• Environmental Engineering Research
• /
• v.12 no.4
• /
• pp.136-147
• /
• 2007

In an effort to identify possible microbes for seeking bioagents for remediation of herbicide-contaminated soils, seven species of phototrophic nonsulfur bacteria (Rhodobacter capsulatus and sphaeroides, Rhodospirillum rubrum, Rhodopseudomonas acidophila, blastica and viridis, Rhodomicrobium vannielii) were grown in the presence of the herbicide, butachlor, and bacterial growth rates and nitrogen fixation were measured with different carbon sources. Under general conditions, all species showed 17-53% reductions in growth rate following butachlor treatment. Under nitrogen-fixing conditions, Rb. capsulatus and Rs. rubrum showed 1-4% increases in the growth rates and 2-10% increases in nitrogen-fixing abilities, while the other 5 species showed decreases of 17-47% and 17-85%, respectively. The finding that Rp. acidophila, Rp. blastica, Rp. viridis and Rm. vannielii showed stronger inhibitions of nitrogenase activity seems to indicate that species in genera Rhodobacter and Rhodospirillum are less influenced by butachlor than those in Rhodopseudomonas and Rhodomicrobium in terms of nitrogen-fixing ability. Overall, nitrogenase activity was closely correlated with both growth rate and glutamine synthetase activity (representing nitrogen metabolism). When the carbon sources were compared, pyruvate (three carbons) was best for all species in terms of growth rate and nitrogen fixation, with malate (four carbons) showing intermediate values and ribose(five carbons) showing the lowest; these trends did not change in response to butachlor treatment. We verified that each of the 7 species had a plasmid ($12.2{\sim}23.5\;Kb$). We found that all 7 species could use butachlor as a sole carbon source and 3 species were controlled by plasmid-born genes, but it is doubtful whether plasmid-born genes were responsible to nitrogen fixation.

• Journal of Animal Science and Technology
• /
• v.61 no.4
• /
• pp.185-191
• /
• 2019

The aim of this study was to evaluate different herbicides for optimum growth, yield and nutritive value of corn-soybean mixed forage under randomized complete block design. The experimental site was selected and divided equally into 3 blocks. Each block was further divided into 5 plots that each plot had 15 square meter space ($3{\times}5$). Five herbicidal treatments were randomly applied over 5 plots and herbicides were used under 5 herbicidal treatments, viz. 1) No herbicide (control); 2) Pendimethalin; 3) Linuron; 4) S-metolachlor and 5) Ethalfluralin. The collected data were analyzed using ANOVA through SAS 9.1.3 software. The results indicated that growth characteristics were not influenced (p > 0.05) by any herbicide. However, arithmetically corn stalk height was highest in the field of Pendimethalin treatment, whereas highest soybean height was found in the field of S-metolachlor. Arithmetically dry matter (DM) yield was increased with herbicidal treatments as compared to that of control treatment. Relatively highest DM yield (130%) was recorded in the treatment of Ethalfluralin followed by Pendimethalin (126%), S-metolachlor (126%) and Linuron (108%) as compared to that of control treatment. The weed emergence was significantly reduced in all herbicidal treatments as compared to that of control (p > 0.05), but the difference among herbicidal treatments was non-significant. It was concluded that weed emergence can be effectively controlled by use of any tested herbicide. However, optimum DM yield can be achieved through using herbicides; Ethalfluralin, Pendimethalin and S-metolachlor.

• Korean Journal of Environmental Agriculture
• /
• v.28 no.2
• /
• pp.186-193
• /
• 2009

The removal efficiency of herbicide glyphosate in a drinking water treatment system was investigated. Four major processes of a drinking water treatment system were selected and experiments were performed separately including; treatments by sodium hypochlorite (NaOCl), a sedimentation process by PAC (polyaluminum chloride), ozonation and a GAC (granular activated carbon) treatment. In the sodium hypochlorite experiment, about 50% of the glyphosate was removed by 2 mg/L of hypochlorite and more than 90% was eliminated when 5 mg/L of NaOCl was applied. Also, AMPA, the main metabolite of glyphosate, was treated with hypochlorite. More than 30% of the AMPA was removed by 2 mg/L of hypochlorite and 50% by 5 mg/L. In the PAC experiment, it was determined that more than 60% could be removed. Further experiments were performed and the results indicated that the removed amount was dependent upon the amount of soil and upon the properties of the soil especially that of clay minerals. Ozonation could oxidize glyphosate to its byproducts at about a level of 50%. In contrast, when 1 mg/L of glyphosate was treated with GAC, the amount removed was negligible. The results of this experiment were conclusive. We confirmed that drinking water, which has been contaminated with water polluted with glyphosate can be effectively purified by the application of the drinking water treatment processes currently used.

• Weed & Turfgrass Science
• /
• v.3 no.4
• /
• pp.323-328
• /
• 2014

This study was conducted to find out the effects of aerial application by unmanned helicopter (AAUH) on controlling weeds under water-seeded rice cultivation. Foliar herbicide (bentazone sodium + fenoxaprop-P-ethyl) was applied with diluted 8-times (standard concentration pest control) as AAUH. Foliar herbicide treatment with standard and two times amount were little damage, but with more than three times amount showed great damage in rice growth. Six annual and two perennial weeds were major weeds occurred in the experimental paddy field. On foliar herbicide treatment 25 days after direct seeding, AAUH showed high control values against weeds (96.3% for annual weeds and 99.8% for perennial weeds). There was no significant difference in weed control values between AAUH and conventional application. There was no spray injury against rice plants with aerial application. In the experiment for good spray timing (15, 20 and 25 days after direct seeding) 15 days showed highest weed control values with 98.5% to annual weeds and 99.8% to perennial weeds and no spray injury.

• Korean Journal of Weed Science
• /
• v.2 no.2
• /
• pp.146-151
• /
• 1982

Herbicide mixtures, butachlor + naproanilide, CG113 + naproanilide and benthiocarb + naproanilide were tested in order to control Sagittaria pygmaea Miq., one of the most serious perennial weeds in paddy field of Honam area. 92% of tuber of Sagittaria pygmaea Miq. was distributed within 9cm from the soil surface and number of emerged Sagittaria pygmaea Miq. increased until 40 days after rice transplanting but decreased thereafter. Number and dry weight of survived Sagittaria pygmaea Miq. were much less in butachlor + naproanilide, CG 113 + naproanilide and benthiocarb + naproanilide treatments than perfluidone and it was controlled by up to 95% by mixture treatments. Number of rhizome of Sagittaria pygmaea Miq. was decreased by all herbicide treatments and especially mixture treatment significantly reduced rhizome formation compared to perfluidone and 2.4 -D treatments. CG113 + naproanilide treatment caused phytotoxicity that tip of leaf sticked to leaf sheath curvedly in Indica ${\times}$ Japonica rice, Iri 358, but it was recovered within 10 days after herbicide treatment.

• Korean Journal of Weed Science
• /
• v.18 no.4
• /
• pp.325-332
• /
• 1998

This study was carried out to investigate the adsorption and the movement of herbicide fenoxaprop-P-ethyl in the silty clay soil(SiC) and the sandy loam soil(SL). Fifteen percent of the added herbicide was adsorbed within 30 min after shaking, and a quasi-equilibrium was reached after 8 to 14 h. The time required for 50% adsorption was 15.8 h in the SiC and 19.3 h in the SL. The equilibrium adsorption isotherm was followed by the Freundlich equation and the Kd was 3.86 in the SiC and 2.32 in the SL. The herbicide in the soil columns flooded with 3 cm water depth and eluted at 0.8 cm/day was leached to 6 cm and 8 cm depth at 7 and 21 days after the treatment, respectively. However, the movement was widened with increased amount of leaching water. The herbicide in the field soils was moved up to 6 cm and 8 cm depth at 14 and 56 days after the treatment, respectively. However, the large amount of the applied herbicide was distributed in 0~2 cm profile in all of the soils examined. Half-life of the chemical in soils was shorter than 7 days and the time to 90% degradation was about 4 weeks. The results indicate that the herbicide has relatively small mobility and short persistence.

• Korean Journal of Soil Science and Fertilizer
• /
• v.43 no.1
• /
• pp.36-43
• /
• 2010

Changes in runoff and soil erosion at slightly hilly erosive plots with pear trees over a three-year period were monitored under two distinct types of weed treatment by herbides : (1) pre-emergence herbicide with glyphosate; (2) post-emergence herbicide with paraquat. The numbers of rainfall events from June to Nov for three years of experimental periods were approximately 50 times in the plots having 5.5%to 10.2%slope at an altitude of 125 m. The steady-state infiltration rate was generally increased in the bare plot from which all weeds were removed while it was decreased in the herbicide treated plots and control. The runoffs from the control plot during the experimental periods were always less than those from plots of the herbicide-treated and the bare. The runoff under the same rainfall intensity was decreased in the order of bare, glyphosate, paraquat, and control. This results indicated that the removal time of weed by the different types of herbicides might influenced the runoff rate. For the first two years of the experimental periods, loss of fine fraction was much greater than that of coarse fraction while soil loss was correlated neither with total rainfall nor amount of runoff. The soil erosion rate under the same rainfall intensity was increased in the order of control, glyphosate, paraquat, and bare plot. However, there were not much differences in the soil loss for all plots under a relatively lower rainfall intensity less than 30 mm $day^{-1}$, resulting in rainfall intensity was important factor on soil erosion.

• Journal of Biosystems Engineering
• /
• v.41 no.4
• /
• pp.294-303
• /
• 2016

Purpose: This study aimed to evaluate the profitability of four selective mechanization systems in rice cultivation. Methods: Field experiments were conducted in the farmers' field during the wet season (June to November) of 2015 in Bangladesh. Mechanization systems were applied to evaluate four different selective levels (treatment) in eleven consequent operations. Seedlings were raised in a traditional seedbed and trays for manual and mechanical transplanting, respectively. Land preparation, irrigation, fertilizer, pesticide, carrying, and threshing and cleaning operations were performed using the same method in all the experimental plots. The mechanical options in the transplanting, weeding, and harvesting operations were changed. The mechanization systems were $S_1$ = hand transplanting + hand weeding + harvesting by sickle, $S_2$ = mechanical transplanting + Bangladesh Rice Research Institute (BRRI) weeder + reaper, $S_3$ = mechanical transplanting + BRRI power weeder + reaper, and $S_4$ = mechanical transplanting + herbicide + reaper. This experiment was performed in a randomized complete block design with four replications. Power tiller, rice transplanter, BRRI weeder, BRRI power weeder, self-propelled reaper, BRRI open drum thresher, and BRRI winnower were used in the respective operations. Accordingly, the techno-economic performances of the different technologies were calculated and compared with those of the traditional system. Results: The mechanically transplanted plot produced 6-10% more yield than the hand transplanted plot because of the use of tender-aged seedlings. Mechanical transplanting reduced 61% labor and 18% cost compared to manual transplanting. The BRRI weeder, BRRI power weeder, and herbicide application reduced 74, 91, and 98% labor, respectively. The latter also saved 72, 63, and 82% cost, respectively, compared to hand weeding. Herbicide application reduced the substantial amount of labor and cost in the weeding operation. Mechanical harvesting also saved 96% labor and 72% cost compared to the traditional method of harvesting using sickle. Selective mechanization saved 15-17% input cost compared to the traditional method of rice cultivation. Conclusions: Mechanical transplanting with the safe use of herbicide and harvesting by reaper is the most cost- and labor-saving operation. The method might be the recommended set of selective mechanization for enhancing productivity.

• Journal of The Korean Society of Clinical Toxicology
• /
• v.19 no.2
• /
• pp.93-99
• /
• 2021

Purpose: Nutritional status and support in critically ill patients are important factors in determining patient recovery and prognosis. The aim of this study was to analyze the early nutritional status and the methods of nutritional support in critically ill patients with acute poisoning and to evaluate the effect of nutritional status on prognosis. Methods: A retrospective study was conducted in tertiary care teaching hospital from January 2018 to December 2020. in an emergency department of university hospital, 220 patients who were stayed more than 2 days of poisoning in intensive care unit were enrolled. Results: 155 (70.5%) of patients with acute poisoning had low-risk in nutritional risk screening (NRS). Patients with malignancy had higher NRS (low risk 5.2%, moderate risk 18.5%, high risk 13.2%, p=0.024). Patients of 91.4% supplied nutrition via oral route or enteral route. Parenteral route for starting method of nutritional support were higher in patients with acute poisoning of herbicide or pesticide (medicine 3.2%, herbicide 13.8%, pesticide 22.2%, p=0.000). In multivariate logistic regression analysis, herbicide or pesticide intoxication, higher risk in NRS and sequential organ failure assessment over 4.5 were affecting factor on poor recovery at discharge. Conclusion: NRS in patients intoxicated with herbicide or pesticide were higher than that in patients intoxicated with medicine intoxication. Enteral nutrition in patients intoxicated with herbicide or pesticide was less common. Initial NRS was correlated with recovery at discharge in patient with intoxication. It is expected to be helpful in finding patients with high-risk nutritional status in acute poisoning patients and establishing a treatment plan that can actively implement nutritional support.

• The Korean Journal of Ecology
• /
• v.24 no.3
• /
• pp.157-168
• /
• 2001

Herbicides have been used to control weeds for decades. If detoxification upon exposure to herbicides requires considerable amounts of energy, it could affect the pattern of resource allocation to growth and reproduction of crops. We examined the effects of three levels of a herbicide (Control, Low, and High) on germination, growth and reproductive characters of Glycine max treated twice, i.e., before and after seed germination. Since flowering time of G. max was separated into two groups, flowering time was also considered as a variable in this study. The rate of seed germination tended to be higher at the low level of herbicide compared to other levels. Chlorosis and shape variation of leaves were apparent after the second herbicide treatment, but completely disappeared after six weeks of treatment. The herbicide effects on growth characters were somewhat different between early and late flowering plants, but plants treated with both low and high levels of herbicide reduced their growth compared to those in the control group regardless of flowering time. Plants at the high level of herbicide exhibited the highest growth rate later in the season, suggesting that plants compensated to some extent for reduced growth. However, growth reduction among plants at the high level of herbicide was persistent until the end of growing season. Among plants flowered late in the season, plants in the control level bore a higher number of nodules per plant than those in other levels; such a pattern did not exist among plants flowered early in the season. Plants treated with low and high levels of herbicide produced a lower number of flowers than those in the control. Thus, the herbicide examined affected not only the growth and reproductive characters of non-target crops but also the development and growth of root nodules.