• The Korean Journal of Pesticide Science
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• v.8 no.1
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• pp.38-45
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• 2004

To elucidate the photolysis characteristics of the insecticide imidacloprid in the environment, $[^{14}C]$imidacloprid was treated into water and paddy soil-water system. In water system, the amount of $^{14}C$-radioactivity distributed in aqueous phase was rapidly increased up to 80% of total $^{14}C$ in water during 7 days of exposure to sunlight. Also, the amounts of imidacloprid in water at day 0 and 3 days after treatment were 1.2461 and 0.8594 mg/kg, respectively, not being detected 7 days after treatment, indicating rapid degradation of imidacloprid in water by sunlight. One photodegradation product, imidacloprid urea, in which the $N-NO_2$ moiety of imidacloprid was replaced by oxygen, was detected from water in water and water-paddy systems. The amount of the metabolite detected from water in water system was 0.0112 mg/kg 1 day after treatment and reached the top concentration of 0.0391 mg/kg 7 days after treatment. In case of water-paddy system, its amount was 0.0117 mg/kg 1 day after treatment and reached the highest concentration of 0.0259 mg/kg 3 days after treatment. Rapid transformation of imidacloprid into polar compounds continued until 7 days after treatment, considering that 80% of $^{14}C$ in water distributed in aqueous phase 7 days after treatment, amount of imidacloprid was 1.6538 mg/kg at day 0 and 0.8785 mg/kg 1 day after treatment, not being detected after 15 days, indicating rapid degradation of imidacloprid in water-paddy soil system by sunlight. The direct degradation of imidacloprid to imidacloprid urea would be a major photodegradation pathway in water and water-paddy soil systems.

• Korean Journal of Soil Science and Fertilizer
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• v.48 no.1
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• pp.44-49
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• 2015

Urea has been the most useful N-source, due to lower cost per unit of N. But nitrogen use efficiency of urea may be reduced because of losses from agricultural system by volatilization of ammonia to atmosphere. This study was conducted to evaluate the nitrogen efficiency and growth of hot pepper (Capsicum annuum L.) by mixed treatment with nitrogen and zeolite. They were treated with N $161kg\;ha^{-1}$, N $230kg\;ha^{-1}$, nitrogenzeolite mixture (NZM) $161kg\;ha^{-1}$, NZM $230kg\;ha^{-1}$ and N $0kg\;ha^{-1}$, respectively. In the soil chemical properties after experiment, soil pH decreased but available $P_2O_5$, EC and total nitrogen increased in nitrogen-zeolite mixture treatment. $NO_3-N$ content in the soil showed the highest level in NZM $230kg\;ha^{-1}$. NZM $161kg\;ha^{-1}$ treatment increased growth and yield of hot pepper compared to urea alone. Nitrogen utilization efficiency of hot pepper plant was 47.15% at the treatment of NZM $161kg\;ha^{-1}$, while 36.74% at N $230kg\;ha^{-1}$. These results showed that application of mixture of nitrogen and zeolite had positive influence to improve the efficiency of nitrogen utilization and increase of red pepper yield.

• Korean Journal of Environmental Agriculture
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• v.18 no.4
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• pp.327-331
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• 1999

The purpose of this study was to find out the effects of slow-released nitrogen fertilizer (SRF) on the growth and yield of Chinese cabbage. The SRF used in this study was prepared by embedding urea into a waste paper slum. The underwater dissolution rate of SRF was very rapid during the first 12 hours and 60.4% of the embedded nitrogen was released after 72 hours. The SRF and urea was applied as nitrogen source and growth. yield, yield components, nitrogen uptake of Chinese cabbage were investigated a pot experiment. Maximum leaf length of Chinese cabbage was not different between SRF and urea treatments. Length and wish of head, number of leaf per head and fresh weight of Chinese cabbage were higher in SRF treatment than those in urea treatment, but the differences were not statistically significant. Comparing to the urea treatment, nitrogen content and nitrogen uptake efficiency of Chinese cabbage were significantly higher in SRF treatment. After the experiment, total soil nitrogen contents were not different between the SRF and urea treatments.

• Asian-Australasian Journal of Animal Sciences
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• v.15 no.4
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• pp.522-527
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• 2002

The experiment was conducted for a period of 56 days with twelve Bangladeshi bull calves of average body weight of $127.20{\pm}11.34$ kg. The calves were divided into 3 groups having 4 animals in each. The animals were fed urea-treated rice straw designated as A) 4% urea-treated rice straw, B) 4% urea+4% soybean-treated rice straw and C) 4% urea+6% soybean-treated rice straw. In addition, all the animals were supplied 2 kg green grass, 350 g Til-oil-cake and 100 g common salt per 100 kg body weight of animals. Straw was treated with 4% urea solution and soybean meal at 4 and 6% were added to treated straw and kept for 48 h in double layer polythene bags under anaerobic condition. Urea treatment improved crude protein (CP) content of rice straw from 2.68 to 8.70% and it was further increased by 10.74 and 12.12% with the addition of 4 and 6% soybean meal. Dry matter (DM) intake (kg) was higher (p<0.05) in C (4.2) followed by B (4.1) and A (4.0). Crude protein intake was significantly higher (p<0.05) in group B and C than group A. Total live weight gains were 20.2, 24.8 and 25.6 kg for calves of group A, B and C respectively (p<0.01). The addition of soybean meal to treated rice straw did not affect the coefficients of digestibility of DM, OM, EE and NFE. However, CP and CF digestibility were significantly higher in group B and C (p<0.05). The values for digestible crude protein (DCP), digestible ether extract (DEE), digestible nitrogen free extract (DNFE) and total digestible nutrients (TDN) were significantly (p<0.05) higher in diet C and B in comparison to diet A, but there were no significant difference in digestible organic matter (DOM) and digestible crude fibre (DCF) value among the groups. It may be concluded that 4% urea treated rice straw can be fed to growing bull calves with 2 kg green grass and a small quantity of concentrate without any adverse effect on feed intake and growth. Moreover, soybean meal at 4 and 6% can be added to urea treated rice straw at the time of treatment for rapid hydrolyzing of urea, which resulted an improvement in nutrient digestibility and better utilization of rice straw for growth of growing bull calves.

• Journal of The Korean Society of Inherited Metabolic disease
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• v.5 no.1
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• pp.76-87
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• 2005

Various disorders cause hyperammonemia during childhood. Amongthem are those caused by inherited defects in urea synthesis and related metabolic pathways. These disorders can be grouped into two types: disorders of the enzymes that comprise the urea cycle, and disorders of the transporters or metabolites of theamino acids related to the urea cycle. Principal clinical features of these disorders are caused by elevated levels of blood ammonium. Additional disease-specific symptoms are related to the particular metabolic defect. These specific clinical manifestations are often due to an excess or lack of specific amino acids. Treatment of urea cycle disorders and related metabolic diseases consists of nutritional restriction of proteins, administration of specific amino acids, and use of alternative pathways for discarding excess nitrogen. Although combinations of these treatments are extensively employed, the prognosis of severe cases remains unsatisfactory. Liver transplantation is one alternative for which a better prognosis is reported.

• Asian-Australasian Journal of Animal Sciences
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• v.4 no.3
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• pp.235-240
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• 1991

A CRD experiment with thirty growing cross bred calves were assigned at random to three treatments rations. 1) $T_0$, 0% Urea + 20% M. O. cake, 2) $T_1$, 1% Urea + 10% M. O. cake and 3) $T_2$, 2% Urea + 0% M. O. cake to develop a rice straw based ration for ruminants. Sweetish odour and yellowish colour were observed in good recovered silage. Organic matter varied from 87.45% to 89.63% whereas crude protein varied from 14.0% to 14.5% in each treatment. No significant differences were found among the nutrient composition of the ration. The dry matter in take (DMI) and dry matter digestibility was higher in $T_0$ (0% Urea) than those of ration containing 1% ($T_1$) and 2% Urea ($T_2$). The organic matter digestibility decreases with increasing doses of urea. The crude protein & nitrogen-free-extract digestibility were found higher in the ration $T_1$ containing 1% urea whereas crude fibre digestibility and available metabolizable energy (ME) were higher in $T_0$ containing no urea as compared to $T_1$ and $T_2$. Total digestible nutrient (TDN) decreases with the increase of urea level. The highest feed efficiency was found in $T_0$ having no urea and lowest was in $T_2$. The animals gained in weights from each ration. Highest gain in weight was found in $T_0$ ration, then followed $T_1$, and $T_2$. This is due to natural protein available in M. O. cake only. It is concluded that supplemetation of urea or M. O. cake with readily available energy source as molasses upto 20% of total dietary dry matter in a complete ration may increase the intake of low quality fibrous roughage only when nitrogen and mineral are not limiting factor.

• Korean Journal of Soil Science and Fertilizer
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• v.30 no.2
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• pp.99-107
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• 1997

The effect of easily decomposable organic carbon (methanol) application on the behavior of nitrogen derived from surface-applied urea in submerged soil was investigated. Two rates of urea (150 & $300kg-N\;ha^{-1}$) and three levels of methanol (2, 4, 8 ml) were applied to 10 g soil samples. The samples were incubated for 30 days under submerged conditions. The flood water and the soil were sampled for analysis of urea-N, $NH_4-N$ and $NO_3-N$ every 10 days. Urea-N in flood water and in soil at the rate of $150kg-N\;ha^{-1}$ and that in flood water at the rate of $300kg-N\;ha^{-1}$ were not detected but the urea-N concentration in soil at the rate of $300kg-N\;ha^{-1}$ with 8 ml methanol treatment was 4.7 on the 10th day from incubation. $NH_4-N$ concentrations in flood water and in soil increased with increasing urea application rates whereas they decreased with increasing methanol treatment. $NO_3-N$ concentration in flood water and in soil were similar regardless of the urea and methanol application rates. The total amount of $NH_4-N$ in flood water and in soil decreased with increasing methanol treatment, 0 ml & 2 ml, whereas the total amounts of $NO_3-N$ in both flood water and soil increased slightly at higher rates of methanol treatment, 4 ml & 8 ml. The total amount of $NH_4-N$ in both flood water and soil increased up to 20 days of incubation whereas that of $NO_3-N$ in flood water and in soil decreased over incubation time.

• Asian-Australasian Journal of Animal Sciences
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• v.16 no.11
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• pp.1610-1613
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• 2003

The aim of the experiment was to study the changes in the activities of various rumen fibre degrading enzymes due to the feeding of chemically treated mustard (Brassica campestris) straw in sheep. Mustard straw (MS) (<5 cm particle size) was treated either with urea (4% (w/w), or with 2% sodium hydroxide (NaOH), or with alkaline hydrogen peroxide (2% NaOH and 1.5% hydrogen peroxide ($H_2O_2$)) and/or supplemented with 2% (w/w) urea. Seven maintenance type rations were prepared using MS (70 parts) with molasses (5 parts) and concentrate (25 parts). They were untreated MS (CMS), urea treated MS (UMS), urea supplemented MS (MSUS), alkali treated MS (AMS), alkali treated and urea supplemented MS (AMS-US), alkali $H_2O_2$ treated MS (AHMS) and alkali $H_2O_2$ treated and urea supplemented MS (AHMS-US). They were then compressed into a complete feed block with the help of block making machine. Forty two male hoggets of Malpura breed sheep were equally distributed into each treatment group and (were) offered feed and water ad libitum. At the end of 21 days of feeding trial, rumen liquor was collected through stomach tube from three animals in each group at 0 h, 4 h, 8 h, 12 h of post feeding. Results showed that the level of enzyme varied from 8.52 to 11.12, 40.85 to 50.37, 3.22 to 3.78, 2.09 to 2.77 and 31.44 to 44.24 units/100 ml SRL respectively for carboxymethyl cellulase (CMCase), $\alpha$-amylase, microcrystalline cellulase (MCCase), filter paper (FP) degrading enzyme and $\alpha$-glucosidase. Processing of MS affected the enzyme activities, in a way, that NaOH and AHP treatment significantly reduced CMCase and FP degrading enzyme. The effect of urea treatment showed an increase in the activity of MCCase and $\alpha$-glucosidase. But the supplementation of urea increased the activity of CMCase, FP degrading enzyme and $\alpha$-glucosidase. The CMCase, $\alpha$-amylase, $\alpha$-glucosidase activities were highest at 4hr whereas MCCase and FP degrading enzyme had maximum activities at 12 h post feeding Results suggested that MS might need longer time in the rumen for its effective degradation.

• Korean Journal of Environmental Agriculture
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• v.28 no.3
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• pp.233-237
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• 2009

It has widely been observed that the effect of elevating atmospheric $CO_2$ concentrations on rice productivity depends largely on soil N availabilities. However, the responses of ammonia volatilization from flooded paddy soil that is an important pathway of N loss and thus affecting fertilizer N availability to concomitant increases in atmospheric $CO_2$ and temperature has rarely been studied. In this paper, we first report the interactive effect of elevated $CO_2$ and temperature on ammonia volatilization from rice paddy soils applied with urea. Urea labeled with $^{15}N$ was used to quantitatively estimate the contribution of applied urea-N to total ammonia volatilization. This study was conducted using Temperature Gradient Chambers (TGCs) with two $CO_2$ levels [ambient $CO_2$ (AC), 383 ppmv and elevated $CO_2$ (EC), 645 ppmv] as whole-plot treatment (main treatment) and two temperature levels [ambient temperature (AT), $25.7^{\circ}C$ and elevated temperature (ET), $27.8^{\circ}C$] as split-plot treatments (sub-treatment) with triplicates. Elevated temperature increased ammonia volatilization probably due to a shift of chemical equilibrium toward $NH_3$ production via enhanced hydrolysis of urea to $NH_3$ of which rate is dependent on temperature. Meanwhile, elevated $CO_2$ decreased ammonia volatilization and that could be attributed to increased rhizosphere biomass that assimilates $NH_4^+$ otherwise being lost via volatilization. Such opposite effects of elevated temperature and $CO_2$ resulted in the accumulated amount of ammonia volatilization in the order of ACET>ACAT>ECET>ECAT. The pattern of ammonia volatilization from applied urea-$^{15}N$ as affected by treatments was very similar to that of total ammonia volatilization. Our results suggest that elevated $CO_2$ has the potential to decrease ammonia volatilization from paddy soils applied with urea, but the effect could partially be offset when air temperature rises concomitantly.

• Asian-Australasian Journal of Animal Sciences
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• v.2 no.3
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• pp.533-534
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• 1989