at harvest in three levels of N fertilization. Grain yield of the transplanted paddy rice cultured with hairy vetch as starter N were compared with that of applying urea as starter N in the field. Hairy vetch residue decomposed very rapidly both in transplanted and dry-seeded paddy field. In transplanted paddy field, hairy vetch residue lost 72-81 % and 86-90% of its weight after one and five month, respectively, as affected by incorporation depth. The C/N ratio of the decomposing vetch residue increased sharply during the early stages and after then, decreased slowly. The amounts of N and P released from the vetch were about 90% and 97% of initial content after one month, respectively. Recoveries of hairy vetch-$^{15}$ N by rice plant were 30.6, 34.6 and 35.7% in 0, 6 and 12 kg urea-N 10 $a^{-l}$ application, respectively, indicating that N fertilization increased the recovery of hairy vetch. $^{15}$ N. Hairy vetch residue incorporated as starter maintained significant N $H_4$$^{+}$-N concentration in soil water of plow layer until effective tillering stage. Grain yield in the plot applied with hairy vetch was not significantly different from that in the plot with urea. We concluded that hairy vetch incorporation could substitute starter N fertilization and showed possibility to reduce N amount of top-dressing.g.g.

• 한국작물학회:학술대회논문집
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• 한국작물학회 2020년도 춘계학술대회
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• pp.15-15
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• 2020

• 한국토양비료학회지
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• 제46권5호
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• pp.379-385
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• 2013

Although sorghum residue production was estimated to be $8{\sim}10Mg\;ha^{-1}$, most sorghum straw was used to be burnt or removed after harvest. This experiment was conducted to evaluate the effect of the incorporation of manured sorghum residues on soil physical properties from 2010 to 2012 in the converted paddy field. Five treatment with 3 replication consisted of control, inorganic fertilizer (NPK), manured residues, sorghum stover and sawdust manure. The incorporation level of organic source was $10Mg\;ha^{-1}$ without inorganic fertilizer NPK. The investigated physical parameters were bulk density (BD), porosity, water stability aggregate (WSA), water infiltration rater (WIR), penetration resistance (PR) and soil water retention characteristics (WRC) with soil depth. The incorporation of manured sorghum residues improved WIR significantly over inorganic fertilizer (NPK), sorghum residues and sawdust manure. The BD by incorporating with manured residues on sorghum was reduced significantly with crop residue over plot of NPK and sawdust. Significant increase in WSA was observed with stubble incorporation alone or manured sorghum residues. Soil WRC were significantly enhanced with manured sorghum residue incorporated without NPK. The average PR at 0~15 cm was 0.54 MPa for manured sorghum residues. For sawdust manure plot it was 0.42 MPa, for Sawdust manure plot 0.39 MPa and for NPK plot 0.54 MPa.

• 한국작물학회:학술대회논문집
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• 한국작물학회 2023년도 춘계학술대회
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• pp.180-180
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• 2023

• 한국환경농학회지
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• 제36권3호
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• pp.184-192
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• 2017

BACKGROUND: This study was performed to evaluate the residue dissipation of boscalid and spinetoram on crown daisy and sweet pepper affected by the morphology of the crop. The half-lives and dissipation rate constants for boscalid and spinetoram on crown daisy and sweet pepper were calculated. And then lower limit of 95% confidence interval for dissipation rate constant could be used to propose the pre-harvest residue limit. METHODS AND RESULTS: The pesticide products diluted according to the pesticide label were applied one time on crown daisy and sweet pepper at 2 field sites, respectively. Initial concentration of boscalid and spinetoram on crown daisy after application were in the range of 72.80~117.15 mg/kg and 2.82~4.67 mg/kg, respectively. And Initial concentration of boscalid and spinetoram on sweet pepper were in the range of 1.58~1.62 mg/kg and 0.10~0.21 mg/kg, respectively. Boscalid and spinetoram for crown daisy dissipted below the maximum residue limit(MRL) at 10 and 2 days after application, respectively. All residues concentration of boscalid and spinetoram for sweet pepper below the MRL at 0 day after application. The half-lives based on dissipation rate constant for boscalid and spinetoram on crown daisy were 4.2~4.9 days and 3.0~2.4 days respectively. And the half-lives for boscalid and spinetoram on sweet pepper were 6.7~7.0 days and 2.8~4.0 days respectively. CONCLUSION: The difference in initial concentration of boscalid and spinetoram among crop commodities were due to different crop morphology with larger surface areas. This study was suggested that pre-harvest residue limit would be calculated from lower limit of 95% confidence interval for dissipation rate constant and would be useful to protect consumers by controlling the pesticide residues in crop.

• 농업과학연구
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• 제43권4호
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• pp.634-640
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• 2016

The objective of this study was to evaluate the effectiveness of using HR-GC/MS for the rapid screening of dieldrin residues in soils. Persistent organic pollutants (POPs) of organochlorine pesticides such as dieldrin, were analyzed in sedimentary rock and granite rock collected from greenhouses, Niigata, Japan. Dieldrin remains in Japanese farming soils, more than 40 years after their use as insecticides was prohibited. The averages in soil moisture ranged from 2.79% to 7.20% in soils derived from sedimentary rock and from 25.59% to 31.40% in soils derived from granite rock. Mean concentrations of dieldrin residues in sedimentary rock and granite rock were $39.7ng\;g^{-1}$ and $40.51ng\;g^{-1}$, respectively. Dieldrin residue was detected at a slightly higher concentration in granite rock than sedimentary rock samples. There was no consistency between the two soils or between surface and subsurface soils. The coefficients of variation of the two soils were 10.6% and 8.7%, respectively. These results suggest that our high-resolution mass spectrometry detector (HR-GC/MS) is effective at analyzing residual organochlorine pesticides in soil. In order to increase the precision and sensitivity for chemical analysis of POPs, high-resolution gas chromatography coupled with a HR-GC/MS is highly recommended.

• 한국환경농학회지
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• 제30권4호
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• pp.432-439
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• 2011

BACKGROUND: An official analytical method was developed to determine etofenprox residues in agricultural commodities using high-performance liquid chromatography (HPLC). METHODS AND RESULTS: The etofenprox residue was extracted with acetone from representative samples of five raw products which comprised rice grain, apple, mandarin, cabbage, and soybean. The extract was then serially purified by liquid-liquid partition and Florisil column chromatography. For rice and soybean samples, acetonitrile/n-hexane partition was additionally coupled to remove nonpolar lipids. Reversed phase HPLC using an octadecylsilyl column was successfully applied to separate etofenprox from co-extractives. Intact etofenprox was sensitively detected by ultraviolet absorption at 225 nm. Recovery experiment at the quantitation limit validated that the proposed method could apparently determine the etofenprox residue at 0.02 mg/kg. Mean recoveries from five crop samples fortified at three levels in triplicate were in the range of 93.6~106.4%. Relative standard deviations of the analytical method were all less than 10%, irrespective of crop types. A selected-ion monitoring LC/mass spectrometry with positive atmospheric-pressure chemical ionization was also provided to confirm the suspected residue. CONCLUSION(s): The proposed method is simple, rapid and sensitive enough to be employed in routine inspection or monitoring of agricultural products for the etofenprox residue.